Fossil

  data->mode = MODE_List;
  memcpy(data->separator,"|", 2);
  memcpy(data->newline,"\r\n", 3);
  data->showHeader = 0;
  data->shellFlgs = SHFLG_Lookaside;
  sqlite3_config(SQLITE_CONFIG_URI, 1);
  sqlite3_config(SQLITE_CONFIG_LOG, shellLog, data);

  sqlite3_snprintf(sizeof(mainPrompt), mainPrompt,"sqlite> ");
  sqlite3_snprintf(sizeof(continuePrompt), continuePrompt,"   ...> ");
  sqlite3_config(SQLITE_CONFIG_SINGLETHREAD);
}

/*
** Output text to the console in a font that attracts extra attention.
*/
#ifdef _WIN32
static void printBold(const char *zText){

      zSize = cmdline_option_value(argc, argv, ++i);
      szHeap = integerValue(zSize);
      if( szHeap>0x7fff0000 ) szHeap = 0x7fff0000;
      sqlite3_config(SQLITE_CONFIG_HEAP, malloc((int)szHeap), (int)szHeap, 64);
#endif
    }else if( strcmp(z,"-scratch")==0 ){
      int n, sz;
      sz = integerValue(cmdline_option_value(argc,argv,++i));
      if( sz>400000 ) sz = 400000;
      if( sz<2500 ) sz = 2500;
      n = integerValue(cmdline_option_value(argc,argv,++i));
      if( n>10 ) n = 10;
      if( n<1 ) n = 1;
      sqlite3_config(SQLITE_CONFIG_SCRATCH, malloc(n*sz+1), sz, n);
      data.shellFlgs |= SHFLG_Scratch;
    }else if( strcmp(z,"-pagecache")==0 ){
      int n, sz;
      sz = integerValue(cmdline_option_value(argc,argv,++i));
      if( sz>70000 ) sz = 70000;
      if( sz<800 ) sz = 800;
      n = integerValue(cmdline_option_value(argc,argv,++i));
      if( n<10 ) n = 10;
      sqlite3_config(SQLITE_CONFIG_PAGECACHE, malloc(n*sz+1), sz, n);
      data.shellFlgs |= SHFLG_Pagecache;
    }else if( strcmp(z,"-lookaside")==0 ){
      int n, sz;
      sz = integerValue(cmdline_option_value(argc,argv,++i));
      if( sz<0 ) sz = 0;
      n = integerValue(cmdline_option_value(argc,argv,++i));
      if( n<0 ) n = 0;
      sqlite3_config(SQLITE_CONFIG_LOOKASIDE, sz, n);
      if( sz*n==0 ) data.shellFlgs &= ~SHFLG_Lookaside;
#ifdef SQLITE_ENABLE_VFSTRACE
    }else if( strcmp(z,"-vfstrace")==0 ){
      extern int vfstrace_register(
         const char *zTraceName,

/******************************************************************************
** This file is an amalgamation of many separate C source files from SQLite
** version 3.8.6.  By combining all the individual C code files into this 
** single large file, the entire code can be compiled as a single translation
** unit.  This allows many compilers to do optimizations that would not be
** possible if the files were compiled separately.  Performance improvements
** of 5% or more are commonly seen when SQLite is compiled as a single
** translation unit.
**
** This file is all you need to compile SQLite.  To use SQLite in other

** 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        "3.8.6"
#define SQLITE_VERSION_NUMBER 3008006
#define SQLITE_SOURCE_ID      "2014-08-15 11:46:33 9491ba7d738528f168657adb43a198238abde19e"

/*
** 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

**
** [[SQLITE_LIMIT_VARIABLE_NUMBER]]
** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt>
** <dd>The maximum index number of any [parameter] in an SQL statement.)^
**
** [[SQLITE_LIMIT_TRIGGER_DEPTH]] ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt>
** <dd>The maximum depth of recursion for triggers.</dd>)^




** </dl>
*/
#define SQLITE_LIMIT_LENGTH                    0
#define SQLITE_LIMIT_SQL_LENGTH                1
#define SQLITE_LIMIT_COLUMN                    2
#define SQLITE_LIMIT_EXPR_DEPTH                3
#define SQLITE_LIMIT_COMPOUND_SELECT           4
#define SQLITE_LIMIT_VDBE_OP                   5
#define SQLITE_LIMIT_FUNCTION_ARG              6
#define SQLITE_LIMIT_ATTACHED                  7
#define SQLITE_LIMIT_LIKE_PATTERN_LENGTH       8
#define SQLITE_LIMIT_VARIABLE_NUMBER           9
#define SQLITE_LIMIT_TRIGGER_DEPTH            10


/*
** CAPI3REF: Compiling An SQL Statement
** KEYWORDS: {SQL statement compiler}
**
** To execute an SQL query, it must first be compiled into a byte-code
** program using one of these routines.

#define SQLITE_TESTCTRL_SCRATCHMALLOC           17
#define SQLITE_TESTCTRL_LOCALTIME_FAULT         18
#define SQLITE_TESTCTRL_EXPLAIN_STMT            19
#define SQLITE_TESTCTRL_NEVER_CORRUPT           20
#define SQLITE_TESTCTRL_VDBE_COVERAGE           21
#define SQLITE_TESTCTRL_BYTEORDER               22
#define SQLITE_TESTCTRL_ISINIT                  23

#define SQLITE_TESTCTRL_LAST                    23

/*
** CAPI3REF: SQLite Runtime Status
**
** ^This interface is used to retrieve runtime status information
** about the performance of SQLite, and optionally to reset various
** highwater marks.  ^The first argument is an integer code for

# 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 0, 1, or 2.
** 0 means mutexes are permanently disable and the library is never
** threadsafe.  1 means the library is serialized which is the highest
** level of threadsafety.  2 means the library is multithreaded - multiple
** threads can use SQLite as long as no two threads try to use the same
** database connection at the same time.

**
** Again, this structure is intended to be opaque, but it can't really
** be opaque because it is used by macros.
*/
struct HashElem {
  HashElem *next, *prev;       /* Next and previous elements in the table */
  void *data;                  /* Data associated with this element */
  const char *pKey; int nKey;  /* Key associated with this element */
};

/*
** Access routines.  To delete, insert a NULL pointer.
*/
SQLITE_PRIVATE void sqlite3HashInit(Hash*);
SQLITE_PRIVATE void *sqlite3HashInsert(Hash*, const char *pKey, int nKey, void *pData);
SQLITE_PRIVATE void *sqlite3HashFind(const Hash*, const char *pKey, int nKey);
SQLITE_PRIVATE void sqlite3HashClear(Hash*);

/*
** Macros for looping over all elements of a hash table.  The idiom is
** like this:
**
**   Hash h;

** Provide a default value for SQLITE_TEMP_STORE in case it is not specified
** on the command-line
*/
#ifndef SQLITE_TEMP_STORE
# define SQLITE_TEMP_STORE 1
# define SQLITE_TEMP_STORE_xc 1  /* Exclude from ctime.c */
#endif






















/*
** GCC does not define the offsetof() macro so we'll have to do it
** ourselves.
*/
#ifndef offsetof
#define offsetof(STRUCTURE,FIELD) ((int)((char*)&((STRUCTURE*)0)->FIELD))

typedef struct Module Module;
typedef struct NameContext NameContext;
typedef struct Parse Parse;
typedef struct PrintfArguments PrintfArguments;
typedef struct RowSet RowSet;
typedef struct Savepoint Savepoint;
typedef struct Select Select;

typedef struct SelectDest SelectDest;
typedef struct SrcList SrcList;
typedef struct StrAccum StrAccum;
typedef struct Table Table;
typedef struct TableLock TableLock;
typedef struct Token Token;
typedef struct Trigger Trigger;

SQLITE_PRIVATE int sqlite3BtreeMovetoUnpacked(
  BtCursor*,
  UnpackedRecord *pUnKey,
  i64 intKey,
  int bias,
  int *pRes
);
SQLITE_PRIVATE int sqlite3BtreeCursorHasMoved(BtCursor*, int*);

SQLITE_PRIVATE int sqlite3BtreeDelete(BtCursor*);
SQLITE_PRIVATE int sqlite3BtreeInsert(BtCursor*, const void *pKey, i64 nKey,
                                  const void *pData, int nData,
                                  int nZero, int bias, int seekResult);
SQLITE_PRIVATE int sqlite3BtreeFirst(BtCursor*, int *pRes);
SQLITE_PRIVATE int sqlite3BtreeLast(BtCursor*, int *pRes);
SQLITE_PRIVATE int sqlite3BtreeNext(BtCursor*, int *pRes);

#define OP_Copy           33 /* synopsis: r[P2@P3+1]=r[P1@P3+1]            */
#define OP_SCopy          34 /* synopsis: r[P2]=r[P1]                      */
#define OP_ResultRow      35 /* synopsis: output=r[P1@P2]                  */
#define OP_CollSeq        36
#define OP_AddImm         37 /* synopsis: r[P1]=r[P1]+P2                   */
#define OP_MustBeInt      38
#define OP_RealAffinity   39

#define OP_Permutation    40
#define OP_Compare        41 /* synopsis: r[P1@P3] <-> r[P2@P3]            */
#define OP_Jump           42
#define OP_Once           43
#define OP_If             44
#define OP_IfNot          45
#define OP_Column         46 /* synopsis: r[P3]=PX                         */
#define OP_Affinity       47 /* synopsis: affinity(r[P1@P2])               */
#define OP_MakeRecord     48 /* synopsis: r[P3]=mkrec(r[P1@P2])            */
#define OP_Count          49 /* synopsis: r[P2]=count()                    */
#define OP_ReadCookie     50
#define OP_SetCookie      51
#define OP_ReopenIdx      52 /* synopsis: root=P2 iDb=P3                   */
#define OP_OpenRead       53 /* synopsis: root=P2 iDb=P3                   */
#define OP_OpenWrite      54 /* synopsis: root=P2 iDb=P3                   */
#define OP_OpenAutoindex  55 /* synopsis: nColumn=P2                       */
#define OP_OpenEphemeral  56 /* synopsis: nColumn=P2                       */
#define OP_SorterOpen     57

#define OP_OpenPseudo     58 /* synopsis: P3 columns in r[P2]              */
#define OP_Close          59
#define OP_SeekLT         60 /* synopsis: key=r[P3@P4]                     */
#define OP_SeekLE         61 /* synopsis: key=r[P3@P4]                     */
#define OP_SeekGE         62 /* synopsis: key=r[P3@P4]                     */
#define OP_SeekGT         63 /* synopsis: key=r[P3@P4]                     */
#define OP_Seek           64 /* synopsis: intkey=r[P2]                     */
#define OP_NoConflict     65 /* synopsis: key=r[P3@P4]                     */
#define OP_NotFound       66 /* synopsis: key=r[P3@P4]                     */
#define OP_Found          67 /* synopsis: key=r[P3@P4]                     */
#define OP_NotExists      68 /* synopsis: intkey=r[P3]                     */
#define OP_Sequence       69 /* synopsis: r[P2]=cursor[P1].ctr++           */
#define OP_NewRowid       70 /* synopsis: r[P2]=rowid                      */
#define OP_Or             71 /* same as TK_OR, synopsis: r[P3]=(r[P1] || r[P2]) */
#define OP_And            72 /* same as TK_AND, synopsis: r[P3]=(r[P1] && r[P2]) */
#define OP_Insert         73 /* synopsis: intkey=r[P3] data=r[P2]          */
#define OP_InsertInt      74 /* synopsis: intkey=P3 data=r[P2]             */
#define OP_Delete         75
#define OP_IsNull         76 /* same as TK_ISNULL, synopsis: if r[P1]==NULL goto P2 */
#define OP_NotNull        77 /* same as TK_NOTNULL, synopsis: if r[P1]!=NULL goto P2 */
#define OP_Ne             78 /* same as TK_NE, synopsis: if r[P1]!=r[P3] goto P2 */
#define OP_Eq             79 /* same as TK_EQ, synopsis: if r[P1]==r[P3] goto P2 */
#define OP_Gt             80 /* same as TK_GT, synopsis: if r[P1]>r[P3] goto P2 */
#define OP_Le             81 /* same as TK_LE, synopsis: if r[P1]<=r[P3] goto P2 */
#define OP_Lt             82 /* same as TK_LT, synopsis: if r[P1]<r[P3] goto P2 */
#define OP_Ge             83 /* same as TK_GE, synopsis: if r[P1]>=r[P3] goto P2 */
#define OP_ResetCount     84
#define OP_BitAnd         85 /* same as TK_BITAND, synopsis: r[P3]=r[P1]&r[P2] */
#define OP_BitOr          86 /* same as TK_BITOR, synopsis: r[P3]=r[P1]|r[P2] */
#define OP_ShiftLeft      87 /* same as TK_LSHIFT, synopsis: r[P3]=r[P2]<<r[P1] */
#define OP_ShiftRight     88 /* same as TK_RSHIFT, synopsis: r[P3]=r[P2]>>r[P1] */
#define OP_Add            89 /* same as TK_PLUS, synopsis: r[P3]=r[P1]+r[P2] */
#define OP_Subtract       90 /* same as TK_MINUS, synopsis: r[P3]=r[P2]-r[P1] */
#define OP_Multiply       91 /* same as TK_STAR, synopsis: r[P3]=r[P1]*r[P2] */
#define OP_Divide         92 /* same as TK_SLASH, synopsis: r[P3]=r[P2]/r[P1] */
#define OP_Remainder      93 /* same as TK_REM, synopsis: r[P3]=r[P2]%r[P1] */
#define OP_Concat         94 /* same as TK_CONCAT, synopsis: r[P3]=r[P2]+r[P1] */
#define OP_SorterCompare  95 /* synopsis: if key(P1)!=trim(r[P3],P4) goto P2 */
#define OP_BitNot         96 /* same as TK_BITNOT, synopsis: r[P1]= ~r[P1] */
#define OP_String8        97 /* same as TK_STRING, synopsis: r[P2]='P4'    */


#define OP_SorterData     98 /* synopsis: r[P2]=data                       */
#define OP_RowKey         99 /* synopsis: r[P2]=key                        */
#define OP_RowData       100 /* synopsis: r[P2]=data                       */
#define OP_Rowid         101 /* synopsis: r[P2]=rowid                      */
#define OP_NullRow       102
#define OP_Last          103
#define OP_SorterSort    104
#define OP_Sort          105
#define OP_Rewind        106
#define OP_SorterInsert  107
#define OP_IdxInsert     108 /* synopsis: key=r[P2]                        */
#define OP_IdxDelete     109 /* synopsis: key=r[P2@P3]                     */
#define OP_IdxRowid      110 /* synopsis: r[P2]=rowid                      */
#define OP_IdxLE         111 /* synopsis: key=r[P3@P4]                     */
#define OP_IdxGT         112 /* synopsis: key=r[P3@P4]                     */
#define OP_IdxLT         113 /* synopsis: key=r[P3@P4]                     */
#define OP_IdxGE         114 /* synopsis: key=r[P3@P4]                     */
#define OP_Destroy       115
#define OP_Clear         116
#define OP_ResetSorter   117
#define OP_CreateIndex   118 /* synopsis: r[P2]=root iDb=P1                */
#define OP_CreateTable   119 /* synopsis: r[P2]=root iDb=P1                */
#define OP_ParseSchema   120
#define OP_LoadAnalysis  121
#define OP_DropTable     122
#define OP_DropIndex     123
#define OP_DropTrigger   124
#define OP_IntegrityCk   125
#define OP_RowSetAdd     126 /* synopsis: rowset(P1)=r[P2]                 */
#define OP_RowSetRead    127 /* synopsis: r[P3]=rowset(P1)                 */
#define OP_RowSetTest    128 /* synopsis: if r[P3] in rowset(P1) goto P2   */
#define OP_Program       129
#define OP_Param         130
#define OP_FkCounter     131 /* synopsis: fkctr[P1]+=P2                    */
#define OP_FkIfZero      132 /* synopsis: if fkctr[P1]==0 goto P2          */
#define OP_Real          133 /* same as TK_FLOAT, synopsis: r[P2]=P4       */


#define OP_MemMax        134 /* synopsis: r[P1]=max(r[P1],r[P2])           */
#define OP_IfPos         135 /* synopsis: if r[P1]>0 goto P2               */
#define OP_IfNeg         136 /* synopsis: r[P1]+=P3, if r[P1]<0 goto P2    */
#define OP_IfZero        137 /* synopsis: r[P1]+=P3, if r[P1]==0 goto P2   */
#define OP_AggFinal      138 /* synopsis: accum=r[P1] N=P2                 */
#define OP_IncrVacuum    139
#define OP_Expire        140
#define OP_TableLock     141 /* synopsis: iDb=P1 root=P2 write=P3          */
#define OP_VBegin        142
#define OP_ToText        143 /* same as TK_TO_TEXT                         */
#define OP_ToBlob        144 /* same as TK_TO_BLOB                         */
#define OP_ToNumeric     145 /* same as TK_TO_NUMERIC                      */
#define OP_ToInt         146 /* same as TK_TO_INT                          */
#define OP_ToReal        147 /* same as TK_TO_REAL                         */
#define OP_VCreate       148
#define OP_VDestroy      149
#define OP_VOpen         150
#define OP_VColumn       151 /* synopsis: r[P3]=vcolumn(P2)                */
#define OP_VNext         152
#define OP_VRename       153
#define OP_Pagecount     154
#define OP_MaxPgcnt      155
#define OP_Init          156 /* synopsis: Start at P2                      */
#define OP_Noop          157
#define OP_Explain       158


/* Properties such as "out2" or "jump" that are specified in
** comments following the "case" for each opcode in the vdbe.c
** are encoded into bitvectors as follows:
*/
#define OPFLG_JUMP            0x0001  /* jump:  P2 holds jmp target */
#define OPFLG_OUT2_PRERELEASE 0x0002  /* out2-prerelease: */
#define OPFLG_IN1             0x0004  /* in1:   P1 is an input */
#define OPFLG_IN2             0x0008  /* in2:   P2 is an input */
#define OPFLG_IN3             0x0010  /* in3:   P3 is an input */
#define OPFLG_OUT2            0x0020  /* out2:  P2 is an output */
#define OPFLG_OUT3            0x0040  /* out3:  P3 is an output */
#define OPFLG_INITIALIZER {\
/*   0 */ 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x01, 0x01,\
/*   8 */ 0x01, 0x01, 0x00, 0x00, 0x02, 0x00, 0x01, 0x00,\
/*  16 */ 0x01, 0x01, 0x04, 0x24, 0x01, 0x04, 0x05, 0x10,\
/*  24 */ 0x00, 0x02, 0x02, 0x02, 0x02, 0x00, 0x02, 0x02,\
/*  32 */ 0x00, 0x00, 0x20, 0x00, 0x00, 0x04, 0x05, 0x04,\
/*  40 */ 0x00, 0x00, 0x01, 0x01, 0x05, 0x05, 0x00, 0x00,\
/*  48 */ 0x00, 0x02, 0x02, 0x10, 0x00, 0x00, 0x00, 0x00,\
/*  56 */ 0x00, 0x00, 0x00, 0x00, 0x11, 0x11, 0x11, 0x11,\
/*  64 */ 0x08, 0x11, 0x11, 0x11, 0x11, 0x02, 0x02, 0x4c,\
/*  72 */ 0x4c, 0x00, 0x00, 0x00, 0x05, 0x05, 0x15, 0x15,\
/*  80 */ 0x15, 0x15, 0x15, 0x15, 0x00, 0x4c, 0x4c, 0x4c,\
/*  88 */ 0x4c, 0x4c, 0x4c, 0x4c, 0x4c, 0x4c, 0x4c, 0x00,\
/*  96 */ 0x24, 0x02, 0x00, 0x00, 0x00, 0x02, 0x00, 0x01,\
/* 104 */ 0x01, 0x01, 0x01, 0x08, 0x08, 0x00, 0x02, 0x01,\
/* 112 */ 0x01, 0x01, 0x01, 0x02, 0x00, 0x00, 0x02, 0x02,\
/* 120 */ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x0c, 0x45,\
/* 128 */ 0x15, 0x01, 0x02, 0x00, 0x01, 0x02, 0x08, 0x05,\
/* 136 */ 0x05, 0x05, 0x00, 0x01, 0x00, 0x00, 0x00, 0x04,\
/* 144 */ 0x04, 0x04, 0x04, 0x04, 0x00, 0x00, 0x00, 0x00,\
/* 152 */ 0x01, 0x00, 0x02, 0x02, 0x01, 0x00, 0x00,}

/************** End of opcodes.h *********************************************/
/************** Continuing where we left off in vdbe.h ***********************/

/*
** Prototypes for the VDBE interface.  See comments on the implementation
** for a description of what each of these routines does.

*/
SQLITE_PRIVATE void sqlite3PCacheBufferSetup(void *, int sz, int n);

/* Create a new pager cache.
** Under memory stress, invoke xStress to try to make pages clean.
** Only clean and unpinned pages can be reclaimed.
*/
SQLITE_PRIVATE void sqlite3PcacheOpen(
  int szPage,                    /* Size of every page */
  int szExtra,                   /* Extra space associated with each page */
  int bPurgeable,                /* True if pages are on backing store */
  int (*xStress)(void*, PgHdr*), /* Call to try to make pages clean */
  void *pStress,                 /* Argument to xStress */
  PCache *pToInit                /* Preallocated space for the PCache */
);

/* Modify the page-size after the cache has been created. */
SQLITE_PRIVATE void sqlite3PcacheSetPageSize(PCache *, int);

/* Return the size in bytes of a PCache object.  Used to preallocate
** storage space.
*/
SQLITE_PRIVATE int sqlite3PcacheSize(void);

/* One release per successful fetch.  Page is pinned until released.
** Reference counted. 
*/

SQLITE_PRIVATE int sqlite3PcacheFetch(PCache*, Pgno, int createFlag, PgHdr**);

SQLITE_PRIVATE void sqlite3PcacheRelease(PgHdr*);

SQLITE_PRIVATE void sqlite3PcacheDrop(PgHdr*);         /* Remove page from cache */
SQLITE_PRIVATE void sqlite3PcacheMakeDirty(PgHdr*);    /* Make sure page is marked dirty */
SQLITE_PRIVATE void sqlite3PcacheMakeClean(PgHdr*);    /* Mark a single page as clean */
SQLITE_PRIVATE void sqlite3PcacheCleanAll(PCache*);    /* Mark all dirty list pages as clean */

#define DB_UnresetViews    0x0002  /* Some views have defined column names */
#define DB_Empty           0x0004  /* The file is empty (length 0 bytes) */

/*
** The number of different kinds of things that can be limited
** using the sqlite3_limit() interface.
*/
#define SQLITE_N_LIMIT (SQLITE_LIMIT_TRIGGER_DEPTH+1)

/*
** Lookaside malloc is a set of fixed-size buffers that can be used
** to satisfy small transient memory allocation requests for objects
** associated with a particular database connection.  The use of
** lookaside malloc provides a significant performance enhancement
** (approx 10%) by avoiding numerous malloc/free requests while parsing

  u8 vtabOnConflict;            /* Value to return for s3_vtab_on_conflict() */
  u8 isTransactionSavepoint;    /* True if the outermost savepoint is a TS */
  int nextPagesize;             /* Pagesize after VACUUM if >0 */
  u32 magic;                    /* Magic number for detect library misuse */
  int nChange;                  /* Value returned by sqlite3_changes() */
  int nTotalChange;             /* Value returned by sqlite3_total_changes() */
  int aLimit[SQLITE_N_LIMIT];   /* Limits */

  struct sqlite3InitInfo {      /* Information used during initialization */
    int newTnum;                /* Rootpage of table being initialized */
    u8 iDb;                     /* Which db file is being initialized */
    u8 busy;                    /* TRUE if currently initializing */
    u8 orphanTrigger;           /* Last statement is orphaned TEMP trigger */
  } init;
  int nVdbeActive;              /* Number of VDBEs currently running */

** The r1 and r2 member variables are only used by the optimized comparison
** functions vdbeRecordCompareInt() and vdbeRecordCompareString().
*/
struct UnpackedRecord {
  KeyInfo *pKeyInfo;  /* Collation and sort-order information */
  u16 nField;         /* Number of entries in apMem[] */
  i8 default_rc;      /* Comparison result if keys are equal */
  u8 isCorrupt;       /* Corruption detected by xRecordCompare() */
  Mem *aMem;          /* Values */
  int r1;             /* Value to return if (lhs > rhs) */
  int r2;             /* Value to return if (rhs < lhs) */
};


/*

SQLITE_PRIVATE LogEst sqlite3LogEstFromDouble(double);
#endif
SQLITE_PRIVATE u64 sqlite3LogEstToInt(LogEst);

/*
** Routines to read and write variable-length integers.  These used to
** be defined locally, but now we use the varint routines in the util.c
** file.  Code should use the MACRO forms below, as the Varint32 versions
** are coded to assume the single byte case is already handled (which 
** the MACRO form does).
*/
SQLITE_PRIVATE int sqlite3PutVarint(unsigned char*, u64);
SQLITE_PRIVATE int sqlite3PutVarint32(unsigned char*, u32);
SQLITE_PRIVATE u8 sqlite3GetVarint(const unsigned char *, u64 *);
SQLITE_PRIVATE u8 sqlite3GetVarint32(const unsigned char *, u32 *);
SQLITE_PRIVATE int sqlite3VarintLen(u64 v);

/*
** The header of a record consists of a sequence variable-length integers.
** These integers are almost always small and are encoded as a single byte.
** The following macros take advantage this fact to provide a fast encode
** and decode of the integers in a record header.  It is faster for the common
** case where the integer is a single byte.  It is a little slower when the
** integer is two or more bytes.  But overall it is faster.
**
** The following expressions are equivalent:
**
**     x = sqlite3GetVarint32( A, &B );
**     x = sqlite3PutVarint32( A, B );
**
**     x = getVarint32( A, B );
**     x = putVarint32( A, B );
**
*/
#define getVarint32(A,B)  \
  (u8)((*(A)<(u8)0x80)?((B)=(u32)*(A)),1:sqlite3GetVarint32((A),(u32 *)&(B)))
#define putVarint32(A,B)  \
  (u8)(((u32)(B)<(u32)0x80)?(*(A)=(unsigned char)(B)),1:\
  sqlite3PutVarint32((A),(B)))
#define getVarint    sqlite3GetVarint
#define putVarint    sqlite3PutVarint


SQLITE_PRIVATE const char *sqlite3IndexAffinityStr(Vdbe *, Index *);
SQLITE_PRIVATE void sqlite3TableAffinity(Vdbe*, Table*, int);
SQLITE_PRIVATE char sqlite3CompareAffinity(Expr *pExpr, char aff2);
SQLITE_PRIVATE int sqlite3IndexAffinityOk(Expr *pExpr, char idx_affinity);
SQLITE_PRIVATE char sqlite3ExprAffinity(Expr *pExpr);
SQLITE_PRIVATE int sqlite3Atoi64(const char*, i64*, int, u8);
SQLITE_PRIVATE int sqlite3DecOrHexToI64(const char*, i64*);

SQLITE_PRIVATE void sqlite3Error(sqlite3*, int, const char*,...);
SQLITE_PRIVATE void *sqlite3HexToBlob(sqlite3*, const char *z, int n);
SQLITE_PRIVATE u8 sqlite3HexToInt(int h);
SQLITE_PRIVATE int sqlite3TwoPartName(Parse *, Token *, Token *, Token **);

#if defined(SQLITE_TEST) 
SQLITE_PRIVATE const char *sqlite3ErrName(int);
#endif

#endif
#define MEMTYPE_HEAP       0x01  /* General heap allocations */
#define MEMTYPE_LOOKASIDE  0x02  /* Might have been lookaside memory */
#define MEMTYPE_SCRATCH    0x04  /* Scratch allocations */
#define MEMTYPE_PCACHE     0x08  /* Page cache allocations */
#define MEMTYPE_DB         0x10  /* Uses sqlite3DbMalloc, not sqlite_malloc */









#endif /* _SQLITEINT_H_ */

/************** End of sqliteInt.h *******************************************/
/************** Begin file global.c ******************************************/
/*
** 2008 June 13
**

** But this file is the only place where the internal details of this
** structure are known.
**
** This structure is defined inside of vdbeInt.h because it uses substructures
** (Mem) which are only defined there.
*/
struct sqlite3_context {

  FuncDef *pFunc;       /* Pointer to function information.  MUST BE FIRST */
  Mem s;                /* The return value is stored here */
  Mem *pMem;            /* Memory cell used to store aggregate context */
  CollSeq *pColl;       /* Collating sequence */
  Vdbe *pVdbe;          /* The VM that owns this context */
  int iOp;              /* Instruction number of OP_Function */
  int isError;          /* Error code returned by the function. */
  u8 skipFlag;          /* Skip skip accumulator loading if true */
  u8 fErrorOrAux;       /* isError!=0 or pVdbe->pAuxData modified */

#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*);
SQLITE_PRIVATE double sqlite3VdbeRealValue(Mem*);
SQLITE_PRIVATE void sqlite3VdbeIntegerAffinity(Mem*);
SQLITE_PRIVATE int sqlite3VdbeMemRealify(Mem*);
SQLITE_PRIVATE int sqlite3VdbeMemNumerify(Mem*);

SQLITE_PRIVATE int sqlite3VdbeMemFromBtree(BtCursor*,u32,u32,int,Mem*);
SQLITE_PRIVATE void sqlite3VdbeMemRelease(Mem *p);
SQLITE_PRIVATE void sqlite3VdbeMemReleaseExternal(Mem *p);
#define VdbeMemDynamic(X)  \
  (((X)->flags&(MEM_Agg|MEM_Dyn|MEM_RowSet|MEM_Frame))!=0)
#define VdbeMemRelease(X)  \
  if( VdbeMemDynamic(X) ) sqlite3VdbeMemReleaseExternal(X);
SQLITE_PRIVATE int sqlite3VdbeMemFinalize(Mem*, FuncDef*);
SQLITE_PRIVATE const char *sqlite3OpcodeName(int);
SQLITE_PRIVATE int sqlite3VdbeMemGrow(Mem *pMem, int n, int preserve);
SQLITE_PRIVATE int sqlite3VdbeCloseStatement(Vdbe *, int);
SQLITE_PRIVATE void sqlite3VdbeFrameDelete(VdbeFrame*);
SQLITE_PRIVATE int sqlite3VdbeFrameRestore(VdbeFrame *);
SQLITE_PRIVATE int sqlite3VdbeTransferError(Vdbe *p);

SQLITE_PRIVATE int sqlite3VdbeSorterInit(sqlite3 *, VdbeCursor *);
SQLITE_PRIVATE void sqlite3VdbeSorterReset(sqlite3 *, VdbeSorter *);
SQLITE_PRIVATE void sqlite3VdbeSorterClose(sqlite3 *, VdbeCursor *);
SQLITE_PRIVATE int sqlite3VdbeSorterRowkey(const VdbeCursor *, Mem *);
SQLITE_PRIVATE int sqlite3VdbeSorterNext(sqlite3 *, const VdbeCursor *, int *);
SQLITE_PRIVATE int sqlite3VdbeSorterRewind(sqlite3 *, const VdbeCursor *, int *);
SQLITE_PRIVATE int sqlite3VdbeSorterWrite(sqlite3 *, const VdbeCursor *, Mem *);
SQLITE_PRIVATE int sqlite3VdbeSorterCompare(const VdbeCursor *, Mem *, int, int *);

#if !defined(SQLITE_OMIT_SHARED_CACHE) && SQLITE_THREADSAFE>0
SQLITE_PRIVATE   void sqlite3VdbeEnter(Vdbe*);
SQLITE_PRIVATE   void sqlite3VdbeLeave(Vdbe*);
#else
# define sqlite3VdbeEnter(X)

** Determine if we are dealing with WinRT, which provides only a subset of
** the full Win32 API.
*/
#if !defined(SQLITE_OS_WINRT)
# define SQLITE_OS_WINRT 0
#endif











#endif /* _OS_WIN_H_ */

/************** End of os_win.h **********************************************/
/************** Continuing where we left off in mutex_w32.c ******************/
#endif

/*

static int winMutex_isInit = 0;
static int winMutex_isNt = -1; /* <0 means "need to query" */

/* As the winMutexInit() and winMutexEnd() functions are called as part
** of the sqlite3_initialize() and sqlite3_shutdown() processing, the
** "interlocked" magic used here is probably not strictly necessary.
*/
static LONG volatile winMutex_lock = 0;

SQLITE_API int sqlite3_win32_is_nt(void); /* os_win.c */
SQLITE_API void sqlite3_win32_sleep(DWORD milliseconds); /* os_win.c */

static int winMutexInit(void){
  /* The first to increment to 1 does actual initialization */
  if( InterlockedCompareExchange(&winMutex_lock, 1, 0)==0 ){

** embedded processor.
*/
SQLITE_PRIVATE void *sqlite3ScratchMalloc(int n){
  void *p;
  assert( n>0 );

  sqlite3_mutex_enter(mem0.mutex);

  if( mem0.nScratchFree && sqlite3GlobalConfig.szScratch>=n ){
    p = mem0.pScratchFree;
    mem0.pScratchFree = mem0.pScratchFree->pNext;
    mem0.nScratchFree--;
    sqlite3StatusAdd(SQLITE_STATUS_SCRATCH_USED, 1);
    sqlite3StatusSet(SQLITE_STATUS_SCRATCH_SIZE, n);
    sqlite3_mutex_leave(mem0.mutex);
  }else{


    if( sqlite3GlobalConfig.bMemstat ){
      sqlite3StatusSet(SQLITE_STATUS_SCRATCH_SIZE, n);
      n = mallocWithAlarm(n, &p);
      if( p ) sqlite3StatusAdd(SQLITE_STATUS_SCRATCH_OVERFLOW, n);
      sqlite3_mutex_leave(mem0.mutex);
    }else{
      sqlite3_mutex_leave(mem0.mutex);
      p = sqlite3GlobalConfig.m.xMalloc(n);
    }
    sqlite3MemdebugSetType(p, MEMTYPE_SCRATCH);
  }
  assert( sqlite3_mutex_notheld(mem0.mutex) );


#if SQLITE_THREADSAFE==0 && !defined(NDEBUG)

    sqlite3StatusAdd(SQLITE_STATUS_MALLOC_COUNT, -1);
    sqlite3GlobalConfig.m.xFree(p);
    sqlite3_mutex_leave(mem0.mutex);
  }else{
    sqlite3GlobalConfig.m.xFree(p);
  }
}









/*
** Free memory that might be associated with a particular database
** connection.
*/
SQLITE_PRIVATE void sqlite3DbFree(sqlite3 *db, void *p){
  assert( db==0 || sqlite3_mutex_held(db->mutex) );
  if( p==0 ) return;
  if( db ){
    if( db->pnBytesFreed ){
      *db->pnBytesFreed += sqlite3DbMallocSize(db, p);
      return;
    }
    if( isLookaside(db, p) ){
      LookasideSlot *pBuf = (LookasideSlot*)p;
#if SQLITE_DEBUG
      /* Trash all content in the buffer being freed */
      memset(p, 0xaa, db->lookaside.sz);

  va_start(ap, zFormat);
  z = sqlite3VMPrintf(db, zFormat, ap);
  va_end(ap);
  sqlite3DbFree(db, *pz);
  *pz = z;
}










/*
** This function must be called before exiting any API function (i.e. 
** returning control to the user) that has called sqlite3_malloc or
** sqlite3_realloc.
**
** The returned value is normally a copy of the second argument to this
** function. However, if a malloc() failure has occurred since the previous
** invocation SQLITE_NOMEM is returned instead. 
**
** If the first argument, db, is not NULL and a malloc() error has occurred,
** then the connection error-code (the value returned by sqlite3_errcode())
** is set to SQLITE_NOMEM.
*/
SQLITE_PRIVATE int sqlite3ApiExit(sqlite3* db, int rc){
  /* If the db handle is not NULL, then we must hold the connection handle
  ** mutex here. Otherwise the read (and possible write) of db->mallocFailed 
  ** is unsafe, as is the call to sqlite3Error().
  */
  assert( !db || sqlite3_mutex_held(db->mutex) );

  if( db && (db->mallocFailed || rc==SQLITE_IOERR_NOMEM) ){
    sqlite3Error(db, SQLITE_NOMEM, 0);
    db->mallocFailed = 0;
    rc = SQLITE_NOMEM;
  }
  return rc & (db ? db->errMask : 0xff);
}

/************** End of malloc.c **********************************************/
/************** Begin file printf.c ******************************************/
/*
** The "printf" code that follows dates from the 1980's.  It is in
** the public domain.  The original comments are included here for

** The StrAccum "p" is not large enough to accept N new bytes of z[].
** So enlarge if first, then do the append.
**
** This is a helper routine to sqlite3StrAccumAppend() that does special-case
** work (enlarging the buffer) using tail recursion, so that the
** sqlite3StrAccumAppend() routine can use fast calling semantics.
*/
static void enlargeAndAppend(StrAccum *p, const char *z, int N){
  N = sqlite3StrAccumEnlarge(p, N);
  if( N>0 ){
    memcpy(&p->zText[p->nChar], z, N);
    p->nChar += N;
  }
}

/*
** Append N bytes of text from z to the StrAccum object.  Increase the
** size of the memory allocation for StrAccum if necessary.
*/
SQLITE_PRIVATE void sqlite3StrAccumAppend(StrAccum *p, const char *z, int N){
  assert( z!=0 );
  assert( p->zText!=0 || p->nChar==0 || p->accError );
  assert( N>=0 );
  assert( p->accError==0 || p->nAlloc==0 );
  if( p->nChar+N >= p->nAlloc ){
    enlargeAndAppend(p,z,N);
    return;
  }
  assert( p->zText );
  memcpy(&p->zText[p->nChar], z, N);
  p->nChar += N;


}

/*
** Append the complete text of zero-terminated string z[] to the p string.
*/
SQLITE_PRIVATE void sqlite3StrAccumAppendAll(StrAccum *p, const char *z){
  sqlite3StrAccumAppend(p, z, sqlite3Strlen30(z));

    &GLOBAL(struct sqlite3PrngType, sqlite3SavedPrng),
    sizeof(sqlite3Prng)
  );
}
#endif /* SQLITE_OMIT_BUILTIN_TEST */

/************** End of random.c **********************************************/








































































































































































































































































/************** Begin file utf.c *********************************************/
/*
** 2004 April 13
**
** The author disclaims copyright to this source code.  In place of
** a legal notice, here is a blessing:
**

#ifndef SQLITE_OMIT_UTF16
/*
** This routine transforms the internal text encoding used by pMem to
** desiredEnc. It is an error if the string is already of the desired
** encoding, or if *pMem does not contain a string value.
*/
SQLITE_PRIVATE int sqlite3VdbeMemTranslate(Mem *pMem, u8 desiredEnc){
  int len;                    /* Maximum length of output string in bytes */
  unsigned char *zOut;                  /* Output buffer */
  unsigned char *zIn;                   /* Input iterator */
  unsigned char *zTerm;                 /* End of input */
  unsigned char *z;                     /* Output iterator */
  unsigned int c;

*/
SQLITE_PRIVATE int sqlite3Strlen30(const char *z){
  const char *z2 = z;
  if( z==0 ) return 0;
  while( *z2 ){ z2++; }
  return 0x3fffffff & (int)(z2 - z);
}










/*
** Set the most recent error code and error string for the sqlite
** handle "db". The error code is set to "err_code".
**
** If it is not NULL, string zFormat specifies the format of the
** error string in the style of the printf functions: The following

** zFormat and any string tokens that follow it are assumed to be
** encoded in UTF-8.
**
** To clear the most recent error for sqlite handle "db", sqlite3Error
** should be called with err_code set to SQLITE_OK and zFormat set
** to NULL.
*/
SQLITE_PRIVATE void sqlite3Error(sqlite3 *db, int err_code, const char *zFormat, ...){
  assert( db!=0 );
  db->errCode = err_code;


  if( zFormat && (db->pErr || (db->pErr = sqlite3ValueNew(db))!=0) ){
    char *z;
    va_list ap;
    va_start(ap, zFormat);
    z = sqlite3VMPrintf(db, zFormat, ap);
    va_end(ap);
    sqlite3ValueSetStr(db->pErr, -1, z, SQLITE_UTF8, SQLITE_DYNAMIC);
  }else if( db->pErr ){
    sqlite3ValueSetNull(db->pErr);
  }
}

/*
** Add an error message to pParse->zErrMsg and increment pParse->nErr.
** The following formatting characters are allowed:
**
**      %s      Insert a string
**      %z      A string that should be freed after use
**      %d      Insert an integer
**      %T      Insert a token
**      %S      Insert the first element of a SrcList
**
** This function should be used to report any error that occurs whilst
** 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);

** of bytes written is returned.
**
** A variable-length integer consists of the lower 7 bits of each byte
** for all bytes that have the 8th bit set and one byte with the 8th
** bit clear.  Except, if we get to the 9th byte, it stores the full
** 8 bits and is the last byte.
*/
SQLITE_PRIVATE int sqlite3PutVarint(unsigned char *p, u64 v){
  int i, j, n;
  u8 buf[10];
  if( v & (((u64)0xff000000)<<32) ){
    p[8] = (u8)v;
    v >>= 8;
    for(i=7; i>=0; i--){
      p[i] = (u8)((v & 0x7f) | 0x80);

  buf[0] &= 0x7f;
  assert( n<=9 );
  for(i=0, j=n-1; j>=0; j--, i++){
    p[i] = buf[j];
  }
  return n;
}

/*
** This routine is a faster version of sqlite3PutVarint() that only
** works for 32-bit positive integers and which is optimized for
** the common case of small integers.  A MACRO version, putVarint32,
** is provided which inlines the single-byte case.  All code should use
** the MACRO version as this function assumes the single-byte case has
** already been handled.
*/
SQLITE_PRIVATE int sqlite3PutVarint32(unsigned char *p, u32 v){
#ifndef putVarint32
  if( (v & ~0x7f)==0 ){
    p[0] = v;
    return 1;
  }
#endif
  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.
**

  }
  pH->count = 0;
}

/*
** The hashing function.
*/
static unsigned int strHash(const char *z, int nKey){
  unsigned int h = 0;
  assert( nKey>=0 );
  while( nKey > 0  ){
    h = (h<<3) ^ h ^ sqlite3UpperToLower[(unsigned char)*z++];
    nKey--;
  }
  return h;
}


/* Link pNew element into the hash table pH.  If pEntry!=0 then also
** insert pNew into the pEntry hash bucket.

  if( new_ht==0 ) return 0;
  sqlite3_free(pH->ht);
  pH->ht = new_ht;
  pH->htsize = new_size = sqlite3MallocSize(new_ht)/sizeof(struct _ht);
  memset(new_ht, 0, new_size*sizeof(struct _ht));
  for(elem=pH->first, pH->first=0; elem; elem = next_elem){
    unsigned int h = strHash(elem->pKey, elem->nKey) % new_size;
    next_elem = elem->next;
    insertElement(pH, &new_ht[h], elem);
  }
  return 1;
}

/* This function (for internal use only) locates an element in an
** hash table that matches the given key.  The hash for this key has
** already been computed and is passed as the 4th parameter.
*/
static HashElem *findElementGivenHash(
  const Hash *pH,     /* The pH to be searched */
  const char *pKey,   /* The key we are searching for */
  int nKey,           /* Bytes in key (not counting zero terminator) */
  unsigned int h      /* The hash for this key. */
){
  HashElem *elem;                /* Used to loop thru the element list */
  int count;                     /* Number of elements left to test */


  if( pH->ht ){
    struct _ht *pEntry = &pH->ht[h];


    elem = pEntry->chain;
    count = pEntry->count;
  }else{

    elem = pH->first;
    count = pH->count;
  }

  while( count-- && ALWAYS(elem) ){

    if( elem->nKey==nKey && sqlite3StrNICmp(elem->pKey,pKey,nKey)==0 ){ 
      return elem;
    }
    elem = elem->next;
  }
  return 0;
}

    assert( pH->first==0 );
    assert( pH->count==0 );
    sqlite3HashClear(pH);
  }
}

/* Attempt to locate an element of the hash table pH with a key
** that matches pKey,nKey.  Return the data for this element if it is
** found, or NULL if there is no match.
*/
SQLITE_PRIVATE void *sqlite3HashFind(const Hash *pH, const char *pKey, int nKey){
  HashElem *elem;    /* The element that matches key */
  unsigned int h;    /* A hash on key */

  assert( pH!=0 );
  assert( pKey!=0 );
  assert( nKey>=0 );
  if( pH->ht ){
    h = strHash(pKey, nKey) % pH->htsize;
  }else{
    h = 0;
  }
  elem = findElementGivenHash(pH, pKey, nKey, h);
  return elem ? elem->data : 0;
}

/* Insert an element into the hash table pH.  The key is pKey,nKey
** and the data is "data".
**
** If no element exists with a matching key, then a new
** element is created and NULL is returned.
**
** If another element already exists with the same key, then the
** new data replaces the old data and the old data is returned.
** The key is not copied in this instance.  If a malloc fails, then
** the new data is returned and the hash table is unchanged.
**
** If the "data" parameter to this function is NULL, then the
** element corresponding to "key" is removed from the hash table.
*/
SQLITE_PRIVATE void *sqlite3HashInsert(Hash *pH, const char *pKey, int nKey, void *data){
  unsigned int h;       /* the hash of the key modulo hash table size */
  HashElem *elem;       /* Used to loop thru the element list */
  HashElem *new_elem;   /* New element added to the pH */

  assert( pH!=0 );
  assert( pKey!=0 );
  assert( nKey>=0 );
  if( pH->htsize ){
    h = strHash(pKey, nKey) % pH->htsize;
  }else{
    h = 0;
  }
  elem = findElementGivenHash(pH,pKey,nKey,h);
  if( elem ){
    void *old_data = elem->data;
    if( data==0 ){
      removeElementGivenHash(pH,elem,h);
    }else{
      elem->data = data;
      elem->pKey = pKey;
      assert(nKey==elem->nKey);
    }
    return old_data;
  }
  if( data==0 ) return 0;
  new_elem = (HashElem*)sqlite3Malloc( sizeof(HashElem) );
  if( new_elem==0 ) return data;
  new_elem->pKey = pKey;
  new_elem->nKey = nKey;
  new_elem->data = data;
  pH->count++;
  if( pH->count>=10 && pH->count > 2*pH->htsize ){
    if( rehash(pH, pH->count*2) ){
      assert( pH->htsize>0 );
      h = strHash(pKey, nKey) % pH->htsize;
    }
  }
  if( pH->ht ){
    insertElement(pH, &pH->ht[h], new_elem);
  }else{
    insertElement(pH, 0, new_elem);
  }
  return 0;
}

/************** End of hash.c ************************************************/
/************** Begin file opcodes.c *****************************************/
/* Automatically generated.  Do not edit */
/* See the mkopcodec.awk script for details. */

     /*  33 */ "Copy"             OpHelp("r[P2@P3+1]=r[P1@P3+1]"),
     /*  34 */ "SCopy"            OpHelp("r[P2]=r[P1]"),
     /*  35 */ "ResultRow"        OpHelp("output=r[P1@P2]"),
     /*  36 */ "CollSeq"          OpHelp(""),
     /*  37 */ "AddImm"           OpHelp("r[P1]=r[P1]+P2"),
     /*  38 */ "MustBeInt"        OpHelp(""),
     /*  39 */ "RealAffinity"     OpHelp(""),

     /*  40 */ "Permutation"      OpHelp(""),
     /*  41 */ "Compare"          OpHelp("r[P1@P3] <-> r[P2@P3]"),
     /*  42 */ "Jump"             OpHelp(""),
     /*  43 */ "Once"             OpHelp(""),
     /*  44 */ "If"               OpHelp(""),
     /*  45 */ "IfNot"            OpHelp(""),
     /*  46 */ "Column"           OpHelp("r[P3]=PX"),
     /*  47 */ "Affinity"         OpHelp("affinity(r[P1@P2])"),
     /*  48 */ "MakeRecord"       OpHelp("r[P3]=mkrec(r[P1@P2])"),
     /*  49 */ "Count"            OpHelp("r[P2]=count()"),
     /*  50 */ "ReadCookie"       OpHelp(""),
     /*  51 */ "SetCookie"        OpHelp(""),
     /*  52 */ "ReopenIdx"        OpHelp("root=P2 iDb=P3"),
     /*  53 */ "OpenRead"         OpHelp("root=P2 iDb=P3"),
     /*  54 */ "OpenWrite"        OpHelp("root=P2 iDb=P3"),
     /*  55 */ "OpenAutoindex"    OpHelp("nColumn=P2"),
     /*  56 */ "OpenEphemeral"    OpHelp("nColumn=P2"),
     /*  57 */ "SorterOpen"       OpHelp(""),

     /*  58 */ "OpenPseudo"       OpHelp("P3 columns in r[P2]"),
     /*  59 */ "Close"            OpHelp(""),
     /*  60 */ "SeekLT"           OpHelp("key=r[P3@P4]"),
     /*  61 */ "SeekLE"           OpHelp("key=r[P3@P4]"),
     /*  62 */ "SeekGE"           OpHelp("key=r[P3@P4]"),
     /*  63 */ "SeekGT"           OpHelp("key=r[P3@P4]"),
     /*  64 */ "Seek"             OpHelp("intkey=r[P2]"),
     /*  65 */ "NoConflict"       OpHelp("key=r[P3@P4]"),
     /*  66 */ "NotFound"         OpHelp("key=r[P3@P4]"),
     /*  67 */ "Found"            OpHelp("key=r[P3@P4]"),
     /*  68 */ "NotExists"        OpHelp("intkey=r[P3]"),
     /*  69 */ "Sequence"         OpHelp("r[P2]=cursor[P1].ctr++"),
     /*  70 */ "NewRowid"         OpHelp("r[P2]=rowid"),
     /*  71 */ "Or"               OpHelp("r[P3]=(r[P1] || r[P2])"),
     /*  72 */ "And"              OpHelp("r[P3]=(r[P1] && r[P2])"),


     /*  73 */ "Insert"           OpHelp("intkey=r[P3] data=r[P2]"),
     /*  74 */ "InsertInt"        OpHelp("intkey=P3 data=r[P2]"),
     /*  75 */ "Delete"           OpHelp(""),
     /*  76 */ "IsNull"           OpHelp("if r[P1]==NULL goto P2"),
     /*  77 */ "NotNull"          OpHelp("if r[P1]!=NULL goto P2"),
     /*  78 */ "Ne"               OpHelp("if r[P1]!=r[P3] goto P2"),
     /*  79 */ "Eq"               OpHelp("if r[P1]==r[P3] goto P2"),
     /*  80 */ "Gt"               OpHelp("if r[P1]>r[P3] goto P2"),
     /*  81 */ "Le"               OpHelp("if r[P1]<=r[P3] goto P2"),
     /*  82 */ "Lt"               OpHelp("if r[P1]<r[P3] goto P2"),
     /*  83 */ "Ge"               OpHelp("if r[P1]>=r[P3] goto P2"),
     /*  84 */ "ResetCount"       OpHelp(""),
     /*  85 */ "BitAnd"           OpHelp("r[P3]=r[P1]&r[P2]"),
     /*  86 */ "BitOr"            OpHelp("r[P3]=r[P1]|r[P2]"),
     /*  87 */ "ShiftLeft"        OpHelp("r[P3]=r[P2]<<r[P1]"),
     /*  88 */ "ShiftRight"       OpHelp("r[P3]=r[P2]>>r[P1]"),
     /*  89 */ "Add"              OpHelp("r[P3]=r[P1]+r[P2]"),
     /*  90 */ "Subtract"         OpHelp("r[P3]=r[P2]-r[P1]"),
     /*  91 */ "Multiply"         OpHelp("r[P3]=r[P1]*r[P2]"),
     /*  92 */ "Divide"           OpHelp("r[P3]=r[P2]/r[P1]"),
     /*  93 */ "Remainder"        OpHelp("r[P3]=r[P2]%r[P1]"),
     /*  94 */ "Concat"           OpHelp("r[P3]=r[P2]+r[P1]"),
     /*  95 */ "SorterCompare"    OpHelp("if key(P1)!=trim(r[P3],P4) goto P2"),
     /*  96 */ "BitNot"           OpHelp("r[P1]= ~r[P1]"),
     /*  97 */ "String8"          OpHelp("r[P2]='P4'"),


     /*  98 */ "SorterData"       OpHelp("r[P2]=data"),
     /*  99 */ "RowKey"           OpHelp("r[P2]=key"),
     /* 100 */ "RowData"          OpHelp("r[P2]=data"),
     /* 101 */ "Rowid"            OpHelp("r[P2]=rowid"),
     /* 102 */ "NullRow"          OpHelp(""),
     /* 103 */ "Last"             OpHelp(""),
     /* 104 */ "SorterSort"       OpHelp(""),
     /* 105 */ "Sort"             OpHelp(""),
     /* 106 */ "Rewind"           OpHelp(""),
     /* 107 */ "SorterInsert"     OpHelp(""),
     /* 108 */ "IdxInsert"        OpHelp("key=r[P2]"),
     /* 109 */ "IdxDelete"        OpHelp("key=r[P2@P3]"),
     /* 110 */ "IdxRowid"         OpHelp("r[P2]=rowid"),
     /* 111 */ "IdxLE"            OpHelp("key=r[P3@P4]"),
     /* 112 */ "IdxGT"            OpHelp("key=r[P3@P4]"),
     /* 113 */ "IdxLT"            OpHelp("key=r[P3@P4]"),
     /* 114 */ "IdxGE"            OpHelp("key=r[P3@P4]"),
     /* 115 */ "Destroy"          OpHelp(""),
     /* 116 */ "Clear"            OpHelp(""),
     /* 117 */ "ResetSorter"      OpHelp(""),
     /* 118 */ "CreateIndex"      OpHelp("r[P2]=root iDb=P1"),
     /* 119 */ "CreateTable"      OpHelp("r[P2]=root iDb=P1"),
     /* 120 */ "ParseSchema"      OpHelp(""),
     /* 121 */ "LoadAnalysis"     OpHelp(""),
     /* 122 */ "DropTable"        OpHelp(""),
     /* 123 */ "DropIndex"        OpHelp(""),
     /* 124 */ "DropTrigger"      OpHelp(""),
     /* 125 */ "IntegrityCk"      OpHelp(""),
     /* 126 */ "RowSetAdd"        OpHelp("rowset(P1)=r[P2]"),
     /* 127 */ "RowSetRead"       OpHelp("r[P3]=rowset(P1)"),
     /* 128 */ "RowSetTest"       OpHelp("if r[P3] in rowset(P1) goto P2"),
     /* 129 */ "Program"          OpHelp(""),
     /* 130 */ "Param"            OpHelp(""),
     /* 131 */ "FkCounter"        OpHelp("fkctr[P1]+=P2"),
     /* 132 */ "FkIfZero"         OpHelp("if fkctr[P1]==0 goto P2"),
     /* 133 */ "Real"             OpHelp("r[P2]=P4"),


     /* 134 */ "MemMax"           OpHelp("r[P1]=max(r[P1],r[P2])"),
     /* 135 */ "IfPos"            OpHelp("if r[P1]>0 goto P2"),
     /* 136 */ "IfNeg"            OpHelp("r[P1]+=P3, if r[P1]<0 goto P2"),
     /* 137 */ "IfZero"           OpHelp("r[P1]+=P3, if r[P1]==0 goto P2"),
     /* 138 */ "AggFinal"         OpHelp("accum=r[P1] N=P2"),
     /* 139 */ "IncrVacuum"       OpHelp(""),
     /* 140 */ "Expire"           OpHelp(""),
     /* 141 */ "TableLock"        OpHelp("iDb=P1 root=P2 write=P3"),
     /* 142 */ "VBegin"           OpHelp(""),
     /* 143 */ "ToText"           OpHelp(""),
     /* 144 */ "ToBlob"           OpHelp(""),
     /* 145 */ "ToNumeric"        OpHelp(""),
     /* 146 */ "ToInt"            OpHelp(""),
     /* 147 */ "ToReal"           OpHelp(""),
     /* 148 */ "VCreate"          OpHelp(""),
     /* 149 */ "VDestroy"         OpHelp(""),
     /* 150 */ "VOpen"            OpHelp(""),
     /* 151 */ "VColumn"          OpHelp("r[P3]=vcolumn(P2)"),
     /* 152 */ "VNext"            OpHelp(""),
     /* 153 */ "VRename"          OpHelp(""),
     /* 154 */ "Pagecount"        OpHelp(""),
     /* 155 */ "MaxPgcnt"         OpHelp(""),
     /* 156 */ "Init"             OpHelp("Start at P2"),
     /* 157 */ "Noop"             OpHelp(""),
     /* 158 */ "Explain"          OpHelp(""),
  };
  return azName[i];
}
#endif

/************** End of opcodes.c *********************************************/
/************** Begin file os_unix.c *****************************************/

){
  int rc = SQLITE_OK;
  UNUSED_PARAMETER(NotUsed);
  SimulateIOError(return SQLITE_IOERR_DELETE);
  if( osUnlink(zPath)==(-1) ){
    if( errno==ENOENT
#if OS_VXWORKS
        || errno==0x380003
#endif
    ){
      rc = SQLITE_IOERR_DELETE_NOENT;
    }else{
      rc = unixLogError(SQLITE_IOERR_DELETE, "unlink", zPath);
    }
    return rc;

** 1:   Operating system is Win9x.
** 2:   Operating system is WinNT.
**
** In order to facilitate testing on a WinNT system, the test fixture
** can manually set this value to 1 to emulate Win98 behavior.
*/
#ifdef SQLITE_TEST
SQLITE_API LONG volatile sqlite3_os_type = 0;
#else
static LONG volatile sqlite3_os_type = 0;
#endif

#ifndef SYSCALL
#  define SYSCALL sqlite3_syscall_ptr
#endif

/*

#else
  { "WaitForSingleObject",     (SYSCALL)0,                       0 },
#endif

#define osWaitForSingleObject ((DWORD(WINAPI*)(HANDLE, \
        DWORD))aSyscall[63].pCurrent)

#if SQLITE_OS_WINRT
  { "WaitForSingleObjectEx",   (SYSCALL)WaitForSingleObjectEx,   0 },
#else
  { "WaitForSingleObjectEx",   (SYSCALL)0,                       0 },
#endif

#define osWaitForSingleObjectEx ((DWORD(WINAPI*)(HANDLE,DWORD, \
        BOOL))aSyscall[64].pCurrent)

#if SQLITE_OS_WINRT
  { "SetFilePointerEx",        (SYSCALL)SetFilePointerEx,        0 },
#else

#if defined(InterlockedCompareExchange)
  { "InterlockedCompareExchange", (SYSCALL)0,                    0 },

#define osInterlockedCompareExchange InterlockedCompareExchange
#else
  { "InterlockedCompareExchange", (SYSCALL)InterlockedCompareExchange, 0 },

#define osInterlockedCompareExchange ((LONG(WINAPI*)(LONG volatile*, \
        LONG,LONG))aSyscall[76].pCurrent)
#endif /* defined(InterlockedCompareExchange) */

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

/*
** This is the xSetSystemCall() method of sqlite3_vfs for all of the
** "win32" VFSes.  Return SQLITE_OK opon successfully updating the

  }
  assert( sleepObj!=NULL );
  osWaitForSingleObjectEx(sleepObj, milliseconds, FALSE);
#else
  osSleep(milliseconds);
#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

  for(p=pCache->pDirtyTail; p!=pCache->pSynced; p=p->pDirtyPrev){
    assert( p->nRef || (p->flags&PGHDR_NEED_SYNC) );
  }
  return (p==0 || p->nRef || (p->flags&PGHDR_NEED_SYNC)==0);
}
#endif /* !NDEBUG && SQLITE_ENABLE_EXPENSIVE_ASSERT */






/*


** Remove page pPage from the list of dirty pages.

*/
static void pcacheRemoveFromDirtyList(PgHdr *pPage){
  PCache *p = pPage->pCache;


  assert( pPage->pDirtyNext || pPage==p->pDirtyTail );
  assert( pPage->pDirtyPrev || pPage==p->pDirty );

  /* Update the PCache1.pSynced variable if necessary. */
  if( p->pSynced==pPage ){
    PgHdr *pSynced = pPage->pDirtyPrev;
    while( pSynced && (pSynced->flags&PGHDR_NEED_SYNC) ){
      pSynced = pSynced->pDirtyPrev;
    }
    p->pSynced = pSynced;
  }

  if( pPage->pDirtyNext ){
    pPage->pDirtyNext->pDirtyPrev = pPage->pDirtyPrev;
  }else{
    assert( pPage==p->pDirtyTail );
    p->pDirtyTail = pPage->pDirtyPrev;
  }
  if( pPage->pDirtyPrev ){
    pPage->pDirtyPrev->pDirtyNext = pPage->pDirtyNext;
  }else{
    assert( pPage==p->pDirty );
    p->pDirty = pPage->pDirtyNext;
    if( p->pDirty==0 && p->bPurgeable ){
      assert( p->eCreate==1 );
      p->eCreate = 2;
    }
  }
  pPage->pDirtyNext = 0;
  pPage->pDirtyPrev = 0;

  expensive_assert( pcacheCheckSynced(p) );
}

/*
** Add page pPage to the head of the dirty list (PCache1.pDirty is set to
** pPage).
*/
static void pcacheAddToDirtyList(PgHdr *pPage){
  PCache *p = pPage->pCache;

  assert( pPage->pDirtyNext==0 && pPage->pDirtyPrev==0 && p->pDirty!=pPage );

  pPage->pDirtyNext = p->pDirty;
  if( pPage->pDirtyNext ){
    assert( pPage->pDirtyNext->pDirtyPrev==0 );
    pPage->pDirtyNext->pDirtyPrev = pPage;
  }else if( p->bPurgeable ){
    assert( p->eCreate==2 );
    p->eCreate = 1;
  }
  p->pDirty = pPage;
  if( !p->pDirtyTail ){
    p->pDirtyTail = pPage;
  }
  if( !p->pSynced && 0==(pPage->flags&PGHDR_NEED_SYNC) ){
    p->pSynced = pPage;
  }
  expensive_assert( pcacheCheckSynced(p) );

}

/*
** Wrapper around the pluggable caches xUnpin method. If the cache is
** being used for an in-memory database, this function is a no-op.
*/
static void pcacheUnpin(PgHdr *p){
  PCache *pCache = p->pCache;
  if( pCache->bPurgeable ){
    if( p->pgno==1 ){
      pCache->pPage1 = 0;
    }
    sqlite3GlobalConfig.pcache2.xUnpin(pCache->pCache, p->pPage, 0);











  }
}

/*************************************************** General Interfaces ******
**
** Initialize and shutdown the page cache subsystem. Neither of these 
** functions are threadsafe.

/*
** Create a new PCache object. Storage space to hold the object
** has already been allocated and is passed in as the p pointer. 
** The caller discovers how much space needs to be allocated by 
** calling sqlite3PcacheSize().
*/
SQLITE_PRIVATE void sqlite3PcacheOpen(
  int szPage,                  /* Size of every page */
  int szExtra,                 /* Extra space associated with each page */
  int bPurgeable,              /* True if pages are on backing store */
  int (*xStress)(void*,PgHdr*),/* Call to try to make pages clean */
  void *pStress,               /* Argument to xStress */
  PCache *p                    /* Preallocated space for the PCache */
){
  memset(p, 0, sizeof(PCache));
  p->szPage = szPage;
  p->szExtra = szExtra;
  p->bPurgeable = bPurgeable;
  p->eCreate = 2;
  p->xStress = xStress;
  p->pStress = pStress;
  p->szCache = 100;

}

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







  if( pCache->pCache ){
    sqlite3GlobalConfig.pcache2.xDestroy(pCache->pCache);

    pCache->pCache = 0;
    pCache->pPage1 = 0;
  }
  pCache->szPage = szPage;
}

/*
** Compute the number of pages of cache requested.
*/
static int numberOfCachePages(PCache *p){
  if( p->szCache>=0 ){
    return p->szCache;
  }else{
    return (int)((-1024*(i64)p->szCache)/(p->szPage+p->szExtra));
  }
}

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





















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

  assert( pCache!=0 );

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

  /* If the pluggable cache (sqlite3_pcache*) has not been allocated,
  ** allocate it now.
  */
  if( !pCache->pCache ){
    sqlite3_pcache *p;
    if( !createFlag ){
      *ppPage = 0;
      return SQLITE_OK;
    }
    p = sqlite3GlobalConfig.pcache2.xCreate(
        pCache->szPage, pCache->szExtra + sizeof(PgHdr), pCache->bPurgeable
    );
    if( !p ){
      return SQLITE_NOMEM;
    }
    sqlite3GlobalConfig.pcache2.xCachesize(p, numberOfCachePages(pCache));
    pCache->pCache = p;
  }

  /* eCreate defines what to do if the page does not exist.
  **    0     Do not allocate a new page.  (createFlag==0)
  **    1     Allocate a new page if doing so is inexpensive.
  **          (createFlag==1 AND bPurgeable AND pDirty)
  **    2     Allocate a new page even it doing so is difficult.
  **          (createFlag==1 AND !(bPurgeable AND pDirty)
  */
  eCreate = createFlag==0 ? 0 : pCache->eCreate;


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

  if( !pPage && eCreate==1 ){
















    PgHdr *pPg;



    /* Find a dirty page to write-out and recycle. First try to find a 
    ** page that does not require a journal-sync (one with PGHDR_NEED_SYNC
    ** cleared), but if that is not possible settle for any other 
    ** 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;
#ifdef SQLITE_LOG_CACHE_SPILL
      sqlite3_log(SQLITE_FULL, 
                  "spill page %d making room for %d - cache used: %d/%d",
                  pPg->pgno, pgno,
                  sqlite3GlobalConfig.pcache.xPagecount(pCache->pCache),
                  numberOfCachePages(pCache));
#endif
      rc = pCache->xStress(pCache->pStress, pPg);
      if( rc!=SQLITE_OK && rc!=SQLITE_BUSY ){
        return rc;
      }
    }

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

  }
















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

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

    }
    assert( pPgHdr->pCache==pCache );











    assert( pPgHdr->pgno==pgno );
    assert( pPgHdr->pData==pPage->pBuf );


    assert( pPgHdr->pExtra==(void *)&pPgHdr[1] );



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

/*
** Decrement the reference count on a page. If the page is clean and the
** reference count drops to 0, then it is made elible for recycling.
*/
SQLITE_PRIVATE void sqlite3PcacheRelease(PgHdr *p){
  assert( p->nRef>0 );
  p->nRef--;
  if( p->nRef==0 ){
    PCache *pCache = p->pCache;
    pCache->nRef--;
    if( (p->flags&PGHDR_DIRTY)==0 ){
      pcacheUnpin(p);
    }else{
      /* Move the page to the head of the dirty list. */
      pcacheRemoveFromDirtyList(p);
      pcacheAddToDirtyList(p);
    }
  }
}

/*
** Increase the reference count of a supplied page by 1.
*/
SQLITE_PRIVATE void sqlite3PcacheRef(PgHdr *p){
  assert(p->nRef>0);
  p->nRef++;
}

/*
** Drop a page from the cache. There must be exactly one reference to the
** page. This function deletes that reference, so after it returns the
** page pointed to by p is invalid.
*/
SQLITE_PRIVATE void sqlite3PcacheDrop(PgHdr *p){
  PCache *pCache;
  assert( p->nRef==1 );
  if( p->flags&PGHDR_DIRTY ){
    pcacheRemoveFromDirtyList(p);
  }
  pCache = p->pCache;
  pCache->nRef--;
  if( p->pgno==1 ){
    pCache->pPage1 = 0;
  }
  sqlite3GlobalConfig.pcache2.xUnpin(pCache->pCache, p->pPage, 1);
}

/*
** Make sure the page is marked as dirty. If it isn't dirty already,
** make it so.
*/
SQLITE_PRIVATE void sqlite3PcacheMakeDirty(PgHdr *p){
  p->flags &= ~PGHDR_DONT_WRITE;
  assert( p->nRef>0 );
  if( 0==(p->flags & PGHDR_DIRTY) ){
    p->flags |= PGHDR_DIRTY;
    pcacheAddToDirtyList( p);
  }
}

/*
** Make sure the page is marked as clean. If it isn't clean already,
** make it so.
*/
SQLITE_PRIVATE void sqlite3PcacheMakeClean(PgHdr *p){
  if( (p->flags & PGHDR_DIRTY) ){
    pcacheRemoveFromDirtyList(p);
    p->flags &= ~(PGHDR_DIRTY|PGHDR_NEED_SYNC);
    if( p->nRef==0 ){
      pcacheUnpin(p);
    }
  }
}

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

/*
** Drop every cache entry whose page number is greater than "pgno". The
** caller must ensure that there are no outstanding references to any pages
** other than page 1 with a page number greater than pgno.

  }
}

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

/* 
** Discard the contents of the cache.
*/
SQLITE_PRIVATE void sqlite3PcacheClear(PCache *pCache){
  sqlite3PcacheTruncate(pCache, 0);

  return p->nRef;
}

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

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

/*
** Set the suggested cache-size value.
*/
SQLITE_PRIVATE void sqlite3PcacheSetCachesize(PCache *pCache, int mxPage){

  pCache->szCache = mxPage;
  if( pCache->pCache ){
    sqlite3GlobalConfig.pcache2.xCachesize(pCache->pCache,
                                           numberOfCachePages(pCache));
  }
}

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

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

/*
** This function is used to resize the hash table used by the cache passed
** as the first argument.
**
** The PCache mutex must be held when this function is called.
*/
static int pcache1ResizeHash(PCache1 *p){
  PgHdr1 **apNew;
  unsigned int nNew;
  unsigned int i;

  assert( sqlite3_mutex_held(p->pGroup->mutex) );

  nNew = p->nHash*2;

        apNew[h] = pPage;
      }
    }
    sqlite3_free(p->apHash);
    p->apHash = apNew;
    p->nHash = nNew;
  }

  return (p->apHash ? SQLITE_OK : SQLITE_NOMEM);
}

/*
** This function is used internally to remove the page pPage from the 
** PGroup LRU list, if is part of it. If pPage is not part of the PGroup
** LRU list, then this function is a no-op.
**

*/
static void pcache1Shutdown(void *NotUsed){
  UNUSED_PARAMETER(NotUsed);
  assert( pcache1.isInit!=0 );
  memset(&pcache1, 0, sizeof(pcache1));
}




/*
** Implementation of the sqlite3_pcache.xCreate method.
**
** Allocate a new cache.
*/
static sqlite3_pcache *pcache1Create(int szPage, int szExtra, int bPurgeable){
  PCache1 *pCache;      /* The newly created page cache */

    }else{
      pGroup = &pcache1.grp;
    }
    pCache->pGroup = pGroup;
    pCache->szPage = szPage;
    pCache->szExtra = szExtra;
    pCache->bPurgeable = (bPurgeable ? 1 : 0);


    if( bPurgeable ){
      pCache->nMin = 10;
      pcache1EnterMutex(pGroup);
      pGroup->nMinPage += pCache->nMin;
      pGroup->mxPinned = pGroup->nMaxPage + 10 - pGroup->nMinPage;

      pcache1LeaveMutex(pGroup);



    }
  }
  return (sqlite3_pcache *)pCache;
}

/*
** Implementation of the sqlite3_pcache.xCachesize method. 

  PCache1 *pCache = (PCache1*)p;
  pcache1EnterMutex(pCache->pGroup);
  n = pCache->nPage;
  pcache1LeaveMutex(pCache->pGroup);
  return n;
}


























































































/*
** Implementation of the sqlite3_pcache.xFetch method. 
**
** Fetch a page by key value.
**
** Whether or not a new page may be allocated by this function depends on
** the value of the createFlag argument.  0 means do not allocate a new

**   5. Otherwise, allocate and return a new page buffer.
*/
static sqlite3_pcache_page *pcache1Fetch(
  sqlite3_pcache *p, 
  unsigned int iKey, 
  int createFlag
){
  unsigned int nPinned;
  PCache1 *pCache = (PCache1 *)p;
  PGroup *pGroup;
  PgHdr1 *pPage = 0;

  assert( offsetof(PgHdr1,page)==0 );
  assert( pCache->bPurgeable || createFlag!=1 );
  assert( pCache->bPurgeable || pCache->nMin==0 );
  assert( pCache->bPurgeable==0 || pCache->nMin==10 );
  assert( pCache->nMin==0 || pCache->bPurgeable );

  pcache1EnterMutex(pGroup = pCache->pGroup);

  /* Step 1: Search the hash table for an existing entry. */
  if( pCache->nHash>0 ){
    unsigned int h = iKey % pCache->nHash;
    for(pPage=pCache->apHash[h]; pPage&&pPage->iKey!=iKey; pPage=pPage->pNext);
  }

  /* Step 2: Abort if no existing page is found and createFlag is 0 */
  if( pPage ){
    if( !pPage->isPinned ) pcache1PinPage(pPage);
    goto fetch_out;
  }
  if( createFlag==0 ){
    goto fetch_out;
  }

  /* The pGroup local variable will normally be initialized by the
  ** pcache1EnterMutex() macro above.  But if SQLITE_MUTEX_OMIT is defined,
  ** then pcache1EnterMutex() is a no-op, so we have to initialize the
  ** local variable here.  Delaying the initialization of pGroup is an
  ** optimization:  The common case is to exit the module before reaching
  ** this point.
  */
#ifdef SQLITE_MUTEX_OMIT
  pGroup = pCache->pGroup;
#endif

  /* Step 3: Abort if createFlag is 1 but the cache is nearly full */
  assert( pCache->nPage >= pCache->nRecyclable );
  nPinned = pCache->nPage - pCache->nRecyclable;
  assert( pGroup->mxPinned == pGroup->nMaxPage + 10 - pGroup->nMinPage );
  assert( pCache->n90pct == pCache->nMax*9/10 );
  if( createFlag==1 && (
        nPinned>=pGroup->mxPinned
     || nPinned>=pCache->n90pct
     || pcache1UnderMemoryPressure(pCache)
  )){
    goto fetch_out;
  }

  if( pCache->nPage>=pCache->nHash && pcache1ResizeHash(pCache) ){
    goto fetch_out;
  }
  assert( pCache->nHash>0 && pCache->apHash );

  /* Step 4. Try to recycle a page. */
  if( pCache->bPurgeable && pGroup->pLruTail && (
         (pCache->nPage+1>=pCache->nMax)
      || pGroup->nCurrentPage>=pGroup->nMaxPage
      || pcache1UnderMemoryPressure(pCache)
  )){
    PCache1 *pOther;
    pPage = pGroup->pLruTail;
    assert( pPage->isPinned==0 );
    pcache1RemoveFromHash(pPage);
    pcache1PinPage(pPage);
    pOther = pPage->pCache;

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

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

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

  if( pPage ){
    unsigned int h = iKey % pCache->nHash;
    pCache->nPage++;
    pPage->iKey = iKey;
    pPage->pNext = pCache->apHash[h];
    pPage->pCache = pCache;
    pPage->pLruPrev = 0;
    pPage->pLruNext = 0;
    pPage->isPinned = 1;
    *(void **)pPage->page.pExtra = 0;
    pCache->apHash[h] = pPage;
  }

fetch_out:
  if( pPage && iKey>pCache->iMaxKey ){
    pCache->iMaxKey = iKey;
  }
  pcache1LeaveMutex(pGroup);
  return (sqlite3_pcache_page*)pPage;
}


/*
** Implementation of the sqlite3_pcache.xUnpin method.
**

   && jrnlSize>pPager->journalOff
  ){
    rc = sqlite3OsTruncate(pPager->jfd, pPager->journalOff);
  }
  return rc;
}

/*
** Find a page in the hash table given its page number. Return
** a pointer to the page or NULL if the requested page is not 
** already in memory.
*/
static PgHdr *pager_lookup(Pager *pPager, Pgno pgno){
  PgHdr *p = 0;                     /* Return value */

  /* It is not possible for a call to PcacheFetch() with createFlag==0 to
  ** fail, since no attempt to allocate dynamic memory will be made.
  */
  (void)sqlite3PcacheFetch(pPager->pPCache, pgno, 0, &p);
  return p;
}

/*
** Discard the entire contents of the in-memory page-cache.
*/
static void pager_reset(Pager *pPager){
  sqlite3BackupRestart(pPager->pBackup);
  sqlite3PcacheClear(pPager->pPCache);
}

      }
    }
  }

#ifdef SQLITE_CHECK_PAGES
  sqlite3PcacheIterateDirty(pPager->pPCache, pager_set_pagehash);
  if( pPager->dbSize==0 && sqlite3PcacheRefCount(pPager->pPCache)>0 ){
    PgHdr *p = pager_lookup(pPager, 1);
    if( p ){
      p->pageHash = 0;
      sqlite3PagerUnrefNotNull(p);
    }
  }
#endif

  ** 2008-04-14:  When attempting to vacuum a corrupt database file, it
  ** is possible to fail a statement on a database that does not yet exist.
  ** Do not attempt to write if database file has never been opened.
  */
  if( pagerUseWal(pPager) ){
    pPg = 0;
  }else{
    pPg = pager_lookup(pPager, pgno);
  }
  assert( pPg || !MEMDB );
  assert( pPager->eState!=PAGER_OPEN || pPg==0 );
  PAGERTRACE(("PLAYBACK %d page %d hash(%08x) %s\n",
           PAGERID(pPager), pgno, pager_datahash(pPager->pageSize, (u8*)aData),
           (isMainJrnl?"main-journal":"sub-journal")
  ));

    if( rc==SQLITE_OK ){
      pager_reset(pPager);
      pPager->dbSize = (Pgno)((nByte+pageSize-1)/pageSize);
      pPager->pageSize = pageSize;
      sqlite3PageFree(pPager->pTmpSpace);
      pPager->pTmpSpace = pNew;
      sqlite3PcacheSetPageSize(pPager->pPCache, pageSize);
    }
  }

  *pPageSize = pPager->pageSize;
  if( rc==SQLITE_OK ){
    if( nReserve<0 ) nReserve = pPager->nReserve;
    assert( nReserve>=0 && nReserve<1000 );

  **
  ** The doNotSpill ROLLBACK and OFF bits inhibits all cache spilling
  ** regardless of whether or not a sync is required.  This is set during
  ** a rollback or by user request, respectively.
  **
  ** Spilling is also prohibited when in an error state since that could
  ** lead to database corruption.   In the current implementaton it 
  ** is impossible for sqlite3PcacheFetch() to be called with createFlag==1
  ** while in the error state, hence it is impossible for this routine to
  ** be called in the error state.  Nevertheless, we include a NEVER()
  ** test for the error state as a safeguard against future changes.
  */
  if( NEVER(pPager->errCode) ) return SQLITE_OK;
  testcase( pPager->doNotSpill & SPILLFLAG_ROLLBACK );
  testcase( pPager->doNotSpill & SPILLFLAG_OFF );

  */
  if( rc==SQLITE_OK ){
    assert( pPager->memDb==0 );
    rc = sqlite3PagerSetPagesize(pPager, &szPageDflt, -1);
    testcase( rc!=SQLITE_OK );
  }








  /* If an error occurred in either of the blocks above, free the 
  ** Pager structure and close the file.
  */
  if( rc!=SQLITE_OK ){
    assert( !pPager->pTmpSpace );
    sqlite3OsClose(pPager->fd);

    sqlite3_free(pPager);
    return rc;
  }

  /* Initialize the PCache object. */
  assert( nExtra<1000 );
  nExtra = ROUND8(nExtra);
  sqlite3PcacheOpen(szPageDflt, nExtra, !memDb,
                    !memDb?pagerStress:0, (void *)pPager, pPager->pPCache);

  PAGERTRACE(("OPEN %d %s\n", FILEHANDLEID(pPager->fd), pPager->zFilename));
  IOTRACE(("OPEN %p %s\n", pPager, pPager->zFilename))

  pPager->useJournal = (u8)useJournal;
  /* pPager->stmtOpen = 0; */
  /* pPager->stmtInUse = 0; */
  /* pPager->nRef = 0; */

  }

  /* If the pager is in the error state, return an error immediately. 
  ** Otherwise, request the page from the PCache layer. */
  if( pPager->errCode!=SQLITE_OK ){
    rc = pPager->errCode;
  }else{

    if( bMmapOk && pagerUseWal(pPager) ){
      rc = sqlite3WalFindFrame(pPager->pWal, pgno, &iFrame);
      if( rc!=SQLITE_OK ) goto pager_acquire_err;
    }

    if( bMmapOk && iFrame==0 ){
      void *pData = 0;

      rc = sqlite3OsFetch(pPager->fd, 
          (i64)(pgno-1) * pPager->pageSize, pPager->pageSize, &pData
      );

      if( rc==SQLITE_OK && pData ){
        if( pPager->eState>PAGER_READER ){
          (void)sqlite3PcacheFetch(pPager->pPCache, pgno, 0, &pPg);
        }
        if( pPg==0 ){
          rc = pagerAcquireMapPage(pPager, pgno, pData, &pPg);
        }else{
          sqlite3OsUnfetch(pPager->fd, (i64)(pgno-1)*pPager->pageSize, pData);
        }
        if( pPg ){
          assert( rc==SQLITE_OK );
          *ppPage = pPg;
          return SQLITE_OK;
        }
      }
      if( rc!=SQLITE_OK ){
        goto pager_acquire_err;
      }
    }



    rc = sqlite3PcacheFetch(pPager->pPCache, pgno, 1, ppPage);







  }

  if( rc!=SQLITE_OK ){
    /* Either the call to sqlite3PcacheFetch() returned an error or the
    ** pager was already in the error-state when this function was called.
    ** Set pPg to 0 and jump to the exception handler.  */
    pPg = 0;

** See also sqlite3PagerGet().  The difference between this routine
** and sqlite3PagerGet() is that _get() will go to the disk and read
** in the page if the page is not already in cache.  This routine
** returns NULL if the page is not in cache or if a disk I/O error 
** has ever happened.
*/
SQLITE_PRIVATE DbPage *sqlite3PagerLookup(Pager *pPager, Pgno pgno){
  PgHdr *pPg = 0;
  assert( pPager!=0 );
  assert( pgno!=0 );
  assert( pPager->pPCache!=0 );
  assert( pPager->eState>=PAGER_READER && pPager->eState!=PAGER_ERROR );
  sqlite3PcacheFetch(pPager->pPCache, pgno, 0, &pPg);
  return pPg;
}

/*
** Release a page reference.
**
** If the number of references to the page drop to zero, then the
** page is added to the LRU list.  When all references to all pages

  /* Update the database size and return.
  */
  if( pPager->dbSize<pPg->pgno ){
    pPager->dbSize = pPg->pgno;
  }
  return rc;
}




























































































/*
** Mark a data page as writeable. This routine must be called before 
** making changes to a page. The caller must check the return value 
** of this function and be careful not to change any page data unless 
** this routine returns SQLITE_OK.
**
** The difference between this function and pager_write() is that this
** function also deals with the special case where 2 or more pages
** fit on a single disk sector. In this case all co-resident pages
** must have been written to the journal file before returning.
**
** If an error occurs, SQLITE_NOMEM or an IO error code is returned
** as appropriate. Otherwise, SQLITE_OK.
*/
SQLITE_PRIVATE int sqlite3PagerWrite(DbPage *pDbPage){
  int rc = SQLITE_OK;

  PgHdr *pPg = pDbPage;
  Pager *pPager = pPg->pPager;

  assert( (pPg->flags & PGHDR_MMAP)==0 );
  assert( pPager->eState>=PAGER_WRITER_LOCKED );
  assert( pPager->eState!=PAGER_ERROR );
  assert( assert_pager_state(pPager) );

  if( pPager->sectorSize > (u32)pPager->pageSize ){
    Pgno nPageCount;          /* Total number of pages in database file */
    Pgno pg1;                 /* First page of the sector pPg is located on. */
    int nPage = 0;            /* Number of pages starting at pg1 to journal */
    int ii;                   /* Loop counter */
    int needSync = 0;         /* True if any page has PGHDR_NEED_SYNC */
    Pgno nPagePerSector = (pPager->sectorSize/pPager->pageSize);

    /* Set the doNotSpill NOSYNC bit to 1. This is because we cannot allow
    ** a journal header to be written between the pages journaled by
    ** this function.
    */
    assert( !MEMDB );
    assert( (pPager->doNotSpill & SPILLFLAG_NOSYNC)==0 );
    pPager->doNotSpill |= SPILLFLAG_NOSYNC;

    /* This trick assumes that both the page-size and sector-size are
    ** an integer power of 2. It sets variable pg1 to the identifier
    ** of the first page of the sector pPg is located on.
    */
    pg1 = ((pPg->pgno-1) & ~(nPagePerSector-1)) + 1;

    nPageCount = pPager->dbSize;
    if( pPg->pgno>nPageCount ){
      nPage = (pPg->pgno - pg1)+1;
    }else if( (pg1+nPagePerSector-1)>nPageCount ){
      nPage = nPageCount+1-pg1;
    }else{
      nPage = nPagePerSector;
    }
    assert(nPage>0);
    assert(pg1<=pPg->pgno);
    assert((pg1+nPage)>pPg->pgno);

    for(ii=0; ii<nPage && rc==SQLITE_OK; ii++){
      Pgno pg = pg1+ii;
      PgHdr *pPage;
      if( pg==pPg->pgno || !sqlite3BitvecTest(pPager->pInJournal, pg) ){
        if( pg!=PAGER_MJ_PGNO(pPager) ){
          rc = sqlite3PagerGet(pPager, pg, &pPage);
          if( rc==SQLITE_OK ){
            rc = pager_write(pPage);
            if( pPage->flags&PGHDR_NEED_SYNC ){
              needSync = 1;
            }
            sqlite3PagerUnrefNotNull(pPage);
          }
        }
      }else if( (pPage = pager_lookup(pPager, pg))!=0 ){
        if( pPage->flags&PGHDR_NEED_SYNC ){
          needSync = 1;
        }
        sqlite3PagerUnrefNotNull(pPage);
      }
    }

    /* If the PGHDR_NEED_SYNC flag is set for any of the nPage pages 
    ** starting at pg1, then it needs to be set for all of them. Because
    ** writing to any of these nPage pages may damage the others, the
    ** journal file must contain sync()ed copies of all of them
    ** before any of them can be written out to the database file.
    */
    if( rc==SQLITE_OK && needSync ){
      assert( !MEMDB );
      for(ii=0; ii<nPage; ii++){
        PgHdr *pPage = pager_lookup(pPager, pg1+ii);
        if( pPage ){
          pPage->flags |= PGHDR_NEED_SYNC;
          sqlite3PagerUnrefNotNull(pPage);
        }
      }
    }

    assert( (pPager->doNotSpill & SPILLFLAG_NOSYNC)!=0 );
    pPager->doNotSpill &= ~SPILLFLAG_NOSYNC;
  }else{
    rc = pager_write(pDbPage);
  }
  return rc;
}

/*
** Return TRUE if the page given in the argument was previously passed
** to sqlite3PagerWrite().  In other words, return TRUE if it is ok
** to change the content of the page.
*/

  /* If the cache contains a page with page-number pgno, remove it
  ** from its hash chain. Also, if the PGHDR_NEED_SYNC flag was set for 
  ** page pgno before the 'move' operation, it needs to be retained 
  ** for the page moved there.
  */
  pPg->flags &= ~PGHDR_NEED_SYNC;
  pPgOld = pager_lookup(pPager, pgno);
  assert( !pPgOld || pPgOld->nRef==1 );
  if( pPgOld ){
    pPg->flags |= (pPgOld->flags&PGHDR_NEED_SYNC);
    if( MEMDB ){
      /* Do not discard pages from an in-memory database since we might
      ** need to rollback later.  Just move the page out of the way. */
      sqlite3PcacheMove(pPgOld, pPager->dbSize+1);

  p->locked = 1;
}

/*
** Release the BtShared mutex associated with B-Tree handle p and
** clear the p->locked boolean.
*/
static void unlockBtreeMutex(Btree *p){
  BtShared *pBt = p->pBt;
  assert( p->locked==1 );
  assert( sqlite3_mutex_held(pBt->mutex) );
  assert( sqlite3_mutex_held(p->db->mutex) );
  assert( p->db==pBt->db );

  sqlite3_mutex_leave(pBt->mutex);
  p->locked = 0;
}




/*
** Enter a mutex on the given BTree object.
**
** If the object is not sharable, then no mutex is ever required
** and this routine is a no-op.  The underlying mutex is non-recursive.
** But we keep a reference count in Btree.wantToLock so the behavior
** of this interface is recursive.
**
** To avoid deadlocks, multiple Btrees are locked in the same order
** by all database connections.  The p->pNext is a list of other
** Btrees belonging to the same database connection as the p Btree
** which need to be locked after p.  If we cannot get a lock on
** p, then first unlock all of the others on p->pNext, then wait
** for the lock to become available on p, then relock all of the
** subsequent Btrees that desire a lock.
*/
SQLITE_PRIVATE void sqlite3BtreeEnter(Btree *p){
  Btree *pLater;

  /* Some basic sanity checking on the Btree.  The list of Btrees
  ** connected by pNext and pPrev should be in sorted order by
  ** Btree.pBt value. All elements of the list should belong to
  ** the same connection. Only shared Btrees are on the list. */
  assert( p->pNext==0 || p->pNext->pBt>p->pBt );
  assert( p->pPrev==0 || p->pPrev->pBt<p->pBt );
  assert( p->pNext==0 || p->pNext->db==p->db );

  /* Unless the database is sharable and unlocked, then BtShared.db
  ** should already be set correctly. */
  assert( (p->locked==0 && p->sharable) || p->pBt->db==p->db );

  if( !p->sharable ) return;
  p->wantToLock++;
  if( p->locked ) return;












  /* In most cases, we should be able to acquire the lock we
  ** want without having to go throught the ascending lock
  ** procedure that follows.  Just be sure not to block.
  */
  if( sqlite3_mutex_try(p->pBt->mutex)==SQLITE_OK ){
    p->pBt->db = p->db;

  lockBtreeMutex(p);
  for(pLater=p->pNext; pLater; pLater=pLater->pNext){
    if( pLater->wantToLock ){
      lockBtreeMutex(pLater);
    }
  }
}


/*
** Exit the recursive mutex on a Btree.
*/
SQLITE_PRIVATE void sqlite3BtreeLeave(Btree *p){
  if( p->sharable ){
    assert( p->wantToLock>0 );

    pCur->eState = CURSOR_REQUIRESEEK;
  }

  invalidateOverflowCache(pCur);
  return rc;
}




/*
** Save the positions of all cursors (except pExcept) that are open on



** the table  with root-page iRoot. Usually, this is called just before cursor
** pExcept is used to modify the table (BtreeDelete() or BtreeInsert()).




*/
static int saveAllCursors(BtShared *pBt, Pgno iRoot, BtCursor *pExcept){
  BtCursor *p;
  assert( sqlite3_mutex_held(pBt->mutex) );
  assert( pExcept==0 || pExcept->pBt==pBt );
  for(p=pBt->pCursor; p; p=p->pNext){
















    if( p!=pExcept && (0==iRoot || p->pgnoRoot==iRoot) ){
      if( p->eState==CURSOR_VALID ){
        int rc = saveCursorPosition(p);
        if( SQLITE_OK!=rc ){
          return rc;
        }
      }else{
        testcase( p->iPage>0 );
        btreeReleaseAllCursorPages(p);
      }
    }

  }
  return SQLITE_OK;
}

/*
** Clear the current cursor position.
*/
SQLITE_PRIVATE void sqlite3BtreeClearCursor(BtCursor *pCur){

#define restoreCursorPosition(p) \
  (p->eState>=CURSOR_REQUIRESEEK ? \
         btreeRestoreCursorPosition(p) : \
         SQLITE_OK)

/*
** Determine whether or not a cursor has moved from the position it

** was last placed at.  Cursors can move when the row they are pointing
** at is deleted out from under them.

**
** This routine returns an error code if something goes wrong.  The
** integer *pHasMoved is set as follows:
**
**    0:   The cursor is unchanged
**    1:   The cursor is still pointing at the same row, but the pointers


**         returned by sqlite3BtreeKeyFetch() or sqlite3BtreeDataFetch()


**         might now be invalid because of a balance() or other change to the
**         b-tree.

**    2:   The cursor is no longer pointing to the row.  The row might have

**         been deleted out from under the cursor.








*/
SQLITE_PRIVATE int sqlite3BtreeCursorHasMoved(BtCursor *pCur, int *pHasMoved){
  int rc;


  if( pCur->eState==CURSOR_VALID ){
    *pHasMoved = 0;
    return SQLITE_OK;
  }
  rc = restoreCursorPosition(pCur);
  if( rc ){
    *pHasMoved = 2;
    return rc;
  }
  if( pCur->eState!=CURSOR_VALID || NEVER(pCur->skipNext!=0) ){
    *pHasMoved = 2;
  }else{
    *pHasMoved = 1;
  }
  return SQLITE_OK;
}

#ifndef SQLITE_OMIT_AUTOVACUUM
/*
** Given a page number of a regular database page, return the page

** the first two bytes past the cell pointer area since presumably this
** allocation is being made in order to insert a new cell, so we will
** also end up needing a new cell pointer.
*/
static int allocateSpace(MemPage *pPage, int nByte, int *pIdx){
  const int hdr = pPage->hdrOffset;    /* Local cache of pPage->hdrOffset */
  u8 * const data = pPage->aData;      /* Local cache of pPage->aData */
  int nFrag;                           /* Number of fragmented bytes on pPage */
  int top;                             /* First byte of cell content area */
  int gap;        /* First byte of gap between cell pointers and cell content */
  int rc;         /* Integer return code */
  int usableSize; /* Usable size of the page */
  
  assert( sqlite3PagerIswriteable(pPage->pDbPage) );
  assert( pPage->pBt );
  assert( sqlite3_mutex_held(pPage->pBt->mutex) );
  assert( nByte>=0 );  /* Minimum cell size is 4 */
  assert( pPage->nFree>=nByte );
  assert( pPage->nOverflow==0 );
  usableSize = pPage->pBt->usableSize;
  assert( nByte < usableSize-8 );

  nFrag = data[hdr+7];
  assert( pPage->cellOffset == hdr + 12 - 4*pPage->leaf );
  gap = pPage->cellOffset + 2*pPage->nCell;

  top = get2byteNotZero(&data[hdr+5]);
  if( gap>top ) return SQLITE_CORRUPT_BKPT;
  testcase( gap+2==top );
  testcase( gap+1==top );
  testcase( gap==top );



  if( nFrag>=60 ){
    /* Always defragment highly fragmented pages */
    rc = defragmentPage(pPage);
    if( rc ) return rc;
    top = get2byteNotZero(&data[hdr+5]);
  }else if( gap+2<=top ){
    /* Search the freelist looking for a free slot big enough to satisfy 
    ** the request. The allocation is made from the first free slot in 
    ** the list that is large enough to accommodate it.
    */




    int pc, addr;
    for(addr=hdr+1; (pc = get2byte(&data[addr]))>0; addr=pc){
      int size;            /* Size of the free slot */
      if( pc>usableSize-4 || pc<addr+4 ){
        return SQLITE_CORRUPT_BKPT;
      }
      size = get2byte(&data[pc+2]);
      if( size>=nByte ){
        int x = size - nByte;
        testcase( x==4 );
        testcase( x==3 );
        if( x<4 ){

          /* Remove the slot from the free-list. Update the number of
          ** fragmented bytes within the page. */
          memcpy(&data[addr], &data[pc], 2);
          data[hdr+7] = (u8)(nFrag + x);
        }else if( size+pc > usableSize ){
          return SQLITE_CORRUPT_BKPT;
        }else{
          /* The slot remains on the free-list. Reduce its size to account
          ** for the portion used by the new allocation. */
          put2byte(&data[pc+2], x);
        }
        *pIdx = pc + x;
        return SQLITE_OK;
      }
    }
  }

  /* Check to make sure there is enough space in the gap to satisfy
  ** the allocation.  If not, defragment.
  */
  testcase( gap+2+nByte==top );
  if( gap+2+nByte>top ){


    rc = defragmentPage(pPage);
    if( rc ) return rc;
    top = get2byteNotZero(&data[hdr+5]);
    assert( gap+nByte<=top );
  }

  assert( top+nByte <= (int)pPage->pBt->usableSize );
  *pIdx = top;
  return SQLITE_OK;
}

/*
** Return a section of the pPage->aData to the freelist.
** The first byte of the new free block is pPage->aDisk[start]
** and the size of the block is "size" bytes.
**
** Most of the effort here is involved in coalesing adjacent



** free blocks into a single big free block.


*/
static int freeSpace(MemPage *pPage, int start, int size){


  int addr, pbegin, hdr;


  int iLast;                        /* Largest possible freeblock offset */

  unsigned char *data = pPage->aData;

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


  if( pPage->pBt->btsFlags & BTS_SECURE_DELETE ){
    /* 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
  ** the freelist.  So we do need to check for corruption while scanning
  ** the freelist.
  */
  hdr = pPage->hdrOffset;
  addr = hdr + 1;
  iLast = pPage->pBt->usableSize - 4;

  assert( start<=iLast );
  while( (pbegin = get2byte(&data[addr]))<start && pbegin>0 ){
    if( pbegin<addr+4 ){
      return SQLITE_CORRUPT_BKPT;
    }
    addr = pbegin;
  }
  if( pbegin>iLast ){
    return SQLITE_CORRUPT_BKPT;

  }

  assert( pbegin>addr || pbegin==0 );







  put2byte(&data[addr], start);
  put2byte(&data[start], pbegin);
  put2byte(&data[start+2], size);

  pPage->nFree = pPage->nFree + (u16)size;



  /* Coalesce adjacent free blocks */
  addr = hdr + 1;
  while( (pbegin = get2byte(&data[addr]))>0 ){
    int pnext, psize, x;
    assert( pbegin>addr );
    assert( pbegin <= (int)pPage->pBt->usableSize-4 );
    pnext = get2byte(&data[pbegin]);
    psize = get2byte(&data[pbegin+2]);
    if( pbegin + psize + 3 >= pnext && pnext>0 ){
      int frag = pnext - (pbegin+psize);
      if( (frag<0) || (frag>(int)data[hdr+7]) ){
        return SQLITE_CORRUPT_BKPT;



      }


      data[hdr+7] -= (u8)frag;

      x = get2byte(&data[pnext]);




      put2byte(&data[pbegin], x);
      x = pnext + get2byte(&data[pnext+2]) - pbegin;
      put2byte(&data[pbegin+2], x);
    }else{
      addr = pbegin;
    }
  }

  /* If the cell content area begins with a freeblock, remove it. */
  if( data[hdr+1]==data[hdr+5] && data[hdr+2]==data[hdr+6] ){
    int top;
    pbegin = get2byte(&data[hdr+1]);
    memcpy(&data[hdr+1], &data[pbegin], 2);
    top = get2byte(&data[hdr+5]) + get2byte(&data[pbegin+2]);
    put2byte(&data[hdr+5], top);
  }
  assert( sqlite3PagerIswriteable(pPage->pDbPage) );
  return SQLITE_OK;
}

/*
** Decode the flags byte (the first byte of the header) for a page
** and initialize fields of the MemPage structure accordingly.
**

static int moveToRightmost(BtCursor *pCur){
  Pgno pgno;
  int rc = SQLITE_OK;
  MemPage *pPage = 0;

  assert( cursorHoldsMutex(pCur) );
  assert( pCur->eState==CURSOR_VALID );
  while( rc==SQLITE_OK && !(pPage = pCur->apPage[pCur->iPage])->leaf ){
    pgno = get4byte(&pPage->aData[pPage->hdrOffset+8]);
    pCur->aiIdx[pCur->iPage] = pPage->nCell;
    rc = moveToChild(pCur, pgno);

  }
  if( rc==SQLITE_OK ){
    pCur->aiIdx[pCur->iPage] = pPage->nCell-1;
    pCur->info.nSize = 0;
    pCur->curFlags &= ~BTCF_ValidNKey;
  }
  return rc;
}

/* Move the cursor to the first entry in the table.  Return SQLITE_OK
** on success.  Set *pRes to 0 if the cursor actually points to something
** or set *pRes to 1 if the table is empty.
*/
SQLITE_PRIVATE int sqlite3BtreeFirst(BtCursor *pCur, int *pRes){

      *pRes = -1;
      return SQLITE_OK;
    }
  }

  if( pIdxKey ){
    xRecordCompare = sqlite3VdbeFindCompare(pIdxKey);
    pIdxKey->isCorrupt = 0;
    assert( pIdxKey->default_rc==1 
         || pIdxKey->default_rc==0 
         || pIdxKey->default_rc==-1
    );
  }else{
    xRecordCompare = 0; /* All keys are integers */
  }

          if( rc ){
            sqlite3_free(pCellKey);
            goto moveto_finish;
          }
          c = xRecordCompare(nCell, pCellKey, pIdxKey, 0);
          sqlite3_free(pCellKey);
        }
        assert( pIdxKey->isCorrupt==0 || c==0 );



        if( c<0 ){
          lwr = idx+1;
        }else if( c>0 ){
          upr = idx-1;
        }else{
          assert( c==0 );
          *pRes = 0;
          rc = SQLITE_OK;
          pCur->aiIdx[pCur->iPage] = (u16)idx;
          if( pIdxKey->isCorrupt ) rc = SQLITE_CORRUPT;
          goto moveto_finish;
        }
        if( lwr>upr ) break;
        assert( lwr+upr>=0 );
        idx = (lwr+upr)>>1;  /* idx = (lwr+upr)/2 */
      }
    }

}

/*
** Advance the cursor to the next entry in the database.  If
** successful then set *pRes=0.  If the cursor
** was already pointing to the last entry in the database before
** this routine was called, then set *pRes=1.






**
** The calling function will set *pRes to 0 or 1.  The initial *pRes value
** will be 1 if the cursor being stepped corresponds to an SQL index and
** if this routine could have been skipped if that SQL index had been
** a unique index.  Otherwise the caller will have set *pRes to zero.
** Zero is the common case. The btree implementation is free to use the
** initial *pRes value as a hint to improve performance, but the current
** SQLite btree implementation does not. (Note that the comdb2 btree
** implementation does use this hint, however.)
*/
SQLITE_PRIVATE int sqlite3BtreeNext(BtCursor *pCur, int *pRes){
  int rc;
  int idx;
  MemPage *pPage;

  assert( cursorHoldsMutex(pCur) );
  assert( pRes!=0 );
  assert( *pRes==0 || *pRes==1 );
  assert( pCur->skipNext==0 || pCur->eState!=CURSOR_VALID );
  if( pCur->eState!=CURSOR_VALID ){
    invalidateOverflowCache(pCur);
    rc = restoreCursorPosition(pCur);
    if( rc!=SQLITE_OK ){
      *pRes = 0;
      return rc;
    }
    if( CURSOR_INVALID==pCur->eState ){
      *pRes = 1;
      return SQLITE_OK;
    }
    if( pCur->skipNext ){
      assert( pCur->eState==CURSOR_VALID || pCur->eState==CURSOR_SKIPNEXT );
      pCur->eState = CURSOR_VALID;
      if( pCur->skipNext>0 ){
        pCur->skipNext = 0;
        *pRes = 0;
        return SQLITE_OK;
      }
      pCur->skipNext = 0;
    }
  }

  pPage = pCur->apPage[pCur->iPage];
  idx = ++pCur->aiIdx[pCur->iPage];
  assert( pPage->isInit );

  /* If the database file is corrupt, it is possible for the value of idx 
  ** to be invalid here. This can only occur if a second cursor modifies
  ** the page while cursor pCur is holding a reference to it. Which can
  ** only happen if the database is corrupt in such a way as to link the
  ** page into more than one b-tree structure. */
  testcase( idx>pPage->nCell );

  pCur->info.nSize = 0;
  pCur->curFlags &= ~(BTCF_ValidNKey|BTCF_ValidOvfl);
  if( idx>=pPage->nCell ){
    if( !pPage->leaf ){
      rc = moveToChild(pCur, get4byte(&pPage->aData[pPage->hdrOffset+8]));
      if( rc ){
        *pRes = 0;
        return rc;
      }
      rc = moveToLeftmost(pCur);
      *pRes = 0;
      return rc;
    }
    do{
      if( pCur->iPage==0 ){
        *pRes = 1;
        pCur->eState = CURSOR_INVALID;
        return SQLITE_OK;
      }
      moveToParent(pCur);
      pPage = pCur->apPage[pCur->iPage];
    }while( pCur->aiIdx[pCur->iPage]>=pPage->nCell );
    *pRes = 0;
    if( pPage->intKey ){
      rc = sqlite3BtreeNext(pCur, pRes);
    }else{
      rc = SQLITE_OK;
    }


    return rc;


  }









  *pRes = 0;






  if( pPage->leaf ){
    return SQLITE_OK;
  }
  rc = moveToLeftmost(pCur);
  return rc;
}


/*
** Step the cursor to the back to the previous entry in the database.  If
** successful then set *pRes=0.  If the cursor
** was already pointing to the first entry in the database before
** this routine was called, then set *pRes=1.






**
** The calling function will set *pRes to 0 or 1.  The initial *pRes value
** will be 1 if the cursor being stepped corresponds to an SQL index and
** if this routine could have been skipped if that SQL index had been
** a unique index.  Otherwise the caller will have set *pRes to zero.
** Zero is the common case. The btree implementation is free to use the
** initial *pRes value as a hint to improve performance, but the current
** SQLite btree implementation does not. (Note that the comdb2 btree
** implementation does use this hint, however.)
*/
SQLITE_PRIVATE int sqlite3BtreePrevious(BtCursor *pCur, int *pRes){
  int rc;
  MemPage *pPage;

  assert( cursorHoldsMutex(pCur) );
  assert( pRes!=0 );
  assert( *pRes==0 || *pRes==1 );
  assert( pCur->skipNext==0 || pCur->eState!=CURSOR_VALID );
  pCur->curFlags &= ~(BTCF_AtLast|BTCF_ValidOvfl);

  if( pCur->eState!=CURSOR_VALID ){
    if( ALWAYS(pCur->eState>=CURSOR_REQUIRESEEK) ){
      rc = btreeRestoreCursorPosition(pCur);
      if( rc!=SQLITE_OK ){
        *pRes = 0;
        return rc;
      }
    }
    if( CURSOR_INVALID==pCur->eState ){
      *pRes = 1;
      return SQLITE_OK;
    }
    if( pCur->skipNext ){
      assert( pCur->eState==CURSOR_VALID || pCur->eState==CURSOR_SKIPNEXT );
      pCur->eState = CURSOR_VALID;
      if( pCur->skipNext<0 ){
        pCur->skipNext = 0;
        *pRes = 0;
        return SQLITE_OK;
      }
      pCur->skipNext = 0;
    }
  }

  pPage = pCur->apPage[pCur->iPage];
  assert( pPage->isInit );
  if( !pPage->leaf ){
    int idx = pCur->aiIdx[pCur->iPage];
    rc = moveToChild(pCur, get4byte(findCell(pPage, idx)));
    if( rc ){
      *pRes = 0;
      return rc;
    }
    rc = moveToRightmost(pCur);
  }else{
    while( pCur->aiIdx[pCur->iPage]==0 ){
      if( pCur->iPage==0 ){
        pCur->eState = CURSOR_INVALID;
        *pRes = 1;
        return SQLITE_OK;
      }
      moveToParent(pCur);
    }
    pCur->info.nSize = 0;
    pCur->curFlags &= ~(BTCF_ValidNKey|BTCF_ValidOvfl);

    pCur->aiIdx[pCur->iPage]--;
    pPage = pCur->apPage[pCur->iPage];
    if( pPage->intKey && !pPage->leaf ){
      rc = sqlite3BtreePrevious(pCur, pRes);
    }else{
      rc = SQLITE_OK;
    }
  }







  *pRes = 0;









  return rc;
}

/*
** Allocate a new page from the database file.
**
** The new page is marked as dirty.  (In other words, sqlite3PagerWrite()
** has already been called on the new page.)  The new page has also

  int i = sqlite3FindDbName(pDb, zDb);

  if( i==1 ){
    Parse *pParse;
    int rc = 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);
      sqlite3ParserReset(pParse);
      sqlite3StackFree(pErrorDb, pParse);
    }
    if( rc ){
      return 0;
    }
  }

  if( i<0 ){
    sqlite3Error(pErrorDb, SQLITE_ERROR, "unknown database %s", zDb);
    return 0;
  }

  return pDb->aDb[i].pBt;
}

/*

  ** database connection while a backup is in progress may cause
  ** a malfunction or a deadlock.
  */
  sqlite3_mutex_enter(pSrcDb->mutex);
  sqlite3_mutex_enter(pDestDb->mutex);

  if( pSrcDb==pDestDb ){
    sqlite3Error(
        pDestDb, SQLITE_ERROR, "source and destination must be distinct"
    );
    p = 0;
  }else {
    /* Allocate space for a new sqlite3_backup object...
    ** EVIDENCE-OF: R-64852-21591 The sqlite3_backup object is created by a
    ** call to sqlite3_backup_init() and is destroyed by a call to
    ** sqlite3_backup_finish(). */
    p = (sqlite3_backup *)sqlite3MallocZero(sizeof(sqlite3_backup));
    if( !p ){
      sqlite3Error(pDestDb, SQLITE_NOMEM, 0);
    }
  }

  /* If the allocation succeeded, populate the new object. */
  if( p ){
    p->pSrc = findBtree(pDestDb, pSrcDb, zSrcDb);
    p->pDest = findBtree(pDestDb, pDestDb, zDestDb);

  /* If a transaction is still open on the Btree, roll it back. */
  sqlite3BtreeRollback(p->pDest, SQLITE_OK);

  /* Set the error code of the destination database handle. */
  rc = (p->rc==SQLITE_DONE) ? SQLITE_OK : p->rc;
  if( p->pDestDb ){
    sqlite3Error(p->pDestDb, rc, 0);

    /* Exit the mutexes and free the backup context structure. */
    sqlite3LeaveMutexAndCloseZombie(p->pDestDb);
  }
  sqlite3BtreeLeave(p->pSrc);
  if( p->pDestDb ){
    /* EVIDENCE-OF: R-64852-21591 The sqlite3_backup object is created by a

      pMem->z = pMem->zMalloc = sqlite3DbReallocOrFree(pMem->db, pMem->z, n);
      bPreserve = 0;
    }else{
      sqlite3DbFree(pMem->db, pMem->zMalloc);
      pMem->zMalloc = sqlite3DbMallocRaw(pMem->db, n);
    }
    if( pMem->zMalloc==0 ){
      VdbeMemRelease(pMem);
      pMem->z = 0;
      pMem->flags = MEM_Null;  
      return SQLITE_NOMEM;
    }
  }

  if( pMem->z && bPreserve && pMem->z!=pMem->zMalloc ){

    pMem->n += pMem->u.nZero;
    pMem->flags &= ~(MEM_Zero|MEM_Term);
  }
  return SQLITE_OK;
}
#endif


/*

** Make sure the given Mem is \u0000 terminated.
*/
SQLITE_PRIVATE int sqlite3VdbeMemNulTerminate(Mem *pMem){
  assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
  if( (pMem->flags & MEM_Term)!=0 || (pMem->flags & MEM_Str)==0 ){
    return SQLITE_OK;   /* Nothing to do */
  }
  if( sqlite3VdbeMemGrow(pMem, pMem->n+2, 1) ){
    return SQLITE_NOMEM;
  }
  pMem->z[pMem->n] = 0;
  pMem->z[pMem->n+1] = 0;
  pMem->flags |= MEM_Term;
  return SQLITE_OK;
}















/*
** Add MEM_Str to the set of representations for the given Mem.  Numbers
** are converted using sqlite3_snprintf().  Converting a BLOB to a string
** is a no-op.
**
** Existing representations MEM_Int and MEM_Real are *not* invalidated.

**
** A MEM_Null value will never be passed to this function. This function is
** used for converting values to text for returning to the user (i.e. via
** sqlite3_value_text()), or for ensuring that values to be used as btree
** keys are strings. In the former case a NULL pointer is returned the
** user and the later is an internal programming error.
*/
SQLITE_PRIVATE int sqlite3VdbeMemStringify(Mem *pMem, int enc){
  int rc = SQLITE_OK;
  int fg = pMem->flags;
  const int nByte = 32;

  assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
  assert( !(fg&MEM_Zero) );
  assert( !(fg&(MEM_Str|MEM_Blob)) );
  assert( fg&(MEM_Int|MEM_Real) );
  assert( (pMem->flags&MEM_RowSet)==0 );
  assert( EIGHT_BYTE_ALIGNMENT(pMem) );


  if( sqlite3VdbeMemGrow(pMem, nByte, 0) ){
    return SQLITE_NOMEM;
  }

  /* For a Real or Integer, use sqlite3_mprintf() to produce the UTF-8
  ** string representation of the value. Then, if the required encoding
  ** is UTF-16le or UTF-16be do a translation.
  ** 
  ** FIX ME: It would be better if sqlite3_snprintf() could do UTF-16.
  */
  if( fg & MEM_Int ){
    sqlite3_snprintf(nByte, pMem->z, "%lld", pMem->u.i);
  }else{
    assert( fg & MEM_Real );
    sqlite3_snprintf(nByte, pMem->z, "%!.15g", pMem->r);
  }
  pMem->n = sqlite3Strlen30(pMem->z);
  pMem->enc = SQLITE_UTF8;
  pMem->flags |= MEM_Str|MEM_Term;

  sqlite3VdbeChangeEncoding(pMem, enc);
  return rc;
}

/*
** Memory cell pMem contains the context of an aggregate function.
** This routine calls the finalize method for that function.  The
** result of the aggregate is stored back into pMem.
**
** Return SQLITE_ERROR if the finalizer reports an error.  SQLITE_OK
** otherwise.
*/
SQLITE_PRIVATE int sqlite3VdbeMemFinalize(Mem *pMem, FuncDef *pFunc){
  int rc = SQLITE_OK;
  if( ALWAYS(pFunc && pFunc->xFinalize) ){
    sqlite3_context ctx;

    assert( (pMem->flags & MEM_Null)!=0 || pFunc==pMem->u.pDef );
    assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
    memset(&ctx, 0, sizeof(ctx));

    ctx.s.flags = MEM_Null;
    ctx.s.db = pMem->db;

    ctx.pMem = pMem;
    ctx.pFunc = pFunc;
    pFunc->xFinalize(&ctx); /* IMP: R-24505-23230 */
    assert( 0==(pMem->flags&MEM_Dyn) && !pMem->xDel );
    sqlite3DbFree(pMem->db, pMem->zMalloc);
    memcpy(pMem, &ctx.s, sizeof(ctx.s));
    rc = ctx.isError;
  }
  return rc;
}

/*
** If the memory cell contains a string value that must be freed by
** invoking an external callback, free it now. Calling this function
** does not free any Mem.zMalloc buffer.



*/
SQLITE_PRIVATE void sqlite3VdbeMemReleaseExternal(Mem *p){
  assert( p->db==0 || sqlite3_mutex_held(p->db->mutex) );
  if( p->flags&MEM_Agg ){
    sqlite3VdbeMemFinalize(p, p->u.pDef);
    assert( (p->flags & MEM_Agg)==0 );
    sqlite3VdbeMemRelease(p);
  }else if( p->flags&MEM_Dyn ){
    assert( (p->flags&MEM_RowSet)==0 );
    assert( p->xDel!=SQLITE_DYNAMIC && p->xDel!=0 );
    p->xDel((void *)p->z);
    p->xDel = 0;
  }else if( p->flags&MEM_RowSet ){
    sqlite3RowSetClear(p->u.pRowSet);
  }else if( p->flags&MEM_Frame ){
    sqlite3VdbeMemSetNull(p);
  }
}




















/*
** Release any memory held by the Mem. This may leave the Mem in an
** inconsistent state, for example with (Mem.z==0) and
** (Mem.flags==MEM_Str).
*/
SQLITE_PRIVATE void sqlite3VdbeMemRelease(Mem *p){
  assert( sqlite3VdbeCheckMemInvariants(p) );

  VdbeMemRelease(p);
  if( p->zMalloc ){
    sqlite3DbFree(p->db, p->zMalloc);
    p->zMalloc = 0;
  }
  p->z = 0;
  assert( p->xDel==0 );  /* Zeroed by VdbeMemRelease() above */
}

/*
** Convert a 64-bit IEEE double into a 64-bit signed integer.
** If the double is out of range of a 64-bit signed integer then
** return the closest available 64-bit signed integer.
*/

  if( flags & MEM_Int ){
    return pMem->u.i;
  }else if( flags & MEM_Real ){
    return doubleToInt64(pMem->r);
  }else if( flags & (MEM_Str|MEM_Blob) ){
    i64 value = 0;
    assert( pMem->z || pMem->n==0 );
    testcase( pMem->z==0 );
    sqlite3Atoi64(pMem->z, &value, pMem->n, pMem->enc);
    return value;
  }else{
    return 0;
  }
}

      sqlite3VdbeIntegerAffinity(pMem);
    }
  }
  assert( (pMem->flags & (MEM_Int|MEM_Real|MEM_Null))!=0 );
  pMem->flags &= ~(MEM_Str|MEM_Blob);
  return SQLITE_OK;
}














































/*
** Delete any previous value and set the value stored in *pMem to NULL.
*/
SQLITE_PRIVATE void sqlite3VdbeMemSetNull(Mem *pMem){
  if( pMem->flags & MEM_Frame ){
    VdbeFrame *pFrame = pMem->u.pFrame;

  sqlite3VdbeMemGrow(pMem, n, 0);
  if( pMem->z ){
    pMem->n = n;
    memset(pMem->z, 0, n);
  }
#endif
}












/*
** Delete any previous value and set the value stored in *pMem to val,
** manifest type INTEGER.
*/
SQLITE_PRIVATE void sqlite3VdbeMemSetInt64(Mem *pMem, i64 val){
  sqlite3VdbeMemRelease(pMem);


  pMem->u.i = val;
  pMem->flags = MEM_Int;

}

#ifndef SQLITE_OMIT_FLOATING_POINT
/*
** Delete any previous value and set the value stored in *pMem to val,
** manifest type REAL.
*/

** Make an shallow copy of pFrom into pTo.  Prior contents of
** pTo are freed.  The pFrom->z field is not duplicated.  If
** pFrom->z is used, then pTo->z points to the same thing as pFrom->z
** and flags gets srcType (either MEM_Ephem or MEM_Static).
*/
SQLITE_PRIVATE void sqlite3VdbeMemShallowCopy(Mem *pTo, const Mem *pFrom, int srcType){
  assert( (pFrom->flags & MEM_RowSet)==0 );
  VdbeMemRelease(pTo);
  memcpy(pTo, pFrom, MEMCELLSIZE);
  pTo->xDel = 0;
  if( (pFrom->flags&MEM_Static)==0 ){
    pTo->flags &= ~(MEM_Dyn|MEM_Static|MEM_Ephem);
    assert( srcType==MEM_Ephem || srcType==MEM_Static );
    pTo->flags |= srcType;
  }
}

/*
** Make a full copy of pFrom into pTo.  Prior contents of pTo are
** freed before the copy is made.
*/
SQLITE_PRIVATE int sqlite3VdbeMemCopy(Mem *pTo, const Mem *pFrom){
  int rc = SQLITE_OK;

  assert( (pFrom->flags & MEM_RowSet)==0 );
  VdbeMemRelease(pTo);
  memcpy(pTo, pFrom, MEMCELLSIZE);
  pTo->flags &= ~MEM_Dyn;
  pTo->xDel = 0;

  if( pTo->flags&(MEM_Str|MEM_Blob) ){
    if( 0==(pFrom->flags&MEM_Static) ){
      pTo->flags |= MEM_Ephem;

    }else{
      sqlite3VdbeMemRelease(pMem);
    }
  }

  return rc;
}








































/* This function is only available internally, it is not part of the
** external API. It works in a similar way to sqlite3_value_text(),
** except the data returned is in the encoding specified by the second
** parameter, which must be one of SQLITE_UTF16BE, SQLITE_UTF16LE or
** SQLITE_UTF8.
**
** (2006-02-16:)  The enc value can be or-ed with SQLITE_UTF16_ALIGNED.
** If that is the case, then the result must be aligned on an even byte
** boundary.
*/
SQLITE_PRIVATE const void *sqlite3ValueText(sqlite3_value* pVal, u8 enc){
  if( !pVal ) return 0;

  assert( pVal->db==0 || sqlite3_mutex_held(pVal->db->mutex) );
  assert( (enc&3)==(enc&~SQLITE_UTF16_ALIGNED) );
  assert( (pVal->flags & MEM_RowSet)==0 );

  if( pVal->flags&MEM_Null ){
    return 0;
  }
  assert( (MEM_Blob>>3) == MEM_Str );
  pVal->flags |= (pVal->flags & MEM_Blob)>>3;
  ExpandBlob(pVal);
  if( pVal->flags&MEM_Str ){
    sqlite3VdbeChangeEncoding(pVal, enc & ~SQLITE_UTF16_ALIGNED);
    if( (enc & SQLITE_UTF16_ALIGNED)!=0 && 1==(1&SQLITE_PTR_TO_INT(pVal->z)) ){
      assert( (pVal->flags & (MEM_Ephem|MEM_Static))!=0 );
      if( sqlite3VdbeMemMakeWriteable(pVal)!=SQLITE_OK ){
        return 0;
      }
    }
    sqlite3VdbeMemNulTerminate(pVal); /* IMP: R-31275-44060 */
  }else{
    assert( (pVal->flags&MEM_Blob)==0 );
    sqlite3VdbeMemStringify(pVal, enc);
    assert( 0==(1&SQLITE_PTR_TO_INT(pVal->z)) );
  }
  assert(pVal->enc==(enc & ~SQLITE_UTF16_ALIGNED) || pVal->db==0
              || pVal->db->mallocFailed );
  if( pVal->enc==(enc & ~SQLITE_UTF16_ALIGNED) ){
    return pVal->z;
  }else{
    return 0;
  }
}

/*
** Create a new sqlite3_value object.
*/
SQLITE_PRIVATE sqlite3_value *sqlite3ValueNew(sqlite3 *db){
  Mem *p = sqlite3DbMallocZero(db, sizeof(*p));

  const char *zNeg = "";
  int rc = SQLITE_OK;

  if( !pExpr ){
    *ppVal = 0;
    return SQLITE_OK;
  }
  op = pExpr->op;
  if( NEVER(op==TK_REGISTER) ) op = pExpr->op2;












  /* Handle negative integers in a single step.  This is needed in the
  ** case when the value is -9223372036854775808.
  */
  if( op==TK_UMINUS
   && (pExpr->pLeft->op==TK_INTEGER || pExpr->pLeft->op==TK_FLOAT) ){
    pExpr = pExpr->pLeft;

  nRet = 1 + nSerial + nVal;
  aRet = sqlite3DbMallocRaw(db, nRet);
  if( aRet==0 ){
    sqlite3_result_error_nomem(context);
  }else{
    aRet[0] = nSerial+1;
    sqlite3PutVarint(&aRet[1], iSerial);
    sqlite3VdbeSerialPut(&aRet[1+nSerial], argv[0], iSerial);
    sqlite3_result_blob(context, aRet, nRet, SQLITE_TRANSIENT);
    sqlite3DbFree(db, aRet);
  }
}

/*

    sqlite3BeginBenignMalloc();
    if( db->pErr==0 ) db->pErr = sqlite3ValueNew(db);
    sqlite3ValueSetStr(db->pErr, -1, p->zErrMsg, SQLITE_UTF8, SQLITE_TRANSIENT);
    sqlite3EndBenignMalloc();
    db->mallocFailed = mallocFailed;
    db->errCode = rc;
  }else{
    sqlite3Error(db, rc, 0);
  }
  return rc;
}

#ifdef SQLITE_ENABLE_SQLLOG
/*
** If an SQLITE_CONFIG_SQLLOG hook is registered and the VM has been run, 

    p->zErrMsg = 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, p->zErrMsg ? "%s" : 0, p->zErrMsg);
    sqlite3DbFree(db, p->zErrMsg);
    p->zErrMsg = 0;
  }

  /* Reclaim all memory used by the VDBE
  */
  Cleanup(p);

  if( p->pNext ){
    p->pNext->pPrev = p->pPrev;
  }
  p->magic = VDBE_MAGIC_DEAD;
  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.
**
** If a MoveTo operation is pending on the given cursor, then do that
** MoveTo now.  If no move is pending, check to see if the row has been
** deleted out from under the cursor and if it has, mark the row as
** a NULL row.
**
** If the cursor is already pointing to the correct row and that row has
** not been deleted out from under the cursor, then this routine is a no-op.
*/
SQLITE_PRIVATE int sqlite3VdbeCursorMoveto(VdbeCursor *p){
  if( p->deferredMoveto ){
    int res, rc;
#ifdef SQLITE_TEST
    extern int sqlite3_search_count;
#endif
    assert( p->isTable );
    rc = sqlite3BtreeMovetoUnpacked(p->pCursor, 0, p->movetoTarget, 0, &res);
    if( rc ) return rc;
    p->lastRowid = p->movetoTarget;
    if( res!=0 ) return SQLITE_CORRUPT_BKPT;
    p->rowidIsValid = 1;
#ifdef SQLITE_TEST
    sqlite3_search_count++;
#endif
    p->deferredMoveto = 0;
    p->cacheStatus = CACHE_STALE;
  }else if( p->pCursor ){
    int hasMoved;
    int rc = sqlite3BtreeCursorHasMoved(p->pCursor, &hasMoved);
    if( rc ) return rc;
    if( hasMoved ){
      p->cacheStatus = CACHE_STALE;
      if( hasMoved==2 ) p->nullRow = 1;
    }


  }
  return SQLITE_OK;
}

/*
** The following functions:
**

      assert( sizeof(v)==sizeof(pMem->r) );
      memcpy(&v, &pMem->r, sizeof(v));
      swapMixedEndianFloat(v);
    }else{
      v = pMem->u.i;
    }
    len = i = sqlite3VdbeSerialTypeLen(serial_type);
    while( i-- ){

      buf[i] = (u8)(v&0xFF);
      v >>= 8;
    }
    return len;
  }

  /* String or blob */
  if( serial_type>=12 ){
    assert( pMem->n + ((pMem->flags & MEM_Zero)?pMem->u.nZero:0)
             == (int)sqlite3VdbeSerialTypeLen(serial_type) );

/* Input "x" is a sequence of unsigned characters that represent a
** big-endian integer.  Return the equivalent native integer
*/
#define ONE_BYTE_INT(x)    ((i8)(x)[0])
#define TWO_BYTE_INT(x)    (256*(i8)((x)[0])|(x)[1])
#define THREE_BYTE_INT(x)  (65536*(i8)((x)[0])|((x)[1]<<8)|(x)[2])
#define FOUR_BYTE_UINT(x)  (((u32)(x)[0]<<24)|((x)[1]<<16)|((x)[2]<<8)|(x)[3])


/*
** Deserialize the data blob pointed to by buf as serial type serial_type
** and store the result in pMem.  Return the number of bytes read.





*/ 
































SQLITE_PRIVATE u32 sqlite3VdbeSerialGet(
  const unsigned char *buf,     /* Buffer to deserialize from */
  u32 serial_type,              /* Serial type to deserialize */
  Mem *pMem                     /* Memory cell to write value into */
){
  u64 x;
  u32 y;
  switch( serial_type ){
    case 10:   /* Reserved for future use */
    case 11:   /* Reserved for future use */
    case 0: {  /* NULL */
      pMem->flags = MEM_Null;
      break;
    }

    case 3: { /* 3-byte signed integer */
      pMem->u.i = THREE_BYTE_INT(buf);
      pMem->flags = MEM_Int;
      testcase( pMem->u.i<0 );
      return 3;
    }
    case 4: { /* 4-byte signed integer */
      y = FOUR_BYTE_UINT(buf);
      pMem->u.i = (i64)*(int*)&y;
      pMem->flags = MEM_Int;
      testcase( pMem->u.i<0 );
      return 4;
    }
    case 5: { /* 6-byte signed integer */
      pMem->u.i = FOUR_BYTE_UINT(buf+2) + (((i64)1)<<32)*TWO_BYTE_INT(buf);
      pMem->flags = MEM_Int;
      testcase( pMem->u.i<0 );
      return 6;
    }
    case 6:   /* 8-byte signed integer */
    case 7: { /* IEEE floating point */
#if !defined(NDEBUG) && !defined(SQLITE_OMIT_FLOATING_POINT)
      /* Verify that integers and floating point values use the same
      ** byte order.  Or, that if SQLITE_MIXED_ENDIAN_64BIT_FLOAT is
      ** defined that 64-bit floating point values really are mixed
      ** endian.
      */
      static const u64 t1 = ((u64)0x3ff00000)<<32;
      static const double r1 = 1.0;
      u64 t2 = t1;
      swapMixedEndianFloat(t2);
      assert( sizeof(r1)==sizeof(t2) && memcmp(&r1, &t2, sizeof(r1))==0 );
#endif
      x = FOUR_BYTE_UINT(buf);
      y = FOUR_BYTE_UINT(buf+4);
      x = (x<<32) | y;
      if( serial_type==6 ){
        pMem->u.i = *(i64*)&x;
        pMem->flags = MEM_Int;
        testcase( pMem->u.i<0 );
      }else{
        assert( sizeof(x)==8 && sizeof(pMem->r)==8 );
        swapMixedEndianFloat(x);
        memcpy(&pMem->r, &x, sizeof(x));
        pMem->flags = sqlite3IsNaN(pMem->r) ? MEM_Null : MEM_Real;
      }
      return 8;
    }
    case 8:    /* Integer 0 */
    case 9: {  /* Integer 1 */
      pMem->u.i = serial_type-8;
      pMem->flags = MEM_Int;
      return 0;
    }
    default: {
      static const u16 aFlag[] = { MEM_Blob|MEM_Ephem, MEM_Str|MEM_Ephem };
      u32 len = (serial_type-12)/2;
      pMem->z = (char *)buf;
      pMem->n = len;
      pMem->xDel = 0;
      pMem->flags = aFlag[serial_type&1];
      return len;
    }
  }
  return 0;
}

/*
** This routine is used to allocate sufficient space for an UnpackedRecord
** structure large enough to be used with sqlite3VdbeRecordUnpack() if
** the first argument is a pointer to KeyInfo structure pKeyInfo.
**
** The space is either allocated using sqlite3DbMallocRaw() or from within
** the unaligned buffer passed via the second and third arguments (presumably

/*
** This function compares two index or table record keys in the same way
** as the sqlite3VdbeRecordCompare() routine. Unlike VdbeRecordCompare(),
** this function deserializes and compares values using the
** sqlite3VdbeSerialGet() and sqlite3MemCompare() functions. It is used
** in assert() statements to ensure that the optimized code in
** sqlite3VdbeRecordCompare() returns results with these two primitives.



*/
static int vdbeRecordCompareDebug(
  int nKey1, const void *pKey1, /* Left key */
  const UnpackedRecord *pPKey2  /* Right key */

){
  u32 d1;            /* Offset into aKey[] of next data element */
  u32 idx1;          /* Offset into aKey[] of next header element */
  u32 szHdr1;        /* Number of bytes in header */
  int i = 0;
  int rc = 0;
  const unsigned char *aKey1 = (const unsigned char *)pKey1;
  KeyInfo *pKeyInfo;
  Mem mem1;

  pKeyInfo = pPKey2->pKeyInfo;

  mem1.enc = pKeyInfo->enc;
  mem1.db = pKeyInfo->db;
  /* mem1.flags = 0;  // Will be initialized by sqlite3VdbeSerialGet() */
  VVA_ONLY( mem1.zMalloc = 0; ) /* Only needed by assert() statements */

  /* Compilers may complain that mem1.u.i is potentially uninitialized.
  ** We could initialize it, as shown here, to silence those complaints.

    */
    rc = sqlite3MemCompare(&mem1, &pPKey2->aMem[i], pKeyInfo->aColl[i]);
    if( rc!=0 ){
      assert( mem1.zMalloc==0 );  /* See comment below */
      if( pKeyInfo->aSortOrder[i] ){
        rc = -rc;  /* Invert the result for DESC sort order. */
      }
      return rc;
    }
    i++;
  }while( idx1<szHdr1 && i<pPKey2->nField );

  /* No memory allocation is ever used on mem1.  Prove this using
  ** the following assert().  If the assert() fails, it indicates a
  ** memory leak and a need to call sqlite3VdbeMemRelease(&mem1).
  */
  assert( mem1.zMalloc==0 );

  /* rc==0 here means that one of the keys ran out of fields and
  ** all the fields up to that point were equal. Return the the default_rc
  ** value.  */
  return pPKey2->default_rc;








}
#endif

/*
** Both *pMem1 and *pMem2 contain string values. Compare the two values
** using the collation sequence pColl. As usual, return a negative , zero
** or positive value if *pMem1 is less than, equal to or greater than 
** *pMem2, respectively. Similar in spirit to "rc = (*pMem1) - (*pMem2);".
*/
static int vdbeCompareMemString(
  const Mem *pMem1,
  const Mem *pMem2,
  const CollSeq *pColl

){
  if( pMem1->enc==pColl->enc ){
    /* The strings are already in the correct encoding.  Call the
     ** comparison function directly */
    return pColl->xCmp(pColl->pUser,pMem1->n,pMem1->z,pMem2->n,pMem2->z);
  }else{
    int rc;

    v1 = sqlite3ValueText((sqlite3_value*)&c1, pColl->enc);
    n1 = v1==0 ? 0 : c1.n;
    v2 = sqlite3ValueText((sqlite3_value*)&c2, pColl->enc);
    n2 = v2==0 ? 0 : c2.n;
    rc = pColl->xCmp(pColl->pUser, n1, v1, n2, v2);
    sqlite3VdbeMemRelease(&c1);
    sqlite3VdbeMemRelease(&c2);

    return rc;
  }
}

/*
** Compare the values contained by the two memory cells, returning
** negative, zero or positive if pMem1 is less than, equal to, or greater

    /* The collation sequence must be defined at this point, even if
    ** the user deletes the collation sequence after the vdbe program is
    ** compiled (this was not always the case).
    */
    assert( !pColl || pColl->xCmp );

    if( pColl ){
      return vdbeCompareMemString(pMem1, pMem2, pColl);
    }
    /* If a NULL pointer was passed as the collate function, fall through
    ** to the blob case and use memcmp().  */
  }
 
  /* Both values must be blobs.  Compare using memcmp().  */
  rc = memcmp(pMem1->z, pMem2->z, (pMem1->n>pMem2->n)?pMem2->n:pMem1->n);

** If argument bSkip is non-zero, it is assumed that the caller has already
** determined that the first fields of the keys are equal.
**
** Key1 and Key2 do not have to contain the same number of fields. If all 
** fields that appear in both keys are equal, then pPKey2->default_rc is 
** returned.
**
** If database corruption is discovered, set pPKey2->isCorrupt to non-zero
** and return 0.


*/
SQLITE_PRIVATE int sqlite3VdbeRecordCompare(
  int nKey1, const void *pKey1,   /* Left key */
  UnpackedRecord *pPKey2,         /* Right key */
  int bSkip                       /* If true, skip the first field */
){
  u32 d1;                         /* Offset into aKey[] of next data element */

    d1 = szHdr1 + sqlite3VdbeSerialTypeLen(s1);
    i = 1;
    pRhs++;
  }else{
    idx1 = getVarint32(aKey1, szHdr1);
    d1 = szHdr1;
    if( d1>(unsigned)nKey1 ){ 
      pPKey2->isCorrupt = (u8)SQLITE_CORRUPT_BKPT;
      return 0;  /* Corruption */
    }
    i = 0;
  }

  VVA_ONLY( mem1.zMalloc = 0; ) /* Only needed by assert() statements */
  assert( pPKey2->pKeyInfo->nField+pPKey2->pKeyInfo->nXField>=pPKey2->nField 

      }else if( !(serial_type & 0x01) ){
        rc = +1;
      }else{
        mem1.n = (serial_type - 12) / 2;
        testcase( (d1+mem1.n)==(unsigned)nKey1 );
        testcase( (d1+mem1.n+1)==(unsigned)nKey1 );
        if( (d1+mem1.n) > (unsigned)nKey1 ){
          pPKey2->isCorrupt = (u8)SQLITE_CORRUPT_BKPT;
          return 0;                /* Corruption */
        }else if( pKeyInfo->aColl[i] ){
          mem1.enc = pKeyInfo->enc;
          mem1.db = pKeyInfo->db;
          mem1.flags = MEM_Str;
          mem1.z = (char*)&aKey1[d1];
          rc = vdbeCompareMemString(&mem1, pRhs, pKeyInfo->aColl[i]);


        }else{
          int nCmp = MIN(mem1.n, pRhs->n);
          rc = memcmp(&aKey1[d1], pRhs->z, nCmp);
          if( rc==0 ) rc = mem1.n - pRhs->n; 
        }
      }
    }

    /* RHS is a blob */
    else if( pRhs->flags & MEM_Blob ){
      getVarint32(&aKey1[idx1], serial_type);
      testcase( serial_type==12 );
      if( serial_type<12 || (serial_type & 0x01) ){
        rc = -1;
      }else{
        int nStr = (serial_type - 12) / 2;
        testcase( (d1+nStr)==(unsigned)nKey1 );
        testcase( (d1+nStr+1)==(unsigned)nKey1 );
        if( (d1+nStr) > (unsigned)nKey1 ){
          pPKey2->isCorrupt = (u8)SQLITE_CORRUPT_BKPT;
          return 0;                /* Corruption */
        }else{
          int nCmp = MIN(nStr, pRhs->n);
          rc = memcmp(&aKey1[d1], pRhs->z, nCmp);
          if( rc==0 ) rc = nStr - pRhs->n;
        }
      }
    }

    /* RHS is null */
    else{
      serial_type = aKey1[idx1];
      rc = (serial_type!=0);
    }

    if( rc!=0 ){
      if( pKeyInfo->aSortOrder[i] ){
        rc = -rc;
      }
      assert( CORRUPT_DB
          || (rc<0 && vdbeRecordCompareDebug(nKey1, pKey1, pPKey2)<0)
          || (rc>0 && vdbeRecordCompareDebug(nKey1, pKey1, pPKey2)>0)
          || pKeyInfo->db->mallocFailed
      );
      assert( mem1.zMalloc==0 );  /* See comment below */
      return rc;
    }

    i++;
    pRhs++;
    d1 += sqlite3VdbeSerialTypeLen(serial_type);
    idx1 += sqlite3VarintLen(serial_type);
  }while( idx1<(unsigned)szHdr1 && i<pPKey2->nField && d1<=(unsigned)nKey1 );

  /* No memory allocation is ever used on mem1.  Prove this using
  ** the following assert().  If the assert() fails, it indicates a
  ** memory leak and a need to call sqlite3VdbeMemRelease(&mem1).  */
  assert( mem1.zMalloc==0 );

  /* rc==0 here means that one or both of the keys ran out of fields and
  ** all the fields up to that point were equal. Return the the default_rc
  ** value.  */
  assert( CORRUPT_DB 
       || pPKey2->default_rc==vdbeRecordCompareDebug(nKey1, pKey1, pPKey2) 
       || pKeyInfo->db->mallocFailed
  );
  return pPKey2->default_rc;
}

/*
** This function is an optimized version of sqlite3VdbeRecordCompare() 

    res = sqlite3VdbeRecordCompare(nKey1, pKey1, pPKey2, 1);
  }else{
    /* The first fields of the two keys are equal and there are no trailing
    ** fields. Return pPKey2->default_rc in this case. */
    res = pPKey2->default_rc;
  }

  assert( (res==0 && vdbeRecordCompareDebug(nKey1, pKey1, pPKey2)==0)
       || (res<0 && vdbeRecordCompareDebug(nKey1, pKey1, pPKey2)<0)
       || (res>0 && vdbeRecordCompareDebug(nKey1, pKey1, pPKey2)>0)
       || CORRUPT_DB
  );
  return res;
}

/*
** This function is an optimized version of sqlite3VdbeRecordCompare() 
** that (a) the first field of pPKey2 is a string, that (b) the first field
** uses the collation sequence BINARY and (c) that the size-of-header varint 

  }else{
    int nCmp;
    int nStr;
    int szHdr = aKey1[0];

    nStr = (serial_type-12) / 2;
    if( (szHdr + nStr) > nKey1 ){
      pPKey2->isCorrupt = (u8)SQLITE_CORRUPT_BKPT;
      return 0;    /* Corruption */
    }
    nCmp = MIN( pPKey2->aMem[0].n, nStr );
    res = memcmp(&aKey1[szHdr], pPKey2->aMem[0].z, nCmp);

    if( res==0 ){
      res = nStr - pPKey2->aMem[0].n;

    }else if( res>0 ){
      res = pPKey2->r2;
    }else{
      res = pPKey2->r1;
    }
  }

  assert( (res==0 && vdbeRecordCompareDebug(nKey1, pKey1, pPKey2)==0)
       || (res<0 && vdbeRecordCompareDebug(nKey1, pKey1, pPKey2)<0)
       || (res>0 && vdbeRecordCompareDebug(nKey1, pKey1, pPKey2)>0)
       || CORRUPT_DB
       || pPKey2->pKeyInfo->db->mallocFailed
  );
  return res;
}

/*

static void setResultStrOrError(
  sqlite3_context *pCtx,  /* Function context */
  const char *z,          /* String pointer */
  int n,                  /* Bytes in string, or negative */
  u8 enc,                 /* Encoding of z.  0 for BLOBs */
  void (*xDel)(void*)     /* Destructor function */
){
  if( sqlite3VdbeMemSetStr(&pCtx->s, z, n, enc, xDel)==SQLITE_TOOBIG ){
    sqlite3_result_error_toobig(pCtx);
  }
}
SQLITE_API void sqlite3_result_blob(
  sqlite3_context *pCtx, 
  const void *z, 
  int n, 
  void (*xDel)(void *)
){
  assert( n>=0 );
  assert( sqlite3_mutex_held(pCtx->s.db->mutex) );
  setResultStrOrError(pCtx, z, n, 0, xDel);
}
SQLITE_API void sqlite3_result_double(sqlite3_context *pCtx, double rVal){
  assert( sqlite3_mutex_held(pCtx->s.db->mutex) );
  sqlite3VdbeMemSetDouble(&pCtx->s, rVal);
}
SQLITE_API void sqlite3_result_error(sqlite3_context *pCtx, const char *z, int n){
  assert( sqlite3_mutex_held(pCtx->s.db->mutex) );
  pCtx->isError = SQLITE_ERROR;
  pCtx->fErrorOrAux = 1;
  sqlite3VdbeMemSetStr(&pCtx->s, z, n, SQLITE_UTF8, SQLITE_TRANSIENT);
}
#ifndef SQLITE_OMIT_UTF16
SQLITE_API void sqlite3_result_error16(sqlite3_context *pCtx, const void *z, int n){
  assert( sqlite3_mutex_held(pCtx->s.db->mutex) );
  pCtx->isError = SQLITE_ERROR;
  pCtx->fErrorOrAux = 1;
  sqlite3VdbeMemSetStr(&pCtx->s, z, n, SQLITE_UTF16NATIVE, SQLITE_TRANSIENT);
}
#endif
SQLITE_API void sqlite3_result_int(sqlite3_context *pCtx, int iVal){
  assert( sqlite3_mutex_held(pCtx->s.db->mutex) );
  sqlite3VdbeMemSetInt64(&pCtx->s, (i64)iVal);
}
SQLITE_API void sqlite3_result_int64(sqlite3_context *pCtx, i64 iVal){
  assert( sqlite3_mutex_held(pCtx->s.db->mutex) );
  sqlite3VdbeMemSetInt64(&pCtx->s, iVal);
}
SQLITE_API void sqlite3_result_null(sqlite3_context *pCtx){
  assert( sqlite3_mutex_held(pCtx->s.db->mutex) );
  sqlite3VdbeMemSetNull(&pCtx->s);
}
SQLITE_API void sqlite3_result_text(
  sqlite3_context *pCtx, 
  const char *z, 
  int n,
  void (*xDel)(void *)
){
  assert( sqlite3_mutex_held(pCtx->s.db->mutex) );
  setResultStrOrError(pCtx, z, n, SQLITE_UTF8, xDel);
}
#ifndef SQLITE_OMIT_UTF16
SQLITE_API void sqlite3_result_text16(
  sqlite3_context *pCtx, 
  const void *z, 
  int n, 
  void (*xDel)(void *)
){
  assert( sqlite3_mutex_held(pCtx->s.db->mutex) );
  setResultStrOrError(pCtx, z, n, SQLITE_UTF16NATIVE, xDel);
}
SQLITE_API void sqlite3_result_text16be(
  sqlite3_context *pCtx, 
  const void *z, 
  int n, 
  void (*xDel)(void *)
){
  assert( sqlite3_mutex_held(pCtx->s.db->mutex) );
  setResultStrOrError(pCtx, z, n, SQLITE_UTF16BE, xDel);
}
SQLITE_API void sqlite3_result_text16le(
  sqlite3_context *pCtx, 
  const void *z, 
  int n, 
  void (*xDel)(void *)
){
  assert( sqlite3_mutex_held(pCtx->s.db->mutex) );
  setResultStrOrError(pCtx, z, n, SQLITE_UTF16LE, xDel);
}
#endif /* SQLITE_OMIT_UTF16 */
SQLITE_API void sqlite3_result_value(sqlite3_context *pCtx, sqlite3_value *pValue){
  assert( sqlite3_mutex_held(pCtx->s.db->mutex) );
  sqlite3VdbeMemCopy(&pCtx->s, pValue);
}
SQLITE_API void sqlite3_result_zeroblob(sqlite3_context *pCtx, int n){
  assert( sqlite3_mutex_held(pCtx->s.db->mutex) );
  sqlite3VdbeMemSetZeroBlob(&pCtx->s, n);
}
SQLITE_API void sqlite3_result_error_code(sqlite3_context *pCtx, int errCode){
  pCtx->isError = errCode;
  pCtx->fErrorOrAux = 1;
  if( pCtx->s.flags & MEM_Null ){
    sqlite3VdbeMemSetStr(&pCtx->s, sqlite3ErrStr(errCode), -1, 
                         SQLITE_UTF8, SQLITE_STATIC);
  }
}

/* Force an SQLITE_TOOBIG error. */
SQLITE_API void sqlite3_result_error_toobig(sqlite3_context *pCtx){
  assert( sqlite3_mutex_held(pCtx->s.db->mutex) );
  pCtx->isError = SQLITE_TOOBIG;
  pCtx->fErrorOrAux = 1;
  sqlite3VdbeMemSetStr(&pCtx->s, "string or blob too big", -1, 
                       SQLITE_UTF8, SQLITE_STATIC);
}

/* An SQLITE_NOMEM error. */
SQLITE_API void sqlite3_result_error_nomem(sqlite3_context *pCtx){
  assert( sqlite3_mutex_held(pCtx->s.db->mutex) );
  sqlite3VdbeMemSetNull(&pCtx->s);
  pCtx->isError = SQLITE_NOMEM;
  pCtx->fErrorOrAux = 1;
  pCtx->s.db->mallocFailed = 1;
}

/*
** This function is called after a transaction has been committed. It 
** invokes callbacks registered with sqlite3_wal_hook() as required.
*/
static int doWalCallbacks(sqlite3 *db){

  if( vdbeSafetyNotNull(v) ){
    return SQLITE_MISUSE_BKPT;
  }
  db = v->db;
  sqlite3_mutex_enter(db->mutex);
  v->doingRerun = 0;
  while( (rc = sqlite3Step(v))==SQLITE_SCHEMA
         && cnt++ < SQLITE_MAX_SCHEMA_RETRY

         && (rc2 = rc = sqlite3Reprepare(v))==SQLITE_OK ){

    sqlite3_reset(pStmt);
    v->doingRerun = 1;
    assert( v->expired==0 );
  }
  if( rc2!=SQLITE_OK ){
    /* 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

** returns a copy of the pointer to the database connection (the 1st
** parameter) of the sqlite3_create_function() and
** sqlite3_create_function16() routines that originally registered the
** application defined function.
*/
SQLITE_API sqlite3 *sqlite3_context_db_handle(sqlite3_context *p){
  assert( p && p->pFunc );
  return p->s.db;
}

/*
** Return the current time for a statement
*/
SQLITE_PRIVATE sqlite3_int64 sqlite3StmtCurrentTime(sqlite3_context *p){
  Vdbe *v = p->pVdbe;
  int rc;
  if( v->iCurrentTime==0 ){
    rc = sqlite3OsCurrentTimeInt64(p->s.db->pVfs, &v->iCurrentTime);
    if( rc ) v->iCurrentTime = 0;
  }
  return v->iCurrentTime;
}

/*
** The following is the implementation of an SQL function that always

  char *zErr;
  UNUSED_PARAMETER2(NotUsed, NotUsed2);
  zErr = sqlite3_mprintf(
      "unable to use function %s in the requested context", zName);
  sqlite3_result_error(context, zErr, -1);
  sqlite3_free(zErr);
}























/*
** Allocate or return the aggregate context for a user function.  A new
** context is allocated on the first call.  Subsequent calls return the
** same context that was returned on prior calls.
*/
SQLITE_API void *sqlite3_aggregate_context(sqlite3_context *p, int nByte){
  Mem *pMem;
  assert( p && p->pFunc && p->pFunc->xStep );
  assert( sqlite3_mutex_held(p->s.db->mutex) );
  pMem = p->pMem;
  testcase( nByte<0 );
  if( (pMem->flags & MEM_Agg)==0 ){
    if( nByte<=0 ){
      sqlite3VdbeMemReleaseExternal(pMem);
      pMem->flags = MEM_Null;
      pMem->z = 0;
    }else{
      sqlite3VdbeMemGrow(pMem, nByte, 0);
      pMem->flags = MEM_Agg;
      pMem->u.pDef = p->pFunc;
      if( pMem->z ){
        memset(pMem->z, 0, nByte);
      }
    }
  }
  return (void*)pMem->z;
}

/*
** Return the auxilary data pointer, if any, for the iArg'th argument to
** the user-function defined by pCtx.
*/
SQLITE_API void *sqlite3_get_auxdata(sqlite3_context *pCtx, int iArg){
  AuxData *pAuxData;

  assert( sqlite3_mutex_held(pCtx->s.db->mutex) );
  for(pAuxData=pCtx->pVdbe->pAuxData; pAuxData; pAuxData=pAuxData->pNext){
    if( pAuxData->iOp==pCtx->iOp && pAuxData->iArg==iArg ) break;
  }

  return (pAuxData ? pAuxData->pAux : 0);
}

  int iArg, 
  void *pAux, 
  void (*xDelete)(void*)
){
  AuxData *pAuxData;
  Vdbe *pVdbe = pCtx->pVdbe;

  assert( sqlite3_mutex_held(pCtx->s.db->mutex) );
  if( iArg<0 ) goto failed;

  for(pAuxData=pVdbe->pAuxData; pAuxData; pAuxData=pAuxData->pNext){
    if( pAuxData->iOp==pCtx->iOp && pAuxData->iArg==iArg ) break;
  }
  if( pAuxData==0 ){
    pAuxData = sqlite3DbMallocZero(pVdbe->db, sizeof(AuxData));

  pVm = (Vdbe *)pStmt;
  if( pVm && pVm->pResultSet!=0 && i<pVm->nResColumn && i>=0 ){
    sqlite3_mutex_enter(pVm->db->mutex);
    pOut = &pVm->pResultSet[i];
  }else{
    if( pVm && ALWAYS(pVm->db) ){
      sqlite3_mutex_enter(pVm->db->mutex);
      sqlite3Error(pVm->db, SQLITE_RANGE, 0);
    }
    pOut = (Mem*)columnNullValue();
  }
  return pOut;
}

/*

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--;
  pVar = &p->aVar[i];
  sqlite3VdbeMemRelease(pVar);
  pVar->flags = MEM_Null;
  sqlite3Error(p->db, SQLITE_OK, 0);

  /* If the bit corresponding to this variable in Vdbe.expmask is set, then 
  ** binding a new value to this variable invalidates the current query plan.
  **
  ** IMPLEMENTATION-OF: R-48440-37595 If the specific value bound to host
  ** parameter in the WHERE clause might influence the choice of query plan
  ** for a statement, then the statement will be automatically recompiled,

  if( rc==SQLITE_OK ){
    if( zData!=0 ){
      pVar = &p->aVar[i-1];
      rc = sqlite3VdbeMemSetStr(pVar, zData, nData, encoding, xDel);
      if( rc==SQLITE_OK && encoding!=0 ){
        rc = sqlite3VdbeChangeEncoding(pVar, ENC(p->db));
      }
      sqlite3Error(p->db, rc, 0);
      rc = sqlite3ApiExit(p->db, rc);
    }
    sqlite3_mutex_leave(p->db->mutex);
  }else if( xDel!=SQLITE_STATIC && xDel!=SQLITE_TRANSIENT ){
    xDel((void*)zData);
  }
  return rc;

#endif

/*
** Convert the given register into a string if it isn't one
** already. Return non-zero if a malloc() fails.
*/
#define Stringify(P, enc) \
   if(((P)->flags&(MEM_Str|MEM_Blob))==0 && sqlite3VdbeMemStringify(P,enc)) \
     { goto no_mem; }

/*
** An ephemeral string value (signified by the MEM_Ephem flag) contains
** a pointer to a dynamically allocated string where some other entity
** is responsible for deallocating that string.  Because the register
** does not control the string, it might be deleted without the register

}

/*
** Try to convert a value into a numeric representation if we can
** do so without loss of information.  In other words, if the string
** looks like a number, convert it into a number.  If it does not
** look like a number, leave it alone.









*/
static void applyNumericAffinity(Mem *pRec){
  double rValue;
  i64 iValue;
  u8 enc = pRec->enc;
  if( (pRec->flags&MEM_Str)==0 ) return;
  if( sqlite3AtoF(pRec->z, &rValue, pRec->n, enc)==0 ) return;
  if( 0==sqlite3Atoi64(pRec->z, &iValue, pRec->n, enc) ){
    pRec->u.i = iValue;
    pRec->flags |= MEM_Int;
  }else{
    pRec->r = rValue;
    pRec->flags |= MEM_Real;

  }
}
#define ApplyNumericAffinity(X)  \
   if(((X)->flags&(MEM_Real|MEM_Int))==0){applyNumericAffinity(X);}

/*
** Processing is determine by the affinity parameter:
**
** SQLITE_AFF_INTEGER:
** SQLITE_AFF_REAL:
** SQLITE_AFF_NUMERIC:

){
  if( affinity==SQLITE_AFF_TEXT ){
    /* Only attempt the conversion to TEXT if there is an integer or real
    ** representation (blob and NULL do not get converted) but no string
    ** representation.
    */
    if( 0==(pRec->flags&MEM_Str) && (pRec->flags&(MEM_Real|MEM_Int)) ){
      sqlite3VdbeMemStringify(pRec, enc);
    }
    pRec->flags &= ~(MEM_Real|MEM_Int);
  }else if( affinity!=SQLITE_AFF_NONE ){
    assert( affinity==SQLITE_AFF_INTEGER || affinity==SQLITE_AFF_REAL
             || affinity==SQLITE_AFF_NUMERIC );
    ApplyNumericAffinity(pRec);
    if( pRec->flags & MEM_Real ){


      sqlite3VdbeIntegerAffinity(pRec);

    }
  }
}

/*
** Try to convert the type of a function argument or a result column
** into a numeric representation.  Use either INTEGER or REAL whichever
** is appropriate.  But only do the conversion if it is possible without
** loss of information and return the revised type of the argument.
*/
SQLITE_API int sqlite3_value_numeric_type(sqlite3_value *pVal){
  int eType = sqlite3_value_type(pVal);
  if( eType==SQLITE_TEXT ){
    Mem *pMem = (Mem*)pVal;
    applyNumericAffinity(pMem);
    eType = sqlite3_value_type(pVal);
  }
  return eType;
}

/*
** Exported version of applyAffinity(). This one works on sqlite3_value*, 
** not the internal Mem* type.
*/
SQLITE_PRIVATE void sqlite3ValueApplyAffinity(
  sqlite3_value *pVal, 
  u8 affinity, 
  u8 enc
){
  applyAffinity((Mem *)pVal, affinity, enc);
}



















/*
** Return the numeric type for pMem, either MEM_Int or MEM_Real or both or
** none.  
**
** Unlike applyNumericAffinity(), this routine does not modify pMem->flags.
** But it does set pMem->r and pMem->u.i appropriately.
*/
static u16 numericType(Mem *pMem){
  if( pMem->flags & (MEM_Int|MEM_Real) ){
    return pMem->flags & (MEM_Int|MEM_Real);
  }
  if( pMem->flags & (MEM_Str|MEM_Blob) ){
    if( sqlite3AtoF(pMem->z, &pMem->r, pMem->n, pMem->enc)==0 ){
      return 0;
    }
    if( sqlite3Atoi64(pMem->z, &pMem->u.i, pMem->n, pMem->enc)==SQLITE_OK ){
      return MEM_Int;
    }
    return MEM_Real;
  }
  return 0;
}

#ifdef SQLITE_DEBUG
/*
** Write a nice string representation of the contents of cell pMem

    */
    assert( pOp->opflags==sqlite3OpcodeProperty[pOp->opcode] );
    if( pOp->opflags & OPFLG_OUT2_PRERELEASE ){
      assert( pOp->p2>0 );
      assert( pOp->p2<=(p->nMem-p->nCursor) );
      pOut = &aMem[pOp->p2];
      memAboutToChange(p, pOut);
      VdbeMemRelease(pOut);
      pOut->flags = MEM_Int;
    }

    /* Sanity checking on other operands */
#ifdef SQLITE_DEBUG
    if( (pOp->opflags & OPFLG_IN1)!=0 ){
      assert( pOp->p1>0 );

  u16 nullFlag;
  cnt = pOp->p3-pOp->p2;
  assert( pOp->p3<=(p->nMem-p->nCursor) );
  pOut->flags = nullFlag = pOp->p1 ? (MEM_Null|MEM_Cleared) : MEM_Null;
  while( cnt>0 ){
    pOut++;
    memAboutToChange(p, pOut);
    VdbeMemRelease(pOut);
    pOut->flags = nullFlag;
    cnt--;
  }
  break;
}

/* Opcode: SoftNull P1 * * * *

  pIn1 = &aMem[p1];
  pOut = &aMem[p2];
  do{
    assert( pOut<=&aMem[(p->nMem-p->nCursor)] );
    assert( pIn1<=&aMem[(p->nMem-p->nCursor)] );
    assert( memIsValid(pIn1) );
    memAboutToChange(p, pOut);
    VdbeMemRelease(pOut);
    zMalloc = pOut->zMalloc;
    memcpy(pOut, pIn1, sizeof(Mem));
#ifdef SQLITE_DEBUG
    if( pOut->pScopyFrom>=&aMem[p1] && pOut->pScopyFrom<&aMem[p1+pOp->p3] ){
      pOut->pScopyFrom += p1 - pOp->p2;
    }
#endif

  sqlite3_value **apVal;
  int n;

  n = pOp->p5;
  apVal = p->apArg;
  assert( apVal || n==0 );
  assert( pOp->p3>0 && pOp->p3<=(p->nMem-p->nCursor) );
  pOut = &aMem[pOp->p3];
  memAboutToChange(p, pOut);

  assert( n==0 || (pOp->p2>0 && pOp->p2+n<=(p->nMem-p->nCursor)+1) );
  assert( pOp->p3<pOp->p2 || pOp->p3>=pOp->p2+n );
  pArg = &aMem[pOp->p2];
  for(i=0; i<n; i++, pArg++){
    assert( memIsValid(pArg) );
    apVal[i] = pArg;
    Deephemeralize(pArg);
    REGISTER_TRACE(pOp->p2+i, pArg);
  }

  assert( pOp->p4type==P4_FUNCDEF );
  ctx.pFunc = pOp->p4.pFunc;
  ctx.iOp = pc;
  ctx.pVdbe = p;

  /* The output cell may already have a buffer allocated. Move
  ** the pointer to ctx.s so in case the user-function can use
  ** the already allocated buffer instead of allocating a new one.
  */
  memcpy(&ctx.s, pOut, sizeof(Mem));
  pOut->flags = MEM_Null;
  pOut->xDel = 0;
  pOut->zMalloc = 0;
  MemSetTypeFlag(&ctx.s, MEM_Null);

  ctx.fErrorOrAux = 0;
  if( ctx.pFunc->funcFlags & SQLITE_FUNC_NEEDCOLL ){
    assert( pOp>aOp );
    assert( pOp[-1].p4type==P4_COLLSEQ );
    assert( pOp[-1].opcode==OP_CollSeq );
    ctx.pColl = pOp[-1].p4.pColl;
  }
  db->lastRowid = lastRowid;
  (*ctx.pFunc->xFunc)(&ctx, n, apVal); /* IMP: R-24505-23230 */
  lastRowid = db->lastRowid;

  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(&ctx.s);
    goto no_mem;
  }

  /* If the function returned an error, throw an exception */
  if( ctx.fErrorOrAux ){
    if( ctx.isError ){
      sqlite3SetString(&p->zErrMsg, db, "%s", sqlite3_value_text(&ctx.s));
      rc = ctx.isError;
    }
    sqlite3VdbeDeleteAuxData(p, pc, pOp->p1);
  }

  /* Copy the result of the function into register P3 */
  sqlite3VdbeChangeEncoding(&ctx.s, encoding);
  assert( pOut->flags==MEM_Null );
  memcpy(pOut, &ctx.s, sizeof(Mem));
  if( sqlite3VdbeMemTooBig(pOut) ){
    goto too_big;
  }

#if 0
  /* The app-defined function has done something that as caused this
  ** statement to expire.  (Perhaps the function called sqlite3_exec()
  ** with a CREATE TABLE statement.)
  */
  if( p->expired ) rc = SQLITE_ABORT;
#endif

  REGISTER_TRACE(pOp->p3, pOut);
  UPDATE_MAX_BLOBSIZE(pOut);
  break;
}

/* Opcode: BitAnd P1 P2 P3 * *
** Synopsis:  r[P3]=r[P1]&r[P2]
**
** Take the bit-wise AND of the values in register P1 and P2 and

    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 sprintf().  Blob values are unchanged and
** are afterwards simply interpreted as text.
**
** A NULL value is not changed by this routine.  It remains NULL.
*/
case OP_ToText: {                  /* same as TK_TO_TEXT, in1 */
  pIn1 = &aMem[pOp->p1];
  memAboutToChange(p, pIn1);
  if( pIn1->flags & MEM_Null ) break;
  assert( MEM_Str==(MEM_Blob>>3) );
  pIn1->flags |= (pIn1->flags&MEM_Blob)>>3;
  applyAffinity(pIn1, SQLITE_AFF_TEXT, encoding);
  rc = ExpandBlob(pIn1);
  assert( pIn1->flags & MEM_Str || db->mallocFailed );
  pIn1->flags &= ~(MEM_Int|MEM_Real|MEM_Blob|MEM_Zero);
  UPDATE_MAX_BLOBSIZE(pIn1);
  break;
}

/* Opcode: ToBlob P1 * * * *
**
** Force the value in register P1 to be a BLOB.
** If the value is numeric, convert it to a string first.
** Strings are simply reinterpreted as blobs with no change
** to the underlying data.
**
** A NULL value is not changed by this routine.  It remains NULL.
*/
case OP_ToBlob: {                  /* same as TK_TO_BLOB, in1 */
  pIn1 = &aMem[pOp->p1];
  if( pIn1->flags & MEM_Null ) break;
  if( (pIn1->flags & MEM_Blob)==0 ){
    applyAffinity(pIn1, SQLITE_AFF_TEXT, encoding);
    assert( pIn1->flags & MEM_Str || db->mallocFailed );
    MemSetTypeFlag(pIn1, MEM_Blob);
  }else{
    pIn1->flags &= ~(MEM_TypeMask&~MEM_Blob);
  }
  UPDATE_MAX_BLOBSIZE(pIn1);
  break;
}

/* Opcode: ToNumeric P1 * * * *
**
** Force the value in register P1 to be numeric (either an
** integer or a floating-point number.)
** If the value is text or blob, try to convert it to an using the
** equivalent of atoi() or atof() and store 0 if no such conversion 
** is possible.
**
** A NULL value is not changed by this routine.  It remains NULL.
*/
case OP_ToNumeric: {                  /* same as TK_TO_NUMERIC, in1 */
  pIn1 = &aMem[pOp->p1];
  sqlite3VdbeMemNumerify(pIn1);
  break;
}
#endif /* SQLITE_OMIT_CAST */

/* Opcode: ToInt P1 * * * *
**
** Force the value in register P1 to be an integer.  If
** The value is currently a real number, drop its fractional part.
** If the value is text or blob, try to convert it to an integer using the
** equivalent of atoi() and store 0 if no such conversion is possible.
**
** A NULL value is not changed by this routine.  It remains NULL.
*/
case OP_ToInt: {                  /* same as TK_TO_INT, in1 */
  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];
  memAboutToChange(p, pIn1);
  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
** Synopsis: if r[P1]<r[P3] goto P2
**
** Compare the values in register P1 and P3.  If reg(P3)<reg(P1) then
** jump to address P2.  
**

  */
  assert( p2<pC->nHdrParsed );
  assert( rc==SQLITE_OK );
  assert( sqlite3VdbeCheckMemInvariants(pDest) );
  if( pC->szRow>=aOffset[p2+1] ){
    /* This is the common case where the desired content fits on the original
    ** page - where the content is not on an overflow page */
    VdbeMemRelease(pDest);
    sqlite3VdbeSerialGet(pC->aRow+aOffset[p2], aType[p2], pDest);
  }else{
    /* This branch happens only when content is on overflow pages */
    t = aType[p2];
    if( ((pOp->p5 & (OPFLAG_LENGTHARG|OPFLAG_TYPEOFARG))!=0
          && ((t>=12 && (t&1)==0) || (pOp->p5 & OPFLAG_TYPEOFARG)!=0))
     || (len = sqlite3VdbeSerialTypeLen(t))==0

      pCx->isTable = 1;
    }
  }
  pCx->isOrdered = (pOp->p5!=BTREE_UNORDERED);
  break;
}

/* Opcode: SorterOpen P1 P2 * P4 *
**
** This opcode works like OP_OpenEphemeral except that it opens
** a transient index that is specifically designed to sort large
** tables using an external merge-sort algorithm.




*/
case OP_SorterOpen: {
  VdbeCursor *pCx;

  assert( pOp->p1>=0 );
  assert( pOp->p2>=0 );
  pCx = allocateCursor(p, pOp->p1, pOp->p2, -1, 1);
  if( pCx==0 ) goto no_mem;
  pCx->pKeyInfo = pOp->p4.pKeyInfo;
  assert( pCx->pKeyInfo->db==db );
  assert( pCx->pKeyInfo->enc==ENC(db) );
  rc = sqlite3VdbeSorterInit(db, pCx);


















  break;
}

/* Opcode: OpenPseudo P1 P2 P3 * *
** Synopsis: P3 columns in r[P2]
**
** Open a new cursor that points to a fake table that contains a single

  pC->seekOp = pOp->opcode;
#endif
  if( pC->isTable ){
    /* The input value in P3 might be of any type: integer, real, string,
    ** blob, or NULL.  But it needs to be an integer before we can do
    ** the seek, so covert it. */
    pIn3 = &aMem[pOp->p3];

    ApplyNumericAffinity(pIn3);

    iKey = sqlite3VdbeIntValue(pIn3);
    pC->rowidIsValid = 0;

    /* If the P3 value could not be converted into an integer without
    ** loss of information, then special processing is required... */
    if( (pIn3->flags & MEM_Int)==0 ){
      if( (pIn3->flags & MEM_Real)==0 ){

  int nKeyCol;

  pC = p->apCsr[pOp->p1];
  assert( isSorter(pC) );
  assert( pOp->p4type==P4_INT32 );
  pIn3 = &aMem[pOp->p3];
  nKeyCol = pOp->p4.i;

  rc = sqlite3VdbeSorterCompare(pC, pIn3, nKeyCol, &res);
  VdbeBranchTaken(res!=0,2);
  if( res ){
    pc = pOp->p2-1;
  }
  break;
};

  assert( pC!=0 );
  assert( isSorter(pC)==(pOp->opcode==OP_SorterSort) );
  res = 1;
#ifdef SQLITE_DEBUG
  pC->seekOp = OP_Rewind;
#endif
  if( isSorter(pC) ){
    rc = sqlite3VdbeSorterRewind(db, pC, &res);
  }else{
    pCrsr = pC->pCursor;
    assert( pCrsr );
    rc = sqlite3BtreeFirst(pCrsr, &res);
    pC->deferredMoveto = 0;
    pC->cacheStatus = CACHE_STALE;
    pC->rowidIsValid = 0;

  pCrsr = pC->pCursor;
  if( pOp->p5 & OPFLAG_NCHANGE ) p->nChange++;
  assert( pCrsr!=0 );
  assert( pC->isTable==0 );
  rc = ExpandBlob(pIn2);
  if( rc==SQLITE_OK ){
    if( isSorter(pC) ){
      rc = sqlite3VdbeSorterWrite(db, pC, pIn2);
    }else{
      nKey = pIn2->n;
      zKey = pIn2->z;
      rc = sqlite3BtreeInsert(pCrsr, zKey, nKey, "", 0, 0, pOp->p3, 
          ((pOp->p5 & OPFLAG_USESEEKRESULT) ? pC->seekResult : 0)
          );
      assert( pC->deferredMoveto==0 );

** successors.
*/
case OP_AggStep: {
  int n;
  int i;
  Mem *pMem;
  Mem *pRec;

  sqlite3_context ctx;
  sqlite3_value **apVal;

  n = pOp->p5;
  assert( n>=0 );
  pRec = &aMem[pOp->p2];
  apVal = p->apArg;
  assert( apVal || n==0 );
  for(i=0; i<n; i++, pRec++){
    assert( memIsValid(pRec) );
    apVal[i] = pRec;
    memAboutToChange(p, pRec);
  }
  ctx.pFunc = pOp->p4.pFunc;
  assert( pOp->p3>0 && pOp->p3<=(p->nMem-p->nCursor) );
  ctx.pMem = pMem = &aMem[pOp->p3];
  pMem->n++;
  ctx.s.flags = MEM_Null;
  ctx.s.z = 0;
  ctx.s.zMalloc = 0;
  ctx.s.xDel = 0;
  ctx.s.db = db;

  ctx.isError = 0;
  ctx.pColl = 0;
  ctx.skipFlag = 0;
  if( ctx.pFunc->funcFlags & SQLITE_FUNC_NEEDCOLL ){
    assert( pOp>p->aOp );
    assert( pOp[-1].p4type==P4_COLLSEQ );
    assert( pOp[-1].opcode==OP_CollSeq );
    ctx.pColl = pOp[-1].p4.pColl;
  }
  (ctx.pFunc->xStep)(&ctx, n, apVal); /* IMP: R-24505-23230 */
  if( ctx.isError ){
    sqlite3SetString(&p->zErrMsg, db, "%s", sqlite3_value_text(&ctx.s));
    rc = ctx.isError;
  }
  if( ctx.skipFlag ){
    assert( pOp[-1].opcode==OP_CollSeq );
    i = pOp[-1].p1;
    if( i ) sqlite3VdbeMemSetInt64(&aMem[i], 1);
  }

  sqlite3VdbeMemRelease(&ctx.s);

  break;
}

/* Opcode: AggFinal P1 P2 * P4 *
** Synopsis: accum=r[P1] N=P2
**
** Execute the finalizer function for an aggregate.  P1 is

    sqlite3VdbeMemSetNull(pDest);
    break;
  }
  pVtab = pCur->pVtabCursor->pVtab;
  pModule = pVtab->pModule;
  assert( pModule->xColumn );
  memset(&sContext, 0, sizeof(sContext));

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

  rc = pModule->xColumn(pCur->pVtabCursor, &sContext, pOp->p2);
  sqlite3VtabImportErrmsg(p, pVtab);
  if( sContext.isError ){
    rc = 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 sContext.s (a Mem struct) is  released.
  */
  sqlite3VdbeChangeEncoding(&sContext.s, encoding);
  sqlite3VdbeMemMove(pDest, &sContext.s);
  REGISTER_TRACE(pOp->p3, pDest);
  UPDATE_MAX_BLOBSIZE(pDest);

  if( sqlite3VdbeMemTooBig(pDest) ){
    goto too_big;
  }
  break;

blob_open_out:
  if( rc==SQLITE_OK && db->mallocFailed==0 ){
    *ppBlob = (sqlite3_blob *)pBlob;
  }else{
    if( pBlob && pBlob->pStmt ) sqlite3VdbeFinalize((Vdbe *)pBlob->pStmt);
    sqlite3DbFree(db, pBlob);
  }
  sqlite3Error(db, rc, (zErr ? "%s" : 0), zErr);
  sqlite3DbFree(db, zErr);
  sqlite3ParserReset(pParse);
  sqlite3StackFree(db, pParse);
  rc = sqlite3ApiExit(db, rc);
  sqlite3_mutex_leave(db->mutex);
  return rc;
}

  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;
    sqlite3Error(db, SQLITE_ERROR, 0);
  }else if( v==0 ){
    /* If there is no statement handle, then the blob-handle has
    ** already been invalidated. Return SQLITE_ABORT in this case.
    */
    rc = SQLITE_ABORT;
  }else{
    /* Call either BtreeData() or BtreePutData(). If SQLITE_ABORT is

    ** already been invalidated. Return SQLITE_ABORT in this case.
    */
    rc = SQLITE_ABORT;
  }else{
    char *zErr;
    rc = blobSeekToRow(p, iRow, &zErr);
    if( rc!=SQLITE_OK ){
      sqlite3Error(db, rc, (zErr ? "%s" : 0), zErr);
      sqlite3DbFree(db, zErr);
    }
    assert( rc!=SQLITE_SCHEMA );
  }

  rc = sqlite3ApiExit(db, rc);
  assert( rc==SQLITE_OK || p->pStmt==0 );
  sqlite3_mutex_leave(db->mutex);
  return rc;
}

#endif /* #ifndef SQLITE_OMIT_INCRBLOB */

/************** End of vdbeblob.c ********************************************/
/************** Begin file vdbesort.c ****************************************/
/*
** 2011 July 9
**
** 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 contains code for the VdbeSorter object, used in concert with
** a VdbeCursor to sort large numbers of keys (as may be required, for
** example, by CREATE INDEX statements on tables too large to fit in main

** memory).



*/



typedef struct VdbeSorterIter VdbeSorterIter;









typedef struct SorterRecord SorterRecord;




























typedef struct FileWriter FileWriter;




/*
** NOTES ON DATA STRUCTURE USED FOR N-WAY MERGES:


































**
** As keys are added to the sorter, they are written to disk in a series
** of sorted packed-memory-arrays (PMAs). The size of each PMA is roughly
** the same as the cache-size allowed for temporary databases. In order



** to allow the caller to extract keys from the sorter in sorted order,















** all PMAs currently stored on disk must be merged together. This comment










** describes the data structure used to do so. The structure supports 








** merging any number of arrays in a single pass with no redundant comparison 

** operations.





















**

















** The aIter[] array contains an iterator for each of the PMAs being merged.
** An aIter[] iterator either points to a valid key or else is at EOF. For 

** the purposes of the paragraphs below, we assume that the array is actually 
** N elements in size, where N is the smallest power of 2 greater to or equal 
** to the number of iterators being merged. The extra aIter[] elements are 
** treated as if they are empty (always at EOF).
**
** The aTree[] array is also N elements in size. The value of N is stored in
** the VdbeSorter.nTree variable.
**
** The final (N/2) elements of aTree[] contain the results of comparing
** pairs of iterator keys together. Element i contains the result of 
** comparing aIter[2*i-N] and aIter[2*i-N+1]. Whichever key is smaller, the
** aTree element is set to the index of it. 
**
** For the purposes of this comparison, EOF is considered greater than any
** other key value. If the keys are equal (only possible with two EOF
** values), it doesn't matter which index is stored.
**
** The (N/4) elements of aTree[] that precede the final (N/2) described 
** above contains the index of the smallest of each block of 4 iterators.
** And so on. So that aTree[1] contains the index of the iterator that 
** currently points to the smallest key value. aTree[0] is unused.
**
** Example:
**
**     aIter[0] -> Banana
**     aIter[1] -> Feijoa
**     aIter[2] -> Elderberry
**     aIter[3] -> Currant
**     aIter[4] -> Grapefruit
**     aIter[5] -> Apple
**     aIter[6] -> Durian
**     aIter[7] -> EOF
**
**     aTree[] = { X, 5   0, 5    0, 3, 5, 6 }
**
** The current element is "Apple" (the value of the key indicated by 
** iterator 5). When the Next() operation is invoked, iterator 5 will
** be advanced to the next key in its segment. Say the next key is
** "Eggplant":
**
**     aIter[5] -> Eggplant
**
** The contents of aTree[] are updated first by comparing the new iterator
** 5 key to the current key of iterator 4 (still "Grapefruit"). The iterator
** 5 value is still smaller, so aTree[6] is set to 5. And so on up the tree.
** The value of iterator 6 - "Durian" - is now smaller than that of iterator
** 5, so aTree[3] is set to 6. Key 0 is smaller than key 6 (Banana<Durian),
** so the value written into element 1 of the array is 0. As follows:
**
**     aTree[] = { X, 0   0, 6    0, 3, 5, 6 }
**
** In other words, each time we advance to the next sorter element, log2(N)
** key comparison operations are required, where N is the number of segments
** being merged (rounded up to the next power of 2).
*/
struct VdbeSorter {
  i64 iWriteOff;                  /* Current write offset within file pTemp1 */

  i64 iReadOff;                   /* Current read offset within file pTemp1 */


  int nInMemory;                  /* Current size of pRecord list as PMA */

































  int nTree;                      /* Used size of aTree/aIter (power of 2) */



  int nPMA;                       /* Number of PMAs stored in pTemp1 */














  int mnPmaSize;                  /* Minimum PMA size, in bytes */
  int mxPmaSize;                  /* Maximum PMA size, in bytes.  0==no limit */
  VdbeSorterIter *aIter;          /* Array of iterators to merge */
  int *aTree;                     /* Current state of incremental merge */

  sqlite3_file *pTemp1;           /* PMA file 1 */
  SorterRecord *pRecord;          /* Head of in-memory record list */

  UnpackedRecord *pUnpacked;      /* Used to unpack keys */








};

/*















** The following type is an iterator for a PMA. It caches the current key in 





** variables nKey/aKey. If the iterator is at EOF, pFile==0.































*/
struct VdbeSorterIter {
  i64 iReadOff;                   /* Current read offset */
  i64 iEof;                       /* 1 byte past EOF for this iterator */
  int nAlloc;                     /* Bytes of space at aAlloc */
  int nKey;                       /* Number of bytes in key */
  sqlite3_file *pFile;            /* File iterator is reading from */
  u8 *aAlloc;                     /* Allocated space */
  u8 *aKey;                       /* Pointer to current key */
  u8 *aBuffer;                    /* Current read buffer */
  int nBuffer;                    /* Size of read buffer in bytes */
};

/*
** An instance of this structure is used to organize the stream of records

** being written to files by the merge-sort code into aligned, page-sized
** blocks.  Doing all I/O in aligned page-sized blocks helps I/O to go
** faster on many operating systems.


*/
struct FileWriter {
  int eFWErr;                     /* Non-zero if in an error state */
  u8 *aBuffer;                    /* Pointer to write buffer */
  int nBuffer;                    /* Size of write buffer in bytes */
  int iBufStart;                  /* First byte of buffer to write */
  int iBufEnd;                    /* Last byte of buffer to write */
  i64 iWriteOff;                  /* Offset of start of buffer in file */
  sqlite3_file *pFile;            /* File to write to */
};

/*




** A structure to store a single record. All in-memory records are connected
** together into a linked list headed at VdbeSorter.pRecord using the 
** SorterRecord.pNext pointer.









*/
struct SorterRecord {
  void *pVal;
  int nVal;

  SorterRecord *pNext;



};







/* Minimum allowable value for the VdbeSorter.nWorking variable */


#define SORTER_MIN_WORKING 10

/* Maximum number of segments to merge in a single pass. */
#define SORTER_MAX_MERGE_COUNT 16




/*
** Free all memory belonging to the VdbeSorterIter object passed as the second
** argument. All structure fields are set to zero before returning.
*/
static void vdbeSorterIterZero(sqlite3 *db, VdbeSorterIter *pIter){
  sqlite3DbFree(db, pIter->aAlloc);
  sqlite3DbFree(db, pIter->aBuffer);


  memset(pIter, 0, sizeof(VdbeSorterIter));
}

/*
** Read nByte bytes of data from the stream of data iterated by object p.
** If successful, set *ppOut to point to a buffer containing the data
** and return SQLITE_OK. Otherwise, if an error occurs, return an SQLite
** error code.
**
** The buffer indicated by *ppOut may only be considered valid until the
** next call to this function.
*/
static int vdbeSorterIterRead(
  sqlite3 *db,                    /* Database handle (for malloc) */
  VdbeSorterIter *p,              /* Iterator */
  int nByte,                      /* Bytes of data to read */
  u8 **ppOut                      /* OUT: Pointer to buffer containing data */
){
  int iBuf;                       /* Offset within buffer to read from */
  int nAvail;                     /* Bytes of data available in buffer */







  assert( p->aBuffer );

  /* If there is no more data to be read from the buffer, read the next 
  ** p->nBuffer bytes of data from the file into it. Or, if there are less
  ** than p->nBuffer bytes remaining in the PMA, read all remaining data.  */
  iBuf = p->iReadOff % p->nBuffer;
  if( iBuf==0 ){
    int nRead;                    /* Bytes to read from disk */
    int rc;                       /* sqlite3OsRead() return code */

    /* Determine how many bytes of data to read. */
    if( (p->iEof - p->iReadOff) > (i64)p->nBuffer ){
      nRead = p->nBuffer;
    }else{
      nRead = (int)(p->iEof - p->iReadOff);
    }
    assert( nRead>0 );

    /* Read data from the file. Return early if an error occurs. */
    rc = sqlite3OsRead(p->pFile, p->aBuffer, nRead, p->iReadOff);
    assert( rc!=SQLITE_IOERR_SHORT_READ );
    if( rc!=SQLITE_OK ) return rc;
  }
  nAvail = p->nBuffer - iBuf; 

  if( nByte<=nAvail ){
    /* The requested data is available in the in-memory buffer. In this
    ** case there is no need to make a copy of the data, just return a 
    ** pointer into the buffer to the caller.  */
    *ppOut = &p->aBuffer[iBuf];
    p->iReadOff += nByte;
  }else{
    /* The requested data is not all available in the in-memory buffer.
    ** In this case, allocate space at p->aAlloc[] to copy the requested
    ** range into. Then return a copy of pointer p->aAlloc to the caller.  */
    int nRem;                     /* Bytes remaining to copy */

    /* Extend the p->aAlloc[] allocation if required. */
    if( p->nAlloc<nByte ){

      int nNew = p->nAlloc*2;
      while( nByte>nNew ) nNew = nNew*2;
      p->aAlloc = sqlite3DbReallocOrFree(db, p->aAlloc, nNew);
      if( !p->aAlloc ) return SQLITE_NOMEM;
      p->nAlloc = nNew;

    }

    /* Copy as much data as is available in the buffer into the start of
    ** p->aAlloc[].  */
    memcpy(p->aAlloc, &p->aBuffer[iBuf], nAvail);
    p->iReadOff += nAvail;
    nRem = nByte - nAvail;

    /* The following loop copies up to p->nBuffer bytes per iteration into
    ** the p->aAlloc[] buffer.  */
    while( nRem>0 ){
      int rc;                     /* vdbeSorterIterRead() return code */
      int nCopy;                  /* Number of bytes to copy */
      u8 *aNext;                  /* Pointer to buffer to copy data from */

      nCopy = nRem;
      if( nRem>p->nBuffer ) nCopy = p->nBuffer;
      rc = vdbeSorterIterRead(db, p, nCopy, &aNext);
      if( rc!=SQLITE_OK ) return rc;
      assert( aNext!=p->aAlloc );
      memcpy(&p->aAlloc[nByte - nRem], aNext, nCopy);
      nRem -= nCopy;
    }

    *ppOut = p->aAlloc;
  }

  return SQLITE_OK;
}

/*
** Read a varint from the stream of data accessed by p. Set *pnOut to
** the value read.
*/
static int vdbeSorterIterVarint(sqlite3 *db, VdbeSorterIter *p, u64 *pnOut){
  int iBuf;




  iBuf = p->iReadOff % p->nBuffer;
  if( iBuf && (p->nBuffer-iBuf)>=9 ){
    p->iReadOff += sqlite3GetVarint(&p->aBuffer[iBuf], pnOut);
  }else{
    u8 aVarint[16], *a;
    int i = 0, rc;
    do{
      rc = vdbeSorterIterRead(db, p, 1, &a);
      if( rc ) return rc;
      aVarint[(i++)&0xf] = a[0];
    }while( (a[0]&0x80)!=0 );
    sqlite3GetVarint(aVarint, pnOut);

  }

  return SQLITE_OK;
}


/*



** Advance iterator pIter to the next key in its PMA. Return SQLITE_OK if

** no error occurs, or an SQLite error code if one does.

*/
static int vdbeSorterIterNext(
  sqlite3 *db,                    /* Database handle (for sqlite3DbMalloc() ) */
  VdbeSorterIter *pIter           /* Iterator to advance */
){
  int rc;                         /* Return Code */
  u64 nRec = 0;                   /* Size of record in bytes */

  if( pIter->iReadOff>=pIter->iEof ){
    /* This is an EOF condition */
    vdbeSorterIterZero(db, pIter);
    return SQLITE_OK;
  }

  rc = vdbeSorterIterVarint(db, pIter, &nRec);

  if( rc==SQLITE_OK ){
    pIter->nKey = (int)nRec;
    rc = vdbeSorterIterRead(db, pIter, (int)nRec, &pIter->aKey);
  }

  return rc;
}

/*
** Initialize iterator pIter to scan through the PMA stored in file pFile
** starting at offset iStart and ending at offset iEof-1. This function 
** leaves the iterator pointing to the first key in the PMA (or EOF if the 
** PMA is empty).


*/
static int vdbeSorterIterInit(
  sqlite3 *db,                    /* Database handle */

  const VdbeSorter *pSorter,      /* Sorter object */
  i64 iStart,                     /* Start offset in pFile */
  VdbeSorterIter *pIter,          /* Iterator to populate */
  i64 *pnByte                     /* IN/OUT: Increment this value by PMA size */
){
  int rc = SQLITE_OK;
  int nBuf;


  nBuf = sqlite3BtreeGetPageSize(db->aDb[0].pBt);




  assert( pSorter->iWriteOff>iStart );
  assert( pIter->aAlloc==0 );
  assert( pIter->aBuffer==0 );
  pIter->pFile = pSorter->pTemp1;
  pIter->iReadOff = iStart;
  pIter->nAlloc = 128;
  pIter->aAlloc = (u8 *)sqlite3DbMallocRaw(db, pIter->nAlloc);
  pIter->nBuffer = nBuf;
  pIter->aBuffer = (u8 *)sqlite3DbMallocRaw(db, nBuf);





  if( !pIter->aBuffer ){

    rc = SQLITE_NOMEM;
  }else{
    int iBuf;

    iBuf = iStart % nBuf;
    if( iBuf ){
      int nRead = nBuf - iBuf;
      if( (iStart + nRead) > pSorter->iWriteOff ){
        nRead = (int)(pSorter->iWriteOff - iStart);
      }
      rc = sqlite3OsRead(
          pSorter->pTemp1, &pIter->aBuffer[iBuf], nRead, iStart
      );

    }

    if( rc==SQLITE_OK ){


      u64 nByte;                       /* Size of PMA in bytes */







      pIter->iEof = pSorter->iWriteOff;
      rc = vdbeSorterIterVarint(db, pIter, &nByte);
      pIter->iEof = pIter->iReadOff + nByte;











      *pnByte += nByte;





    }
  }

  if( rc==SQLITE_OK ){







    rc = vdbeSorterIterNext(db, pIter);




































  }
  return rc;
}


/*
** Compare key1 (buffer pKey1, size nKey1 bytes) with key2 (buffer pKey2, 
** size nKey2 bytes).  Argument pKeyInfo supplies the collation functions
** used by the comparison. If an error occurs, return an SQLite error code.
** Otherwise, return SQLITE_OK and set *pRes to a negative, zero or positive
** value, depending on whether key1 is smaller, equal to or larger than key2.
**


** If the bOmitRowid argument is non-zero, assume both keys end in a rowid
** field. For the purposes of the comparison, ignore it. Also, if bOmitRowid
** is true and key1 contains even a single NULL value, it is considered to
** be less than key2. Even if key2 also contains NULL values.
**
** If pKey2 is passed a NULL pointer, then it is assumed that the pCsr->aSpace
** has been allocated and contains an unpacked record that is used as key2.


*/
static void vdbeSorterCompare(
  const VdbeCursor *pCsr,         /* Cursor object (for pKeyInfo) */
  int nKeyCol,                    /* Num of columns. 0 means "all" */
  const void *pKey1, int nKey1,   /* Left side of comparison */
  const void *pKey2, int nKey2,   /* Right side of comparison */
  int *pRes                       /* OUT: Result of comparison */
){
  KeyInfo *pKeyInfo = pCsr->pKeyInfo;
  VdbeSorter *pSorter = pCsr->pSorter;
  UnpackedRecord *r2 = pSorter->pUnpacked;
  int i;

  if( pKey2 ){
    sqlite3VdbeRecordUnpack(pKeyInfo, nKey2, pKey2, r2);
  }

  if( nKeyCol ){
    r2->nField = nKeyCol;
    for(i=0; i<nKeyCol; i++){
      if( r2->aMem[i].flags & MEM_Null ){
        *pRes = -1;
        return;
      }
    }
    assert( r2->default_rc==0 );
  }

  *pRes = sqlite3VdbeRecordCompare(nKey1, pKey1, r2, 0);
}

/*
** This function is called to compare two iterator keys when merging 
** multiple b-tree segments. Parameter iOut is the index of the aTree[] 
** value to recalculate.
*/
static int vdbeSorterDoCompare(const VdbeCursor *pCsr, int iOut){
  VdbeSorter *pSorter = pCsr->pSorter;
  int i1;
  int i2;
  int iRes;
  VdbeSorterIter *p1;
  VdbeSorterIter *p2;

  assert( iOut<pSorter->nTree && iOut>0 );

  if( iOut>=(pSorter->nTree/2) ){
    i1 = (iOut - pSorter->nTree/2) * 2;
    i2 = i1 + 1;
  }else{
    i1 = pSorter->aTree[iOut*2];
    i2 = pSorter->aTree[iOut*2+1];
  }

  p1 = &pSorter->aIter[i1];
  p2 = &pSorter->aIter[i2];

  if( p1->pFile==0 ){
    iRes = i2;
  }else if( p2->pFile==0 ){
    iRes = i1;
  }else{
    int res;
    assert( pCsr->pSorter->pUnpacked!=0 );  /* allocated in vdbeSorterMerge() */
    vdbeSorterCompare(
        pCsr, 0, p1->aKey, p1->nKey, p2->aKey, p2->nKey, &res
    );
    if( res<=0 ){
      iRes = i1;
    }else{
      iRes = i2;
    }
  }

  pSorter->aTree[iOut] = iRes;
  return SQLITE_OK;
}

/*
** Initialize the temporary index cursor just opened as a sorter cursor.
















*/
SQLITE_PRIVATE int sqlite3VdbeSorterInit(sqlite3 *db, VdbeCursor *pCsr){




  int pgsz;                       /* Page size of main database */

  int mxCache;                    /* Cache size */
  VdbeSorter *pSorter;            /* The new sorter */


  char *d;                        /* Dummy */
























  assert( pCsr->pKeyInfo && pCsr->pBt==0 );




  pCsr->pSorter = pSorter = sqlite3DbMallocZero(db, sizeof(VdbeSorter));
  if( pSorter==0 ){
    return SQLITE_NOMEM;
  }
  
  pSorter->pUnpacked = sqlite3VdbeAllocUnpackedRecord(pCsr->pKeyInfo, 0, 0, &d);



  if( pSorter->pUnpacked==0 ) return SQLITE_NOMEM;

  assert( pSorter->pUnpacked==(UnpackedRecord *)d );





  if( !sqlite3TempInMemory(db) ){
    pgsz = sqlite3BtreeGetPageSize(db->aDb[0].pBt);
    pSorter->mnPmaSize = SORTER_MIN_WORKING * pgsz;
    mxCache = db->aDb[0].pSchema->cache_size;
    if( mxCache<SORTER_MIN_WORKING ) mxCache = SORTER_MIN_WORKING;
    pSorter->mxPmaSize = mxCache * pgsz;
  }















  return SQLITE_OK;
}


/*
** Free the list of sorted records starting at pRecord.
*/
static void vdbeSorterRecordFree(sqlite3 *db, SorterRecord *pRecord){
  SorterRecord *p;
  SorterRecord *pNext;
  for(p=pRecord; p; p=pNext){
    pNext = p->pNext;
    sqlite3DbFree(db, p);
  }
}































































































































































































/*
** Reset a sorting cursor back to its original empty state.
*/
SQLITE_PRIVATE void sqlite3VdbeSorterReset(sqlite3 *db, VdbeSorter *pSorter){
  if( pSorter->aIter ){
    int i;



    for(i=0; i<pSorter->nTree; i++){
      vdbeSorterIterZero(db, &pSorter->aIter[i]);
    }
    sqlite3DbFree(db, pSorter->aIter);
    pSorter->aIter = 0;
  }
  if( pSorter->pTemp1 ){
    sqlite3OsCloseFree(pSorter->pTemp1);
    pSorter->pTemp1 = 0;



  }

  vdbeSorterRecordFree(db, pSorter->pRecord);

  pSorter->pRecord = 0;
  pSorter->iWriteOff = 0;
  pSorter->iReadOff = 0;
  pSorter->nInMemory = 0;
  pSorter->nTree = 0;
  pSorter->nPMA = 0;
  pSorter->aTree = 0;
}


/*
** Free any cursor components allocated by sqlite3VdbeSorterXXX routines.
*/
SQLITE_PRIVATE void sqlite3VdbeSorterClose(sqlite3 *db, VdbeCursor *pCsr){
  VdbeSorter *pSorter = pCsr->pSorter;
  if( pSorter ){
    sqlite3VdbeSorterReset(db, pSorter);
    sqlite3DbFree(db, pSorter->pUnpacked);
    sqlite3DbFree(db, pSorter);
    pCsr->pSorter = 0;
  }
}


/*























** Allocate space for a file-handle and open a temporary file. If successful,
** set *ppFile to point to the malloc'd file-handle and return SQLITE_OK.
** Otherwise, set *ppFile to 0 and return an SQLite error code.
*/
static int vdbeSorterOpenTempFile(sqlite3 *db, sqlite3_file **ppFile){




  int dummy;
  return sqlite3OsOpenMalloc(db->pVfs, 0, ppFile,
      SQLITE_OPEN_TEMP_JOURNAL |
      SQLITE_OPEN_READWRITE    | SQLITE_OPEN_CREATE |
      SQLITE_OPEN_EXCLUSIVE    | SQLITE_OPEN_DELETEONCLOSE, &dummy
  );





}
























/*
** Merge the two sorted lists p1 and p2 into a single list.
** Set *ppOut to the head of the new list.
*/
static void vdbeSorterMerge(
  const VdbeCursor *pCsr,         /* For pKeyInfo */
  SorterRecord *p1,               /* First list to merge */
  SorterRecord *p2,               /* Second list to merge */
  SorterRecord **ppOut            /* OUT: Head of merged list */
){
  SorterRecord *pFinal = 0;
  SorterRecord **pp = &pFinal;
  void *pVal2 = p2 ? p2->pVal : 0;

  while( p1 && p2 ){
    int res;
    vdbeSorterCompare(pCsr, 0, p1->pVal, p1->nVal, pVal2, p2->nVal, &res);
    if( res<=0 ){
      *pp = p1;
      pp = &p1->pNext;
      p1 = p1->pNext;
      pVal2 = 0;
    }else{
      *pp = p2;
       pp = &p2->pNext;
      p2 = p2->pNext;
      if( p2==0 ) break;
      pVal2 = p2->pVal;
    }
  }
  *pp = p1 ? p1 : p2;
  *ppOut = pFinal;
}

/*
** Sort the linked list of records headed at pCsr->pRecord. Return SQLITE_OK
** if successful, or an SQLite error code (i.e. SQLITE_NOMEM) if an error
** occurs.
*/
static int vdbeSorterSort(const VdbeCursor *pCsr){
  int i;
  SorterRecord **aSlot;
  SorterRecord *p;

  VdbeSorter *pSorter = pCsr->pSorter;



  aSlot = (SorterRecord **)sqlite3MallocZero(64 * sizeof(SorterRecord *));
  if( !aSlot ){
    return SQLITE_NOMEM;
  }

  p = pSorter->pRecord;
  while( p ){
    SorterRecord *pNext = p->pNext;


    p->pNext = 0;









    for(i=0; aSlot[i]; i++){
      vdbeSorterMerge(pCsr, p, aSlot[i], &p);
      aSlot[i] = 0;
    }
    aSlot[i] = p;
    p = pNext;
  }

  p = 0;
  for(i=0; i<64; i++){
    vdbeSorterMerge(pCsr, p, aSlot[i], &p);
  }
  pSorter->pRecord = p;

  sqlite3_free(aSlot);
  return SQLITE_OK;



}

/*
** Initialize a file-writer object.
*/
static void fileWriterInit(
  sqlite3 *db,                    /* Database (for malloc) */
  sqlite3_file *pFile,            /* File to write to */
  FileWriter *p,                  /* Object to populate */
  i64 iStart                      /* Offset of pFile to begin writing at */
){
  int nBuf = sqlite3BtreeGetPageSize(db->aDb[0].pBt);

  memset(p, 0, sizeof(FileWriter));
  p->aBuffer = (u8 *)sqlite3DbMallocRaw(db, nBuf);
  if( !p->aBuffer ){
    p->eFWErr = SQLITE_NOMEM;
  }else{
    p->iBufEnd = p->iBufStart = (iStart % nBuf);
    p->iWriteOff = iStart - p->iBufStart;
    p->nBuffer = nBuf;
    p->pFile = pFile;
  }
}

/*
** Write nData bytes of data to the file-write object. Return SQLITE_OK
** if successful, or an SQLite error code if an error occurs.
*/
static void fileWriterWrite(FileWriter *p, u8 *pData, int nData){
  int nRem = nData;
  while( nRem>0 && p->eFWErr==0 ){
    int nCopy = nRem;
    if( nCopy>(p->nBuffer - p->iBufEnd) ){
      nCopy = p->nBuffer - p->iBufEnd;
    }

    memcpy(&p->aBuffer[p->iBufEnd], &pData[nData-nRem], nCopy);
    p->iBufEnd += nCopy;
    if( p->iBufEnd==p->nBuffer ){
      p->eFWErr = sqlite3OsWrite(p->pFile, 
          &p->aBuffer[p->iBufStart], p->iBufEnd - p->iBufStart, 
          p->iWriteOff + p->iBufStart
      );
      p->iBufStart = p->iBufEnd = 0;
      p->iWriteOff += p->nBuffer;
    }
    assert( p->iBufEnd<p->nBuffer );

    nRem -= nCopy;
  }
}

/*
** Flush any buffered data to disk and clean up the file-writer object.
** The results of using the file-writer after this call are undefined.
** Return SQLITE_OK if flushing the buffered data succeeds or is not 
** required. Otherwise, return an SQLite error code.
**
** Before returning, set *piEof to the offset immediately following the
** last byte written to the file.
*/
static int fileWriterFinish(sqlite3 *db, FileWriter *p, i64 *piEof){
  int rc;
  if( p->eFWErr==0 && ALWAYS(p->aBuffer) && p->iBufEnd>p->iBufStart ){
    p->eFWErr = sqlite3OsWrite(p->pFile, 
        &p->aBuffer[p->iBufStart], p->iBufEnd - p->iBufStart, 
        p->iWriteOff + p->iBufStart
    );
  }
  *piEof = (p->iWriteOff + p->iBufEnd);
  sqlite3DbFree(db, p->aBuffer);
  rc = p->eFWErr;
  memset(p, 0, sizeof(FileWriter));
  return rc;
}

/*
** Write value iVal encoded as a varint to the file-write object. Return 
** SQLITE_OK if successful, or an SQLite error code if an error occurs.
*/
static void fileWriterWriteVarint(FileWriter *p, u64 iVal){
  int nByte; 
  u8 aByte[10];
  nByte = sqlite3PutVarint(aByte, iVal);
  fileWriterWrite(p, aByte, nByte);
}

/*
** Write the current contents of the in-memory linked-list to a PMA. Return

** SQLITE_OK if successful, or an SQLite error code otherwise.
**
** The format of a PMA is:
**
**     * A varint. This varint contains the total number of bytes of content
**       in the PMA (not including the varint itself).
**
**     * One or more records packed end-to-end in order of ascending keys. 
**       Each record consists of a varint followed by a blob of data (the 
**       key). The varint is the number of bytes in the blob of data.
*/
static int vdbeSorterListToPMA(sqlite3 *db, const VdbeCursor *pCsr){

  int rc = SQLITE_OK;             /* Return code */

  VdbeSorter *pSorter = pCsr->pSorter;

  FileWriter writer;





  memset(&writer, 0, sizeof(FileWriter));



  if( pSorter->nInMemory==0 ){



    assert( pSorter->pRecord==0 );
    return rc;
  }



  rc = vdbeSorterSort(pCsr);

  /* If the first temporary PMA file has not been opened, open it now. */

  if( rc==SQLITE_OK && pSorter->pTemp1==0 ){
    rc = vdbeSorterOpenTempFile(db, &pSorter->pTemp1);
    assert( rc!=SQLITE_OK || pSorter->pTemp1 );
    assert( pSorter->iWriteOff==0 );
    assert( pSorter->nPMA==0 );
  }

  if( rc==SQLITE_OK ){
    SorterRecord *p;
    SorterRecord *pNext = 0;

    fileWriterInit(db, pSorter->pTemp1, &writer, pSorter->iWriteOff);

    pSorter->nPMA++;
    fileWriterWriteVarint(&writer, pSorter->nInMemory);
    for(p=pSorter->pRecord; p; p=pNext){






















































































      pNext = p->pNext;


      fileWriterWriteVarint(&writer, p->nVal);













      fileWriterWrite(&writer, p->pVal, p->nVal);













      sqlite3DbFree(db, p);



    }
































    pSorter->pRecord = p;








    rc = fileWriterFinish(db, &writer, &pSorter->iWriteOff);


  }

  return rc;

}

/*
** Add a record to the sorter.
*/
SQLITE_PRIVATE int sqlite3VdbeSorterWrite(
  sqlite3 *db,                    /* Database handle */
  const VdbeCursor *pCsr,               /* Sorter cursor */
  Mem *pVal                       /* Memory cell containing record */
){
  VdbeSorter *pSorter = pCsr->pSorter;
  int rc = SQLITE_OK;             /* Return Code */
  SorterRecord *pNew;             /* New list element */

  assert( pSorter );
  pSorter->nInMemory += sqlite3VarintLen(pVal->n) + pVal->n;


  pNew = (SorterRecord *)sqlite3DbMallocRaw(db, pVal->n + sizeof(SorterRecord));
  if( pNew==0 ){
    rc = SQLITE_NOMEM;
  }else{
    pNew->pVal = (void *)&pNew[1];
    memcpy(pNew->pVal, pVal->z, pVal->n);
    pNew->nVal = pVal->n;
    pNew->pNext = pSorter->pRecord;
    pSorter->pRecord = pNew;
  }




  /* See if the contents of the sorter should now be written out. They



  ** are written out when either of the following are true:
  **
  **   * The total memory allocated for the in-memory list is greater 
  **     than (page-size * cache-size), or
  **
  **   * The total memory allocated for the in-memory list is greater 
  **     than (page-size * 10) and sqlite3HeapNearlyFull() returns true.
  */


  if( rc==SQLITE_OK && pSorter->mxPmaSize>0 && (
        (pSorter->nInMemory>pSorter->mxPmaSize)




     || (pSorter->nInMemory>pSorter->mnPmaSize && sqlite3HeapNearlyFull())
  )){







































#ifdef SQLITE_DEBUG

    i64 nExpect = pSorter->iWriteOff




















































































































































                + sqlite3VarintLen(pSorter->nInMemory)









                + pSorter->nInMemory;
#endif


































































    rc = vdbeSorterListToPMA(db, pCsr);


























    pSorter->nInMemory = 0;




















    assert( rc!=SQLITE_OK || (nExpect==pSorter->iWriteOff) );
  }


































































































  return rc;
}
































































































































































































































/*
** Helper function for sqlite3VdbeSorterRewind(). 






*/
static int vdbeSorterInitMerge(






  sqlite3 *db,                    /* Database handle */


















































  const VdbeCursor *pCsr,         /* Cursor handle for this sorter */





  i64 *pnByte                     /* Sum of bytes in all opened PMAs */
){






  VdbeSorter *pSorter = pCsr->pSorter;
  int rc = SQLITE_OK;             /* Return code */
  int i;                          /* Used to iterator through aIter[] */
  i64 nByte = 0;                  /* Total bytes in all opened PMAs */

  /* Initialize the iterators. */
  for(i=0; i<SORTER_MAX_MERGE_COUNT; i++){
    VdbeSorterIter *pIter = &pSorter->aIter[i];
    rc = vdbeSorterIterInit(db, pSorter, pSorter->iReadOff, pIter, &nByte);
    pSorter->iReadOff = pIter->iEof;
    assert( rc!=SQLITE_OK || pSorter->iReadOff<=pSorter->iWriteOff );
    if( rc!=SQLITE_OK || pSorter->iReadOff>=pSorter->iWriteOff ) break;
  }

  /* Initialize the aTree[] array. */
  for(i=pSorter->nTree-1; rc==SQLITE_OK && i>0; i--){
    rc = vdbeSorterDoCompare(pCsr, i);
  }

  *pnByte = nByte;
  return rc;
}

/*
** Once the sorter has been populated, this function is called to prepare
** for iterating through its contents in sorted order.
*/
SQLITE_PRIVATE int sqlite3VdbeSorterRewind(sqlite3 *db, const VdbeCursor *pCsr, int *pbEof){
  VdbeSorter *pSorter = pCsr->pSorter;
  int rc;                         /* Return code */
  sqlite3_file *pTemp2 = 0;       /* Second temp file to use */
  i64 iWrite2 = 0;                /* Write offset for pTemp2 */
  int nIter;                      /* Number of iterators used */
  int nByte;                      /* Bytes of space required for aIter/aTree */
  int N = 2;                      /* Power of 2 >= nIter */

  assert( pSorter );

  /* If no data has been written to disk, then do not do so now. Instead,
  ** sort the VdbeSorter.pRecord list. The vdbe layer will read data directly
  ** from the in-memory list.  */
  if( pSorter->nPMA==0 ){

    *pbEof = !pSorter->pRecord;
    assert( pSorter->aTree==0 );
    return vdbeSorterSort(pCsr);
  }


  /* Write the current in-memory list to a PMA. */
  rc = vdbeSorterListToPMA(db, pCsr);
  if( rc!=SQLITE_OK ) return rc;

  /* Allocate space for aIter[] and aTree[]. */
  nIter = pSorter->nPMA;
  if( nIter>SORTER_MAX_MERGE_COUNT ) nIter = SORTER_MAX_MERGE_COUNT;
  assert( nIter>0 );
  while( N<nIter ) N += N;
  nByte = N * (sizeof(int) + sizeof(VdbeSorterIter));
  pSorter->aIter = (VdbeSorterIter *)sqlite3DbMallocZero(db, nByte);
  if( !pSorter->aIter ) return SQLITE_NOMEM;
  pSorter->aTree = (int *)&pSorter->aIter[N];
  pSorter->nTree = N;

  do {
    int iNew;                     /* Index of new, merged, PMA */

    for(iNew=0; 
        rc==SQLITE_OK && iNew*SORTER_MAX_MERGE_COUNT<pSorter->nPMA; 
        iNew++
    ){
      int rc2;                    /* Return code from fileWriterFinish() */
      FileWriter writer;          /* Object used to write to disk */
      i64 nWrite;                 /* Number of bytes in new PMA */

      memset(&writer, 0, sizeof(FileWriter));

      /* If there are SORTER_MAX_MERGE_COUNT or less PMAs in file pTemp1,
      ** initialize an iterator for each of them and break out of the loop.
      ** These iterators will be incrementally merged as the VDBE layer calls

      ** sqlite3VdbeSorterNext().
      **
      ** Otherwise, if pTemp1 contains more than SORTER_MAX_MERGE_COUNT PMAs,
      ** initialize interators for SORTER_MAX_MERGE_COUNT of them. These PMAs
      ** are merged into a single PMA that is written to file pTemp2.
      */
      rc = vdbeSorterInitMerge(db, pCsr, &nWrite);
      assert( rc!=SQLITE_OK || pSorter->aIter[ pSorter->aTree[1] ].pFile );
      if( rc!=SQLITE_OK || pSorter->nPMA<=SORTER_MAX_MERGE_COUNT ){
        break;
      }

      /* Open the second temp file, if it is not already open. */
      if( pTemp2==0 ){
        assert( iWrite2==0 );
        rc = vdbeSorterOpenTempFile(db, &pTemp2);
      }

      if( rc==SQLITE_OK ){
        int bEof = 0;
        fileWriterInit(db, pTemp2, &writer, iWrite2);
        fileWriterWriteVarint(&writer, nWrite);
        while( rc==SQLITE_OK && bEof==0 ){
          VdbeSorterIter *pIter = &pSorter->aIter[ pSorter->aTree[1] ];
          assert( pIter->pFile );

          fileWriterWriteVarint(&writer, pIter->nKey);
          fileWriterWrite(&writer, pIter->aKey, pIter->nKey);


          rc = sqlite3VdbeSorterNext(db, pCsr, &bEof);
        }
        rc2 = fileWriterFinish(db, &writer, &iWrite2);
        if( rc==SQLITE_OK ) rc = rc2;
      }
    }

    if( pSorter->nPMA<=SORTER_MAX_MERGE_COUNT ){
      break;
    }else{
      sqlite3_file *pTmp = pSorter->pTemp1;
      pSorter->nPMA = iNew;
      pSorter->pTemp1 = pTemp2;
      pTemp2 = pTmp;
      pSorter->iWriteOff = iWrite2;
      pSorter->iReadOff = 0;
      iWrite2 = 0;
    }
  }while( rc==SQLITE_OK );

  if( pTemp2 ){
    sqlite3OsCloseFree(pTemp2);
  }
  *pbEof = (pSorter->aIter[pSorter->aTree[1]].pFile==0);
  return rc;
}

/*
** Advance to the next element in the sorter.
*/
SQLITE_PRIVATE int sqlite3VdbeSorterNext(sqlite3 *db, const VdbeCursor *pCsr, int *pbEof){
  VdbeSorter *pSorter = pCsr->pSorter;
  int rc;                         /* Return code */


  if( pSorter->aTree ){
    int iPrev = pSorter->aTree[1];/* Index of iterator to advance */
    rc = vdbeSorterIterNext(db, &pSorter->aIter[iPrev]);
    if( rc==SQLITE_OK ){
      int i;                      /* Index of aTree[] to recalculate */
      VdbeSorterIter *pIter1;     /* First iterator to compare */
      VdbeSorterIter *pIter2;     /* Second iterator to compare */
      u8 *pKey2;                  /* To pIter2->aKey, or 0 if record cached */

      /* Find the first two iterators to compare. The one that was just
      ** advanced (iPrev) and the one next to it in the array.  */
      pIter1 = &pSorter->aIter[(iPrev & 0xFFFE)];
      pIter2 = &pSorter->aIter[(iPrev | 0x0001)];
      pKey2 = pIter2->aKey;

      for(i=(pSorter->nTree+iPrev)/2; i>0; i=i/2){
        /* Compare pIter1 and pIter2. Store the result in variable iRes. */
        int iRes;
        if( pIter1->pFile==0 ){
          iRes = +1;
        }else if( pIter2->pFile==0 ){
          iRes = -1;
        }else{
          vdbeSorterCompare(pCsr, 0, 
              pIter1->aKey, pIter1->nKey, pKey2, pIter2->nKey, &iRes
          );
        }

        /* If pIter1 contained the smaller value, set aTree[i] to its index.
        ** Then set pIter2 to the next iterator to compare to pIter1. In this
        ** case there is no cache of pIter2 in pSorter->pUnpacked, so set
        ** pKey2 to point to the record belonging to pIter2.
        **
        ** Alternatively, if pIter2 contains the smaller of the two values,
        ** set aTree[i] to its index and update pIter1. If vdbeSorterCompare()
        ** was actually called above, then pSorter->pUnpacked now contains
        ** a value equivalent to pIter2. So set pKey2 to NULL to prevent
        ** vdbeSorterCompare() from decoding pIter2 again.  */
        if( iRes<=0 ){
          pSorter->aTree[i] = (int)(pIter1 - pSorter->aIter);
          pIter2 = &pSorter->aIter[ pSorter->aTree[i ^ 0x0001] ];
          pKey2 = pIter2->aKey;
        }else{
          if( pIter1->pFile ) pKey2 = 0;
          pSorter->aTree[i] = (int)(pIter2 - pSorter->aIter);
          pIter1 = &pSorter->aIter[ pSorter->aTree[i ^ 0x0001] ];
        }

      }
      *pbEof = (pSorter->aIter[pSorter->aTree[1]].pFile==0);
    }
  }else{
    SorterRecord *pFree = pSorter->pRecord;
    pSorter->pRecord = pFree->pNext;
    pFree->pNext = 0;
    vdbeSorterRecordFree(db, pFree);
    *pbEof = !pSorter->pRecord;
    rc = SQLITE_OK;
  }
  return rc;
}

/*
** Return a pointer to a buffer owned by the sorter that contains the 
** current key.
*/
static void *vdbeSorterRowkey(
  const VdbeSorter *pSorter,      /* Sorter object */
  int *pnKey                      /* OUT: Size of current key in bytes */
){
  void *pKey;
  if( pSorter->aTree ){


    VdbeSorterIter *pIter;




    pIter = &pSorter->aIter[ pSorter->aTree[1] ];

    *pnKey = pIter->nKey;
    pKey = pIter->aKey;
  }else{
    *pnKey = pSorter->pRecord->nVal;
    pKey = pSorter->pRecord->pVal;
  }
  return pKey;
}

/*
** Copy the current sorter key into the memory cell pOut.
*/