Fossil

All of the source code for fossil is contained in the src/ subdirectory.
But there is a lot of generated code, so you will probably want to
use the Makefile.  To do a complete build, just type:

   make

That should work out-of-the-box on Macs and Linux systems. If you are
building on a Windows box, install MinGW as well as MinGW's make (or
MSYS). You can then type:

   make -f Makefile.w32

If you have trouble, or you want to do something fancy, just look at
top level makefile. There are 6 configuration options that are all well
commented. Instead of editing the Makefile, consider copying the Makefile
to an alternative name such as "GNUMakefile", "BSDMakefile", or "makefile"
and editing the copy.

Out of source builds?
--------------------------------------------------------------------------

An out of source build is pretty easy:

  1. Make a new directory to do the builds in.
  2. Copy "Makefile" from the source into the build directory and
  modify the SRCDIR macro along the lines of:

    SRCDIR=../src


  3. type: "make"






This will now keep all generates files seperate from the maintained
source code.

--------------------------------------------------------------------------

Here are some notes on what is happening behind the scenes:

/*
** Copyright (c) 2007 D. Richard Hipp
**
** This program is free software; you can redistribute it and/or
** modify it under the terms of the GNU General Public
** License version 2 as published by the Free Software Foundation.
**
** This program is distributed in the hope that it will be useful,
** but WITHOUT ANY WARRANTY; without even the implied warranty of
** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
** General Public License for more details.
**
** You should have received a copy of the GNU General Public
** License along with this library; if not, write to the
** Free Software Foundation, Inc., 59 Temple Place - Suite 330,
** Boston, MA  02111-1307, USA.
**
** Author contact information:
**   drh@hwaci.com

#include <dirent.h>

/*
** Set to true if files whose names begin with "." should be
** included when processing a recursive "add" command.
*/
static int includeDotFiles = 0;

/*
** Add a single file
*/
static void add_one_file(const char *zName, int vid, Blob *pOmit){
  Blob pathname;
  const char *zPath;

  file_tree_name(zName, &pathname, 1);
  zPath = blob_str(&pathname);
  if( strcmp(zPath, "manifest")==0
   || strcmp(zPath, "_FOSSIL_")==0
   || strcmp(zPath, "manifest.uuid")==0
   || blob_compare(&pathname, pOmit)==0
  ){
    fossil_warning("cannot add %s", zPath);
  }else{
    if( !file_is_simple_pathname(zPath) ){
      fossil_fatal("filename contains illegal characters: %s", zPath);
    }
#ifdef __MINGW32__
    if( db_exists("SELECT 1 FROM vfile"
                  " WHERE pathname=%Q COLLATE nocase", zPath) ){
      db_multi_exec("UPDATE vfile SET deleted=0"
                    " WHERE pathname=%Q COLLATE nocase", zPath);
    }
#else
    if( db_exists("SELECT 1 FROM vfile WHERE pathname=%Q", zPath) ){
      db_multi_exec("UPDATE vfile SET deleted=0 WHERE pathname=%Q", zPath);
    }
#endif
    else{

}

/*
** COMMAND: add
**
** Usage: %fossil add FILE...
**
** Make arrangements to add one or more files to the current checkout
** at the next commit.
**
** When adding files recursively, filenames that begin with "." are
** excluded by default.  To include such files, add the "--dotfiles"
** option to the command-line.
*/
void add_cmd(void){

    free(zName);
  }
  db_multi_exec("DELETE FROM vfile WHERE deleted AND rid=0");
  db_end_transaction(0);
}

/*
** Rename a single file.
**
** The original name of the file is zOrig.  The new filename is zNew.
*/
static void mv_one_file(int vid, const char *zOrig, const char *zNew){
  printf("RENAME %s %s\n", zOrig, zNew);
  db_multi_exec(
    "UPDATE vfile SET pathname='%s' WHERE pathname='%s' AND vid=%d",

** ancestor identified rid and zUuid.  Throw a fatal error if not.
*/
static void checkin_verify_younger(
  int rid,              /* The record ID of the ancestor */
  const char *zUuid,    /* The artifact ID of the ancestor */
  const char *zDate     /* Date & time of the current check-in */
){
#ifndef FOSSIL_ALLOW_OUT_OF_ORDER_DATES
  int b;
  b = db_exists(
    "SELECT 1 FROM event"
    " WHERE datetime(mtime)>=%Q"
    "   AND type='ci' AND objid=%d",
    zDate, rid
  );
  if( b ){
    fossil_fatal("ancestor check-in [%.10s] (%s) is younger (clock skew?)",
                 zUuid, zDate);
  }
#endif
}

/*
** COMMAND: ci
** COMMAND: commit
**
** Usage: %fossil commit ?OPTIONS? ?FILE...?

/*
** Compute the complete graph
*/
void graph_finish(GraphContext *p, int omitDescenders){
  GraphRow *pRow, *pDesc;
  Bag allRids;
  Bag notLeaf;
  int i;
  int nRow;
  u32 mask;
  u32 inUse;

  if( p==0 || p->pFirst==0 || p->nErr ) return;

  /* Initialize all rows */
  bag_init(&allRids);
  bag_init(&notLeaf);
  nRow = 0;
  for(pRow=p->pFirst; pRow; pRow=pRow->pNext){
    if( pRow->pNext ) pRow->pNext->pPrev = pRow;
    pRow->idx = ++nRow;
    pRow->iRail = -1;
    pRow->mergeOut = -1;
    bag_insert(&allRids, pRow->rid);
  }
  p->mxRail = -1;

  /* Purge merge-parents that are out-of-graph
  */
  for(pRow=p->pFirst; pRow; pRow=pRow->pNext){
    for(i=1; i<pRow->nParent; i++){
      if( !bag_find(&allRids, pRow->aParent[i]) ){
        pRow->aParent[i] = pRow->aParent[--pRow->nParent];
        i--;
      }
    }
    if( pRow->nParent>0 && bag_find(&allRids, pRow->aParent[0]) ){
      bag_insert(&notLeaf, pRow->aParent[0]);
    }
  }

  /* Identify rows where the primary parent is off screen.  Assign
  ** each to a rail and draw descenders to the bottom of the screen.
  */
  for(pRow=p->pFirst; pRow; pRow=pRow->pNext){

    if( pDesc->aiRaiser[pDesc->iRail]==0 && pDesc->zBranch==pRow->zBranch ){
      pRow->iRail = pDesc->iRail;
    }else{
      pRow->iRail = findFreeRail(p, 0, pDesc->idx, inUse, 0);
    }
    pDesc->aiRaiser[pRow->iRail] = pRow->idx;
    mask = 1<<pRow->iRail;
    if( bag_find(&notLeaf, pRow->rid) ){
      inUse |= mask;
    }else{
      inUse &= ~mask;
    }
    for(pDesc = pRow; ; pDesc=pDesc->pNext){
      assert( pDesc!=0 );
      pDesc->railInUse |= mask;
      if( pDesc->rid==parentRid ) break;
    }
  }

    if( tagtype==2 ){
      if( zOrigUuid && zOrigUuid[0] ){
        @ inherited from
        hyperlink_to_uuid(zOrigUuid);
      }else{
        @ propagates to descendants
      }
      if( zValue && strcmp(zTagname,"branch")==0 ){
        @   
        @ <a href="%s(g.zBaseURL)/timeline?t=%T(zValue)">branch timeline</a>
      }
    }
    if( zSrcUuid && zSrcUuid[0] ){
      if( tagtype==0 ){
        @ by
      }else{
        @ added by
      }

	./translate $(SRCDIR)/zip.c >zip_.c

$(OBJDIR)/zip.o:	zip_.c zip.h  $(SRCDIR)/config.h
	$(XTCC) -o $(OBJDIR)/zip.o -c zip_.c

zip.h:	headers
$(OBJDIR)/sqlite3.o:	$(SRCDIR)/sqlite3.c
	$(XTCC) -DSQLITE_OMIT_LOAD_EXTENSION=1 -DSQLITE_THREADSAFE=0 -DSQLITE_DEFAULT_FILE_FORMAT=4 -Dlocaltime=fossil_localtime -DSQLITE_ENABLE_LOCKING_STYLE=0 -c $(SRCDIR)/sqlite3.c -o $(OBJDIR)/sqlite3.o

$(OBJDIR)/th.o:	$(SRCDIR)/th.c
	$(XTCC) -I$(SRCDIR) -c $(SRCDIR)/th.c -o $(OBJDIR)/th.o

$(OBJDIR)/th_lang.o:	$(SRCDIR)/th_lang.c
	$(XTCC) -I$(SRCDIR) -c $(SRCDIR)/th_lang.c -o $(OBJDIR)/th_lang.o

puts "\$(OBJDIR)/sqlite3.o:\t\$(SRCDIR)/sqlite3.c"
set opt {-DSQLITE_OMIT_LOAD_EXTENSION=1}
append opt " -DSQLITE_THREADSAFE=0 -DSQLITE_DEFAULT_FILE_FORMAT=4"
#append opt " -DSQLITE_ENABLE_FTS3=1"
append opt " -Dlocaltime=fossil_localtime"
append opt " -DSQLITE_ENABLE_LOCKING_STYLE=0"
puts "\t\$(XTCC) $opt -c \$(SRCDIR)/sqlite3.c -o \$(OBJDIR)/sqlite3.o\n"

puts "\$(OBJDIR)/th.o:\t\$(SRCDIR)/th.c"
puts "\t\$(XTCC) -I\$(SRCDIR) -c \$(SRCDIR)/th.c -o \$(OBJDIR)/th.o\n"

puts "\$(OBJDIR)/th_lang.o:\t\$(SRCDIR)/th_lang.c"
puts "\t\$(XTCC) -I\$(SRCDIR) -c \$(SRCDIR)/th_lang.c -o \$(OBJDIR)/th_lang.o\n"

/******************************************************************************
** This file is an amalgamation of many separate C source files from SQLite
** version 3.6.23.  By combining all the individual C code files into this 
** single large file, the entire code can be compiled as a one translation
** unit.  This allows many compilers to do optimizations that would not be
** possible if the files were compiled separately.  Performance improvements
** of 5% are 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

#ifdef HAVE_STDINT_H
#include <stdint.h>
#endif
#ifdef HAVE_INTTYPES_H
#include <inttypes.h>
#endif

/*
** The number of samples of an index that SQLite takes in order to 
** construct a histogram of the table content when running ANALYZE
** and with SQLITE_ENABLE_STAT2
*/
#define SQLITE_INDEX_SAMPLES 10

/*
** The following macros are used to cast pointers to integers and


** integers to pointers.  The way you do this varies from one compiler
** to the next, so we have developed the following set of #if statements
** to generate appropriate macros for a wide range of compilers.
**



** The correct "ANSI" way to do this is to use the intptr_t type. 
** Unfortunately, that typedef is not available on all compilers, or
** if it is available, it requires an #include of specific headers
** that very from one machine to the next.
**
** Ticket #3860:  The llvm-gcc-4.2 compiler from Apple chokes on
** the ((void*)&((char*)0)[X]) construct.  But MSVC chokes on ((void*)(X)).
** So we have to define the macros in different ways depending on the
** compiler.
*/
#if defined(__PTRDIFF_TYPE__)  /* This case should work for GCC */
# define SQLITE_INT_TO_PTR(X)  ((void*)(__PTRDIFF_TYPE__)(X))
# define SQLITE_PTR_TO_INT(X)  ((int)(__PTRDIFF_TYPE__)(X))
#elif !defined(__GNUC__)       /* Works for compilers other than LLVM */
# define SQLITE_INT_TO_PTR(X)  ((void*)&((char*)0)[X])
# define SQLITE_PTR_TO_INT(X)  ((int)(((char*)X)-(char*)0))

#elif defined(HAVE_STDINT_H)   /* Use this case if we have ANSI headers */
# define SQLITE_INT_TO_PTR(X)  ((void*)(intptr_t)(X))
# define SQLITE_PTR_TO_INT(X)  ((int)(intptr_t)(X))

#else                          /* Generates a warning - but it always works */
# define SQLITE_INT_TO_PTR(X)  ((void*)(X))
# define SQLITE_PTR_TO_INT(X)  ((int)(X))
#endif


/*
** The SQLITE_THREADSAFE macro must be defined as either 0 or 1.
** Older versions of SQLite used an optional THREADSAFE macro.
** We support that for legacy
*/
#if !defined(SQLITE_THREADSAFE)

/*
** Exactly one of the following macros must be defined in order to
** specify which memory allocation subsystem to use.
**
**     SQLITE_SYSTEM_MALLOC          // Use normal system malloc()
**     SQLITE_MEMDEBUG               // Debugging version of system malloc()
**
** (Historical note:  There used to be several other options, but we've
** pared it down to just these two.)
**
** If none of the above are defined, then set SQLITE_SYSTEM_MALLOC as
** the default.
*/
#if defined(SQLITE_SYSTEM_MALLOC)+defined(SQLITE_MEMDEBUG)>1


# error "At most one of the following compile-time configuration options\
 is allows: SQLITE_SYSTEM_MALLOC, SQLITE_MEMDEBUG"

#endif
#if defined(SQLITE_SYSTEM_MALLOC)+defined(SQLITE_MEMDEBUG)==0


# define SQLITE_SYSTEM_MALLOC 1
#endif

/*
** If SQLITE_MALLOC_SOFT_LIMIT is not zero, then try to keep the
** sizes of memory allocations below this value where possible.
*/

** 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        "3.6.23"
#define SQLITE_VERSION_NUMBER 3006023
#define SQLITE_SOURCE_ID      "2010-03-04 17:58:45 5e472896e02eed05c6c0886a48acd0bdc7a38731"

/*
** 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
** but are associated with the library instead of the header file.  ^(Cautious
** programmers might include assert() statements in their application to
** verify that values returned by these interfaces match the macros in
** the header, and thus insure that the application is

**
** ^The sqlite3_version[] string constant contains the text of [SQLITE_VERSION]
** macro.  ^The sqlite3_libversion() function returns a pointer to the
** to the sqlite3_version[] string constant.  The sqlite3_libversion()
** function is provided for use in DLLs since DLL users usually do not have
** direct access to string constants within the DLL.  ^The
** sqlite3_libversion_number() function returns an integer equal to
** [SQLITE_VERSION_NUMBER].  ^The sqlite3_sourceid() function returns 
** a pointer to a string constant whose value is the same as the 
** [SQLITE_SOURCE_ID] C preprocessor macro.
**
** See also: [sqlite_version()] and [sqlite_source_id()].
*/
SQLITE_API const char sqlite3_version[] = SQLITE_VERSION;
SQLITE_API const char *sqlite3_libversion(void);
SQLITE_API const char *sqlite3_sourceid(void);
SQLITE_API int sqlite3_libversion_number(void);

#ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS
/*
** CAPI3REF: Run-Time Library Compilation Options Diagnostics
**
** ^The sqlite3_compileoption_used() function returns 0 or 1 
** indicating whether the specified option was defined at 
** compile time.  ^The SQLITE_ prefix may be omitted from the 
** option name passed to sqlite3_compileoption_used().  
**
** ^The sqlite3_compileoption_get() function allows interating
** over the list of options that were defined at compile time by
** returning the N-th compile time option string.  ^If N is out of range,
** sqlite3_compileoption_get() returns a NULL pointer.  ^The SQLITE_ 
** prefix is omitted from any strings returned by 
** sqlite3_compileoption_get().
**
** ^Support for the diagnostic functions sqlite3_compileoption_used()
** and sqlite3_compileoption_get() may be omitted by specifing the 
** [SQLITE_OMIT_COMPILEOPTION_DIAGS] option at compile time.
**
** See also: SQL functions [sqlite_compileoption_used()] and
** [sqlite_compileoption_get()] and the [compile_options pragma].
*/
SQLITE_API int sqlite3_compileoption_used(const char *zOptName);
SQLITE_API const char *sqlite3_compileoption_get(int N);
#endif /* SQLITE_OMIT_COMPILEOPTION_DIAGS */

/*
** CAPI3REF: Test To See If The Library Is Threadsafe
**
** ^The sqlite3_threadsafe() function returns zero if and only if
** SQLite was compiled mutexing code omitted due to the
** [SQLITE_THREADSAFE] compile-time option being set to 0.
**

** [sqlite3_vfs] object.
*/
#define SQLITE_OPEN_READONLY         0x00000001  /* Ok for sqlite3_open_v2() */
#define SQLITE_OPEN_READWRITE        0x00000002  /* Ok for sqlite3_open_v2() */
#define SQLITE_OPEN_CREATE           0x00000004  /* Ok for sqlite3_open_v2() */
#define SQLITE_OPEN_DELETEONCLOSE    0x00000008  /* VFS only */
#define SQLITE_OPEN_EXCLUSIVE        0x00000010  /* VFS only */
#define SQLITE_OPEN_AUTOPROXY        0x00000020  /* VFS only */
#define SQLITE_OPEN_MAIN_DB          0x00000100  /* VFS only */
#define SQLITE_OPEN_TEMP_DB          0x00000200  /* VFS only */
#define SQLITE_OPEN_TRANSIENT_DB     0x00000400  /* VFS only */
#define SQLITE_OPEN_MAIN_JOURNAL     0x00000800  /* VFS only */
#define SQLITE_OPEN_TEMP_JOURNAL     0x00001000  /* VFS only */
#define SQLITE_OPEN_SUBJOURNAL       0x00002000  /* VFS only */
#define SQLITE_OPEN_MASTER_JOURNAL   0x00004000  /* VFS only */

SQLITE_API int sqlite3_initialize(void);
SQLITE_API int sqlite3_shutdown(void);
SQLITE_API int sqlite3_os_init(void);
SQLITE_API int sqlite3_os_end(void);

/*
** CAPI3REF: Configuring The SQLite Library

**
** The sqlite3_config() interface is used to make global configuration
** changes to SQLite in order to tune SQLite to the specific needs of
** the application.  The default configuration is recommended for most
** applications and so this routine is usually not necessary.  It is
** provided to support rare applications with unusual needs.
**

#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  /* sqlite3_pcache_methods* */
#define SQLITE_CONFIG_GETPCACHE    15  /* sqlite3_pcache_methods* */
#define SQLITE_CONFIG_LOG          16  /* xFunc, void* */

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

);
SQLITE_API int sqlite3_collation_needed16(
  sqlite3*, 
  void*,
  void(*)(void*,sqlite3*,int eTextRep,const void*)
);

#if SQLITE_HAS_CODEC
/*
** Specify the key for an encrypted database.  This routine should be
** called right after sqlite3_open().
**
** The code to implement this API is not available in the public release
** of SQLite.
*/

** of SQLite.
*/
SQLITE_API int sqlite3_rekey(
  sqlite3 *db,                   /* Database to be rekeyed */
  const void *pKey, int nKey     /* The new key */
);

/*
** Specify the activation key for a SEE database.  Unless 
** activated, none of the SEE routines will work.
*/
SQLITE_API void sqlite3_activate_see(
  const char *zPassPhrase        /* Activation phrase */
);
#endif

#ifdef SQLITE_ENABLE_CEROD
/*
** Specify the activation key for a CEROD database.  Unless 
** activated, none of the CEROD routines will work.
*/
SQLITE_API void sqlite3_activate_cerod(
  const char *zPassPhrase        /* Activation phrase */
);
#endif

/*
** CAPI3REF: Suspend Execution For A Short Time
**
** ^The sqlite3_sleep() function causes the current thread to suspend execution
** for at least a number of milliseconds specified in its parameter.
**
** ^If the operating system does not support sleep requests with

** ^The [sqlite3_strnicmp()] API allows applications and extensions to
** compare the contents of two buffers containing UTF-8 strings in a
** case-indendent fashion, using the same definition of case independence 
** that SQLite uses internally when comparing identifiers.
*/
SQLITE_API int sqlite3_strnicmp(const char *, const char *, int);

/*
** CAPI3REF: Error Logging Interface
** EXPERIMENTAL
**
** ^The [sqlite3_log()] interface writes a message into the error log
** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()].
** ^If logging is enabled, the zFormat string and subsequent arguments are
** passed through to [sqlite3_vmprintf()] to generate the final output string.
**
** The sqlite3_log() interface is intended for use by extensions such as
** virtual tables, collating functions, and SQL functions.  While there is
** nothing to prevent an application from calling sqlite3_log(), doing so
** is considered bad form.
**
** The zFormat string must not be NULL.
**
** To avoid deadlocks and other threading problems, the sqlite3_log() routine
** will not use dynamically allocated memory.  The log message is stored in
** a fixed-length buffer on the stack.  If the log message is longer than
** a few hundred characters, it will be truncated to the length of the
** buffer.
*/
SQLITE_API void sqlite3_log(int iErrCode, const char *zFormat, ...);

/*
** Undo the hack that converts floating point types to integer for
** builds on processors without floating point support.
*/
#ifdef SQLITE_OMIT_FLOATING_POINT
# undef double
#endif

*/
#ifdef SQLITE_OMIT_TEMPDB
#define OMIT_TEMPDB 1
#else
#define OMIT_TEMPDB 0
#endif















/*
** 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 1
#endif

/*
** Determine whether triggers are recursive by default.  This can be
** changed at run-time using a pragma.
*/
#ifndef SQLITE_DEFAULT_RECURSIVE_TRIGGERS
# define SQLITE_DEFAULT_RECURSIVE_TRIGGERS 0
#endif

/*
** Provide a default value for SQLITE_TEMP_STORE in case it is not specified
** on the command-line

/*
** Forward references to structures
*/
typedef struct AggInfo AggInfo;
typedef struct AuthContext AuthContext;
typedef struct AutoincInfo AutoincInfo;
typedef struct Bitvec Bitvec;

typedef struct CollSeq CollSeq;
typedef struct Column Column;
typedef struct Db Db;
typedef struct Schema Schema;
typedef struct Expr Expr;
typedef struct ExprList ExprList;
typedef struct ExprSpan ExprSpan;
typedef struct FKey FKey;
typedef struct FuncDef FuncDef;
typedef struct FuncDefHash FuncDefHash;
typedef struct IdList IdList;
typedef struct Index Index;
typedef struct IndexSample IndexSample;
typedef struct KeyClass KeyClass;
typedef struct KeyInfo KeyInfo;
typedef struct Lookaside Lookaside;
typedef struct LookasideSlot LookasideSlot;
typedef struct Module Module;
typedef struct NameContext NameContext;
typedef struct Parse Parse;
typedef struct RowSet RowSet;
typedef struct Savepoint Savepoint;
typedef struct Select Select;
typedef struct SrcList SrcList;
typedef struct StrAccum StrAccum;
typedef struct Table Table;
typedef struct TableLock TableLock;
typedef struct Token Token;
typedef struct Trigger Trigger;
typedef struct TriggerPrg TriggerPrg;
typedef struct TriggerStep TriggerStep;
typedef struct UnpackedRecord UnpackedRecord;
typedef struct VTable VTable;
typedef struct Walker Walker;
typedef struct WherePlan WherePlan;
typedef struct WhereInfo WhereInfo;
typedef struct WhereLevel WhereLevel;

SQLITE_PRIVATE int sqlite3BtreeClose(Btree*);
SQLITE_PRIVATE int sqlite3BtreeSetCacheSize(Btree*,int);
SQLITE_PRIVATE int sqlite3BtreeSetSafetyLevel(Btree*,int,int);
SQLITE_PRIVATE int sqlite3BtreeSyncDisabled(Btree*);
SQLITE_PRIVATE int sqlite3BtreeSetPageSize(Btree *p, int nPagesize, int nReserve, int eFix);
SQLITE_PRIVATE int sqlite3BtreeGetPageSize(Btree*);
SQLITE_PRIVATE int sqlite3BtreeMaxPageCount(Btree*,int);
SQLITE_PRIVATE int sqlite3BtreeSecureDelete(Btree*,int);
SQLITE_PRIVATE int sqlite3BtreeGetReserve(Btree*);
SQLITE_PRIVATE int sqlite3BtreeSetAutoVacuum(Btree *, int);
SQLITE_PRIVATE int sqlite3BtreeGetAutoVacuum(Btree *);
SQLITE_PRIVATE int sqlite3BtreeBeginTrans(Btree*,int);
SQLITE_PRIVATE int sqlite3BtreeCommitPhaseOne(Btree*, const char *zMaster);
SQLITE_PRIVATE int sqlite3BtreeCommitPhaseTwo(Btree*);
SQLITE_PRIVATE int sqlite3BtreeCommit(Btree*);

SQLITE_PRIVATE void sqlite3VdbeChangeP5(Vdbe*, u8 P5);
SQLITE_PRIVATE void sqlite3VdbeJumpHere(Vdbe*, int addr);
SQLITE_PRIVATE void sqlite3VdbeChangeToNoop(Vdbe*, int addr, int N);
SQLITE_PRIVATE void sqlite3VdbeChangeP4(Vdbe*, int addr, const char *zP4, int N);
SQLITE_PRIVATE void sqlite3VdbeUsesBtree(Vdbe*, int);
SQLITE_PRIVATE VdbeOp *sqlite3VdbeGetOp(Vdbe*, int);
SQLITE_PRIVATE int sqlite3VdbeMakeLabel(Vdbe*);
SQLITE_PRIVATE void sqlite3VdbeRunOnlyOnce(Vdbe*);
SQLITE_PRIVATE void sqlite3VdbeDelete(Vdbe*);
SQLITE_PRIVATE void sqlite3VdbeMakeReady(Vdbe*,int,int,int,int,int,int);
SQLITE_PRIVATE int sqlite3VdbeFinalize(Vdbe*);
SQLITE_PRIVATE void sqlite3VdbeResolveLabel(Vdbe*, int);
SQLITE_PRIVATE int sqlite3VdbeCurrentAddr(Vdbe*);
#ifdef SQLITE_DEBUG
SQLITE_PRIVATE   int sqlite3VdbeAssertMayAbort(Vdbe *, int);

#ifndef SQLITE_OMIT_VIRTUALTABLE
  sqlite3 *db;         /* "Owner" connection. See comment above */
#endif
};

/*
** These macros can be used to test, set, or clear bits in the 
** Db.pSchema->flags field.
*/
#define DbHasProperty(D,I,P)     (((D)->aDb[I].pSchema->flags&(P))==(P))
#define DbHasAnyProperty(D,I,P)  (((D)->aDb[I].pSchema->flags&(P))!=0)
#define DbSetProperty(D,I,P)     (D)->aDb[I].pSchema->flags|=(P)
#define DbClearProperty(D,I,P)   (D)->aDb[I].pSchema->flags&=~(P)

/*
** Allowed values for the DB.pSchema->flags field.
**
** The DB_SchemaLoaded flag is set after the database schema has been
** read into internal hash tables.
**
** DB_UnresetViews means that one or more views have column names that
** have been filled out.  If the schema changes, these column names might
** changes and so the view will need to be reset.

** Collisions are on the FuncDef.pHash chain.
*/
struct FuncDefHash {
  FuncDef *a[23];       /* Hash table for functions */
};

/*
** Each database connection is an instance of the following structure.
**
** The sqlite.lastRowid records the last insert rowid generated by an
** insert statement.  Inserts on views do not affect its value.  Each
** trigger has its own context, so that lastRowid can be updated inside
** triggers as usual.  The previous value will be restored once the trigger
** exits.  Upon entering a before or instead of trigger, lastRowid is no
** longer (since after version 2.8.12) reset to -1.

  int errMask;                  /* & result codes with this before returning */
  u8 autoCommit;                /* The auto-commit flag. */
  u8 temp_store;                /* 1: file 2: memory 0: default */
  u8 mallocFailed;              /* True if we have seen a malloc failure */
  u8 dfltLockMode;              /* Default locking-mode for attached dbs */
  u8 dfltJournalMode;           /* Default journal mode for attached dbs */
  signed char nextAutovac;      /* Autovac setting after VACUUM if >=0 */
  u8 suppressErr;               /* Do not issue error messages if true */
  int nextPagesize;             /* Pagesize after VACUUM if >0 */
  int nTable;                   /* Number of tables in the database */
  CollSeq *pDfltColl;           /* The default collating sequence (BINARY) */
  i64 lastRowid;                /* ROWID of most recent insert (see above) */
  u32 magic;                    /* Magic number for detect library misuse */
  int nChange;                  /* Value returned by sqlite3_changes() */
  int nTotalChange;             /* Value returned by sqlite3_total_changes() */

  int isInit;                       /* True after initialization has finished */
  int inProgress;                   /* True while initialization in progress */
  int isMutexInit;                  /* True after mutexes are initialized */
  int isMallocInit;                 /* True after malloc is initialized */
  int isPCacheInit;                 /* True after malloc is initialized */
  sqlite3_mutex *pInitMutex;        /* Mutex used by sqlite3_initialize() */
  int nRefInitMutex;                /* Number of users of pInitMutex */
  void (*xLog)(void*,int,const char*); /* Function for logging */
  void *pLogArg;                       /* First argument to xLog() */
};

/*
** Context pointer passed down through the tree-walk.
*/
struct Walker {
  int (*xExprCallback)(Walker*, Expr*);     /* Callback for expressions */

#define SQLITE_SKIP_UTF8(zIn) {                        \
  if( (*(zIn++))>=0xc0 ){                              \
    while( (*zIn & 0xc0)==0x80 ){ zIn++; }             \
  }                                                    \
}

/*
** The SQLITE_*_BKPT macros are substitutes for the error codes with
** the same name but without the _BKPT suffix.  These macros invoke
** routines that report the line-number on which the error originated
** using sqlite3_log().  The routines also provide a convenient place
** to set a debugger breakpoint.

*/
SQLITE_PRIVATE int sqlite3CorruptError(int);
SQLITE_PRIVATE int sqlite3MisuseError(int);
SQLITE_PRIVATE int sqlite3CantopenError(int);
#define SQLITE_CORRUPT_BKPT sqlite3CorruptError(__LINE__)
#define SQLITE_MISUSE_BKPT sqlite3MisuseError(__LINE__)
#define SQLITE_CANTOPEN_BKPT sqlite3CantopenError(__LINE__)


/*
** FTS4 is really an extension for FTS3.  It is enabled using the
** SQLITE_ENABLE_FTS3 macro.  But to avoid confusion we also all
** the SQLITE_ENABLE_FTS4 macro to serve as an alisse for SQLITE_ENABLE_FTS3.
*/
#if defined(SQLITE_ENABLE_FTS4) && !defined(SQLITE_ENABLE_FTS3)
# define SQLITE_ENABLE_FTS3
#endif

/*
** The ctype.h header is needed for non-ASCII systems.  It is also
** needed by FTS3 when FTS3 is included in the amalgamation.
*/
#if !defined(SQLITE_ASCII) || \

SQLITE_PRIVATE   int sqlite3MutexEnd(void);
#endif

SQLITE_PRIVATE int sqlite3StatusValue(int);
SQLITE_PRIVATE void sqlite3StatusAdd(int, int);
SQLITE_PRIVATE void sqlite3StatusSet(int, int);

#ifndef SQLITE_OMIT_FLOATING_POINT
SQLITE_PRIVATE   int sqlite3IsNaN(double);
#else
# define sqlite3IsNaN(X)  0
#endif

SQLITE_PRIVATE void sqlite3VXPrintf(StrAccum*, int, const char*, va_list);
#ifndef SQLITE_OMIT_TRACE
SQLITE_PRIVATE void sqlite3XPrintf(StrAccum*, const char*, ...);
#endif
SQLITE_PRIVATE char *sqlite3MPrintf(sqlite3*,const char*, ...);
SQLITE_PRIVATE char *sqlite3VMPrintf(sqlite3*,const char*, va_list);
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
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 IdList *sqlite3IdListDup(sqlite3*,IdList*);
SQLITE_PRIVATE Select *sqlite3SelectDup(sqlite3*,Select*,int);
SQLITE_PRIVATE void sqlite3FuncDefInsert(FuncDefHash*, FuncDef*);
SQLITE_PRIVATE FuncDef *sqlite3FindFunction(sqlite3*,const char*,int,int,u8,int);
SQLITE_PRIVATE void sqlite3RegisterBuiltinFunctions(sqlite3*);
SQLITE_PRIVATE void sqlite3RegisterDateTimeFunctions(void);
SQLITE_PRIVATE void sqlite3RegisterGlobalFunctions(void);







SQLITE_PRIVATE int sqlite3SafetyCheckOk(sqlite3*);
SQLITE_PRIVATE int sqlite3SafetyCheckSickOrOk(sqlite3*);
SQLITE_PRIVATE void sqlite3ChangeCookie(Parse*, int);

#if !defined(SQLITE_OMIT_VIEW) && !defined(SQLITE_OMIT_TRIGGER)
SQLITE_PRIVATE void sqlite3MaterializeView(Parse*, Table*, Expr*, int);
#endif

   0,                         /* isInit */
   0,                         /* inProgress */
   0,                         /* isMutexInit */
   0,                         /* isMallocInit */
   0,                         /* isPCacheInit */
   0,                         /* pInitMutex */
   0,                         /* nRefInitMutex */
   0,                         /* xLog */
   0,                         /* pLogArg */
};


/*
** Hash table for global functions - functions common to all
** database connections.  After initialization, this table is
** read-only.

** This implementation assumes that reading or writing an aligned
** 32-bit integer is an atomic operation.  If that assumption is not true,
** then this routine is not threadsafe.
*/
SQLITE_API int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag){
  wsdStatInit;
  if( op<0 || op>=ArraySize(wsdStat.nowValue) ){
    return SQLITE_MISUSE_BKPT;
  }
  *pCurrent = wsdStat.nowValue[op];
  *pHighwater = wsdStat.mxValue[op];
  if( resetFlag ){
    wsdStat.mxValue[op] = wsdStat.nowValue[op];
  }
  return SQLITE_OK;

    FUNCTION(datetime,         -1, 0, 0, datetimeFunc  ),
    FUNCTION(strftime,         -1, 0, 0, strftimeFunc  ),
    FUNCTION(current_time,      0, 0, 0, ctimeFunc     ),
    FUNCTION(current_timestamp, 0, 0, 0, ctimestampFunc),
    FUNCTION(current_date,      0, 0, 0, cdateFunc     ),
#else
    STR_FUNCTION(current_time,      0, "%H:%M:%S",          0, currentTimeFunc),
    STR_FUNCTION(current_date,      0, "%Y-%m-%d",          0, currentTimeFunc),
    STR_FUNCTION(current_timestamp, 0, "%Y-%m-%d %H:%M:%S", 0, currentTimeFunc),
#endif
  };
  int i;
  FuncDefHash *pHash = &GLOBAL(FuncDefHash, sqlite3GlobalFunctions);
  FuncDef *aFunc = (FuncDef*)&GLOBAL(FuncDef, aDateTimeFuncs);

  for(i=0; i<ArraySize(aDateTimeFuncs); i++){

  const char *zPath, 
  sqlite3_file *pFile, 
  int flags, 
  int *pFlagsOut
){
  int rc;
  DO_OS_MALLOC_TEST(0);
  /* 0x7f3f is a mask of SQLITE_OPEN_ flags that are valid to be passed
  ** down into the VFS layer.  Some SQLITE_OPEN_ flags (for example,
  ** SQLITE_OPEN_FULLMUTEX or SQLITE_OPEN_SHAREDCACHE) are blocked before
  ** reaching the VFS. */
  rc = pVfs->xOpen(pVfs, zPath, pFile, flags & 0x7f3f, pFlagsOut);
  assert( rc==SQLITE_OK || pFile->pMethods==0 );
  return rc;
}
SQLITE_PRIVATE int sqlite3OsDelete(sqlite3_vfs *pVfs, const char *zPath, int dirSync){
  return pVfs->xDelete(pVfs, zPath, dirSync);
}
SQLITE_PRIVATE int sqlite3OsAccess(

  sqlite3_int64 *p;
  assert( nByte>0 );
  nByte = ROUND8(nByte);
  p = 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;
}

/*
** 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){
  sqlite3_int64 *p = (sqlite3_int64*)pPrior;
  assert( pPrior!=0 );
  p--;
  free(p);
}

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

/*
** 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){
  sqlite3_int64 *p = (sqlite3_int64*)pPrior;
  assert( pPrior!=0 && nByte>0 );
  nByte = ROUND8(nByte);

  p--;
  p = 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;
}













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

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

/*
** Fill a buffer with pseudo-random bytes.  This is used to preset
** the content of a new memory allocation to unpredictable values and
** to clear the content of a freed allocation to unpredictable values.
*/
static void randomFill(char *pBuf, int nByte){
  unsigned int x, y, r;
  x = SQLITE_PTR_TO_INT(pBuf);
  y = nByte | 1;
  while( nByte >= 4 ){
    x = (x>>1) ^ (-(x&1) & 0xd0000001);
    y = y*1103515245 + 12345;
    r = x ^ y;
    *(int*)pBuf = r;
    pBuf += 4;
    nByte -= 4;
  }
  while( nByte-- > 0 ){
    x = (x>>1) ^ (-(x&1) & 0xd0000001);
    y = y*1103515245 + 12345;
    r = x ^ y;
    *(pBuf++) = r & 0xff;
  }
}

/*
** Allocate nByte bytes of memory.
*/
static void *sqlite3MemMalloc(int nByte){
  struct MemBlockHdr *pHdr;
  void **pBt;

    if( mem.nTitle ){
      memcpy(z, mem.zTitle, mem.nTitle);
    }
    pHdr->iSize = nByte;
    adjustStats(nByte, +1);
    pInt = (int*)&pHdr[1];
    pInt[nReserve/sizeof(int)] = REARGUARD;
    randomFill((char*)pInt, nByte);
    memset(((char*)pInt)+nByte, 0x65, nReserve-nByte);
    p = (void*)pInt;
  }
  sqlite3_mutex_leave(mem.mutex);
  return p; 
}

/*

  }else{
    assert( mem.pLast==pHdr );
    mem.pLast = pHdr->pPrev;
  }
  z = (char*)pBt;
  z -= pHdr->nTitle;
  adjustStats(pHdr->iSize, -1);
  randomFill(z, sizeof(void*)*pHdr->nBacktraceSlots + sizeof(*pHdr) +
                pHdr->iSize + sizeof(int) + pHdr->nTitle);
  free(z);
  sqlite3_mutex_leave(mem.mutex);  
}

/*
** Change the size of an existing memory allocation.
**

  void *pNew;
  assert( mem.disallow==0 );
  pOldHdr = sqlite3MemsysGetHeader(pPrior);
  pNew = sqlite3MemMalloc(nByte);
  if( pNew ){
    memcpy(pNew, pPrior, nByte<pOldHdr->iSize ? nByte : pOldHdr->iSize);
    if( nByte>pOldHdr->iSize ){
      randomFill(&((char*)pNew)[pOldHdr->iSize], nByte - pOldHdr->iSize);
    }
    sqlite3MemFree(pPrior);
  }
  return pNew;
}

/*

  for(iFullSz=mem5.szAtom, iLogsize=0; iFullSz<nByte; iFullSz *= 2, iLogsize++){}

  /* Make sure mem5.aiFreelist[iLogsize] contains at least one free
  ** block.  If not, then split a block of the next larger power of
  ** two in order to create a new free block of size iLogsize.
  */
  for(iBin=iLogsize; mem5.aiFreelist[iBin]<0 && iBin<=LOGMAX; iBin++){}
  if( iBin>LOGMAX ){
    testcase( sqlite3GlobalConfig.xLog!=0 );
    sqlite3_log(SQLITE_NOMEM, "failed to allocate %u bytes", nByte);
    return 0;
  }
  i = memsys5UnlinkFirst(iBin);
  while( iBin>iLogsize ){
    int newSize;

    iBin--;
    newSize = 1 << iBin;
    mem5.aCtrl[i+newSize] = CTRL_FREE | iBin;

** Each recursive mutex is an instance of the following structure.
*/
struct sqlite3_mutex {
  CRITICAL_SECTION mutex;    /* Mutex controlling the lock */
  int id;                    /* Mutex type */
  int nRef;                  /* Number of enterances */
  DWORD owner;               /* Thread holding this mutex */
#ifdef SQLITE_DEBUG
  int trace;                 /* True to trace changes */
#endif
};
#define SQLITE_W32_MUTEX_INITIALIZER { 0 }
#ifdef SQLITE_DEBUG
#define SQLITE3_MUTEX_INITIALIZER { SQLITE_W32_MUTEX_INITIALIZER, 0, 0L, (DWORD)0, 0 }
#else
#define SQLITE3_MUTEX_INITIALIZER { SQLITE_W32_MUTEX_INITIALIZER, 0, 0L, (DWORD)0 }
#endif

/*
** 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

#ifdef SQLITE_DEBUG
/*
** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routine are
** intended for use only inside assert() statements.
*/
static int winMutexHeld(sqlite3_mutex *p){
  return p->nRef!=0 && p->owner==GetCurrentThreadId();
}
static int winMutexNotheld2(sqlite3_mutex *p, DWORD tid){
  return p->nRef==0 || p->owner!=tid;
}
static int winMutexNotheld(sqlite3_mutex *p){
  DWORD tid = GetCurrentThreadId(); 
  return winMutexNotheld2(p, tid);
}
#endif


/*
** Initialize and deinitialize the mutex subsystem.
*/
static sqlite3_mutex winMutex_staticMutexes[6] = {
  SQLITE3_MUTEX_INITIALIZER,
  SQLITE3_MUTEX_INITIALIZER,
  SQLITE3_MUTEX_INITIALIZER,
  SQLITE3_MUTEX_INITIALIZER,
  SQLITE3_MUTEX_INITIALIZER,
  SQLITE3_MUTEX_INITIALIZER
};
static int winMutex_isInit = 0;
/* As winMutexInit() and winMutexEnd() are called as part
** of the sqlite3_initialize and sqlite3_shutdown()
** processing, the "interlocked" magic is probably not
** strictly necessary.
*/
static long winMutex_lock = 0;

** upon successful entry.  Mutexes created using SQLITE_MUTEX_RECURSIVE can
** be entered multiple times by the same thread.  In such cases the,
** mutex must be exited an equal number of times before another thread
** can enter.  If the same thread tries to enter any other kind of mutex
** more than once, the behavior is undefined.
*/
static void winMutexEnter(sqlite3_mutex *p){
  DWORD tid = GetCurrentThreadId(); 
  assert( p->id==SQLITE_MUTEX_RECURSIVE || winMutexNotheld2(p, tid) );
  EnterCriticalSection(&p->mutex);
  p->owner = tid; 
  p->nRef++;
#ifdef SQLITE_DEBUG
  if( p->trace ){
    printf("enter mutex %p (%d) with nRef=%d\n", p, p->trace, p->nRef);
  }
#endif
}
static int winMutexTry(sqlite3_mutex *p){
  DWORD tid = GetCurrentThreadId(); 
  int rc = SQLITE_BUSY;
  assert( p->id==SQLITE_MUTEX_RECURSIVE || winMutexNotheld2(p, tid) );
  /*
  ** The sqlite3_mutex_try() routine is very rarely used, and when it
  ** is used it is merely an optimization.  So it is OK for it to always
  ** fail.  
  **
  ** The TryEnterCriticalSection() interface is only available on WinNT.
  ** And some windows compilers complain if you try to use it without
  ** first doing some #defines that prevent SQLite from building on Win98.
  ** For that reason, we will omit this optimization for now.  See
  ** ticket #2685.
  */
#if 0
  if( mutexIsNT() && TryEnterCriticalSection(&p->mutex) ){
    p->owner = tid;
    p->nRef++;
    rc = SQLITE_OK;
  }
#else
  UNUSED_PARAMETER(p);
#endif
#ifdef SQLITE_DEBUG
  if( rc==SQLITE_OK && p->trace ){
    printf("enter mutex %p (%d) with nRef=%d\n", p, p->trace, p->nRef);
  }
#endif
  return rc;
}

/*
** The sqlite3_mutex_leave() routine exits a mutex that was
** previously entered by the same thread.  The behavior
** is undefined if the mutex is not currently entered or
** is not currently allocated.  SQLite will never do either.
*/
static void winMutexLeave(sqlite3_mutex *p){
  DWORD tid = GetCurrentThreadId(); 
  assert( p->nRef>0 );
  assert( p->owner==tid );
  p->nRef--;
  assert( p->nRef==0 || p->id==SQLITE_MUTEX_RECURSIVE );
  LeaveCriticalSection(&p->mutex);
#ifdef SQLITE_DEBUG
  if( p->trace ){
    printf("leave mutex %p (%d) with nRef=%d\n", p, p->trace, p->nRef);
  }
#endif
}

SQLITE_PRIVATE sqlite3_mutex_methods *sqlite3DefaultMutex(void){
  static sqlite3_mutex_methods sMutex = {
    winMutexInit,
    winMutexEnd,
    winMutexAlloc,

        }
        length = (int)(&buf[etBUFSIZE-1]-bufpt);
        break;
      case etFLOAT:
      case etEXP:
      case etGENERIC:
        realvalue = va_arg(ap,double);
#ifdef SQLITE_OMIT_FLOATING_POINT
        length = 0;
#else
        if( precision<0 ) precision = 6;         /* Set default precision */
        if( precision>etBUFSIZE/2-10 ) precision = etBUFSIZE/2-10;
        if( realvalue<0.0 ){
          realvalue = -realvalue;
          prefix = '-';
        }else{
          if( flag_plussign )          prefix = '+';

          for(i=width; i>=nPad; i--){
            bufpt[i] = bufpt[i-nPad];
          }
          i = prefix!=0;
          while( nPad-- ) bufpt[i++] = '0';
          length = width;
        }
#endif /* !defined(SQLITE_OMIT_FLOATING_POINT) */
        break;
      case etSIZE:
        *(va_arg(ap,int*)) = pAccum->nChar;
        length = width = 0;
        break;
      case etPERCENT:
        buf[0] = '%';

        int needQuote;
        char ch;
        char q = ((xtype==etSQLESCAPE3)?'"':'\'');   /* Quote character */
        char *escarg = va_arg(ap,char*);
        isnull = escarg==0;
        if( isnull ) escarg = (xtype==etSQLESCAPE2 ? "NULL" : "(NULL)");
        k = precision;
        for(i=n=0; k!=0 && (ch=escarg[i])!=0; i++, k--){
          if( ch==q )  n++;
        }
        needQuote = !isnull && xtype==etSQLESCAPE2;
        n += i + 1 + needQuote*2;
        if( n>etBUFSIZE ){
          bufpt = zExtra = sqlite3Malloc( n );
          if( bufpt==0 ){

  acc.useMalloc = 0;
  va_start(ap,zFormat);
  sqlite3VXPrintf(&acc, 0, zFormat, ap);
  va_end(ap);
  z = sqlite3StrAccumFinish(&acc);
  return z;
}

/*
** This is the routine that actually formats the sqlite3_log() message.
** We house it in a separate routine from sqlite3_log() to avoid using
** stack space on small-stack systems when logging is disabled.
**
** sqlite3_log() must render into a static buffer.  It cannot dynamically
** allocate memory because it might be called while the memory allocator
** mutex is held.
*/
static void renderLogMsg(int iErrCode, const char *zFormat, va_list ap){
  StrAccum acc;                          /* String accumulator */
  char zMsg[SQLITE_PRINT_BUF_SIZE*3];    /* Complete log message */

  sqlite3StrAccumInit(&acc, zMsg, sizeof(zMsg), 0);
  acc.useMalloc = 0;
  sqlite3VXPrintf(&acc, 0, zFormat, ap);
  sqlite3GlobalConfig.xLog(sqlite3GlobalConfig.pLogArg, iErrCode,
                           sqlite3StrAccumFinish(&acc));
}

/*
** Format and write a message to the log if logging is enabled.
*/
SQLITE_API void sqlite3_log(int iErrCode, const char *zFormat, ...){
  va_list ap;                             /* Vararg list */
  if( sqlite3GlobalConfig.xLog ){
    va_start(ap, zFormat);
    renderLogMsg(iErrCode, zFormat, ap);
    va_end(ap);
  }
}

#if defined(SQLITE_DEBUG)
/*
** A version of printf() that understands %lld.  Used for debugging.
** The printf() built into some versions of windows does not understand %lld
** and segfaults if you give it a long long int.
*/

  u32 cacheCtr;           /* VdbeCursor row cache generation counter */
  int pc;                 /* The program counter */
  int rc;                 /* Value to return */
  char *zErrMsg;          /* Error message written here */
  u8 explain;             /* True if EXPLAIN present on SQL command */
  u8 changeCntOn;         /* True to update the change-counter */
  u8 expired;             /* True if the VM needs to be recompiled */
  u8 runOnlyOnce;         /* Automatically expire on reset */
  u8 minWriteFileFormat;  /* Minimum file format for writable database files */
  u8 inVtabMethod;        /* See comments above */
  u8 usesStmtJournal;     /* True if uses a statement journal */
  u8 readOnly;            /* True for read-only statements */
  u8 isPrepareV2;         /* True if prepared with prepare_v2() */
  int nChange;            /* Number of db changes made since last reset */
  int btreeMask;          /* Bitmask of db->aDb[] entries referenced */

SQLITE_PRIVATE int sqlite3VdbeMemTooBig(Mem*);
SQLITE_PRIVATE int sqlite3VdbeMemCopy(Mem*, const Mem*);
SQLITE_PRIVATE void sqlite3VdbeMemShallowCopy(Mem*, const Mem*, int);
SQLITE_PRIVATE void sqlite3VdbeMemMove(Mem*, Mem*);
SQLITE_PRIVATE int sqlite3VdbeMemNulTerminate(Mem*);
SQLITE_PRIVATE int sqlite3VdbeMemSetStr(Mem*, const char*, int, u8, void(*)(void*));
SQLITE_PRIVATE void sqlite3VdbeMemSetInt64(Mem*, i64);
#ifdef SQLITE_OMIT_FLOATING_POINT
# define sqlite3VdbeMemSetDouble sqlite3VdbeMemSetInt64
#else
SQLITE_PRIVATE   void sqlite3VdbeMemSetDouble(Mem*, double);
#endif
SQLITE_PRIVATE void sqlite3VdbeMemSetNull(Mem*);
SQLITE_PRIVATE void sqlite3VdbeMemSetZeroBlob(Mem*,int);
SQLITE_PRIVATE void sqlite3VdbeMemSetRowSet(Mem*);
SQLITE_PRIVATE int sqlite3VdbeMemMakeWriteable(Mem*);
SQLITE_PRIVATE int sqlite3VdbeMemStringify(Mem*, int);
SQLITE_PRIVATE i64 sqlite3VdbeIntValue(Mem*);
SQLITE_PRIVATE int sqlite3VdbeMemIntegerify(Mem*);

#ifdef SQLITE_COVERAGE_TEST
SQLITE_PRIVATE void sqlite3Coverage(int x){
  static int dummy = 0;
  dummy += x;
}
#endif

#ifndef SQLITE_OMIT_FLOATING_POINT
/*
** Return true if the floating point value is Not a Number (NaN).
**
** Use the math library isnan() function if compiled with SQLITE_HAVE_ISNAN.
** Otherwise, we have our own implementation that works on most systems.
*/
SQLITE_PRIVATE int sqlite3IsNaN(double x){

  rc = (y!=z);
#else  /* if defined(SQLITE_HAVE_ISNAN) */
  rc = isnan(x);
#endif /* SQLITE_HAVE_ISNAN */
  testcase( rc );
  return rc;
}
#endif /* SQLITE_OMIT_FLOATING_POINT */

/*
** Compute a string length that is limited to what can be stored in
** lower 30 bits of a 32-bit signed integer.
**
** The value returned will never be negative.  Nor will it ever be greater
** than the actual length of the string.  For very long strings (greater

** compiling an SQL statement (i.e. within sqlite3_prepare()). The
** last thing the sqlite3_prepare() function does is copy the error
** stored by this function into the database handle using sqlite3Error().
** Function sqlite3Error() should be used during statement execution
** (sqlite3_step() etc.).
*/
SQLITE_PRIVATE void sqlite3ErrorMsg(Parse *pParse, const char *zFormat, ...){
  char *zMsg;
  va_list ap;
  sqlite3 *db = pParse->db;


  va_start(ap, zFormat);
  zMsg = sqlite3VMPrintf(db, zFormat, ap);
  va_end(ap);
  if( db->suppressErr ){
    sqlite3DbFree(db, zMsg);
  }else{
    pParse->nErr++;




    sqlite3DbFree(db, pParse->zErrMsg);
    pParse->zErrMsg = zMsg;
    pParse->rc = SQLITE_ERROR;
  }
}

/*
** Convert an SQL-style quoted string into a normal string by removing
** the quote characters.  The conversion is done in-place.  If the
** input does not begin with a quote character, then this routine
** is a no-op.

  if( *z=='-' || *z=='+' ) z += incr;
  if( !sqlite3Isdigit(*z) ){
    return 0;
  }
  z += incr;
  *realnum = 0;
  while( sqlite3Isdigit(*z) ){ z += incr; }
#ifndef SQLITE_OMIT_FLOATING_POINT
  if( *z=='.' ){
    z += incr;
    if( !sqlite3Isdigit(*z) ) return 0;
    while( sqlite3Isdigit(*z) ){ z += incr; }
    *realnum = 1;
  }
  if( *z=='e' || *z=='E' ){
    z += incr;
    if( *z=='+' || *z=='-' ) z += incr;
    if( !sqlite3Isdigit(*z) ) return 0;
    while( sqlite3Isdigit(*z) ){ z += incr; }
    *realnum = 1;
  }
#endif
  return *z==0;
}

/*
** The string z[] is an ASCII representation of a real number.
** Convert this string to a double.
**

** will return -8.
*/
static int compare2pow63(const char *zNum){
  int c;
  c = memcmp(zNum,"922337203685477580",18)*10;
  if( c==0 ){
    c = zNum[18] - '8';
    testcase( c==(-1) );
    testcase( c==0 );
    testcase( c==(+1) );
  }
  return c;
}


/*
** Return TRUE if zNum is a 64-bit signed integer and write

  }
  zStart = zNum;
  while( zNum[0]=='0' ){ zNum++; } /* Skip over leading zeros. Ticket #2454 */
  for(i=0; (c=zNum[i])>='0' && c<='9'; i++){
    v = v*10 + c - '0';
  }
  *pNum = neg ? -v : v;
  testcase( i==18 );
  testcase( i==19 );
  testcase( i==20 );
  if( c!=0 || (i==0 && zStart==zNum) || i>19 ){
    /* zNum is empty or contains non-numeric text or is longer
    ** than 19 digits (thus guaranting that it is too large) */
    return 0;
  }else if( i<19 ){
    /* Less than 19 digits, so we know that it fits in 64 bits */
    return 1;

  assert( zNum[0]>='0' && zNum[0]<='9' ); /* zNum is an unsigned number */

  if( negFlag ) neg = 1-neg;
  while( *zNum=='0' ){
    zNum++;   /* Skip leading zeros.  Ticket #2454 */
  }
  for(i=0; zNum[i]; i++){ assert( zNum[i]>='0' && zNum[i]<='9' ); }
  testcase( i==18 );
  testcase( i==19 );
  testcase( i==20 );
  if( i<19 ){
    /* Guaranteed to fit if less than 19 digits */
    return 1;
  }else if( i>19 ){
    /* Guaranteed to be too big if greater than 19 digits */
    return 0;
  }else{

  }

  /* The longest decimal representation of a 32 bit integer is 10 digits:
  **
  **             1234567890
  **     2^31 -> 2147483648
  */
  testcase( i==10 );
  if( i>10 ){
    return 0;
  }
  testcase( v-neg==2147483647 );
  if( v-neg>2147483647 ){
    return 0;
  }
  if( neg ){
    v = -v;
  }
  *pValue = (int)v;

  if( (v & ~0x3fff)==0 ){
    p[0] = (u8)((v>>7) | 0x80);
    p[1] = (u8)(v & 0x7f);
    return 2;
  }
  return sqlite3PutVarint(p, v);
}

/*
** Bitmasks used by sqlite3GetVarint().  These precomputed constants
** are defined here rather than simply putting the constant expressions
** inline in order to work around bugs in the RVT compiler.
**
** SLOT_2_0     A mask for  (0x7f<<14) | 0x7f
**
** SLOT_4_2_0   A mask for  (0x7f<<28) | SLOT_2_0
*/
#define SLOT_2_0     0x001fc07f
#define SLOT_4_2_0   0xf01fc07f


/*
** Read a 64-bit variable-length integer from memory starting at p[0].
** Return the number of bytes read.  The value is stored in *v.
*/
SQLITE_PRIVATE u8 sqlite3GetVarint(const unsigned char *p, u64 *v){
  u32 a,b,s;

    a &= 0x7f;
    a = a<<7;
    a |= b;
    *v = a;
    return 2;
  }

  /* Verify that constants are precomputed correctly */
  assert( SLOT_2_0 == ((0x7f<<14) | (0x7f)) );
  assert( SLOT_4_2_0 == ((0xf<<28) | (0x7f<<14) | (0x7f)) );

  p++;
  a = a<<14;
  a |= *p;
  /* a: p0<<14 | p2 (unmasked) */
  if (!(a&0x80))
  {
    a &= SLOT_2_0;
    b &= 0x7f;
    b = b<<7;
    a |= b;
    *v = a;
    return 3;
  }

  /* CSE1 from below */
  a &= SLOT_2_0;
  p++;
  b = b<<14;
  b |= *p;
  /* b: p1<<14 | p3 (unmasked) */
  if (!(b&0x80))
  {
    b &= SLOT_2_0;
    /* moved CSE1 up */
    /* a &= (0x7f<<14)|(0x7f); */
    a = a<<7;
    a |= b;
    *v = a;
    return 4;
  }

  /* a: p0<<14 | p2 (masked) */
  /* b: p1<<14 | p3 (unmasked) */
  /* 1:save off p0<<21 | p1<<14 | p2<<7 | p3 (masked) */
  /* moved CSE1 up */
  /* a &= (0x7f<<14)|(0x7f); */
  b &= SLOT_2_0;
  s = a;
  /* s: p0<<14 | p2 (masked) */

  p++;
  a = a<<14;
  a |= *p;
  /* a: p0<<28 | p2<<14 | p4 (unmasked) */

  b = b<<14;
  b |= *p;
  /* b: p1<<28 | p3<<14 | p5 (unmasked) */
  if (!(b&0x80))
  {
    /* we can skip this cause it was (effectively) done above in calc'ing s */
    /* b &= (0x7f<<28)|(0x7f<<14)|(0x7f); */
    a &= SLOT_2_0;
    a = a<<7;
    a |= b;
    s = s>>18;
    *v = ((u64)s)<<32 | a;
    return 6;
  }

  p++;
  a = a<<14;
  a |= *p;
  /* a: p2<<28 | p4<<14 | p6 (unmasked) */
  if (!(a&0x80))
  {
    a &= SLOT_4_2_0;
    b &= SLOT_2_0;
    b = b<<7;
    a |= b;
    s = s>>11;
    *v = ((u64)s)<<32 | a;
    return 7;
  }

  /* CSE2 from below */
  a &= SLOT_2_0;
  p++;
  b = b<<14;
  b |= *p;
  /* b: p3<<28 | p5<<14 | p7 (unmasked) */
  if (!(b&0x80))
  {
    b &= SLOT_4_2_0;
    /* moved CSE2 up */
    /* a &= (0x7f<<14)|(0x7f); */
    a = a<<7;
    a |= b;
    s = s>>4;
    *v = ((u64)s)<<32 | a;
    return 8;
  }

  p++;
  a = a<<15;
  a |= *p;
  /* a: p4<<29 | p6<<15 | p8 (unmasked) */

  /* moved CSE2 up */
  /* a &= (0x7f<<29)|(0x7f<<15)|(0xff); */
  b &= SLOT_2_0;
  b = b<<8;
  a |= b;

  s = s<<4;
  b = p[-4];
  b &= 0x7f;
  b = b>>3;

  p++;
  a = a<<14;
  a |= *p;
  /* a: p0<<28 | p2<<14 | p4 (unmasked) */
  if (!(a&0x80))
  {
    /* Values  between 268435456 and 34359738367 */
    a &= SLOT_4_2_0;
    b &= SLOT_4_2_0;
    b = b<<7;
    *v = a | b;
    return 5;
  }

  /* We can only reach this point when reading a corrupt database
  ** file.  In that case we are not in any hurry.  Use the (relatively

    }
    zBlob[i/2] = 0;
  }
  return zBlob;
}
#endif /* !SQLITE_OMIT_BLOB_LITERAL || SQLITE_HAS_CODEC */


/*

** Log an error that is an API call on a connection pointer that should



** not have been used.  The "type" of connection pointer is given as the








** argument.  The zType is a word like "NULL" or "closed" or "invalid".








*/













static void logBadConnection(const char *zType){





  sqlite3_log(SQLITE_MISUSE, 







     "API call with %s database connection pointer",

     zType
  );
}



/*
** Check to make sure we have a valid db pointer.  This test is not
** foolproof but it does provide some measure of protection against
** misuse of the interface such as passing in db pointers that are
** NULL or which have been previously closed.  If this routine returns
** 1 it means that the db pointer is valid and 0 if it should not be
** dereferenced for any reason.  The calling function should invoke
** SQLITE_MISUSE immediately.
**
** sqlite3SafetyCheckOk() requires that the db pointer be valid for
** use.  sqlite3SafetyCheckSickOrOk() allows a db pointer that failed to
** open properly and is not fit for general use but which can be
** used as an argument to sqlite3_errmsg() or sqlite3_close().
*/
SQLITE_PRIVATE int sqlite3SafetyCheckOk(sqlite3 *db){
  u32 magic;
  if( db==0 ){
    logBadConnection("NULL");
    return 0;
  }
  magic = db->magic;
  if( magic!=SQLITE_MAGIC_OPEN ){


    if( sqlite3SafetyCheckSickOrOk(db) ){
      testcase( sqlite3GlobalConfig.xLog!=0 );
      logBadConnection("unopened");

    }
    return 0;
  }else{
    return 1;
  }
}
SQLITE_PRIVATE int sqlite3SafetyCheckSickOrOk(sqlite3 *db){
  u32 magic;
  magic = db->magic;
  if( magic!=SQLITE_MAGIC_SICK &&
      magic!=SQLITE_MAGIC_OPEN &&
      magic!=SQLITE_MAGIC_BUSY ){
    testcase( sqlite3GlobalConfig.xLog!=0 );
    logBadConnection("invalid");
    return 0;
  }else{
    return 1;
  }
}

/************** End of util.c ************************************************/
/************** Begin file hash.c ********************************************/
/*
** 2001 September 22
**

# else
#  include <sys/file.h>
#  include <sys/param.h>
#  include <sys/mount.h>
# endif
#endif /* SQLITE_ENABLE_LOCKING_STYLE */

/*
** Allowed values of unixFile.fsFlags
*/
#define SQLITE_FSFLAGS_IS_MSDOS     0x1

/*
** If we are to be thread-safe, include the pthreads header and define
** the SQLITE_UNIX_THREADS macro.
*/
#if SQLITE_THREADSAFE
# define SQLITE_UNIX_THREADS 1
#endif

  int lastErrno;                   /* The unix errno from the last I/O error */
  void *lockingContext;            /* Locking style specific state */
  UnixUnusedFd *pUnused;           /* Pre-allocated UnixUnusedFd */
  int fileFlags;                   /* Miscellanous flags */
#if SQLITE_ENABLE_LOCKING_STYLE
  int openFlags;                   /* The flags specified at open() */
#endif
#if SQLITE_ENABLE_LOCKING_STYLE || defined(__APPLE__)
  unsigned fsFlags;                 /* cached details from statfs() */
#endif
#if SQLITE_THREADSAFE && defined(__linux__)
  pthread_t tid;                   /* The thread that "owns" this unixFile */
#endif
#if OS_VXWORKS
  int isDelete;                    /* Delete on close if true */
  struct vxworksFileId *pId;       /* Unique file ID */
#endif

** object keeps a count of the number of unixFile pointing to it.
*/
struct unixLockInfo {
  struct unixLockKey lockKey;     /* The lookup key */
  int cnt;                        /* Number of SHARED locks held */
  int locktype;                   /* One of SHARED_LOCK, RESERVED_LOCK etc. */
  int nRef;                       /* Number of pointers to this structure */
#if defined(SQLITE_ENABLE_LOCKING_STYLE)
  unsigned long long sharedByte;  /* for AFP simulated shared lock */
#endif
  struct unixLockInfo *pNext;     /* List of all unixLockInfo objects */
  struct unixLockInfo *pPrev;     /*    .... doubly linked */
};

/*
** An instance of the following structure is allocated for each open
** inode.  This structure keeps track of the number of locks on that

  ** we always increase the file size to 1 by writing a single byte
  ** prior to accessing the inode number.  The one byte written is
  ** an ASCII 'S' character which also happens to be the first byte
  ** in the header of every SQLite database.  In this way, if there
  ** is a race condition such that another thread has already populated
  ** the first page of the database, no damage is done.
  */
  if( statbuf.st_size==0 && (pFile->fsFlags & SQLITE_FSFLAGS_IS_MSDOS)!=0 ){
    rc = write(fd, "S", 1);
    if( rc!=1 ){
      pFile->lastErrno = errno;
      return SQLITE_IOERR;
    }
    rc = fstat(fd, &statbuf);
    if( rc!=0 ){
      pFile->lastErrno = errno;
      return SQLITE_IOERR;
    }

        rc = SQLITE_NOMEM;
        goto exit_findlockinfo;
      }
      memcpy(&pLock->lockKey,&lockKey,sizeof(lockKey));
      pLock->nRef = 1;
      pLock->cnt = 0;
      pLock->locktype = 0;
#if defined(SQLITE_ENABLE_LOCKING_STYLE)
      pLock->sharedByte = 0;
#endif
      pLock->pNext = lockList;
      pLock->pPrev = 0;
      if( lockList ) lockList->pPrev = pLock;
      lockList = pLock;
    }else{
      pLock->nRef++;
    }

  if( pthread_equal(pFile->tid, hSelf) ){
    /* We are still in the same thread */
    OSTRACE1("No-transfer, same thread\n");
    return SQLITE_OK;
  }
  if( pFile->locktype!=NO_LOCK ){
    /* We cannot change ownership while we are holding a lock! */
    return SQLITE_MISUSE_BKPT;
  }
  OSTRACE4("Transfer ownership of %d from %d to %d\n",
            pFile->h, pFile->tid, hSelf);
  pFile->tid = hSelf;
  if (pFile->pLock != NULL) {
    releaseLockInfo(pFile->pLock);
    rc = findLockInfo(pFile, &pFile->pLock, 0);

  }
#endif
  
  unixLeaveMutex();
  OSTRACE4("TEST WR-LOCK %d %d %d (unix)\n", pFile->h, rc, reserved);

  *pResOut = reserved;
























































  return rc;
}

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

  ** even if the locking primitive used is always a write-lock.
  */
  int rc = SQLITE_OK;
  unixFile *pFile = (unixFile*)id;
  struct unixLockInfo *pLock = pFile->pLock;
  struct flock lock;
  int s = 0;
  int tErrno = 0;

  assert( pFile );
  OSTRACE7("LOCK    %d %s was %s(%s,%d) pid=%d (unix)\n", pFile->h,
      locktypeName(locktype), locktypeName(pFile->locktype),
      locktypeName(pLock->locktype), pLock->cnt , getpid());

  /* If there is already a lock of this type or more restrictive on the

  ** operating system calls for the specified lock.
  */
  if( locktype==SHARED_LOCK ){
    assert( pLock->cnt==0 );
    assert( pLock->locktype==0 );

    /* Now get the read-lock */
    lock.l_start = SHARED_FIRST;
    lock.l_len = SHARED_SIZE;
    if( (s = fcntl(pFile->h, F_SETLK, &lock))==(-1) ){
      tErrno = errno;
    }
    /* Drop the temporary PENDING lock */
    lock.l_start = PENDING_BYTE;
    lock.l_len = 1L;
    lock.l_type = F_UNLCK;
    if( fcntl(pFile->h, F_SETLK, &lock)!=0 ){
      if( s != -1 ){
        /* This could happen with a network mount */

    ** already.
    */
    assert( 0!=pFile->locktype );
    lock.l_type = F_WRLCK;
    switch( locktype ){
      case RESERVED_LOCK:
        lock.l_start = RESERVED_BYTE;


        break;
      case EXCLUSIVE_LOCK:

        lock.l_start = SHARED_FIRST;
        lock.l_len = SHARED_SIZE;
        break;
      default:
        assert(0);
    }
    s = fcntl(pFile->h, F_SETLK, &lock);
    if( s==(-1) ){
      tErrno = errno;
      rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_LOCK);
      if( IS_LOCK_ERROR(rc) ){
        pFile->lastErrno = tErrno;
      }
    }
  }
  

/*
** Lower the locking level on file descriptor pFile to locktype.  locktype
** 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.
** 
** If handleNFSUnlock is true, then on downgrading an EXCLUSIVE_LOCK to SHARED
** the byte range is divided into 2 parts and the first part is unlocked then
** set to a read lock, then the other part is simply unlocked.  This works 
** around a bug in BSD NFS lockd (also seen on MacOSX 10.3+) that fails to 
** remove the write lock on a region when a read lock is set.
*/
static int _posixUnlock(sqlite3_file *id, int locktype, int handleNFSUnlock){
  unixFile *pFile = (unixFile*)id;
  struct unixLockInfo *pLock;
  struct flock lock;
  int rc = SQLITE_OK;
  int h;
  int tErrno;                      /* Error code from system call errors */

  assert( pFile );
  OSTRACE7("UNLOCK  %d %d was %d(%d,%d) pid=%d (unix)\n", pFile->h, locktype,
      pFile->locktype, pFile->pLock->locktype, pFile->pLock->cnt, getpid());

  assert( locktype<=SHARED_LOCK );
  if( pFile->locktype<=locktype ){
    return SQLITE_OK;
  }
  if( CHECK_THREADID(pFile) ){
    return SQLITE_MISUSE_BKPT;
  }
  unixEnterMutex();
  h = pFile->h;
  pLock = pFile->pLock;
  assert( pLock->cnt!=0 );
  if( pFile->locktype>SHARED_LOCK ){
    assert( pLock->locktype==pFile->locktype );

    */
    assert( pFile->inNormalWrite==0
         || pFile->dbUpdate==0
         || pFile->transCntrChng==1 );
    pFile->inNormalWrite = 0;
#endif

    /* downgrading to a shared lock on NFS involves clearing the write lock
    ** before establishing the readlock - to avoid a race condition we downgrade
    ** the lock in 2 blocks, so that part of the range will be covered by a 
    ** write lock until the rest is covered by a read lock:
    **  1:   [WWWWW]
    **  2:   [....W]
    **  3:   [RRRRW]
    **  4:   [RRRR.]
    */
    if( locktype==SHARED_LOCK ){
      if( handleNFSUnlock ){
        off_t divSize = SHARED_SIZE - 1;
        
        lock.l_type = F_UNLCK;
        lock.l_whence = SEEK_SET;
        lock.l_start = SHARED_FIRST;
        lock.l_len = divSize;
        if( fcntl(h, F_SETLK, &lock)==(-1) ){
          tErrno = errno;
          rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_UNLOCK);
          if( IS_LOCK_ERROR(rc) ){
            pFile->lastErrno = tErrno;
          }
          goto end_unlock;
        }
        lock.l_type = F_RDLCK;
        lock.l_whence = SEEK_SET;
        lock.l_start = SHARED_FIRST;
        lock.l_len = divSize;
        if( fcntl(h, F_SETLK, &lock)==(-1) ){
          tErrno = errno;
          rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_RDLOCK);
          if( IS_LOCK_ERROR(rc) ){
            pFile->lastErrno = tErrno;
          }
          goto end_unlock;
        }
        lock.l_type = F_UNLCK;
        lock.l_whence = SEEK_SET;
        lock.l_start = SHARED_FIRST+divSize;
        lock.l_len = SHARED_SIZE-divSize;
        if( fcntl(h, F_SETLK, &lock)==(-1) ){
          tErrno = errno;
          rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_UNLOCK);
          if( IS_LOCK_ERROR(rc) ){
            pFile->lastErrno = tErrno;
          }
          goto end_unlock;
        }
      }else{
        lock.l_type = F_RDLCK;
        lock.l_whence = SEEK_SET;
        lock.l_start = SHARED_FIRST;
        lock.l_len = SHARED_SIZE;
        if( fcntl(h, F_SETLK, &lock)==(-1) ){
          tErrno = errno;
          rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_RDLOCK);
          if( IS_LOCK_ERROR(rc) ){
            pFile->lastErrno = tErrno;
          }
          goto end_unlock;
        }
      }
    }
    lock.l_type = F_UNLCK;
    lock.l_whence = SEEK_SET;
    lock.l_start = PENDING_BYTE;
    lock.l_len = 2L;  assert( PENDING_BYTE+1==RESERVED_BYTE );
    if( fcntl(h, F_SETLK, &lock)!=(-1) ){

  }
	
end_unlock:
  unixLeaveMutex();
  if( rc==SQLITE_OK ) pFile->locktype = locktype;
  return rc;
}

/*
** Lower the locking level on file descriptor pFile to locktype.  locktype
** 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.
*/
static int unixUnlock(sqlite3_file *id, int locktype){
  return _posixUnlock(id, locktype, 0);
}

/*
** This function performs the parts of the "close file" operation 
** common to all locking schemes. It closes the directory and file
** handles, if they are valid, and sets all fields of the unixFile
** structure to 0.
**

#if defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE
/*
** The afpLockingContext structure contains all afp lock specific state
*/
typedef struct afpLockingContext afpLockingContext;
struct afpLockingContext {
  int reserved;
  const char *dbPath;             /* Name of the open file */
};

struct ByteRangeLockPB2
{
  unsigned long long offset;        /* offset to first byte to lock */
  unsigned long long length;        /* nbr of bytes to lock */

  int reserved = 0;
  unixFile *pFile = (unixFile*)id;
  
  SimulateIOError( return SQLITE_IOERR_CHECKRESERVEDLOCK; );
  
  assert( pFile );
  afpLockingContext *context = (afpLockingContext *) pFile->lockingContext;
  if( context->reserved ){
    *pResOut = 1;
    return SQLITE_OK;
  }
  unixEnterMutex(); /* Because pFile->pLock is shared across threads */
  
  /* Check if a thread in this process holds such a lock */
  if( pFile->pLock->locktype>SHARED_LOCK ){
    reserved = 1;
  }
  
  /* Otherwise see if some other process holds it.
   */
  if( !reserved ){
    /* lock the RESERVED byte */

      reserved = 1;
    }
    if( IS_LOCK_ERROR(lrc) ){
      rc=lrc;
    }
  }
  
  unixLeaveMutex();
  OSTRACE4("TEST WR-LOCK %d %d %d (afp)\n", pFile->h, rc, reserved);
  
  *pResOut = reserved;
  return rc;
}

/*

**
** This routine will only increase a lock.  Use the sqlite3OsUnlock()
** routine to lower a locking level.
*/
static int afpLock(sqlite3_file *id, int locktype){
  int rc = SQLITE_OK;
  unixFile *pFile = (unixFile*)id;
  struct unixLockInfo *pLock = pFile->pLock;
  afpLockingContext *context = (afpLockingContext *) pFile->lockingContext;
  
  assert( pFile );
  OSTRACE7("LOCK    %d %s was %s(%s,%d) pid=%d (afp)\n", pFile->h,
           locktypeName(locktype), locktypeName(pFile->locktype),
           locktypeName(pLock->locktype), pLock->cnt , getpid());

  /* If there is already a lock of this type or more restrictive on the
  ** unixFile, do nothing. Don't use the afp_end_lock: exit path, as
  ** unixEnterMutex() hasn't been called yet.
  */
  if( pFile->locktype>=locktype ){
    OSTRACE3("LOCK    %d %s ok (already held) (afp)\n", pFile->h,
           locktypeName(locktype));
    return SQLITE_OK;
  }

  /* Make sure the locking sequence is correct
  **  (1) We never move from unlocked to anything higher than shared lock.
  **  (2) SQLite never explicitly requests a pendig lock.
  **  (3) A shared lock is always held when a reserve lock is requested.
  */
  assert( pFile->locktype!=NO_LOCK || locktype==SHARED_LOCK );
  assert( locktype!=PENDING_LOCK );
  assert( locktype!=RESERVED_LOCK || pFile->locktype==SHARED_LOCK );
  
  /* This mutex is needed because pFile->pLock is shared across threads
  */
  unixEnterMutex();

  /* Make sure the current thread owns the pFile.
  */
  rc = transferOwnership(pFile);
  if( rc!=SQLITE_OK ){
    unixLeaveMutex();
    return rc;
  }
  pLock = pFile->pLock;

  /* If some thread using this PID has a lock via a different unixFile*
  ** handle that precludes the requested lock, return BUSY.
  */
  if( (pFile->locktype!=pLock->locktype && 
       (pLock->locktype>=PENDING_LOCK || locktype>SHARED_LOCK))
     ){
    rc = SQLITE_BUSY;
    goto afp_end_lock;
  }
  
  /* If a SHARED lock is requested, and some thread using this PID already
  ** has a SHARED or RESERVED lock, then increment reference counts and
  ** return SQLITE_OK.
  */
  if( locktype==SHARED_LOCK && 
     (pLock->locktype==SHARED_LOCK || pLock->locktype==RESERVED_LOCK) ){
    assert( locktype==SHARED_LOCK );
    assert( pFile->locktype==0 );
    assert( pLock->cnt>0 );
    pFile->locktype = SHARED_LOCK;
    pLock->cnt++;
    pFile->pOpen->nLock++;
    goto afp_end_lock;
  }
    
  /* A PENDING lock is needed before acquiring a SHARED lock and before
  ** acquiring an EXCLUSIVE lock.  For the SHARED lock, the PENDING will
  ** be released.
  */
  if( locktype==SHARED_LOCK 

    }
  }
  
  /* If control gets to this point, then actually go ahead and make
  ** operating system calls for the specified lock.
  */
  if( locktype==SHARED_LOCK ){
    int lrc1, lrc2, lrc1Errno;
    long lk, mask;
    
    assert( pLock->cnt==0 );
    assert( pLock->locktype==0 );
        
    mask = (sizeof(long)==8) ? LARGEST_INT64 : 0x7fffffff;
    /* Now get the read-lock SHARED_LOCK */
    /* note that the quality of the randomness doesn't matter that much */
    lk = random(); 
    pLock->sharedByte = (lk & mask)%(SHARED_SIZE - 1);
    lrc1 = afpSetLock(context->dbPath, pFile, 
          SHARED_FIRST+pLock->sharedByte, 1, 1);
    if( IS_LOCK_ERROR(lrc1) ){
      lrc1Errno = pFile->lastErrno;
    }
    /* Drop the temporary PENDING lock */
    lrc2 = afpSetLock(context->dbPath, pFile, PENDING_BYTE, 1, 0);
    
    if( IS_LOCK_ERROR(lrc1) ) {
      pFile->lastErrno = lrc1Errno;
      rc = lrc1;
      goto afp_end_lock;
    } else if( IS_LOCK_ERROR(lrc2) ){
      rc = lrc2;
      goto afp_end_lock;
    } else if( lrc1 != SQLITE_OK ) {
      rc = lrc1;
    } else {
      pFile->locktype = SHARED_LOCK;
      pFile->pOpen->nLock++;
      pLock->cnt = 1;
    }
  }else if( locktype==EXCLUSIVE_LOCK && pLock->cnt>1 ){
    /* We are trying for an exclusive lock but another thread in this
     ** same process is still holding a shared lock. */
    rc = SQLITE_BUSY;
  }else{
    /* The request was for a RESERVED or EXCLUSIVE lock.  It is
    ** assumed that there is a SHARED or greater lock on the file
    ** already.
    */
    int failed = 0;
    assert( 0!=pFile->locktype );
    if (locktype >= RESERVED_LOCK && pFile->locktype < RESERVED_LOCK) {
        /* Acquire a RESERVED lock */
        failed = afpSetLock(context->dbPath, pFile, RESERVED_BYTE, 1,1);
      if( !failed ){
        context->reserved = 1;
      }
    }
    if (!failed && locktype == EXCLUSIVE_LOCK) {
      /* Acquire an EXCLUSIVE lock */
        
      /* Remove the shared lock before trying the range.  we'll need to 
      ** reestablish the shared lock if we can't get the  afpUnlock
      */
      if( !(failed = afpSetLock(context->dbPath, pFile, SHARED_FIRST +
                         pLock->sharedByte, 1, 0)) ){
        int failed2 = SQLITE_OK;
        /* now attemmpt to get the exclusive lock range */
        failed = afpSetLock(context->dbPath, pFile, SHARED_FIRST, 
                               SHARED_SIZE, 1);
        if( failed && (failed2 = afpSetLock(context->dbPath, pFile, 
                       SHARED_FIRST + pLock->sharedByte, 1, 1)) ){
          /* Can't reestablish the shared lock.  Sqlite can't deal, this is
          ** a critical I/O error
          */
          rc = ((failed & SQLITE_IOERR) == SQLITE_IOERR) ? failed2 : 
               SQLITE_IOERR_LOCK;
          goto afp_end_lock;
        } 
      }else{
        rc = failed; 
      }
    }
    if( failed ){
      rc = failed;
    }
  }
  
  if( rc==SQLITE_OK ){
    pFile->locktype = locktype;
    pLock->locktype = locktype;
  }else if( locktype==EXCLUSIVE_LOCK ){
    pFile->locktype = PENDING_LOCK;
    pLock->locktype = PENDING_LOCK;
  }
  
afp_end_lock:
  unixLeaveMutex();
  OSTRACE4("LOCK    %d %s %s (afp)\n", pFile->h, locktypeName(locktype), 
         rc==SQLITE_OK ? "ok" : "failed");
  return rc;
}

/*
** Lower the locking level on file descriptor pFile to locktype.  locktype
** 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.
*/
static int afpUnlock(sqlite3_file *id, int locktype) {
  int rc = SQLITE_OK;
  unixFile *pFile = (unixFile*)id;
  struct unixLockInfo *pLock;
  afpLockingContext *context = (afpLockingContext *) pFile->lockingContext;
  int skipShared = 0;
#ifdef SQLITE_TEST
  int h = pFile->h;
#endif

  assert( pFile );
  OSTRACE7("UNLOCK  %d %d was %d(%d,%d) pid=%d (afp)\n", pFile->h, locktype,
           pFile->locktype, pFile->pLock->locktype, pFile->pLock->cnt, getpid());

  assert( locktype<=SHARED_LOCK );
  if( pFile->locktype<=locktype ){
    return SQLITE_OK;
  }
  if( CHECK_THREADID(pFile) ){
    return SQLITE_MISUSE_BKPT;
  }
  unixEnterMutex();
  pLock = pFile->pLock;
  assert( pLock->cnt!=0 );
  if( pFile->locktype>SHARED_LOCK ){
    assert( pLock->locktype==pFile->locktype );
    SimulateIOErrorBenign(1);
    SimulateIOError( h=(-1) )
    SimulateIOErrorBenign(0);
    
#ifndef NDEBUG
    /* When reducing a lock such that other processes can start
    ** reading the database file again, make sure that the
    ** transaction counter was updated if any part of the database
    ** file changed.  If the transaction counter is not updated,
    ** other connections to the same file might not realize that
    ** the file has changed and hence might not know to flush their
    ** cache.  The use of a stale cache can lead to database corruption.
    */
    assert( pFile->inNormalWrite==0
           || pFile->dbUpdate==0
           || pFile->transCntrChng==1 );
    pFile->inNormalWrite = 0;
#endif
    
    if( pFile->locktype==EXCLUSIVE_LOCK ){
      rc = afpSetLock(context->dbPath, pFile, SHARED_FIRST, SHARED_SIZE, 0);
      if( rc==SQLITE_OK && (locktype==SHARED_LOCK || pLock->cnt>1) ){
        /* only re-establish the shared lock if necessary */
        int sharedLockByte = SHARED_FIRST+pLock->sharedByte;
        rc = afpSetLock(context->dbPath, pFile, sharedLockByte, 1, 1);
      } else {
        skipShared = 1;
      }
    }
    if( rc==SQLITE_OK && pFile->locktype>=PENDING_LOCK ){
      rc = afpSetLock(context->dbPath, pFile, PENDING_BYTE, 1, 0);
    } 
    if( rc==SQLITE_OK && pFile->locktype>=RESERVED_LOCK && context->reserved ){
      rc = afpSetLock(context->dbPath, pFile, RESERVED_BYTE, 1, 0);
      if( !rc ){ 
        context->reserved = 0; 
      }
    }
    if( rc==SQLITE_OK && (locktype==SHARED_LOCK || pLock->cnt>1)){
      pLock->locktype = SHARED_LOCK;
    }
  }
  if( rc==SQLITE_OK && locktype==NO_LOCK ){

    /* Decrement the shared lock counter.  Release the lock using an
    ** OS call only when all threads in this same process have released
    ** the lock.
    */
    unsigned long long sharedLockByte = SHARED_FIRST+pLock->sharedByte;
    pLock->cnt--;
    if( pLock->cnt==0 ){
      SimulateIOErrorBenign(1);
      SimulateIOError( h=(-1) )
      SimulateIOErrorBenign(0);
      if( !skipShared ){
        rc = afpSetLock(context->dbPath, pFile, sharedLockByte, 1, 0);
      }
      if( !rc ){
        pLock->locktype = NO_LOCK;
        pFile->locktype = NO_LOCK;
      }
    }
    if( rc==SQLITE_OK ){

      struct unixOpenCnt *pOpen = pFile->pOpen;
        
      pOpen->nLock--;
      assert( pOpen->nLock>=0 );
      if( pOpen->nLock==0 ){
        rc = closePendingFds(pFile);
      }
    }
  }
  
  unixLeaveMutex();
  if( rc==SQLITE_OK ) pFile->locktype = locktype;


  return rc;
}

/*
** Close a file & cleanup AFP specific locking context 
*/
static int afpClose(sqlite3_file *id) {
  int rc = SQLITE_OK;
  if( id ){
    unixFile *pFile = (unixFile*)id;
    afpUnlock(id, NO_LOCK);
    unixEnterMutex();
    if( pFile->pOpen && pFile->pOpen->nLock ){
      /* If there are outstanding locks, do not actually close the file just
      ** yet because that would clear those locks.  Instead, add the file
      ** descriptor to pOpen->aPending.  It will be automatically closed when
      ** the last lock is cleared.
      */
      setPendingFd(pFile);
    }
    releaseLockInfo(pFile->pLock);
    releaseOpenCnt(pFile->pOpen);
    sqlite3_free(pFile->lockingContext);
    rc = closeUnixFile(id);
    unixLeaveMutex();
  }
  return rc;
}

#endif /* defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE */
/*
** The code above is the AFP lock implementation.  The code is specific
** to MacOSX and does not work on other unix platforms.  No alternative
** is available.  If you don't compile for a mac, then the "unix-afp"
** VFS is not available.
**
********************* End of the AFP lock implementation **********************
******************************************************************************/

/******************************************************************************
*************************** Begin NFS Locking ********************************/

#if defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE
/*
 ** Lower the locking level on file descriptor pFile to locktype.  locktype
 ** 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.
 */
static int nfsUnlock(sqlite3_file *id, int locktype){
  return _posixUnlock(id, locktype, 1);
}

#endif /* defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE */
/*
** The code above is the NFS lock implementation.  The code is specific
** to MacOSX and does not work on other unix platforms.  No alternative
** is available.  
**
********************* End of the NFS lock implementation **********************
******************************************************************************/

/******************************************************************************
**************** Non-locking sqlite3_file methods *****************************
**
** The next division contains implementations for all methods of the 
** sqlite3_file object other than the locking methods.  The locking
** methods were defined in divisions above (one locking method per

** 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;
#if (!defined(USE_PREAD) && !defined(USE_PREAD64))
  i64 newOffset;
#endif
  TIMER_START;
#if defined(USE_PREAD)
  got = pread(id->h, pBuf, cnt, offset);
  SimulateIOError( got = -1 );
#elif defined(USE_PREAD64)
  got = pread64(id->h, pBuf, cnt, offset);
  SimulateIOError( got = -1 );

** Return the number of bytes actually read.  Update the offset.
**
** To avoid stomping the errno value on a failed write the lastErrno value
** is set before returning.
*/
static int seekAndWrite(unixFile *id, i64 offset, const void *pBuf, int cnt){
  int got;
#if (!defined(USE_PREAD) && !defined(USE_PREAD64))
  i64 newOffset;
#endif
  TIMER_START;
#if defined(USE_PREAD)
  got = pwrite(id->h, pBuf, cnt, offset);
#elif defined(USE_PREAD64)
  got = pwrite64(id->h, pBuf, cnt, offset);
#else
  newOffset = lseek(id->h, offset, SEEK_SET);

  ** isn't supported for this file system. So, attempt an fsync 
  ** and (for now) ignore the overhead of a superfluous fcntl call.  
  ** It'd be better to detect fullfsync support once and avoid 
  ** the fcntl call every time sync is called.
  */
  if( rc ) rc = fsync(fd);

#elif defined(__APPLE__)
  /* fdatasync() on HFS+ doesn't yet flush the file size if it changed correctly
  ** so currently we default to the macro that redefines fdatasync to fsync
  */
  rc = fsync(fd);
#else 
  rc = fdatasync(fd);
#if OS_VXWORKS
  if( rc==-1 && errno==ENOTSUP ){
    rc = fsync(fd);
  }
#endif /* OS_VXWORKS */

  afpClose,                 /* xClose method */
  afpLock,                  /* xLock method */
  afpUnlock,                /* xUnlock method */
  afpCheckReservedLock      /* xCheckReservedLock method */
)
#endif


















/*
** The proxy locking method is a "super-method" in the sense that it
** opens secondary file descriptors for the conch and lock files and
** it uses proxy, dot-file, AFP, and flock() locking methods on those
** secondary files.  For this reason, the division that implements
** proxy locking is located much further down in the file.  But we need
** to go ahead and define the sqlite3_io_methods and finder function

  proxyClose,               /* xClose method */
  proxyLock,                /* xLock method */
  proxyUnlock,              /* xUnlock method */
  proxyCheckReservedLock    /* xCheckReservedLock method */
)
#endif

/* nfs lockd on OSX 10.3+ doesn't clear write locks when a read lock is set */
#if defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE
IOMETHODS(
  nfsIoFinder,               /* Finder function name */
  nfsIoMethods,              /* sqlite3_io_methods object name */
  unixClose,                 /* xClose method */
  unixLock,                  /* xLock method */
  nfsUnlock,                 /* xUnlock method */
  unixCheckReservedLock      /* xCheckReservedLock method */
)
#endif

#if defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE
/* 
** This "finder" function attempts to determine the best locking strategy 
** for the database file "filePath".  It then returns the sqlite3_io_methods
** object that implements that strategy.
**
** This is for MacOSX only.
*/
static const sqlite3_io_methods *autolockIoFinderImpl(
  const char *filePath,    /* name of the database file */
  unixFile *pNew           /* open file object for the database file */
){
  static const struct Mapping {
    const char *zFilesystem;              /* Filesystem type name */
    const sqlite3_io_methods *pMethods;   /* Appropriate locking method */
  } aMap[] = {
    { "hfs",    &posixIoMethods },
    { "ufs",    &posixIoMethods },
    { "afpfs",  &afpIoMethods },

    { "smbfs",  &afpIoMethods },



    { "webdav", &nolockIoMethods },
    { 0, 0 }
  };
  int i;
  struct statfs fsInfo;
  struct flock lockInfo;

  ** assume that the file-system supports POSIX style locks. 
  */
  lockInfo.l_len = 1;
  lockInfo.l_start = 0;
  lockInfo.l_whence = SEEK_SET;
  lockInfo.l_type = F_RDLCK;
  if( fcntl(pNew->h, F_GETLK, &lockInfo)!=-1 ) {
    if( strcmp(fsInfo.f_fstypename, "nfs")==0 ){
      return &nfsIoMethods;
    } else {
      return &posixIoMethods;
    }
  }else{
    return &dotlockIoMethods;
  }
}
static const sqlite3_io_methods 
  *(*const autolockIoFinder)(const char*,unixFile*) = autolockIoFinderImpl;

    /* Cache zFilename in the locking context (AFP and dotlock override) for
    ** proxyLock activation is possible (remote proxy is based on db name)
    ** zFilename remains valid until file is closed, to support */
    pNew->lockingContext = (void*)zFilename;
#endif
  }

  if( pLockingStyle == &posixIoMethods
#if defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE
    || pLockingStyle == &nfsIoMethods
#endif
  ){
    unixEnterMutex();
    rc = findLockInfo(pNew, &pNew->pLock, &pNew->pOpen);
    if( rc!=SQLITE_OK ){
      /* If an error occured in findLockInfo(), close the file descriptor
      ** immediately, before releasing the mutex. findLockInfo() may fail
      ** in two scenarios:
      **

    if( pCtx==0 ){
      rc = SQLITE_NOMEM;
    }else{
      /* NB: zFilename exists and remains valid until the file is closed
      ** according to requirement F11141.  So we do not need to make a
      ** copy of the filename. */
      pCtx->dbPath = zFilename;
      pCtx->reserved = 0;
      srandomdev();
      unixEnterMutex();
      rc = findLockInfo(pNew, &pNew->pLock, &pNew->pOpen);
      if( rc!=SQLITE_OK ){
        sqlite3_free(pNew->lockingContext);
        close(h);
        h = -1;
      }
      unixLeaveMutex();        
    }
  }
#endif

  else if( pLockingStyle == &dotlockIoMethods ){
    /* Dotfile locking uses the file path so it needs to be included in

    unixLeaveMutex();
  }
#endif
  
  pNew->lastErrno = 0;
#if OS_VXWORKS
  if( rc!=SQLITE_OK ){
    if( h>=0 ) close(h);
    h = -1;
    unlink(zFilename);
    isDelete = 0;
  }
  pNew->isDelete = isDelete;
#endif
  if( rc!=SQLITE_OK ){
    if( dirfd>=0 ) close(dirfd); /* silent leak if fail, already in error */

#ifdef FD_CLOEXEC
      fcntl(fd, F_SETFD, fcntl(fd, F_GETFD, 0) | FD_CLOEXEC);
#endif
      OSTRACE3("OPENDIR %-3d %s\n", fd, zDirname);
    }
  }
  *pFd = fd;
  return (fd>=0?SQLITE_OK:SQLITE_CANTOPEN_BKPT);
}

/*
** Create a temporary file name in zBuf.  zBuf must be allocated
** by the calling process and must be big enough to hold at least
** pVfs->mxPathname bytes.
*/

  ** For this reason, if an error occurs in the stat() call here, it is
  ** ignored and -1 is returned. The caller will try to open a new file
  ** descriptor on the same path, fail, and return an error to SQLite.
  **
  ** Even if a subsequent open() call does succeed, the consequences of
  ** not searching for a resusable file descriptor are not dire.  */
  if( 0==stat(zPath, &sStat) ){
    struct unixOpenCnt *pOpen;




    unixEnterMutex();
    pOpen = openList;
    while( pOpen && (pOpen->fileId.dev!=sStat.st_dev
                     || pOpen->fileId.ino!=sStat.st_ino) ){
       pOpen = pOpen->pNext;
    }
    if( pOpen ){
      UnixUnusedFd **pp;
      for(pp=&pOpen->pUnused; *pp && (*pp)->flags!=flags; pp=&((*pp)->pNext));
      pUnused = *pp;
      if( pUnused ){
        *pp = pUnused->pNext;
      }
    }
    unixLeaveMutex();
  }

  int rc = SQLITE_OK;            /* Function Return Code */

  int isExclusive  = (flags & SQLITE_OPEN_EXCLUSIVE);
  int isDelete     = (flags & SQLITE_OPEN_DELETEONCLOSE);
  int isCreate     = (flags & SQLITE_OPEN_CREATE);
  int isReadonly   = (flags & SQLITE_OPEN_READONLY);
  int isReadWrite  = (flags & SQLITE_OPEN_READWRITE);
#if SQLITE_ENABLE_LOCKING_STYLE
  int isAutoProxy  = (flags & SQLITE_OPEN_AUTOPROXY);
#endif

  /* If creating a master or main-file journal, this function will open
  ** a file-descriptor on the directory too. The first time unixSync()
  ** is called the directory file descriptor will be fsync()ed and close()d.
  */
  int isOpenDirectory = (isCreate && 
      (eType==SQLITE_OPEN_MASTER_JOURNAL || eType==SQLITE_OPEN_MAIN_JOURNAL)

      flags &= ~(SQLITE_OPEN_READWRITE|SQLITE_OPEN_CREATE);
      openFlags &= ~(O_RDWR|O_CREAT);
      flags |= SQLITE_OPEN_READONLY;
      openFlags |= O_RDONLY;
      fd = open(zName, openFlags, openMode);
    }
    if( fd<0 ){
      rc = SQLITE_CANTOPEN_BKPT;
      goto open_finished;
    }
  }
  assert( fd>=0 );
  if( pOutFlags ){
    *pOutFlags = flags;
  }

#ifdef FD_CLOEXEC
  fcntl(fd, F_SETFD, fcntl(fd, F_GETFD, 0) | FD_CLOEXEC);
#endif

  noLock = eType!=SQLITE_OPEN_MAIN_DB;

  
#if defined(__APPLE__) || SQLITE_ENABLE_LOCKING_STYLE
  struct statfs fsInfo;
  if( fstatfs(fd, &fsInfo) == -1 ){
    ((unixFile*)pFile)->lastErrno = errno;
    if( dirfd>=0 ) close(dirfd); /* silently leak if fail, in error */
    close(fd); /* silently leak if fail, in error */
    return SQLITE_IOERR_ACCESS;
  }
  if (0 == strncmp("msdos", fsInfo.f_fstypename, 5)) {
    ((unixFile*)pFile)->fsFlags |= SQLITE_FSFLAGS_IS_MSDOS;
  }
#endif
  
#if SQLITE_ENABLE_LOCKING_STYLE
#if SQLITE_PREFER_PROXY_LOCKING
  isAutoProxy = 1;
#endif
  if( isAutoProxy && (zPath!=NULL) && (!noLock) && pVfs->xOpen ){
    char *envforce = getenv("SQLITE_FORCE_PROXY_LOCKING");
    int useProxy = 0;

    /* SQLITE_FORCE_PROXY_LOCKING==1 means force always use proxy, 0 means 
    ** never use proxy, NULL means use proxy for non-local files only.  */
    if( envforce!=NULL ){
      useProxy = atoi(envforce)>0;

      }
      useProxy = !(fsInfo.f_flags&MNT_LOCAL);
    }
    if( useProxy ){
      rc = fillInUnixFile(pVfs, fd, dirfd, pFile, zPath, noLock, isDelete);
      if( rc==SQLITE_OK ){
        rc = proxyTransformUnixFile((unixFile*)pFile, ":auto:");
        if( rc!=SQLITE_OK ){
          /* Use unixClose to clean up the resources added in fillInUnixFile 
          ** and clear all the structure's references.  Specifically, 
          ** pFile->pMethods will be NULL so sqlite3OsClose will be a no-op 
          */
          unixClose(pFile);
          return rc;
        }
      }
      goto open_finished;
    }
  }
#endif
  
  rc = fillInUnixFile(pVfs, fd, dirfd, pFile, zPath, noLock, isDelete);

  zOut[nOut-1] = '\0';
  if( zPath[0]=='/' ){
    sqlite3_snprintf(nOut, zOut, "%s", zPath);
  }else{
    int nCwd;
    if( getcwd(zOut, nOut-1)==0 ){
      return SQLITE_CANTOPEN_BKPT;
    }
    nCwd = (int)strlen(zOut);
    sqlite3_snprintf(nOut-nCwd, &zOut[nCwd], "/%s", zPath);
  }
  return SQLITE_OK;
}

** will fail and SQLITE_BUSY is returned.
**
** The proxy file - a single-byte file used for all advisory file locks
** normally taken on the database file.   This allows for safe sharing
** of the database file for multiple readers and writers on the same
** host (the conch ensures that they all use the same local lock file).
**





** Requesting the lock proxy does not immediately take the conch, it is
** only taken when the first request to lock database file is made.  
** This matches the semantics of the traditional locking behavior, where
** opening a connection to a database file does not take a lock on it.
** The shared lock and an open file descriptor are maintained until 
** the connection to the database is closed. 
**

**       PRAGMA lock_proxy_file=":auto:"
**    
**  SQLITE_PROXY_DEBUG
**
**       Enables the logging of error messages during host id file
**       retrieval and creation
**




**  LOCKPROXYDIR
**
**       Overrides the default directory used for lock proxy files that
**       are named automatically via the ":auto:" setting
**
**  SQLITE_DEFAULT_PROXYDIR_PERMISSIONS
**

*/

/*
** Proxy locking is only available on MacOSX 
*/
#if defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE






/*
** The proxyLockingContext has the path and file structures for the remote 
** and local proxy files in it
*/
typedef struct proxyLockingContext proxyLockingContext;
struct proxyLockingContext {
  unixFile *conchFile;         /* Open conch file */
  char *conchFilePath;         /* Name of the conch file */
  unixFile *lockProxy;         /* Open proxy lock file */
  char *lockProxyPath;         /* Name of the proxy lock file */
  char *dbPath;                /* Name of the open file */
  int conchHeld;               /* 1 if the conch is held, -1 if lockless */
  void *oldLockingContext;     /* Original lockingcontext to restore on close */
  sqlite3_io_methods const *pOldMethod;     /* Original I/O methods for close */
};



/* 





** The proxy lock file path for the database at dbPath is written into lPath, 





** which must point to valid, writable memory large enough for a maxLen length














** file path. 




















*/








































































static int proxyGetLockPath(const char *dbPath, char *lPath, size_t maxLen){
  int len;
  int dbLen;
  int i;

#ifdef LOCKPROXYDIR
  len = strlcpy(lPath, LOCKPROXYDIR, maxLen);
#else
# ifdef _CS_DARWIN_USER_TEMP_DIR
  {
    if( !confstr(_CS_DARWIN_USER_TEMP_DIR, lPath, maxLen) ){
      OSTRACE4("GETLOCKPATH  failed %s errno=%d pid=%d\n",
               lPath, errno, getpid());

      return SQLITE_IOERR_LOCK;




    }




    len = strlcat(lPath, "sqliteplocks", maxLen);    
  }
# else
  len = strlcpy(lPath, "/tmp/", maxLen);
# endif
#endif

  if( lPath[len-1]!='/' ){
    len = strlcat(lPath, "/", maxLen);
  }
  
  /* transform the db path to a unique cache name */
  dbLen = (int)strlen(dbPath);
  for( i=0; i<dbLen && (i+len+7)<maxLen; i++){
    char c = dbPath[i];
    lPath[i+len] = (c=='/')?'_':c;
  }
  lPath[i+len]='\0';
  strlcat(lPath, ":auto:", maxLen);
  OSTRACE3("GETLOCKPATH  proxy lock path=%s pid=%d\n", lPath, getpid());
  return SQLITE_OK;
}

/* 
 ** Creates the lock file and any missing directories in lockPath
 */
static int proxyCreateLockPath(const char *lockPath){
  int i, len;
  char buf[MAXPATHLEN];
  int start = 0;
  
  assert(lockPath!=NULL);
  /* try to create all the intermediate directories */
  len = (int)strlen(lockPath);
  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( mkdir(buf, SQLITE_DEFAULT_PROXYDIR_PERMISSIONS) ){
          int err=errno;
          if( err!=EEXIST ) {
            OSTRACE5("CREATELOCKPATH  FAILED creating %s, "
                     "'%s' proxy lock path=%s pid=%d\n",
                     buf, strerror(err), lockPath, getpid());
            return err;
          }
        }
      }
      start=i+1;
    }
    buf[i] = lockPath[i];
  }
  OSTRACE3("CREATELOCKPATH  proxy lock path=%s pid=%d\n", lockPath, getpid());
  return 0;
}

/*
** Create a new VFS file descriptor (stored in memory obtained from
** sqlite3_malloc) and open the file named "path" in the file descriptor.
**
** The caller is responsible not only for closing the file descriptor
** but also for freeing the memory associated with the file descriptor.
*/
static int proxyCreateUnixFile(
    const char *path,        /* path for the new unixFile */
    unixFile **ppFile,       /* unixFile created and returned by ref */
    int islockfile           /* if non zero missing dirs will be created */
) {
  int fd = -1;
  int dirfd = -1;
  unixFile *pNew;

  int rc = SQLITE_OK;
  int openFlags = O_RDWR | O_CREAT;
  sqlite3_vfs dummyVfs;
  int terrno = 0;
  UnixUnusedFd *pUnused = NULL;

  /* 1. first try to open/create the file
  ** 2. if that fails, and this is a lock file (not-conch), try creating
  ** the parent directories and then try again.
  ** 3. if that fails, try to open the file read-only
  ** otherwise return BUSY (if lock file) or CANTOPEN for the conch file
  */
  pUnused = findReusableFd(path, openFlags);
  if( pUnused ){
    fd = pUnused->fd;
  }else{
    pUnused = sqlite3_malloc(sizeof(*pUnused));
    if( !pUnused ){
      return SQLITE_NOMEM;
    }
  }
  if( fd<0 ){
    fd = open(path, openFlags, SQLITE_DEFAULT_FILE_PERMISSIONS);
    terrno = errno;
    if( fd<0 && errno==ENOENT && islockfile ){
      if( proxyCreateLockPath(path) == SQLITE_OK ){
        fd = open(path, openFlags, SQLITE_DEFAULT_FILE_PERMISSIONS);
      }
    }
  }
  if( fd<0 ){
    openFlags = O_RDONLY;
    fd = open(path, openFlags, SQLITE_DEFAULT_FILE_PERMISSIONS);
    terrno = errno;
  }
  if( fd<0 ){
    if( islockfile ){
      return SQLITE_BUSY;
    }
    switch (terrno) {
      case EACCES:
        return SQLITE_PERM;
      case EIO: 
        return SQLITE_IOERR_LOCK; /* even though it is the conch */
      default:
        return SQLITE_CANTOPEN_BKPT;
    }
  }
  
  pNew = (unixFile *)sqlite3_malloc(sizeof(*pNew));
  if( pNew==NULL ){
    rc = SQLITE_NOMEM;
    goto end_create_proxy;
  }
  memset(pNew, 0, sizeof(unixFile));
  pNew->openFlags = openFlags;












  dummyVfs.pAppData = (void*)&autolockIoFinder;
  pUnused->fd = fd;
  pUnused->flags = openFlags;
  pNew->pUnused = pUnused;
  
  rc = fillInUnixFile(&dummyVfs, fd, dirfd, (sqlite3_file*)pNew, path, 0, 0);
  if( rc==SQLITE_OK ){
    *ppFile = pNew;
    return SQLITE_OK;
  }
end_create_proxy:    
  close(fd); /* silently leak fd if error, we're already in error */
  sqlite3_free(pNew);
  sqlite3_free(pUnused);
  return rc;
}

#ifdef SQLITE_TEST
/* simulate multiple hosts by creating unique hostid file paths */
SQLITE_API int sqlite3_hostid_num = 0;
#endif

#define PROXY_HOSTIDLEN    16  /* conch file host id length */

/* get the host ID via gethostuuid(), pHostID must point to PROXY_HOSTIDLEN 
** bytes of writable memory.
*/
static int proxyGetHostID(unsigned char *pHostID, int *pError){
  struct timespec timeout = {1, 0}; /* 1 sec timeout */
  
  assert(PROXY_HOSTIDLEN == sizeof(uuid_t));
  memset(pHostID, 0, PROXY_HOSTIDLEN);
  if( gethostuuid(pHostID, &timeout) ){
    int err = errno;
    if( pError ){
      *pError = err;
    }
    return SQLITE_IOERR;
  }
#ifdef SQLITE_TEST
  /* simulate multiple hosts by creating unique hostid file paths */
  if( sqlite3_hostid_num != 0){
    pHostID[0] = (char)(pHostID[0] + (char)(sqlite3_hostid_num & 0xFF));
  }
#endif
  
  return SQLITE_OK;
}

/* The conch file contains the header, host id and lock file path
 */
#define PROXY_CONCHVERSION 2   /* 1-byte header, 16-byte host id, path */
#define PROXY_HEADERLEN    1   /* conch file header length */
#define PROXY_PATHINDEX    (PROXY_HEADERLEN+PROXY_HOSTIDLEN)
#define PROXY_MAXCONCHLEN  (PROXY_HEADERLEN+PROXY_HOSTIDLEN+MAXPATHLEN)

/* 
** Takes an open conch file, copies the contents to a new path and then moves 
** it back.  The newly created file's file descriptor is assigned to the
** conch file structure and finally the original conch file descriptor is 
** closed.  Returns zero if successful.
*/
static int proxyBreakConchLock(unixFile *pFile, uuid_t myHostID){
  proxyLockingContext *pCtx = (proxyLockingContext *)pFile->lockingContext; 
  unixFile *conchFile = pCtx->conchFile;
  char tPath[MAXPATHLEN];
  char buf[PROXY_MAXCONCHLEN];
  char *cPath = pCtx->conchFilePath;
  size_t readLen = 0;
  size_t pathLen = 0;
  char errmsg[64] = "";
  int fd = -1;
  int rc = -1;

  /* create a new path by replace the trailing '-conch' with '-break' */
  pathLen = strlcpy(tPath, cPath, MAXPATHLEN);
  if( pathLen>MAXPATHLEN || pathLen<6 || 
     (strlcpy(&tPath[pathLen-5], "break", 6) != 5) ){
    sprintf(errmsg, "path error (len %d)", (int)pathLen);
    goto end_breaklock;
  }
  /* read the conch content */
  readLen = pread(conchFile->h, buf, PROXY_MAXCONCHLEN, 0);
  if( readLen<PROXY_PATHINDEX ){
    sprintf(errmsg, "read error (len %d)", (int)readLen);
    goto end_breaklock;
  }
  /* write it out to the temporary break file */
  fd = open(tPath, (O_RDWR|O_CREAT|O_EXCL), SQLITE_DEFAULT_FILE_PERMISSIONS);
  if( fd<0 ){
    sprintf(errmsg, "create failed (%d)", errno);
    goto end_breaklock;
  }
  if( pwrite(fd, buf, readLen, 0) != readLen ){
    sprintf(errmsg, "write failed (%d)", errno);
    goto end_breaklock;
  }
  if( rename(tPath, cPath) ){
    sprintf(errmsg, "rename failed (%d)", errno);
    goto end_breaklock;
  }
  rc = 0;
  fprintf(stderr, "broke stale lock on %s\n", cPath);
  close(conchFile->h);
  conchFile->h = fd;
  conchFile->openFlags = O_RDWR | O_CREAT;

end_breaklock:
  if( rc ){
    if( fd>=0 ){
      unlink(tPath);
      close(fd);
    }
    fprintf(stderr, "failed to break stale lock on %s, %s\n", cPath, errmsg);
  }
  return rc;
}

/* Take the requested lock on the conch file and break a stale lock if the 
** host id matches.
*/
static int proxyConchLock(unixFile *pFile, uuid_t myHostID, int lockType){
  proxyLockingContext *pCtx = (proxyLockingContext *)pFile->lockingContext; 
  unixFile *conchFile = pCtx->conchFile;
  int rc = SQLITE_OK;
  int nTries = 0;
  struct timespec conchModTime;
  
  do {
    rc = conchFile->pMethod->xLock((sqlite3_file*)conchFile, lockType);
    nTries ++;
    if( rc==SQLITE_BUSY ){
      /* If the lock failed (busy):
       * 1st try: get the mod time of the conch, wait 0.5s and try again. 
       * 2nd try: fail if the mod time changed or host id is different, wait 
       *           10 sec and try again
       * 3rd try: break the lock unless the mod time has changed.
       */
      struct stat buf;
      if( fstat(conchFile->h, &buf) ){
        pFile->lastErrno = errno;
        return SQLITE_IOERR_LOCK;
      }
      
      if( nTries==1 ){
        conchModTime = buf.st_mtimespec;
        usleep(500000); /* wait 0.5 sec and try the lock again*/
        continue;  
      }

      assert( nTries>1 );
      if( conchModTime.tv_sec != buf.st_mtimespec.tv_sec || 
         conchModTime.tv_nsec != buf.st_mtimespec.tv_nsec ){
        return SQLITE_BUSY;
      }
      
      if( nTries==2 ){  
        char tBuf[PROXY_MAXCONCHLEN];
        int len = pread(conchFile->h, tBuf, PROXY_MAXCONCHLEN, 0);
        if( len<0 ){
          pFile->lastErrno = errno;
          return SQLITE_IOERR_LOCK;
        }
        if( len>PROXY_PATHINDEX && tBuf[0]==(char)PROXY_CONCHVERSION){
          /* don't break the lock if the host id doesn't match */
          if( 0!=memcmp(&tBuf[PROXY_HEADERLEN], myHostID, PROXY_HOSTIDLEN) ){
            return SQLITE_BUSY;
          }
        }else{
          /* don't break the lock on short read or a version mismatch */
          return SQLITE_BUSY;
        }
        usleep(10000000); /* wait 10 sec and try the lock again */
        continue; 
      }
      
      assert( nTries==3 );
      if( 0==proxyBreakConchLock(pFile, myHostID) ){
        rc = SQLITE_OK;
        if( lockType==EXCLUSIVE_LOCK ){
          rc = conchFile->pMethod->xLock((sqlite3_file*)conchFile, SHARED_LOCK);          
        }
        if( !rc ){
          rc = conchFile->pMethod->xLock((sqlite3_file*)conchFile, lockType);
        }
      }
    }
  } while( rc==SQLITE_BUSY && nTries<3 );
  
  return rc;
}

/* Takes the conch by taking a shared lock and read the contents conch, if 
** lockPath is non-NULL, the host ID and lock file path must match.  A NULL 
** lockPath means that the lockPath in the conch file will be used if the 
** host IDs match, or a new lock path will be generated automatically 
** and written to the conch file.
*/
static int proxyTakeConch(unixFile *pFile){
  proxyLockingContext *pCtx = (proxyLockingContext *)pFile->lockingContext; 
  
  if( pCtx->conchHeld!=0 ){
    return SQLITE_OK;
  }else{
    unixFile *conchFile = pCtx->conchFile;
    uuid_t myHostID;
    int pError = 0;
    char readBuf[PROXY_MAXCONCHLEN];
    char lockPath[MAXPATHLEN];
    char *tempLockPath = NULL;
    int rc = SQLITE_OK;
    int createConch = 0;
    int hostIdMatch = 0;
    int readLen = 0;
    int tryOldLockPath = 0;
    int forceNewLockPath = 0;
    
    OSTRACE4("TAKECONCH  %d for %s pid=%d\n", conchFile->h,
             (pCtx->lockProxyPath ? pCtx->lockProxyPath : ":auto:"), getpid());





    rc = proxyGetHostID(myHostID, &pError);
    if( (rc&0xff)==SQLITE_IOERR ){
      pFile->lastErrno = pError;
      goto end_takeconch;
    }
    rc = proxyConchLock(pFile, myHostID, SHARED_LOCK);
    if( rc!=SQLITE_OK ){

      goto end_takeconch;
    }

    /* read the existing conch file */
    readLen = seekAndRead((unixFile*)conchFile, 0, readBuf, PROXY_MAXCONCHLEN);
    if( readLen<0 ){
      /* I/O error: lastErrno set by seekAndRead */
      pFile->lastErrno = conchFile->lastErrno;
      rc = SQLITE_IOERR_READ;
      goto end_takeconch;
    }else if( readLen<=(PROXY_HEADERLEN+PROXY_HOSTIDLEN) || 
             readBuf[0]!=(char)PROXY_CONCHVERSION ){
      /* a short read or version format mismatch means we need to create a new 
      ** conch file. 
      */
      createConch = 1;
    }
    /* if the host id matches and the lock path already exists in the conch
    ** we'll try to use the path there, if we can't open that path, we'll 
    ** retry with a new auto-generated path 
    */
    do { /* in case we need to try again for an :auto: named lock file */

      if( !createConch && !forceNewLockPath ){
        hostIdMatch = !memcmp(&readBuf[PROXY_HEADERLEN], myHostID, 
                                  PROXY_HOSTIDLEN);








        /* if the conch has data compare the contents */
        if( !pCtx->lockProxyPath ){
          /* for auto-named local lock file, just check the host ID and we'll
           ** use the local lock file path that's already in there
           */
          if( hostIdMatch ){
            size_t pathLen = (readLen - PROXY_PATHINDEX);
            
            if( pathLen>=MAXPATHLEN ){
              pathLen=MAXPATHLEN-1;
            }
            memcpy(lockPath, &readBuf[PROXY_PATHINDEX], pathLen);
            lockPath[pathLen] = 0;
            tempLockPath = lockPath;
            tryOldLockPath = 1;
            /* create a copy of the lock path if the conch is taken */
            goto end_takeconch;
          }
        }else if( hostIdMatch

               && !strncmp(pCtx->lockProxyPath, &readBuf[PROXY_PATHINDEX],
                           readLen-PROXY_PATHINDEX)
        ){
          /* conch host and lock path match */
          goto end_takeconch; 
        }
      }






      
      /* if the conch isn't writable and doesn't match, we can't take it */
      if( (conchFile->openFlags&O_RDWR) == 0 ){
        rc = SQLITE_BUSY;
        goto end_takeconch;
      }
      
      /* either the conch didn't match or we need to create a new one */
      if( !pCtx->lockProxyPath ){
        proxyGetLockPath(pCtx->dbPath, lockPath, MAXPATHLEN);
        tempLockPath = lockPath;
        /* create a copy of the lock path _only_ if the conch is taken */
      }
      
      /* update conch with host and path (this will fail if other process
      ** has a shared lock already), if the host id matches, use the big
      ** stick.
      */
      futimes(conchFile->h, NULL);
      if( hostIdMatch && !createConch ){
        if( conchFile->pLock && conchFile->pLock->cnt>1 ){
          /* We are trying for an exclusive lock but another thread in this
           ** same process is still holding a shared lock. */
          rc = SQLITE_BUSY;
        } else {          
          rc = proxyConchLock(pFile, myHostID, EXCLUSIVE_LOCK);
        }
      }else{
        rc = conchFile->pMethod->xLock((sqlite3_file*)conchFile, EXCLUSIVE_LOCK);
      }
      if( rc==SQLITE_OK ){
        char writeBuffer[PROXY_MAXCONCHLEN];
        int writeSize = 0;
        
        writeBuffer[0] = (char)PROXY_CONCHVERSION;
        memcpy(&writeBuffer[PROXY_HEADERLEN], myHostID, PROXY_HOSTIDLEN);
        if( pCtx->lockProxyPath!=NULL ){
          strlcpy(&writeBuffer[PROXY_PATHINDEX], pCtx->lockProxyPath, MAXPATHLEN);
        }else{
          strlcpy(&writeBuffer[PROXY_PATHINDEX], tempLockPath, MAXPATHLEN);
        }
        writeSize = PROXY_PATHINDEX + strlen(&writeBuffer[PROXY_PATHINDEX]);
        ftruncate(conchFile->h, writeSize);

        rc = unixWrite((sqlite3_file *)conchFile, writeBuffer, writeSize, 0);
        fsync(conchFile->h);
        /* If we created a new conch file (not just updated the contents of a 
         ** valid conch file), try to match the permissions of the database 
         */
        if( rc==SQLITE_OK && createConch ){
          struct stat buf;
          int err = fstat(pFile->h, &buf);
          if( err==0 ){
            mode_t cmode = buf.st_mode&(S_IRUSR|S_IWUSR | S_IRGRP|S_IWGRP |
                                        S_IROTH|S_IWOTH);
            /* try to match the database file R/W permissions, ignore failure */
#ifndef SQLITE_PROXY_DEBUG
            fchmod(conchFile->h, cmode);
#else
            if( fchmod(conchFile->h, cmode)!=0 ){
              int code = errno;
              fprintf(stderr, "fchmod %o FAILED with %d %s\n",
                      cmode, code, strerror(code));
            } else {
              fprintf(stderr, "fchmod %o SUCCEDED\n",cmode);
            }
          }else{
            int code = errno;
            fprintf(stderr, "STAT FAILED[%d] with %d %s\n", 
                    err, code, strerror(code));
#endif
          }
        }
      }
      conchFile->pMethod->xUnlock((sqlite3_file*)conchFile, SHARED_LOCK);
      
    end_takeconch:
      OSTRACE2("TRANSPROXY: CLOSE  %d\n", pFile->h);
      if( rc==SQLITE_OK && pFile->openFlags ){
        if( pFile->h>=0 ){
#ifdef STRICT_CLOSE_ERROR
          if( close(pFile->h) ){
            pFile->lastErrno = errno;
            return SQLITE_IOERR_CLOSE;
          }
#else
          close(pFile->h); /* silently leak fd if fail */
#endif
        }
        pFile->h = -1;
        int fd = open(pCtx->dbPath, pFile->openFlags,
                      SQLITE_DEFAULT_FILE_PERMISSIONS);
        OSTRACE2("TRANSPROXY: OPEN  %d\n", fd);
        if( fd>=0 ){
          pFile->h = fd;
        }else{
          rc=SQLITE_CANTOPEN_BKPT; /* SQLITE_BUSY? proxyTakeConch called
           during locking */
        }
      }
      if( rc==SQLITE_OK && !pCtx->lockProxy ){
        char *path = tempLockPath ? tempLockPath : pCtx->lockProxyPath;

        rc = proxyCreateUnixFile(path, &pCtx->lockProxy, 1);
        if( rc!=SQLITE_OK && rc!=SQLITE_NOMEM && tryOldLockPath ){
          /* we couldn't create the proxy lock file with the old lock file path
           ** so try again via auto-naming 
           */
          forceNewLockPath = 1;
          tryOldLockPath = 0;
          continue; /* go back to the do {} while start point, try again */
        }
      }
      if( rc==SQLITE_OK ){
        /* Need to make a copy of path if we extracted the value
         ** from the conch file or the path was allocated on the stack
         */
        if( tempLockPath ){
          pCtx->lockProxyPath = sqlite3DbStrDup(0, tempLockPath);
          if( !pCtx->lockProxyPath ){
            rc = SQLITE_NOMEM;
          }
        }
      }
      if( rc==SQLITE_OK ){
        pCtx->conchHeld = 1;
        


        if( pCtx->lockProxy->pMethod == &afpIoMethods ){
          afpLockingContext *afpCtx;
          afpCtx = (afpLockingContext *)pCtx->lockProxy->lockingContext;
          afpCtx->dbPath = pCtx->lockProxyPath;
        }

      } else {
        conchFile->pMethod->xUnlock((sqlite3_file*)conchFile, NO_LOCK);
      }
      OSTRACE3("TAKECONCH  %d %s\n", conchFile->h, rc==SQLITE_OK?"ok":"failed");
      return rc;
    } while (1); /* in case we need to retry the :auto: lock file - we should never get here except via the 'continue' call. */
  }
}

/*
** If pFile holds a lock on a conch file, then release that lock.
*/
static int proxyReleaseConch(unixFile *pFile){
  int rc;                     /* Subroutine return code */
  proxyLockingContext *pCtx;  /* The locking context for the proxy lock */
  unixFile *conchFile;        /* Name of the conch file */

  pCtx = (proxyLockingContext *)pFile->lockingContext;
  conchFile = pCtx->conchFile;
  OSTRACE4("RELEASECONCH  %d for %s pid=%d\n", conchFile->h,
           (pCtx->lockProxyPath ? pCtx->lockProxyPath : ":auto:"), 
           getpid());
  if( pCtx->conchHeld>0 ){
    rc = conchFile->pMethod->xUnlock((sqlite3_file*)conchFile, NO_LOCK);
  }
  pCtx->conchHeld = 0;
  OSTRACE3("RELEASECONCH  %d %s\n", conchFile->h,
           (rc==SQLITE_OK ? "ok" : "failed"));
  return rc;
}

/*
** Given the name of a database file, compute the name of its conch file.

*/
static int proxyGetDbPathForUnixFile(unixFile *pFile, char *dbPath){
#if defined(__APPLE__)
  if( pFile->pMethod == &afpIoMethods ){
    /* afp style keeps a reference to the db path in the filePath field 
    ** of the struct */
    assert( (int)strlen((char*)pFile->lockingContext)<=MAXPATHLEN );
    strlcpy(dbPath, ((afpLockingContext *)pFile->lockingContext)->dbPath, MAXPATHLEN);
  } else
#endif
  if( pFile->pMethod == &dotlockIoMethods ){
    /* dot lock style uses the locking context to store the dot lock
    ** file path */
    int len = strlen((char *)pFile->lockingContext) - strlen(DOTLOCK_SUFFIX);
    memcpy(dbPath, (char *)pFile->lockingContext, len + 1);
  }else{
    /* all other styles use the locking context to store the db file path */
    assert( strlen((char*)pFile->lockingContext)<=MAXPATHLEN );
    strlcpy(dbPath, (char *)pFile->lockingContext, MAXPATHLEN);
  }
  return SQLITE_OK;
}

/*
** Takes an already filled in unix file and alters it so all file locking 
** will be performed on the local proxy lock file.  The following fields

  if( pCtx==0 ){
    return SQLITE_NOMEM;
  }
  memset(pCtx, 0, sizeof(*pCtx));

  rc = proxyCreateConchPathname(dbPath, &pCtx->conchFilePath);
  if( rc==SQLITE_OK ){
    rc = proxyCreateUnixFile(pCtx->conchFilePath, &pCtx->conchFile, 0);
    if( rc==SQLITE_CANTOPEN && ((pFile->openFlags&O_RDWR) == 0) ){
      /* if (a) the open flags are not O_RDWR, (b) the conch isn't there, and
      ** (c) the file system is read-only, then enable no-locking access.
      ** Ugh, since O_RDONLY==0x0000 we test for !O_RDWR since unixOpen asserts
      ** that openFlags will have only one of O_RDONLY or O_RDWR.
      */
      struct statfs fsInfo;
      struct stat conchInfo;
      int goLockless = 0;

      if( stat(pCtx->conchFilePath, &conchInfo) == -1 ) {
        int err = errno;
        if( (err==ENOENT) && (statfs(dbPath, &fsInfo) != -1) ){
          goLockless = (fsInfo.f_flags&MNT_RDONLY) == MNT_RDONLY;
        }
      }
      if( goLockless ){
        pCtx->conchHeld = -1; /* read only FS/ lockless */
        rc = SQLITE_OK;
      }
    }
  }  
  if( rc==SQLITE_OK && lockPath ){
    pCtx->lockProxyPath = sqlite3DbStrDup(0, lockPath);
  }

  if( rc==SQLITE_OK ){
    pCtx->dbPath = sqlite3DbStrDup(0, dbPath);
    if( pCtx->dbPath==NULL ){
      rc = SQLITE_NOMEM;
    }
  }
  if( rc==SQLITE_OK ){
    /* all memory is allocated, proxys are created and assigned, 
    ** switch the locking context and pMethod then return.
    */

    pCtx->oldLockingContext = pFile->lockingContext;
    pFile->lockingContext = pCtx;
    pCtx->pOldMethod = pFile->pMethod;
    pFile->pMethod = &proxyIoMethods;
  }else{
    if( pCtx->conchFile ){ 
      pCtx->conchFile->pMethod->xClose((sqlite3_file *)pCtx->conchFile);

      sqlite3_free(pCtx->conchFile);
    }
    sqlite3_free(pCtx->lockProxyPath);
    sqlite3_free(pCtx->conchFilePath); 
    sqlite3_free(pCtx);
  }
  OSTRACE3("TRANSPROXY  %d %s\n", pFile->h,
           (rc==SQLITE_OK ? "ok" : "failed"));
  return rc;
}

** is set to SQLITE_OK unless an I/O error occurs during lock checking.
*/
static int proxyCheckReservedLock(sqlite3_file *id, int *pResOut) {
  unixFile *pFile = (unixFile*)id;
  int rc = proxyTakeConch(pFile);
  if( rc==SQLITE_OK ){
    proxyLockingContext *pCtx = (proxyLockingContext *)pFile->lockingContext;
    if( pCtx->conchHeld>0 ){
      unixFile *proxy = pCtx->lockProxy;
      return proxy->pMethod->xCheckReservedLock((sqlite3_file*)proxy, pResOut);
    }else{ /* conchHeld < 0 is lockless */
      pResOut=0;
    }
  }
  return rc;
}

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

** routine to lower a locking level.
*/
static int proxyLock(sqlite3_file *id, int locktype) {
  unixFile *pFile = (unixFile*)id;
  int rc = proxyTakeConch(pFile);
  if( rc==SQLITE_OK ){
    proxyLockingContext *pCtx = (proxyLockingContext *)pFile->lockingContext;
    if( pCtx->conchHeld>0 ){
      unixFile *proxy = pCtx->lockProxy;
      rc = proxy->pMethod->xLock((sqlite3_file*)proxy, locktype);
      pFile->locktype = proxy->locktype;
    }else{
      /* conchHeld < 0 is lockless */
    }
  }
  return rc;
}


/*
** Lower the locking level on file descriptor pFile to locktype.  locktype
** 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.
*/
static int proxyUnlock(sqlite3_file *id, int locktype) {
  unixFile *pFile = (unixFile*)id;
  int rc = proxyTakeConch(pFile);
  if( rc==SQLITE_OK ){
    proxyLockingContext *pCtx = (proxyLockingContext *)pFile->lockingContext;
    if( pCtx->conchHeld>0 ){
      unixFile *proxy = pCtx->lockProxy;
      rc = proxy->pMethod->xUnlock((sqlite3_file*)proxy, locktype);
      pFile->locktype = proxy->locktype;
    }else{
      /* conchHeld < 0 is lockless */
    }
  }
  return rc;
}

/*
** Close a file that uses proxy locks.
*/

#if SQLITE_ENABLE_LOCKING_STYLE && (OS_VXWORKS || defined(__APPLE__))
    UNIXVFS("unix",          autolockIoFinder ),
#else
    UNIXVFS("unix",          posixIoFinder ),
#endif
    UNIXVFS("unix-none",     nolockIoFinder ),
    UNIXVFS("unix-dotfile",  dotlockIoFinder ),

#if OS_VXWORKS
    UNIXVFS("unix-namedsem", semIoFinder ),
#endif
#if SQLITE_ENABLE_LOCKING_STYLE
    UNIXVFS("unix-posix",    posixIoFinder ),
#if !OS_VXWORKS
    UNIXVFS("unix-flock",    flockIoFinder ),
#endif
#endif
#if SQLITE_ENABLE_LOCKING_STYLE && defined(__APPLE__)
    UNIXVFS("unix-afp",      afpIoFinder ),
    UNIXVFS("unix-nfs",      nfsIoFinder ),
    UNIXVFS("unix-proxy",    proxyIoFinder ),
#endif
  };
  unsigned int i;          /* Loop counter */

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

  }
  if( h==INVALID_HANDLE_VALUE ){
    free(zConverted);
    if( flags & SQLITE_OPEN_READWRITE ){
      return winOpen(pVfs, zName, id, 
             ((flags|SQLITE_OPEN_READONLY)&~SQLITE_OPEN_READWRITE), pOutFlags);
    }else{
      return SQLITE_CANTOPEN_BKPT;
    }
  }
  if( pOutFlags ){
    if( flags & SQLITE_OPEN_READWRITE ){
      *pOutFlags = SQLITE_OPEN_READWRITE;
    }else{
      *pOutFlags = SQLITE_OPEN_READONLY;

#if SQLITE_OS_WINCE
  if( (flags & (SQLITE_OPEN_READWRITE|SQLITE_OPEN_MAIN_DB)) ==
               (SQLITE_OPEN_READWRITE|SQLITE_OPEN_MAIN_DB)
       && !winceCreateLock(zName, pFile)
  ){
    CloseHandle(h);
    free(zConverted);
    return SQLITE_CANTOPEN_BKPT;
  }
  if( isTemp ){
    pFile->zDeleteOnClose = zConverted;
  }else
#endif
  {
    free(zConverted);

** 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.pcache.xDestroy(pCache->pCache);
    pCache->pCache = 0;
    pCache->pPage1 = 0;
  }
  pCache->szPage = szPage;
}

/*
** Try to obtain a page from the cache.
*/

    ** unreferenced dirty page.
    */
    expensive_assert( pcacheCheckSynced(pCache) );
    for(pPg=pCache->pSynced; 
        pPg && (pPg->nRef || (pPg->flags&PGHDR_NEED_SYNC)); 
        pPg=pPg->pDirtyPrev
    );
    pCache->pSynced = pPg;
    if( !pPg ){
      for(pPg=pCache->pDirtyTail; pPg && pPg->nRef; pPg=pPg->pDirtyPrev);
    }
    if( pPg ){
      int rc;
      rc = pCache->xStress(pCache->pStress, pPg);
      if( rc!=SQLITE_OK && rc!=SQLITE_BUSY ){

    /* If there are dirty pages in the page cache with page numbers greater
    ** than Pager.dbSize, this means sqlite3PagerTruncateImage() was called to
    ** make the file smaller (presumably by auto-vacuum code). Do not write
    ** any such pages to the file.
    **
    ** Also, do not write out any page that has the PGHDR_DONT_WRITE flag
    ** set (set by sqlite3PagerDontWrite()).


    */
    if( pgno<=pPager->dbSize && 0==(pList->flags&PGHDR_DONT_WRITE) ){
      i64 offset = (pgno-1)*(i64)pPager->pageSize;   /* Offset to write */
      char *pData;                                   /* Data to write */    

      /* Encode the database */
      CODEC2(pPager, pList->pData, pgno, 6, return SQLITE_NOMEM, pData);

    if( rc==SQLITE_OK && nPathname+8>pVfs->mxPathname ){
      /* This branch is taken when the journal path required by
      ** the database being opened will be more than pVfs->mxPathname
      ** bytes in length. This means the database cannot be opened,
      ** as it will not be possible to open the journal file or even
      ** check for a hot-journal before reading.
      */
      rc = SQLITE_CANTOPEN_BKPT;
    }
    if( rc!=SQLITE_OK ){
      sqlite3_free(zPathname);
      return rc;
    }
  }

          if( res ){
            int fout = 0;
            int f = SQLITE_OPEN_READWRITE|SQLITE_OPEN_MAIN_JOURNAL;
            assert( !pPager->tempFile );
            rc = sqlite3OsOpen(pVfs, pPager->zJournal, pPager->jfd, f, &fout);
            assert( rc!=SQLITE_OK || isOpen(pPager->jfd) );
            if( rc==SQLITE_OK && fout&SQLITE_OPEN_READONLY ){
              rc = SQLITE_CANTOPEN_BKPT;
              sqlite3OsClose(pPager->jfd);
            }
          }else{
            /* If the journal does not exist, it usually means that some 
            ** other connection managed to get in and roll it back before 
            ** this connection obtained the exclusive lock above. Or, it 
            ** may mean that the pager was in the error-state when this

    }

    rc = sqlite3PagerPagecount(pPager, &nMax);
    if( rc!=SQLITE_OK ){
      goto pager_acquire_err;
    }

    if( MEMDB || nMax<(int)pgno || noContent || !isOpen(pPager->fd) ){
      if( pgno>pPager->mxPgno ){
	rc = SQLITE_FULL;
	goto pager_acquire_err;
      }
      if( noContent ){
        /* Failure to set the bits in the InJournal bit-vectors is benign.
        ** It merely means that we might do some extra work to journal a 
        ** page that does not need to be journaled.  Nevertheless, be sure 
        ** to test the case where a malloc error occurs while trying to set 
        ** a bit in a bit vector.
        */
        sqlite3BeginBenignMalloc();
        if( pgno<=pPager->dbOrigSize ){
          TESTONLY( rc = ) sqlite3BitvecSet(pPager->pInJournal, pgno);
          testcase( rc==SQLITE_NOMEM );
        }
        TESTONLY( rc = ) addToSavepointBitvecs(pPager, pgno);
        testcase( rc==SQLITE_NOMEM );
        sqlite3EndBenignMalloc();


      }
      memset(pPg->pData, 0, pPager->pageSize);
      IOTRACE(("ZERO %p %d\n", pPager, pgno));
    }else{
      assert( pPg->pPager==pPager );
      rc = readDbPage(pPg);
      if( rc!=SQLITE_OK ){
        goto pager_acquire_err;
      }

*/
#ifndef NDEBUG
SQLITE_PRIVATE int sqlite3PagerIswriteable(DbPage *pPg){
  return pPg->flags&PGHDR_DIRTY;
}
#endif


/*
** A call to this routine tells the pager that it is not necessary to
** write the information on page pPg back to the disk, even though
** that page might be marked as dirty.  This happens, for example, when
** the page has been added as a leaf of the freelist and so its
** content no longer matters.
**

    IOTRACE(("CLEAN %p %d\n", pPager, pPg->pgno))
    pPg->flags |= PGHDR_DONT_WRITE;
#ifdef SQLITE_CHECK_PAGES
    pPg->pageHash = pager_pagehash(pPg);
#endif
  }
}


/*
** This routine is called to increment the value of the database file 
** change-counter, stored as a 4-byte big-endian integer starting at 
** byte offset 24 of the pager file.
**
** If the isDirectMode flag is zero, then this is done by calling 

    int ii;            /* Iterator variable */
    int nNew;          /* Number of remaining savepoints after this op. */

    /* Figure out how many savepoints will still be active after this
    ** operation. Store this value in nNew. Then free resources associated 
    ** with any savepoints that are destroyed by this operation.
    */
    nNew = iSavepoint + (( op==SAVEPOINT_RELEASE ) ? 0 : 1);
    for(ii=nNew; ii<pPager->nSavepoint; ii++){
      sqlite3BitvecDestroy(pPager->aSavepoint[ii].pInSavepoint);
    }
    pPager->nSavepoint = nNew;

    /* If this is a release of the outermost savepoint, truncate 
    ** the sub-journal to zero bytes in size. */
    if( op==SAVEPOINT_RELEASE ){
      if( nNew==0 && isOpen(pPager->sjfd) ){
        /* Only truncate if it is an in-memory sub-journal. */
        if( sqlite3IsMemJournal(pPager->sjfd) ){
          rc = sqlite3OsTruncate(pPager->sjfd, 0);
        }
        pPager->nSubRec = 0;
      }
    }
    /* Else this is a rollback operation, playback the specified savepoint.
    ** If this is a temp-file, it is possible that the journal file has
    ** not yet been opened. In this case there have been no changes to
    ** the database file, so the playback operation can be skipped.
    */
    else if( isOpen(pPager->jfd) ){
      PagerSavepoint *pSavepoint = (nNew==0)?0:&pPager->aSavepoint[nNew-1];
      rc = pagerPlaybackSavepoint(pPager, pSavepoint);
      assert(rc!=SQLITE_DONE);
    }
  







  }
  return rc;
}

/*
** Return the full pathname of the database file.
*/

struct BtShared {
  Pager *pPager;        /* The page cache */
  sqlite3 *db;          /* Database connection currently using this Btree */
  BtCursor *pCursor;    /* A list of all open cursors */
  MemPage *pPage1;      /* First page of the database */
  u8 readOnly;          /* True if the underlying file is readonly */
  u8 pageSizeFixed;     /* True if the page size can no longer be changed */
  u8 secureDelete;      /* True if secure_delete is enabled */
#ifndef SQLITE_OMIT_AUTOVACUUM
  u8 autoVacuum;        /* True if auto-vacuum is enabled */
  u8 incrVacuum;        /* True if incr-vacuum is enabled */
#endif
  u16 pageSize;         /* Total number of bytes on a page */
  u16 usableSize;       /* Number of usable bytes on each page */
  u16 maxLocal;         /* Maximum local payload in non-LEAFDATA tables */

  assert( pPage->pBt!=0 );
  assert( sqlite3PagerIswriteable(pPage->pDbPage) );
  assert( start>=pPage->hdrOffset+6+pPage->childPtrSize );
  assert( (start + size)<=pPage->pBt->usableSize );
  assert( sqlite3_mutex_held(pPage->pBt->mutex) );
  assert( size>=0 );   /* Minimum cell size is 4 */

  if( pPage->pBt->secureDelete ){
    /* Overwrite deleted information with zeros when the secure_delete
    ** option is enabled */
    memset(&data[start], 0, size);

  }

  /* Add the space back into the linked list of freeblocks.  Note that
  ** even though the freeblock list was checked by btreeInitPage(),
  ** btreeInitPage() did not detect overlapping cells or
  ** freeblocks that overlapped cells.   Nor does it detect when the
  ** cell content area exceeds the value in the page header.  If these
  ** situations arise, then subsequent insert operations might corrupt

  u16 first;

  assert( sqlite3PagerPagenumber(pPage->pDbPage)==pPage->pgno );
  assert( sqlite3PagerGetExtra(pPage->pDbPage) == (void*)pPage );
  assert( sqlite3PagerGetData(pPage->pDbPage) == data );
  assert( sqlite3PagerIswriteable(pPage->pDbPage) );
  assert( sqlite3_mutex_held(pBt->mutex) );
  if( pBt->secureDelete ){
    memset(&data[hdr], 0, pBt->usableSize - hdr);

  }
  data[hdr] = (char)flags;
  first = hdr + 8 + 4*((flags&PTF_LEAF)==0 ?1:0);
  memset(&data[hdr+1], 0, 4);
  data[hdr+7] = 0;
  put2byte(&data[hdr+5], pBt->usableSize);
  pPage->nFree = pBt->usableSize - first;
  decodeFlags(pPage, flags);

    pBt->db = db;
    sqlite3PagerSetBusyhandler(pBt->pPager, btreeInvokeBusyHandler, pBt);
    p->pBt = pBt;
  
    pBt->pCursor = 0;
    pBt->pPage1 = 0;
    pBt->readOnly = sqlite3PagerIsreadonly(pBt->pPager);
#ifdef SQLITE_SECURE_DELETE
    pBt->secureDelete = 1;
#endif
    pBt->pageSize = get2byte(&zDbHeader[16]);
    if( pBt->pageSize<512 || pBt->pageSize>SQLITE_MAX_PAGE_SIZE
         || ((pBt->pageSize-1)&pBt->pageSize)!=0 ){
      pBt->pageSize = 0;
#ifndef SQLITE_OMIT_AUTOVACUUM
      /* If the magic name ":memory:" will create an in-memory database, then
      ** leave the autoVacuum mode at 0 (do not auto-vacuum), even if

SQLITE_PRIVATE int sqlite3BtreeMaxPageCount(Btree *p, int mxPage){
  int n;
  sqlite3BtreeEnter(p);
  n = sqlite3PagerMaxPageCount(p->pBt->pPager, mxPage);
  sqlite3BtreeLeave(p);
  return n;
}

/*
** Set the secureDelete flag if newFlag is 0 or 1.  If newFlag is -1,
** then make no changes.  Always return the value of the secureDelete
** setting after the change.
*/
SQLITE_PRIVATE int sqlite3BtreeSecureDelete(Btree *p, int newFlag){
  int b;
  if( p==0 ) return 0;
  sqlite3BtreeEnter(p);
  if( newFlag>=0 ){
    p->pBt->secureDelete = (newFlag!=0) ? 1 : 0;
  } 
  b = p->pBt->secureDelete;
  sqlite3BtreeLeave(p);
  return b;
}
#endif /* !defined(SQLITE_OMIT_PAGER_PRAGMAS) || !defined(SQLITE_OMIT_VACUUM) */

/*
** Change the 'auto-vacuum' property of the database. If the 'autoVacuum'
** parameter is non-zero, then auto-vacuum mode is enabled. If zero, it
** is disabled. The default value for the auto-vacuum property is 
** determined by the SQLITE_DEFAULT_AUTOVACUUM macro.

  /* Increment the free page count on pPage1 */
  rc = sqlite3PagerWrite(pPage1->pDbPage);
  if( rc ) goto freepage_out;
  nFree = get4byte(&pPage1->aData[36]);
  put4byte(&pPage1->aData[36], nFree+1);

  if( pBt->secureDelete ){
    /* If the secure_delete option is enabled, then
    ** always fully overwrite deleted information with zeros.
    */
    if( (!pPage && ((rc = btreeGetPage(pBt, iPage, &pPage, 0))!=0) )
     ||            ((rc = sqlite3PagerWrite(pPage->pDbPage))!=0)
    ){
      goto freepage_out;
    }
    memset(pPage->aData, 0, pPage->pBt->pageSize);

  }

  /* If the database supports auto-vacuum, write an entry in the pointer-map
  ** to indicate that the page is free.
  */
  if( ISAUTOVACUUM ){
    ptrmapPut(pBt, iPage, PTRMAP_FREEPAGE, 0, &rc);
    if( rc ) goto freepage_out;

      ** to 3.6.0 or later) we should consider fixing the conditional above
      ** to read "usableSize/4-2" instead of "usableSize/4-8".
      */
      rc = sqlite3PagerWrite(pTrunk->pDbPage);
      if( rc==SQLITE_OK ){
        put4byte(&pTrunk->aData[4], nLeaf+1);
        put4byte(&pTrunk->aData[8+nLeaf*4], iPage);

        if( pPage && !pBt->secureDelete ){
          sqlite3PagerDontWrite(pPage->pDbPage);
        }

        rc = btreeSetHasContent(pBt, iPage);
      }
      TRACE(("FREE-PAGE: %d leaf on trunk page %d\n",pPage->pgno,pTrunk->pgno));
      goto freepage_out;
    }
  }

      ** file the database must be corrupt. */
      return SQLITE_CORRUPT_BKPT;
    }
    if( nOvfl ){
      rc = getOverflowPage(pBt, ovflPgno, &pOvfl, &iNext);
      if( rc ) return rc;
    }

    if( (pOvfl || (pOvfl = btreePageLookup(pBt, ovflPgno)))
     && sqlite3PagerPageRefcount(pOvfl->pDbPage)!=1
    ){
      /* There is no reason any cursor should have an outstanding reference 
      ** to an overflow page belonging to a cell that is being deleted/updated.
      ** So if there exists more than one reference to this page, then it 
      ** must not really be an overflow page and the database must be corrupt. 
      ** It is helpful to detect this before calling freePage2(), as 
      ** freePage2() may zero the page contents if secure-delete mode is
      ** enabled. If this 'overflow' page happens to be a page that the
      ** caller is iterating through or using in some other way, this
      ** can be problematic.
      */
      rc = SQLITE_CORRUPT_BKPT;
    }else{
      rc = freePage2(pBt, pOvfl, ovflPgno);
    }

    if( pOvfl ){
      sqlite3PagerUnref(pOvfl->pDbPage);
    }
    if( rc ) return rc;
    ovflPgno = iNext;
  }
  return SQLITE_OK;

  int i,            /* New cell becomes the i-th cell of the page */
  u8 *pCell,        /* Content of the new cell */
  int sz,           /* Bytes of content in pCell */
  u8 *pTemp,        /* Temp storage space for pCell, if needed */
  Pgno iChild,      /* If non-zero, replace first 4 bytes with this value */
  int *pRC          /* Read and write return code from here */
){
  int idx = 0;      /* Where to write new cell content in data[] */
  int j;            /* Loop counter */
  int end;          /* First byte past the last cell pointer in data[] */
  int ins;          /* Index in data[] where new cell pointer is inserted */
  int cellOffset;   /* Address of first cell pointer in data[] */
  u8 *data;         /* The content of the whole page */
  u8 *ptr;          /* Used for moving information around in data[] */

      ** later on.  
      **
      ** Unless SQLite is compiled in secure-delete mode. In this case,
      ** the dropCell() routine will overwrite the entire cell with zeroes.
      ** In this case, temporarily copy the cell into the aOvflSpace[]
      ** buffer. It will be copied out again as soon as the aSpace[] buffer
      ** is allocated.  */
      if( pBt->secureDelete ){
        int iOff = apDiv[i] - pParent->aData;
        if( (iOff+szNew[i])>pBt->usableSize ){
          rc = SQLITE_CORRUPT_BKPT;
          memset(apOld, 0, (i+1)*sizeof(MemPage*));
          goto balance_cleanup;
        }else{
          memcpy(&aOvflSpace[iOff], apDiv[i], szNew[i]);
          apDiv[i] = &aOvflSpace[apDiv[i]-pParent->aData];

        }
      }
      dropCell(pParent, i+nxDiv-pParent->nOverflow, szNew[i], &rc);
    }
  }

  /* Make nMaxCells a multiple of 4 in order to preserve 8-byte
  ** alignment */
  nMaxCells = (nMaxCells + 3)&~3;

    subtotal += szCell[i] + 2;
    if( subtotal > usableSpace ){
      szNew[k] = subtotal - szCell[i];
      cntNew[k] = i;
      if( leafData ){ i--; }
      subtotal = 0;
      k++;
      if( k>NB+1 ){ rc = SQLITE_CORRUPT_BKPT; goto balance_cleanup; }
    }
  }
  szNew[k] = subtotal;
  cntNew[k] = nCell;
  k++;

  /*

    nOld>=3 ? apOld[2]->pgno : 0
  ));

  /*
  ** Allocate k new pages.  Reuse old pages where possible.
  */
  if( apOld[0]->pgno<=1 ){
    rc = SQLITE_CORRUPT_BKPT;
    goto balance_cleanup;
  }
  pageFlags = apOld[0]->aData[0];
  for(i=0; i<k; i++){
    MemPage *pNew;
    if( i<nOld ){
      pNew = apNew[i] = apOld[i];

**      7.  Verify that the depth of all children is the same.
**      8.  Make sure this page is at least 33% full or else it is
**          the root of the tree.
*/
static int checkTreePage(
  IntegrityCk *pCheck,  /* Context for the sanity check */
  int iPage,            /* Page number of the page to check */
  char *zParentContext, /* Parent context */
  i64 *pnParentMinKey, 
  i64 *pnParentMaxKey
){
  MemPage *pPage;
  int i, rc, depth, d2, pgno, cnt;
  int hdr, cellStart;
  int nCell;
  u8 *data;
  BtShared *pBt;
  int usableSize;
  char zContext[100];
  char *hit = 0;
  i64 nMinKey = 0;
  i64 nMaxKey = 0;

  sqlite3_snprintf(sizeof(zContext), zContext, "Page %d: ", iPage);

  /* Check that the page exists
  */
  pBt = pCheck->pBt;
  usableSize = pBt->usableSize;

    */
    sqlite3_snprintf(sizeof(zContext), zContext,
             "On tree page %d cell %d: ", iPage, i);
    pCell = findCell(pPage,i);
    btreeParseCellPtr(pPage, pCell, &info);
    sz = info.nData;
    if( !pPage->intKey ) sz += (int)info.nKey;
    /* For intKey pages, check that the keys are in order.
    */
    else if( i==0 ) nMinKey = nMaxKey = info.nKey;
    else{
      if( info.nKey <= nMaxKey ){
        checkAppendMsg(pCheck, zContext, 
            "Rowid %lld out of order (previous was %lld)", info.nKey, nMaxKey);
      }
      nMaxKey = info.nKey;
    }
    assert( sz==info.nPayload );
    if( (sz>info.nLocal) 
     && (&pCell[info.iOverflow]<=&pPage->aData[pBt->usableSize])
    ){
      int nPage = (sz - info.nLocal + usableSize - 5)/(usableSize - 4);
      Pgno pgnoOvfl = get4byte(&pCell[info.iOverflow]);
#ifndef SQLITE_OMIT_AUTOVACUUM

    if( !pPage->leaf ){
      pgno = get4byte(pCell);
#ifndef SQLITE_OMIT_AUTOVACUUM
      if( pBt->autoVacuum ){
        checkPtrmap(pCheck, pgno, PTRMAP_BTREE, iPage, zContext);
      }
#endif
      d2 = checkTreePage(pCheck, pgno, zContext, &nMinKey, i==0 ? NULL : &nMaxKey);
      if( i>0 && d2!=depth ){
        checkAppendMsg(pCheck, zContext, "Child page depth differs");
      }
      depth = d2;
    }
  }

  if( !pPage->leaf ){
    pgno = get4byte(&pPage->aData[pPage->hdrOffset+8]);
    sqlite3_snprintf(sizeof(zContext), zContext, 
                     "On page %d at right child: ", iPage);
#ifndef SQLITE_OMIT_AUTOVACUUM
    if( pBt->autoVacuum ){
      checkPtrmap(pCheck, pgno, PTRMAP_BTREE, iPage, zContext);
    }
#endif
    checkTreePage(pCheck, pgno, zContext, NULL, !pPage->nCell ? NULL : &nMaxKey);
  }
 
  /* For intKey leaf pages, check that the min/max keys are in order
  ** with any left/parent/right pages.
  */
  if( pPage->leaf && pPage->intKey ){
    /* if we are a left child page */
    if( pnParentMinKey ){
      /* if we are the left most child page */
      if( !pnParentMaxKey ){
        if( nMaxKey > *pnParentMinKey ){
          checkAppendMsg(pCheck, zContext, 
              "Rowid %lld out of order (max larger than parent min of %lld)",
              nMaxKey, *pnParentMinKey);
        }
      }else{
        if( nMinKey <= *pnParentMinKey ){
          checkAppendMsg(pCheck, zContext, 
              "Rowid %lld out of order (min less than parent min of %lld)",
              nMinKey, *pnParentMinKey);
        }
        if( nMaxKey > *pnParentMaxKey ){
          checkAppendMsg(pCheck, zContext, 
              "Rowid %lld out of order (max larger than parent max of %lld)",
              nMaxKey, *pnParentMaxKey);
        }
        *pnParentMinKey = nMaxKey;
      }
    /* else if we're a right child page */
    } else if( pnParentMaxKey ){
      if( nMinKey <= *pnParentMaxKey ){
        checkAppendMsg(pCheck, zContext, 
            "Rowid %lld out of order (min less than parent max of %lld)",
            nMinKey, *pnParentMaxKey);
      }
    }
  }

  /* Check for complete coverage of the page
  */
  data = pPage->aData;
  hdr = pPage->hdrOffset;
  hit = sqlite3PageMalloc( pBt->pageSize );
  if( hit==0 ){
    pCheck->mallocFailed = 1;

      u16 size = 1024;
      int j;
      if( pc<=usableSize-4 ){
        size = cellSizePtr(pPage, &data[pc]);
      }
      if( (pc+size-1)>=usableSize ){
        checkAppendMsg(pCheck, 0, 
            "Corruption detected in cell %d on page %d",i,iPage);
      }else{
        for(j=pc+size-1; j>=pc; j--) hit[j]++;
      }
    }
    i = get2byte(&data[hdr+1]);
    while( i>0 ){
      int size, j;

  for(i=0; (int)i<nRoot && sCheck.mxErr; i++){
    if( aRoot[i]==0 ) continue;
#ifndef SQLITE_OMIT_AUTOVACUUM
    if( pBt->autoVacuum && aRoot[i]>1 ){
      checkPtrmap(&sCheck, aRoot[i], PTRMAP_ROOTPAGE, 0, 0);
    }
#endif
    checkTreePage(&sCheck, aRoot[i], "List of tree roots: ", NULL, NULL);
  }

  /* Make sure every page in the file is referenced
  */
  for(i=1; i<=sCheck.nPage && sCheck.mxErr; i++){
#ifdef SQLITE_OMIT_AUTOVACUUM
    if( sCheck.anRef[i]==0 ){

    pParse = sqlite3StackAllocZero(pErrorDb, sizeof(*pParse));
    if( pParse==0 ){
      sqlite3Error(pErrorDb, SQLITE_NOMEM, "out of memory");
      rc = SQLITE_NOMEM;
    }else{
      pParse->db = pDb;
      if( sqlite3OpenTempDatabase(pParse) ){

        sqlite3Error(pErrorDb, pParse->rc, "%s", pParse->zErrMsg);
        rc = SQLITE_ERROR;
      }
      sqlite3DbFree(pErrorDb, pParse->zErrMsg);
      sqlite3StackFree(pErrorDb, pParse);
    }
    if( rc ){
      return 0;
    }
  }

** there are reports that windows throws an expection
** if the floating point value is out of range. (See ticket #2880.)
** Because we do not completely understand the problem, we will
** take the conservative approach and always do range tests
** before attempting the conversion.
*/
static i64 doubleToInt64(double r){
#ifdef SQLITE_OMIT_FLOATING_POINT
  /* When floating-point is omitted, double and int64 are the same thing */
  return r;
#else
  /*
  ** Many compilers we encounter do not define constants for the
  ** minimum and maximum 64-bit integers, or they define them
  ** inconsistently.  And many do not understand the "LL" notation.
  ** So we define our own static constants here using nothing
  ** larger than a 32-bit integer constant.
  */

    ** a very large positive number to an integer results in a very large
    ** negative integer.  This makes no sense, but it is what x86 hardware
    ** does so for compatibility we will do the same in software. */
    return minInt;
  }else{
    return (i64)r;
  }
#endif
}

/*
** Return some kind of integer value which is the best we can do
** at representing the value that *pMem describes as an integer.
** If pMem is an integer, then the value is exact.  If pMem is
** a floating-point then the value returned is the integer part.

  MemSetTypeFlag(pMem, MEM_Real);
  return SQLITE_OK;
}

/*
** Convert pMem so that it has types MEM_Real or MEM_Int or both.
** Invalidate any prior representations.
**
** Every effort is made to force the conversion, even if the input
** is a string that does not look completely like a number.  Convert
** as much of the string as we can and ignore the rest.
*/
SQLITE_PRIVATE int sqlite3VdbeMemNumerify(Mem *pMem){
  int rc;

  assert( (pMem->flags & (MEM_Int|MEM_Real|MEM_Null))==0 );
  assert( (pMem->flags & (MEM_Blob|MEM_Str))!=0 );
  assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
  rc = sqlite3VdbeChangeEncoding(pMem, SQLITE_UTF8);


  if( rc ) return rc;
  rc = sqlite3VdbeMemNulTerminate(pMem);
  if( rc ) return rc;
  if( sqlite3Atoi64(pMem->z, &pMem->u.i) ){
    MemSetTypeFlag(pMem, MEM_Int);
  }else{
    pMem->r = sqlite3VdbeRealValue(pMem);
    MemSetTypeFlag(pMem, MEM_Real);
    sqlite3VdbeIntegerAffinity(pMem);
  }
  return SQLITE_OK;
}

/*
** Delete any previous value and set the value stored in *pMem to NULL.
*/

SQLITE_PRIVATE void sqlite3VdbeMemSetInt64(Mem *pMem, i64 val){
  sqlite3VdbeMemRelease(pMem);
  pMem->u.i = val;
  pMem->flags = MEM_Int;
  pMem->type = SQLITE_INTEGER;
}

#ifndef SQLITE_OMIT_FLOATING_POINT
/*
** Delete any previous value and set the value stored in *pMem to val,
** manifest type REAL.
*/
SQLITE_PRIVATE void sqlite3VdbeMemSetDouble(Mem *pMem, double val){
  if( sqlite3IsNaN(val) ){
    sqlite3VdbeMemSetNull(pMem);
  }else{
    sqlite3VdbeMemRelease(pMem);
    pMem->r = val;
    pMem->flags = MEM_Real;
    pMem->type = SQLITE_FLOAT;
  }
}
#endif

/*
** Delete any previous value and set the value of pMem to be an
** empty boolean index.
*/
SQLITE_PRIVATE void sqlite3VdbeMemSetRowSet(Mem *pMem){
  sqlite3 *db = pMem->db;

}

/*
** Return the SQL associated with a prepared statement
*/
SQLITE_API const char *sqlite3_sql(sqlite3_stmt *pStmt){
  Vdbe *p = (Vdbe *)pStmt;
  return (p && p->isPrepareV2) ? p->zSql : 0;
}

/*
** Swap all content between two VDBE structures.
*/
SQLITE_PRIVATE void sqlite3VdbeSwap(Vdbe *pA, Vdbe *pB){
  Vdbe tmp, *pTmp;

  int j = -1-x;
  assert( p->magic==VDBE_MAGIC_INIT );
  assert( j>=0 && j<p->nLabel );
  if( p->aLabel ){
    p->aLabel[j] = p->nOp;
  }
}

/*
** Mark the VDBE as one that can only be run one time.
*/
SQLITE_PRIVATE void sqlite3VdbeRunOnlyOnce(Vdbe *p){
  p->runOnlyOnce = 1;
}

#ifdef SQLITE_DEBUG /* sqlite3AssertMayAbort() logic */

/*
** The following type and function are used to iterate through all opcodes
** in a Vdbe main program and each of the sub-programs (triggers) it may 
** invoke directly or indirectly. It should be used as follows:

  sqlite3 *db = p->db;                 /* The database connection */
  int i;                               /* Loop counter */
  int rc = SQLITE_OK;                  /* Return code */
  Mem *pMem = p->pResultSet = &p->aMem[1];  /* First Mem of result set */

  assert( p->explain );
  assert( p->magic==VDBE_MAGIC_RUN );

  assert( p->rc==SQLITE_OK || p->rc==SQLITE_BUSY || p->rc==SQLITE_NOMEM );

  /* Even though this opcode does not use dynamic strings for
  ** the result, result columns may become dynamic if the user calls
  ** sqlite3_column_text16(), causing a translation to UTF-16 encoding.
  */
  releaseMemArray(pMem, 8);

    sqlite3BtreeCloseCursor(pCx->pCursor);
  }
#ifndef SQLITE_OMIT_VIRTUALTABLE
  if( pCx->pVtabCursor ){
    sqlite3_vtab_cursor *pVtabCursor = pCx->pVtabCursor;
    const sqlite3_module *pModule = pCx->pModule;
    p->inVtabMethod = 1;

    pModule->xClose(pVtabCursor);

    p->inVtabMethod = 0;
  }
#endif
}

/*
** Copy the values stored in the VdbeFrame structure to its Vdbe. This

      needXcommit = 1;
      if( i!=1 ) nTrans++;
    }
  }

  /* If there are any write-transactions at all, invoke the commit hook */
  if( needXcommit && db->xCommitCallback ){

    rc = db->xCommitCallback(db->pCommitArg);

    if( rc ){
      return SQLITE_CONSTRAINT;
    }
  }

  /* The simple case - no more than one database file (not counting the
  ** TEMP database) has a transaction active.   There is no need for the

  sqlite3 *db;
  db = p->db;

  /* If the VM did not run to completion or if it encountered an
  ** error, then it might not have been halted properly.  So halt
  ** it now.
  */

  sqlite3VdbeHalt(p);


  /* If the VDBE has be run even partially, then transfer the error code
  ** and error message from the VDBE into the main database structure.  But
  ** if the VDBE has just been set to run but has not actually executed any
  ** instructions yet, leave the main database error information unchanged.
  */
  if( p->pc>=0 ){
    if( p->zErrMsg ){
      sqlite3BeginBenignMalloc();
      sqlite3ValueSetStr(db->pErr,-1,p->zErrMsg,SQLITE_UTF8,SQLITE_TRANSIENT);
      sqlite3EndBenignMalloc();
      db->errCode = p->rc;
      sqlite3DbFree(db, p->zErrMsg);
      p->zErrMsg = 0;
    }else if( p->rc ){
      sqlite3Error(db, p->rc, 0);
    }else{
      sqlite3Error(db, SQLITE_OK, 0);
    }
    if( p->runOnlyOnce ) p->expired = 1;
  }else if( p->rc && p->expired ){
    /* The expired flag was set on the VDBE before the first call
    ** to sqlite3_step(). For consistency (since sqlite3_step() was
    ** called), set the database error in this case as well.
    */
    sqlite3Error(db, p->rc, 0);
    sqlite3ValueSetStr(db->pErr, -1, p->zErrMsg, SQLITE_UTF8, SQLITE_TRANSIENT);

  releaseMemArray(p->aColName, p->nResColumn*COLNAME_N);
  vdbeFreeOpArray(db, p->aOp, p->nOp);
  sqlite3DbFree(db, p->aLabel);
  sqlite3DbFree(db, p->aColName);
  sqlite3DbFree(db, p->zSql);
  p->magic = VDBE_MAGIC_DEAD;
  sqlite3DbFree(db, p->pFree);
  p->db = 0;
  sqlite3DbFree(db, p);
}

/*
** Make sure the cursor p is ready to read or write the row to which it
** was last positioned.  Return an error code if an OOM fault or I/O error
** prevents us from positioning the cursor to its correct position.

  assert( sqlite3BtreeCursorIsValid(pCur) );
  rc = sqlite3BtreeKeySize(pCur, &nCellKey);
  assert( rc==SQLITE_OK );    /* pCur is always valid so KeySize cannot fail */
  /* nCellKey will always be between 0 and 0xffffffff because of the say
  ** that btreeParseCellPtr() and sqlite3GetVarint32() are implemented */
  if( nCellKey<=0 || nCellKey>0x7fffffff ){
    *res = 0;
    return SQLITE_CORRUPT_BKPT;
  }
  memset(&m, 0, sizeof(m));
  rc = sqlite3VdbeMemFromBtree(pC->pCursor, 0, (int)nCellKey, 1, &m);
  if( rc ){
    return rc;
  }
  assert( pUnpacked->flags & UNPACKED_IGNORE_ROWID );

** added or changed.
*/
SQLITE_API int sqlite3_expired(sqlite3_stmt *pStmt){
  Vdbe *p = (Vdbe*)pStmt;
  return p==0 || p->expired;
}
#endif

/*
** Check on a Vdbe to make sure it has not been finalized.  Log
** an error and return true if it has been finalized (or is otherwise
** invalid).  Return false if it is ok.
*/
static int vdbeSafety(Vdbe *p){
  if( p->db==0 ){
    sqlite3_log(SQLITE_MISUSE, "API called with finalized prepared statement");
    return 1;
  }else{
    return 0;
  }
}
static int vdbeSafetyNotNull(Vdbe *p){
  if( p==0 ){
    sqlite3_log(SQLITE_MISUSE, "API called with NULL prepared statement");
    return 1;
  }else{
    return vdbeSafety(p);
  }
}

/*
** The following routine destroys a virtual machine that is created by
** the sqlite3_compile() routine. The integer returned is an SQLITE_
** success/failure code that describes the result of executing the virtual
** machine.
**
** This routine sets the error code and string returned by
** sqlite3_errcode(), sqlite3_errmsg() and sqlite3_errmsg16().
*/
SQLITE_API int sqlite3_finalize(sqlite3_stmt *pStmt){
  int rc;
  if( pStmt==0 ){
    rc = SQLITE_OK;
  }else{
    Vdbe *v = (Vdbe*)pStmt;
    sqlite3 *db = v->db;
#if SQLITE_THREADSAFE
    sqlite3_mutex *mutex;
#endif
    if( vdbeSafety(v) ) return SQLITE_MISUSE_BKPT;
#if SQLITE_THREADSAFE
    mutex = v->db->mutex;
#endif
    sqlite3_mutex_enter(mutex);
    rc = sqlite3VdbeFinalize(v);
    rc = sqlite3ApiExit(db, rc);
    sqlite3_mutex_leave(mutex);
  }
  return rc;

*/
static int sqlite3Step(Vdbe *p){
  sqlite3 *db;
  int rc;

  assert(p);
  if( p->magic!=VDBE_MAGIC_RUN ){
    sqlite3_log(SQLITE_MISUSE, 
          "attempt to step a halted statement: [%s]", p->zSql);
    return SQLITE_MISUSE_BKPT;
  }

  /* Check that malloc() has not failed. If it has, return early. */
  db = p->db;
  if( db->mallocFailed ){
    p->rc = SQLITE_NOMEM;
    return SQLITE_NOMEM;
  }

  if( p->pc<=0 && p->expired ){

    p->rc = SQLITE_SCHEMA;

    rc = SQLITE_ERROR;
    goto end_of_step;
  }




  if( p->pc<0 ){
    /* If there are no other statements currently running, then
    ** reset the interrupt flag.  This prevents a call to sqlite3_interrupt
    ** from interrupting a statement that has not yet started.
    */
    if( db->activeVdbeCnt==0 ){
      db->u1.isInterrupted = 0;

    rc = sqlite3VdbeList(p);
  }else
#endif /* SQLITE_OMIT_EXPLAIN */
  {
    rc = sqlite3VdbeExec(p);
  }





#ifndef SQLITE_OMIT_TRACE
  /* Invoke the profile callback if there is one
  */
  if( rc!=SQLITE_ROW && db->xProfile && !db->init.busy && p->zSql ){
    double rNow;
    u64 elapseTime;

/*
** This is the top-level implementation of sqlite3_step().  Call
** sqlite3Step() to do most of the work.  If a schema error occurs,
** call sqlite3Reprepare() and try again.
*/
SQLITE_API int sqlite3_step(sqlite3_stmt *pStmt){
  int rc = SQLITE_OK;      /* Result from sqlite3Step() */

  int rc2 = SQLITE_OK;     /* Result from sqlite3Reprepare() */
  Vdbe *v = (Vdbe*)pStmt;  /* the prepared statement */
  int cnt = 0;             /* Counter to prevent infinite loop of reprepares */
  sqlite3 *db;             /* The database connection */

  if( vdbeSafetyNotNull(v) ){
    return SQLITE_MISUSE_BKPT;
  }
  db = v->db;
  sqlite3_mutex_enter(db->mutex);
  while( (rc = sqlite3Step(v))==SQLITE_SCHEMA
         && cnt++ < 5
         && (rc2 = rc = sqlite3Reprepare(v))==SQLITE_OK ){
    sqlite3_reset(pStmt);
    v->expired = 0;
  }
  if( rc2!=SQLITE_OK && ALWAYS(v->isPrepareV2) && ALWAYS(db->pErr) ){
    /* This case occurs after failing to recompile an sql statement. 
    ** The error message from the SQL compiler has already been loaded 
    ** into the database handle. This block copies the error message 
    ** from the database handle into the statement and sets the statement
    ** program counter to 0 to ensure that when the statement is 
    ** finalized or reset the parser error message is available via
    ** sqlite3_errmsg() and sqlite3_errcode().
    */
    const char *zErr = (const char *)sqlite3_value_text(db->pErr); 
    sqlite3DbFree(db, v->zErrMsg);
    if( !db->mallocFailed ){
      v->zErrMsg = sqlite3DbStrDup(db, zErr);
      v->rc = rc2;
    } else {
      v->zErrMsg = 0;
      v->rc = rc = SQLITE_NOMEM;
    }
  }
  rc = sqlite3ApiExit(db, rc);
  sqlite3_mutex_leave(db->mutex);

  return rc;
}

/*
** Extract the user data from a sqlite3_context structure and return a
** pointer to it.
*/

** the mutex is released if any kind of error occurs.
**
** The error code stored in database p->db is overwritten with the return
** value in any case.
*/
static int vdbeUnbind(Vdbe *p, int i){
  Mem *pVar;
  if( vdbeSafetyNotNull(p) ){
    return SQLITE_MISUSE_BKPT;
  }
  sqlite3_mutex_enter(p->db->mutex);
  if( p->magic!=VDBE_MAGIC_RUN || p->pc>=0 ){
    sqlite3Error(p->db, SQLITE_MISUSE, 0);
    sqlite3_mutex_leave(p->db->mutex);
    sqlite3_log(SQLITE_MISUSE, 
        "bind on a busy prepared statement: [%s]", p->zSql);
    return SQLITE_MISUSE_BKPT;
  }
  if( i<1 || i>p->nVar ){
    sqlite3Error(p->db, SQLITE_RANGE, 0);
    sqlite3_mutex_leave(p->db->mutex);
    return SQLITE_RANGE;
  }
  i--;

**
** After this routine has finished, sqlite3VdbeFinalize() should be
** used to clean up the mess that was left behind.
*/
SQLITE_PRIVATE int sqlite3VdbeExec(
  Vdbe *p                    /* The VDBE */
){
  int pc=0;                  /* The program counter */
  Op *aOp = p->aOp;          /* Copy of p->aOp */
  Op *pOp;                   /* Current operation */
  int rc = SQLITE_OK;        /* Value to return */
  sqlite3 *db = p->db;       /* The database */
  u8 resetSchemaOnFault = 0; /* Reset schema after an error if true */
  u8 encoding = ENC(db);     /* The database encoding */
#ifndef SQLITE_OMIT_PROGRESS_CALLBACK

      int i;             /* Loop counter */
      char *zData;       /* Part of the record being decoded */
      Mem *pDest;        /* Where to write the extracted value */
      Mem sMem;          /* For storing the record being decoded */
      u8 *zIdx;          /* Index into header */
      u8 *zEndHdr;       /* Pointer to first byte after the header */
      u32 offset;        /* Offset into the data */
      u32 szField;       /* Number of bytes in the content of a field */
      int szHdr;         /* Size of the header size field at start of record */
      int avail;         /* Number of bytes of available data */
      Mem *pReg;         /* PseudoTable input register */
    } am;
    struct OP_Affinity_stack_vars {
      const char *zAffinity;   /* The affinity to be applied */
      char cAff;               /* A single character of affinity */

      char *zTrace;
    } cm;
  } u;
  /* End automatically generated code
  ********************************************************************/

  assert( p->magic==VDBE_MAGIC_RUN );  /* sqlite3_step() verifies this */

  sqlite3VdbeMutexArrayEnter(p);
  if( p->rc==SQLITE_NOMEM ){
    /* This happens if a malloc() inside a call to sqlite3_column_text() or
    ** sqlite3_column_text16() failed.  */
    goto no_mem;
  }
  assert( p->rc==SQLITE_OK || p->rc==SQLITE_BUSY );

    ** sqlite3VdbeExec() or since last time the progress callback was called).
    ** If the progress callback returns non-zero, exit the virtual machine with
    ** a return code SQLITE_ABORT.
    */
    if( checkProgress ){
      if( db->nProgressOps==nProgressOps ){
        int prc;

        prc = db->xProgress(db->pProgressArg);

        if( prc!=0 ){
          rc = SQLITE_INTERRUPT;
          goto vdbe_error_halt;
        }
        nProgressOps = 0;
      }
      nProgressOps++;

    break;
  }

  p->rc = pOp->p1;
  p->errorAction = (u8)pOp->p2;
  p->pc = pc;
  if( pOp->p4.z ){
    assert( p->rc!=SQLITE_OK );
    sqlite3SetString(&p->zErrMsg, db, "%s", pOp->p4.z);
    testcase( sqlite3GlobalConfig.xLog!=0 );
    sqlite3_log(pOp->p1, "abort at %d in [%s]: %s", pc, p->zSql, pOp->p4.z);
  }else if( p->rc ){
    testcase( sqlite3GlobalConfig.xLog!=0 );
    sqlite3_log(pOp->p1, "constraint failed at %d in [%s]", pc, p->zSql);
  }
  rc = sqlite3VdbeHalt(p);
  assert( rc==SQLITE_BUSY || rc==SQLITE_OK || rc==SQLITE_ERROR );
  if( rc==SQLITE_BUSY ){
    p->rc = rc = SQLITE_BUSY;
  }else{
    assert( rc==SQLITE_OK || p->rc==SQLITE_CONSTRAINT );

*/
case OP_Int64: {           /* out2-prerelease */
  assert( pOp->p4.pI64!=0 );
  pOut->u.i = *pOp->p4.pI64;
  break;
}

#ifndef SQLITE_OMIT_FLOATING_POINT
/* Opcode: Real * P2 * P4 *
**
** P4 is a pointer to a 64-bit floating point value.
** Write that value into register P2.
*/
case OP_Real: {            /* same as TK_FLOAT, out2-prerelease */
  pOut->flags = MEM_Real;
  assert( !sqlite3IsNaN(*pOp->p4.pReal) );
  pOut->r = *pOp->p4.pReal;
  break;
}
#endif

/* Opcode: String8 * P2 * P4 *
**
** P4 points to a nul terminated UTF-8 string. This opcode is transformed 
** into an OP_String before it is executed for the first time.
*/
case OP_String8: {         /* same as TK_STRING, out2-prerelease */

        u.af.iB = (i64)u.af.rB;
        if( u.af.iA==0 ) goto arithmetic_result_is_null;
        if( u.af.iA==-1 ) u.af.iA = 1;
        u.af.rB = (double)(u.af.iB % u.af.iA);
        break;
      }
    }
#ifdef SQLITE_OMIT_FLOATING_POINT
    pOut->u.i = u.af.rB;
    MemSetTypeFlag(pOut, MEM_Int);
#else
    if( sqlite3IsNaN(u.af.rB) ){
      goto arithmetic_result_is_null;
    }
    pOut->r = u.af.rB;
    MemSetTypeFlag(pOut, MEM_Real);
    if( (u.af.flags & MEM_Real)==0 ){
      sqlite3VdbeIntegerAffinity(pOut);
    }
#endif
  }
  break;

arithmetic_result_is_null:
  sqlite3VdbeMemSetNull(pOut);
  break;
}

  u.ag.ctx.isError = 0;
  if( u.ag.ctx.pFunc->flags & SQLITE_FUNC_NEEDCOLL ){
    assert( pOp>aOp );
    assert( pOp[-1].p4type==P4_COLLSEQ );
    assert( pOp[-1].opcode==OP_CollSeq );
    u.ag.ctx.pColl = pOp[-1].p4.pColl;
  }

  (*u.ag.ctx.pFunc->xFunc)(&u.ag.ctx, u.ag.n, u.ag.apVal);




  if( db->mallocFailed ){
    /* Even though a malloc() has failed, the implementation of the
    ** user function may have called an sqlite3_result_XXX() function
    ** to return a value. The following call releases any resources
    ** associated with such a value.




    */
    sqlite3VdbeMemRelease(&u.ag.ctx.s);
    goto no_mem;
  }

  /* If any auxiliary data functions have been called by this user function,
  ** immediately call the destructor for any non-static values.

    }
  }else{
    MemSetTypeFlag(pIn1, MEM_Int);
  }
  break;
}

#ifndef SQLITE_OMIT_FLOATING_POINT
/* Opcode: RealAffinity P1 * * * *
**
** If register P1 holds an integer convert it to a real value.
**
** This opcode is used when extracting information from a column that
** has REAL affinity.  Such column values may still be stored as
** integers, for space efficiency, but after extraction we want them
** to have only a real value.
*/
case OP_RealAffinity: {                  /* in1 */
  pIn1 = &aMem[pOp->p1];
  if( pIn1->flags & MEM_Int ){
    sqlite3VdbeMemRealify(pIn1);
  }
  break;
}
#endif

#ifndef SQLITE_OMIT_CAST
/* Opcode: ToText P1 * * * *
**
** Force the value in register P1 to be text.
** If the value is numeric, convert it to a string using the
** equivalent of printf().  Blob values are unchanged and

  pIn1 = &aMem[pOp->p1];
  if( (pIn1->flags & MEM_Null)==0 ){
    sqlite3VdbeMemIntegerify(pIn1);
  }
  break;
}

#if !defined(SQLITE_OMIT_CAST) && !defined(SQLITE_OMIT_FLOATING_POINT)
/* Opcode: ToReal P1 * * * *
**
** Force the value in register P1 to be a floating point number.
** If The value is currently an integer, convert it.
** If the value is text or blob, try to convert it to an integer using the
** equivalent of atoi() and store 0.0 if no such conversion is possible.
**
** A NULL value is not changed by this routine.  It remains NULL.
*/
case OP_ToReal: {                  /* same as TK_TO_REAL, in1 */
  pIn1 = &aMem[pOp->p1];
  if( (pIn1->flags & MEM_Null)==0 ){
    sqlite3VdbeMemRealify(pIn1);
  }
  break;
}
#endif /* !defined(SQLITE_OMIT_CAST) && !defined(SQLITE_OMIT_FLOATING_POINT) */

/* Opcode: Lt P1 P2 P3 P4 P5
**
** Compare the values in register P1 and P3.  If reg(P3)<reg(P1) then
** jump to address P2.  
**
** If the SQLITE_JUMPIFNULL bit of P5 is set and either reg(P1) or

  int i;             /* Loop counter */
  char *zData;       /* Part of the record being decoded */
  Mem *pDest;        /* Where to write the extracted value */
  Mem sMem;          /* For storing the record being decoded */
  u8 *zIdx;          /* Index into header */
  u8 *zEndHdr;       /* Pointer to first byte after the header */
  u32 offset;        /* Offset into the data */
  u32 szField;       /* Number of bytes in the content of a field */
  int szHdr;         /* Size of the header size field at start of record */
  int avail;         /* Number of bytes of available data */
  Mem *pReg;         /* PseudoTable input register */
#endif /* local variables moved into u.am */


  u.am.p1 = pOp->p1;

    u.am.zIdx = (u8 *)&u.am.zData[u.am.szHdr];

    /* Scan the header and use it to fill in the u.am.aType[] and u.am.aOffset[]
    ** arrays.  u.am.aType[u.am.i] will contain the type integer for the u.am.i-th
    ** column and u.am.aOffset[u.am.i] will contain the u.am.offset from the beginning
    ** of the record to the start of the data for the u.am.i-th column
    */

    for(u.am.i=0; u.am.i<u.am.nField; u.am.i++){
      if( u.am.zIdx<u.am.zEndHdr ){
        u.am.aOffset[u.am.i] = u.am.offset;
        u.am.zIdx += getVarint32(u.am.zIdx, u.am.aType[u.am.i]);
        u.am.szField = sqlite3VdbeSerialTypeLen(u.am.aType[u.am.i]);
        u.am.offset += u.am.szField;
        if( u.am.offset<u.am.szField ){  /* True if u.am.offset overflows */
          u.am.zIdx = &u.am.zEndHdr[1];  /* Forces SQLITE_CORRUPT return below */
          break;
        }
      }else{
        /* If u.am.i is less that u.am.nField, then there are less fields in this
        ** record than SetNumColumns indicated there are columns in the
        ** table. Set the u.am.offset for any extra columns not present in
        ** the record to 0. This tells code below to store a NULL
        ** instead of deserializing a value from the record.
        */
        u.am.aOffset[u.am.i] = 0;
      }
    }
    sqlite3VdbeMemRelease(&u.am.sMem);
    u.am.sMem.flags = MEM_Null;

    /* If we have read more header data than was contained in the header,
    ** or if the end of the last field appears to be past the end of the
    ** record, or if the end of the last field appears to be before the end
    ** of the record (when all fields present), then we must be dealing
    ** with a corrupt database.
    */
    if( (u.am.zIdx > u.am.zEndHdr) || (u.am.offset > u.am.payloadSize)
         || (u.am.zIdx==u.am.zEndHdr && u.am.offset!=u.am.payloadSize) ){
      rc = SQLITE_CORRUPT_BKPT;
      goto op_column_out;
    }
  }

  /* Get the column information. If u.am.aOffset[u.am.p2] is non-zero, then
  ** deserialize the value from the record. If u.am.aOffset[u.am.p2] is zero,

/* Opcode: OpenPseudo P1 P2 P3 * *
**
** Open a new cursor that points to a fake table that contains a single
** row of data.  The content of that one row in the content of memory
** register P2.  In other words, cursor P1 becomes an alias for the 
** MEM_Blob content contained in register P2.
**
** A pseudo-table created by this opcode is used to hold a single
** row output from the sorter so that the row can be decomposed into
** individual columns using the OP_Column opcode.  The OP_Column opcode
** is the only cursor opcode that works with a pseudo-table.
**
** P3 is the number of fields in the records that will be stored by
** the pseudo-table.
*/

  }else if( u.bi.pC->deferredMoveto ){
    u.bi.v = u.bi.pC->movetoTarget;
#ifndef SQLITE_OMIT_VIRTUALTABLE
  }else if( u.bi.pC->pVtabCursor ){
    u.bi.pVtab = u.bi.pC->pVtabCursor->pVtab;
    u.bi.pModule = u.bi.pVtab->pModule;
    assert( u.bi.pModule->xRowid );

    rc = u.bi.pModule->xRowid(u.bi.pC->pVtabCursor, &u.bi.v);
    sqlite3DbFree(db, p->zErrMsg);
    p->zErrMsg = u.bi.pVtab->zErrMsg;
    u.bi.pVtab->zErrMsg = 0;

#endif /* SQLITE_OMIT_VIRTUALTABLE */
  }else{
    assert( u.bi.pC->pCursor!=0 );
    rc = sqlite3VdbeCursorMoveto(u.bi.pC);
    if( rc ) goto abort_due_to_error;
    if( u.bi.pC->rowidIsValid ){
      u.bi.v = u.bi.pC->lastRowid;

  sqlite3BtreeEnterAll(db);
  if( pOp->p2 || DbHasProperty(db, u.bu.iDb, DB_SchemaLoaded) ){
    u.bu.zMaster = SCHEMA_TABLE(u.bu.iDb);
    u.bu.initData.db = db;
    u.bu.initData.iDb = pOp->p1;
    u.bu.initData.pzErrMsg = &p->zErrMsg;
    u.bu.zSql = sqlite3MPrintf(db,
       "SELECT name, rootpage, sql FROM '%q'.%s WHERE %s ORDER BY rowid",
       db->aDb[u.bu.iDb].zName, u.bu.zMaster, pOp->p4.z);
    if( u.bu.zSql==0 ){
      rc = SQLITE_NOMEM;
    }else{

      assert( db->init.busy==0 );
      db->init.busy = 1;
      u.bu.initData.rc = SQLITE_OK;
      assert( !db->mallocFailed );
      rc = sqlite3_exec(db, u.bu.zSql, sqlite3InitCallback, &u.bu.initData, 0);
      if( rc==SQLITE_OK ) rc = u.bu.initData.rc;
      sqlite3DbFree(db, u.bu.zSql);
      db->init.busy = 0;

    }
  }
  sqlite3BtreeLeaveAll(db);
  if( rc==SQLITE_NOMEM ){
    goto no_mem;
  }
  break;

/* Opcode: Vacuum * * * * *
**
** Vacuum the entire database.  This opcode will cause other virtual
** machines to be created and run.  It may not be called from within
** a transaction.
*/
case OP_Vacuum: {

  rc = sqlite3RunVacuum(&p->zErrMsg, db);

  break;
}
#endif

#if !defined(SQLITE_OMIT_AUTOVACUUM)
/* Opcode: IncrVacuum P1 P2 * * *
**

#endif /* local variables moved into u.cf */

  u.cf.pCur = 0;
  u.cf.pVtabCursor = 0;
  u.cf.pVtab = pOp->p4.pVtab->pVtab;
  u.cf.pModule = (sqlite3_module *)u.cf.pVtab->pModule;
  assert(u.cf.pVtab && u.cf.pModule);

  rc = u.cf.pModule->xOpen(u.cf.pVtab, &u.cf.pVtabCursor);
  sqlite3DbFree(db, p->zErrMsg);
  p->zErrMsg = u.cf.pVtab->zErrMsg;
  u.cf.pVtab->zErrMsg = 0;

  if( SQLITE_OK==rc ){
    /* Initialize sqlite3_vtab_cursor base class */
    u.cf.pVtabCursor->pVtab = u.cf.pVtab;

    /* Initialise vdbe cursor object */
    u.cf.pCur = allocateCursor(p, pOp->p1, 0, -1, 0);
    if( u.cf.pCur ){

    u.cg.res = 0;
    u.cg.apArg = p->apArg;
    for(u.cg.i = 0; u.cg.i<u.cg.nArg; u.cg.i++){
      u.cg.apArg[u.cg.i] = &u.cg.pArgc[u.cg.i+1];
      sqlite3VdbeMemStoreType(u.cg.apArg[u.cg.i]);
    }


    p->inVtabMethod = 1;
    rc = u.cg.pModule->xFilter(u.cg.pVtabCursor, u.cg.iQuery, pOp->p4.z, u.cg.nArg, u.cg.apArg);
    p->inVtabMethod = 0;
    sqlite3DbFree(db, p->zErrMsg);
    p->zErrMsg = u.cg.pVtab->zErrMsg;
    u.cg.pVtab->zErrMsg = 0;
    if( rc==SQLITE_OK ){
      u.cg.res = u.cg.pModule->xEof(u.cg.pVtabCursor);
    }


    if( u.cg.res ){
      pc = pOp->p2 - 1;
    }
  }
  u.cg.pCur->nullRow = 0;

  ** the current contents to u.ch.sContext.s so in case the user-function
  ** can use the already allocated buffer instead of allocating a
  ** new one.
  */
  sqlite3VdbeMemMove(&u.ch.sContext.s, u.ch.pDest);
  MemSetTypeFlag(&u.ch.sContext.s, MEM_Null);


  rc = u.ch.pModule->xColumn(pCur->pVtabCursor, &u.ch.sContext, pOp->p2);
  sqlite3DbFree(db, p->zErrMsg);
  p->zErrMsg = u.ch.pVtab->zErrMsg;
  u.ch.pVtab->zErrMsg = 0;
  if( u.ch.sContext.isError ){
    rc = u.ch.sContext.isError;
  }

  /* Copy the result of the function to the P3 register. We
  ** do this regardless of whether or not an error occurred to ensure any
  ** dynamic allocation in u.ch.sContext.s (a Mem struct) is  released.
  */
  sqlite3VdbeChangeEncoding(&u.ch.sContext.s, encoding);
  sqlite3VdbeMemMove(u.ch.pDest, &u.ch.sContext.s);
  REGISTER_TRACE(pOp->p3, u.ch.pDest);
  UPDATE_MAX_BLOBSIZE(u.ch.pDest);




  if( sqlite3VdbeMemTooBig(u.ch.pDest) ){
    goto too_big;
  }
  break;
}
#endif /* SQLITE_OMIT_VIRTUALTABLE */

  /* Invoke the xNext() method of the module. There is no way for the
  ** underlying implementation to return an error if one occurs during
  ** xNext(). Instead, if an error occurs, true is returned (indicating that
  ** data is available) and the error code returned when xColumn or
  ** some other method is next invoked on the save virtual table cursor.
  */

  p->inVtabMethod = 1;
  rc = u.ci.pModule->xNext(u.ci.pCur->pVtabCursor);
  p->inVtabMethod = 0;
  sqlite3DbFree(db, p->zErrMsg);
  p->zErrMsg = u.ci.pVtab->zErrMsg;
  u.ci.pVtab->zErrMsg = 0;
  if( rc==SQLITE_OK ){
    u.ci.res = u.ci.pModule->xEof(u.ci.pCur->pVtabCursor);
  }


  if( !u.ci.res ){
    /* If there is data, jump to P2 */
    pc = pOp->p2 - 1;
  }
  break;
}

#endif /* local variables moved into u.cj */

  u.cj.pVtab = pOp->p4.pVtab->pVtab;
  u.cj.pName = &aMem[pOp->p1];
  assert( u.cj.pVtab->pModule->xRename );
  REGISTER_TRACE(pOp->p1, u.cj.pName);
  assert( u.cj.pName->flags & MEM_Str );

  rc = u.cj.pVtab->pModule->xRename(u.cj.pVtab, u.cj.pName->z);
  sqlite3DbFree(db, p->zErrMsg);
  p->zErrMsg = u.cj.pVtab->zErrMsg;
  u.cj.pVtab->zErrMsg = 0;


  break;
}
#endif

#ifndef SQLITE_OMIT_VIRTUALTABLE
/* Opcode: VUpdate P1 P2 P3 P4 *

    u.ck.apArg = p->apArg;
    u.ck.pX = &aMem[pOp->p3];
    for(u.ck.i=0; u.ck.i<u.ck.nArg; u.ck.i++){
      sqlite3VdbeMemStoreType(u.ck.pX);
      u.ck.apArg[u.ck.i] = u.ck.pX;
      u.ck.pX++;
    }

    rc = u.ck.pModule->xUpdate(u.ck.pVtab, u.ck.nArg, u.ck.apArg, &u.ck.rowid);
    sqlite3DbFree(db, p->zErrMsg);
    p->zErrMsg = u.ck.pVtab->zErrMsg;
    u.ck.pVtab->zErrMsg = 0;

    if( rc==SQLITE_OK && pOp->p1 ){
      assert( u.ck.nArg>1 && u.ck.apArg[0] && (u.ck.apArg[0]->flags&MEM_Null) );
      db->lastRowid = u.ck.rowid;
    }
    p->nChange++;
  }
  break;

/*
** The magic Explain opcode are only inserted when explain==2 (which
** is to say when the EXPLAIN QUERY PLAN syntax is used.)
** This opcode records information from the optimizer.  It is the
** the same as a no-op.  This opcodesnever appears in a real VM program.
*/
default: {          /* This is really OP_Noop and OP_Explain */
  assert( pOp->opcode==OP_Noop || pOp->opcode==OP_Explain );
  break;
}

/*****************************************************************************
** The cases of the switch statement above this line should all be indented
** by 6 spaces.  But the left-most 6 spaces have been removed to improve the
** readability.  From this point on down, the normal indentation rules are

  /* If we reach this point, it means that execution is finished with
  ** an error of some kind.
  */
vdbe_error_halt:
  assert( rc );
  p->rc = rc;
  testcase( sqlite3GlobalConfig.xLog!=0 );
  sqlite3_log(rc, "statement aborts at %d: [%s] %s", 
                   pc, p->zSql, p->zErrMsg);
  sqlite3VdbeHalt(p);
  if( rc==SQLITE_IOERR_NOMEM ) db->mallocFailed = 1;
  rc = SQLITE_ERROR;
  if( resetSchemaOnFault ) sqlite3ResetInternalSchema(db, 0);

  /* This is the only way out of this procedure.  We have to
  ** release the mutexes on btrees that were acquired at the

  */
no_mem:
  db->mallocFailed = 1;
  sqlite3SetString(&p->zErrMsg, db, "out of memory");
  rc = SQLITE_NOMEM;
  goto vdbe_error_halt;







  /* Jump to here for any other kind of fatal error.  The "rc" variable
  ** should hold the error number.
  */
abort_due_to_error:
  assert( p->zErrMsg==0 );
  if( db->mallocFailed ) rc = SQLITE_NOMEM;
  if( rc!=SQLITE_IOERR_NOMEM ){

    rc = SQLITE_NOMEM;
    goto blob_open_out;
  }
  do {
    memset(pParse, 0, sizeof(Parse));
    pParse->db = db;








    sqlite3BtreeEnterAll(db);
    pTab = sqlite3LocateTable(pParse, 0, zTable, zDb);
    if( pTab && IsVirtual(pTab) ){
      pTab = 0;
      sqlite3ErrorMsg(pParse, "cannot open virtual table: %s", zTable);
    }
#ifndef SQLITE_OMIT_VIEW
    if( pTab && pTab->pSelect ){
      pTab = 0;
      sqlite3ErrorMsg(pParse, "cannot open view: %s", zTable);
    }
#endif
    if( !pTab ){
      if( pParse->zErrMsg ){
        sqlite3DbFree(db, zErr);
        zErr = pParse->zErrMsg;
        pParse->zErrMsg = 0;
      }
      rc = SQLITE_ERROR;

      sqlite3BtreeLeaveAll(db);
      goto blob_open_out;
    }

    /* Now search pTab for the exact column. */
    for(iCol=0; iCol < pTab->nCol; iCol++) {
      if( sqlite3StrICmp(pTab->aCol[iCol].zName, zColumn)==0 ){
        break;
      }
    }
    if( iCol==pTab->nCol ){
      sqlite3DbFree(db, zErr);
      zErr = sqlite3MPrintf(db, "no such column: \"%s\"", zColumn);
      rc = SQLITE_ERROR;

      sqlite3BtreeLeaveAll(db);
      goto blob_open_out;
    }

    /* If the value is being opened for writing, check that the
    ** column is not indexed, and that it is not part of a foreign key. 
    ** It is against the rules to open a column to which either of these

          }
        }
      }
      if( zFault ){
        sqlite3DbFree(db, zErr);
        zErr = sqlite3MPrintf(db, "cannot open %s column for writing", zFault);
        rc = SQLITE_ERROR;

        sqlite3BtreeLeaveAll(db);
        goto blob_open_out;
      }
    }

    v = sqlite3VdbeCreate(db);
    if( v ){

      sqlite3VdbeChangeP2(v, 7, pTab->nCol);
      if( !db->mallocFailed ){
        sqlite3VdbeMakeReady(v, 1, 1, 1, 0, 0, 0);
      }
    }
   
    sqlite3BtreeLeaveAll(db);

    if( db->mallocFailed ){
      goto blob_open_out;
    }

    sqlite3_bind_int64((sqlite3_stmt *)v, 1, iRow);
    rc = sqlite3_step((sqlite3_stmt *)v);
    if( rc!=SQLITE_ROW ){
      nAttempt++;

  int (*xCall)(BtCursor*, u32, u32, void*)
){
  int rc;
  Incrblob *p = (Incrblob *)pBlob;
  Vdbe *v;
  sqlite3 *db;

  if( p==0 ) return SQLITE_MISUSE_BKPT;
  db = p->db;
  sqlite3_mutex_enter(db->mutex);
  v = (Vdbe*)p->pStmt;

  if( n<0 || iOffset<0 || (iOffset+n)>p->nByte ){
    /* Request is out of range. Return a transient error. */
    rc = SQLITE_ERROR;

  Parse *pParse,     /* Parsing context for error messages */
  Select *pSelect,   /* The SELECT statement with the ORDER BY clause */
  Expr *pE           /* The specific ORDER BY term */
){
  int i;             /* Loop counter */
  ExprList *pEList;  /* The columns of the result set */
  NameContext nc;    /* Name context for resolving pE */
  sqlite3 *db;       /* Database connection */
  int rc;            /* Return code from subprocedures */
  u8 savedSuppErr;   /* Saved value of db->suppressErr */

  assert( sqlite3ExprIsInteger(pE, &i)==0 );
  pEList = pSelect->pEList;

  /* Resolve all names in the ORDER BY term expression
  */
  memset(&nc, 0, sizeof(nc));
  nc.pParse = pParse;
  nc.pSrcList = pSelect->pSrc;
  nc.pEList = pEList;
  nc.allowAgg = 1;
  nc.nErr = 0;
  db = pParse->db;
  savedSuppErr = db->suppressErr;
  db->suppressErr = 1;
  rc = sqlite3ResolveExprNames(&nc, pE);
  db->suppressErr = savedSuppErr;
  if( rc ) return 0;


  /* Try to match the ORDER BY expression against an expression
  ** in the result set.  Return an 1-based index of the matching
  ** result-set entry.
  */
  for(i=0; i<pEList->nExpr; i++){
    if( sqlite3ExprCompare(pEList->a[i].pExpr, pE)<2 ){
      return i+1;
    }
  }

  /* If no match, return 0. */
  return 0;
}

  char *out = sqlite3DbMallocRaw(sqlite3VdbeDb(v), 8);
  if( out ){
    memcpy(out, in, 8);
  }
  return out;
}

#ifndef SQLITE_OMIT_FLOATING_POINT
/*
** Generate an instruction that will put the floating point
** value described by z[0..n-1] into register iMem.
**
** The z[] string will probably not be zero-terminated.  But the 
** z[n] character is guaranteed to be something that does not look
** like the continuation of the number.
*/
static void codeReal(Vdbe *v, const char *z, int negateFlag, int iMem){
  if( ALWAYS(z!=0) ){
    double value;
    char *zV;
    sqlite3AtoF(z, &value);
    assert( !sqlite3IsNaN(value) ); /* The new AtoF never returns NaN */
    if( negateFlag ) value = -value;
    zV = dup8bytes(v, (char*)&value);
    sqlite3VdbeAddOp4(v, OP_Real, 0, iMem, 0, zV, P4_REAL);
  }
}
#endif


/*
** Generate an instruction that will put the integer describe by
** text z[0..n-1] into register iMem.
**
** The z[] string will probably not be zero-terminated.  But the 
** z[n] character is guaranteed to be something that does not look
** like the continuation of the number.
*/
static void codeInteger(Parse *pParse, Expr *pExpr, int negFlag, int iMem){
  Vdbe *v = pParse->pVdbe;
  if( pExpr->flags & EP_IntValue ){
    int i = pExpr->u.iValue;
    if( negFlag ) i = -i;
    sqlite3VdbeAddOp2(v, OP_Integer, i, iMem);
  }else{
    const char *z = pExpr->u.zToken;
    assert( z!=0 );
    if( sqlite3FitsIn64Bits(z, negFlag) ){
      i64 value;
      char *zV;
      sqlite3Atoi64(z, &value);
      if( negFlag ) value = -value;
      zV = dup8bytes(v, (char*)&value);
      sqlite3VdbeAddOp4(v, OP_Int64, 0, iMem, 0, zV, P4_INT64);
    }else{
#ifdef SQLITE_OMIT_FLOATING_POINT
      sqlite3ErrorMsg(pParse, "oversized integer: %s%s", negFlag ? "-" : "", z);
#else
      codeReal(v, z, negFlag, iMem);
#endif
    }
  }
}

/*
** Clear a cache entry.
*/

      }else{
        inReg = sqlite3ExprCodeGetColumn(pParse, pExpr->pTab,
                                 pExpr->iColumn, pExpr->iTable, target);
      }
      break;
    }
    case TK_INTEGER: {
      codeInteger(pParse, pExpr, 0, target);
      break;
    }
#ifndef SQLITE_OMIT_FLOATING_POINT
    case TK_FLOAT: {
      assert( !ExprHasProperty(pExpr, EP_IntValue) );
      codeReal(v, pExpr->u.zToken, 0, target);
      break;
    }
#endif
    case TK_STRING: {
      assert( !ExprHasProperty(pExpr, EP_IntValue) );
      sqlite3VdbeAddOp4(v, OP_String8, 0, target, 0, pExpr->u.zToken, 0);
      break;
    }
    case TK_NULL: {
      sqlite3VdbeAddOp2(v, OP_Null, 0, target);

      testcase( regFree1==0 );
      testcase( regFree2==0 );
      break;
    }
    case TK_UMINUS: {
      Expr *pLeft = pExpr->pLeft;
      assert( pLeft );
      if( pLeft->op==TK_INTEGER ){
        codeInteger(pParse, pLeft, 1, target);
#ifndef SQLITE_OMIT_FLOATING_POINT
      }else if( pLeft->op==TK_FLOAT ){
        assert( !ExprHasProperty(pExpr, EP_IntValue) );
        codeReal(v, pLeft->u.zToken, 1, target);


#endif
      }else{
        regFree1 = r1 = sqlite3GetTempReg(pParse);
        sqlite3VdbeAddOp2(v, OP_Integer, 0, r1);
        r2 = sqlite3ExprCodeTemp(pParse, pExpr->pLeft, &regFree2);
        sqlite3VdbeAddOp3(v, OP_Subtract, r2, r1, target);
        testcase( regFree2==0 );
      }

      sqlite3VdbeAddOp2(v, OP_Param, p1, target);
      VdbeComment((v, "%s.%s -> $%d",
        (pExpr->iTable ? "new" : "old"),
        (pExpr->iColumn<0 ? "rowid" : pExpr->pTab->aCol[pExpr->iColumn].zName),
        target
      ));

#ifndef SQLITE_OMIT_FLOATING_POINT
      /* If the column has REAL affinity, it may currently be stored as an
      ** integer. Use OP_RealAffinity to make sure it is really real.  */
      if( pExpr->iColumn>=0 
       && pTab->aCol[pExpr->iColumn].affinity==SQLITE_AFF_REAL
      ){
        sqlite3VdbeAddOp1(v, OP_RealAffinity, target);
      }
#endif
      break;
    }


    /*
    ** Form A:
    **   CASE x WHEN e1 THEN r1 WHEN e2 THEN r2 ... WHEN eN THEN rN ELSE y END

    }
  }
  sqlite3ReleaseTempReg(pParse, regFree1);
  sqlite3ReleaseTempReg(pParse, regFree2);
}

/*
** Do a deep comparison of two expression trees.  Return 0 if the two
** expressions are completely identical.  Return 1 if they differ only
** by a COLLATE operator at the top level.  Return 2 if there are differences
** other than the top-level COLLATE operator.
**
** Sometimes this routine will return 2 even if the two expressions
** really are equivalent.  If we cannot prove that the expressions are
** identical, we return 2 just to be safe.  So if this routine
** returns 2, then you do not really know for certain if the two
** expressions are the same.  But if you get a 0 or 1 return, then you
** can be sure the expressions are the same.  In the places where
** this routine is used, it does not hurt to get an extra 2 - that
** just might result in some slightly slower code.  But returning
** an incorrect 0 or 1 could lead to a malfunction.
*/
SQLITE_PRIVATE int sqlite3ExprCompare(Expr *pA, Expr *pB){
  int i;
  if( pA==0||pB==0 ){
    return pB==pA ? 0 : 2;
  }
  assert( !ExprHasAnyProperty(pA, EP_TokenOnly|EP_Reduced) );
  assert( !ExprHasAnyProperty(pB, EP_TokenOnly|EP_Reduced) );
  if( ExprHasProperty(pA, EP_xIsSelect) || ExprHasProperty(pB, EP_xIsSelect) ){
    return 2;
  }
  if( (pA->flags & EP_Distinct)!=(pB->flags & EP_Distinct) ) return 2;
  if( pA->op!=pB->op ) return 2;
  if( sqlite3ExprCompare(pA->pLeft, pB->pLeft) ) return 2;
  if( sqlite3ExprCompare(pA->pRight, pB->pRight) ) return 2;

  if( pA->x.pList && pB->x.pList ){
    if( pA->x.pList->nExpr!=pB->x.pList->nExpr ) return 2;
    for(i=0; i<pA->x.pList->nExpr; i++){
      Expr *pExprA = pA->x.pList->a[i].pExpr;
      Expr *pExprB = pB->x.pList->a[i].pExpr;
      if( sqlite3ExprCompare(pExprA, pExprB) ) return 2;
    }
  }else if( pA->x.pList || pB->x.pList ){
    return 2;
  }

  if( pA->iTable!=pB->iTable || pA->iColumn!=pB->iColumn ) return 2;
  if( ExprHasProperty(pA, EP_IntValue) ){
    if( !ExprHasProperty(pB, EP_IntValue) || pA->u.iValue!=pB->u.iValue ){
      return 2;
    }
  }else if( pA->op!=TK_COLUMN && pA->u.zToken ){
    if( ExprHasProperty(pB, EP_IntValue) || NEVER(pB->u.zToken==0) ) return 2;
    if( sqlite3StrICmp(pA->u.zToken,pB->u.zToken)!=0 ){
      return 2;
    }
  }
  if( (pA->flags & EP_ExpCollate)!=(pB->flags & EP_ExpCollate) ) return 1;
  if( (pA->flags & EP_ExpCollate)!=0 && pA->pColl!=pB->pColl ) return 2;
  return 0;
}


/*
** Add a new element to the pAggInfo->aCol[] array.  Return the index of
** the new element.  Return a negative number if malloc fails.
*/

      ** to be ignored */
      if( pNC->nDepth==0 ){
        /* Check to see if pExpr is a duplicate of another aggregate 
        ** function that is already in the pAggInfo structure
        */
        struct AggInfo_func *pItem = pAggInfo->aFunc;
        for(i=0; i<pAggInfo->nFunc; i++, pItem++){
          if( sqlite3ExprCompare(pItem->pExpr, pExpr)==0 ){
            break;
          }
        }
        if( i>=pAggInfo->nFunc ){
          /* pExpr is original.  Make a new entry in pAggInfo->aFunc[]
          */
          u8 enc = ENC(pParse->db);

#if !defined(SQLITE_OMIT_FOREIGN_KEY) && !defined(SQLITE_OMIT_TRIGGER)
  if( db->flags&SQLITE_ForeignKeys ){
    /* If foreign-key support is enabled, rewrite the CREATE TABLE 
    ** statements corresponding to all child tables of foreign key constraints
    ** for which the renamed table is the parent table.  */
    if( (zWhere=whereForeignKeys(pParse, pTab))!=0 ){
      sqlite3NestedParse(pParse, 
          "UPDATE \"%w\".%s SET "
              "sql = sqlite_rename_parent(sql, %Q, %Q) "
              "WHERE %s;", zDb, SCHEMA_TABLE(iDb), zTabName, zName, zWhere);
      sqlite3DbFree(db, zWhere);
    }
  }
#endif

  /* Modify the sqlite_master table to use the new table name. */
  sqlite3NestedParse(pParse,

  /* Load new statistics out of the sqlite_stat1 table */
  zSql = sqlite3MPrintf(db, 
      "SELECT idx, stat FROM %Q.sqlite_stat1", sInfo.zDatabase);
  if( zSql==0 ){
    rc = SQLITE_NOMEM;
  }else{

    rc = sqlite3_exec(db, zSql, analysisLoader, &sInfo, 0);

    sqlite3DbFree(db, zSql);
  }


  /* Load the statistics from the sqlite_stat2 table. */
#ifdef SQLITE_ENABLE_STAT2
  if( rc==SQLITE_OK && !sqlite3FindTable(db, "sqlite_stat2", sInfo.zDatabase) ){
    rc = SQLITE_ERROR;
  }
  if( rc==SQLITE_OK ){
    sqlite3_stmt *pStmt = 0;

    zSql = sqlite3MPrintf(db, 
        "SELECT idx,sampleno,sample FROM %Q.sqlite_stat2", sInfo.zDatabase);
    if( !zSql ){
      rc = SQLITE_NOMEM;
    }else{

      rc = sqlite3_prepare(db, zSql, -1, &pStmt, 0);

      sqlite3DbFree(db, zSql);
    }

    if( rc==SQLITE_OK ){

      while( sqlite3_step(pStmt)==SQLITE_ROW ){
        char *zIndex = (char *)sqlite3_column_text(pStmt, 0);
        Index *pIdx = sqlite3FindIndex(db, zIndex, sInfo.zDatabase);
        if( pIdx ){
          int iSample = sqlite3_column_int(pStmt, 1);
          sqlite3 *dbMem = pIdx->pTable->dbMem;
          assert( dbMem==db || dbMem==0 );

                }
              }
            }
          }
        }
      }
      rc = sqlite3_finalize(pStmt);

    }
  }
#endif

  if( rc==SQLITE_NOMEM ){
    db->mallocFailed = 1;
  }

      zErrDyn = sqlite3MPrintf(db, 
        "attached databases must use the same text encoding as main database");
      rc = SQLITE_ERROR;
    }
    pPager = sqlite3BtreePager(aNew->pBt);
    sqlite3PagerLockingMode(pPager, db->dfltLockMode);
    sqlite3PagerJournalMode(pPager, db->dfltJournalMode);
    sqlite3BtreeSecureDelete(aNew->pBt,
                             sqlite3BtreeSecureDelete(db->aDb[0].pBt,-1) );
  }
  aNew->safety_level = 3;
  aNew->zName = sqlite3DbStrDup(db, zName);
  if( rc==SQLITE_OK && aNew->zName==0 ){
    rc = SQLITE_NOMEM;
  }


#ifdef SQLITE_HAS_CODEC
  if( rc==SQLITE_OK ){
    extern int sqlite3CodecAttach(sqlite3*, int, const void*, int);
    extern void sqlite3CodecGetKey(sqlite3*, int, void**, int*);
    int nKey;
    char *zKey;
    int t = sqlite3_value_type(argv[2]);
    switch( t ){

  /* If the file was opened successfully, read the schema for the new database.
  ** If this fails, or if opening the file failed, then close the file and 
  ** remove the entry from the db->aDb[] array. i.e. put everything back the way
  ** we found it.
  */
  if( rc==SQLITE_OK ){

    sqlite3BtreeEnterAll(db);
    rc = sqlite3Init(db, &zErrDyn);
    sqlite3BtreeLeaveAll(db);

  }
  if( rc ){
    int iDb = db->nDb - 1;
    assert( iDb>=2 );
    if( db->aDb[iDb].pBt ){
      sqlite3BtreeClose(db->aDb[iDb].pBt);
      db->aDb[iDb].pBt = 0;

    *  See ticket [a696379c1f08866] */
    if( pParse->pAinc!=0 && pParse->nTab==0 ) pParse->nTab = 1;
    sqlite3VdbeMakeReady(v, pParse->nVar, pParse->nMem,
                         pParse->nTab, pParse->nMaxArg, pParse->explain,
                         pParse->isMultiWrite && pParse->mayAbort);
    pParse->rc = SQLITE_DONE;
    pParse->colNamesSet = 0;
  }else{
    pParse->rc = SQLITE_ERROR;
  }
  pParse->nTab = 0;
  pParse->nMem = 0;
  pParse->nSet = 0;
  pParse->nVar = 0;
  pParse->cookieMask = 0;

  int iDb;

  if( db->mallocFailed ){
    goto exit_drop_table;
  }
  assert( pParse->nErr==0 );
  assert( pName->nSrc==1 );
  if( noErr ) db->suppressErr++;
  pTab = sqlite3LocateTable(pParse, isView, 
                            pName->a[0].zName, pName->a[0].zDatabase);
  if( noErr ) db->suppressErr--;

  if( pTab==0 ){



    goto exit_drop_table;
  }
  iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
  assert( iDb>=0 && iDb<db->nDb );

  /* If pTab is a virtual table, call ViewGetColumnNames() to ensure
  ** it is initialized.

** Make sure the TEMP database is open and available for use.  Return
** the number of errors.  Leave any error messages in the pParse structure.
*/
SQLITE_PRIVATE int sqlite3OpenTempDatabase(Parse *pParse){
  sqlite3 *db = pParse->db;
  if( db->aDb[1].pBt==0 && !pParse->explain ){
    int rc;
    Btree *pBt;
    static const int flags = 
          SQLITE_OPEN_READWRITE |
          SQLITE_OPEN_CREATE |
          SQLITE_OPEN_EXCLUSIVE |
          SQLITE_OPEN_DELETEONCLOSE |
          SQLITE_OPEN_TEMP_DB;

    rc = sqlite3BtreeFactory(db, 0, 0, SQLITE_DEFAULT_CACHE_SIZE, flags, &pBt);

    if( rc!=SQLITE_OK ){
      sqlite3ErrorMsg(pParse, "unable to open a temporary database "
        "file for storing temporary tables");
      pParse->rc = rc;
      return 1;
    }
    db->aDb[1].pBt = pBt;
    assert( db->aDb[1].pSchema );
    if( SQLITE_NOMEM==sqlite3BtreeSetPageSize(pBt, db->nextPagesize, -1, 0) ){
      db->mallocFailed = 1;
      return 1;
    }
    sqlite3PagerJournalMode(sqlite3BtreePager(pBt), db->dfltJournalMode);

  }
  return 0;
}

/*
** Generate VDBE code that will verify the schema cookie and start
** a read-transaction for all named database files.

    sqlite3HashInit(&p->fkeyHash);
    p->enc = SQLITE_UTF8;
  }
  return p;
}

/************** End of callback.c ********************************************/
/************** Begin file ctime.c *******************************************/
/*
** 2010 February 23
**
** The author disclaims copyright to this source code.  In place of
** a legal notice, here is a blessing:
**
**    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 implements routines used to report what compile-time options
** SQLite was built with.
*/

#ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS


/*
** An array of names of all compile-time options.  This array should 
** be sorted A-Z.
**
** This array looks large, but in a typical installation actually uses
** only a handful of compile-time options, so most times this array is usually
** rather short and uses little memory space.
*/
static const char * const azCompileOpt[] = {

/* These macros are provided to "stringify" the value of the define
** for those options in which the value is meaningful. */
#define CTIMEOPT_VAL_(opt) #opt
#define CTIMEOPT_VAL(opt) CTIMEOPT_VAL_(opt)

#ifdef SQLITE_32BIT_ROWID
  "32BIT_ROWID",
#endif
#ifdef SQLITE_4_BYTE_ALIGNED_MALLOC
  "4_BYTE_ALIGNED_MALLOC",
#endif
#ifdef SQLITE_CASE_SENSITIVE_LIKE
  "CASE_SENSITIVE_LIKE",
#endif
#ifdef SQLITE_CHECK_PAGES
  "CHECK_PAGES",
#endif
#ifdef SQLITE_COVERAGE_TEST
  "COVERAGE_TEST",
#endif
#ifdef SQLITE_DEBUG
  "DEBUG",
#endif
#ifdef SQLITE_DEFAULT_LOCKING_MODE
  "DEFAULT_LOCKING_MODE=" CTIMEOPT_VAL(SQLITE_DEFAULT_LOCKING_MODE),
#endif
#ifdef SQLITE_DISABLE_DIRSYNC
  "DISABLE_DIRSYNC",
#endif
#ifdef SQLITE_DISABLE_LFS
  "DISABLE_LFS",
#endif
#ifdef SQLITE_ENABLE_ATOMIC_WRITE
  "ENABLE_ATOMIC_WRITE",
#endif
#ifdef SQLITE_ENABLE_CEROD
  "ENABLE_CEROD",
#endif
#ifdef SQLITE_ENABLE_COLUMN_METADATA
  "ENABLE_COLUMN_METADATA",
#endif
#ifdef SQLITE_ENABLE_EXPENSIVE_ASSERT
  "ENABLE_EXPENSIVE_ASSERT",
#endif
#ifdef SQLITE_ENABLE_FTS1
  "ENABLE_FTS1",
#endif
#ifdef SQLITE_ENABLE_FTS2
  "ENABLE_FTS2",
#endif
#ifdef SQLITE_ENABLE_FTS3
  "ENABLE_FTS3",
#endif
#ifdef SQLITE_ENABLE_FTS3_PARENTHESIS
  "ENABLE_FTS3_PARENTHESIS",
#endif
#ifdef SQLITE_ENABLE_FTS4
  "ENABLE_FTS4",
#endif
#ifdef SQLITE_ENABLE_ICU
  "ENABLE_ICU",
#endif
#ifdef SQLITE_ENABLE_IOTRACE
  "ENABLE_IOTRACE",
#endif
#ifdef SQLITE_ENABLE_LOAD_EXTENSION
  "ENABLE_LOAD_EXTENSION",
#endif
#ifdef SQLITE_ENABLE_LOCKING_STYLE
  "ENABLE_LOCKING_STYLE=" CTIMEOPT_VAL(SQLITE_ENABLE_LOCKING_STYLE),
#endif
#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
  "ENABLE_MEMORY_MANAGEMENT",
#endif
#ifdef SQLITE_ENABLE_MEMSYS3
  "ENABLE_MEMSYS3",
#endif
#ifdef SQLITE_ENABLE_MEMSYS5
  "ENABLE_MEMSYS5",
#endif
#ifdef SQLITE_ENABLE_OVERSIZE_CELL_CHECK
  "ENABLE_OVERSIZE_CELL_CHECK",
#endif
#ifdef SQLITE_ENABLE_RTREE
  "ENABLE_RTREE",
#endif
#ifdef SQLITE_ENABLE_STAT2
  "ENABLE_STAT2",
#endif
#ifdef SQLITE_ENABLE_UNLOCK_NOTIFY
  "ENABLE_UNLOCK_NOTIFY",
#endif
#ifdef SQLITE_ENABLE_UPDATE_DELETE_LIMIT
  "ENABLE_UPDATE_DELETE_LIMIT",
#endif
#ifdef SQLITE_HAS_CODEC
  "HAS_CODEC",
#endif
#ifdef SQLITE_HAVE_ISNAN
  "HAVE_ISNAN",
#endif
#ifdef SQLITE_HOMEGROWN_RECURSIVE_MUTEX
  "HOMEGROWN_RECURSIVE_MUTEX",
#endif
#ifdef SQLITE_IGNORE_AFP_LOCK_ERRORS
  "IGNORE_AFP_LOCK_ERRORS",
#endif
#ifdef SQLITE_IGNORE_FLOCK_LOCK_ERRORS
  "IGNORE_FLOCK_LOCK_ERRORS",
#endif
#ifdef SQLITE_INT64_TYPE
  "INT64_TYPE",
#endif
#ifdef SQLITE_LOCK_TRACE
  "LOCK_TRACE",
#endif
#ifdef SQLITE_MEMDEBUG
  "MEMDEBUG",
#endif
#ifdef SQLITE_MIXED_ENDIAN_64BIT_FLOAT
  "MIXED_ENDIAN_64BIT_FLOAT",
#endif
#ifdef SQLITE_NO_SYNC
  "NO_SYNC",
#endif
#ifdef SQLITE_OMIT_ALTERTABLE
  "OMIT_ALTERTABLE",
#endif
#ifdef SQLITE_OMIT_ANALYZE
  "OMIT_ANALYZE",
#endif
#ifdef SQLITE_OMIT_ATTACH
  "OMIT_ATTACH",
#endif
#ifdef SQLITE_OMIT_AUTHORIZATION
  "OMIT_AUTHORIZATION",
#endif
#ifdef SQLITE_OMIT_AUTOINCREMENT
  "OMIT_AUTOINCREMENT",
#endif
#ifdef SQLITE_OMIT_AUTOINIT
  "OMIT_AUTOINIT",
#endif
#ifdef SQLITE_OMIT_AUTOVACUUM
  "OMIT_AUTOVACUUM",
#endif
#ifdef SQLITE_OMIT_BETWEEN_OPTIMIZATION
  "OMIT_BETWEEN_OPTIMIZATION",
#endif
#ifdef SQLITE_OMIT_BLOB_LITERAL
  "OMIT_BLOB_LITERAL",
#endif
#ifdef SQLITE_OMIT_BTREECOUNT
  "OMIT_BTREECOUNT",
#endif
#ifdef SQLITE_OMIT_BUILTIN_TEST
  "OMIT_BUILTIN_TEST",
#endif
#ifdef SQLITE_OMIT_CAST
  "OMIT_CAST",
#endif
#ifdef SQLITE_OMIT_CHECK
  "OMIT_CHECK",
#endif
#ifdef SQLITE_OMIT_COMPILEOPTION_DIAGS
  "OMIT_COMPILEOPTION_DIAGS",
#endif
#ifdef SQLITE_OMIT_COMPLETE
  "OMIT_COMPLETE",
#endif
#ifdef SQLITE_OMIT_COMPOUND_SELECT
  "OMIT_COMPOUND_SELECT",
#endif
#ifdef SQLITE_OMIT_DATETIME_FUNCS
  "OMIT_DATETIME_FUNCS",
#endif
#ifdef SQLITE_OMIT_DECLTYPE
  "OMIT_DECLTYPE",
#endif
#ifdef SQLITE_OMIT_DEPRECATED
  "OMIT_DEPRECATED",
#endif
#ifdef SQLITE_OMIT_DISKIO
  "OMIT_DISKIO",
#endif
#ifdef SQLITE_OMIT_EXPLAIN
  "OMIT_EXPLAIN",
#endif
#ifdef SQLITE_OMIT_FLAG_PRAGMAS
  "OMIT_FLAG_PRAGMAS",
#endif
#ifdef SQLITE_OMIT_FLOATING_POINT
  "OMIT_FLOATING_POINT",
#endif
#ifdef SQLITE_OMIT_FOREIGN_KEY
  "OMIT_FOREIGN_KEY",
#endif
#ifdef SQLITE_OMIT_GET_TABLE
  "OMIT_GET_TABLE",
#endif
#ifdef SQLITE_OMIT_GLOBALRECOVER
  "OMIT_GLOBALRECOVER",
#endif
#ifdef SQLITE_OMIT_INCRBLOB
  "OMIT_INCRBLOB",
#endif
#ifdef SQLITE_OMIT_INTEGRITY_CHECK
  "OMIT_INTEGRITY_CHECK",
#endif
#ifdef SQLITE_OMIT_LIKE_OPTIMIZATION
  "OMIT_LIKE_OPTIMIZATION",
#endif
#ifdef SQLITE_OMIT_LOAD_EXTENSION
  "OMIT_LOAD_EXTENSION",
#endif
#ifdef SQLITE_OMIT_LOCALTIME
  "OMIT_LOCALTIME",
#endif
#ifdef SQLITE_OMIT_LOOKASIDE
  "OMIT_LOOKASIDE",
#endif
#ifdef SQLITE_OMIT_MEMORYDB
  "OMIT_MEMORYDB",
#endif
#ifdef SQLITE_OMIT_OR_OPTIMIZATION
  "OMIT_OR_OPTIMIZATION",
#endif
#ifdef SQLITE_OMIT_PAGER_PRAGMAS
  "OMIT_PAGER_PRAGMAS",
#endif
#ifdef SQLITE_OMIT_PRAGMA
  "OMIT_PRAGMA",
#endif
#ifdef SQLITE_OMIT_PROGRESS_CALLBACK
  "OMIT_PROGRESS_CALLBACK",
#endif
#ifdef SQLITE_OMIT_QUICKBALANCE
  "OMIT_QUICKBALANCE",
#endif
#ifdef SQLITE_OMIT_REINDEX
  "OMIT_REINDEX",
#endif
#ifdef SQLITE_OMIT_SCHEMA_PRAGMAS
  "OMIT_SCHEMA_PRAGMAS",
#endif
#ifdef SQLITE_OMIT_SCHEMA_VERSION_PRAGMAS
  "OMIT_SCHEMA_VERSION_PRAGMAS",
#endif
#ifdef SQLITE_OMIT_SHARED_CACHE
  "OMIT_SHARED_CACHE",
#endif
#ifdef SQLITE_OMIT_SUBQUERY
  "OMIT_SUBQUERY",
#endif
#ifdef SQLITE_OMIT_TCL_VARIABLE
  "OMIT_TCL_VARIABLE",
#endif
#ifdef SQLITE_OMIT_TEMPDB
  "OMIT_TEMPDB",
#endif
#ifdef SQLITE_OMIT_TRACE
  "OMIT_TRACE",
#endif
#ifdef SQLITE_OMIT_TRIGGER
  "OMIT_TRIGGER",
#endif
#ifdef SQLITE_OMIT_TRUNCATE_OPTIMIZATION
  "OMIT_TRUNCATE_OPTIMIZATION",
#endif
#ifdef SQLITE_OMIT_UTF16
  "OMIT_UTF16",
#endif
#ifdef SQLITE_OMIT_VACUUM
  "OMIT_VACUUM",
#endif
#ifdef SQLITE_OMIT_VIEW
  "OMIT_VIEW",
#endif
#ifdef SQLITE_OMIT_VIRTUALTABLE
  "OMIT_VIRTUALTABLE",
#endif
#ifdef SQLITE_OMIT_WSD
  "OMIT_WSD",
#endif
#ifdef SQLITE_OMIT_XFER_OPT
  "OMIT_XFER_OPT",
#endif
#ifdef SQLITE_PERFORMANCE_TRACE
  "PERFORMANCE_TRACE",
#endif
#ifdef SQLITE_PROXY_DEBUG
  "PROXY_DEBUG",
#endif
#ifdef SQLITE_SECURE_DELETE
  "SECURE_DELETE",
#endif
#ifdef SQLITE_SMALL_STACK
  "SMALL_STACK",
#endif
#ifdef SQLITE_SOUNDEX
  "SOUNDEX",
#endif
#ifdef SQLITE_TCL
  "TCL",
#endif
#ifdef SQLITE_TEMP_STORE
  "TEMP_STORE=" CTIMEOPT_VAL(SQLITE_TEMP_STORE),
#endif
#ifdef SQLITE_TEST
  "TEST",
#endif
#ifdef SQLITE_THREADSAFE
  "THREADSAFE=" CTIMEOPT_VAL(SQLITE_THREADSAFE),
#endif
#ifdef SQLITE_USE_ALLOCA
  "USE_ALLOCA",
#endif
#ifdef SQLITE_ZERO_MALLOC
  "ZERO_MALLOC"
#endif
};

/*
** Given the name of a compile-time option, return true if that option
** was used and false if not.
**
** The name can optionally begin with "SQLITE_" but the "SQLITE_" prefix
** is not required for a match.
*/
SQLITE_API int sqlite3_compileoption_used(const char *zOptName){
  int i, n;
  if( sqlite3StrNICmp(zOptName, "SQLITE_", 7)==0 ) zOptName += 7;
  n = sqlite3Strlen30(zOptName);

  /* Since ArraySize(azCompileOpt) is normally in single digits, a
  ** linear search is adequate.  No need for a binary search. */
  for(i=0; i<ArraySize(azCompileOpt); i++){
    if(   (sqlite3StrNICmp(zOptName, azCompileOpt[i], n)==0)
       && ( (azCompileOpt[i][n]==0) || (azCompileOpt[i][n]=='=') ) ) return 1;
  }
  return 0;
}

/*
** Return the N-th compile-time option string.  If N is out of range,
** return a NULL pointer.
*/
SQLITE_API const char *sqlite3_compileoption_get(int N){
  if( N>=0 && N<ArraySize(azCompileOpt) ){
    return azCompileOpt[N];
  }
  return 0;
}

#endif /* SQLITE_OMIT_COMPILEOPTION_DIAGS */

/************** End of ctime.c ***********************************************/
/************** Begin file delete.c ******************************************/
/*
** 2001 September 15
**
** The author disclaims copyright to this source code.  In place of
** a legal notice, here is a blessing:
**