Fossil

      }

      /* echo the sql statement if echo on */
      if( pArg && pArg->echoOn ){
        const char *zStmtSql = sqlite3_sql(pStmt);
        fprintf(pArg->out, "%s\n", zStmtSql ? zStmtSql : zSql);
      }

      /* Output TESTCTRL_EXPLAIN text of requested */
      if( pArg && pArg->mode==MODE_Explain ){
        const char *zExplain = 0;
        sqlite3_test_control(SQLITE_TESTCTRL_EXPLAIN_STMT, pStmt, &zExplain);
        if( zExplain && zExplain[0] ){
          fprintf(pArg->out, "%s", zExplain);
        }
      }

      /* perform the first step.  this will tell us if we
      ** have a result set or not and how wide it is.
      */
      rc = sqlite3_step(pStmt);
      /* if we have a result set... */
      if( SQLITE_ROW == rc ){

  ".separator STRING      Change separator used by output mode and .import\n"
  ".show                  Show the current values for various settings\n"
  ".stats ON|OFF          Turn stats on or off\n"
  ".tables ?TABLE?        List names of tables\n"
  "                         If TABLE specified, only list tables matching\n"
  "                         LIKE pattern TABLE.\n"
  ".timeout MS            Try opening locked tables for MS milliseconds\n"
  ".vfsname ?AUX?         Print the name of the VFS stack\n"
  ".width NUM1 NUM2 ...   Set column widths for \"column\" mode\n"
;

static char zTimerHelp[] =
  ".timer ON|OFF          Turn the CPU timer measurement on or off\n"
;

      }else{
        zShellStatic = azArg[1];
        rc = sqlite3_exec(p->db,
          "SELECT sql FROM "
          "  (SELECT sql sql, type type, tbl_name tbl_name, name name"
          "     FROM sqlite_master UNION ALL"
          "   SELECT sql, type, tbl_name, name FROM sqlite_temp_master) "
          "WHERE lower(tbl_name) LIKE shellstatic()"
          "  AND type!='meta' AND sql NOTNULL "
          "ORDER BY substr(type,2,1), name",
          callback, &data, &zErrMsg);
        zShellStatic = 0;
      }
    }else{
      rc = sqlite3_exec(p->db,
         "SELECT sql FROM "

      { "benign_malloc_hooks",   SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS    },
      { "pending_byte",          SQLITE_TESTCTRL_PENDING_BYTE           },
      { "assert",                SQLITE_TESTCTRL_ASSERT                 },
      { "always",                SQLITE_TESTCTRL_ALWAYS                 },
      { "reserve",               SQLITE_TESTCTRL_RESERVE                },
      { "optimizations",         SQLITE_TESTCTRL_OPTIMIZATIONS          },
      { "iskeyword",             SQLITE_TESTCTRL_ISKEYWORD              },

      { "scratchmalloc",         SQLITE_TESTCTRL_SCRATCHMALLOC          },
    };
    int testctrl = -1;
    int rc = 0;
    int i, n;
    open_db(p);

          }
          break;

        /* sqlite3_test_control(int) */
        case SQLITE_TESTCTRL_PRNG_SAVE:           
        case SQLITE_TESTCTRL_PRNG_RESTORE:        
        case SQLITE_TESTCTRL_PRNG_RESET:

          if( nArg==2 ){
            rc = sqlite3_test_control(testctrl);
            printf("%d (0x%08x)\n", rc, rc);
          } else {
            fprintf(stderr,"Error: testctrl %s takes no options\n", azArg[1]);
          }
          break;

  if( HAS_TIMER && c=='t' && n>=5 && strncmp(azArg[0], "timer", n)==0
   && nArg==2
  ){
    enableTimer = booleanValue(azArg[1]);
  }else
  
  if( c=='v' && strncmp(azArg[0], "version", n)==0 ){
    printf("SQLite %s %s\n" /*extra-version-info*/,
        sqlite3_libversion(), sqlite3_sourceid());
  }else

  if( c=='v' && strncmp(azArg[0], "vfsname", n)==0 ){
    const char *zDbName = nArg==2 ? azArg[1] : "main";
    char *zVfsName = 0;
    if( p->db ){
      sqlite3_file_control(p->db, zDbName, SQLITE_FCNTL_VFSNAME, &zVfsName);
      if( zVfsName ){
        printf("%s\n", zVfsName);
        sqlite3_free(zVfsName);
      }
    }
  }else

  if( c=='w' && strncmp(azArg[0], "width", n)==0 && nArg>1 ){
    int j;
    assert( nArg<=ArraySize(azArg) );
    for(j=1; j<nArg && j<ArraySize(p->colWidth); j++){
      p->colWidth[j-1] = atoi(azArg[j]);
    }

#endif
  }else{
#ifndef SQLITE_OMIT_MEMORYDB
    data.zDbFilename = ":memory:";
#else
    data.zDbFilename = 0;
#endif
    /***** Begin Fossil Patch *****/
    {
      extern void fossil_open(const char **);
      fossil_open(&data.zDbFilename);
    }
    /***** End Fossil Patch *****/
  }
  if( i<argc ){

    /* Run commands received from standard input
    */
    if( stdin_is_interactive ){
      char *zHome;
      char *zHistory = 0;
      int nHistory;
      printf(
        "SQLite version %s %.19s\n" /*extra-version-info*/
        "Enter \".help\" for instructions\n"
        "Enter SQL statements terminated with a \";\"\n",
        sqlite3_libversion(), sqlite3_sourceid()
      );
      zHome = find_home_dir();
      if( zHome ){
        nHistory = strlen30(zHome) + 20;

/******************************************************************************
** This file is an amalgamation of many separate C source files from SQLite
** version 3.7.10.  By combining all the individual C code files into this 
** single large file, the entire code can be compiled as a single translation
** unit.  This allows many compilers to do optimizations that would not be
** possible if the files were compiled separately.  Performance improvements
** of 5% or more are commonly seen when SQLite is compiled as a single
** translation unit.
**
** This file is all you need to compile SQLite.  To use SQLite in other

#if defined(THREADSAFE)
# define SQLITE_THREADSAFE THREADSAFE
#else
# define SQLITE_THREADSAFE 1 /* IMP: R-07272-22309 */
#endif
#endif

/*
** Powersafe overwrite is on by default.  But can be turned off using
** the -DSQLITE_POWERSAFE_OVERWRITE=0 command-line option.
*/
#ifndef SQLITE_POWERSAFE_OVERWRITE
# define SQLITE_POWERSAFE_OVERWRITE 1
#endif

/*
** The SQLITE_DEFAULT_MEMSTATUS macro must be defined as either 0 or 1.
** It determines whether or not the features related to 
** SQLITE_CONFIG_MEMSTATUS are available by default or not. This value can
** be overridden at runtime using the sqlite3_config() API.
*/
#if !defined(SQLITE_DEFAULT_MEMSTATUS)

** string contains the date and time of the check-in (UTC) and an SHA1
** hash of the entire source tree.
**
** See also: [sqlite3_libversion()],
** [sqlite3_libversion_number()], [sqlite3_sourceid()],
** [sqlite_version()] and [sqlite_source_id()].
*/
#define SQLITE_VERSION        "3.7.10"
#define SQLITE_VERSION_NUMBER 3007010
#define SQLITE_SOURCE_ID      "2011-12-23 13:32:07 1f24ae716df6232de768e245ea990049deee3c22"

/*
** CAPI3REF: Run-Time Library Version Numbers
** KEYWORDS: sqlite3_version, sqlite3_sourceid
**
** These interfaces provide the same information as the [SQLITE_VERSION],
** [SQLITE_VERSION_NUMBER], and [SQLITE_SOURCE_ID] C preprocessor macros

** mean that writes of blocks that are nnn bytes in size and
** are aligned to an address which is an integer multiple of
** nnn are atomic.  The SQLITE_IOCAP_SAFE_APPEND value means
** that when data is appended to a file, the data is appended
** first then the size of the file is extended, never the other
** way around.  The SQLITE_IOCAP_SEQUENTIAL property means that
** information is written to disk in the same order as calls
** to xWrite().  The SQLITE_IOCAP_POWERSAFE_OVERWRITE property means that
** after reboot following a crash or power loss, the value of
** each byte in a file is a value that was actually written
** into that byte at some point.  In other words, a crash will
** not cause unwritten bytes of the file to change nor introduce 
** randomness into a file nor zero out parts of the file, and any byte of
** a file that are never written will not change values due to
** writes to nearby bytes.
*/
#define SQLITE_IOCAP_ATOMIC                 0x00000001
#define SQLITE_IOCAP_ATOMIC512              0x00000002
#define SQLITE_IOCAP_ATOMIC1K               0x00000004
#define SQLITE_IOCAP_ATOMIC2K               0x00000008
#define SQLITE_IOCAP_ATOMIC4K               0x00000010
#define SQLITE_IOCAP_ATOMIC8K               0x00000020
#define SQLITE_IOCAP_ATOMIC16K              0x00000040
#define SQLITE_IOCAP_ATOMIC32K              0x00000080
#define SQLITE_IOCAP_ATOMIC64K              0x00000100
#define SQLITE_IOCAP_SAFE_APPEND            0x00000200
#define SQLITE_IOCAP_SEQUENTIAL             0x00000400
#define SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN  0x00000800
#define SQLITE_IOCAP_POWERSAFE_OVERWRITE    0x00001000

/*
** CAPI3REF: File Locking Levels
**
** SQLite uses one of these integer values as the second
** argument to calls it makes to the xLock() and xUnlock() methods
** of an [sqlite3_io_methods] object.

** have write permission on the directory containing the database file want
** to read the database file, as the WAL and shared memory files must exist
** in order for the database to be readable.  The fourth parameter to
** [sqlite3_file_control()] for this opcode should be a pointer to an integer.
** That integer is 0 to disable persistent WAL mode or 1 to enable persistent
** WAL mode.  If the integer is -1, then it is overwritten with the current
** WAL persistence setting.
**
** ^The [SQLITE_FCNTL_POWERSAFE_OVERWRITE] opcode is used to set or query the
** persistent "powersafe-overwrite" or "PSOW" setting.  The PSOW setting
** determines the [SQLITE_IOCAP_POWERSAFE_OVERWRITE] bit of the
** xDeviceCharacteristics methods. The fourth parameter to
** [sqlite3_file_control()] for this opcode should be a pointer to an integer.
** That integer is 0 to disable zero-damage mode or 1 to enable zero-damage
** mode.  If the integer is -1, then it is overwritten with the current
** zero-damage mode setting.
**
** ^The [SQLITE_FCNTL_OVERWRITE] opcode is invoked by SQLite after opening
** a write transaction to indicate that, unless it is rolled back for some
** reason, the entire database file will be overwritten by the current 
** transaction. This is used by VACUUM operations.
**
** ^The [SQLITE_FCNTL_VFSNAME] opcode can be used to obtain the names of
** all [VFSes] in the VFS stack.  The names are of all VFS shims and the
** final bottom-level VFS are written into memory obtained from 
** [sqlite3_malloc()] and the result is stored in the char* variable
** that the fourth parameter of [sqlite3_file_control()] points to.
** The caller is responsible for freeing the memory when done.  As with
** all file-control actions, there is no guarantee that this will actually
** do anything.  Callers should initialize the char* variable to a NULL
** pointer in case this file-control is not implemented.  This file-control
** is intended for diagnostic use only.
*/
#define SQLITE_FCNTL_LOCKSTATE               1
#define SQLITE_GET_LOCKPROXYFILE             2
#define SQLITE_SET_LOCKPROXYFILE             3
#define SQLITE_LAST_ERRNO                    4
#define SQLITE_FCNTL_SIZE_HINT               5
#define SQLITE_FCNTL_CHUNK_SIZE              6
#define SQLITE_FCNTL_FILE_POINTER            7
#define SQLITE_FCNTL_SYNC_OMITTED            8
#define SQLITE_FCNTL_WIN32_AV_RETRY          9
#define SQLITE_FCNTL_PERSIST_WAL            10
#define SQLITE_FCNTL_OVERWRITE              11
#define SQLITE_FCNTL_VFSNAME                12
#define SQLITE_FCNTL_POWERSAFE_OVERWRITE    13

/*
** CAPI3REF: Mutex Handle
**
** The mutex module within SQLite defines [sqlite3_mutex] to be an
** abstract type for a mutex object.  The SQLite core never looks
** at the internal representation of an [sqlite3_mutex].  It only

** scratch memory beyond what is provided by this configuration option, then 
** [sqlite3_malloc()] will be used to obtain the memory needed.</dd>
**
** [[SQLITE_CONFIG_PAGECACHE]] <dt>SQLITE_CONFIG_PAGECACHE</dt>
** <dd> ^This option specifies a static memory buffer that SQLite can use for
** the database page cache with the default page cache implementation.  
** This configuration should not be used if an application-define page
** cache implementation is loaded using the SQLITE_CONFIG_PCACHE2 option.
** There are three arguments to this option: A pointer to 8-byte aligned
** memory, the size of each page buffer (sz), and the number of pages (N).
** The sz argument should be the size of the largest database page
** (a power of two between 512 and 32768) plus a little extra for each
** page header.  ^The page header size is 20 to 40 bytes depending on
** the host architecture.  ^It is harmless, apart from the wasted memory,
** to make sz a little too large.  The first

** [database connection].  The first argument is the
** size of each lookaside buffer slot and the second is the number of
** slots allocated to each database connection.)^  ^(This option sets the
** <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE]
** verb to [sqlite3_db_config()] can be used to change the lookaside
** configuration on individual connections.)^ </dd>
**
** [[SQLITE_CONFIG_PCACHE2]] <dt>SQLITE_CONFIG_PCACHE2</dt>
** <dd> ^(This option takes a single argument which is a pointer to
** an [sqlite3_pcache_methods2] object.  This object specifies the interface
** to a custom page cache implementation.)^  ^SQLite makes a copy of the
** object and uses it for page cache memory allocations.</dd>
**
** [[SQLITE_CONFIG_GETPCACHE2]] <dt>SQLITE_CONFIG_GETPCACHE2</dt>
** <dd> ^(This option takes a single argument which is a pointer to an
** [sqlite3_pcache_methods2] object.  SQLite copies of the current
** page cache implementation into that object.)^ </dd>
**
** [[SQLITE_CONFIG_LOG]] <dt>SQLITE_CONFIG_LOG</dt>
** <dd> ^The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a
** function with a call signature of void(*)(void*,int,const char*), 
** and a pointer to void. ^If the function pointer is not NULL, it is
** invoked by [sqlite3_log()] to process each logging event.  ^If the

** specified as part of [ATTACH] commands are interpreted as URIs, regardless
** of whether or not the [SQLITE_OPEN_URI] flag is set when the database
** connection is opened. If it is globally disabled, filenames are
** only interpreted as URIs if the SQLITE_OPEN_URI flag is set when the
** database connection is opened. By default, URI handling is globally
** disabled. The default value may be changed by compiling with the
** [SQLITE_USE_URI] symbol defined.
**
** [[SQLITE_CONFIG_PCACHE]] [[SQLITE_CONFIG_GETPCACHE]]
** <dt>SQLITE_CONFIG_PCACHE and SQLITE_CONFNIG_GETPCACHE
** <dd> These options are obsolete and should not be used by new code.
** They are retained for backwards compatibility but are now no-ops.
** </dl>
*/
#define SQLITE_CONFIG_SINGLETHREAD  1  /* nil */
#define SQLITE_CONFIG_MULTITHREAD   2  /* nil */
#define SQLITE_CONFIG_SERIALIZED    3  /* nil */
#define SQLITE_CONFIG_MALLOC        4  /* sqlite3_mem_methods* */
#define SQLITE_CONFIG_GETMALLOC     5  /* sqlite3_mem_methods* */
#define SQLITE_CONFIG_SCRATCH       6  /* void*, int sz, int N */
#define SQLITE_CONFIG_PAGECACHE     7  /* void*, int sz, int N */
#define SQLITE_CONFIG_HEAP          8  /* void*, int nByte, int min */
#define SQLITE_CONFIG_MEMSTATUS     9  /* boolean */
#define SQLITE_CONFIG_MUTEX        10  /* sqlite3_mutex_methods* */
#define SQLITE_CONFIG_GETMUTEX     11  /* sqlite3_mutex_methods* */
/* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */ 
#define SQLITE_CONFIG_LOOKASIDE    13  /* int int */
#define SQLITE_CONFIG_PCACHE       14  /* no-op */
#define SQLITE_CONFIG_GETPCACHE    15  /* no-op */
#define SQLITE_CONFIG_LOG          16  /* xFunc, void* */
#define SQLITE_CONFIG_URI          17  /* int */
#define SQLITE_CONFIG_PCACHE2      18  /* sqlite3_pcache_methods2* */
#define SQLITE_CONFIG_GETPCACHE2   19  /* sqlite3_pcache_methods2* */

/*
** CAPI3REF: Database Connection Configuration Options
**
** These constants are the available integer configuration options that
** can be passed as the second argument to the [sqlite3_db_config()] interface.
**

  int flags,              /* Flags */
  const char *zVfs        /* Name of VFS module to use */
);

/*
** CAPI3REF: Obtain Values For URI Parameters
**
** These are utility routines, useful to VFS implementations, that check
** to see if a database file was a URI that contained a specific query 
** parameter, and if so obtains the value of that query parameter.
**
** If F is the filename pointer passed into the xOpen() method of a VFS
** implementation and P is the name of the query parameter, then
** sqlite3_uri_parameter(F,P) returns the value of the P
** parameter if it exists or a NULL pointer if P does not appear as a 
** query parameter on F.  If P is a query parameter of F
** has no explicit value, then sqlite3_uri_parameter(F,P) returns
** a pointer to an empty string.
**
** The sqlite3_uri_boolean(F,P,B) routine assumes that P is a boolean
** parameter and returns true (1) or false (0) according to the value
** of P.  The value of P is true if it is "yes" or "true" or "on" or 
** a non-zero number and is false otherwise.  If P is not a query parameter
** on F then sqlite3_uri_boolean(F,P,B) returns (B!=0).
**
** The sqlite3_uri_int64(F,P,D) routine converts the value of P into a
** 64-bit signed integer and returns that integer, or D if P does not
** exist.  If the value of P is something other than an integer, then
** zero is returned.
** 
** If F is a NULL pointer, then sqlite3_uri_parameter(F,P) returns NULL and
** sqlite3_uri_boolean(F,P,B) returns B.  If F is not a NULL pointer and
** is not a pathname pointer that SQLite passed into the xOpen VFS method,
** then the behavior of this routine is undefined and probably undesirable.
*/
SQLITE_API const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam);
SQLITE_API int sqlite3_uri_boolean(const char *zFile, const char *zParam, int bDefault);
SQLITE_API sqlite3_int64 sqlite3_uri_int64(const char*, const char*, sqlite3_int64);


/*
** CAPI3REF: Error Codes And Messages
**
** ^The sqlite3_errcode() interface returns the numeric [result code] or
** [extended result code] for the most recent failed sqlite3_* API call

** database.  ^The [ATTACH] and [DETACH] statements also cause
** sqlite3_stmt_readonly() to return true since, while those statements
** change the configuration of a database connection, they do not make 
** changes to the content of the database files on disk.
*/
SQLITE_API int sqlite3_stmt_readonly(sqlite3_stmt *pStmt);

/*
** CAPI3REF: Determine If A Prepared Statement Has Been Reset
**
** ^The sqlite3_stmt_busy(S) interface returns true (non-zero) if the
** [prepared statement] S has been stepped at least once using 
** [sqlite3_step(S)] but has not run to completion and/or has not 
** been reset using [sqlite3_reset(S)].  ^The sqlite3_stmt_busy(S)
** interface returns false if S is a NULL pointer.  If S is not a 
** NULL pointer and is not a pointer to a valid [prepared statement]
** object, then the behavior is undefined and probably undesirable.
**
** This interface can be used in combination [sqlite3_next_stmt()]
** to locate all prepared statements associated with a database 
** connection that are in need of being reset.  This can be used,
** for example, in diagnostic routines to search for prepared 
** statements that are holding a transaction open.
*/
SQLITE_API int sqlite3_stmt_busy(sqlite3_stmt*);

/*
** CAPI3REF: Dynamically Typed Value Object
** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value}
**
** SQLite uses the sqlite3_value object to represent all values
** that can be stored in a database table. SQLite uses dynamic typing
** for the values it stores.  ^Values stored in sqlite3_value objects

** returned by sqlite3_db_handle is the same [database connection]
** that was the first argument
** to the [sqlite3_prepare_v2()] call (or its variants) that was used to
** create the statement in the first place.
*/
SQLITE_API sqlite3 *sqlite3_db_handle(sqlite3_stmt*);

/*
** CAPI3REF: Return The Filename For A Database Connection
**
** ^The sqlite3_db_filename(D,N) interface returns a pointer to a filename
** associated with database N of connection D.  ^The main database file
** has the name "main".  If there is no attached database N on the database
** connection D, or if database N is a temporary or in-memory database, then
** a NULL pointer is returned.
**
** ^The filename returned by this function is the output of the
** xFullPathname method of the [VFS].  ^In other words, the filename
** will be an absolute pathname, even if the filename used
** to open the database originally was a URI or relative pathname.
*/
SQLITE_API const char *sqlite3_db_filename(sqlite3 *db, const char *zDbName);

/*
** CAPI3REF: Find the next prepared statement
**
** ^This interface returns a pointer to the next [prepared statement] after
** pStmt associated with the [database connection] pDb.  ^If pStmt is NULL
** then this interface returns a pointer to the first prepared statement
** associated with the database connection pDb.  ^If no prepared statement

** then the commit is converted into a rollback.
**
** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions
** return the P argument from the previous call of the same function
** on the same [database connection] D, or NULL for
** the first call for each function on D.
**
** The commit and rollback hook callbacks are not reentrant.
** The callback implementation must not do anything that will modify
** the database connection that invoked the callback.  Any actions
** to modify the database connection must be deferred until after the
** completion of the [sqlite3_step()] call that triggered the commit
** or rollback hook in the first place.
** Note that running any other SQL statements, including SELECT statements,
** or merely calling [sqlite3_prepare_v2()] and [sqlite3_step()] will modify
** the database connections for the meaning of "modify" in this paragraph.
**
** ^Registering a NULL function disables the callback.
**
** ^When the commit hook callback routine returns zero, the [COMMIT]
** operation is allowed to continue normally.  ^If the commit hook
** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK].
** ^The rollback hook is invoked on a rollback that results from a commit

** of heap memory by deallocating non-essential memory allocations
** held by the database library.   Memory used to cache database
** pages to improve performance is an example of non-essential memory.
** ^sqlite3_release_memory() returns the number of bytes actually freed,
** which might be more or less than the amount requested.
** ^The sqlite3_release_memory() routine is a no-op returning zero
** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT].
**
** See also: [sqlite3_db_release_memory()]
*/
SQLITE_API int sqlite3_release_memory(int);

/*
** CAPI3REF: Free Memory Used By A Database Connection
**
** ^The sqlite3_db_shrink(D) interface attempts to free as much heap
** memory as possible from database connection D. Unlike the
** [sqlite3_release_memory()] interface, this interface is effect even
** when then [SQLITE_ENABLE_MEMORY_MANAGEMENT] compile-time option is
** omitted.
**
** See also: [sqlite3_release_memory()]
*/
SQLITE_API int sqlite3_db_release_memory(sqlite3*);

/*
** CAPI3REF: Impose A Limit On Heap Size
**
** ^The sqlite3_soft_heap_limit64() interface sets and/or queries the
** soft limit on the amount of heap memory that may be allocated by SQLite.
** ^SQLite strives to keep heap memory utilization below the soft heap
** limit by reducing the number of pages held in the page cache
** as heap memory usages approaches the limit.
** ^The soft heap limit is "soft" because even though SQLite strives to stay
** below the limit, it will exceed the limit rather than generate
** an [SQLITE_NOMEM] error.  In other words, the soft heap limit 
** is advisory only.
**
** ^The return value from sqlite3_soft_heap_limit64() is the size of
** the soft heap limit prior to the call, or negative in the case of an
** error.  ^If the argument N is negative
** then no change is made to the soft heap limit.  Hence, the current
** size of the soft heap limit can be determined by invoking
** sqlite3_soft_heap_limit64() with a negative argument.
**
** ^If the argument N is zero then the soft heap limit is disabled.
**
** ^(The soft heap limit is not enforced in the current implementation
** if one or more of following conditions are true:
**
** <ul>
** <li> The soft heap limit is set to zero.
** <li> Memory accounting is disabled using a combination of the
**      [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],...) start-time option and
**      the [SQLITE_DEFAULT_MEMSTATUS] compile-time option.
** <li> An alternative page cache implementation is specified using
**      [sqlite3_config]([SQLITE_CONFIG_PCACHE2],...).
** <li> The page cache allocates from its own memory pool supplied
**      by [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],...) rather than
**      from the heap.
** </ul>)^
**
** Beginning with SQLite version 3.7.3, the soft heap limit is enforced
** regardless of whether or not the [SQLITE_ENABLE_MEMORY_MANAGEMENT]

#define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS     10
#define SQLITE_TESTCTRL_PENDING_BYTE            11
#define SQLITE_TESTCTRL_ASSERT                  12
#define SQLITE_TESTCTRL_ALWAYS                  13
#define SQLITE_TESTCTRL_RESERVE                 14
#define SQLITE_TESTCTRL_OPTIMIZATIONS           15
#define SQLITE_TESTCTRL_ISKEYWORD               16

#define SQLITE_TESTCTRL_SCRATCHMALLOC           17
#define SQLITE_TESTCTRL_LOCALTIME_FAULT         18
#define SQLITE_TESTCTRL_EXPLAIN_STMT            19
#define SQLITE_TESTCTRL_LAST                    19

/*
** CAPI3REF: SQLite Runtime Status
**
** ^This interface is used to retrieve runtime status information
** about the performance of SQLite, and optionally to reset various

**
** The sqlite3_pcache type is opaque.  It is implemented by
** the pluggable module.  The SQLite core has no knowledge of
** its size or internal structure and never deals with the
** sqlite3_pcache object except by holding and passing pointers
** to the object.
**
** See [sqlite3_pcache_methods2] for additional information.
*/
typedef struct sqlite3_pcache sqlite3_pcache;

/*
** CAPI3REF: Custom Page Cache Object
**
** The sqlite3_pcache_page object represents a single page in the
** page cache.  The page cache will allocate instances of this
** object.  Various methods of the page cache use pointers to instances
** of this object as parameters or as their return value.
**
** See [sqlite3_pcache_methods2] for additional information.
*/
typedef struct sqlite3_pcache_page sqlite3_pcache_page;
struct sqlite3_pcache_page {
  void *pBuf;        /* The content of the page */
  void *pExtra;      /* Extra information associated with the page */
};

/*
** CAPI3REF: Application Defined Page Cache.
** KEYWORDS: {page cache}
**
** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE2], ...) interface can
** register an alternative page cache implementation by passing in an 
** instance of the sqlite3_pcache_methods2 structure.)^
** In many applications, most of the heap memory allocated by 
** SQLite is used for the page cache.
** By implementing a 
** custom page cache using this API, an application can better control
** the amount of memory consumed by SQLite, the way in which 
** that memory is allocated and released, and the policies used to 
** determine exactly which parts of a database file are cached and for 
** how long.
**
** The alternative page cache mechanism is an
** extreme measure that is only needed by the most demanding applications.
** The built-in page cache is recommended for most uses.
**
** ^(The contents of the sqlite3_pcache_methods2 structure are copied to an
** internal buffer by SQLite within the call to [sqlite3_config].  Hence
** the application may discard the parameter after the call to
** [sqlite3_config()] returns.)^
**
** [[the xInit() page cache method]]
** ^(The xInit() method is called once for each effective 
** call to [sqlite3_initialize()])^

** ^SQLite will never invoke xInit() more than once without an intervening
** call to xShutdown().
**
** [[the xCreate() page cache methods]]
** ^SQLite invokes the xCreate() method to construct a new cache instance.
** SQLite will typically create one cache instance for each open database file,
** though this is not guaranteed. ^The
** parameter parameter, szPage, is the size in bytes of the pages that must
** be allocated by the cache.  ^szPage will always a power of two.  ^The
** second parameter szExtra is a number of bytes of extra storage 
** associated with each page cache entry.  ^The szExtra parameter will
** a number less than 250.  SQLite will use the
** extra szExtra bytes on each page to store metadata about the underlying
** database page on disk.  The value passed into szExtra depends
** on the SQLite version, the target platform, and how SQLite was compiled.



** ^The third argument to xCreate(), bPurgeable, is true if the cache being
** created will be used to cache database pages of a file stored on disk, or
** false if it is used for an in-memory database. The cache implementation
** does not have to do anything special based with the value of bPurgeable;
** it is purely advisory.  ^On a cache where bPurgeable is false, SQLite will
** never invoke xUnpin() except to deliberately delete a page.
** ^In other words, calls to xUnpin() on a cache with bPurgeable set to
** false will always have the "discard" flag set to true.  
** ^Hence, a cache created with bPurgeable false will

**
** [[the xPagecount() page cache methods]]
** The xPagecount() method must return the number of pages currently
** stored in the cache, both pinned and unpinned.
** 
** [[the xFetch() page cache methods]]
** The xFetch() method locates a page in the cache and returns a pointer to 
** an sqlite3_pcache_page object associated with that page, or a NULL pointer.
** The pBuf element of the returned sqlite3_pcache_page object will be a
** pointer to a buffer of szPage bytes used to store the content of a 
** single database page.  The pExtra element of sqlite3_pcache_page will be
** a pointer to the szExtra bytes of extra storage that SQLite has requested
** for each entry in the page cache.
**
** The page to be fetched is determined by the key. ^The minimum key value
** is 1.  After it has been retrieved using xFetch, the page is considered
** to be "pinned".
**
** If the requested page is already in the page cache, then the page cache
** implementation must return a pointer to the page buffer with its content
** intact.  If the requested page is not already in the cache, then the
** cache implementation should use the value of the createFlag
** parameter to help it determined what action to take:
**

**
** [[the xDestroy() page cache method]]
** ^The xDestroy() method is used to delete a cache allocated by xCreate().
** All resources associated with the specified cache should be freed. ^After
** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*]
** handle invalid, and will not use it with any other sqlite3_pcache_methods
** functions.
**
** [[the xShrink() page cache method]]
** ^SQLite invokes the xShrink() method when it wants the page cache to
** free up as much of heap memory as possible.  The page cache implementation
** is not obligated to free any memory, but well-behaved implementions should
** do their best.
*/
typedef struct sqlite3_pcache_methods2 sqlite3_pcache_methods2;
struct sqlite3_pcache_methods2 {
  int iVersion;
  void *pArg;
  int (*xInit)(void*);
  void (*xShutdown)(void*);
  sqlite3_pcache *(*xCreate)(int szPage, int szExtra, int bPurgeable);
  void (*xCachesize)(sqlite3_pcache*, int nCachesize);
  int (*xPagecount)(sqlite3_pcache*);
  sqlite3_pcache_page *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag);
  void (*xUnpin)(sqlite3_pcache*, sqlite3_pcache_page*, int discard);
  void (*xRekey)(sqlite3_pcache*, sqlite3_pcache_page*, 
      unsigned oldKey, unsigned newKey);
  void (*xTruncate)(sqlite3_pcache*, unsigned iLimit);
  void (*xDestroy)(sqlite3_pcache*);
  void (*xShrink)(sqlite3_pcache*);
};

/*
** This is the obsolete pcache_methods object that has now been replaced
** by sqlite3_pcache_methods2.  This object is not used by SQLite.  It is
** retained in the header file for backwards compatibility only.
*/
typedef struct sqlite3_pcache_methods sqlite3_pcache_methods;
struct sqlite3_pcache_methods {
  void *pArg;
  int (*xInit)(void*);
  void (*xShutdown)(void*);
  sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable);
  void (*xCachesize)(sqlite3_pcache*, int nCachesize);
  int (*xPagecount)(sqlite3_pcache*);
  void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag);
  void (*xUnpin)(sqlite3_pcache*, void*, int discard);
  void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey);
  void (*xTruncate)(sqlite3_pcache*, unsigned iLimit);
  void (*xDestroy)(sqlite3_pcache*);
};


/*
** CAPI3REF: Online Backup Object
**
** The sqlite3_backup object records state information about an ongoing
** online backup operation.  ^The sqlite3_backup object is created by
** a call to [sqlite3_backup_init()] and is destroyed by a call to

** The "file format" number is an integer that is incremented whenever
** the VDBE-level file format changes.  The following macros define the
** the default file format for new databases and the maximum file format
** that the library can read.
*/
#define SQLITE_MAX_FILE_FORMAT 4
#ifndef SQLITE_DEFAULT_FILE_FORMAT
# define SQLITE_DEFAULT_FILE_FORMAT 4
#endif

/*
** Determine whether triggers are recursive by default.  This can be
** changed at run-time using a pragma.
*/
#ifndef SQLITE_DEFAULT_RECURSIVE_TRIGGERS

** A sub-routine used to implement a trigger program.
*/
struct SubProgram {
  VdbeOp *aOp;                  /* Array of opcodes for sub-program */
  int nOp;                      /* Elements in aOp[] */
  int nMem;                     /* Number of memory cells required */
  int nCsr;                     /* Number of cursors required */
  int nOnce;                    /* Number of OP_Once instructions */
  void *token;                  /* id that may be used to recursive triggers */
  SubProgram *pNext;            /* Next sub-program already visited */
};

/*
** A smaller version of VdbeOp used for the VdbeAddOpList() function because
** it takes up less space.

#define OPFLG_OUT2_PRERELEASE 0x0002  /* out2-prerelease: */
#define OPFLG_IN1             0x0004  /* in1:   P1 is an input */
#define OPFLG_IN2             0x0008  /* in2:   P2 is an input */
#define OPFLG_IN3             0x0010  /* in3:   P3 is an input */
#define OPFLG_OUT2            0x0020  /* out2:  P2 is an output */
#define OPFLG_OUT3            0x0040  /* out3:  P3 is an output */
#define OPFLG_INITIALIZER {\
/*   0 */ 0x00, 0x01, 0x01, 0x04, 0x04, 0x10, 0x00, 0x02,\
/*   8 */ 0x02, 0x02, 0x02, 0x02, 0x02, 0x00, 0x24, 0x24,\
/*  16 */ 0x00, 0x00, 0x00, 0x24, 0x04, 0x05, 0x04, 0x00,\
/*  24 */ 0x00, 0x01, 0x01, 0x05, 0x05, 0x00, 0x00, 0x00,\
/*  32 */ 0x02, 0x00, 0x00, 0x00, 0x02, 0x10, 0x00, 0x00,\
/*  40 */ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x11, 0x11,\
/*  48 */ 0x11, 0x11, 0x08, 0x11, 0x11, 0x11, 0x11, 0x02,\
/*  56 */ 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,\
/*  64 */ 0x00, 0x02, 0x00, 0x01, 0x4c, 0x4c, 0x01, 0x01,\
/*  72 */ 0x01, 0x05, 0x05, 0x15, 0x15, 0x15, 0x15, 0x15,\
/*  80 */ 0x15, 0x01, 0x4c, 0x4c, 0x4c, 0x4c, 0x4c, 0x4c,\

SQLITE_PRIVATE int sqlite3PagerReadFileheader(Pager*, int, unsigned char*);

/* Functions used to configure a Pager object. */
SQLITE_PRIVATE void sqlite3PagerSetBusyhandler(Pager*, int(*)(void *), void *);
SQLITE_PRIVATE int sqlite3PagerSetPagesize(Pager*, u32*, int);
SQLITE_PRIVATE int sqlite3PagerMaxPageCount(Pager*, int);
SQLITE_PRIVATE void sqlite3PagerSetCachesize(Pager*, int);
SQLITE_PRIVATE void sqlite3PagerShrink(Pager*);
SQLITE_PRIVATE void sqlite3PagerSetSafetyLevel(Pager*,int,int,int);
SQLITE_PRIVATE int sqlite3PagerLockingMode(Pager *, int);
SQLITE_PRIVATE int sqlite3PagerSetJournalMode(Pager *, int);
SQLITE_PRIVATE int sqlite3PagerGetJournalMode(Pager*);
SQLITE_PRIVATE int sqlite3PagerOkToChangeJournalMode(Pager*);
SQLITE_PRIVATE i64 sqlite3PagerJournalSizeLimit(Pager *, i64);
SQLITE_PRIVATE sqlite3_backup **sqlite3PagerBackupPtr(Pager*);

typedef struct PCache PCache;

/*
** Every page in the cache is controlled by an instance of the following
** structure.
*/
struct PgHdr {
  sqlite3_pcache_page *pPage;    /* Pcache object page handle */
  void *pData;                   /* Page data */
  void *pExtra;                  /* Extra content */
  PgHdr *pDirty;                 /* Transient list of dirty pages */
  Pgno pgno;                     /* Page number for this page */
  Pager *pPager;                 /* The pager this page is part of */
#ifdef SQLITE_CHECK_PAGES
  u32 pageHash;                  /* Hash of page content */
#endif

** of the suggested cache-sizes.
*/
SQLITE_PRIVATE void sqlite3PcacheSetCachesize(PCache *, int);
#ifdef SQLITE_TEST
SQLITE_PRIVATE int sqlite3PcacheGetCachesize(PCache *);
#endif

/* Free up as much memory as possible from the page cache */
SQLITE_PRIVATE void sqlite3PcacheShrink(PCache*);

#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
/* Try to return memory used by the pcache module to the main memory heap */
SQLITE_PRIVATE int sqlite3PcacheReleaseMemory(int);
#endif

#ifdef SQLITE_TEST
SQLITE_PRIVATE void sqlite3PcacheStats(int*,int*,int*,int*);

#  define SQLITE_OS_OS2 0
# endif
#else
# ifndef SQLITE_OS_WIN
#  define SQLITE_OS_WIN 0
# endif
#endif












/*
** Define the maximum size of a temporary filename
*/
#if SQLITE_OS_WIN
# include <windows.h>
# define SQLITE_TEMPNAME_SIZE (MAX_PATH+50)

# include <os2.h>
# include <uconv.h>
# define SQLITE_TEMPNAME_SIZE (CCHMAXPATHCOMP)
#else
# define SQLITE_TEMPNAME_SIZE 200
#endif

/*
** Determine if we are dealing with Windows NT.
*/
#if defined(_WIN32_WINNT)
# define SQLITE_OS_WINNT 1
#else
# define SQLITE_OS_WINNT 0
#endif

/*
** Determine if we are dealing with WindowsCE - which has a much
** reduced API.
*/
#if defined(_WIN32_WCE)
# define SQLITE_OS_WINCE 1
#else
# define SQLITE_OS_WINCE 0
#endif

/* If the SET_FULLSYNC macro is not defined above, then make it
** a no-op
*/
#ifndef SET_FULLSYNC
# define SET_FULLSYNC(x,y)
#endif

** If both CollSeq.xCmp and CollSeq.xCmp16 are NULL, it means that the
** collating sequence is undefined.  Indices built on an undefined
** collating sequence may not be read or written.
*/
struct CollSeq {
  char *zName;          /* Name of the collating sequence, UTF-8 encoded */
  u8 enc;               /* Text encoding handled by xCmp() */

  void *pUser;          /* First argument to xCmp() */
  int (*xCmp)(void*,int, const void*, int, const void*);
  void (*xDel)(void*);  /* Destructor for pUser */
};









/*
** A sort order can be either ASC or DESC.
*/
#define SQLITE_SO_ASC       0  /* Sort in ascending order */
#define SQLITE_SO_DESC      1  /* Sort in ascending order */

/*

**
** This structure holds a record that has already been disassembled
** into its constituent fields.
*/
struct UnpackedRecord {
  KeyInfo *pKeyInfo;  /* Collation and sort-order information */
  u16 nField;         /* Number of entries in apMem[] */
  u8 flags;           /* Boolean settings.  UNPACKED_... below */
  i64 rowid;          /* Used by UNPACKED_PREFIX_SEARCH */
  Mem *aMem;          /* Values */
};

/*
** Allowed values of UnpackedRecord.flags
*/



#define UNPACKED_INCRKEY       0x01  /* Make this key an epsilon larger */
#define UNPACKED_PREFIX_MATCH  0x02  /* A prefix match is considered OK */
#define UNPACKED_PREFIX_SEARCH 0x04  /* Ignore final (rowid) field */

/*
** Each SQL index is represented in memory by an
** instance of the following structure.
**
** The columns of the table that are to be indexed are described
** by the aiColumn[] field of this structure.  For example, suppose

#define EP_VarSelect  0x0020  /* pSelect is correlated, not constant */
#define EP_DblQuoted  0x0040  /* token.z was originally in "..." */
#define EP_InfixFunc  0x0080  /* True for an infix function: LIKE, GLOB, etc */
#define EP_ExpCollate 0x0100  /* Collating sequence specified explicitly */
#define EP_FixedDest  0x0200  /* Result needed in a specific register */
#define EP_IntValue   0x0400  /* Integer value contained in u.iValue */
#define EP_xIsSelect  0x0800  /* x.pSelect is valid (otherwise x.pList is) */
#define EP_Hint       0x1000  /* Optimizer hint. Not required for correctness */
#define EP_Reduced    0x2000  /* Expr struct is EXPR_REDUCEDSIZE bytes only */
#define EP_TokenOnly  0x4000  /* Expr struct is EXPR_TOKENONLYSIZE bytes only */
#define EP_Static     0x8000  /* Held in memory not obtained from malloc() */

/*
** The following are the meanings of bits in the Expr.flags2 field.
*/
#define EP2_MallocedToken  0x0001  /* Need to sqlite3DbFree() Expr.zToken */
#define EP2_Irreducible    0x0002  /* Cannot EXPRDUP_REDUCE this Expr */

  int iECursor;          /* VDBE Cursor associated with this ExprList */
  struct ExprList_item {
    Expr *pExpr;           /* The list of expressions */
    char *zName;           /* Token associated with this expression */
    char *zSpan;           /* Original text of the expression */
    u8 sortOrder;          /* 1 for DESC or 0 for ASC */
    u8 done;               /* A flag to indicate when processing is finished */
    u16 iOrderByCol;       /* For ORDER BY, column number in result set */
    u16 iAlias;            /* Index into Parse.aAlias[] for zName */
  } *a;                  /* One entry for each expression */
};

/*
** An instance of this structure is used by the parser to record both
** the parse tree for an expression and the span of input text for an

  double nSelectRow;     /* Estimated number of result rows */
};

/*
** Allowed values for Select.selFlags.  The "SF" prefix stands for
** "Select Flag".
*/
#define SF_Distinct        0x01  /* Output should be DISTINCT */
#define SF_Resolved        0x02  /* Identifiers have been resolved */
#define SF_Aggregate       0x04  /* Contains aggregate functions */
#define SF_UsesEphemeral   0x08  /* Uses the OpenEphemeral opcode */
#define SF_Expanded        0x10  /* sqlite3SelectExpand() called on this */
#define SF_HasTypeInfo     0x20  /* FROM subqueries have Table metadata */
#define SF_UseSorter       0x40  /* Sort using a sorter */


/*
** The results of a select can be distributed in several ways.  The
** "SRT" prefix means "SELECT Result Type".
*/
#define SRT_Union        1  /* Store result as keys in an index */

*/
struct Parse {
  sqlite3 *db;         /* The main database structure */
  int rc;              /* Return code from execution */
  char *zErrMsg;       /* An error message */
  Vdbe *pVdbe;         /* An engine for executing database bytecode */
  u8 colNamesSet;      /* TRUE after OP_ColumnName has been issued to pVdbe */

  u8 checkSchema;      /* Causes schema cookie check after an error */
  u8 nested;           /* Number of nested calls to the parser/code generator */

  u8 nTempReg;         /* Number of temporary registers in aTempReg[] */
  u8 nTempInUse;       /* Number of aTempReg[] currently checked out */
  int aTempReg[8];     /* Holding area for temporary registers */
  int nRangeReg;       /* Size of the temporary register block */
  int iRangeReg;       /* First register in temporary register block */
  int nErr;            /* Number of errors seen */
  int nTab;            /* Number of previously allocated VDBE cursors */
  int nMem;            /* Number of memory cells used so far */
  int nSet;            /* Number of sets used so far */
  int nOnce;           /* Number of OP_Once instructions so far */
  int ckBase;          /* Base register of data during check constraints */
  int iCacheLevel;     /* ColCache valid when aColCache[].iLevel<=iCacheLevel */
  int iCacheCnt;       /* Counter used to generate aColCache[].lru values */
  u8 nColCache;        /* Number of entries in aColCache[] */
  u8 iColCache;        /* Next entry in aColCache[] to replace */
  struct yColCache {
    int iTable;           /* Table cursor number */
    int iColumn;          /* Table column number */
    u8 tempReg;           /* iReg is a temp register that needs to be freed */
    int iLevel;           /* Nesting level */
    int iReg;             /* Reg with value of this column. 0 means none. */
    int lru;              /* Least recently used entry has the smallest value */

  ** each recursion */

  int nVar;            /* Number of '?' variables seen in the SQL so far */
  int nzVar;           /* Number of available slots in azVar[] */
  char **azVar;        /* Pointers to names of parameters */
  Vdbe *pReprepare;    /* VM being reprepared (sqlite3Reprepare()) */
  int nAlias;          /* Number of aliased result set columns */

  int *aAlias;         /* Register used to hold aliased result */
  u8 explain;          /* True if the EXPLAIN flag is found on the query */
  Token sNameToken;    /* Token with unqualified schema object name */
  Token sLastToken;    /* The last token parsed */
  const char *zTail;   /* All SQL text past the last semicolon parsed */
  Table *pNewTable;    /* A table being constructed by CREATE TABLE */
  Trigger *pNewTrigger;     /* Trigger under construct by a CREATE TRIGGER */

  int bFullMutex;                   /* True to enable full mutexing */
  int bOpenUri;                     /* True to interpret filenames as URIs */
  int mxStrlen;                     /* Maximum string length */
  int szLookaside;                  /* Default lookaside buffer size */
  int nLookaside;                   /* Default lookaside buffer count */
  sqlite3_mem_methods m;            /* Low-level memory allocation interface */
  sqlite3_mutex_methods mutex;      /* Low-level mutex interface */
  sqlite3_pcache_methods2 pcache2;  /* Low-level page-cache interface */
  void *pHeap;                      /* Heap storage space */
  int nHeap;                        /* Size of pHeap[] */
  int mnReq, mxReq;                 /* Min and max heap requests sizes */
  void *pScratch;                   /* Scratch memory */
  int szScratch;                    /* Size of each scratch buffer */
  int nScratch;                     /* Number of scratch buffers */
  void *pPage;                      /* Page cache memory */

SQLITE_PRIVATE char *sqlite3MAppendf(sqlite3*,char*,const char*,...);
#if defined(SQLITE_TEST) || defined(SQLITE_DEBUG)
SQLITE_PRIVATE   void sqlite3DebugPrintf(const char*, ...);
#endif
#if defined(SQLITE_TEST)
SQLITE_PRIVATE   void *sqlite3TestTextToPtr(const char*);
#endif

/* Output formatting for SQLITE_TESTCTRL_EXPLAIN */
#if defined(SQLITE_ENABLE_TREE_EXPLAIN)
SQLITE_PRIVATE   void sqlite3ExplainBegin(Vdbe*);
SQLITE_PRIVATE   void sqlite3ExplainPrintf(Vdbe*, const char*, ...);
SQLITE_PRIVATE   void sqlite3ExplainNL(Vdbe*);
SQLITE_PRIVATE   void sqlite3ExplainPush(Vdbe*);
SQLITE_PRIVATE   void sqlite3ExplainPop(Vdbe*);
SQLITE_PRIVATE   void sqlite3ExplainFinish(Vdbe*);
SQLITE_PRIVATE   void sqlite3ExplainSelect(Vdbe*, Select*);
SQLITE_PRIVATE   void sqlite3ExplainExpr(Vdbe*, Expr*);
SQLITE_PRIVATE   void sqlite3ExplainExprList(Vdbe*, ExprList*);
SQLITE_PRIVATE   const char *sqlite3VdbeExplanation(Vdbe*);
#else
# define sqlite3ExplainBegin(X)
# define sqlite3ExplainSelect(A,B)
# define sqlite3ExplainExpr(A,B)
# define sqlite3ExplainExprList(A,B)
# define sqlite3ExplainFinish(X)
# define sqlite3VdbeExplanation(X) 0
#endif


SQLITE_PRIVATE void sqlite3SetString(char **, sqlite3*, const char*, ...);
SQLITE_PRIVATE void sqlite3ErrorMsg(Parse*, const char*, ...);
SQLITE_PRIVATE int sqlite3Dequote(char*);
SQLITE_PRIVATE int sqlite3KeywordCode(const unsigned char*, int);
SQLITE_PRIVATE int sqlite3RunParser(Parse*, const char*, char **);
SQLITE_PRIVATE void sqlite3FinishCoding(Parse*);
SQLITE_PRIVATE int sqlite3GetTempReg(Parse*);
SQLITE_PRIVATE void sqlite3ReleaseTempReg(Parse*,int);
SQLITE_PRIVATE int sqlite3GetTempRange(Parse*,int);
SQLITE_PRIVATE void sqlite3ReleaseTempRange(Parse*,int,int);
SQLITE_PRIVATE void sqlite3ClearTempRegCache(Parse*);
SQLITE_PRIVATE Expr *sqlite3ExprAlloc(sqlite3*,int,const Token*,int);
SQLITE_PRIVATE Expr *sqlite3Expr(sqlite3*,int,const char*);
SQLITE_PRIVATE void sqlite3ExprAttachSubtrees(sqlite3*,Expr*,Expr*,Expr*);
SQLITE_PRIVATE Expr *sqlite3PExpr(Parse*, int, Expr*, Expr*, const Token*);
SQLITE_PRIVATE Expr *sqlite3ExprAnd(sqlite3*,Expr*, Expr*);
SQLITE_PRIVATE Expr *sqlite3ExprFunction(Parse*,ExprList*, Token*);
SQLITE_PRIVATE void sqlite3ExprAssignVarNumber(Parse*, Expr*);

SQLITE_PRIVATE void sqlite3AddCheckConstraint(Parse*, Expr*);
SQLITE_PRIVATE void sqlite3AddColumnType(Parse*,Token*);
SQLITE_PRIVATE void sqlite3AddDefaultValue(Parse*,ExprSpan*);
SQLITE_PRIVATE void sqlite3AddCollateType(Parse*, Token*);
SQLITE_PRIVATE void sqlite3EndTable(Parse*,Token*,Token*,Select*);
SQLITE_PRIVATE int sqlite3ParseUri(const char*,const char*,unsigned int*,
                    sqlite3_vfs**,char**,char **);
SQLITE_PRIVATE int sqlite3CodeOnce(Parse *);

SQLITE_PRIVATE Bitvec *sqlite3BitvecCreate(u32);
SQLITE_PRIVATE int sqlite3BitvecTest(Bitvec*, u32);
SQLITE_PRIVATE int sqlite3BitvecSet(Bitvec*, u32);
SQLITE_PRIVATE void sqlite3BitvecClear(Bitvec*, u32, void*);
SQLITE_PRIVATE void sqlite3BitvecDestroy(Bitvec*);
SQLITE_PRIVATE u32 sqlite3BitvecSize(Bitvec*);

  FuncDestructor *pDestructor
);
SQLITE_PRIVATE int sqlite3ApiExit(sqlite3 *db, int);
SQLITE_PRIVATE int sqlite3OpenTempDatabase(Parse *);

SQLITE_PRIVATE void sqlite3StrAccumInit(StrAccum*, char*, int, int);
SQLITE_PRIVATE void sqlite3StrAccumAppend(StrAccum*,const char*,int);
SQLITE_PRIVATE void sqlite3AppendSpace(StrAccum*,int);
SQLITE_PRIVATE char *sqlite3StrAccumFinish(StrAccum*);
SQLITE_PRIVATE void sqlite3StrAccumReset(StrAccum*);
SQLITE_PRIVATE void sqlite3SelectDestInit(SelectDest*,int,int);
SQLITE_PRIVATE Expr *sqlite3CreateColumnExpr(sqlite3 *, SrcList *, int, int);

SQLITE_PRIVATE void sqlite3BackupRestart(sqlite3_backup *);
SQLITE_PRIVATE void sqlite3BackupUpdate(sqlite3_backup *, Pgno, const u8 *);

   SQLITE_THREADSAFE==1,      /* bFullMutex */
   SQLITE_USE_URI,            /* bOpenUri */
   0x7ffffffe,                /* mxStrlen */
   128,                       /* szLookaside */
   500,                       /* nLookaside */
   {0,0,0,0,0,0,0,0},         /* m */
   {0,0,0,0,0,0,0,0,0},       /* mutex */
   {0,0,0,0,0,0,0,0,0,0,0,0,0},/* pcache2 */
   (void*)0,                  /* pHeap */
   0,                         /* nHeap */
   0, 0,                      /* mnHeap, mxHeap */
   (void*)0,                  /* pScratch */
   0,                         /* szScratch */
   0,                         /* nScratch */
   (void*)0,                  /* pPage */

** Boolean values
*/
typedef unsigned char Bool;

/* Opaque type used by code in vdbesort.c */
typedef struct VdbeSorter VdbeSorter;

/* Opaque type used by the explainer */
typedef struct Explain Explain;

/*
** A cursor is a pointer into a single BTree within a database file.
** The cursor can seek to a BTree entry with a particular key, or
** loop over all entries of the Btree.  You can also insert new BTree
** entries or retrieve the key or data from the entry that the cursor
** is currently pointing to.
** 

struct VdbeFrame {
  Vdbe *v;                /* VM this frame belongs to */
  int pc;                 /* Program Counter in parent (calling) frame */
  Op *aOp;                /* Program instructions for parent frame */
  int nOp;                /* Size of aOp array */
  Mem *aMem;              /* Array of memory cells for parent frame */
  int nMem;               /* Number of entries in aMem */
  u8 *aOnceFlag;          /* Array of OP_Once flags for parent frame */
  int nOnceFlag;          /* Number of entries in aOnceFlag */
  VdbeCursor **apCsr;     /* Array of Vdbe cursors for parent frame */
  u16 nCursor;            /* Number of entries in apCsr */
  void *token;            /* Copy of SubProgram.token */
  int nChildMem;          /* Number of memory cells for child frame */
  int nChildCsr;          /* Number of cursors for child frame */
  i64 lastRowid;          /* Last insert rowid (sqlite3.lastRowid) */
  int nChange;            /* Statement changes (Vdbe.nChanges)     */

  VdbeFunc *pVdbeFunc;  /* Auxilary data, if created. */
  Mem s;                /* The return value is stored here */
  Mem *pMem;            /* Memory cell used to store aggregate context */
  int isError;          /* Error code returned by the function. */
  CollSeq *pColl;       /* Collating sequence */
};

/*
** An Explain object accumulates indented output which is helpful
** in describing recursive data structures.
*/
struct Explain {
  Vdbe *pVdbe;       /* Attach the explanation to this Vdbe */
  StrAccum str;      /* The string being accumulated */
  int nIndent;       /* Number of elements in aIndent */
  u16 aIndent[100];  /* Levels of indentation */
  char zBase[100];   /* Initial space */
};

/*
** An instance of the virtual machine.  This structure contains the complete
** state of the virtual machine.
**
** The "sqlite3_stmt" structure pointer that is returned by sqlite3_prepare()
** is really a pointer to an instance of this structure.
**

  i64 nFkConstraint;      /* Number of imm. FK constraints this VM */
  i64 nStmtDefCons;       /* Number of def. constraints when stmt started */
  char *zSql;             /* Text of the SQL statement that generated this */
  void *pFree;            /* Free this when deleting the vdbe */
#ifdef SQLITE_DEBUG
  FILE *trace;            /* Write an execution trace here, if not NULL */
#endif
#ifdef SQLITE_ENABLE_TREE_EXPLAIN
  Explain *pExplain;      /* The explainer */
  char *zExplain;         /* Explanation of data structures */
#endif
  VdbeFrame *pFrame;      /* Parent frame */
  VdbeFrame *pDelFrame;   /* List of frame objects to free on VM reset */
  int nFrame;             /* Number of frames in pFrame list */
  u32 expmask;            /* Binding to these vars invalidates VM */
  SubProgram *pProgram;   /* Linked list of all sub-programs used by VM */
  int nOnceFlag;          /* Size of array aOnceFlag[] */
  u8 *aOnceFlag;          /* Flags for OP_Once */
};

/*
** The following are allowed values for Vdbe.magic
*/
#define VDBE_MAGIC_INIT     0x26bceaa5    /* Building a VDBE program */
#define VDBE_MAGIC_RUN      0xbdf20da3    /* VDBE is ready to execute */

** from within OsOpen()), but some third-party implementations may.
** So we test the effects of a malloc() failing and the sqlite3OsXXX()
** function returning SQLITE_IOERR_NOMEM using the DO_OS_MALLOC_TEST macro.
**
** The following functions are instrumented for malloc() failure 
** testing:
**

**     sqlite3OsRead()
**     sqlite3OsWrite()
**     sqlite3OsSync()
**     sqlite3OsFileSize()
**     sqlite3OsLock()
**     sqlite3OsCheckReservedLock()
**     sqlite3OsFileControl()
**     sqlite3OsShmMap()
**     sqlite3OsOpen()
**     sqlite3OsDelete()
**     sqlite3OsAccess()
**     sqlite3OsFullPathname()
**
*/
#if defined(SQLITE_TEST)
SQLITE_API int sqlite3_memdebug_vfs_oom_test = 1;
  #define DO_OS_MALLOC_TEST(x)                                       \
  if (sqlite3_memdebug_vfs_oom_test && (!x || !sqlite3IsMemJournal(x))) {  \
    void *pTstAlloc = sqlite3Malloc(10);                             \

  return id->pMethods->xUnlock(id, lockType);
}
SQLITE_PRIVATE int sqlite3OsCheckReservedLock(sqlite3_file *id, int *pResOut){
  DO_OS_MALLOC_TEST(id);
  return id->pMethods->xCheckReservedLock(id, pResOut);
}
SQLITE_PRIVATE int sqlite3OsFileControl(sqlite3_file *id, int op, void *pArg){
  DO_OS_MALLOC_TEST(id);
  return id->pMethods->xFileControl(id, op, pArg);
}
SQLITE_PRIVATE int sqlite3OsSectorSize(sqlite3_file *id){
  int (*xSectorSize)(sqlite3_file*) = id->pMethods->xSectorSize;
  return (xSectorSize ? xSectorSize(id) : SQLITE_DEFAULT_SECTOR_SIZE);
}
SQLITE_PRIVATE int sqlite3OsDeviceCharacteristics(sqlite3_file *id){

SQLITE_PRIVATE int sqlite3OsShmMap(
  sqlite3_file *id,               /* Database file handle */
  int iPage,
  int pgsz,
  int bExtend,                    /* True to extend file if necessary */
  void volatile **pp              /* OUT: Pointer to mapping */
){
  DO_OS_MALLOC_TEST(id);
  return id->pMethods->xShmMap(id, iPage, pgsz, bExtend, pp);
}

/*
** The next group of routines are convenience wrappers around the
** VFS methods.
*/

  ** SQLITE_OPEN_FULLMUTEX or SQLITE_OPEN_SHAREDCACHE) are blocked before
  ** reaching the VFS. */
  rc = pVfs->xOpen(pVfs, zPath, pFile, flags & 0x87f7f, pFlagsOut);
  assert( rc==SQLITE_OK || pFile->pMethods==0 );
  return rc;
}
SQLITE_PRIVATE int sqlite3OsDelete(sqlite3_vfs *pVfs, const char *zPath, int dirSync){
  DO_OS_MALLOC_TEST(0);
  return pVfs->xDelete(pVfs, zPath, dirSync);
}
SQLITE_PRIVATE int sqlite3OsAccess(
  sqlite3_vfs *pVfs, 
  const char *zPath, 
  int flags, 
  int *pResOut
){
  DO_OS_MALLOC_TEST(0);
  return pVfs->xAccess(pVfs, zPath, flags, pResOut);
}
SQLITE_PRIVATE int sqlite3OsFullPathname(
  sqlite3_vfs *pVfs, 
  const char *zPath, 
  int nPathOut, 
  char *zPathOut
){
  DO_OS_MALLOC_TEST(0);
  zPathOut[0] = 0;
  return pVfs->xFullPathname(pVfs, zPath, nPathOut, zPathOut);
}
#ifndef SQLITE_OMIT_LOAD_EXTENSION
SQLITE_PRIVATE void *sqlite3OsDlOpen(sqlite3_vfs *pVfs, const char *zPath){
  return pVfs->xDlOpen(pVfs, zPath);
}

/*
** This version of the memory allocator is the default.  It is
** used when no other memory allocator is specified using compile-time
** macros.
*/
#ifdef SQLITE_SYSTEM_MALLOC

/*
** Windows systems have malloc_usable_size() but it is called _msize()
*/
#if !defined(HAVE_MALLOC_USABLE_SIZE) && SQLITE_OS_WIN
# define HAVE_MALLOC_USABLE_SIZE 1
# define malloc_usable_size _msize
#endif

#if defined(__APPLE__)

/*
** Use the zone allocator available on apple products
*/
#include <sys/sysctl.h>
#include <malloc/malloc.h>
#include <libkern/OSAtomic.h>
static malloc_zone_t* _sqliteZone_;
#define SQLITE_MALLOC(x) malloc_zone_malloc(_sqliteZone_, (x))
#define SQLITE_FREE(x) malloc_zone_free(_sqliteZone_, (x));
#define SQLITE_REALLOC(x,y) malloc_zone_realloc(_sqliteZone_, (x), (y))
#define SQLITE_MALLOCSIZE(x) \
        (_sqliteZone_ ? _sqliteZone_->size(_sqliteZone_,x) : malloc_size(x))

#else /* if not __APPLE__ */

/*
** Use standard C library malloc and free on non-Apple systems.
*/
#define SQLITE_MALLOC(x)    malloc(x)
#define SQLITE_FREE(x)      free(x)
#define SQLITE_REALLOC(x,y) realloc((x),(y))

#ifdef HAVE_MALLOC_USABLE_SIZE
#include <malloc.h>
#define SQLITE_MALLOCSIZE(x) malloc_usable_size(x)
#else
#undef SQLITE_MALLOCSIZE
#endif

#endif /* __APPLE__ or not __APPLE__ */

/*
** Like malloc(), but remember the size of the allocation
** so that we can find it later using sqlite3MemSize().
**
** For this low-level routine, we are guaranteed that nByte>0 because
** cases of nByte<=0 will be intercepted and dealt with by higher level
** routines.
*/
static void *sqlite3MemMalloc(int nByte){
#ifdef SQLITE_MALLOCSIZE
  void *p = SQLITE_MALLOC( nByte );
  if( p==0 ){
    testcase( sqlite3GlobalConfig.xLog!=0 );
    sqlite3_log(SQLITE_NOMEM, "failed to allocate %u bytes of memory", nByte);
  }
  return p;
#else
  sqlite3_int64 *p;
  assert( nByte>0 );
  nByte = ROUND8(nByte);
  p = SQLITE_MALLOC( nByte+8 );
  if( p ){
    p[0] = nByte;
    p++;
  }else{
    testcase( sqlite3GlobalConfig.xLog!=0 );
    sqlite3_log(SQLITE_NOMEM, "failed to allocate %u bytes of memory", nByte);
  }
  return (void *)p;
#endif
}

/*
** Like free() but works for allocations obtained from sqlite3MemMalloc()
** or sqlite3MemRealloc().
**
** For this low-level routine, we already know that pPrior!=0 since
** cases where pPrior==0 will have been intecepted and dealt with
** by higher-level routines.
*/
static void sqlite3MemFree(void *pPrior){
#ifdef SQLITE_MALLOCSIZE
  SQLITE_FREE(pPrior);
#else
  sqlite3_int64 *p = (sqlite3_int64*)pPrior;
  assert( pPrior!=0 );
  p--;
  SQLITE_FREE(p);
#endif
}

/*
** Report the allocated size of a prior return from xMalloc()
** or xRealloc().
*/
static int sqlite3MemSize(void *pPrior){
#ifdef SQLITE_MALLOCSIZE
  return pPrior ? (int)SQLITE_MALLOCSIZE(pPrior) : 0;
#else
  sqlite3_int64 *p;
  if( pPrior==0 ) return 0;
  p = (sqlite3_int64*)pPrior;
  p--;
  return (int)p[0];
#endif
}

/*
** Like realloc().  Resize an allocation previously obtained from
** sqlite3MemMalloc().
**
** For this low-level interface, we know that pPrior!=0.  Cases where
** pPrior==0 while have been intercepted by higher-level routine and
** redirected to xMalloc.  Similarly, we know that nByte>0 becauses
** cases where nByte<=0 will have been intercepted by higher-level
** routines and redirected to xFree.
*/
static void *sqlite3MemRealloc(void *pPrior, int nByte){
#ifdef SQLITE_MALLOCSIZE
  void *p = SQLITE_REALLOC(pPrior, nByte);
  if( p==0 ){
    testcase( sqlite3GlobalConfig.xLog!=0 );
    sqlite3_log(SQLITE_NOMEM,
      "failed memory resize %u to %u bytes",
      SQLITE_MALLOCSIZE(pPrior), nByte);
  }
  return p;
#else
  sqlite3_int64 *p = (sqlite3_int64*)pPrior;
  assert( pPrior!=0 && nByte>0 );
  assert( nByte==ROUND8(nByte) ); /* EV: R-46199-30249 */
  p--;
  p = SQLITE_REALLOC(p, nByte+8 );
  if( p ){
    p[0] = nByte;
    p++;
  }else{
    testcase( sqlite3GlobalConfig.xLog!=0 );
    sqlite3_log(SQLITE_NOMEM,
      "failed memory resize %u to %u bytes",
      sqlite3MemSize(pPrior), nByte);
  }
  return (void*)p;
#endif
}

/*
** Round up a request size to the next valid allocation size.
*/
static int sqlite3MemRoundup(int n){
  return ROUND8(n);
}

/*
** Initialize this module.
*/
static int sqlite3MemInit(void *NotUsed){
#if defined(__APPLE__)
  int cpuCount;
  size_t len;
  if( _sqliteZone_ ){
    return SQLITE_OK;
  }
  len = sizeof(cpuCount);
  /* One usually wants to use hw.acctivecpu for MT decisions, but not here */
  sysctlbyname("hw.ncpu", &cpuCount, &len, NULL, 0);
  if( cpuCount>1 ){
    /* defer MT decisions to system malloc */
    _sqliteZone_ = malloc_default_zone();
  }else{
    /* only 1 core, use our own zone to contention over global locks, 
    ** e.g. we have our own dedicated locks */
    bool success;		
    malloc_zone_t* newzone = malloc_create_zone(4096, 0);
    malloc_set_zone_name(newzone, "Sqlite_Heap");
    do{
      success = OSAtomicCompareAndSwapPtrBarrier(NULL, newzone, 
                                 (void * volatile *)&_sqliteZone_);
    }while(!_sqliteZone_);
    if( !success ){	
      /* somebody registered a zone first */
      malloc_destroy_zone(newzone);
    }
  }
#endif
  UNUSED_PARAMETER(NotUsed);
  return SQLITE_OK;
}

/*
** Deinitialize this module.
*/

** Set the soft heap-size limit for the library. Passing a zero or 
** negative value indicates no limit.
*/
SQLITE_API sqlite3_int64 sqlite3_soft_heap_limit64(sqlite3_int64 n){
  sqlite3_int64 priorLimit;
  sqlite3_int64 excess;
#ifndef SQLITE_OMIT_AUTOINIT
  int rc = sqlite3_initialize();
  if( rc ) return -1;
#endif
  sqlite3_mutex_enter(mem0.mutex);
  priorLimit = mem0.alarmThreshold;
  sqlite3_mutex_leave(mem0.mutex);
  if( n<0 ) return priorLimit;
  if( n>0 ){
    sqlite3MemoryAlarm(softHeapLimitEnforcer, 0, n);

  return (char)digit;
}
#endif /* SQLITE_OMIT_FLOATING_POINT */

/*
** Append N space characters to the given string buffer.
*/
SQLITE_PRIVATE void sqlite3AppendSpace(StrAccum *pAccum, int N){
  static const char zSpaces[] = "                             ";
  while( N>=(int)sizeof(zSpaces)-1 ){
    sqlite3StrAccumAppend(pAccum, zSpaces, sizeof(zSpaces)-1);
    N -= sizeof(zSpaces)-1;
  }
  if( N>0 ){
    sqlite3StrAccumAppend(pAccum, zSpaces, N);

    ** "length" characters long.  The field width is "width".  Do
    ** the output.
    */
    if( !flag_leftjustify ){
      register int nspace;
      nspace = width-length;
      if( nspace>0 ){
        sqlite3AppendSpace(pAccum, nspace);
      }
    }
    if( length>0 ){
      sqlite3StrAccumAppend(pAccum, bufpt, length);
    }
    if( flag_leftjustify ){
      register int nspace;
      nspace = width-length;
      if( nspace>0 ){
        sqlite3AppendSpace(pAccum, nspace);
      }
    }
    sqlite3_free(zExtra);
  }/* End for loop over the format string */
} /* End of function */

/*

** do the suffix shortening regardless of URI parameter.
**
** Examples:
**
**     test.db-journal    =>   test.nal
**     test.db-wal        =>   test.wal
**     test.db-shm        =>   test.shm
**     test.db-mj7f3319fa =>   test.9fa
*/
SQLITE_PRIVATE void sqlite3FileSuffix3(const char *zBaseFilename, char *z){
#if SQLITE_ENABLE_8_3_NAMES<2

  if( sqlite3_uri_boolean(zBaseFilename, "8_3_names") )

#endif
  {
    int i, sz;
    sz = sqlite3Strlen30(z);
    for(i=sz-1; i>0 && z[i]!='/' && z[i]!='.'; i--){}
    if( z[i]=='.' && ALWAYS(sz>i+4) ) memmove(&z[i+1], &z[sz-3], 4);
  }
}
#endif

/************** End of util.c ************************************************/
/************** Begin file hash.c ********************************************/
/*

#include <unistd.h>
/* #include <time.h> */
#include <sys/time.h>
#include <errno.h>
#ifndef SQLITE_OMIT_WAL
#include <sys/mman.h>
#endif
#ifndef MISSING_STATVFS
#include <sys/statvfs.h>
#endif


#if SQLITE_ENABLE_LOCKING_STYLE
# include <sys/ioctl.h>
# if OS_VXWORKS
#  include <semaphore.h>
#  include <limits.h>
# else

/*
** The unixFile structure is subclass of sqlite3_file specific to the unix
** VFS implementations.
*/
typedef struct unixFile unixFile;
struct unixFile {
  sqlite3_io_methods const *pMethod;  /* Always the first entry */
  sqlite3_vfs *pVfs;                  /* The VFS that created this unixFile */
  unixInodeInfo *pInode;              /* Info about locks on this inode */
  int h;                              /* The file descriptor */
  unsigned char eFileLock;            /* The type of lock held on this fd */
  unsigned char ctrlFlags;            /* Behavioral bits.  UNIXFILE_* flags */
  unsigned char szSector;             /* Sectorsize/512 */
  int lastErrno;                      /* The unix errno from last I/O error */
  void *lockingContext;               /* Locking style specific state */
  UnixUnusedFd *pUnused;              /* Pre-allocated UnixUnusedFd */
  const char *zPath;                  /* Name of the file */
  unixShm *pShm;                      /* Shared memory segment information */
  int szChunk;                        /* Configured by FCNTL_CHUNK_SIZE */
#if SQLITE_ENABLE_LOCKING_STYLE

#define UNIXFILE_RDONLY      0x02     /* Connection is read only */
#define UNIXFILE_PERSIST_WAL 0x04     /* Persistent WAL mode */
#ifndef SQLITE_DISABLE_DIRSYNC
# define UNIXFILE_DIRSYNC    0x08     /* Directory sync needed */
#else
# define UNIXFILE_DIRSYNC    0x00
#endif
#define UNIXFILE_PSOW        0x10     /* SQLITE_IOCAP_POWERSAFE_OVERWRITE */

/*
** Include code that is common to all os_*.c files
*/
/************** Include os_common.h in the middle of os_unix.c ***************/
/************** Begin file os_common.h ***************************************/
/*

#define osFallocate ((int(*)(int,off_t,off_t))aSyscall[15].pCurrent)

  { "unlink",       (sqlite3_syscall_ptr)unlink,           0 },
#define osUnlink    ((int(*)(const char*))aSyscall[16].pCurrent)

  { "openDirectory",    (sqlite3_syscall_ptr)openDirectory,      0 },
#define osOpenDirectory ((int(*)(const char*,int*))aSyscall[17].pCurrent)

  { "mkdir",        (sqlite3_syscall_ptr)mkdir,           0 },
#define osMkdir     ((int(*)(const char*,mode_t))aSyscall[18].pCurrent)

  { "rmdir",        (sqlite3_syscall_ptr)rmdir,           0 },
#define osRmdir     ((int(*)(const char*))aSyscall[19].pCurrent)

#if defined(MISSING_STATVFS)
  { "statvfs",      (sqlite3_syscall_ptr)0,               0 },
#define osStatvfs   ((int(*)(const char*,void*))aSyscall[20].pCurrent)
#else
  { "statvfs",      (sqlite3_syscall_ptr)statvfs,         0 },
#define osStatvfs   ((int(*)(const char*,struct statvfs*))aSyscall[20].pCurrent)
#endif

}; /* End of the overrideable system calls */

/*
** This is the xSetSystemCall() method of sqlite3_vfs for all of the
** "unix" VFSes.  Return SQLITE_OK opon successfully updating the
** system call pointer, or SQLITE_NOTFOUND if there is no configurable

/******************* End of the no-op lock implementation *********************
******************************************************************************/

/******************************************************************************
************************* Begin dot-file Locking ******************************
**
** The dotfile locking implementation uses the existance of separate lock
** files (really a directory) to control access to the database.  This works
** on just about every filesystem imaginable.  But there are serious downsides:
**
**    (1)  There is zero concurrency.  A single reader blocks all other
**         connections from reading or writing the database.
**
**    (2)  An application crash or power loss can leave stale lock files
**         sitting around that need to be cleared manually.
**
** Nevertheless, a dotlock is an appropriate locking mode for use if no
** other locking strategy is available.
**
** Dotfile locking works by creating a subdirectory in the same directory as
** the database and with the same name but with a ".lock" extension added.
** The existance of a lock directory implies an EXCLUSIVE lock.  All other
** lock types (SHARED, RESERVED, PENDING) are mapped into EXCLUSIVE.
*/

/*
** The file suffix added to the data base filename in order to create the
** lock directory.
*/
#define DOTLOCK_SUFFIX ".lock"

/*
** This routine checks if there is a RESERVED lock held on the specified
** file by this or any other process. If such a lock is held, set *pResOut
** to a non-zero value otherwise *pResOut is set to zero.  The return value

** routine to lower a locking level.
**
** With dotfile locking, we really only support state (4): EXCLUSIVE.
** But we track the other locking levels internally.
*/
static int dotlockLock(sqlite3_file *id, int eFileLock) {
  unixFile *pFile = (unixFile*)id;

  char *zLockFile = (char *)pFile->lockingContext;
  int rc = SQLITE_OK;


  /* If we have any lock, then the lock file already exists.  All we have
  ** to do is adjust our internal record of the lock level.
  */
  if( pFile->eFileLock > NO_LOCK ){
    pFile->eFileLock = eFileLock;
    /* Always update the timestamp on the old file */
#ifdef HAVE_UTIME
    utime(zLockFile, NULL);
#else
    utimes(zLockFile, NULL);
#endif
    return SQLITE_OK;
  }
  
  /* grab an exclusive lock */
  rc = osMkdir(zLockFile, 0777);
  if( rc<0 ){
    /* failed to open/create the lock directory */
    int tErrno = errno;
    if( EEXIST == tErrno ){
      rc = SQLITE_BUSY;
    } else {
      rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_LOCK);
      if( IS_LOCK_ERROR(rc) ){
        pFile->lastErrno = tErrno;
      }
    }
    return rc;
  } 

  
  /* got it, set the type and return ok */
  pFile->eFileLock = eFileLock;
  return rc;
}

/*
** Lower the locking level on file descriptor pFile to eFileLock.  eFileLock
** must be either NO_LOCK or SHARED_LOCK.
**
** If the locking level of the file descriptor is already at or below
** the requested locking level, this routine is a no-op.
**
** When the locking level reaches NO_LOCK, delete the lock file.
*/
static int dotlockUnlock(sqlite3_file *id, int eFileLock) {
  unixFile *pFile = (unixFile*)id;
  char *zLockFile = (char *)pFile->lockingContext;
  int rc;

  assert( pFile );
  OSTRACE(("UNLOCK  %d %d was %d pid=%d (dotlock)\n", pFile->h, eFileLock,
	   pFile->eFileLock, getpid()));
  assert( eFileLock<=SHARED_LOCK );
  
  /* no-op if possible */

  if( eFileLock==SHARED_LOCK ){
    pFile->eFileLock = SHARED_LOCK;
    return SQLITE_OK;
  }
  
  /* To fully unlock the database, delete the lock file */
  assert( eFileLock==NO_LOCK );
  rc = osRmdir(zLockFile);
  if( rc<0 && errno==ENOTDIR ) rc = osUnlink(zLockFile);
  if( rc<0 ){
    int tErrno = errno;
    rc = 0;
    if( ENOENT != tErrno ){
      rc = SQLITE_IOERR_UNLOCK;
    }
    if( IS_LOCK_ERROR(rc) ){
      pFile->lastErrno = tErrno;
    }
    return rc; 

** See tickets #2741 and #2681.
**
** To avoid stomping the errno value on a failed read the lastErrno value
** is set before returning.
*/
static int seekAndRead(unixFile *id, sqlite3_int64 offset, void *pBuf, int cnt){
  int got;
  int prior = 0;
#if (!defined(USE_PREAD) && !defined(USE_PREAD64))
  i64 newOffset;
#endif
  TIMER_START;
  do{
#if defined(USE_PREAD)
    got = osPread(id->h, pBuf, cnt, offset);
    SimulateIOError( got = -1 );
#elif defined(USE_PREAD64)
    got = osPread64(id->h, pBuf, cnt, offset);
    SimulateIOError( got = -1 );
#else
    newOffset = lseek(id->h, offset, SEEK_SET);
    SimulateIOError( newOffset-- );
    if( newOffset!=offset ){
      if( newOffset == -1 ){
        ((unixFile*)id)->lastErrno = errno;
      }else{
        ((unixFile*)id)->lastErrno = 0;			
      }
      return -1;
    }
    got = osRead(id->h, pBuf, cnt);
#endif

    if( got==cnt ) break;
    if( got<0 ){
      if( errno==EINTR ){ got = 1; continue; }
      prior = 0;
      ((unixFile*)id)->lastErrno = errno;
      break;
    }else if( got>0 ){
      cnt -= got;
      offset += got;
      prior += got;
      pBuf = (void*)(got + (char*)pBuf);
    }
  }while( got>0 );
  TIMER_END;
  OSTRACE(("READ    %-3d %5d %7lld %llu\n",
            id->h, got+prior, offset-prior, TIMER_ELAPSED));
  return got+prior;
}

/*
** Read data from a file into a buffer.  Return SQLITE_OK if all
** bytes were read successfully and SQLITE_IOERR if anything goes
** wrong.
*/

      }
#endif
    }
  }

  return SQLITE_OK;
}

/*
** If *pArg is inititially negative then this is a query.  Set *pArg to
** 1 or 0 depending on whether or not bit mask of pFile->ctrlFlags is set.
**
** If *pArg is 0 or 1, then clear or set the mask bit of pFile->ctrlFlags.
*/
static void unixModeBit(unixFile *pFile, unsigned char mask, int *pArg){
  if( *pArg<0 ){
    *pArg = (pFile->ctrlFlags & mask)!=0;
  }else if( (*pArg)==0 ){
    pFile->ctrlFlags &= ~mask;
  }else{
    pFile->ctrlFlags |= mask;
  }
}

/*
** Information and control of an open file handle.
*/
static int unixFileControl(sqlite3_file *id, int op, void *pArg){
  unixFile *pFile = (unixFile*)id;
  switch( op ){

      int rc;
      SimulateIOErrorBenign(1);
      rc = fcntlSizeHint(pFile, *(i64 *)pArg);
      SimulateIOErrorBenign(0);
      return rc;
    }
    case SQLITE_FCNTL_PERSIST_WAL: {


      unixModeBit(pFile, UNIXFILE_PERSIST_WAL, (int*)pArg);
      return SQLITE_OK;
    }
    case SQLITE_FCNTL_POWERSAFE_OVERWRITE: {
      unixModeBit(pFile, UNIXFILE_PSOW, (int*)pArg);
      return SQLITE_OK;

    }
    case SQLITE_FCNTL_VFSNAME: {
      *(char**)pArg = sqlite3_mprintf("%s", pFile->pVfs->zName);
      return SQLITE_OK;
    }
#ifndef NDEBUG
    /* The pager calls this method to signal that it has done
    ** a rollback and that the database is therefore unchanged and
    ** it hence it is OK for the transaction change counter to be
    ** unchanged.

** larger for some devices.
**
** SQLite code assumes this function cannot fail. It also assumes that
** if two files are created in the same file-system directory (i.e.
** a database and its journal file) that the sector size will be the
** same for both.
*/
static int unixSectorSize(sqlite3_file *pFile){
  unixFile *p = (unixFile*)pFile;
  if( p->szSector==0 ){
#ifdef MISSING_STATVFS
    p->szSector = SQLITE_DEFAULT_SECTOR_SIZE/512;
#else
    struct statvfs x;
    int sz;
    memset(&x, 0, sizeof(x));
    osStatvfs(p->zPath, &x);
    sz = (int)x.f_frsize;
    if( sz<512 || sz>65536 || (sz&(sz-1))!=0 ){
      sz = SQLITE_DEFAULT_SECTOR_SIZE;
    }
    p->szSector = sz/512;
#endif
  }
  return p->szSector*512;
}

/*
** Return the device characteristics for the file.
**
** This VFS is set up to return SQLITE_IOCAP_POWERSAFE_OVERWRITE by default.
** However, that choice is contraversial since technically the underlying
** file system does not always provide powersafe overwrites.  (In other
** words, after a power-loss event, parts of the file that were never
** written might end up being altered.)  However, non-PSOW behavior is very,
** very rare.  And asserting PSOW makes a large reduction in the amount
** of required I/O for journaling, since a lot of padding is eliminated.
**  Hence, while POWERSAFE_OVERWRITE is on by default, there is a file-control
** available to turn it off and URI query parameter available to turn it off.
*/
static int unixDeviceCharacteristics(sqlite3_file *id){
  unixFile *p = (unixFile*)id;
  if( p->ctrlFlags & UNIXFILE_PSOW ){
    return SQLITE_IOCAP_POWERSAFE_OVERWRITE;
  }else{
    return 0;
  }
}

#ifndef SQLITE_OMIT_WAL


/*
** Object used to represent an shared memory buffer.  

    pShmNode->mutex = sqlite3_mutex_alloc(SQLITE_MUTEX_FAST);
    if( pShmNode->mutex==0 ){
      rc = SQLITE_NOMEM;
      goto shm_open_err;
    }

    if( pInode->bProcessLock==0 ){

      int openFlags = O_RDWR | O_CREAT;
      if( sqlite3_uri_boolean(pDbFd->zPath, "readonly_shm", 0) ){

        openFlags = O_RDONLY;
        pShmNode->isReadonly = 1;
      }
      pShmNode->h = robust_open(zShmFilename, openFlags, (sStat.st_mode&0777));
      if( pShmNode->h<0 ){
        if( pShmNode->h<0 ){
          rc = unixLogError(SQLITE_CANTOPEN_BKPT, "open", zShmFilename);

#endif

  /* No locking occurs in temporary files */
  assert( zFilename!=0 || noLock );

  OSTRACE(("OPEN    %-3d %s\n", h, zFilename));
  pNew->h = h;
  pNew->pVfs = pVfs;
  pNew->zPath = zFilename;
  pNew->ctrlFlags = 0;
  if( sqlite3_uri_boolean(zFilename, "psow", SQLITE_POWERSAFE_OVERWRITE) ){
    pNew->ctrlFlags |= UNIXFILE_PSOW;
  }
  if( memcmp(pVfs->zName,"unix-excl",10)==0 ){


    pNew->ctrlFlags |= UNIXFILE_EXCL;
  }
  if( isReadOnly ){
    pNew->ctrlFlags |= UNIXFILE_RDONLY;
  }
  if( syncDir ){
    pNew->ctrlFlags |= UNIXFILE_DIRSYNC;
  }

    **   "<path to db>-walNN"
    **
    ** where NN is a decimal number. The NN naming schemes are 
    ** used by the test_multiplex.c module.
    */
    nDb = sqlite3Strlen30(zPath) - 1; 
#ifdef SQLITE_ENABLE_8_3_NAMES
    while( nDb>0 && sqlite3Isalnum(zPath[nDb]) ) nDb--;
    if( nDb==0 || zPath[nDb]!='-' ) return SQLITE_OK;
#else
    while( zPath[nDb]!='-' ){
      assert( nDb>0 );
      assert( zPath[nDb]!='\n' );
      nDb--;
    }

  buf[0] = lockPath[0];
  for( i=1; i<len; i++ ){
    if( lockPath[i] == '/' && (i - start > 0) ){
      /* only mkdir if leaf dir != "." or "/" or ".." */
      if( i-start>2 || (i-start==1 && buf[start] != '.' && buf[start] != '/') 
         || (i-start==2 && buf[start] != '.' && buf[start+1] != '.') ){
        buf[i]='\0';
        if( osMkdir(buf, SQLITE_DEFAULT_PROXYDIR_PERMISSIONS) ){
          int err=errno;
          if( err!=EEXIST ) {
            OSTRACE(("CREATELOCKPATH  FAILED creating %s, "
                     "'%s' proxy lock path=%s pid=%d\n",
                     buf, strerror(err), lockPath, getpid()));
            return err;
          }

    UNIXVFS("unix-proxy",    proxyIoFinder ),
#endif
  };
  unsigned int i;          /* Loop counter */

  /* Double-check that the aSyscall[] array has been constructed
  ** correctly.  See ticket [bb3a86e890c8e96ab] */
  assert( ArraySize(aSyscall)==21 );

  /* Register all VFSes defined in the aVfs[] array */
  for(i=0; i<(sizeof(aVfs)/sizeof(sqlite3_vfs)); i++){
    sqlite3_vfs_register(&aVfs[i], i==0);
  }
  return SQLITE_OK; 
}

**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
******************************************************************************
**
** This file contains code that is specific to Windows.
*/
#if SQLITE_OS_WIN               /* This file is used for Windows only */






























#ifdef __CYGWIN__
# include <sys/cygwin.h>
#endif








/*
** Include code that is common to all os_*.c files
*/
/************** Include os_common.h in the middle of os_win.c ****************/
/************** Begin file os_common.h ***************************************/
/*
** 2004 May 22

#endif /* !defined(_OS_COMMON_H_) */

/************** End of os_common.h *******************************************/
/************** Continuing where we left off in os_win.c *********************/

/*
** Some Microsoft compilers lack this definition.
*/
#ifndef INVALID_FILE_ATTRIBUTES
# define INVALID_FILE_ATTRIBUTES ((DWORD)-1) 
#endif










/* Forward references */
typedef struct winShm winShm;           /* A connection to shared-memory */
typedef struct winShmNode winShmNode;   /* A region of shared-memory */

/*
** WinCE lacks native support for file locking so we have to fake it
** with some code of our own.

typedef struct winFile winFile;
struct winFile {
  const sqlite3_io_methods *pMethod; /*** Must be first ***/
  sqlite3_vfs *pVfs;      /* The VFS used to open this file */
  HANDLE h;               /* Handle for accessing the file */
  u8 locktype;            /* Type of lock currently held on this file */
  short sharedLockByte;   /* Randomly chosen byte used as a shared lock */
  u8 ctrlFlags;           /* Flags.  See WINFILE_* below */
  DWORD lastErrno;        /* The Windows errno from the last I/O error */
  DWORD sectorSize;       /* Sector size of the device file is on */
  winShm *pShm;           /* Instance of shared memory on this file */
  const char *zPath;      /* Full pathname of this file */
  int szChunk;            /* Chunk size configured by FCNTL_CHUNK_SIZE */
#if SQLITE_OS_WINCE
  LPWSTR zDeleteOnClose;  /* Name of file to delete when closing */
  HANDLE hMutex;          /* Mutex used to control access to shared lock */  
  HANDLE hShared;         /* Shared memory segment used for locking */
  winceLock local;        /* Locks obtained by this instance of winFile */
  winceLock *shared;      /* Global shared lock memory for the file  */
#endif
};

/*
** Allowed values for winFile.ctrlFlags
*/
#define WINFILE_PERSIST_WAL     0x04   /* Persistent WAL mode */
#define WINFILE_PSOW            0x10   /* SQLITE_IOCAP_POWERSAFE_OVERWRITE */

/*
 * If compiled with SQLITE_WIN32_MALLOC on Windows, we will use the
 * various Win32 API heap functions instead of our own.
 */
#ifdef SQLITE_WIN32_MALLOC
/*
 * The initial size of the Win32-specific heap.  This value may be zero.

static int getSectorSize(
    sqlite3_vfs *pVfs,
    const char *zRelative     /* UTF-8 file name */
);

/*
** The following variable is (normally) set once and never changes
** thereafter.  It records whether the operating system is Win9x
** or WinNT.
**
** 0:   Operating system unknown.
** 1:   Operating system is Win9x.
** 2:   Operating system is WinNT.
**
** In order to facilitate testing on a WinNT system, the test fixture
** can manually set this value to 1 to emulate Win98 behavior.
*/
#ifdef SQLITE_TEST
SQLITE_API int sqlite3_os_type = 0;
#else
static int sqlite3_os_type = 0;
#endif

/*
** Many system calls are accessed through pointer-to-functions so that
** they may be overridden at runtime to facilitate fault injection during
** testing and sandboxing.  The following array holds the names and pointers
** to all overrideable system calls.
*/
#if !SQLITE_OS_WINCE
#  define SQLITE_WIN32_HAS_ANSI
#endif

#if SQLITE_OS_WINCE || SQLITE_OS_WINNT
#  define SQLITE_WIN32_HAS_WIDE
#endif

#ifndef SYSCALL
#  define SYSCALL sqlite3_syscall_ptr
#endif

#if SQLITE_OS_WINCE
/*
** These macros are necessary because Windows CE does not natively support the
** Win32 APIs LockFile, UnlockFile, and LockFileEx.
 */

#  define LockFile(a,b,c,d,e)       winceLockFile(&a, b, c, d, e)
#  define UnlockFile(a,b,c,d,e)     winceUnlockFile(&a, b, c, d, e)
#  define LockFileEx(a,b,c,d,e,f)   winceLockFileEx(&a, b, c, d, e, f)

/*
** These are the special syscall hacks for Windows CE.  The locking related
** defines here refer to the macros defined just above.
 */

#  define osAreFileApisANSI()       1
#  define osLockFile                LockFile
#  define osUnlockFile              UnlockFile
#  define osLockFileEx              LockFileEx
#endif

static struct win_syscall {
  const char *zName;            /* Name of the sytem call */
  sqlite3_syscall_ptr pCurrent; /* Current value of the system call */
  sqlite3_syscall_ptr pDefault; /* Default value */
} aSyscall[] = {
#if !SQLITE_OS_WINCE
  { "AreFileApisANSI",         (SYSCALL)AreFileApisANSI,         0 },

#define osAreFileApisANSI ((BOOL(WINAPI*)(VOID))aSyscall[0].pCurrent)
#else
  { "AreFileApisANSI",         (SYSCALL)0,                       0 },
#endif

#if SQLITE_OS_WINCE && defined(SQLITE_WIN32_HAS_WIDE)
  { "CharLowerW",              (SYSCALL)CharLowerW,              0 },
#else
  { "CharLowerW",              (SYSCALL)0,                       0 },
#endif

#define osCharLowerW ((LPWSTR(WINAPI*)(LPWSTR))aSyscall[1].pCurrent)

#if SQLITE_OS_WINCE && defined(SQLITE_WIN32_HAS_WIDE)
  { "CharUpperW",              (SYSCALL)CharUpperW,              0 },
#else
  { "CharUpperW",              (SYSCALL)0,                       0 },
#endif

#define osCharUpperW ((LPWSTR(WINAPI*)(LPWSTR))aSyscall[2].pCurrent)

  { "CloseHandle",             (SYSCALL)CloseHandle,             0 },

#define osCloseHandle ((BOOL(WINAPI*)(HANDLE))aSyscall[3].pCurrent)

#if defined(SQLITE_WIN32_HAS_ANSI)
  { "CreateFileA",             (SYSCALL)CreateFileA,             0 },
#else
  { "CreateFileA",             (SYSCALL)0,                       0 },
#endif

#define osCreateFileA ((HANDLE(WINAPI*)(LPCSTR,DWORD,DWORD, \
        LPSECURITY_ATTRIBUTES,DWORD,DWORD,HANDLE))aSyscall[4].pCurrent)

#if defined(SQLITE_WIN32_HAS_WIDE)
  { "CreateFileW",             (SYSCALL)CreateFileW,             0 },
#else
  { "CreateFileW",             (SYSCALL)0,                       0 },
#endif

#define osCreateFileW ((HANDLE(WINAPI*)(LPCWSTR,DWORD,DWORD, \
        LPSECURITY_ATTRIBUTES,DWORD,DWORD,HANDLE))aSyscall[5].pCurrent)

  { "CreateFileMapping",       (SYSCALL)CreateFileMapping,       0 },

#define osCreateFileMapping ((HANDLE(WINAPI*)(HANDLE,LPSECURITY_ATTRIBUTES, \
        DWORD,DWORD,DWORD,LPCTSTR))aSyscall[6].pCurrent)

#if defined(SQLITE_WIN32_HAS_WIDE)
  { "CreateFileMappingW",      (SYSCALL)CreateFileMappingW,      0 },
#else
  { "CreateFileMappingW",      (SYSCALL)0,                       0 },
#endif

#define osCreateFileMappingW ((HANDLE(WINAPI*)(HANDLE,LPSECURITY_ATTRIBUTES, \
        DWORD,DWORD,DWORD,LPCWSTR))aSyscall[7].pCurrent)

#if defined(SQLITE_WIN32_HAS_WIDE)
  { "CreateMutexW",            (SYSCALL)CreateMutexW,            0 },
#else
  { "CreateMutexW",            (SYSCALL)0,                       0 },
#endif

#define osCreateMutexW ((HANDLE(WINAPI*)(LPSECURITY_ATTRIBUTES,BOOL, \
        LPCWSTR))aSyscall[8].pCurrent)

#if defined(SQLITE_WIN32_HAS_ANSI)
  { "DeleteFileA",             (SYSCALL)DeleteFileA,             0 },
#else
  { "DeleteFileA",             (SYSCALL)0,                       0 },
#endif

#define osDeleteFileA ((BOOL(WINAPI*)(LPCSTR))aSyscall[9].pCurrent)

#if defined(SQLITE_WIN32_HAS_WIDE)
  { "DeleteFileW",             (SYSCALL)DeleteFileW,             0 },
#else
  { "DeleteFileW",             (SYSCALL)0,                       0 },
#endif

#define osDeleteFileW ((BOOL(WINAPI*)(LPCWSTR))aSyscall[10].pCurrent)

#if SQLITE_OS_WINCE
  { "FileTimeToLocalFileTime", (SYSCALL)FileTimeToLocalFileTime, 0 },
#else
  { "FileTimeToLocalFileTime", (SYSCALL)0,                       0 },
#endif

#define osFileTimeToLocalFileTime ((BOOL(WINAPI*)(CONST FILETIME*, \
        LPFILETIME))aSyscall[11].pCurrent)

#if SQLITE_OS_WINCE
  { "FileTimeToSystemTime",    (SYSCALL)FileTimeToSystemTime,    0 },
#else
  { "FileTimeToSystemTime",    (SYSCALL)0,                       0 },
#endif

#define osFileTimeToSystemTime ((BOOL(WINAPI*)(CONST FILETIME*, \
        LPSYSTEMTIME))aSyscall[12].pCurrent)

  { "FlushFileBuffers",        (SYSCALL)FlushFileBuffers,        0 },

#define osFlushFileBuffers ((BOOL(WINAPI*)(HANDLE))aSyscall[13].pCurrent)

#if defined(SQLITE_WIN32_HAS_ANSI)
  { "FormatMessageA",          (SYSCALL)FormatMessageA,          0 },
#else
  { "FormatMessageA",          (SYSCALL)0,                       0 },
#endif

#define osFormatMessageA ((DWORD(WINAPI*)(DWORD,LPCVOID,DWORD,DWORD,LPSTR, \
        DWORD,va_list*))aSyscall[14].pCurrent)

#if defined(SQLITE_WIN32_HAS_WIDE)
  { "FormatMessageW",          (SYSCALL)FormatMessageW,          0 },
#else
  { "FormatMessageW",          (SYSCALL)0,                       0 },
#endif

#define osFormatMessageW ((DWORD(WINAPI*)(DWORD,LPCVOID,DWORD,DWORD,LPWSTR, \
        DWORD,va_list*))aSyscall[15].pCurrent)

  { "FreeLibrary",             (SYSCALL)FreeLibrary,             0 },

#define osFreeLibrary ((BOOL(WINAPI*)(HMODULE))aSyscall[16].pCurrent)

  { "GetCurrentProcessId",     (SYSCALL)GetCurrentProcessId,     0 },

#define osGetCurrentProcessId ((DWORD(WINAPI*)(VOID))aSyscall[17].pCurrent)

#if !SQLITE_OS_WINCE && defined(SQLITE_WIN32_HAS_ANSI)
  { "GetDiskFreeSpaceA",       (SYSCALL)GetDiskFreeSpaceA,       0 },
#else
  { "GetDiskFreeSpaceA",       (SYSCALL)0,                       0 },
#endif

#define osGetDiskFreeSpaceA ((BOOL(WINAPI*)(LPCSTR,LPDWORD,LPDWORD,LPDWORD, \
        LPDWORD))aSyscall[18].pCurrent)

#if !SQLITE_OS_WINCE && defined(SQLITE_WIN32_HAS_WIDE)
  { "GetDiskFreeSpaceW",       (SYSCALL)GetDiskFreeSpaceW,       0 },
#else
  { "GetDiskFreeSpaceW",       (SYSCALL)0,                       0 },
#endif

#define osGetDiskFreeSpaceW ((BOOL(WINAPI*)(LPCWSTR,LPDWORD,LPDWORD,LPDWORD, \
        LPDWORD))aSyscall[19].pCurrent)

#if defined(SQLITE_WIN32_HAS_ANSI)
  { "GetFileAttributesA",      (SYSCALL)GetFileAttributesA,      0 },
#else
  { "GetFileAttributesA",      (SYSCALL)0,                       0 },
#endif

#define osGetFileAttributesA ((DWORD(WINAPI*)(LPCSTR))aSyscall[20].pCurrent)

#if defined(SQLITE_WIN32_HAS_WIDE)
  { "GetFileAttributesW",      (SYSCALL)GetFileAttributesW,      0 },
#else
  { "GetFileAttributesW",      (SYSCALL)0,                       0 },
#endif

#define osGetFileAttributesW ((DWORD(WINAPI*)(LPCWSTR))aSyscall[21].pCurrent)

#if defined(SQLITE_WIN32_HAS_WIDE)
  { "GetFileAttributesExW",    (SYSCALL)GetFileAttributesExW,    0 },
#else
  { "GetFileAttributesExW",    (SYSCALL)0,                       0 },
#endif

#define osGetFileAttributesExW ((BOOL(WINAPI*)(LPCWSTR,GET_FILEEX_INFO_LEVELS, \
        LPVOID))aSyscall[22].pCurrent)

  { "GetFileSize",             (SYSCALL)GetFileSize,             0 },

#define osGetFileSize ((DWORD(WINAPI*)(HANDLE,LPDWORD))aSyscall[23].pCurrent)

#if !SQLITE_OS_WINCE && defined(SQLITE_WIN32_HAS_ANSI)
  { "GetFullPathNameA",        (SYSCALL)GetFullPathNameA,        0 },
#else
  { "GetFullPathNameA",        (SYSCALL)0,                       0 },
#endif

#define osGetFullPathNameA ((DWORD(WINAPI*)(LPCSTR,DWORD,LPSTR, \
        LPSTR*))aSyscall[24].pCurrent)

#if !SQLITE_OS_WINCE && defined(SQLITE_WIN32_HAS_WIDE)
  { "GetFullPathNameW",        (SYSCALL)GetFullPathNameW,        0 },
#else
  { "GetFullPathNameW",        (SYSCALL)0,                       0 },
#endif

#define osGetFullPathNameW ((DWORD(WINAPI*)(LPCWSTR,DWORD,LPWSTR, \
        LPWSTR*))aSyscall[25].pCurrent)

  { "GetLastError",            (SYSCALL)GetLastError,            0 },

#define osGetLastError ((DWORD(WINAPI*)(VOID))aSyscall[26].pCurrent)

#if SQLITE_OS_WINCE
  /* The GetProcAddressA() routine is only available on Windows CE. */
  { "GetProcAddressA",         (SYSCALL)GetProcAddressA,         0 },
#else
  /* All other Windows platforms expect GetProcAddress() to take
  ** an ANSI string regardless of the _UNICODE setting */
  { "GetProcAddressA",         (SYSCALL)GetProcAddress,          0 },
#endif

#define osGetProcAddressA ((FARPROC(WINAPI*)(HMODULE, \
        LPCSTR))aSyscall[27].pCurrent)

  { "GetSystemInfo",           (SYSCALL)GetSystemInfo,           0 },

#define osGetSystemInfo ((VOID(WINAPI*)(LPSYSTEM_INFO))aSyscall[28].pCurrent)

  { "GetSystemTime",           (SYSCALL)GetSystemTime,           0 },

#define osGetSystemTime ((VOID(WINAPI*)(LPSYSTEMTIME))aSyscall[29].pCurrent)

#if !SQLITE_OS_WINCE
  { "GetSystemTimeAsFileTime", (SYSCALL)GetSystemTimeAsFileTime, 0 },
#else
  { "GetSystemTimeAsFileTime", (SYSCALL)0,                       0 },
#endif

#define osGetSystemTimeAsFileTime ((VOID(WINAPI*)( \
        LPFILETIME))aSyscall[30].pCurrent)

#if defined(SQLITE_WIN32_HAS_ANSI)
  { "GetTempPathA",            (SYSCALL)GetTempPathA,            0 },
#else
  { "GetTempPathA",            (SYSCALL)0,                       0 },
#endif

#define osGetTempPathA ((DWORD(WINAPI*)(DWORD,LPSTR))aSyscall[31].pCurrent)

#if defined(SQLITE_WIN32_HAS_WIDE)
  { "GetTempPathW",            (SYSCALL)GetTempPathW,            0 },
#else
  { "GetTempPathW",            (SYSCALL)0,                       0 },
#endif

#define osGetTempPathW ((DWORD(WINAPI*)(DWORD,LPWSTR))aSyscall[32].pCurrent)

  { "GetTickCount",            (SYSCALL)GetTickCount,            0 },

#define osGetTickCount ((DWORD(WINAPI*)(VOID))aSyscall[33].pCurrent)

#if defined(SQLITE_WIN32_HAS_ANSI)
  { "GetVersionExA",           (SYSCALL)GetVersionExA,           0 },
#else
  { "GetVersionExA",           (SYSCALL)0,                       0 },
#endif

#define osGetVersionExA ((BOOL(WINAPI*)( \
        LPOSVERSIONINFOA))aSyscall[34].pCurrent)

  { "HeapAlloc",               (SYSCALL)HeapAlloc,               0 },

#define osHeapAlloc ((LPVOID(WINAPI*)(HANDLE,DWORD, \
        SIZE_T))aSyscall[35].pCurrent)

  { "HeapCreate",              (SYSCALL)HeapCreate,              0 },

#define osHeapCreate ((HANDLE(WINAPI*)(DWORD,SIZE_T, \
        SIZE_T))aSyscall[36].pCurrent)

  { "HeapDestroy",             (SYSCALL)HeapDestroy,             0 },

#define osHeapDestroy ((BOOL(WINAPI*)(HANDLE))aSyscall[37].pCurrent)

  { "HeapFree",                (SYSCALL)HeapFree,                0 },

#define osHeapFree ((BOOL(WINAPI*)(HANDLE,DWORD,LPVOID))aSyscall[38].pCurrent)

  { "HeapReAlloc",             (SYSCALL)HeapReAlloc,             0 },

#define osHeapReAlloc ((LPVOID(WINAPI*)(HANDLE,DWORD,LPVOID, \
        SIZE_T))aSyscall[39].pCurrent)

  { "HeapSize",                (SYSCALL)HeapSize,                0 },

#define osHeapSize ((SIZE_T(WINAPI*)(HANDLE,DWORD, \
        LPCVOID))aSyscall[40].pCurrent)

  { "HeapValidate",            (SYSCALL)HeapValidate,            0 },

#define osHeapValidate ((BOOL(WINAPI*)(HANDLE,DWORD, \
        LPCVOID))aSyscall[41].pCurrent)

#if defined(SQLITE_WIN32_HAS_ANSI)
  { "LoadLibraryA",            (SYSCALL)LoadLibraryA,            0 },
#else
  { "LoadLibraryA",            (SYSCALL)0,                       0 },
#endif

#define osLoadLibraryA ((HMODULE(WINAPI*)(LPCSTR))aSyscall[42].pCurrent)

#if defined(SQLITE_WIN32_HAS_WIDE)
  { "LoadLibraryW",            (SYSCALL)LoadLibraryW,            0 },
#else
  { "LoadLibraryW",            (SYSCALL)0,                       0 },
#endif

#define osLoadLibraryW ((HMODULE(WINAPI*)(LPCWSTR))aSyscall[43].pCurrent)

  { "LocalFree",               (SYSCALL)LocalFree,               0 },

#define osLocalFree ((HLOCAL(WINAPI*)(HLOCAL))aSyscall[44].pCurrent)

#if !SQLITE_OS_WINCE
  { "LockFile",                (SYSCALL)LockFile,                0 },

#define osLockFile ((BOOL(WINAPI*)(HANDLE,DWORD,DWORD,DWORD, \
        DWORD))aSyscall[45].pCurrent)
#else
  { "LockFile",                (SYSCALL)0,                       0 },
#endif

#if !SQLITE_OS_WINCE
  { "LockFileEx",              (SYSCALL)LockFileEx,              0 },

#define osLockFileEx ((BOOL(WINAPI*)(HANDLE,DWORD,DWORD,DWORD,DWORD, \
        LPOVERLAPPED))aSyscall[46].pCurrent)
#else
  { "LockFileEx",              (SYSCALL)0,                       0 },
#endif

  { "MapViewOfFile",           (SYSCALL)MapViewOfFile,           0 },

#define osMapViewOfFile ((LPVOID(WINAPI*)(HANDLE,DWORD,DWORD,DWORD, \
        SIZE_T))aSyscall[47].pCurrent)

  { "MultiByteToWideChar",     (SYSCALL)MultiByteToWideChar,     0 },

#define osMultiByteToWideChar ((int(WINAPI*)(UINT,DWORD,LPCSTR,int,LPWSTR, \
        int))aSyscall[48].pCurrent)

  { "QueryPerformanceCounter", (SYSCALL)QueryPerformanceCounter, 0 },

#define osQueryPerformanceCounter ((BOOL(WINAPI*)( \
        LARGE_INTEGER*))aSyscall[49].pCurrent)

  { "ReadFile",                (SYSCALL)ReadFile,                0 },

#define osReadFile ((BOOL(WINAPI*)(HANDLE,LPVOID,DWORD,LPDWORD, \
        LPOVERLAPPED))aSyscall[50].pCurrent)

  { "SetEndOfFile",            (SYSCALL)SetEndOfFile,            0 },

#define osSetEndOfFile ((BOOL(WINAPI*)(HANDLE))aSyscall[51].pCurrent)

  { "SetFilePointer",          (SYSCALL)SetFilePointer,          0 },

#define osSetFilePointer ((DWORD(WINAPI*)(HANDLE,LONG,PLONG, \
        DWORD))aSyscall[52].pCurrent)

  { "Sleep",                   (SYSCALL)Sleep,                   0 },

#define osSleep ((VOID(WINAPI*)(DWORD))aSyscall[53].pCurrent)

  { "SystemTimeToFileTime",    (SYSCALL)SystemTimeToFileTime,    0 },

#define osSystemTimeToFileTime ((BOOL(WINAPI*)(CONST SYSTEMTIME*, \
        LPFILETIME))aSyscall[54].pCurrent)

#if !SQLITE_OS_WINCE
  { "UnlockFile",              (SYSCALL)UnlockFile,              0 },

#define osUnlockFile ((BOOL(WINAPI*)(HANDLE,DWORD,DWORD,DWORD, \
        DWORD))aSyscall[55].pCurrent)
#else
  { "UnlockFile",              (SYSCALL)0,                       0 },
#endif

#if !SQLITE_OS_WINCE
  { "UnlockFileEx",            (SYSCALL)UnlockFileEx,            0 },

#define osUnlockFileEx ((BOOL(WINAPI*)(HANDLE,DWORD,DWORD,DWORD, \
        LPOVERLAPPED))aSyscall[56].pCurrent)
#else
  { "UnlockFileEx",            (SYSCALL)0,                       0 },
#endif

  { "UnmapViewOfFile",         (SYSCALL)UnmapViewOfFile,         0 },

#define osUnmapViewOfFile ((BOOL(WINAPI*)(LPCVOID))aSyscall[57].pCurrent)

  { "WideCharToMultiByte",     (SYSCALL)WideCharToMultiByte,     0 },

#define osWideCharToMultiByte ((int(WINAPI*)(UINT,DWORD,LPCWSTR,int,LPSTR,int, \
        LPCSTR,LPBOOL))aSyscall[58].pCurrent)

  { "WriteFile",               (SYSCALL)WriteFile,               0 },

#define osWriteFile ((BOOL(WINAPI*)(HANDLE,LPCVOID,DWORD,LPDWORD, \
        LPOVERLAPPED))aSyscall[59].pCurrent)

}; /* End of the overrideable system calls */

/*
** This is the xSetSystemCall() method of sqlite3_vfs for all of the
** "win32" VFSes.  Return SQLITE_OK opon successfully updating the
** system call pointer, or SQLITE_NOTFOUND if there is no configurable
** system call named zName.
*/
static int winSetSystemCall(
  sqlite3_vfs *pNotUsed,        /* The VFS pointer.  Not used */
  const char *zName,            /* Name of system call to override */
  sqlite3_syscall_ptr pNewFunc  /* Pointer to new system call value */
){
  unsigned int i;
  int rc = SQLITE_NOTFOUND;

  UNUSED_PARAMETER(pNotUsed);
  if( zName==0 ){
    /* If no zName is given, restore all system calls to their default
    ** settings and return NULL
    */
    rc = SQLITE_OK;
    for(i=0; i<sizeof(aSyscall)/sizeof(aSyscall[0]); i++){
      if( aSyscall[i].pDefault ){
        aSyscall[i].pCurrent = aSyscall[i].pDefault;
      }
    }
  }else{
    /* If zName is specified, operate on only the one system call
    ** specified.
    */
    for(i=0; i<sizeof(aSyscall)/sizeof(aSyscall[0]); i++){
      if( strcmp(zName, aSyscall[i].zName)==0 ){
        if( aSyscall[i].pDefault==0 ){
          aSyscall[i].pDefault = aSyscall[i].pCurrent;
        }
        rc = SQLITE_OK;
        if( pNewFunc==0 ) pNewFunc = aSyscall[i].pDefault;
        aSyscall[i].pCurrent = pNewFunc;
        break;
      }
    }
  }
  return rc;
}

/*
** Return the value of a system call.  Return NULL if zName is not a
** recognized system call name.  NULL is also returned if the system call
** is currently undefined.
*/
static sqlite3_syscall_ptr winGetSystemCall(
  sqlite3_vfs *pNotUsed,
  const char *zName
){
  unsigned int i;

  UNUSED_PARAMETER(pNotUsed);
  for(i=0; i<sizeof(aSyscall)/sizeof(aSyscall[0]); i++){
    if( strcmp(zName, aSyscall[i].zName)==0 ) return aSyscall[i].pCurrent;
  }
  return 0;
}

/*
** Return the name of the first system call after zName.  If zName==NULL
** then return the name of the first system call.  Return NULL if zName
** is the last system call or if zName is not the name of a valid
** system call.
*/
static const char *winNextSystemCall(sqlite3_vfs *p, const char *zName){
  int i = -1;

  UNUSED_PARAMETER(p);
  if( zName ){
    for(i=0; i<ArraySize(aSyscall)-1; i++){
      if( strcmp(zName, aSyscall[i].zName)==0 ) break;
    }
  }
  for(i++; i<ArraySize(aSyscall); i++){
    if( aSyscall[i].pCurrent!=0 ) return aSyscall[i].zName;
  }
  return 0;
}

/*
** Return true (non-zero) if we are running under WinNT, Win2K, WinXP,
** or WinCE.  Return false (zero) for Win95, Win98, or WinME.
**
** Here is an interesting observation:  Win95, Win98, and WinME lack
** the LockFileEx() API.  But we can still statically link against that
** API as long as we don't call it when running Win95/98/ME.  A call to
** this routine is used to determine if the host is Win95/98/ME or
** WinNT/2K/XP so that we will know whether or not we can safely call
** the LockFileEx() API.
*/
#if SQLITE_OS_WINCE
# define isNT()  (1)
#else
  static int isNT(void){
    if( sqlite3_os_type==0 ){
      OSVERSIONINFOA sInfo;
      sInfo.dwOSVersionInfoSize = sizeof(sInfo);
      osGetVersionExA(&sInfo);
      sqlite3_os_type = sInfo.dwPlatformId==VER_PLATFORM_WIN32_NT ? 2 : 1;
    }
    return sqlite3_os_type==2;
  }
#endif /* SQLITE_OS_WINCE */

#ifdef SQLITE_WIN32_MALLOC
/*
** Allocate nBytes of memory.
*/
static void *winMemMalloc(int nBytes){
  HANDLE hHeap;
  void *p;

  winMemAssertMagic();
  hHeap = winMemGetHeap();
  assert( hHeap!=0 );
  assert( hHeap!=INVALID_HANDLE_VALUE );
#ifdef SQLITE_WIN32_MALLOC_VALIDATE
  assert ( osHeapValidate(hHeap, SQLITE_WIN32_HEAP_FLAGS, NULL) );
#endif
  assert( nBytes>=0 );
  p = osHeapAlloc(hHeap, SQLITE_WIN32_HEAP_FLAGS, (SIZE_T)nBytes);
  if( !p ){
    sqlite3_log(SQLITE_NOMEM, "failed to HeapAlloc %u bytes (%d), heap=%p",
                nBytes, osGetLastError(), (void*)hHeap);
  }
  return p;
}

/*
** Free memory.
*/
static void winMemFree(void *pPrior){
  HANDLE hHeap;

  winMemAssertMagic();
  hHeap = winMemGetHeap();
  assert( hHeap!=0 );
  assert( hHeap!=INVALID_HANDLE_VALUE );
#ifdef SQLITE_WIN32_MALLOC_VALIDATE
  assert ( osHeapValidate(hHeap, SQLITE_WIN32_HEAP_FLAGS, pPrior) );
#endif
  if( !pPrior ) return; /* Passing NULL to HeapFree is undefined. */
  if( !osHeapFree(hHeap, SQLITE_WIN32_HEAP_FLAGS, pPrior) ){
    sqlite3_log(SQLITE_NOMEM, "failed to HeapFree block %p (%d), heap=%p",
                pPrior, osGetLastError(), (void*)hHeap);
  }
}

/*
** Change the size of an existing memory allocation
*/
static void *winMemRealloc(void *pPrior, int nBytes){
  HANDLE hHeap;
  void *p;

  winMemAssertMagic();
  hHeap = winMemGetHeap();
  assert( hHeap!=0 );
  assert( hHeap!=INVALID_HANDLE_VALUE );
#ifdef SQLITE_WIN32_MALLOC_VALIDATE
  assert ( osHeapValidate(hHeap, SQLITE_WIN32_HEAP_FLAGS, pPrior) );
#endif
  assert( nBytes>=0 );
  if( !pPrior ){
    p = osHeapAlloc(hHeap, SQLITE_WIN32_HEAP_FLAGS, (SIZE_T)nBytes);
  }else{
    p = osHeapReAlloc(hHeap, SQLITE_WIN32_HEAP_FLAGS, pPrior, (SIZE_T)nBytes);
  }
  if( !p ){
    sqlite3_log(SQLITE_NOMEM, "failed to %s %u bytes (%d), heap=%p",
                pPrior ? "HeapReAlloc" : "HeapAlloc", nBytes, osGetLastError(),
                (void*)hHeap);
  }
  return p;
}

/*
** Return the size of an outstanding allocation, in bytes.
*/
static int winMemSize(void *p){
  HANDLE hHeap;
  SIZE_T n;

  winMemAssertMagic();
  hHeap = winMemGetHeap();
  assert( hHeap!=0 );
  assert( hHeap!=INVALID_HANDLE_VALUE );
#ifdef SQLITE_WIN32_MALLOC_VALIDATE
  assert ( osHeapValidate(hHeap, SQLITE_WIN32_HEAP_FLAGS, NULL) );
#endif
  if( !p ) return 0;
  n = osHeapSize(hHeap, SQLITE_WIN32_HEAP_FLAGS, p);
  if( n==(SIZE_T)-1 ){
    sqlite3_log(SQLITE_NOMEM, "failed to HeapSize block %p (%d), heap=%p",
                p, osGetLastError(), (void*)hHeap);
    return 0;
  }
  return (int)n;
}

/*
** Round up a request size to the next valid allocation size.

*/
static int winMemInit(void *pAppData){
  winMemData *pWinMemData = (winMemData *)pAppData;

  if( !pWinMemData ) return SQLITE_ERROR;
  assert( pWinMemData->magic==WINMEM_MAGIC );
  if( !pWinMemData->hHeap ){
    pWinMemData->hHeap = osHeapCreate(SQLITE_WIN32_HEAP_FLAGS,
                                      SQLITE_WIN32_HEAP_INIT_SIZE,
                                      SQLITE_WIN32_HEAP_MAX_SIZE);
    if( !pWinMemData->hHeap ){
      sqlite3_log(SQLITE_NOMEM,
          "failed to HeapCreate (%d), flags=%u, initSize=%u, maxSize=%u",
          osGetLastError(), SQLITE_WIN32_HEAP_FLAGS,
          SQLITE_WIN32_HEAP_INIT_SIZE, SQLITE_WIN32_HEAP_MAX_SIZE);
      return SQLITE_NOMEM;
    }
    pWinMemData->bOwned = TRUE;
  }
  assert( pWinMemData->hHeap!=0 );
  assert( pWinMemData->hHeap!=INVALID_HANDLE_VALUE );
#ifdef SQLITE_WIN32_MALLOC_VALIDATE
  assert( osHeapValidate(pWinMemData->hHeap, SQLITE_WIN32_HEAP_FLAGS, NULL) );
#endif
  return SQLITE_OK;
}

/*
** Deinitialize this module.
*/
static void winMemShutdown(void *pAppData){
  winMemData *pWinMemData = (winMemData *)pAppData;

  if( !pWinMemData ) return;
  if( pWinMemData->hHeap ){
    assert( pWinMemData->hHeap!=INVALID_HANDLE_VALUE );
#ifdef SQLITE_WIN32_MALLOC_VALIDATE
    assert( osHeapValidate(pWinMemData->hHeap, SQLITE_WIN32_HEAP_FLAGS, NULL) );
#endif
    if( pWinMemData->bOwned ){
      if( !osHeapDestroy(pWinMemData->hHeap) ){
        sqlite3_log(SQLITE_NOMEM, "failed to HeapDestroy (%d), heap=%p",
                    osGetLastError(), (void*)pWinMemData->hHeap);
      }
      pWinMemData->bOwned = FALSE;
    }
    pWinMemData->hHeap = NULL;
  }
}

SQLITE_PRIVATE void sqlite3MemSetDefault(void){
  sqlite3_config(SQLITE_CONFIG_MALLOC, sqlite3MemGetWin32());
}
#endif /* SQLITE_WIN32_MALLOC */

/*
** Convert a UTF-8 string to Microsoft Unicode (UTF-16?). 
**
** Space to hold the returned string is obtained from malloc.
*/
static LPWSTR utf8ToUnicode(const char *zFilename){
  int nChar;
  LPWSTR zWideFilename;

  nChar = osMultiByteToWideChar(CP_UTF8, 0, zFilename, -1, NULL, 0);
  if( nChar==0 ){
    return 0;
  }
  zWideFilename = sqlite3_malloc( nChar*sizeof(zWideFilename[0]) );
  if( zWideFilename==0 ){
    return 0;
  }
  nChar = osMultiByteToWideChar(CP_UTF8, 0, zFilename, -1, zWideFilename,
                                nChar);
  if( nChar==0 ){
    sqlite3_free(zWideFilename);
    zWideFilename = 0;
  }
  return zWideFilename;
}

/*
** Convert Microsoft Unicode to UTF-8.  Space to hold the returned string is
** obtained from sqlite3_malloc().
*/
static char *unicodeToUtf8(LPCWSTR zWideFilename){
  int nByte;
  char *zFilename;

  nByte = osWideCharToMultiByte(CP_UTF8, 0, zWideFilename, -1, 0, 0, 0, 0);
  if( nByte == 0 ){
    return 0;
  }
  zFilename = sqlite3_malloc( nByte );
  if( zFilename==0 ){
    return 0;
  }
  nByte = osWideCharToMultiByte(CP_UTF8, 0, zWideFilename, -1, zFilename, nByte,
                                0, 0);
  if( nByte == 0 ){
    sqlite3_free(zFilename);
    zFilename = 0;
  }
  return zFilename;
}

/*
** Convert an ANSI string to Microsoft Unicode, based on the
** current codepage settings for file apis.
** 
** Space to hold the returned string is obtained
** from sqlite3_malloc.
*/
static LPWSTR mbcsToUnicode(const char *zFilename){
  int nByte;
  LPWSTR zMbcsFilename;
  int codepage = osAreFileApisANSI() ? CP_ACP : CP_OEMCP;

  nByte = osMultiByteToWideChar(codepage, 0, zFilename, -1, NULL,
                                0)*sizeof(WCHAR);
  if( nByte==0 ){
    return 0;
  }
  zMbcsFilename = sqlite3_malloc( nByte*sizeof(zMbcsFilename[0]) );
  if( zMbcsFilename==0 ){
    return 0;
  }
  nByte = osMultiByteToWideChar(codepage, 0, zFilename, -1, zMbcsFilename,
                                nByte);
  if( nByte==0 ){
    sqlite3_free(zMbcsFilename);
    zMbcsFilename = 0;
  }
  return zMbcsFilename;
}

/*
** Convert Microsoft Unicode to multi-byte character string, based on the
** user's ANSI codepage.
**
** Space to hold the returned string is obtained from
** sqlite3_malloc().
*/
static char *unicodeToMbcs(LPCWSTR zWideFilename){
  int nByte;
  char *zFilename;
  int codepage = osAreFileApisANSI() ? CP_ACP : CP_OEMCP;

  nByte = osWideCharToMultiByte(codepage, 0, zWideFilename, -1, 0, 0, 0, 0);
  if( nByte == 0 ){
    return 0;
  }
  zFilename = sqlite3_malloc( nByte );
  if( zFilename==0 ){
    return 0;
  }
  nByte = osWideCharToMultiByte(codepage, 0, zWideFilename, -1, zFilename,
                                nByte, 0, 0);
  if( nByte == 0 ){
    sqlite3_free(zFilename);
    zFilename = 0;
  }
  return zFilename;
}

/*
** Convert multibyte character string to UTF-8.  Space to hold the
** returned string is obtained from sqlite3_malloc().
*/
SQLITE_API char *sqlite3_win32_mbcs_to_utf8(const char *zFilename){
  char *zFilenameUtf8;
  LPWSTR zTmpWide;

  zTmpWide = mbcsToUnicode(zFilename);
  if( zTmpWide==0 ){
    return 0;
  }
  zFilenameUtf8 = unicodeToUtf8(zTmpWide);
  sqlite3_free(zTmpWide);
  return zFilenameUtf8;
}

/*
** Convert UTF-8 to multibyte character string.  Space to hold the 
** returned string is obtained from sqlite3_malloc().
*/
SQLITE_API char *sqlite3_win32_utf8_to_mbcs(const char *zFilename){
  char *zFilenameMbcs;
  LPWSTR zTmpWide;

  zTmpWide = utf8ToUnicode(zFilename);
  if( zTmpWide==0 ){
    return 0;
  }
  zFilenameMbcs = unicodeToMbcs(zTmpWide);
  sqlite3_free(zTmpWide);
  return zFilenameMbcs;
}


/*
** The return value of getLastErrorMsg
** is zero if the error message fits in the buffer, or non-zero
** otherwise (if the message was truncated).
*/
static int getLastErrorMsg(DWORD lastErrno, int nBuf, char *zBuf){
  /* FormatMessage returns 0 on failure.  Otherwise it
  ** returns the number of TCHARs written to the output
  ** buffer, excluding the terminating null char.
  */

  DWORD dwLen = 0;
  char *zOut = 0;

  if( isNT() ){
    LPWSTR zTempWide = NULL;
    dwLen = osFormatMessageW(FORMAT_MESSAGE_ALLOCATE_BUFFER |
                             FORMAT_MESSAGE_FROM_SYSTEM |
                             FORMAT_MESSAGE_IGNORE_INSERTS,
                             NULL,
                             lastErrno,
                             0,
                             (LPWSTR) &zTempWide,
                             0,
                             0);
    if( dwLen > 0 ){
      /* allocate a buffer and convert to UTF8 */
      sqlite3BeginBenignMalloc();
      zOut = unicodeToUtf8(zTempWide);
      sqlite3EndBenignMalloc();
      /* free the system buffer allocated by FormatMessage */
      osLocalFree(zTempWide);
    }
/* isNT() is 1 if SQLITE_OS_WINCE==1, so this else is never executed. 
** Since the ANSI version of these Windows API do not exist for WINCE,
** it's important to not reference them for WINCE builds.
*/
#if SQLITE_OS_WINCE==0
  }else{
    char *zTemp = NULL;
    dwLen = osFormatMessageA(FORMAT_MESSAGE_ALLOCATE_BUFFER |
                             FORMAT_MESSAGE_FROM_SYSTEM |
                             FORMAT_MESSAGE_IGNORE_INSERTS,
                             NULL,
                             lastErrno,
                             0,
                             (LPSTR) &zTemp,
                             0,
                             0);
    if( dwLen > 0 ){
      /* allocate a buffer and convert to UTF8 */
      sqlite3BeginBenignMalloc();
      zOut = sqlite3_win32_mbcs_to_utf8(zTemp);
      sqlite3EndBenignMalloc();
      /* free the system buffer allocated by FormatMessage */
      osLocalFree(zTemp);
    }
#endif
  }
  if( 0 == dwLen ){
    sqlite3_snprintf(nBuf, zBuf, "OsError 0x%x (%u)", lastErrno, lastErrno);
  }else{
    /* copy a maximum of nBuf chars to output buffer */
    sqlite3_snprintf(nBuf, zBuf, "%s", zOut);
    /* free the UTF8 buffer */
    sqlite3_free(zOut);
  }
  return 0;
}

/*
**
** This function - winLogErrorAtLine() - is only ever called via the macro
** winLogError().
**
** This routine is invoked after an error occurs in an OS function.
** It logs a message using sqlite3_log() containing the current value of
** error code and, if possible, the human-readable equivalent from 
** FormatMessage.
**
** The first argument passed to the macro should be the error code that
** will be returned to SQLite (e.g. SQLITE_IOERR_DELETE, SQLITE_CANTOPEN). 
** The two subsequent arguments should be the name of the OS function that
** failed and the the associated file-system path, if any.
*/
#define winLogError(a,b,c,d)   winLogErrorAtLine(a,b,c,d,__LINE__)
static int winLogErrorAtLine(
  int errcode,                    /* SQLite error code */
  DWORD lastErrno,                /* Win32 last error */
  const char *zFunc,              /* Name of OS function that failed */
  const char *zPath,              /* File path associated with error */
  int iLine                       /* Source line number where error occurred */
){
  char zMsg[500];                 /* Human readable error text */
  int i;                          /* Loop counter */


  zMsg[0] = 0;
  getLastErrorMsg(lastErrno, sizeof(zMsg), zMsg);
  assert( errcode!=SQLITE_OK );
  if( zPath==0 ) zPath = "";
  for(i=0; zMsg[i] && zMsg[i]!='\r' && zMsg[i]!='\n'; i++){}
  zMsg[i] = 0;
  sqlite3_log(errcode,
      "os_win.c:%d: (%d) %s(%s) - %s",
      iLine, lastErrno, zFunc, zPath, zMsg
  );

  return errcode;
}

/*
** The number of times that a ReadFile(), WriteFile(), and DeleteFile()

static int win32IoerrRetryDelay = SQLITE_WIN32_IOERR_RETRY_DELAY;

/*
** If a ReadFile() or WriteFile() error occurs, invoke this routine
** to see if it should be retried.  Return TRUE to retry.  Return FALSE
** to give up with an error.
*/
static int retryIoerr(int *pnRetry, DWORD *pError){
  DWORD e = osGetLastError();
  if( *pnRetry>=win32IoerrRetry ){
    if( pError ){
      *pError = e;
    }
    return 0;
  }

  if( e==ERROR_ACCESS_DENIED ||
      e==ERROR_LOCK_VIOLATION ||
      e==ERROR_SHARING_VIOLATION ){
    osSleep(win32IoerrRetryDelay*(1+*pnRetry));
    ++*pnRetry;
    return 1;
  }
  if( pError ){
    *pError = e;
  }
  return 0;
}

/*
** Log a I/O error retry episode.
*/
static void logIoerr(int nRetry){
  if( nRetry ){
    sqlite3_log(SQLITE_IOERR, 
      "delayed %dms for lock/sharing conflict",
      win32IoerrRetryDelay*nRetry*(nRetry+1)/2
    );
  }
}

#if SQLITE_OS_WINCE
/*************************************************************************
** This section contains code for WinCE only.
*/
/*
** Windows CE does not have a localtime() function.  So create a
** substitute.
*/
/* #include <time.h> */
struct tm *__cdecl localtime(const time_t *t)
{
  static struct tm y;
  FILETIME uTm, lTm;
  SYSTEMTIME pTm;
  sqlite3_int64 t64;
  t64 = *t;
  t64 = (t64 + 11644473600)*10000000;
  uTm.dwLowDateTime = (DWORD)(t64 & 0xFFFFFFFF);
  uTm.dwHighDateTime= (DWORD)(t64 >> 32);
  osFileTimeToLocalFileTime(&uTm,&lTm);
  osFileTimeToSystemTime(&lTm,&pTm);
  y.tm_year = pTm.wYear - 1900;
  y.tm_mon = pTm.wMonth - 1;
  y.tm_wday = pTm.wDayOfWeek;
  y.tm_mday = pTm.wDay;
  y.tm_hour = pTm.wHour;
  y.tm_min = pTm.wMinute;
  y.tm_sec = pTm.wSecond;
  return &y;
}








#define HANDLE_TO_WINFILE(a) (winFile*)&((char*)a)[-(int)offsetof(winFile,h)]

/*
** Acquire a lock on the handle h
*/
static void winceMutexAcquire(HANDLE h){
   DWORD dwErr;

#define winceMutexRelease(h) ReleaseMutex(h)

/*
** Create the mutex and shared memory used for locking in the file
** descriptor pFile
*/
static BOOL winceCreateLock(const char *zFilename, winFile *pFile){
  LPWSTR zTok;
  LPWSTR zName;
  BOOL bInit = TRUE;

  zName = utf8ToUnicode(zFilename);
  if( zName==0 ){
    /* out of memory */
    return FALSE;
  }

  /* Initialize the local lockdata */
  memset(&pFile->local, 0, sizeof(pFile->local));

  /* Replace the backslashes from the filename and lowercase it
  ** to derive a mutex name. */
  zTok = osCharLowerW(zName);
  for (;*zTok;zTok++){
    if (*zTok == '\\') *zTok = '_';
  }

  /* Create/open the named mutex */
  pFile->hMutex = osCreateMutexW(NULL, FALSE, zName);
  if (!pFile->hMutex){
    pFile->lastErrno = osGetLastError();
    winLogError(SQLITE_ERROR, pFile->lastErrno, "winceCreateLock1", zFilename);
    sqlite3_free(zName);
    return FALSE;
  }

  /* Acquire the mutex before continuing */
  winceMutexAcquire(pFile->hMutex);
  
  /* Since the names of named mutexes, semaphores, file mappings etc are 
  ** case-sensitive, take advantage of that by uppercasing the mutex name
  ** and using that as the shared filemapping name.
  */
  osCharUpperW(zName);
  pFile->hShared = osCreateFileMappingW(INVALID_HANDLE_VALUE, NULL,
                                        PAGE_READWRITE, 0, sizeof(winceLock),
                                        zName);  

  /* Set a flag that indicates we're the first to create the memory so it 
  ** must be zero-initialized */
  if (osGetLastError() == ERROR_ALREADY_EXISTS){
    bInit = FALSE;
  }

  sqlite3_free(zName);

  /* If we succeeded in making the shared memory handle, map it. */
  if (pFile->hShared){
    pFile->shared = (winceLock*)osMapViewOfFile(pFile->hShared, 
             FILE_MAP_READ|FILE_MAP_WRITE, 0, 0, sizeof(winceLock));
    /* If mapping failed, close the shared memory handle and erase it */
    if (!pFile->shared){
      pFile->lastErrno = osGetLastError();
      winLogError(SQLITE_ERROR, pFile->lastErrno,
               "winceCreateLock2", zFilename);
      osCloseHandle(pFile->hShared);
      pFile->hShared = NULL;
    }
  }

  /* If shared memory could not be created, then close the mutex and fail */
  if (pFile->hShared == NULL){
    winceMutexRelease(pFile->hMutex);
    osCloseHandle(pFile->hMutex);
    pFile->hMutex = NULL;
    return FALSE;
  }
  
  /* Initialize the shared memory if we're supposed to */
  if (bInit) {
    memset(pFile->shared, 0, sizeof(winceLock));
  }

  winceMutexRelease(pFile->hMutex);
  return TRUE;
}

/*

      pFile->shared->bPending = FALSE;
    }
    if (pFile->local.bExclusive){
      pFile->shared->bExclusive = FALSE;
    }

    /* De-reference and close our copy of the shared memory handle */
    osUnmapViewOfFile(pFile->shared);
    osCloseHandle(pFile->hShared);

    /* Done with the mutex */
    winceMutexRelease(pFile->hMutex);    
    osCloseHandle(pFile->hMutex);
    pFile->hMutex = NULL;
  }
}

/* 
** An implementation of the LockFile() API of Windows for CE
*/
static BOOL winceLockFile(
  HANDLE *phFile,
  DWORD dwFileOffsetLow,
  DWORD dwFileOffsetHigh,
  DWORD nNumberOfBytesToLockLow,
  DWORD nNumberOfBytesToLockHigh

  }

  winceMutexRelease(pFile->hMutex);
  return bReturn;
}

/*
** An implementation of the UnlockFile API of Windows for CE
*/
static BOOL winceUnlockFile(
  HANDLE *phFile,
  DWORD dwFileOffsetLow,
  DWORD dwFileOffsetHigh,
  DWORD nNumberOfBytesToUnlockLow,
  DWORD nNumberOfBytesToUnlockHigh

  }

  winceMutexRelease(pFile->hMutex);
  return bReturn;
}

/*
** An implementation of the LockFileEx() API of Windows for CE
*/
static BOOL winceLockFileEx(
  HANDLE *phFile,
  DWORD dwFlags,
  DWORD dwReserved,
  DWORD nNumberOfBytesToLockLow,
  DWORD nNumberOfBytesToLockHigh,

/*****************************************************************************
** The next group of routines implement the I/O methods specified
** by the sqlite3_io_methods object.
******************************************************************************/

/*
** Some Microsoft compilers lack this definition.
*/
#ifndef INVALID_SET_FILE_POINTER
# define INVALID_SET_FILE_POINTER ((DWORD)-1)
#endif

/*
** Move the current position of the file handle passed as the first 
** argument to offset iOffset within the file. If successful, return 0. 
** Otherwise, set pFile->lastErrno and return non-zero.
*/
static int seekWinFile(winFile *pFile, sqlite3_int64 iOffset){
  LONG upperBits;                 /* Most sig. 32 bits of new offset */
  LONG lowerBits;                 /* Least sig. 32 bits of new offset */
  DWORD dwRet;                    /* Value returned by SetFilePointer() */
  DWORD lastErrno;                /* Value returned by GetLastError() */

  upperBits = (LONG)((iOffset>>32) & 0x7fffffff);
  lowerBits = (LONG)(iOffset & 0xffffffff);

  /* API oddity: If successful, SetFilePointer() returns a dword 
  ** containing the lower 32-bits of the new file-offset. Or, if it fails,
  ** it returns INVALID_SET_FILE_POINTER. However according to MSDN, 
  ** INVALID_SET_FILE_POINTER may also be a valid new offset. So to determine 
  ** whether an error has actually occured, it is also necessary to call 
  ** GetLastError().
  */
  dwRet = osSetFilePointer(pFile->h, lowerBits, &upperBits, FILE_BEGIN);

  if( (dwRet==INVALID_SET_FILE_POINTER
      && ((lastErrno = osGetLastError())!=NO_ERROR)) ){
    pFile->lastErrno = lastErrno;
    winLogError(SQLITE_IOERR_SEEK, pFile->lastErrno,
             "seekWinFile", pFile->zPath);
    return 1;
  }

  return 0;
}

/*
** Close a file.
**
** It is reported that an attempt to close a handle might sometimes
** fail.  This is a very unreasonable result, but Windows is notorious
** for being unreasonable so I do not doubt that it might happen.  If
** the close fails, we pause for 100 milliseconds and try again.  As
** many as MX_CLOSE_ATTEMPT attempts to close the handle are made before
** giving up and returning an error.
*/
#define MX_CLOSE_ATTEMPT 3
static int winClose(sqlite3_file *id){
  int rc, cnt = 0;
  winFile *pFile = (winFile*)id;

  assert( id!=0 );
  assert( pFile->pShm==0 );
  OSTRACE(("CLOSE %d\n", pFile->h));
  do{
    rc = osCloseHandle(pFile->h);
    /* SimulateIOError( rc=0; cnt=MX_CLOSE_ATTEMPT; ); */
  }while( rc==0 && ++cnt < MX_CLOSE_ATTEMPT && (osSleep(100), 1) );
#if SQLITE_OS_WINCE
#define WINCE_DELETION_ATTEMPTS 3
  winceDestroyLock(pFile);
  if( pFile->zDeleteOnClose ){
    int cnt = 0;
    while(
           osDeleteFileW(pFile->zDeleteOnClose)==0
        && osGetFileAttributesW(pFile->zDeleteOnClose)!=0xffffffff 
        && cnt++ < WINCE_DELETION_ATTEMPTS
    ){
       osSleep(100);  /* Wait a little before trying again */
    }
    sqlite3_free(pFile->zDeleteOnClose);
  }
#endif
  OSTRACE(("CLOSE %d %s\n", pFile->h, rc ? "ok" : "failed"));
  OpenCounter(-1);
  return rc ? SQLITE_OK
            : winLogError(SQLITE_IOERR_CLOSE, osGetLastError(),
                          "winClose", pFile->zPath);
}

/*
** Read data from a file into a buffer.  Return SQLITE_OK if all
** bytes were read successfully and SQLITE_IOERR if anything goes
** wrong.
*/

  assert( id!=0 );
  SimulateIOError(return SQLITE_IOERR_READ);
  OSTRACE(("READ %d lock=%d\n", pFile->h, pFile->locktype));

  if( seekWinFile(pFile, offset) ){
    return SQLITE_FULL;
  }
  while( !osReadFile(pFile->h, pBuf, amt, &nRead, 0) ){
    DWORD lastErrno;
    if( retryIoerr(&nRetry, &lastErrno) ) continue;
    pFile->lastErrno = lastErrno;
    return winLogError(SQLITE_IOERR_READ, pFile->lastErrno,
             "winRead", pFile->zPath);
  }
  logIoerr(nRetry);
  if( nRead<(DWORD)amt ){
    /* Unread parts of the buffer must be zero-filled */
    memset(&((char*)pBuf)[nRead], 0, amt-nRead);
    return SQLITE_IOERR_SHORT_READ;
  }

  OSTRACE(("WRITE %d lock=%d\n", pFile->h, pFile->locktype));

  rc = seekWinFile(pFile, offset);
  if( rc==0 ){
    u8 *aRem = (u8 *)pBuf;        /* Data yet to be written */
    int nRem = amt;               /* Number of bytes yet to be written */
    DWORD nWrite;                 /* Bytes written by each WriteFile() call */
    DWORD lastErrno = NO_ERROR;   /* Value returned by GetLastError() */

    while( nRem>0 ){
      if( !osWriteFile(pFile->h, aRem, nRem, &nWrite, 0) ){
        if( retryIoerr(&nRetry, &lastErrno) ) continue;
        break;
      }
      if( nWrite<=0 ) break;
      aRem += nWrite;
      nRem -= nWrite;
    }
    if( nRem>0 ){
      pFile->lastErrno = lastErrno;
      rc = 1;
    }
  }

  if( rc ){
    if(   ( pFile->lastErrno==ERROR_HANDLE_DISK_FULL )
       || ( pFile->lastErrno==ERROR_DISK_FULL )){
      return SQLITE_FULL;
    }
    return winLogError(SQLITE_IOERR_WRITE, pFile->lastErrno,
             "winWrite", pFile->zPath);
  }else{
    logIoerr(nRetry);
  }
  return SQLITE_OK;
}

/*

  */
  if( pFile->szChunk>0 ){
    nByte = ((nByte + pFile->szChunk - 1)/pFile->szChunk) * pFile->szChunk;
  }

  /* SetEndOfFile() returns non-zero when successful, or zero when it fails. */
  if( seekWinFile(pFile, nByte) ){
    rc = winLogError(SQLITE_IOERR_TRUNCATE, pFile->lastErrno,
             "winTruncate1", pFile->zPath);
  }else if( 0==osSetEndOfFile(pFile->h) ){
    pFile->lastErrno = osGetLastError();
    rc = winLogError(SQLITE_IOERR_TRUNCATE, pFile->lastErrno,
             "winTruncate2", pFile->zPath);
  }

  OSTRACE(("TRUNCATE %d %lld %s\n", pFile->h, nByte, rc ? "failed" : "ok"));
  return rc;
}

#ifdef SQLITE_TEST

  /* If we compiled with the SQLITE_NO_SYNC flag, then syncing is a
  ** no-op
  */
#ifdef SQLITE_NO_SYNC
  return SQLITE_OK;
#else
  rc = osFlushFileBuffers(pFile->h);
  SimulateIOError( rc=FALSE );
  if( rc ){
    return SQLITE_OK;
  }else{
    pFile->lastErrno = osGetLastError();
    return winLogError(SQLITE_IOERR_FSYNC, pFile->lastErrno,
             "winSync", pFile->zPath);
  }
#endif
}

/*
** Determine the current size of a file in bytes
*/
static int winFileSize(sqlite3_file *id, sqlite3_int64 *pSize){
  DWORD upperBits;
  DWORD lowerBits;
  winFile *pFile = (winFile*)id;
  DWORD lastErrno;

  assert( id!=0 );
  SimulateIOError(return SQLITE_IOERR_FSTAT);
  lowerBits = osGetFileSize(pFile->h, &upperBits);
  if(   (lowerBits == INVALID_FILE_SIZE)
     && ((lastErrno = osGetLastError())!=NO_ERROR) )
  {
    pFile->lastErrno = lastErrno;
    return winLogError(SQLITE_IOERR_FSTAT, pFile->lastErrno,
             "winFileSize", pFile->zPath);
  }
  *pSize = (((sqlite3_int64)upperBits)<<32) + lowerBits;
  return SQLITE_OK;
}

/*
** LOCKFILE_FAIL_IMMEDIATELY is undefined on some Windows systems.
*/
#ifndef LOCKFILE_FAIL_IMMEDIATELY
# define LOCKFILE_FAIL_IMMEDIATELY 1
#endif

/*
** Acquire a reader lock.
** Different API routines are called depending on whether or not this
** is Win9x or WinNT.
*/
static int getReadLock(winFile *pFile){
  int res;
  if( isNT() ){
    OVERLAPPED ovlp;
    ovlp.Offset = SHARED_FIRST;
    ovlp.OffsetHigh = 0;
    ovlp.hEvent = 0;
    res = osLockFileEx(pFile->h, LOCKFILE_FAIL_IMMEDIATELY,
                       0, SHARED_SIZE, 0, &ovlp);
/* isNT() is 1 if SQLITE_OS_WINCE==1, so this else is never executed. 
*/
#if SQLITE_OS_WINCE==0
  }else{
    int lk;
    sqlite3_randomness(sizeof(lk), &lk);
    pFile->sharedLockByte = (short)((lk & 0x7fffffff)%(SHARED_SIZE - 1));
    res = osLockFile(pFile->h, SHARED_FIRST+pFile->sharedLockByte, 0, 1, 0);
#endif
  }
  if( res == 0 ){
    pFile->lastErrno = osGetLastError();
    /* No need to log a failure to lock */
  }
  return res;
}

/*
** Undo a readlock
*/
static int unlockReadLock(winFile *pFile){
  int res;
  DWORD lastErrno;
  if( isNT() ){
    res = osUnlockFile(pFile->h, SHARED_FIRST, 0, SHARED_SIZE, 0);
/* isNT() is 1 if SQLITE_OS_WINCE==1, so this else is never executed. 
*/
#if SQLITE_OS_WINCE==0
  }else{
    res = osUnlockFile(pFile->h, SHARED_FIRST + pFile->sharedLockByte, 0, 1, 0);
#endif
  }
  if( res==0 && ((lastErrno = osGetLastError())!=ERROR_NOT_LOCKED) ){
    pFile->lastErrno = lastErrno;
    winLogError(SQLITE_IOERR_UNLOCK, pFile->lastErrno,
             "unlockReadLock", pFile->zPath);
  }
  return res;
}

/*
** Lock the file with the lock specified by parameter locktype - one
** of the following:

** This routine will only increase a lock.  The winUnlock() routine
** erases all locks at once and returns us immediately to locking level 0.
** It is not possible to lower the locking level one step at a time.  You
** must go straight to locking level 0.
*/
static int winLock(sqlite3_file *id, int locktype){
  int rc = SQLITE_OK;    /* Return code from subroutines */
  int res = 1;           /* Result of a Windows lock call */
  int newLocktype;       /* Set pFile->locktype to this value before exiting */
  int gotPendingLock = 0;/* True if we acquired a PENDING lock this time */
  winFile *pFile = (winFile*)id;
  DWORD lastErrno = NO_ERROR;

  assert( id!=0 );
  OSTRACE(("LOCK %d %d was %d(%d)\n",
           pFile->h, locktype, pFile->locktype, pFile->sharedLockByte));

  /* If there is already a lock of this type or more restrictive on the
  ** OsFile, do nothing. Don't use the end_lock: exit path, as

  */
  newLocktype = pFile->locktype;
  if(   (pFile->locktype==NO_LOCK)
     || (   (locktype==EXCLUSIVE_LOCK)
         && (pFile->locktype==RESERVED_LOCK))
  ){
    int cnt = 3;
    while( cnt-->0 && (res = osLockFile(pFile->h, PENDING_BYTE, 0, 1, 0))==0 ){
      /* Try 3 times to get the pending lock.  This is needed to work
      ** around problems caused by indexing and/or anti-virus software on
      ** Windows systems.
      ** If you are using this code as a model for alternative VFSes, do not
      ** copy this retry logic.  It is a hack intended for Windows only.
      */
      OSTRACE(("could not get a PENDING lock. cnt=%d\n", cnt));
      if( cnt ) osSleep(1);
    }
    gotPendingLock = res;
    if( !res ){
      lastErrno = osGetLastError();
    }
  }

  /* Acquire a shared lock
  */
  if( locktype==SHARED_LOCK && res ){
    assert( pFile->locktype==NO_LOCK );
    res = getReadLock(pFile);
    if( res ){
      newLocktype = SHARED_LOCK;
    }else{
      lastErrno = osGetLastError();
    }
  }

  /* Acquire a RESERVED lock
  */
  if( locktype==RESERVED_LOCK && res ){
    assert( pFile->locktype==SHARED_LOCK );
    res = osLockFile(pFile->h, RESERVED_BYTE, 0, 1, 0);
    if( res ){
      newLocktype = RESERVED_LOCK;
    }else{
      lastErrno = osGetLastError();
    }
  }

  /* Acquire a PENDING lock
  */
  if( locktype==EXCLUSIVE_LOCK && res ){
    newLocktype = PENDING_LOCK;
    gotPendingLock = 0;
  }

  /* Acquire an EXCLUSIVE lock
  */
  if( locktype==EXCLUSIVE_LOCK && res ){
    assert( pFile->locktype>=SHARED_LOCK );
    res = unlockReadLock(pFile);
    OSTRACE(("unreadlock = %d\n", res));
    res = osLockFile(pFile->h, SHARED_FIRST, 0, SHARED_SIZE, 0);
    if( res ){
      newLocktype = EXCLUSIVE_LOCK;
    }else{
      lastErrno = osGetLastError();
      OSTRACE(("error-code = %d\n", lastErrno));
      getReadLock(pFile);
    }
  }

  /* If we are holding a PENDING lock that ought to be released, then
  ** release it now.
  */
  if( gotPendingLock && locktype==SHARED_LOCK ){
    osUnlockFile(pFile->h, PENDING_BYTE, 0, 1, 0);
  }

  /* Update the state of the lock has held in the file descriptor then
  ** return the appropriate result code.
  */
  if( res ){
    rc = SQLITE_OK;
  }else{
    OSTRACE(("LOCK FAILED %d trying for %d but got %d\n", pFile->h,
           locktype, newLocktype));
    pFile->lastErrno = lastErrno;
    rc = SQLITE_BUSY;
  }
  pFile->locktype = (u8)newLocktype;
  return rc;
}

/*

  SimulateIOError( return SQLITE_IOERR_CHECKRESERVEDLOCK; );

  assert( id!=0 );
  if( pFile->locktype>=RESERVED_LOCK ){
    rc = 1;
    OSTRACE(("TEST WR-LOCK %d %d (local)\n", pFile->h, rc));
  }else{
    rc = osLockFile(pFile->h, RESERVED_BYTE, 0, 1, 0);
    if( rc ){
      osUnlockFile(pFile->h, RESERVED_BYTE, 0, 1, 0);
    }
    rc = !rc;
    OSTRACE(("TEST WR-LOCK %d %d (remote)\n", pFile->h, rc));
  }
  *pResOut = rc;
  return SQLITE_OK;
}

  int rc = SQLITE_OK;
  assert( pFile!=0 );
  assert( locktype<=SHARED_LOCK );
  OSTRACE(("UNLOCK %d to %d was %d(%d)\n", pFile->h, locktype,
          pFile->locktype, pFile->sharedLockByte));
  type = pFile->locktype;
  if( type>=EXCLUSIVE_LOCK ){
    osUnlockFile(pFile->h, SHARED_FIRST, 0, SHARED_SIZE, 0);
    if( locktype==SHARED_LOCK && !getReadLock(pFile) ){
      /* This should never happen.  We should always be able to
      ** reacquire the read lock */
      rc = winLogError(SQLITE_IOERR_UNLOCK, osGetLastError(),
               "winUnlock", pFile->zPath);
    }
  }
  if( type>=RESERVED_LOCK ){
    osUnlockFile(pFile->h, RESERVED_BYTE, 0, 1, 0);
  }
  if( locktype==NO_LOCK && type>=SHARED_LOCK ){
    unlockReadLock(pFile);
  }
  if( type>=PENDING_LOCK ){
    osUnlockFile(pFile->h, PENDING_BYTE, 0, 1, 0);
  }
  pFile->locktype = (u8)locktype;
  return rc;
}

/*
** If *pArg is inititially negative then this is a query.  Set *pArg to
** 1 or 0 depending on whether or not bit mask of pFile->ctrlFlags is set.
**
** If *pArg is 0 or 1, then clear or set the mask bit of pFile->ctrlFlags.
*/
static void winModeBit(winFile *pFile, unsigned char mask, int *pArg){
  if( *pArg<0 ){
    *pArg = (pFile->ctrlFlags & mask)!=0;
  }else if( (*pArg)==0 ){
    pFile->ctrlFlags &= ~mask;
  }else{
    pFile->ctrlFlags |= mask;
  }
}

/*
** Control and query of the open file handle.
*/
static int winFileControl(sqlite3_file *id, int op, void *pArg){
  winFile *pFile = (winFile*)id;
  switch( op ){

          }
        }
        return rc;
      }
      return SQLITE_OK;
    }
    case SQLITE_FCNTL_PERSIST_WAL: {
      winModeBit(pFile, WINFILE_PERSIST_WAL, (int*)pArg);
      return SQLITE_OK;
    }
    case SQLITE_FCNTL_POWERSAFE_OVERWRITE: {
      winModeBit(pFile, WINFILE_PSOW, (int*)pArg);


      return SQLITE_OK;
    }
    case SQLITE_FCNTL_VFSNAME: {
      *(char**)pArg = sqlite3_mprintf("win32");
      return SQLITE_OK;
    }
    case SQLITE_FCNTL_SYNC_OMITTED: {
      return SQLITE_OK;
    }
    case SQLITE_FCNTL_WIN32_AV_RETRY: {
      int *a = (int*)pArg;

  return (int)(((winFile*)id)->sectorSize);
}

/*
** Return a vector of device characteristics.
*/
static int winDeviceCharacteristics(sqlite3_file *id){
  winFile *p = (winFile*)id;
  return SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN |
         ((p->ctrlFlags & WINFILE_PSOW)?SQLITE_IOCAP_POWERSAFE_OVERWRITE:0);
}

#ifndef SQLITE_OMIT_WAL

/* 
** Windows will only let you create file view mappings
** on allocation size granularity boundaries.

  if( lockType == _SHM_WRLCK ) dwFlags |= LOCKFILE_EXCLUSIVE_LOCK;

  memset(&ovlp, 0, sizeof(OVERLAPPED));
  ovlp.Offset = ofst;

  /* Release/Acquire the system-level lock */
  if( lockType==_SHM_UNLCK ){
    rc = osUnlockFileEx(pFile->hFile.h, 0, nByte, 0, &ovlp);
  }else{
    rc = osLockFileEx(pFile->hFile.h, dwFlags, 0, nByte, 0, &ovlp);
  }
  
  if( rc!= 0 ){
    rc = SQLITE_OK;
  }else{
    pFile->lastErrno =  osGetLastError();
    rc = SQLITE_BUSY;
  }

  OSTRACE(("SHM-LOCK %d %s %s 0x%08lx\n", 
           pFile->hFile.h,
           rc==SQLITE_OK ? "ok" : "failed",
           lockType==_SHM_UNLCK ? "UnlockFileEx" : "LockFileEx",

  assert( winShmMutexHeld() );
  pp = &winShmNodeList;
  while( (p = *pp)!=0 ){
    if( p->nRef==0 ){
      int i;
      if( p->mutex ) sqlite3_mutex_free(p->mutex);
      for(i=0; i<p->nRegion; i++){
        bRc = osUnmapViewOfFile(p->aRegion[i].pMap);
        OSTRACE(("SHM-PURGE pid-%d unmap region=%d %s\n",
                 (int)osGetCurrentProcessId(), i,
                 bRc ? "ok" : "failed"));
        bRc = osCloseHandle(p->aRegion[i].hMap);
        OSTRACE(("SHM-PURGE pid-%d close region=%d %s\n",
                 (int)osGetCurrentProcessId(), i,
                 bRc ? "ok" : "failed"));
      }
      if( p->hFile.h != INVALID_HANDLE_VALUE ){
        SimulateIOErrorBenign(1);
        winClose((sqlite3_file *)&p->hFile);
        SimulateIOErrorBenign(0);
      }

  assert( pDbFd->pShm==0 );    /* Not previously opened */

  /* Allocate space for the new sqlite3_shm object.  Also speculatively
  ** allocate space for a new winShmNode and filename.
  */
  p = sqlite3_malloc( sizeof(*p) );
  if( p==0 ) return SQLITE_IOERR_NOMEM;
  memset(p, 0, sizeof(*p));
  nName = sqlite3Strlen30(pDbFd->zPath);
  pNew = sqlite3_malloc( sizeof(*pShmNode) + nName + 15 );
  if( pNew==0 ){
    sqlite3_free(p);
    return SQLITE_IOERR_NOMEM;
  }
  memset(pNew, 0, sizeof(*pNew));
  pNew->zFilename = (char*)&pNew[1];
  sqlite3_snprintf(nName+15, pNew->zFilename, "%s-shm", pDbFd->zPath);
  sqlite3FileSuffix3(pDbFd->zPath, pNew->zFilename); 

  /* Look to see if there is an existing winShmNode that can be used.

    pNew = 0;
    ((winFile*)(&pShmNode->hFile))->h = INVALID_HANDLE_VALUE;
    pShmNode->pNext = winShmNodeList;
    winShmNodeList = pShmNode;

    pShmNode->mutex = sqlite3_mutex_alloc(SQLITE_MUTEX_FAST);
    if( pShmNode->mutex==0 ){
      rc = SQLITE_IOERR_NOMEM;
      goto shm_open_err;
    }

    rc = winOpen(pDbFd->pVfs,
                 pShmNode->zFilename,             /* Name of the file (UTF-8) */
                 (sqlite3_file*)&pShmNode->hFile,  /* File handle here */
                 SQLITE_OPEN_WAL | SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE, /* Mode flags */
                 0);
    if( SQLITE_OK!=rc ){
      rc = SQLITE_CANTOPEN_BKPT;
      goto shm_open_err;
    }

    /* Check to see if another process is holding the dead-man switch.
    ** If not, truncate the file to zero length. 
    */
    if( winShmSystemLock(pShmNode, _SHM_WRLCK, WIN_SHM_DMS, 1)==SQLITE_OK ){
      rc = winTruncate((sqlite3_file *)&pShmNode->hFile, 0);
      if( rc!=SQLITE_OK ){
        rc = winLogError(SQLITE_IOERR_SHMOPEN, osGetLastError(),
                 "winOpenShm", pDbFd->zPath);
      }
    }
    if( rc==SQLITE_OK ){
      winShmSystemLock(pShmNode, _SHM_UNLCK, WIN_SHM_DMS, 1);
      rc = winShmSystemLock(pShmNode, _SHM_RDLCK, WIN_SHM_DMS, 1);
    }
    if( rc ) goto shm_open_err;

        assert( (p->sharedMask & mask)==0 );
        p->exclMask |= mask;
      }
    }
  }
  sqlite3_mutex_leave(pShmNode->mutex);
  OSTRACE(("SHM-LOCK shmid-%d, pid-%d got %03x,%03x %s\n",
           p->id, (int)osGetCurrentProcessId(), p->sharedMask, p->exclMask,
           rc ? "failed" : "ok"));
  return rc;
}

/*
** Implement a memory barrier or memory fence on shared memory.  
**

    /* The requested region is not mapped into this processes address space.
    ** Check to see if it has been allocated (i.e. if the wal-index file is
    ** large enough to contain the requested region).
    */
    rc = winFileSize((sqlite3_file *)&pShmNode->hFile, &sz);
    if( rc!=SQLITE_OK ){
      rc = winLogError(SQLITE_IOERR_SHMSIZE, osGetLastError(),
               "winShmMap1", pDbFd->zPath);
      goto shmpage_out;
    }

    if( sz<nByte ){
      /* The requested memory region does not exist. If isWrite is set to
      ** zero, exit early. *pp will be set to NULL and SQLITE_OK returned.
      **
      ** Alternatively, if isWrite is non-zero, use ftruncate() to allocate
      ** the requested memory region.
      */
      if( !isWrite ) goto shmpage_out;
      rc = winTruncate((sqlite3_file *)&pShmNode->hFile, nByte);
      if( rc!=SQLITE_OK ){
        rc = winLogError(SQLITE_IOERR_SHMSIZE, osGetLastError(),
                 "winShmMap2", pDbFd->zPath);
        goto shmpage_out;
      }
    }

    /* Map the requested memory region into this processes address space. */
    apNew = (struct ShmRegion *)sqlite3_realloc(
        pShmNode->aRegion, (iRegion+1)*sizeof(apNew[0])
    );
    if( !apNew ){
      rc = SQLITE_IOERR_NOMEM;
      goto shmpage_out;
    }
    pShmNode->aRegion = apNew;

    while( pShmNode->nRegion<=iRegion ){
      HANDLE hMap;                /* file-mapping handle */
      void *pMap = 0;             /* Mapped memory region */
     
      hMap = osCreateFileMapping(pShmNode->hFile.h, 
          NULL, PAGE_READWRITE, 0, nByte, NULL
      );
      OSTRACE(("SHM-MAP pid-%d create region=%d nbyte=%d %s\n",
               (int)osGetCurrentProcessId(), pShmNode->nRegion, nByte,
               hMap ? "ok" : "failed"));
      if( hMap ){
        int iOffset = pShmNode->nRegion*szRegion;
        int iOffsetShift = iOffset % winSysInfo.dwAllocationGranularity;
        pMap = osMapViewOfFile(hMap, FILE_MAP_WRITE | FILE_MAP_READ,
            0, iOffset - iOffsetShift, szRegion + iOffsetShift
        );
        OSTRACE(("SHM-MAP pid-%d map region=%d offset=%d size=%d %s\n",
                 (int)osGetCurrentProcessId(), pShmNode->nRegion, iOffset,
                 szRegion, pMap ? "ok" : "failed"));
      }
      if( !pMap ){
        pShmNode->lastErrno = osGetLastError();
        rc = winLogError(SQLITE_IOERR_SHMMAP, pShmNode->lastErrno,
                 "winShmMap3", pDbFd->zPath);
        if( hMap ) osCloseHandle(hMap);
        goto shmpage_out;
      }

      pShmNode->aRegion[pShmNode->nRegion].pMap = pMap;
      pShmNode->aRegion[pShmNode->nRegion].hMap = hMap;
      pShmNode->nRegion++;
    }

  SimulateIOError( return SQLITE_IOERR );

  if( sqlite3_temp_directory ){
    sqlite3_snprintf(MAX_PATH-30, zTempPath, "%s", sqlite3_temp_directory);
  }else if( isNT() ){
    char *zMulti;
    WCHAR zWidePath[MAX_PATH];
    osGetTempPathW(MAX_PATH-30, zWidePath);
    zMulti = unicodeToUtf8(zWidePath);
    if( zMulti ){
      sqlite3_snprintf(MAX_PATH-30, zTempPath, "%s", zMulti);
      sqlite3_free(zMulti);
    }else{
      return SQLITE_IOERR_NOMEM;
    }
/* isNT() is 1 if SQLITE_OS_WINCE==1, so this else is never executed. 
** Since the ANSI version of these Windows API do not exist for WINCE,
** it's important to not reference them for WINCE builds.
*/
#if SQLITE_OS_WINCE==0
  }else{
    char *zUtf8;
    char zMbcsPath[MAX_PATH];
    osGetTempPathA(MAX_PATH-30, zMbcsPath);
    zUtf8 = sqlite3_win32_mbcs_to_utf8(zMbcsPath);
    if( zUtf8 ){
      sqlite3_snprintf(MAX_PATH-30, zTempPath, "%s", zUtf8);
      sqlite3_free(zUtf8);
    }else{
      return SQLITE_IOERR_NOMEM;
    }
#endif
  }

  /* Check that the output buffer is large enough for the temporary file 
  ** name. If it is not, return SQLITE_ERROR.
  */

  sqlite3_vfs *pVfs,        /* Not used */
  const char *zName,        /* Name of the file (UTF-8) */
  sqlite3_file *id,         /* Write the SQLite file handle here */
  int flags,                /* Open mode flags */
  int *pOutFlags            /* Status return flags */
){
  HANDLE h;
  DWORD lastErrno;
  DWORD dwDesiredAccess;
  DWORD dwShareMode;
  DWORD dwCreationDisposition;
  DWORD dwFlagsAndAttributes = 0;
#if SQLITE_OS_WINCE
  int isTemp = 0;
#endif

    }
    zUtf8Name = zTmpname;
  }

  /* Convert the filename to the system encoding. */
  zConverted = convertUtf8Filename(zUtf8Name);
  if( zConverted==0 ){
    return SQLITE_IOERR_NOMEM;
  }

  if( isReadWrite ){
    dwDesiredAccess = GENERIC_READ | GENERIC_WRITE;
  }else{
    dwDesiredAccess = GENERIC_READ;
  }

  /* Reports from the internet are that performance is always
  ** better if FILE_FLAG_RANDOM_ACCESS is used.  Ticket #2699. */
#if SQLITE_OS_WINCE
  dwFlagsAndAttributes |= FILE_FLAG_RANDOM_ACCESS;
#endif

  if( isNT() ){
    while( (h = osCreateFileW((LPCWSTR)zConverted,
                              dwDesiredAccess,
                              dwShareMode, NULL,
                              dwCreationDisposition,
                              dwFlagsAndAttributes,
                              NULL))==INVALID_HANDLE_VALUE &&
                              retryIoerr(&cnt, &lastErrno) ){}
/* isNT() is 1 if SQLITE_OS_WINCE==1, so this else is never executed. 
** Since the ANSI version of these Windows API do not exist for WINCE,
** it's important to not reference them for WINCE builds.
*/
#if SQLITE_OS_WINCE==0
  }else{
    while( (h = osCreateFileA((LPCSTR)zConverted,
                              dwDesiredAccess,
                              dwShareMode, NULL,
                              dwCreationDisposition,
                              dwFlagsAndAttributes,
                              NULL))==INVALID_HANDLE_VALUE &&
                              retryIoerr(&cnt, &lastErrno) ){}
#endif
  }

  logIoerr(cnt);

  OSTRACE(("OPEN %d %s 0x%lx %s\n", 
           h, zName, dwDesiredAccess, 
           h==INVALID_HANDLE_VALUE ? "failed" : "ok"));

  if( h==INVALID_HANDLE_VALUE ){
    pFile->lastErrno = lastErrno;
    winLogError(SQLITE_CANTOPEN, pFile->lastErrno, "winOpen", zUtf8Name);
    sqlite3_free(zConverted);
    if( isReadWrite && !isExclusive ){
      return winOpen(pVfs, zName, id, 
             ((flags|SQLITE_OPEN_READONLY)&~(SQLITE_OPEN_CREATE|SQLITE_OPEN_READWRITE)), pOutFlags);
    }else{
      return SQLITE_CANTOPEN_BKPT;
    }
  }

  memset(pFile, 0, sizeof(*pFile));
  pFile->pMethod = &winIoMethod;
  pFile->h = h;
  pFile->lastErrno = NO_ERROR;
  pFile->pVfs = pVfs;
  pFile->pShm = 0;
  pFile->zPath = zName;
  if( sqlite3_uri_boolean(zName, "psow", SQLITE_POWERSAFE_OVERWRITE) ){
    pFile->ctrlFlags |= WINFILE_PSOW;
  }
  pFile->sectorSize = getSectorSize(pVfs, zUtf8Name);

#if SQLITE_OS_WINCE
  if( isReadWrite && eType==SQLITE_OPEN_MAIN_DB
       && !winceCreateLock(zName, pFile)
  ){
    osCloseHandle(h);
    sqlite3_free(zConverted);
    return SQLITE_CANTOPEN_BKPT;
  }
  if( isTemp ){
    pFile->zDeleteOnClose = zConverted;
  }else
#endif
  {
    sqlite3_free(zConverted);
  }

  OpenCounter(+1);
  return rc;
}

/*
** Delete the named file.
**
** Note that Windows does not allow a file to be deleted if some other
** process has it open.  Sometimes a virus scanner or indexing program
** will open a journal file shortly after it is created in order to do
** whatever it does.  While this other process is holding the
** file open, we will be unable to delete it.  To work around this
** problem, we delay 100 milliseconds and try to delete again.  Up
** to MX_DELETION_ATTEMPTs deletion attempts are run before giving
** up and returning an error.
*/
static int winDelete(
  sqlite3_vfs *pVfs,          /* Not used on win32 */
  const char *zFilename,      /* Name of file to delete */
  int syncDir                 /* Not used on win32 */
){
  int cnt = 0;
  int rc;
  DWORD lastErrno;
  void *zConverted;
  UNUSED_PARAMETER(pVfs);
  UNUSED_PARAMETER(syncDir);

  SimulateIOError(return SQLITE_IOERR_DELETE);
  zConverted = convertUtf8Filename(zFilename);
  if( zConverted==0 ){
    return SQLITE_IOERR_NOMEM;
  }
  if( isNT() ){
    rc = 1;
    while( osGetFileAttributesW(zConverted)!=INVALID_FILE_ATTRIBUTES &&
         (rc = osDeleteFileW(zConverted))==0 && retryIoerr(&cnt, &lastErrno) ){}
    rc = rc ? SQLITE_OK : SQLITE_ERROR;
/* isNT() is 1 if SQLITE_OS_WINCE==1, so this else is never executed. 
** Since the ANSI version of these Windows API do not exist for WINCE,
** it's important to not reference them for WINCE builds.
*/
#if SQLITE_OS_WINCE==0
  }else{
    rc = 1;
    while( osGetFileAttributesA(zConverted)!=INVALID_FILE_ATTRIBUTES &&
         (rc = osDeleteFileA(zConverted))==0 && retryIoerr(&cnt, &lastErrno) ){}
    rc = rc ? SQLITE_OK : SQLITE_ERROR;
#endif
  }
  if( rc ){
    rc = winLogError(SQLITE_IOERR_DELETE, lastErrno,
             "winDelete", zFilename);
  }else{
    logIoerr(cnt);
  }
  sqlite3_free(zConverted);
  OSTRACE(("DELETE \"%s\" %s\n", zFilename, (rc ? "failed" : "ok" )));
  return rc;
}

/*
** Check the existance and status of a file.
*/
static int winAccess(
  sqlite3_vfs *pVfs,         /* Not used on win32 */
  const char *zFilename,     /* Name of file to check */
  int flags,                 /* Type of test to make on this file */
  int *pResOut               /* OUT: Result */
){
  DWORD attr;
  int rc = 0;
  DWORD lastErrno;
  void *zConverted;
  UNUSED_PARAMETER(pVfs);

  SimulateIOError( return SQLITE_IOERR_ACCESS; );
  zConverted = convertUtf8Filename(zFilename);
  if( zConverted==0 ){
    return SQLITE_IOERR_NOMEM;
  }
  if( isNT() ){
    int cnt = 0;
    WIN32_FILE_ATTRIBUTE_DATA sAttrData;
    memset(&sAttrData, 0, sizeof(sAttrData));
    while( !(rc = osGetFileAttributesExW((LPCWSTR)zConverted,
                             GetFileExInfoStandard, 
                             &sAttrData)) && retryIoerr(&cnt, &lastErrno) ){}
    if( rc ){
      /* For an SQLITE_ACCESS_EXISTS query, treat a zero-length file
      ** as if it does not exist.
      */
      if(    flags==SQLITE_ACCESS_EXISTS
          && sAttrData.nFileSizeHigh==0 
          && sAttrData.nFileSizeLow==0 ){
        attr = INVALID_FILE_ATTRIBUTES;
      }else{
        attr = sAttrData.dwFileAttributes;
      }
    }else{
      logIoerr(cnt);
      if( lastErrno!=ERROR_FILE_NOT_FOUND ){
        winLogError(SQLITE_IOERR_ACCESS, lastErrno, "winAccess", zFilename);
        sqlite3_free(zConverted);
        return SQLITE_IOERR_ACCESS;
      }else{
        attr = INVALID_FILE_ATTRIBUTES;
      }
    }
/* isNT() is 1 if SQLITE_OS_WINCE==1, so this else is never executed. 
** Since the ANSI version of these Windows API do not exist for WINCE,
** it's important to not reference them for WINCE builds.
*/
#if SQLITE_OS_WINCE==0
  }else{
    attr = osGetFileAttributesA((char*)zConverted);
#endif
  }
  sqlite3_free(zConverted);
  switch( flags ){
    case SQLITE_ACCESS_READ:
    case SQLITE_ACCESS_EXISTS:
      rc = attr!=INVALID_FILE_ATTRIBUTES;
      break;
    case SQLITE_ACCESS_READWRITE:
      rc = attr!=INVALID_FILE_ATTRIBUTES &&

  ** using the io-error infrastructure to test that SQLite handles this
  ** function failing. This function could fail if, for example, the
  ** current working directory has been unlinked.
  */
  SimulateIOError( return SQLITE_ERROR );
  UNUSED_PARAMETER(nFull);
  zConverted = convertUtf8Filename(zRelative);
  if( zConverted==0 ){
    return SQLITE_IOERR_NOMEM;
  }
  if( isNT() ){
    LPWSTR zTemp;
    nByte = osGetFullPathNameW((LPCWSTR)zConverted, 0, 0, 0) + 3;
    zTemp = sqlite3_malloc( nByte*sizeof(zTemp[0]) );
    if( zTemp==0 ){
      sqlite3_free(zConverted);
      return SQLITE_IOERR_NOMEM;
    }
    osGetFullPathNameW((LPCWSTR)zConverted, nByte, zTemp, 0);
    sqlite3_free(zConverted);
    zOut = unicodeToUtf8(zTemp);
    sqlite3_free(zTemp);
/* isNT() is 1 if SQLITE_OS_WINCE==1, so this else is never executed. 
** Since the ANSI version of these Windows API do not exist for WINCE,
** it's important to not reference them for WINCE builds.
*/
#if SQLITE_OS_WINCE==0
  }else{
    char *zTemp;
    nByte = osGetFullPathNameA((char*)zConverted, 0, 0, 0) + 3;
    zTemp = sqlite3_malloc( nByte*sizeof(zTemp[0]) );
    if( zTemp==0 ){
      sqlite3_free(zConverted);
      return SQLITE_IOERR_NOMEM;
    }
    osGetFullPathNameA((char*)zConverted, nByte, zTemp, 0);
    sqlite3_free(zConverted);
    zOut = sqlite3_win32_mbcs_to_utf8(zTemp);
    sqlite3_free(zTemp);
#endif
  }
  if( zOut ){
    sqlite3_snprintf(pVfs->mxPathname, zFull, "%s", zOut);
    sqlite3_free(zOut);
    return SQLITE_OK;
  }else{
    return SQLITE_IOERR_NOMEM;
  }
#endif
}

/*
** Get the sector size of the device used to store
** file.

  /*
  ** We need to get the full path name of the file
  ** to get the drive letter to look up the sector
  ** size.
  */
  SimulateIOErrorBenign(1);
  sqlite3BeginBenignMalloc();
  rc = winFullPathname(pVfs, zRelative, MAX_PATH, zFullpath);
  sqlite3EndBenignMalloc();
  SimulateIOErrorBenign(0);
  if( rc == SQLITE_OK )
  {
    void *zConverted;
    sqlite3BeginBenignMalloc();
    zConverted = convertUtf8Filename(zFullpath);
    sqlite3EndBenignMalloc();
    if( zConverted ){
      if( isNT() ){
        /* trim path to just drive reference */
        LPWSTR p = zConverted;
        for(;*p;p++){
          if( *p == '\\' ){
            *p = '\0';
            break;
          }
        }
        dwRet = osGetDiskFreeSpaceW((LPCWSTR)zConverted,
                                    &dwDummy,
                                    &bytesPerSector,
                                    &dwDummy,
                                    &dwDummy);
      }else{
        /* trim path to just drive reference */
        char *p = (char *)zConverted;
        for(;*p;p++){
          if( *p == '\\' ){
            *p = '\0';
            break;
          }
        }
        dwRet = osGetDiskFreeSpaceA((char*)zConverted,
                                    &dwDummy,
                                    &bytesPerSector,
                                    &dwDummy,
                                    &dwDummy);
      }
      sqlite3_free(zConverted);
    }
    if( !dwRet ){
      bytesPerSector = SQLITE_DEFAULT_SECTOR_SIZE;
    }
  }
#endif
  return (int) bytesPerSector; 

  HANDLE h;
  void *zConverted = convertUtf8Filename(zFilename);
  UNUSED_PARAMETER(pVfs);
  if( zConverted==0 ){
    return 0;
  }
  if( isNT() ){
    h = osLoadLibraryW((LPCWSTR)zConverted);
/* isNT() is 1 if SQLITE_OS_WINCE==1, so this else is never executed. 
** Since the ANSI version of these Windows API do not exist for WINCE,
** it's important to not reference them for WINCE builds.
*/
#if SQLITE_OS_WINCE==0
  }else{
    h = osLoadLibraryA((char*)zConverted);
#endif
  }
  sqlite3_free(zConverted);
  return (void*)h;
}
static void winDlError(sqlite3_vfs *pVfs, int nBuf, char *zBufOut){
  UNUSED_PARAMETER(pVfs);
  getLastErrorMsg(osGetLastError(), nBuf, zBufOut);
}
static void (*winDlSym(sqlite3_vfs *pVfs, void *pHandle, const char *zSymbol))(void){
  UNUSED_PARAMETER(pVfs);


  return (void(*)(void))osGetProcAddressA((HANDLE)pHandle, zSymbol);





}
static void winDlClose(sqlite3_vfs *pVfs, void *pHandle){
  UNUSED_PARAMETER(pVfs);
  osFreeLibrary((HANDLE)pHandle);
}
#else /* if SQLITE_OMIT_LOAD_EXTENSION is defined: */
  #define winDlOpen  0
  #define winDlError 0
  #define winDlSym   0
  #define winDlClose 0
#endif

  UNUSED_PARAMETER(pVfs);
#if defined(SQLITE_TEST)
  n = nBuf;
  memset(zBuf, 0, nBuf);
#else
  if( sizeof(SYSTEMTIME)<=nBuf-n ){
    SYSTEMTIME x;
    osGetSystemTime(&x);
    memcpy(&zBuf[n], &x, sizeof(x));
    n += sizeof(x);
  }
  if( sizeof(DWORD)<=nBuf-n ){
    DWORD pid = osGetCurrentProcessId();
    memcpy(&zBuf[n], &pid, sizeof(pid));
    n += sizeof(pid);
  }
  if( sizeof(DWORD)<=nBuf-n ){
    DWORD cnt = osGetTickCount();
    memcpy(&zBuf[n], &cnt, sizeof(cnt));
    n += sizeof(cnt);
  }
  if( sizeof(LARGE_INTEGER)<=nBuf-n ){
    LARGE_INTEGER i;
    osQueryPerformanceCounter(&i);
    memcpy(&zBuf[n], &i, sizeof(i));
    n += sizeof(i);
  }
#endif
  return n;
}


/*
** Sleep for a little while.  Return the amount of time slept.
*/
static int winSleep(sqlite3_vfs *pVfs, int microsec){
  osSleep((microsec+999)/1000);
  UNUSED_PARAMETER(pVfs);
  return ((microsec+999)/1000)*1000;
}

/*
** The following variable, if set to a non-zero value, is interpreted as
** the number of seconds since 1970 and is used to set the result of

#endif
  /* 2^32 - to avoid use of LL and warnings in gcc */
  static const sqlite3_int64 max32BitValue = 
      (sqlite3_int64)2000000000 + (sqlite3_int64)2000000000 + (sqlite3_int64)294967296;

#if SQLITE_OS_WINCE
  SYSTEMTIME time;
  osGetSystemTime(&time);
  /* if SystemTimeToFileTime() fails, it returns zero. */
  if (!osSystemTimeToFileTime(&time,&ft)){
    return SQLITE_ERROR;
  }
#else
  osGetSystemTimeAsFileTime( &ft );
#endif

  *piNow = winFiletimeEpoch +
            ((((sqlite3_int64)ft.dwHighDateTime)*max32BitValue) + 
               (sqlite3_int64)ft.dwLowDateTime)/(sqlite3_int64)10000;

#ifdef SQLITE_TEST

    *prNow = i/86400000.0;
  }
  return rc;
}

/*
** The idea is that this function works like a combination of
** GetLastError() and FormatMessage() on Windows (or errno and
** strerror_r() on Unix). After an error is returned by an OS
** function, SQLite calls this function with zBuf pointing to
** a buffer of nBuf bytes. The OS layer should populate the
** buffer with a nul-terminated UTF-8 encoded error message
** describing the last IO error to have occurred within the calling
** thread.
**
** If the error message is too large for the supplied buffer,

**
** However if an error message is supplied, it will be incorporated
** by sqlite into the error message available to the user using
** sqlite3_errmsg(), possibly making IO errors easier to debug.
*/
static int winGetLastError(sqlite3_vfs *pVfs, int nBuf, char *zBuf){
  UNUSED_PARAMETER(pVfs);
  return getLastErrorMsg(osGetLastError(), nBuf, zBuf);
}



/*
** Initialize and deinitialize the operating system interface.
*/
SQLITE_API int sqlite3_os_init(void){
  static sqlite3_vfs winVfs = {
    3,                   /* iVersion */

    winDlSym,            /* xDlSym */
    winDlClose,          /* xDlClose */
    winRandomness,       /* xRandomness */
    winSleep,            /* xSleep */
    winCurrentTime,      /* xCurrentTime */
    winGetLastError,     /* xGetLastError */
    winCurrentTimeInt64, /* xCurrentTimeInt64 */
    winSetSystemCall,    /* xSetSystemCall */
    winGetSystemCall,    /* xGetSystemCall */
    winNextSystemCall,   /* xNextSystemCall */
  };

  /* Double-check that the aSyscall[] array has been constructed
  ** correctly.  See ticket [bb3a86e890c8e96ab] */
  assert( ArraySize(aSyscall)==60 );

#ifndef SQLITE_OMIT_WAL
  /* get memory map allocation granularity */
  memset(&winSysInfo, 0, sizeof(SYSTEM_INFO));
  osGetSystemInfo(&winSysInfo);
  assert(winSysInfo.dwAllocationGranularity > 0);
#endif

  sqlite3_vfs_register(&winVfs, 1);
  return SQLITE_OK; 
}

SQLITE_API int sqlite3_os_end(void){ 
  return SQLITE_OK;
}

#endif /* SQLITE_OS_WIN */

/************** End of os_win.c **********************************************/

/*
** A complete page cache is an instance of this structure.
*/
struct PCache {
  PgHdr *pDirty, *pDirtyTail;         /* List of dirty pages in LRU order */
  PgHdr *pSynced;                     /* Last synced page in dirty page list */
  int nRef;                           /* Number of referenced pages */
  int szCache;                        /* Configured cache size */
  int szPage;                         /* Size of every page in this cache */
  int szExtra;                        /* Size of extra space for each page */
  int bPurgeable;                     /* True if pages are on backing store */
  int (*xStress)(void*,PgHdr*);       /* Call to try make a page clean */
  void *pStress;                      /* Argument to xStress */
  sqlite3_pcache *pCache;             /* Pluggable cache module */
  PgHdr *pPage1;                      /* Reference to page 1 */

*/
static void pcacheUnpin(PgHdr *p){
  PCache *pCache = p->pCache;
  if( pCache->bPurgeable ){
    if( p->pgno==1 ){
      pCache->pPage1 = 0;
    }
    sqlite3GlobalConfig.pcache2.xUnpin(pCache->pCache, p->pPage, 0);
  }
}

/*************************************************** General Interfaces ******
**
** Initialize and shutdown the page cache subsystem. Neither of these 
** functions are threadsafe.
*/
SQLITE_PRIVATE int sqlite3PcacheInitialize(void){
  if( sqlite3GlobalConfig.pcache2.xInit==0 ){
    /* IMPLEMENTATION-OF: R-26801-64137 If the xInit() method is NULL, then the
    ** built-in default page cache is used instead of the application defined
    ** page cache. */
    sqlite3PCacheSetDefault();
  }
  return sqlite3GlobalConfig.pcache2.xInit(sqlite3GlobalConfig.pcache2.pArg);
}
SQLITE_PRIVATE void sqlite3PcacheShutdown(void){
  if( sqlite3GlobalConfig.pcache2.xShutdown ){
    /* IMPLEMENTATION-OF: R-26000-56589 The xShutdown() method may be NULL. */
    sqlite3GlobalConfig.pcache2.xShutdown(sqlite3GlobalConfig.pcache2.pArg);
  }
}

/*
** Return the size in bytes of a PCache object.
*/
SQLITE_PRIVATE int sqlite3PcacheSize(void){ return sizeof(PCache); }

){
  memset(p, 0, sizeof(PCache));
  p->szPage = szPage;
  p->szExtra = szExtra;
  p->bPurgeable = bPurgeable;
  p->xStress = xStress;
  p->pStress = pStress;
  p->szCache = 100;
}

/*
** Change the page size for PCache object. The caller must ensure that there
** are no outstanding page references when this function is called.
*/
SQLITE_PRIVATE void sqlite3PcacheSetPageSize(PCache *pCache, int szPage){
  assert( pCache->nRef==0 && pCache->pDirty==0 );
  if( pCache->pCache ){
    sqlite3GlobalConfig.pcache2.xDestroy(pCache->pCache);
    pCache->pCache = 0;
    pCache->pPage1 = 0;
  }
  pCache->szPage = szPage;
}

/*
** Compute the number of pages of cache requested.
*/
static int numberOfCachePages(PCache *p){
  if( p->szCache>=0 ){
    return p->szCache;
  }else{
    return (-1024*p->szCache)/(p->szPage+p->szExtra);
  }
}

/*
** Try to obtain a page from the cache.
*/
SQLITE_PRIVATE int sqlite3PcacheFetch(
  PCache *pCache,       /* Obtain the page from this cache */
  Pgno pgno,            /* Page number to obtain */
  int createFlag,       /* If true, create page if it does not exist already */
  PgHdr **ppPage        /* Write the page here */
){
  sqlite3_pcache_page *pPage = 0;
  PgHdr *pPgHdr = 0;
  int eCreate;

  assert( pCache!=0 );
  assert( createFlag==1 || createFlag==0 );
  assert( pgno>0 );

  /* If the pluggable cache (sqlite3_pcache*) has not been allocated,
  ** allocate it now.
  */
  if( !pCache->pCache && createFlag ){
    sqlite3_pcache *p;


    p = sqlite3GlobalConfig.pcache2.xCreate(
        pCache->szPage, pCache->szExtra + sizeof(PgHdr), pCache->bPurgeable
    );
    if( !p ){
      return SQLITE_NOMEM;
    }
    sqlite3GlobalConfig.pcache2.xCachesize(p, numberOfCachePages(pCache));
    pCache->pCache = p;
  }

  eCreate = createFlag * (1 + (!pCache->bPurgeable || !pCache->pDirty));
  if( pCache->pCache ){
    pPage = sqlite3GlobalConfig.pcache2.xFetch(pCache->pCache, pgno, eCreate);
  }

  if( !pPage && eCreate==1 ){
    PgHdr *pPg;

    /* Find a dirty page to write-out and recycle. First try to find a 
    ** page that does not require a journal-sync (one with PGHDR_NEED_SYNC

    if( pPg ){
      int rc;
#ifdef SQLITE_LOG_CACHE_SPILL
      sqlite3_log(SQLITE_FULL, 
                  "spill page %d making room for %d - cache used: %d/%d",
                  pPg->pgno, pgno,
                  sqlite3GlobalConfig.pcache.xPagecount(pCache->pCache),
                  numberOfCachePages(pCache));
#endif
      rc = pCache->xStress(pCache->pStress, pPg);
      if( rc!=SQLITE_OK && rc!=SQLITE_BUSY ){
        return rc;
      }
    }

    pPage = sqlite3GlobalConfig.pcache2.xFetch(pCache->pCache, pgno, 2);
  }

  if( pPage ){
    pPgHdr = (PgHdr *)pPage->pExtra;

    if( !pPgHdr->pPage ){
      memset(pPgHdr, 0, sizeof(PgHdr));
      pPgHdr->pPage = pPage;
      pPgHdr->pData = pPage->pBuf;
      pPgHdr->pExtra = (void *)&pPgHdr[1];
      memset(pPgHdr->pExtra, 0, pCache->szExtra);
      pPgHdr->pCache = pCache;
      pPgHdr->pgno = pgno;
    }
    assert( pPgHdr->pCache==pCache );
    assert( pPgHdr->pgno==pgno );
    assert( pPgHdr->pData==pPage->pBuf );
    assert( pPgHdr->pExtra==(void *)&pPgHdr[1] );

    if( 0==pPgHdr->nRef ){
      pCache->nRef++;
    }
    pPgHdr->nRef++;
    if( pgno==1 ){
      pCache->pPage1 = pPgHdr;
    }
  }
  *ppPage = pPgHdr;
  return (pPgHdr==0 && eCreate) ? SQLITE_NOMEM : SQLITE_OK;
}

/*
** Decrement the reference count on a page. If the page is clean and the
** reference count drops to 0, then it is made elible for recycling.
*/
SQLITE_PRIVATE void sqlite3PcacheRelease(PgHdr *p){

    pcacheRemoveFromDirtyList(p);
  }
  pCache = p->pCache;
  pCache->nRef--;
  if( p->pgno==1 ){
    pCache->pPage1 = 0;
  }
  sqlite3GlobalConfig.pcache2.xUnpin(pCache->pCache, p->pPage, 1);
}

/*
** Make sure the page is marked as dirty. If it isn't dirty already,
** make it so.
*/
SQLITE_PRIVATE void sqlite3PcacheMakeDirty(PgHdr *p){

/*
** Change the page number of page p to newPgno. 
*/
SQLITE_PRIVATE void sqlite3PcacheMove(PgHdr *p, Pgno newPgno){
  PCache *pCache = p->pCache;
  assert( p->nRef>0 );
  assert( newPgno>0 );
  sqlite3GlobalConfig.pcache2.xRekey(pCache->pCache, p->pPage, p->pgno,newPgno);
  p->pgno = newPgno;
  if( (p->flags&PGHDR_DIRTY) && (p->flags&PGHDR_NEED_SYNC) ){
    pcacheRemoveFromDirtyList(p);
    pcacheAddToDirtyList(p);
  }
}

        sqlite3PcacheMakeClean(p);
      }
    }
    if( pgno==0 && pCache->pPage1 ){
      memset(pCache->pPage1->pData, 0, pCache->szPage);
      pgno = 1;
    }
    sqlite3GlobalConfig.pcache2.xTruncate(pCache->pCache, pgno+1);
  }
}

/*
** Close a cache.
*/
SQLITE_PRIVATE void sqlite3PcacheClose(PCache *pCache){
  if( pCache->pCache ){
    sqlite3GlobalConfig.pcache2.xDestroy(pCache->pCache);
  }
}

/* 
** Discard the contents of the cache.
*/
SQLITE_PRIVATE void sqlite3PcacheClear(PCache *pCache){

/* 
** Return the total number of pages in the cache.
*/
SQLITE_PRIVATE int sqlite3PcachePagecount(PCache *pCache){
  int nPage = 0;
  if( pCache->pCache ){
    nPage = sqlite3GlobalConfig.pcache2.xPagecount(pCache->pCache);
  }
  return nPage;
}

#ifdef SQLITE_TEST
/*
** Get the suggested cache-size value.
*/
SQLITE_PRIVATE int sqlite3PcacheGetCachesize(PCache *pCache){
  return numberOfCachePages(pCache);
}
#endif

/*
** Set the suggested cache-size value.
*/
SQLITE_PRIVATE void sqlite3PcacheSetCachesize(PCache *pCache, int mxPage){
  pCache->szCache = mxPage;
  if( pCache->pCache ){
    sqlite3GlobalConfig.pcache2.xCachesize(pCache->pCache,
                                           numberOfCachePages(pCache));
  }
}

/*
** Free up as much memory as possible from the page cache.
*/
SQLITE_PRIVATE void sqlite3PcacheShrink(PCache *pCache){
  if( pCache->pCache ){
    sqlite3GlobalConfig.pcache2.xShrink(pCache->pCache);
  }
}

#if defined(SQLITE_CHECK_PAGES) || defined(SQLITE_DEBUG)
/*
** For all dirty pages currently in the cache, invoke the specified
** callback. This is only used if the SQLITE_CHECK_PAGES macro is

*/


typedef struct PCache1 PCache1;
typedef struct PgHdr1 PgHdr1;
typedef struct PgFreeslot PgFreeslot;
typedef struct PGroup PGroup;


/* Each page cache (or PCache) belongs to a PGroup.  A PGroup is a set 
** of one or more PCaches that are able to recycle each others unpinned
** pages when they are under memory pressure.  A PGroup is an instance of
** the following object.
**
** This page cache implementation works in one of two modes:

  /* Cache configuration parameters. Page size (szPage) and the purgeable
  ** flag (bPurgeable) are set when the cache is created. nMax may be 
  ** modified at any time by a call to the pcache1CacheSize() method.
  ** The PGroup mutex must be held when accessing nMax.
  */
  PGroup *pGroup;                     /* PGroup this cache belongs to */
  int szPage;                         /* Size of allocated pages in bytes */
  int szExtra;                        /* Size of extra space in bytes */
  int bPurgeable;                     /* True if cache is purgeable */
  unsigned int nMin;                  /* Minimum number of pages reserved */
  unsigned int nMax;                  /* Configured "cache_size" value */
  unsigned int n90pct;                /* nMax*9/10 */

  /* Hash table of all pages. The following variables may only be accessed
  ** when the accessor is holding the PGroup mutex.
  */
  unsigned int nRecyclable;           /* Number of pages in the LRU list */
  unsigned int nPage;                 /* Total number of pages in apHash */
  unsigned int nHash;                 /* Number of slots in apHash[] */
  PgHdr1 **apHash;                    /* Hash table for fast lookup by key */

  unsigned int iMaxKey;               /* Largest key seen since xTruncate() */
};

/*
** Each cache entry is represented by an instance of the following 
** structure. Unless SQLITE_PCACHE_SEPARATE_HEADER is defined, a buffer of
** PgHdr1.pCache->szPage bytes is allocated directly before this structure 
** in memory.

*/
struct PgHdr1 {
  sqlite3_pcache_page page;
  unsigned int iKey;             /* Key value (page number) */
  PgHdr1 *pNext;                 /* Next in hash table chain */
  PCache1 *pCache;               /* Cache that currently owns this page */
  PgHdr1 *pLruNext;              /* Next in LRU list of unpinned pages */
  PgHdr1 *pLruPrev;              /* Previous in LRU list of unpinned pages */
};

/*
** All code in this file should access the global structure above via the
** alias "pcache1". This ensures that the WSD emulation is used when
** compiling for systems that do not support real WSD.
*/
#define pcache1 (GLOBAL(struct PCacheGlobal, pcache1_g))
















/*
** Macros to enter and leave the PCache LRU mutex.
*/
#define pcache1EnterMutex(X) sqlite3_mutex_enter((X)->mutex)
#define pcache1LeaveMutex(X) sqlite3_mutex_leave((X)->mutex)

/******************************************************************************/

  }
  return p;
}

/*
** Free an allocated buffer obtained from pcache1Alloc().
*/
static int pcache1Free(void *p){
  int nFreed = 0;
  if( p==0 ) return 0;
  if( p>=pcache1.pStart && p<pcache1.pEnd ){
    PgFreeslot *pSlot;
    sqlite3_mutex_enter(pcache1.mutex);
    sqlite3StatusAdd(SQLITE_STATUS_PAGECACHE_USED, -1);
    pSlot = (PgFreeslot*)p;
    pSlot->pNext = pcache1.pFree;
    pcache1.pFree = pSlot;
    pcache1.nFreeSlot++;
    pcache1.bUnderPressure = pcache1.nFreeSlot<pcache1.nReserve;
    assert( pcache1.nFreeSlot<=pcache1.nSlot );
    sqlite3_mutex_leave(pcache1.mutex);
  }else{

    assert( sqlite3MemdebugHasType(p, MEMTYPE_PCACHE) );
    sqlite3MemdebugSetType(p, MEMTYPE_HEAP);
    nFreed = sqlite3MallocSize(p);
    sqlite3_mutex_enter(pcache1.mutex);
    sqlite3StatusAdd(SQLITE_STATUS_PAGECACHE_OVERFLOW, -nFreed);
    sqlite3_mutex_leave(pcache1.mutex);
    sqlite3_free(p);
  }
  return nFreed;
}

#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
/*
** Return the size of a pcache allocation
*/
static int pcache1MemSize(void *p){

}
#endif /* SQLITE_ENABLE_MEMORY_MANAGEMENT */

/*
** Allocate a new page object initially associated with cache pCache.
*/
static PgHdr1 *pcache1AllocPage(PCache1 *pCache){

  PgHdr1 *p = 0;
  void *pPg;

  /* The group mutex must be released before pcache1Alloc() is called. This
  ** is because it may call sqlite3_release_memory(), which assumes that 
  ** this mutex is not held. */
  assert( sqlite3_mutex_held(pCache->pGroup->mutex) );
  pcache1LeaveMutex(pCache->pGroup);
#ifdef SQLITE_PCACHE_SEPARATE_HEADER
  pPg = pcache1Alloc(pCache->szPage);
  p = sqlite3Malloc(sizeof(PgHdr1) + pCache->szExtra);
  if( !pPg || !p ){
    pcache1Free(pPg);
    sqlite3_free(p);
    pPg = 0;
  }
#else
  pPg = pcache1Alloc(sizeof(PgHdr1) + pCache->szPage + pCache->szExtra);
  p = (PgHdr1 *)&((u8 *)pPg)[pCache->szPage];
#endif
  pcache1EnterMutex(pCache->pGroup);

  if( pPg ){
    p->page.pBuf = pPg;
    p->page.pExtra = &p[1];
    if( pCache->bPurgeable ){
      pCache->pGroup->nCurrentPage++;
    }
    return p;
  }
  return 0;
}

/*
** Free a page object allocated by pcache1AllocPage().
**
** The pointer is allowed to be NULL, which is prudent.  But it turns out
** that the current implementation happens to never call this routine
** with a NULL pointer, so we mark the NULL test with ALWAYS().
*/
static void pcache1FreePage(PgHdr1 *p){
  if( ALWAYS(p) ){
    PCache1 *pCache = p->pCache;
    assert( sqlite3_mutex_held(p->pCache->pGroup->mutex) );
    pcache1Free(p->page.pBuf);
#ifdef SQLITE_PCACHE_SEPARATE_HEADER
    sqlite3_free(p);
#endif
    if( pCache->bPurgeable ){
      pCache->pGroup->nCurrentPage--;
    }
  }
}

/*

**
** Or, the heap is used for all page cache memory put the heap is
** under memory pressure, then again it is desirable to avoid
** allocating a new page cache entry in order to avoid stressing
** the heap even further.
*/
static int pcache1UnderMemoryPressure(PCache1 *pCache){
  if( pcache1.nSlot && (pCache->szPage+pCache->szExtra)<=pcache1.szSlot ){
    return pcache1.bUnderPressure;
  }else{
    return sqlite3HeapNearlyFull();
  }
}

/******************************************************************************/

}

/*
** Implementation of the sqlite3_pcache.xCreate method.
**
** Allocate a new cache.
*/
static sqlite3_pcache *pcache1Create(int szPage, int szExtra, int bPurgeable){
  PCache1 *pCache;      /* The newly created page cache */
  PGroup *pGroup;       /* The group the new page cache will belong to */
  int sz;               /* Bytes of memory required to allocate the new cache */

  /*
  ** The seperateCache variable is true if each PCache has its own private
  ** PGroup.  In other words, separateCache is true for mode (1) where no

  **      use separate caches (mode-1)
  */
#if defined(SQLITE_ENABLE_MEMORY_MANAGEMENT) || SQLITE_THREADSAFE==0
  const int separateCache = 0;
#else
  int separateCache = sqlite3GlobalConfig.bCoreMutex>0;
#endif

  assert( (szPage & (szPage-1))==0 && szPage>=512 && szPage<=65536 );
  assert( szExtra < 300 );

  sz = sizeof(PCache1) + sizeof(PGroup)*separateCache;
  pCache = (PCache1 *)sqlite3_malloc(sz);
  if( pCache ){
    memset(pCache, 0, sz);
    if( separateCache ){
      pGroup = (PGroup*)&pCache[1];
      pGroup->mxPinned = 10;
    }else{
      pGroup = &pcache1.grp;
    }
    pCache->pGroup = pGroup;
    pCache->szPage = szPage;
    pCache->szExtra = szExtra;
    pCache->bPurgeable = (bPurgeable ? 1 : 0);
    if( bPurgeable ){
      pCache->nMin = 10;
      pcache1EnterMutex(pGroup);
      pGroup->nMinPage += pCache->nMin;
      pGroup->mxPinned = pGroup->nMaxPage + 10 - pGroup->nMinPage;
      pcache1LeaveMutex(pGroup);

    pGroup->mxPinned = pGroup->nMaxPage + 10 - pGroup->nMinPage;
    pCache->nMax = nMax;
    pCache->n90pct = pCache->nMax*9/10;
    pcache1EnforceMaxPage(pGroup);
    pcache1LeaveMutex(pGroup);
  }
}

/*
** Implementation of the sqlite3_pcache.xShrink method. 
**
** Free up as much memory as possible.
*/
static void pcache1Shrink(sqlite3_pcache *p){
  PCache1 *pCache = (PCache1*)p;
  if( pCache->bPurgeable ){
    PGroup *pGroup = pCache->pGroup;
    int savedMaxPage;
    pcache1EnterMutex(pGroup);
    savedMaxPage = pGroup->nMaxPage;
    pGroup->nMaxPage = 0;
    pcache1EnforceMaxPage(pGroup);
    pGroup->nMaxPage = savedMaxPage;
    pcache1LeaveMutex(pGroup);
  }
}

/*
** Implementation of the sqlite3_pcache.xPagecount method. 
*/
static int pcache1Pagecount(sqlite3_pcache *p){
  int n;
  PCache1 *pCache = (PCache1*)p;

**
**      then attempt to recycle a page from the LRU list. If it is the right
**      size, return the recycled buffer. Otherwise, free the buffer and
**      proceed to step 5. 
**
**   5. Otherwise, allocate and return a new page buffer.
*/
static sqlite3_pcache_page *pcache1Fetch(
  sqlite3_pcache *p, 
  unsigned int iKey, 
  int createFlag
){
  int nPinned;
  PCache1 *pCache = (PCache1 *)p;
  PGroup *pGroup;
  PgHdr1 *pPage = 0;

  assert( pCache->bPurgeable || createFlag!=1 );
  assert( pCache->bPurgeable || pCache->nMin==0 );

  ** optimization:  The common case is to exit the module before reaching
  ** this point.
  */
#ifdef SQLITE_MUTEX_OMIT
  pGroup = pCache->pGroup;
#endif


  /* Step 3: Abort if createFlag is 1 but the cache is nearly full */
  nPinned = pCache->nPage - pCache->nRecyclable;
  assert( nPinned>=0 );
  assert( pGroup->mxPinned == pGroup->nMaxPage + 10 - pGroup->nMinPage );
  assert( pCache->n90pct == pCache->nMax*9/10 );
  if( createFlag==1 && (
        nPinned>=pGroup->mxPinned

  /* Step 4. Try to recycle a page. */
  if( pCache->bPurgeable && pGroup->pLruTail && (
         (pCache->nPage+1>=pCache->nMax)
      || pGroup->nCurrentPage>=pGroup->nMaxPage
      || pcache1UnderMemoryPressure(pCache)
  )){
    PCache1 *pOther;
    pPage = pGroup->pLruTail;
    pcache1RemoveFromHash(pPage);
    pcache1PinPage(pPage);
    pOther = pPage->pCache;

    /* We want to verify that szPage and szExtra are the same for pOther
    ** and pCache.  Assert that we can verify this by comparing sums. */
    assert( (pCache->szPage & (pCache->szPage-1))==0 && pCache->szPage>=512 );
    assert( pCache->szExtra<512 );
    assert( (pOther->szPage & (pOther->szPage-1))==0 && pOther->szPage>=512 );
    assert( pOther->szExtra<512 );

    if( pOther->szPage+pOther->szExtra != pCache->szPage+pCache->szExtra ){
      pcache1FreePage(pPage);
      pPage = 0;
    }else{
      pGroup->nCurrentPage -= (pOther->bPurgeable - pCache->bPurgeable);

    }
  }

  /* Step 5. If a usable page buffer has still not been found, 
  ** attempt to allocate a new one. 
  */
  if( !pPage ){
    if( createFlag==1 ) sqlite3BeginBenignMalloc();
    pPage = pcache1AllocPage(pCache);
    if( createFlag==1 ) sqlite3EndBenignMalloc();
  }

  if( pPage ){
    unsigned int h = iKey % pCache->nHash;
    pCache->nPage++;
    pPage->iKey = iKey;
    pPage->pNext = pCache->apHash[h];
    pPage->pCache = pCache;
    pPage->pLruPrev = 0;
    pPage->pLruNext = 0;
    *(void **)pPage->page.pExtra = 0;
    pCache->apHash[h] = pPage;
  }

fetch_out:
  if( pPage && iKey>pCache->iMaxKey ){
    pCache->iMaxKey = iKey;
  }
  pcache1LeaveMutex(pGroup);
  return &pPage->page;
}


/*
** Implementation of the sqlite3_pcache.xUnpin method.
**
** Mark a page as unpinned (eligible for asynchronous recycling).
*/
static void pcache1Unpin(
  sqlite3_pcache *p, 
  sqlite3_pcache_page *pPg, 
  int reuseUnlikely
){
  PCache1 *pCache = (PCache1 *)p;
  PgHdr1 *pPage = (PgHdr1 *)pPg;
  PGroup *pGroup = pCache->pGroup;
 
  assert( pPage->pCache==pCache );
  pcache1EnterMutex(pGroup);

  /* It is an error to call this function if the page is already 
  ** part of the PGroup LRU list.

}

/*
** Implementation of the sqlite3_pcache.xRekey method. 
*/
static void pcache1Rekey(
  sqlite3_pcache *p,
  sqlite3_pcache_page *pPg,
  unsigned int iOld,
  unsigned int iNew
){
  PCache1 *pCache = (PCache1 *)p;
  PgHdr1 *pPage = (PgHdr1 *)pPg;
  PgHdr1 **pp;
  unsigned int h; 
  assert( pPage->iKey==iOld );
  assert( pPage->pCache==pCache );

  pcache1EnterMutex(pCache->pGroup);

/*
** This function is called during initialization (sqlite3_initialize()) to
** install the default pluggable cache module, assuming the user has not
** already provided an alternative.
*/
SQLITE_PRIVATE void sqlite3PCacheSetDefault(void){
  static const sqlite3_pcache_methods2 defaultMethods = {
    1,                       /* iVersion */
    0,                       /* pArg */
    pcache1Init,             /* xInit */
    pcache1Shutdown,         /* xShutdown */
    pcache1Create,           /* xCreate */
    pcache1Cachesize,        /* xCachesize */
    pcache1Pagecount,        /* xPagecount */
    pcache1Fetch,            /* xFetch */
    pcache1Unpin,            /* xUnpin */
    pcache1Rekey,            /* xRekey */
    pcache1Truncate,         /* xTruncate */
    pcache1Destroy,          /* xDestroy */
    pcache1Shrink            /* xShrink */
  };
  sqlite3_config(SQLITE_CONFIG_PCACHE2, &defaultMethods);
}

#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
/*
** This function is called to free superfluous dynamically allocated memory
** held by the pager system. Memory in use by any SQLite pager allocated
** by the current thread may be sqlite3_free()ed.
**
** nReq is the number of bytes of memory required. Once this much has
** been released, the function returns. The return value is the total number 
** of bytes of memory released.
*/
SQLITE_PRIVATE int sqlite3PcacheReleaseMemory(int nReq){
  int nFree = 0;
  assert( sqlite3_mutex_notheld(pcache1.grp.mutex) );
  assert( sqlite3_mutex_notheld(pcache1.mutex) );
  if( pcache1.pStart==0 ){
    PgHdr1 *p;
    pcache1EnterMutex(&pcache1.grp);
    while( (nReq<0 || nFree<nReq) && ((p=pcache1.grp.pLruTail)!=0) ){
      nFree += pcache1MemSize(p->page.pBuf);
#ifdef SQLITE_PCACHE_SEPARATE_HEADER
      nFree += sqlite3MemSize(p);
#endif
      pcache1PinPage(p);
      pcache1RemoveFromHash(p);
      pcache1FreePage(p);
    }
    pcache1LeaveMutex(&pcache1.grp);
  }
  return nFree;

/* Move the write position of the WAL back to iFrame.  Called in
** response to a ROLLBACK TO command. */
SQLITE_PRIVATE int sqlite3WalSavepointUndo(Wal *pWal, u32 *aWalData);

/* Write a frame or frames to the log. */
SQLITE_PRIVATE int sqlite3WalFrames(Wal *pWal, int, PgHdr *, Pgno, int, int);

/* Additional values that can be added to the sync_flags argument of
** sqlite3WalFrames():
*/
#define WAL_SYNC_TRANSACTIONS  0x20   /* Sync at the end of each transaction */
#define SQLITE_SYNC_MASK       0x13   /* Mask off the SQLITE_SYNC_* values */

/* Copy pages from the log to the database file */ 
SQLITE_PRIVATE int sqlite3WalCheckpoint(
  Wal *pWal,                      /* Write-ahead log connection */
  int eMode,                      /* One of PASSIVE, FULL and RESTART */
  int (*xBusy)(void*),            /* Function to call when busy */
  void *pBusyArg,                 /* Context argument for xBusyHandler */
  int sync_flags,                 /* Flags to sync db file with (or 0) */

  u8 exclusiveMode;           /* Boolean. True if locking_mode==EXCLUSIVE */
  u8 journalMode;             /* One of the PAGER_JOURNALMODE_* values */
  u8 useJournal;              /* Use a rollback journal on this file */
  u8 noReadlock;              /* Do not bother to obtain readlocks */
  u8 noSync;                  /* Do not sync the journal if true */
  u8 fullSync;                /* Do extra syncs of the journal for robustness */
  u8 ckptSyncFlags;           /* SYNC_NORMAL or SYNC_FULL for checkpoint */
  u8 walSyncFlags;            /* SYNC_NORMAL or SYNC_FULL for wal writes */
  u8 syncFlags;               /* SYNC_NORMAL or SYNC_FULL otherwise */
  u8 tempFile;                /* zFilename is a temporary file */
  u8 readOnly;                /* True for a read-only database */
  u8 memDb;                   /* True to inhibit all file I/O */

  /**************************************************************************
  ** The following block contains those class members that change during

#ifndef SQLITE_OMIT_WAL
static int pagerUseWal(Pager *pPager){
  return (pPager->pWal!=0);
}
#else
# define pagerUseWal(x) 0
# define pagerRollbackWal(x) 0
# define pagerWalFrames(v,w,x,y) 0
# define pagerOpenWalIfPresent(z) SQLITE_OK
# define pagerBeginReadTransaction(z) SQLITE_OK
#endif

#ifndef NDEBUG 
/*
** Usage:

**
** For temporary files the effective sector size is always 512 bytes.
**
** Otherwise, for non-temporary files, the effective sector size is
** the value returned by the xSectorSize() method rounded up to 32 if
** it is less than 32, or rounded down to MAX_SECTOR_SIZE if it
** is greater than MAX_SECTOR_SIZE.
**
** If the file has the SQLITE_IOCAP_POWERSAFE_OVERWRITE property, then set
** the effective sector size to its minimum value (512).  The purpose of
** pPager->sectorSize is to define the "blast radius" of bytes that
** might change if a crash occurs while writing to a single byte in
** that range.  But with POWERSAFE_OVERWRITE, the blast radius is zero
** (that is what POWERSAFE_OVERWRITE means), so we minimize the sector
** size.  For backwards compatibility of the rollback journal file format,
** we cannot reduce the effective sector size below 512.
*/
static void setSectorSize(Pager *pPager){
  assert( isOpen(pPager->fd) || pPager->tempFile );

  if( pPager->tempFile
   || (sqlite3OsDeviceCharacteristics(pPager->fd) & 
              SQLITE_IOCAP_POWERSAFE_OVERWRITE)!=0
  ){
    /* Sector size doesn't matter for temporary files. Also, the file
    ** may not have been opened yet, in which case the OsSectorSize()
    ** call will segfault. */

    pPager->sectorSize = 512;
  }else{
    pPager->sectorSize = sqlite3OsSectorSize(pPager->fd);
    if( pPager->sectorSize<32 ){
      pPager->sectorSize = 512;
    }
    if( pPager->sectorSize>MAX_SECTOR_SIZE ){
      assert( MAX_SECTOR_SIZE>=512 );
      pPager->sectorSize = MAX_SECTOR_SIZE;
    }
  }
}

/*
** Playback the journal and thus restore the database file to
** the state it was in before we started making changes.  
**

** The list of pages passed into this routine is always sorted by page number.
** Hence, if page 1 appears anywhere on the list, it will be the first page.
*/ 
static int pagerWalFrames(
  Pager *pPager,                  /* Pager object */
  PgHdr *pList,                   /* List of frames to log */
  Pgno nTruncate,                 /* Database size after this commit */
  int isCommit                    /* True if this is a commit */

){
  int rc;                         /* Return code */
#if defined(SQLITE_DEBUG) || defined(SQLITE_CHECK_PAGES)
  PgHdr *p;                       /* For looping over pages */
#endif

  assert( pPager->pWal );

      if( p->pgno<=nTruncate ) ppNext = &p->pDirty;
    }
    assert( pList );
  }

  if( pList->pgno==1 ) pager_write_changecounter(pList);
  rc = sqlite3WalFrames(pPager->pWal, 
      pPager->pageSize, pList, nTruncate, isCommit, pPager->walSyncFlags
  );
  if( rc==SQLITE_OK && pPager->pBackup ){
    PgHdr *p;
    for(p=pList; p; p=p->pDirty){
      sqlite3BackupUpdate(pPager->pBackup, p->pgno, (u8 *)p->pData);
    }
  }

  /* Finally,  rollback pages from the sub-journal.  Page that were
  ** previously rolled back out of the main journal (and are hence in pDone)
  ** will be skipped.  Out-of-range pages are also skipped.
  */
  if( pSavepoint ){
    u32 ii;            /* Loop counter */
    i64 offset = (i64)pSavepoint->iSubRec*(4+pPager->pageSize);

    if( pagerUseWal(pPager) ){
      rc = sqlite3WalSavepointUndo(pPager->pWal, pSavepoint->aWalData);
    }
    for(ii=pSavepoint->iSubRec; rc==SQLITE_OK && ii<pPager->nSubRec; ii++){
      assert( offset==(i64)ii*(4+pPager->pageSize) );
      rc = pager_playback_one_page(pPager, &offset, pDone, 0, 1);
    }
    assert( rc!=SQLITE_DONE );
  }

  sqlite3BitvecDestroy(pDone);
  if( rc==SQLITE_OK ){
    pPager->journalOff = szJ;
  }

  return rc;
}

/*
** Change the maximum number of in-memory pages that are allowed.
*/
SQLITE_PRIVATE void sqlite3PagerSetCachesize(Pager *pPager, int mxPage){
  sqlite3PcacheSetCachesize(pPager->pPCache, mxPage);
}

/*
** Free as much memory as possible from the pager.
*/
SQLITE_PRIVATE void sqlite3PagerShrink(Pager *pPager){
  sqlite3PcacheShrink(pPager->pPCache);
}

/*
** Adjust the robustness of the database to damage due to OS crashes
** or power failures by changing the number of syncs()s when writing
** the rollback journal.  There are three levels:
**
**    OFF       sqlite3OsSync() is never called.  This is the default

  }else if( bCkptFullFsync ){
    pPager->syncFlags = SQLITE_SYNC_NORMAL;
    pPager->ckptSyncFlags = SQLITE_SYNC_FULL;
  }else{
    pPager->syncFlags = SQLITE_SYNC_NORMAL;
    pPager->ckptSyncFlags = SQLITE_SYNC_NORMAL;
  }
  pPager->walSyncFlags = pPager->syncFlags;
  if( pPager->fullSync ){
    pPager->walSyncFlags |= WAL_SYNC_TRANSACTIONS;
  }
}
#endif

/*
** The following global variable is incremented whenever the library
** attempts to open a temporary file.  This information is used for
** testing and analysis only.  

    );
    rc = openSubJournal(pPager);

    /* If the sub-journal was opened successfully (or was already open),
    ** write the journal record into the file.  */
    if( rc==SQLITE_OK ){
      void *pData = pPg->pData;
      i64 offset = (i64)pPager->nSubRec*(4+pPager->pageSize);
      char *pData2;
  
      CODEC2(pPager, pData, pPg->pgno, 7, return SQLITE_NOMEM, pData2);
      PAGERTRACE(("STMT-JOURNAL %d page %d\n", PAGERID(pPager), pPg->pgno));
      rc = write32bits(pPager->sjfd, offset, pPg->pgno);
      if( rc==SQLITE_OK ){
        rc = sqlite3OsWrite(pPager->sjfd, pData2, pPager->pageSize, offset+4);

  pPg->pDirty = 0;
  if( pagerUseWal(pPager) ){
    /* Write a single frame for this page to the log. */
    if( subjRequiresPage(pPg) ){ 
      rc = subjournalPage(pPg); 
    }
    if( rc==SQLITE_OK ){
      rc = pagerWalFrames(pPager, pPg, 0, 0);
    }
  }else{
  
    /* Sync the journal file if required. */
    if( pPg->flags&PGHDR_NEED_SYNC 
     || pPager->eState==PAGER_WRITER_CACHEMOD
    ){

  assert( PAGER_LOCKINGMODE_EXCLUSIVE==1 );
  pPager->exclusiveMode = (u8)tempFile; 
  pPager->changeCountDone = pPager->tempFile;
  pPager->memDb = (u8)memDb;
  pPager->readOnly = (u8)readOnly;
  assert( useJournal || pPager->tempFile );
  pPager->noSync = pPager->tempFile;
  if( pPager->noSync ){
    assert( pPager->fullSync==0 );
    assert( pPager->syncFlags==0 );
    assert( pPager->walSyncFlags==0 );
    assert( pPager->ckptSyncFlags==0 );
  }else{
    pPager->fullSync = 1;
    pPager->syncFlags = SQLITE_SYNC_NORMAL;
    pPager->walSyncFlags = SQLITE_SYNC_NORMAL | WAL_SYNC_TRANSACTIONS;
    pPager->ckptSyncFlags = SQLITE_SYNC_NORMAL;
  }
  /* pPager->pFirst = 0; */
  /* pPager->pFirstSynced = 0; */
  /* pPager->pLast = 0; */
  pPager->nExtra = (u16)nExtra;
  pPager->journalSizeLimit = SQLITE_DEFAULT_JOURNAL_SIZE_LIMIT;
  assert( isOpen(pPager->fd) || tempFile );
  setSectorSize(pPager);

        ** Ticket [2d1a5c67dfc2363e44f29d9bbd57f] 2011-05-18 */
        rc = sqlite3PagerGet(pPager, 1, &pPageOne);
        pList = pPageOne;
        pList->pDirty = 0;
      }
      assert( rc==SQLITE_OK );
      if( ALWAYS(pList) ){
        rc = pagerWalFrames(pPager, pList, pPager->dbSize, 1);


      }
      sqlite3PagerUnref(pPageOne);
      if( rc==SQLITE_OK ){
        sqlite3PcacheCleanAll(pPager->pPCache);
      }
    }else{
      /* The following block updates the change-counter. Exactly how it

** in backup.c maintains the content of this variable. This module
** uses it opaquely as an argument to sqlite3BackupRestart() and
** sqlite3BackupUpdate() only.
*/
SQLITE_PRIVATE sqlite3_backup **sqlite3PagerBackupPtr(Pager *pPager){
  return &pPager->pBackup;
}

#ifndef SQLITE_OMIT_VACUUM
/*
** Unless this is an in-memory or temporary database, clear the pager cache.
*/
SQLITE_PRIVATE void sqlite3PagerClearCache(Pager *pPager){
  if( !MEMDB && pPager->tempFile==0 ) pager_reset(pPager);
}
#endif

#ifndef SQLITE_OMIT_WAL
/*
** This function is called when the user invokes "PRAGMA wal_checkpoint",
** "PRAGMA wal_blocking_checkpoint" or calls the sqlite3_wal_checkpoint()
** or wal_blocking_checkpoint() API functions.
**

                           pPager->pageSize, (u8*)pPager->pTmpSpace);
      pPager->pWal = 0;
    }
  }
  return rc;
}








#ifdef SQLITE_HAS_CODEC
/*
** This function is called by the wal module when writing page content
** into the log file.
**
** This function returns a pointer to a buffer containing the encrypted
** page content. If a malloc fails, this function may return NULL.

struct Wal {
  sqlite3_vfs *pVfs;         /* The VFS used to create pDbFd */
  sqlite3_file *pDbFd;       /* File handle for the database file */
  sqlite3_file *pWalFd;      /* File handle for WAL file */
  u32 iCallback;             /* Value to pass to log callback (or 0) */
  i64 mxWalSize;             /* Truncate WAL to this size upon reset */
  int nWiData;               /* Size of array apWiData */
  int szFirstBlock;          /* Size of first block written to WAL file */
  volatile u32 **apWiData;   /* Pointer to wal-index content in memory */
  u32 szPage;                /* Database page size */
  i16 readLock;              /* Which read lock is being held.  -1 for none */
  u8 syncFlags;              /* Flags to use to sync header writes */
  u8 exclusiveMode;          /* Non-zero if connection is in exclusive mode */
  u8 writeLock;              /* True if in a write transaction */
  u8 ckptLock;               /* True if holding a checkpoint lock */
  u8 readOnly;               /* WAL_RDWR, WAL_RDONLY, or WAL_SHM_RDONLY */
  u8 truncateOnCommit;       /* True to truncate WAL file on commit */
  u8 syncHeader;             /* Fsync the WAL header if true */
  u8 padToSectorBoundary;    /* Pad transactions out to the next sector */
  WalIndexHdr hdr;           /* Wal-index header for current transaction */
  const char *zWalName;      /* Name of WAL file */
  u32 nCkpt;                 /* Checkpoint sequence counter in the wal-header */
#ifdef SQLITE_DEBUG
  u8 lockError;              /* True if a locking error has occurred */
#endif
};

    int szFrame;                  /* Number of bytes in buffer aFrame[] */
    u8 *aData;                    /* Pointer to data part of aFrame buffer */
    int iFrame;                   /* Index of last frame read */
    i64 iOffset;                  /* Next offset to read from log file */
    int szPage;                   /* Page size according to the log */
    u32 magic;                    /* Magic value read from WAL header */
    u32 version;                  /* Magic value read from WAL header */
    int isValid;                  /* True if this frame is valid */

    /* Read in the WAL header. */
    rc = sqlite3OsRead(pWal->pWalFd, aBuf, WAL_HDRSIZE, 0);
    if( rc!=SQLITE_OK ){
      goto recovery_error;
    }

    aData = &aFrame[WAL_FRAME_HDRSIZE];

    /* Read all frames from the log file. */
    iFrame = 0;
    for(iOffset=WAL_HDRSIZE; (iOffset+szFrame)<=nSize; iOffset+=szFrame){
      u32 pgno;                   /* Database page number for frame */
      u32 nTruncate;              /* dbsize field from frame header */


      /* Read and decode the next log frame. */
      iFrame++;
      rc = sqlite3OsRead(pWal->pWalFd, aFrame, szFrame, iOffset);
      if( rc!=SQLITE_OK ) break;
      isValid = walDecodeFrame(pWal, &pgno, &nTruncate, aData, aFrame);
      if( !isValid ) break;
      rc = walIndexAppend(pWal, iFrame, pgno);
      if( rc!=SQLITE_OK ) break;

      /* If nTruncate is non-zero, this is a commit record. */
      if( nTruncate ){
        pWal->hdr.mxFrame = iFrame;
        pWal->hdr.nPage = nTruncate;
        pWal->hdr.szPage = (u16)((szPage&0xff00) | (szPage>>16));

  pRet->pVfs = pVfs;
  pRet->pWalFd = (sqlite3_file *)&pRet[1];
  pRet->pDbFd = pDbFd;
  pRet->readLock = -1;
  pRet->mxWalSize = mxWalSize;
  pRet->zWalName = zWalName;
  pRet->syncHeader = 1;
  pRet->padToSectorBoundary = 1;
  pRet->exclusiveMode = (bNoShm ? WAL_HEAPMEMORY_MODE: WAL_NORMAL_MODE);

  /* Open file handle on the write-ahead log file. */
  flags = (SQLITE_OPEN_READWRITE|SQLITE_OPEN_CREATE|SQLITE_OPEN_WAL);
  rc = sqlite3OsOpen(pVfs, zWalName, pRet->pWalFd, flags, &flags);
  if( rc==SQLITE_OK && flags&SQLITE_OPEN_READONLY ){
    pRet->readOnly = WAL_RDONLY;
  }

  if( rc!=SQLITE_OK ){
    walIndexClose(pRet, 0);
    sqlite3OsClose(pRet->pWalFd);
    sqlite3_free(pRet);
  }else{
    int iDC = sqlite3OsDeviceCharacteristics(pRet->pWalFd);
    if( iDC & SQLITE_IOCAP_SEQUENTIAL ){ pRet->syncHeader = 0; }
    if( iDC & SQLITE_IOCAP_POWERSAFE_OVERWRITE ){
      pRet->padToSectorBoundary = 0;
    }
    *ppWal = pRet;
    WALTRACE(("WAL%d: opened\n", pRet));
  }
  return rc;
}

/*

    }
  }

 walcheckpoint_out:
  walIteratorFree(pIter);
  return rc;
}

/*
** If the WAL file is currently larger than nMax bytes in size, truncate
** it to exactly nMax bytes. If an error occurs while doing so, ignore it.
*/
static void walLimitSize(Wal *pWal, i64 nMax){
  i64 sz;
  int rx;
  sqlite3BeginBenignMalloc();
  rx = sqlite3OsFileSize(pWal->pWalFd, &sz);
  if( rx==SQLITE_OK && (sz > nMax ) ){
    rx = sqlite3OsTruncate(pWal->pWalFd, nMax);
  }
  sqlite3EndBenignMalloc();
  if( rx ){
    sqlite3_log(rx, "cannot limit WAL size: %s", pWal->zWalName);
  }
}

/*
** Close a connection to a log file.
*/
SQLITE_PRIVATE int sqlite3WalClose(
  Wal *pWal,                      /* Wal to close */
  int sync_flags,                 /* Flags to pass to OsSync() (or 0) */

    ** the database. In this case checkpoint the database and unlink both
    ** the wal and wal-index files.
    **
    ** The EXCLUSIVE lock is not released before returning.
    */
    rc = sqlite3OsLock(pWal->pDbFd, SQLITE_LOCK_EXCLUSIVE);
    if( rc==SQLITE_OK ){

      if( pWal->exclusiveMode==WAL_NORMAL_MODE ){
        pWal->exclusiveMode = WAL_EXCLUSIVE_MODE;
      }
      rc = sqlite3WalCheckpoint(
          pWal, SQLITE_CHECKPOINT_PASSIVE, 0, 0, sync_flags, nBuf, zBuf, 0, 0
      );
      if( rc==SQLITE_OK ){
        int bPersist = -1;
        sqlite3OsFileControl(pWal->pDbFd, SQLITE_FCNTL_PERSIST_WAL, &bPersist);
        if( bPersist!=1 ){
          /* Try to delete the WAL file if the checkpoint completed and
          ** fsyned (rc==SQLITE_OK) and if we are not in persistent-wal
          ** mode (!bPersist) */
          isDelete = 1;
        }else if( pWal->mxWalSize>=0 ){
          /* Try to truncate the WAL file to zero bytes if the checkpoint
          ** completed and fsynced (rc==SQLITE_OK) and we are in persistent
          ** WAL mode (bPersist) and if the PRAGMA journal_size_limit is a
          ** non-negative value (pWal->mxWalSize>=0).  Note that we truncate
          ** to zero bytes as truncating to the journal_size_limit might
          ** leave a corrupt WAL file on disk. */
          walLimitSize(pWal, 0);
        }
      }
    }

    walIndexClose(pWal, isDelete);
    sqlite3OsClose(pWal->pWalFd);
    if( isDelete ){
      sqlite3OsDelete(pWal->pVfs, pWal->zWalName, 0);

    if( rc!=SQLITE_OK ){
      return rc;
    }
    nCollide = HASHTABLE_NSLOT;
    for(iKey=walHash(pgno); aHash[iKey]; iKey=walNextHash(iKey)){
      u32 iFrame = aHash[iKey] + iZero;
      if( iFrame<=iLast && aPgno[aHash[iKey]]==pgno ){
        /* assert( iFrame>iRead ); -- not true if there is corruption */
        iRead = iFrame;
      }
      if( (nCollide--)==0 ){
        return SQLITE_CORRUPT_BKPT;
      }
    }
  }

** End a write transaction.  The commit has already been done.  This
** routine merely releases the lock.
*/
SQLITE_PRIVATE int sqlite3WalEndWriteTransaction(Wal *pWal){
  if( pWal->writeLock ){
    walUnlockExclusive(pWal, WAL_WRITE_LOCK, 1);
    pWal->writeLock = 0;
    pWal->truncateOnCommit = 0;
  }
  return SQLITE_OK;
}

/*
** If any data has been written (but not committed) to the log file, this
** function moves the write-pointer back to the start of the transaction.

    pWal->hdr.aFrameCksum[0] = aWalData[1];
    pWal->hdr.aFrameCksum[1] = aWalData[2];
    walCleanupHash(pWal);
  }

  return rc;
}


/*
** This function is called just before writing a set of frames to the log
** file (see sqlite3WalFrames()). It checks to see if, instead of appending
** to the current log file, it is possible to overwrite the start of the
** existing log file with the new frames (i.e. "reset" the log). If so,
** it sets pWal->hdr.mxFrame to 0. Otherwise, pWal->hdr.mxFrame is left

        ** at this point. But updating the actual wal-index header is also
        ** safe and means there is no special case for sqlite3WalUndo()
        ** to handle if this transaction is rolled back.
        */
        int i;                    /* Loop counter */
        u32 *aSalt = pWal->hdr.aSalt;       /* Big-endian salt values */


















        pWal->nCkpt++;
        pWal->hdr.mxFrame = 0;
        sqlite3Put4byte((u8*)&aSalt[0], 1 + sqlite3Get4byte((u8*)&aSalt[0]));
        aSalt[1] = salt1;
        walIndexWriteHdr(pWal);
        pInfo->nBackfill = 0;
        for(i=1; i<WAL_NREADER; i++) pInfo->aReadMark[i] = READMARK_NOT_USED;

    assert( (rc&0xff)!=SQLITE_BUSY ); /* BUSY not possible when useWal==1 */
    testcase( (rc&0xff)==SQLITE_IOERR );
    testcase( rc==SQLITE_PROTOCOL );
    testcase( rc==SQLITE_OK );
  }
  return rc;
}

/*
** Information about the current state of the WAL file and where
** the next fsync should occur - passed from sqlite3WalFrames() into
** walWriteToLog().
*/
typedef struct WalWriter {
  Wal *pWal;                   /* The complete WAL information */
  sqlite3_file *pFd;           /* The WAL file to which we write */
  sqlite3_int64 iSyncPoint;    /* Fsync at this offset */
  int syncFlags;               /* Flags for the fsync */
  int szPage;                  /* Size of one page */
} WalWriter;

/*
** Write iAmt bytes of content into the WAL file beginning at iOffset.
** Do a sync when crossing the p->iSyncPoint boundary.
**
** In other words, if iSyncPoint is in between iOffset and iOffset+iAmt,
** first write the part before iSyncPoint, then sync, then write the
** rest.
*/
static int walWriteToLog(
  WalWriter *p,              /* WAL to write to */
  void *pContent,            /* Content to be written */
  int iAmt,                  /* Number of bytes to write */
  sqlite3_int64 iOffset      /* Start writing at this offset */
){
  int rc;
  if( iOffset<p->iSyncPoint && iOffset+iAmt>=p->iSyncPoint ){
    int iFirstAmt = (int)(p->iSyncPoint - iOffset);
    rc = sqlite3OsWrite(p->pFd, pContent, iFirstAmt, iOffset);
    if( rc ) return rc;
    iOffset += iFirstAmt;
    iAmt -= iFirstAmt;
    pContent = (void*)(iFirstAmt + (char*)pContent);
    assert( p->syncFlags & (SQLITE_SYNC_NORMAL|SQLITE_SYNC_FULL) );
    rc = sqlite3OsSync(p->pFd, p->syncFlags);
    if( iAmt==0 || rc ) return rc;
  }
  rc = sqlite3OsWrite(p->pFd, pContent, iAmt, iOffset);
  return rc;
}

/*
** Write out a single frame of the WAL
*/
static int walWriteOneFrame(
  WalWriter *p,               /* Where to write the frame */
  PgHdr *pPage,               /* The page of the frame to be written */
  int nTruncate,              /* The commit flag.  Usually 0.  >0 for commit */
  sqlite3_int64 iOffset       /* Byte offset at which to write */
){
  int rc;                         /* Result code from subfunctions */
  void *pData;                    /* Data actually written */
  u8 aFrame[WAL_FRAME_HDRSIZE];   /* Buffer to assemble frame-header in */
#if defined(SQLITE_HAS_CODEC)
  if( (pData = sqlite3PagerCodec(pPage))==0 ) return SQLITE_NOMEM;
#else
  pData = pPage->pData;
#endif
  walEncodeFrame(p->pWal, pPage->pgno, nTruncate, pData, aFrame);
  rc = walWriteToLog(p, aFrame, sizeof(aFrame), iOffset);
  if( rc ) return rc;
  /* Write the page data */
  rc = walWriteToLog(p, pData, p->szPage, iOffset+sizeof(aFrame));
  return rc;
}

/* 
** Write a set of frames to the log. The caller must hold the write-lock
** on the log file (obtained using sqlite3WalBeginWriteTransaction()).
*/
SQLITE_PRIVATE int sqlite3WalFrames(
  Wal *pWal,                      /* Wal handle to write to */
  int szPage,                     /* Database page-size in bytes */
  PgHdr *pList,                   /* List of dirty pages to write */
  Pgno nTruncate,                 /* Database size after this commit */
  int isCommit,                   /* True if this is a commit */
  int sync_flags                  /* Flags to pass to OsSync() (or 0) */
){
  int rc;                         /* Used to catch return codes */
  u32 iFrame;                     /* Next frame address */

  PgHdr *p;                       /* Iterator to run through pList with. */
  PgHdr *pLast = 0;               /* Last frame in list */
  int nExtra = 0;                 /* Number of extra copies of last page */
  int szFrame;                    /* The size of a single frame */
  i64 iOffset;                    /* Next byte to write in WAL file */
  WalWriter w;                    /* The writer */

  assert( pList );
  assert( pWal->writeLock );

  /* If this frame set completes a transaction, then nTruncate>0.  If
  ** nTruncate==0 then this frame set does not complete the transaction. */
  assert( (isCommit!=0)==(nTruncate!=0) );

#if defined(SQLITE_TEST) && defined(SQLITE_DEBUG)
  { int cnt; for(cnt=0, p=pList; p; p=p->pDirty, cnt++){}
    WALTRACE(("WAL%p: frame write begin. %d frames. mxFrame=%d. %s\n",
              pWal, cnt, pWal->hdr.mxFrame, isCommit ? "Commit" : "Spill"));
  }
#endif

    u8 aWalHdr[WAL_HDRSIZE];      /* Buffer to assemble wal-header in */
    u32 aCksum[2];                /* Checksum for wal-header */

    sqlite3Put4byte(&aWalHdr[0], (WAL_MAGIC | SQLITE_BIGENDIAN));
    sqlite3Put4byte(&aWalHdr[4], WAL_MAX_VERSION);
    sqlite3Put4byte(&aWalHdr[8], szPage);
    sqlite3Put4byte(&aWalHdr[12], pWal->nCkpt);
    if( pWal->nCkpt==0 ) sqlite3_randomness(8, pWal->hdr.aSalt);
    memcpy(&aWalHdr[16], pWal->hdr.aSalt, 8);
    walChecksumBytes(1, aWalHdr, WAL_HDRSIZE-2*4, 0, aCksum);
    sqlite3Put4byte(&aWalHdr[24], aCksum[0]);
    sqlite3Put4byte(&aWalHdr[28], aCksum[1]);
    
    pWal->szPage = szPage;
    pWal->hdr.bigEndCksum = SQLITE_BIGENDIAN;
    pWal->hdr.aFrameCksum[0] = aCksum[0];
    pWal->hdr.aFrameCksum[1] = aCksum[1];
    pWal->truncateOnCommit = 1;

    rc = sqlite3OsWrite(pWal->pWalFd, aWalHdr, sizeof(aWalHdr), 0);
    WALTRACE(("WAL%p: wal-header write %s\n", pWal, rc ? "failed" : "ok"));
    if( rc!=SQLITE_OK ){
      return rc;
    }

    /* Sync the header (unless SQLITE_IOCAP_SEQUENTIAL is true or unless
    ** all syncing is turned off by PRAGMA synchronous=OFF).  Otherwise
    ** an out-of-order write following a WAL restart could result in
    ** database corruption.  See the ticket:
    **
    **     http://localhost:591/sqlite/info/ff5be73dee
    */
    if( pWal->syncHeader && sync_flags ){
      rc = sqlite3OsSync(pWal->pWalFd, sync_flags & SQLITE_SYNC_MASK);
      if( rc ) return rc;
    }
  }
  assert( (int)pWal->szPage==szPage );

  /* Setup information needed to write frames into the WAL */
  w.pWal = pWal;
  w.pFd = pWal->pWalFd;

  w.iSyncPoint = 0;
  w.syncFlags = sync_flags;
  w.szPage = szPage;
  iOffset = walFrameOffset(iFrame+1, szPage);
  szFrame = szPage + WAL_FRAME_HDRSIZE;

  /* Write all frames into the log file exactly once */
  for(p=pList; p; p=p->pDirty){
    int nDbSize;   /* 0 normally.  Positive == commit flag */
    iFrame++;
    assert( iOffset==walFrameOffset(iFrame, szPage) );
    nDbSize = (isCommit && p->pDirty==0) ? nTruncate : 0;










    rc = walWriteOneFrame(&w, p, nDbSize, iOffset);



    if( rc ) return rc;

    pLast = p;
    iOffset += szFrame;
  }

  /* If this is the end of a transaction, then we might need to pad
  ** the transaction and/or sync the WAL file.
  **
  ** Padding and syncing only occur if this set of frames complete a
  ** transaction and if PRAGMA synchronous=FULL.  If synchronous==NORMAL
  ** or synchonous==OFF, then no padding or syncing are needed.
  **
  ** If SQLITE_IOCAP_POWERSAFE_OVERWRITE is defined, then padding is not
  ** needed and only the sync is done.  If padding is needed, then the
  ** final frame is repeated (with its commit mark) until the next sector
  ** boundary is crossed.  Only the part of the WAL prior to the last
  ** sector boundary is synced; the part of the last frame that extends
  ** past the sector boundary is written after the sync.
  */
  if( isCommit && (sync_flags & WAL_SYNC_TRANSACTIONS)!=0 ){
    if( pWal->padToSectorBoundary ){
      int sectorSize = sqlite3OsSectorSize(pWal->pWalFd);

      w.iSyncPoint = ((iOffset+sectorSize-1)/sectorSize)*sectorSize;




      while( iOffset<w.iSyncPoint ){
        rc = walWriteOneFrame(&w, pLast, nTruncate, iOffset);

        if( rc ) return rc;
        iOffset += szFrame;
        nExtra++;
      }
    }else{




      rc = sqlite3OsSync(w.pFd, sync_flags & SQLITE_SYNC_MASK);


    }




  }



  /* If this frame set completes the first transaction in the WAL and
  ** if PRAGMA journal_size_limit is set, then truncate the WAL to the
  ** journal size limit, if possible.
  */
  if( isCommit && pWal->truncateOnCommit && pWal->mxWalSize>=0 ){
    i64 sz = pWal->mxWalSize;
    if( walFrameOffset(iFrame+nExtra+1, szPage)>pWal->mxWalSize ){
      sz = walFrameOffset(iFrame+nExtra+1, szPage);
    }
    walLimitSize(pWal, sz);
    pWal->truncateOnCommit = 0;
  }

  /* Append data to the wal-index. It is not necessary to lock the 
  ** wal-index to do this as the SQLITE_SHM_WRITE lock held on the wal-index
  ** guarantees that there are no other writers, and no data that may
  ** be in use by existing readers is being overwritten.
  */
  iFrame = pWal->hdr.mxFrame;
  for(p=pList; p && rc==SQLITE_OK; p=p->pDirty){
    iFrame++;
    rc = walIndexAppend(pWal, iFrame, p->pgno);
  }
  while( nExtra>0 && rc==SQLITE_OK ){
    iFrame++;
    nExtra--;
    rc = walIndexAppend(pWal, iFrame, pLast->pgno);
  }

  if( rc==SQLITE_OK ){
    /* Update the private copy of the header. */
    pWal->hdr.szPage = (u16)((szPage&0xff00) | (szPage>>16));
    testcase( szPage<=32768 );

  u16 maskPage;        /* Mask for page offset */
  struct _OvflCell {   /* Cells that will not fit on aData[] */
    u8 *pCell;          /* Pointers to the body of the overflow cell */
    u16 idx;            /* Insert this cell before idx-th non-overflow cell */
  } aOvfl[5];
  BtShared *pBt;       /* Pointer to BtShared that this page is part of */
  u8 *aData;           /* Pointer to disk image of the page data */
  u8 *aDataEnd;        /* One byte past the end of usable data */
  u8 *aCellIdx;        /* The cell index area */
  DbPage *pDbPage;     /* Pager page handle */
  Pgno pgno;           /* Page number for this page */
};

/*
** The in-memory image of a disk page has the auxiliary information appended
** to the end.  EXTRA_SIZE is the number of bytes of space needed to hold

** Given a btree page and a cell index (0 means the first cell on
** the page, 1 means the second cell, and so forth) return a pointer
** to the cell content.
**
** This routine works only for pages that do not contain overflow cells.
*/
#define findCell(P,I) \
  ((P)->aData + ((P)->maskPage & get2byte(&(P)->aCellIdx[2*(I)])))
#define findCellv2(D,M,O,I) (D+(M&get2byte(D+(O+2*(I)))))


/*
** This a more complex version of findCell() that works for
** pages that do contain overflow cells.
*/

    data = pPage->aData;
    if( decodeFlags(pPage, data[hdr]) ) return SQLITE_CORRUPT_BKPT;
    assert( pBt->pageSize>=512 && pBt->pageSize<=65536 );
    pPage->maskPage = (u16)(pBt->pageSize - 1);
    pPage->nOverflow = 0;
    usableSize = pBt->usableSize;
    pPage->cellOffset = cellOffset = hdr + 12 - 4*pPage->leaf;
    pPage->aDataEnd = &data[usableSize];
    pPage->aCellIdx = &data[cellOffset];
    top = get2byteNotZero(&data[hdr+5]);
    pPage->nCell = get2byte(&data[hdr+3]);
    if( pPage->nCell>MX_CELL(pBt) ){
      /* To many cells for a single page.  The page must be corrupt */
      return SQLITE_CORRUPT_BKPT;
    }
    testcase( pPage->nCell==MX_CELL(pBt) );

  memset(&data[hdr+1], 0, 4);
  data[hdr+7] = 0;
  put2byte(&data[hdr+5], pBt->usableSize);
  pPage->nFree = (u16)(pBt->usableSize - first);
  decodeFlags(pPage, flags);
  pPage->hdrOffset = hdr;
  pPage->cellOffset = first;
  pPage->aDataEnd = &data[pBt->usableSize];
  pPage->aCellIdx = &data[first];
  pPage->nOverflow = 0;
  assert( pBt->pageSize>=512 && pBt->pageSize<=65536 );
  pPage->maskPage = (u16)(pBt->pageSize - 1);
  pPage->nCell = 0;
  pPage->isInit = 1;
}

      char *zFullPathname = sqlite3Malloc(nFullPathname);
      MUTEX_LOGIC( sqlite3_mutex *mutexShared; )
      p->sharable = 1;
      if( !zFullPathname ){
        sqlite3_free(p);
        return SQLITE_NOMEM;
      }
      rc = sqlite3OsFullPathname(pVfs, zFilename, nFullPathname, zFullPathname);
      if( rc ){
        sqlite3_free(zFullPathname);
        sqlite3_free(p);
        return rc;
      }
#if SQLITE_THREADSAFE
      mutexOpen = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_OPEN);
      sqlite3_mutex_enter(mutexOpen);
      mutexShared = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER);
      sqlite3_mutex_enter(mutexShared);
#endif
      for(pBt=GLOBAL(BtShared*,sqlite3SharedCacheList); pBt; pBt=pBt->pNext){

         && pBt->inTransaction==TRANS_READ                     /* (4) */
         && (fd = sqlite3PagerFile(pBt->pPager))->pMethods     /* (3) */
         && pBt->pPage1->aData[19]==0x01                       /* (5) */
        ){
          u8 aSave[4];
          u8 *aWrite = &pBuf[-4];
          memcpy(aSave, aWrite, 4);
          rc = sqlite3OsRead(fd, aWrite, a+4, (i64)pBt->pageSize*(nextPage-1));
          nextPage = get4byte(aWrite);
          memcpy(aWrite, aSave, 4);
        }else
#endif

        {
          DbPage *pDbPage;

        ** page is less than 16384 bytes and may be stored as a 2-byte
        ** varint. This information is used to attempt to avoid parsing 
        ** the entire cell by checking for the cases where the record is 
        ** stored entirely within the b-tree page by inspecting the first 
        ** 2 bytes of the cell.
        */
        int nCell = pCell[0];
        if( !(nCell & 0x80)
         && nCell<=pPage->maxLocal
         && (pCell+nCell+1)<=pPage->aDataEnd
        ){
          /* This branch runs if the record-size field of the cell is a
          ** single byte varint and the record fits entirely on the main
          ** b-tree page.  */
          testcase( pCell+nCell+1==pPage->aDataEnd );
          c = sqlite3VdbeRecordCompare(nCell, (void*)&pCell[1], pIdxKey);
        }else if( !(pCell[1] & 0x80) 
          && (nCell = ((nCell&0x7f)<<7) + pCell[1])<=pPage->maxLocal
          && (pCell+nCell+2)<=pPage->aDataEnd
        ){
          /* The record-size field is a 2 byte varint and the record 
          ** fits entirely on the main b-tree page.  */
          testcase( pCell+nCell+2==pPage->aDataEnd );
          c = sqlite3VdbeRecordCompare(nCell, (void*)&pCell[2], pIdxKey);
        }else{
          /* The record flows over onto one or more overflow pages. In
          ** this case the whole cell needs to be parsed, a buffer allocated
          ** and accessPayload() used to retrieve the record into the
          ** buffer before VdbeRecordCompare() can be called. */
          void *pCellKey;

  if( *pRC ) return;

  assert( idx>=0 && idx<pPage->nCell );
  assert( sz==cellSize(pPage, idx) );
  assert( sqlite3PagerIswriteable(pPage->pDbPage) );
  assert( sqlite3_mutex_held(pPage->pBt->mutex) );
  data = pPage->aData;
  ptr = &pPage->aCellIdx[2*idx];
  pc = get2byte(ptr);
  hdr = pPage->hdrOffset;
  testcase( pc==get2byte(&data[hdr+5]) );
  testcase( pc+sz==pPage->pBt->usableSize );
  if( pc < (u32)get2byte(&data[hdr+5]) || pc+sz > pPage->pBt->usableSize ){
    *pRC = SQLITE_CORRUPT_BKPT;
    return;
  }
  rc = freeSpace(pPage, pc, sz);
  if( rc ){
    *pRC = rc;
    return;
  }
  endPtr = &pPage->aCellIdx[2*pPage->nCell - 2];
  assert( (SQLITE_PTR_TO_INT(ptr)&1)==0 );  /* ptr is always 2-byte aligned */
  while( ptr<endPtr ){
    *(u16*)ptr = *(u16*)&ptr[2];
    ptr += 2;
  }
  pPage->nCell--;
  put2byte(&data[hdr+3], pPage->nCell);

            && (int)MX_CELL(pPage->pBt)<=10921);
  assert( sqlite3PagerIswriteable(pPage->pDbPage) );

  /* Check that the page has just been zeroed by zeroPage() */
  assert( pPage->nCell==0 );
  assert( get2byteNotZero(&data[hdr+5])==nUsable );

  pCellptr = &pPage->aCellIdx[nCell*2];
  cellbody = nUsable;
  for(i=nCell-1; i>=0; i--){
    u16 sz = aSize[i];
    pCellptr -= 2;
    cellbody -= sz;
    put2byte(pCellptr, cellbody);
    memcpy(&data[cellbody], apCell[i], sz);

    }
    case P4_REAL: {
      sqlite3_snprintf(nTemp, zTemp, "%.16g", *pOp->p4.pReal);
      break;
    }
    case P4_MEM: {
      Mem *pMem = pOp->p4.pMem;

      if( pMem->flags & MEM_Str ){
        zP4 = pMem->z;
      }else if( pMem->flags & MEM_Int ){
        sqlite3_snprintf(nTemp, zTemp, "%lld", pMem->u.i);
      }else if( pMem->flags & MEM_Real ){
        sqlite3_snprintf(nTemp, zTemp, "%.16g", pMem->r);
      }else if( pMem->flags & MEM_Null ){
        sqlite3_snprintf(nTemp, zTemp, "NULL");
      }else{
        assert( pMem->flags & MEM_Blob );
        zP4 = "(blob)";
      }
      break;
    }
#ifndef SQLITE_OMIT_VIRTUALTABLE

      if( p->flags&(MEM_Agg|MEM_Dyn|MEM_Frame|MEM_RowSet) ){
        sqlite3VdbeMemRelease(p);
      }else if( p->zMalloc ){
        sqlite3DbFree(db, p->zMalloc);
        p->zMalloc = 0;
      }

      p->flags = MEM_Invalid;
    }
    db->mallocFailed = malloc_failed;
  }
}

/*
** Delete a VdbeFrame object and its contents. VdbeFrame objects are

  Parse *pParse                  /* Parsing context */
){
  sqlite3 *db;                   /* The database connection */
  int nVar;                      /* Number of parameters */
  int nMem;                      /* Number of VM memory registers */
  int nCursor;                   /* Number of cursors required */
  int nArg;                      /* Number of arguments in subprograms */
  int nOnce;                     /* Number of OP_Once instructions */
  int n;                         /* Loop counter */
  u8 *zCsr;                      /* Memory available for allocation */
  u8 *zEnd;                      /* First byte past allocated memory */
  int nByte;                     /* How much extra memory is needed */

  assert( p!=0 );
  assert( p->nOp>0 );
  assert( pParse!=0 );
  assert( p->magic==VDBE_MAGIC_INIT );
  db = p->db;
  assert( db->mallocFailed==0 );
  nVar = pParse->nVar;
  nMem = pParse->nMem;
  nCursor = pParse->nTab;
  nArg = pParse->nMaxArg;
  nOnce = pParse->nOnce;
  
  /* For each cursor required, also allocate a memory cell. Memory
  ** cells (nMem+1-nCursor)..nMem, inclusive, will never be used by
  ** the vdbe program. Instead they are used to allocate space for
  ** VdbeCursor/BtCursor structures. The blob of memory associated with 
  ** cursor 0 is stored in memory cell nMem. Memory cell (nMem-1)
  ** stores the blob of memory associated with cursor 1, etc.

    nByte = 0;
    p->aMem = allocSpace(p->aMem, nMem*sizeof(Mem), &zCsr, zEnd, &nByte);
    p->aVar = allocSpace(p->aVar, nVar*sizeof(Mem), &zCsr, zEnd, &nByte);
    p->apArg = allocSpace(p->apArg, nArg*sizeof(Mem*), &zCsr, zEnd, &nByte);
    p->azVar = allocSpace(p->azVar, nVar*sizeof(char*), &zCsr, zEnd, &nByte);
    p->apCsr = allocSpace(p->apCsr, nCursor*sizeof(VdbeCursor*),
                          &zCsr, zEnd, &nByte);
    p->aOnceFlag = allocSpace(p->aOnceFlag, nOnce, &zCsr, zEnd, &nByte);
    if( nByte ){
      p->pFree = sqlite3DbMallocZero(db, nByte);
    }
    zCsr = p->pFree;
    zEnd = &zCsr[nByte];
  }while( nByte && !db->mallocFailed );

  p->nCursor = (u16)nCursor;
  p->nOnceFlag = nOnce;
  if( p->aVar ){
    p->nVar = (ynVar)nVar;
    for(n=0; n<nVar; n++){
      p->aVar[n].flags = MEM_Null;
      p->aVar[n].db = db;
    }
  }
  if( p->azVar ){
    p->nzVar = pParse->nzVar;
    memcpy(p->azVar, pParse->azVar, p->nzVar*sizeof(p->azVar[0]));
    memset(pParse->azVar, 0, pParse->nzVar*sizeof(pParse->azVar[0]));
  }
  if( p->aMem ){
    p->aMem--;                      /* aMem[] goes from 1..nMem */
    p->nMem = nMem;                 /*       not from 0..nMem-1 */
    for(n=1; n<=nMem; n++){
      p->aMem[n].flags = MEM_Invalid;
      p->aMem[n].db = db;
    }
  }
  p->explain = pParse->explain;
  sqlite3VdbeRewind(p);
}

/*
** Copy the values stored in the VdbeFrame structure to its Vdbe. This
** is used, for example, when a trigger sub-program is halted to restore
** control to the main program.
*/
SQLITE_PRIVATE int sqlite3VdbeFrameRestore(VdbeFrame *pFrame){
  Vdbe *v = pFrame->v;
  v->aOnceFlag = pFrame->aOnceFlag;
  v->nOnceFlag = pFrame->nOnceFlag;
  v->aOp = pFrame->aOp;
  v->nOp = pFrame->nOp;
  v->aMem = pFrame->aMem;
  v->nMem = pFrame->nMem;
  v->apCsr = pFrame->apCsr;
  v->nCursor = pFrame->nCursor;
  v->db->lastRowid = pFrame->lastRowid;

static void Cleanup(Vdbe *p){
  sqlite3 *db = p->db;

#ifdef SQLITE_DEBUG
  /* Execute assert() statements to ensure that the Vdbe.apCsr[] and 
  ** Vdbe.aMem[] arrays have already been cleaned up.  */
  int i;
  if( p->apCsr ) for(i=0; i<p->nCursor; i++) assert( p->apCsr[i]==0 );
  if( p->aMem ){
    for(i=1; i<=p->nMem; i++) assert( p->aMem[i].flags==MEM_Invalid );
  }
#endif

  sqlite3DbFree(db, p->zErrMsg);
  p->zErrMsg = 0;
  p->pResultSet = 0;
}