FCL/sf/os/persistentdata: comparison persistentstorage/sql/SQLite364/vdbeaux.c

equal deleted inserted replaced

--1:000000000000
+:08ec8eefde2f
+/*
+** 2003 September 6
+**
+** 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 used for creating, destroying, and populating
+** a VDBE (or an "sqlite3_stmt" as it is known to the outside world.)  Prior
+** to version 2.8.7, all this code was combined into the vdbe.c source file.
+** But that file was getting too big so this subroutines were split out.
+**
+** $Id: vdbeaux.c,v 1.412 2008/10/11 17:51:39 danielk1977 Exp $
+*/
+#include "sqliteInt.h"
+#include <ctype.h>
+#include "vdbeInt.h"
+/*
+** When debugging the code generator in a symbolic debugger, one can
+** set the sqlite3VdbeAddopTrace to 1 and all opcodes will be printed
+** as they are added to the instruction stream.
+*/
+#ifdef SQLITE_DEBUG
+int sqlite3VdbeAddopTrace = 0;
+#endif
+/*
+** Create a new virtual database engine.
+*/
+Vdbe *sqlite3VdbeCreate(sqlite3 *db){
+Vdbe *p;
+p = sqlite3DbMallocZero(db, sizeof(Vdbe) );
+if( p==0 ) return 0;
+p->db = db;
+if( db->pVdbe ){
+db->pVdbe->pPrev = p;
+}
+p->pNext = db->pVdbe;
+p->pPrev = 0;
+db->pVdbe = p;
+p->magic = VDBE_MAGIC_INIT;
+return p;
+}
+/*
+** Remember the SQL string for a prepared statement.
+*/
+void sqlite3VdbeSetSql(Vdbe *p, const char *z, int n){
+if( p==0 ) return;
+assert( p->zSql==0 );
+p->zSql = sqlite3DbStrNDup(p->db, z, n);
+}
+/*
+** Return the SQL associated with a prepared statement
+*/
+const char *sqlite3_sql(sqlite3_stmt *pStmt){
+return ((Vdbe *)pStmt)->zSql;
+}
+/*
+** Swap all content between two VDBE structures.
+*/
+void sqlite3VdbeSwap(Vdbe *pA, Vdbe *pB){
+Vdbe tmp, *pTmp;
+char *zTmp;
+int nTmp;
+tmp = *pA;
+*pA = *pB;
+*pB = tmp;
+pTmp = pA->pNext;
+pA->pNext = pB->pNext;
+pB->pNext = pTmp;
+pTmp = pA->pPrev;
+pA->pPrev = pB->pPrev;
+pB->pPrev = pTmp;
+zTmp = pA->zSql;
+pA->zSql = pB->zSql;
+pB->zSql = zTmp;
+nTmp = pA->nSql;
+pA->nSql = pB->nSql;
+pB->nSql = nTmp;
+}
+#ifdef SQLITE_DEBUG
+/*
+** Turn tracing on or off
+*/
+void sqlite3VdbeTrace(Vdbe *p, FILE *trace){
+p->trace = trace;
+}
+#endif
+/*
+** Resize the Vdbe.aOp array so that it contains at least N
+** elements.
+**
+** If an out-of-memory error occurs while resizing the array,
+** Vdbe.aOp and Vdbe.nOpAlloc remain unchanged (this is so that
+** any opcodes already allocated can be correctly deallocated
+** along with the rest of the Vdbe).
+*/
+static void resizeOpArray(Vdbe *p, int N){
+VdbeOp *pNew;
+pNew = sqlite3DbRealloc(p->db, p->aOp, N*sizeof(Op));
+if( pNew ){
+p->nOpAlloc = N;
+p->aOp = pNew;
+}
+}
+/*
+** Add a new instruction to the list of instructions current in the
+** VDBE.  Return the address of the new instruction.
+**
+** Parameters:
+**
+**    p               Pointer to the VDBE
+**
+**    op              The opcode for this instruction
+**
+**    p1, p2, p3      Operands
+**
+** Use the sqlite3VdbeResolveLabel() function to fix an address and
+** the sqlite3VdbeChangeP4() function to change the value of the P4
+** operand.
+*/
+int sqlite3VdbeAddOp3(Vdbe *p, int op, int p1, int p2, int p3){
+int i;
+VdbeOp *pOp;
+i = p->nOp;
+assert( p->magic==VDBE_MAGIC_INIT );
+if( p->nOpAlloc<=i ){
+resizeOpArray(p, p->nOpAlloc ? p->nOpAlloc*2 : 1024/sizeof(Op));
+if( p->db->mallocFailed ){
+return 0;
+}
+}
+p->nOp++;
+pOp = &p->aOp[i];
+pOp->opcode = op;
+pOp->p5 = 0;
+pOp->p1 = p1;
+pOp->p2 = p2;
+pOp->p3 = p3;
+pOp->p4.p = 0;
+pOp->p4type = P4_NOTUSED;
+p->expired = 0;
+#ifdef SQLITE_DEBUG
+pOp->zComment = 0;
+if( sqlite3VdbeAddopTrace ) sqlite3VdbePrintOp(0, i, &p->aOp[i]);
+#endif
+#ifdef VDBE_PROFILE
+pOp->cycles = 0;
+pOp->cnt = 0;
+#endif
+return i;
+}
+int sqlite3VdbeAddOp0(Vdbe *p, int op){
+return sqlite3VdbeAddOp3(p, op, 0, 0, 0);
+}
+int sqlite3VdbeAddOp1(Vdbe *p, int op, int p1){
+return sqlite3VdbeAddOp3(p, op, p1, 0, 0);
+}
+int sqlite3VdbeAddOp2(Vdbe *p, int op, int p1, int p2){
+return sqlite3VdbeAddOp3(p, op, p1, p2, 0);
+}
+/*
+** Add an opcode that includes the p4 value as a pointer.
+*/
+int sqlite3VdbeAddOp4(
+Vdbe *p,            /* Add the opcode to this VM */
+int op,             /* The new opcode */
+int p1,             /* The P1 operand */
+int p2,             /* The P2 operand */
+int p3,             /* The P3 operand */
+const char *zP4,    /* The P4 operand */
+int p4type          /* P4 operand type */
+){
+int addr = sqlite3VdbeAddOp3(p, op, p1, p2, p3);
+sqlite3VdbeChangeP4(p, addr, zP4, p4type);
+return addr;
+}
+/*
+** Create a new symbolic label for an instruction that has yet to be
+** coded.  The symbolic label is really just a negative number.  The
+** label can be used as the P2 value of an operation.  Later, when
+** the label is resolved to a specific address, the VDBE will scan
+** through its operation list and change all values of P2 which match
+** the label into the resolved address.
+**
+** The VDBE knows that a P2 value is a label because labels are
+** always negative and P2 values are suppose to be non-negative.
+** Hence, a negative P2 value is a label that has yet to be resolved.
+**
+** Zero is returned if a malloc() fails.
+*/
+int sqlite3VdbeMakeLabel(Vdbe *p){
+int i;
+i = p->nLabel++;
+assert( p->magic==VDBE_MAGIC_INIT );
+if( i>=p->nLabelAlloc ){
+p->nLabelAlloc = p->nLabelAlloc*2 + 10;
+p->aLabel = sqlite3DbReallocOrFree(p->db, p->aLabel,
+p->nLabelAlloc*sizeof(p->aLabel[0]));
+}
+if( p->aLabel ){
+p->aLabel[i] = -1;
+}
+return -1-i;
+}
+/*
+** Resolve label "x" to be the address of the next instruction to
+** be inserted.  The parameter "x" must have been obtained from
+** a prior call to sqlite3VdbeMakeLabel().
+*/
+void sqlite3VdbeResolveLabel(Vdbe *p, int x){
+int j = -1-x;
+assert( p->magic==VDBE_MAGIC_INIT );
+assert( j>=0 && j<p->nLabel );
+if( p->aLabel ){
+p->aLabel[j] = p->nOp;
+}
+}
+/*
+** Loop through the program looking for P2 values that are negative
+** on jump instructions.  Each such value is a label.  Resolve the
+** label by setting the P2 value to its correct non-zero value.
+**
+** This routine is called once after all opcodes have been inserted.
+**
+** Variable *pMaxFuncArgs is set to the maximum value of any P2 argument
+** to an OP_Function, OP_AggStep or OP_VFilter opcode. This is used by
+** sqlite3VdbeMakeReady() to size the Vdbe.apArg[] array.
+**
+** This routine also does the following optimization:  It scans for
+** instructions that might cause a statement rollback.  Such instructions
+** are:
+**
+**   *  OP_Halt with P1=SQLITE_CONSTRAINT and P2=OE_Abort.
+**   *  OP_Destroy
+**   *  OP_VUpdate
+**   *  OP_VRename
+**
+** If no such instruction is found, then every Statement instruction
+** is changed to a Noop.  In this way, we avoid creating the statement
+** journal file unnecessarily.
+*/
+static void resolveP2Values(Vdbe *p, int *pMaxFuncArgs){
+int i;
+int nMaxArgs = 0;
+Op *pOp;
+int *aLabel = p->aLabel;
+int doesStatementRollback = 0;
+int hasStatementBegin = 0;
+for(pOp=p->aOp, i=p->nOp-1; i>=0; i--, pOp++){
+u8 opcode = pOp->opcode;
+if( opcode==OP_Function || opcode==OP_AggStep ){
+if( pOp->p5>nMaxArgs ) nMaxArgs = pOp->p5;
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+}else if( opcode==OP_VUpdate ){
+if( pOp->p2>nMaxArgs ) nMaxArgs = pOp->p2;
+#endif
+}
+if( opcode==OP_Halt ){
+if( pOp->p1==SQLITE_CONSTRAINT && pOp->p2==OE_Abort ){
+doesStatementRollback = 1;
+}
+}else if( opcode==OP_Statement ){
+hasStatementBegin = 1;
+}else if( opcode==OP_Destroy ){
+doesStatementRollback = 1;
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+}else if( opcode==OP_VUpdate || opcode==OP_VRename ){
+doesStatementRollback = 1;
+}else if( opcode==OP_VFilter ){
+int n;
+assert( p->nOp - i >= 3 );
+assert( pOp[-1].opcode==OP_Integer );
+n = pOp[-1].p1;
+if( n>nMaxArgs ) nMaxArgs = n;
+#endif
+}
+if( sqlite3VdbeOpcodeHasProperty(opcode, OPFLG_JUMP) && pOp->p2<0 ){
+assert( -1-pOp->p2<p->nLabel );
+pOp->p2 = aLabel[-1-pOp->p2];
+}
+}
+sqlite3DbFree(p->db, p->aLabel);
+p->aLabel = 0;
+*pMaxFuncArgs = nMaxArgs;
+/* If we never rollback a statement transaction, then statement
+** transactions are not needed.  So change every OP_Statement
+** opcode into an OP_Noop.  This avoid a call to sqlite3OsOpenExclusive()
+** which can be expensive on some platforms.
+*/
+if( hasStatementBegin && !doesStatementRollback ){
+for(pOp=p->aOp, i=p->nOp-1; i>=0; i--, pOp++){
+if( pOp->opcode==OP_Statement ){
+pOp->opcode = OP_Noop;
+}
+}
+}
+}
+/*
+** Return the address of the next instruction to be inserted.
+*/
+int sqlite3VdbeCurrentAddr(Vdbe *p){
+assert( p->magic==VDBE_MAGIC_INIT );
+return p->nOp;
+}
+/*
+** Add a whole list of operations to the operation stack.  Return the
+** address of the first operation added.
+*/
+int sqlite3VdbeAddOpList(Vdbe *p, int nOp, VdbeOpList const *aOp){
+int addr;
+assert( p->magic==VDBE_MAGIC_INIT );
+if( p->nOp + nOp > p->nOpAlloc ){
+resizeOpArray(p, p->nOpAlloc ? p->nOpAlloc*2 : 1024/sizeof(Op));
+assert( p->nOp+nOp<=p->nOpAlloc || p->db->mallocFailed );
+}
+if( p->db->mallocFailed ){
+return 0;
+}
+addr = p->nOp;
+if( nOp>0 ){
+int i;
+VdbeOpList const *pIn = aOp;
+for(i=0; i<nOp; i++, pIn++){
+int p2 = pIn->p2;
+VdbeOp *pOut = &p->aOp[i+addr];
+pOut->opcode = pIn->opcode;
+pOut->p1 = pIn->p1;
+if( p2<0 && sqlite3VdbeOpcodeHasProperty(pOut->opcode, OPFLG_JUMP) ){
+pOut->p2 = addr + ADDR(p2);
+}else{
+pOut->p2 = p2;
+}
+pOut->p3 = pIn->p3;
+pOut->p4type = P4_NOTUSED;
+pOut->p4.p = 0;
+pOut->p5 = 0;
+#ifdef SQLITE_DEBUG
+pOut->zComment = 0;
+if( sqlite3VdbeAddopTrace ){
+sqlite3VdbePrintOp(0, i+addr, &p->aOp[i+addr]);
+}
+#endif
+}
+p->nOp += nOp;
+}
+return addr;
+}
+/*
+** Change the value of the P1 operand for a specific instruction.
+** This routine is useful when a large program is loaded from a
+** static array using sqlite3VdbeAddOpList but we want to make a
+** few minor changes to the program.
+*/
+void sqlite3VdbeChangeP1(Vdbe *p, int addr, int val){
+assert( p==0 || p->magic==VDBE_MAGIC_INIT );
+if( p && addr>=0 && p->nOp>addr && p->aOp ){
+p->aOp[addr].p1 = val;
+}
+}
+/*
+** Change the value of the P2 operand for a specific instruction.
+** This routine is useful for setting a jump destination.
+*/
+void sqlite3VdbeChangeP2(Vdbe *p, int addr, int val){
+assert( p==0 || p->magic==VDBE_MAGIC_INIT );
+if( p && addr>=0 && p->nOp>addr && p->aOp ){
+p->aOp[addr].p2 = val;
+}
+}
+/*
+** Change the value of the P3 operand for a specific instruction.
+*/
+void sqlite3VdbeChangeP3(Vdbe *p, int addr, int val){
+assert( p==0 || p->magic==VDBE_MAGIC_INIT );
+if( p && addr>=0 && p->nOp>addr && p->aOp ){
+p->aOp[addr].p3 = val;
+}
+}
+/*
+** Change the value of the P5 operand for the most recently
+** added operation.
+*/
+void sqlite3VdbeChangeP5(Vdbe *p, u8 val){
+assert( p==0 || p->magic==VDBE_MAGIC_INIT );
+if( p && p->aOp ){
+assert( p->nOp>0 );
+p->aOp[p->nOp-1].p5 = val;
+}
+}
+/*
+** Change the P2 operand of instruction addr so that it points to
+** the address of the next instruction to be coded.
+*/
+void sqlite3VdbeJumpHere(Vdbe *p, int addr){
+sqlite3VdbeChangeP2(p, addr, p->nOp);
+}
+/*
+** If the input FuncDef structure is ephemeral, then free it.  If
+** the FuncDef is not ephermal, then do nothing.
+*/
+static void freeEphemeralFunction(sqlite3 *db, FuncDef *pDef){
+if( pDef && (pDef->flags & SQLITE_FUNC_EPHEM)!=0 ){
+sqlite3DbFree(db, pDef);
+}
+}
+/*
+** Delete a P4 value if necessary.
+*/
+static void freeP4(sqlite3 *db, int p4type, void *p4){
+if( p4 ){
+switch( p4type ){
+case P4_REAL:
+case P4_INT64:
+case P4_MPRINTF:
+case P4_DYNAMIC:
+case P4_KEYINFO:
+case P4_INTARRAY:
+case P4_KEYINFO_HANDOFF: {
+sqlite3DbFree(db, p4);
+break;
+}
+case P4_VDBEFUNC: {
+VdbeFunc *pVdbeFunc = (VdbeFunc *)p4;
+freeEphemeralFunction(db, pVdbeFunc->pFunc);
+sqlite3VdbeDeleteAuxData(pVdbeFunc, 0);
+sqlite3DbFree(db, pVdbeFunc);
+break;
+}
+case P4_FUNCDEF: {
+freeEphemeralFunction(db, (FuncDef*)p4);
+break;
+}
+case P4_MEM: {
+sqlite3ValueFree((sqlite3_value*)p4);
+break;
+}
+}
+}
+}
+/*
+** Change N opcodes starting at addr to No-ops.
+*/
+void sqlite3VdbeChangeToNoop(Vdbe *p, int addr, int N){
+if( p && p->aOp ){
+VdbeOp *pOp = &p->aOp[addr];
+sqlite3 *db = p->db;
+while( N-- ){
+freeP4(db, pOp->p4type, pOp->p4.p);
+memset(pOp, 0, sizeof(pOp[0]));
+pOp->opcode = OP_Noop;
+pOp++;
+}
+}
+}
+/*
+** Change the value of the P4 operand for a specific instruction.
+** This routine is useful when a large program is loaded from a
+** static array using sqlite3VdbeAddOpList but we want to make a
+** few minor changes to the program.
+**
+** If n>=0 then the P4 operand is dynamic, meaning that a copy of
+** the string is made into memory obtained from sqlite3_malloc().
+** A value of n==0 means copy bytes of zP4 up to and including the
+** first null byte.  If n>0 then copy n+1 bytes of zP4.
+**
+** If n==P4_KEYINFO it means that zP4 is a pointer to a KeyInfo structure.
+** A copy is made of the KeyInfo structure into memory obtained from
+** sqlite3_malloc, to be freed when the Vdbe is finalized.
+** n==P4_KEYINFO_HANDOFF indicates that zP4 points to a KeyInfo structure
+** stored in memory that the caller has obtained from sqlite3_malloc. The
+** caller should not free the allocation, it will be freed when the Vdbe is
+** finalized.
+**
+** Other values of n (P4_STATIC, P4_COLLSEQ etc.) indicate that zP4 points
+** to a string or structure that is guaranteed to exist for the lifetime of
+** the Vdbe. In these cases we can just copy the pointer.
+**
+** If addr<0 then change P4 on the most recently inserted instruction.
+*/
+void sqlite3VdbeChangeP4(Vdbe *p, int addr, const char *zP4, int n){
+Op *pOp;
+sqlite3 *db;
+assert( p!=0 );
+db = p->db;
+assert( p->magic==VDBE_MAGIC_INIT );
+if( p->aOp==0 || db->mallocFailed ){
+if (n != P4_KEYINFO) {
+freeP4(db, n, (void*)*(char**)&zP4);
+}
+return;
+}
+assert( addr<p->nOp );
+if( addr<0 ){
+addr = p->nOp - 1;
+if( addr<0 ) return;
+}
+pOp = &p->aOp[addr];
+freeP4(db, pOp->p4type, pOp->p4.p);
+pOp->p4.p = 0;
+if( n==P4_INT32 ){
+/* Note: this cast is safe, because the origin data point was an int
+** that was cast to a (const char *). */
+pOp->p4.i = SQLITE_PTR_TO_INT(zP4);
+pOp->p4type = n;
+}else if( zP4==0 ){
+pOp->p4.p = 0;
+pOp->p4type = P4_NOTUSED;
+}else if( n==P4_KEYINFO ){
+KeyInfo *pKeyInfo;
+int nField, nByte;
+nField = ((KeyInfo*)zP4)->nField;
+nByte = sizeof(*pKeyInfo) + (nField-1)*sizeof(pKeyInfo->aColl[0]) + nField;
+pKeyInfo = sqlite3Malloc( nByte );
+pOp->p4.pKeyInfo = pKeyInfo;
+if( pKeyInfo ){
+u8 *aSortOrder;
+memcpy(pKeyInfo, zP4, nByte);
+aSortOrder = pKeyInfo->aSortOrder;
+if( aSortOrder ){
+pKeyInfo->aSortOrder = (unsigned char*)&pKeyInfo->aColl[nField];
+memcpy(pKeyInfo->aSortOrder, aSortOrder, nField);
+}
+pOp->p4type = P4_KEYINFO;
+}else{
+p->db->mallocFailed = 1;
+pOp->p4type = P4_NOTUSED;
+}
+}else if( n==P4_KEYINFO_HANDOFF ){
+pOp->p4.p = (void*)zP4;
+pOp->p4type = P4_KEYINFO;
+}else if( n<0 ){
+pOp->p4.p = (void*)zP4;
+pOp->p4type = n;
+}else{
+if( n==0 ) n = strlen(zP4);
+pOp->p4.z = sqlite3DbStrNDup(p->db, zP4, n);
+pOp->p4type = P4_DYNAMIC;
+}
+}
+#ifndef NDEBUG
+/*
+** Change the comment on the the most recently coded instruction.  Or
+** insert a No-op and add the comment to that new instruction.  This
+** makes the code easier to read during debugging.  None of this happens
+** in a production build.
+*/
+void sqlite3VdbeComment(Vdbe *p, const char *zFormat, ...){
+va_list ap;
+assert( p->nOp>0 || p->aOp==0 );
+assert( p->aOp==0 || p->aOp[p->nOp-1].zComment==0 || p->db->mallocFailed );
+if( p->nOp ){
+char **pz = &p->aOp[p->nOp-1].zComment;
+va_start(ap, zFormat);
+sqlite3DbFree(p->db, *pz);
+*pz = sqlite3VMPrintf(p->db, zFormat, ap);
+va_end(ap);
+}
+}
+void sqlite3VdbeNoopComment(Vdbe *p, const char *zFormat, ...){
+va_list ap;
+sqlite3VdbeAddOp0(p, OP_Noop);
+assert( p->nOp>0 || p->aOp==0 );
+assert( p->aOp==0 || p->aOp[p->nOp-1].zComment==0 || p->db->mallocFailed );
+if( p->nOp ){
+char **pz = &p->aOp[p->nOp-1].zComment;
+va_start(ap, zFormat);
+sqlite3DbFree(p->db, *pz);
+*pz = sqlite3VMPrintf(p->db, zFormat, ap);
+va_end(ap);
+}
+}
+#endif  /* NDEBUG */
+/*
+** Return the opcode for a given address.
+*/
+VdbeOp *sqlite3VdbeGetOp(Vdbe *p, int addr){
+assert( p->magic==VDBE_MAGIC_INIT );
+assert( (addr>=0 && addr<p->nOp) || p->db->mallocFailed );
+return ((addr>=0 && addr<p->nOp)?(&p->aOp[addr]):0);
+}
+#if !defined(SQLITE_OMIT_EXPLAIN) || !defined(NDEBUG) \
+|| defined(VDBE_PROFILE) || defined(SQLITE_DEBUG)
+/*
+** Compute a string that describes the P4 parameter for an opcode.
+** Use zTemp for any required temporary buffer space.
+*/
+static char *displayP4(Op *pOp, char *zTemp, int nTemp){
+char *zP4 = zTemp;
+assert( nTemp>=20 );
+switch( pOp->p4type ){
+case P4_KEYINFO_STATIC:
+case P4_KEYINFO: {
+int i, j;
+KeyInfo *pKeyInfo = pOp->p4.pKeyInfo;
+sqlite3_snprintf(nTemp, zTemp, "keyinfo(%d", pKeyInfo->nField);
+i = strlen(zTemp);
+for(j=0; j<pKeyInfo->nField; j++){
+CollSeq *pColl = pKeyInfo->aColl[j];
+if( pColl ){
+int n = strlen(pColl->zName);
+if( i+n>nTemp-6 ){
+memcpy(&zTemp[i],",...",4);
+break;
+}
+zTemp[i++] = ',';
+if( pKeyInfo->aSortOrder && pKeyInfo->aSortOrder[j] ){
+zTemp[i++] = '-';
+}
+memcpy(&zTemp[i], pColl->zName,n+1);
+i += n;
+}else if( i+4<nTemp-6 ){
+memcpy(&zTemp[i],",nil",4);
+i += 4;
+}
+}
+zTemp[i++] = ')';
+zTemp[i] = 0;
+assert( i<nTemp );
+break;
+}
+case P4_COLLSEQ: {
+CollSeq *pColl = pOp->p4.pColl;
+sqlite3_snprintf(nTemp, zTemp, "collseq(%.20s)", pColl->zName);
+break;
+}
+case P4_FUNCDEF: {
+FuncDef *pDef = pOp->p4.pFunc;
+sqlite3_snprintf(nTemp, zTemp, "%s(%d)", pDef->zName, pDef->nArg);
+break;
+}
+case P4_INT64: {
+sqlite3_snprintf(nTemp, zTemp, "%lld", *pOp->p4.pI64);
+break;
+}
+case P4_INT32: {
+sqlite3_snprintf(nTemp, zTemp, "%d", pOp->p4.i);
+break;
+}
+case P4_REAL: {
+sqlite3_snprintf(nTemp, zTemp, "%.16g", *pOp->p4.pReal);
+break;
+}
+case P4_MEM: {
+Mem *pMem = pOp->p4.pMem;
+assert( (pMem->flags & MEM_Null)==0 );
+if( pMem->flags & MEM_Str ){
+zP4 = pMem->z;
+}else if( pMem->flags & MEM_Int ){
+sqlite3_snprintf(nTemp, zTemp, "%lld", pMem->u.i);
+}else if( pMem->flags & MEM_Real ){
+sqlite3_snprintf(nTemp, zTemp, "%.16g", pMem->r);
+}
+break;
+}
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+case P4_VTAB: {
+sqlite3_vtab *pVtab = pOp->p4.pVtab;
+sqlite3_snprintf(nTemp, zTemp, "vtab:%p:%p", pVtab, pVtab->pModule);
+break;
+}
+#endif
+case P4_INTARRAY: {
+sqlite3_snprintf(nTemp, zTemp, "intarray");
+break;
+}
+default: {
+zP4 = pOp->p4.z;
+if( zP4==0 ){
+zP4 = zTemp;
+zTemp[0] = 0;
+}
+}
+}
+assert( zP4!=0 );
+return zP4;
+}
+#endif
+/*
+** Declare to the Vdbe that the BTree object at db->aDb[i] is used.
+**
+*/
+void sqlite3VdbeUsesBtree(Vdbe *p, int i){
+int mask;
+assert( i>=0 && i<p->db->nDb );
+assert( i<sizeof(p->btreeMask)*8 );
+mask = 1<<i;
+if( (p->btreeMask & mask)==0 ){
+p->btreeMask |= mask;
+sqlite3BtreeMutexArrayInsert(&p->aMutex, p->db->aDb[i].pBt);
+}
+}
+#if defined(VDBE_PROFILE) || defined(SQLITE_DEBUG)
+/*
+** Print a single opcode.  This routine is used for debugging only.
+*/
+void sqlite3VdbePrintOp(FILE *pOut, int pc, Op *pOp){
+char *zP4;
+char zPtr[50];
+static const char *zFormat1 = "%4d %-13s %4d %4d %4d %-4s %.2X %s\n";
+if( pOut==0 ) pOut = stdout;
+zP4 = displayP4(pOp, zPtr, sizeof(zPtr));
+fprintf(pOut, zFormat1, pc,
+sqlite3OpcodeName(pOp->opcode), pOp->p1, pOp->p2, pOp->p3, zP4, pOp->p5,
+#ifdef SQLITE_DEBUG
+pOp->zComment ? pOp->zComment : ""
+#else
+""
+#endif
+);
+fflush(pOut);
+}
+#endif
+/*
+** Release an array of N Mem elements
+*/
+static void releaseMemArray(Mem *p, int N){
+if( p && N ){
+Mem *pEnd;
+sqlite3 *db = p->db;
+int malloc_failed = db->mallocFailed;
+for(pEnd=&p[N]; p<pEnd; p++){
+assert( (&p[1])==pEnd || p[0].db==p[1].db );
+/* This block is really an inlined version of sqlite3VdbeMemRelease()
+** that takes advantage of the fact that the memory cell value is
+** being set to NULL after releasing any dynamic resources.
+**
+** The justification for duplicating code is that according to
+** callgrind, this causes a certain test case to hit the CPU 4.7
+** percent less (x86 linux, gcc version 4.1.2, -O6) than if
+** sqlite3MemRelease() were called from here. With -O2, this jumps
+** to 6.6 percent. The test case is inserting 1000 rows into a table
+** with no indexes using a single prepared INSERT statement, bind()
+** and reset(). Inserts are grouped into a transaction.
+*/
+if( p->flags&(MEM_Agg|MEM_Dyn) ){
+sqlite3VdbeMemRelease(p);
+}else if( p->zMalloc ){
+sqlite3DbFree(db, p->zMalloc);
+p->zMalloc = 0;
+}
+p->flags = MEM_Null;
+}
+db->mallocFailed = malloc_failed;
+}
+}
+#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
+int sqlite3VdbeReleaseBuffers(Vdbe *p){
+int ii;
+int nFree = 0;
+assert( sqlite3_mutex_held(p->db->mutex) );
+for(ii=1; ii<=p->nMem; ii++){
+Mem *pMem = &p->aMem[ii];
+if( pMem->z && pMem->flags&MEM_Dyn ){
+assert( !pMem->xDel );
+nFree += sqlite3DbMallocSize(pMem->db, pMem->z);
+sqlite3VdbeMemRelease(pMem);
+}
+}
+return nFree;
+}
+#endif
+#ifndef SQLITE_OMIT_EXPLAIN
+/*
+** Give a listing of the program in the virtual machine.
+**
+** The interface is the same as sqlite3VdbeExec().  But instead of
+** running the code, it invokes the callback once for each instruction.
+** This feature is used to implement "EXPLAIN".
+**
+** When p->explain==1, each instruction is listed.  When
+** p->explain==2, only OP_Explain instructions are listed and these
+** are shown in a different format.  p->explain==2 is used to implement
+** EXPLAIN QUERY PLAN.
+*/
+int sqlite3VdbeList(
+Vdbe *p                   /* The VDBE */
+){
+sqlite3 *db = p->db;
+int i;
+int rc = SQLITE_OK;
+Mem *pMem = p->pResultSet = &p->aMem[1];
+assert( p->explain );
+if( p->magic!=VDBE_MAGIC_RUN ) return SQLITE_MISUSE;
+assert( db->magic==SQLITE_MAGIC_BUSY );
+assert( p->rc==SQLITE_OK || p->rc==SQLITE_BUSY );
+/* Even though this opcode does not use dynamic strings for
+** the result, result columns may become dynamic if the user calls
+** sqlite3_column_text16(), causing a translation to UTF-16 encoding.
+*/
+releaseMemArray(pMem, p->nMem);
+do{
+i = p->pc++;
+}while( i<p->nOp && p->explain==2 && p->aOp[i].opcode!=OP_Explain );
+if( i>=p->nOp ){
+p->rc = SQLITE_OK;
+rc = SQLITE_DONE;
+}else if( db->u1.isInterrupted ){
+p->rc = SQLITE_INTERRUPT;
+rc = SQLITE_ERROR;
+sqlite3SetString(&p->zErrMsg, db, "%s", sqlite3ErrStr(p->rc));
+}else{
+char *z;
+Op *pOp = &p->aOp[i];
+if( p->explain==1 ){
+pMem->flags = MEM_Int;
+pMem->type = SQLITE_INTEGER;
+pMem->u.i = i;                                /* Program counter */
+pMem++;
+pMem->flags = MEM_Static|MEM_Str|MEM_Term;
+pMem->z = (char*)sqlite3OpcodeName(pOp->opcode);  /* Opcode */
+assert( pMem->z!=0 );
+pMem->n = strlen(pMem->z);
+pMem->type = SQLITE_TEXT;
+pMem->enc = SQLITE_UTF8;
+pMem++;
+}
+pMem->flags = MEM_Int;
+pMem->u.i = pOp->p1;                          /* P1 */
+pMem->type = SQLITE_INTEGER;
+pMem++;
+pMem->flags = MEM_Int;
+pMem->u.i = pOp->p2;                          /* P2 */
+pMem->type = SQLITE_INTEGER;
+pMem++;
+if( p->explain==1 ){
+pMem->flags = MEM_Int;
+pMem->u.i = pOp->p3;                          /* P3 */
+pMem->type = SQLITE_INTEGER;
+pMem++;
+}
+if( sqlite3VdbeMemGrow(pMem, 32, 0) ){            /* P4 */
+p->db->mallocFailed = 1;
+return SQLITE_NOMEM;
+}
+pMem->flags = MEM_Dyn|MEM_Str|MEM_Term;
+z = displayP4(pOp, pMem->z, 32);
+if( z!=pMem->z ){
+sqlite3VdbeMemSetStr(pMem, z, -1, SQLITE_UTF8, 0);
+}else{
+assert( pMem->z!=0 );
+pMem->n = strlen(pMem->z);
+pMem->enc = SQLITE_UTF8;
+}
+pMem->type = SQLITE_TEXT;
+pMem++;
+if( p->explain==1 ){
+if( sqlite3VdbeMemGrow(pMem, 4, 0) ){
+p->db->mallocFailed = 1;
+return SQLITE_NOMEM;
+}
+pMem->flags = MEM_Dyn|MEM_Str|MEM_Term;
+pMem->n = 2;
+sqlite3_snprintf(3, pMem->z, "%.2x", pOp->p5);   /* P5 */
+pMem->type = SQLITE_TEXT;
+pMem->enc = SQLITE_UTF8;
+pMem++;
+#ifdef SQLITE_DEBUG
+if( pOp->zComment ){
+pMem->flags = MEM_Str|MEM_Term;
+pMem->z = pOp->zComment;
+pMem->n = strlen(pMem->z);
+pMem->enc = SQLITE_UTF8;
+pMem->type = SQLITE_TEXT;
+}else
+#endif
+{
+pMem->flags = MEM_Null;                       /* Comment */
+pMem->type = SQLITE_NULL;
+}
+}
+p->nResColumn = 8 - 5*(p->explain-1);
+p->rc = SQLITE_OK;
+rc = SQLITE_ROW;
+}
+return rc;
+}
+#endif /* SQLITE_OMIT_EXPLAIN */
+#ifdef SQLITE_DEBUG
+/*
+** Print the SQL that was used to generate a VDBE program.
+*/
+void sqlite3VdbePrintSql(Vdbe *p){
+int nOp = p->nOp;
+VdbeOp *pOp;
+if( nOp<1 ) return;
+pOp = &p->aOp[0];
+if( pOp->opcode==OP_Trace && pOp->p4.z!=0 ){
+const char *z = pOp->p4.z;
+while( isspace(*(u8*)z) ) z++;
+printf("SQL: [%s]\n", z);
+}
+}
+#endif
+#if !defined(SQLITE_OMIT_TRACE) && defined(SQLITE_ENABLE_IOTRACE)
+/*
+** Print an IOTRACE message showing SQL content.
+*/
+void sqlite3VdbeIOTraceSql(Vdbe *p){
+int nOp = p->nOp;
+VdbeOp *pOp;
+if( sqlite3IoTrace==0 ) return;
+if( nOp<1 ) return;
+pOp = &p->aOp[0];
+if( pOp->opcode==OP_Trace && pOp->p4.z!=0 ){
+int i, j;
+char z[1000];
+sqlite3_snprintf(sizeof(z), z, "%s", pOp->p4.z);
+for(i=0; isspace((unsigned char)z[i]); i++){}
+for(j=0; z[i]; i++){
+if( isspace((unsigned char)z[i]) ){
+if( z[i-1]!=' ' ){
+z[j++] = ' ';
+}
+}else{
+z[j++] = z[i];
+}
+}
+z[j] = 0;
+sqlite3IoTrace("SQL %s\n", z);
+}
+}
+#endif /* !SQLITE_OMIT_TRACE && SQLITE_ENABLE_IOTRACE */
+/*
+** Prepare a virtual machine for execution.  This involves things such
+** as allocating stack space and initializing the program counter.
+** After the VDBE has be prepped, it can be executed by one or more
+** calls to sqlite3VdbeExec().
+**
+** This is the only way to move a VDBE from VDBE_MAGIC_INIT to
+** VDBE_MAGIC_RUN.
+*/
+void sqlite3VdbeMakeReady(
+Vdbe *p,                       /* The VDBE */
+int nVar,                      /* Number of '?' see in the SQL statement */
+int nMem,                      /* Number of memory cells to allocate */
+int nCursor,                   /* Number of cursors to allocate */
+int isExplain                  /* True if the EXPLAIN keywords is present */
+){
+int n;
+sqlite3 *db = p->db;
+assert( p!=0 );
+assert( p->magic==VDBE_MAGIC_INIT );
+/* There should be at least one opcode.
+*/
+assert( p->nOp>0 );
+/* Set the magic to VDBE_MAGIC_RUN sooner rather than later. This
+* is because the call to resizeOpArray() below may shrink the
+* p->aOp[] array to save memory if called when in VDBE_MAGIC_RUN
+* state.
+*/
+p->magic = VDBE_MAGIC_RUN;
+/* For each cursor required, also allocate a memory cell. Memory
+** cells (nMem+1-nCursor)..nMem, inclusive, will never be used by
+** the vdbe program. Instead they are used to allocate space for
+** Cursor/BtCursor structures. The blob of memory associated with
+** cursor 0 is stored in memory cell nMem. Memory cell (nMem-1)
+** stores the blob of memory associated with cursor 1, etc.
+**
+** See also: allocateCursor().
+*/
+nMem += nCursor;
+/*
+** Allocation space for registers.
+*/
+if( p->aMem==0 ){
+int nArg;       /* Maximum number of args passed to a user function. */
+resolveP2Values(p, &nArg);
+/*resizeOpArray(p, p->nOp);*/
+assert( nVar>=0 );
+if( isExplain && nMem<10 ){
+p->nMem = nMem = 10;
+}
+p->aMem = sqlite3DbMallocZero(db,
+nMem*sizeof(Mem)               /* aMem */
++ nVar*sizeof(Mem)               /* aVar */
++ nArg*sizeof(Mem*)              /* apArg */
++ nVar*sizeof(char*)             /* azVar */
++ nCursor*sizeof(Cursor*) + 1    /* apCsr */
+);
+if( !db->mallocFailed ){
+p->aMem--;             /* aMem[] goes from 1..nMem */
+p->nMem = nMem;        /*       not from 0..nMem-1 */
+p->aVar = &p->aMem[nMem+1];
+p->nVar = nVar;
+p->okVar = 0;
+p->apArg = (Mem**)&p->aVar[nVar];
+p->azVar = (char**)&p->apArg[nArg];
+p->apCsr = (Cursor**)&p->azVar[nVar];
+p->nCursor = nCursor;
+for(n=0; n<nVar; n++){
+p->aVar[n].flags = MEM_Null;
+p->aVar[n].db = db;
+}
+for(n=1; n<=nMem; n++){
+p->aMem[n].flags = MEM_Null;
+p->aMem[n].db = db;
+}
+}
+}
+#ifdef SQLITE_DEBUG
+for(n=1; n<p->nMem; n++){
+assert( p->aMem[n].db==db );
+}
+#endif
+p->pc = -1;
+p->rc = SQLITE_OK;
+p->uniqueCnt = 0;
+p->errorAction = OE_Abort;
+p->explain |= isExplain;
+p->magic = VDBE_MAGIC_RUN;
+p->nChange = 0;
+p->cacheCtr = 1;
+p->minWriteFileFormat = 255;
+p->openedStatement = 0;
+#ifdef VDBE_PROFILE
+{
+int i;
+for(i=0; i<p->nOp; i++){
+p->aOp[i].cnt = 0;
+p->aOp[i].cycles = 0;
+}
+}
+#endif
+}
+/*
+** Close a VDBE cursor and release all the resources that cursor
+** happens to hold.
+*/
+void sqlite3VdbeFreeCursor(Vdbe *p, Cursor *pCx){
+if( pCx==0 ){
+return;
+}
+if( pCx->pBt ){
+sqlite3BtreeClose(pCx->pBt);
+/* The pCx->pCursor will be close automatically, if it exists, by
+** the call above. */
+}else if( pCx->pCursor ){
+sqlite3BtreeCloseCursor(pCx->pCursor);
+}
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+if( pCx->pVtabCursor ){
+sqlite3_vtab_cursor *pVtabCursor = pCx->pVtabCursor;
+const sqlite3_module *pModule = pCx->pModule;
+p->inVtabMethod = 1;
+(void)sqlite3SafetyOff(p->db);
+pModule->xClose(pVtabCursor);
+(void)sqlite3SafetyOn(p->db);
+p->inVtabMethod = 0;
+}
+#endif
+if( !pCx->ephemPseudoTable ){
+sqlite3DbFree(p->db, pCx->pData);
+}
+}
+/*
+** Close all cursors except for VTab cursors that are currently
+** in use.
+*/
+static void closeAllCursorsExceptActiveVtabs(Vdbe *p){
+int i;
+if( p->apCsr==0 ) return;
+for(i=0; i<p->nCursor; i++){
+Cursor *pC = p->apCsr[i];
+if( pC && (!p->inVtabMethod || !pC->pVtabCursor) ){
+sqlite3VdbeFreeCursor(p, pC);
+p->apCsr[i] = 0;
+}
+}
+}
+/*
+** Clean up the VM after execution.
+**
+** This routine will automatically close any cursors, lists, and/or
+** sorters that were left open.  It also deletes the values of
+** variables in the aVar[] array.
+*/
+static void Cleanup(Vdbe *p){
+int i;
+sqlite3 *db = p->db;
+closeAllCursorsExceptActiveVtabs(p);
+for(i=1; i<=p->nMem; i++){
+MemSetTypeFlag(&p->aMem[i], MEM_Null);
+}
+releaseMemArray(&p->aMem[1], p->nMem);
+sqlite3VdbeFifoClear(&p->sFifo);
+if( p->contextStack ){
+for(i=0; i<p->contextStackTop; i++){
+sqlite3VdbeFifoClear(&p->contextStack[i].sFifo);
+}
+sqlite3DbFree(db, p->contextStack);
+}
+p->contextStack = 0;
+p->contextStackDepth = 0;
+p->contextStackTop = 0;
+sqlite3DbFree(db, p->zErrMsg);
+p->zErrMsg = 0;
+p->pResultSet = 0;
+}
+/*
+** Set the number of result columns that will be returned by this SQL
+** statement. This is now set at compile time, rather than during
+** execution of the vdbe program so that sqlite3_column_count() can
+** be called on an SQL statement before sqlite3_step().
+*/
+void sqlite3VdbeSetNumCols(Vdbe *p, int nResColumn){
+Mem *pColName;
+int n;
+sqlite3 *db = p->db;
+releaseMemArray(p->aColName, p->nResColumn*COLNAME_N);
+sqlite3DbFree(db, p->aColName);
+n = nResColumn*COLNAME_N;
+p->nResColumn = nResColumn;
+p->aColName = pColName = (Mem*)sqlite3DbMallocZero(db, sizeof(Mem)*n );
+if( p->aColName==0 ) return;
+while( n-- > 0 ){
+pColName->flags = MEM_Null;
+pColName->db = p->db;
+pColName++;
+}
+}
+/*
+** Set the name of the idx'th column to be returned by the SQL statement.
+** zName must be a pointer to a nul terminated string.
+**
+** This call must be made after a call to sqlite3VdbeSetNumCols().
+**
+** If N==P4_STATIC  it means that zName is a pointer to a constant static
+** string and we can just copy the pointer. If it is P4_DYNAMIC, then
+** the string is freed using sqlite3DbFree(db, ) when the vdbe is finished with
+** it. Otherwise, N bytes of zName are copied.
+*/
+int sqlite3VdbeSetColName(Vdbe *p, int idx, int var, const char *zName, int N){
+int rc;
+Mem *pColName;
+assert( idx<p->nResColumn );
+assert( var<COLNAME_N );
+if( p->db->mallocFailed ) return SQLITE_NOMEM;
+assert( p->aColName!=0 );
+pColName = &(p->aColName[idx+var*p->nResColumn]);
+if( N==P4_DYNAMIC || N==P4_STATIC ){
+rc = sqlite3VdbeMemSetStr(pColName, zName, -1, SQLITE_UTF8, SQLITE_STATIC);
+}else{
+rc = sqlite3VdbeMemSetStr(pColName, zName, N, SQLITE_UTF8,SQLITE_TRANSIENT);
+}
+if( rc==SQLITE_OK && N==P4_DYNAMIC ){
+pColName->flags &= (~MEM_Static);
+pColName->zMalloc = pColName->z;
+}
+return rc;
+}
+/*
+** A read or write transaction may or may not be active on database handle
+** db. If a transaction is active, commit it. If there is a
+** write-transaction spanning more than one database file, this routine
+** takes care of the master journal trickery.
+*/
+static int vdbeCommit(sqlite3 *db, Vdbe *p){
+int i;
+int nTrans = 0;  /* Number of databases with an active write-transaction */
+int rc = SQLITE_OK;
+int needXcommit = 0;
+/* Before doing anything else, call the xSync() callback for any
+** virtual module tables written in this transaction. This has to
+** be done before determining whether a master journal file is
+** required, as an xSync() callback may add an attached database
+** to the transaction.
+*/
+rc = sqlite3VtabSync(db, &p->zErrMsg);
+if( rc!=SQLITE_OK ){
+return rc;
+}
+/* This loop determines (a) if the commit hook should be invoked and
+** (b) how many database files have open write transactions, not
+** including the temp database. (b) is important because if more than
+** one database file has an open write transaction, a master journal
+** file is required for an atomic commit.
+*/
+for(i=0; i<db->nDb; i++){
+Btree *pBt = db->aDb[i].pBt;
+if( sqlite3BtreeIsInTrans(pBt) ){
+needXcommit = 1;
+if( i!=1 ) nTrans++;
+}
+}
+/* If there are any write-transactions at all, invoke the commit hook */
+if( needXcommit && db->xCommitCallback ){
+(void)sqlite3SafetyOff(db);
+rc = db->xCommitCallback(db->pCommitArg);
+(void)sqlite3SafetyOn(db);
+if( rc ){
+return SQLITE_CONSTRAINT;
+}
+}
+/* The simple case - no more than one database file (not counting the
+** TEMP database) has a transaction active.   There is no need for the
+** master-journal.
+**
+** If the return value of sqlite3BtreeGetFilename() is a zero length
+** string, it means the main database is :memory: or a temp file.  In
+** that case we do not support atomic multi-file commits, so use the
+** simple case then too.
+*/
+if( 0==strlen(sqlite3BtreeGetFilename(db->aDb[0].pBt)) || nTrans<=1 ){
+for(i=0; rc==SQLITE_OK && i<db->nDb; i++){
+Btree *pBt = db->aDb[i].pBt;
+if( pBt ){
+rc = sqlite3BtreeCommitPhaseOne(pBt, 0);
+}
+}
+/* Do the commit only if all databases successfully complete phase 1.
+** If one of the BtreeCommitPhaseOne() calls fails, this indicates an
+** IO error while deleting or truncating a journal file. It is unlikely,
+** but could happen. In this case abandon processing and return the error.
+*/
+for(i=0; rc==SQLITE_OK && i<db->nDb; i++){
+Btree *pBt = db->aDb[i].pBt;
+if( pBt ){
+rc = sqlite3BtreeCommitPhaseTwo(pBt);
+}
+}
+if( rc==SQLITE_OK ){
+sqlite3VtabCommit(db);
+}
+}
+/* The complex case - There is a multi-file write-transaction active.
+** This requires a master journal file to ensure the transaction is
+** committed atomicly.
+*/
+#ifndef SQLITE_OMIT_DISKIO
+else{
+sqlite3_vfs *pVfs = db->pVfs;
+int needSync = 0;
+char *zMaster = 0;   /* File-name for the master journal */
+char const *zMainFile = sqlite3BtreeGetFilename(db->aDb[0].pBt);
+sqlite3_file *pMaster = 0;
+i64 offset = 0;
+int res;
+/* Select a master journal file name */
+do {
+u32 random;
+sqlite3DbFree(db, zMaster);
+sqlite3_randomness(sizeof(random), &random);
+zMaster = sqlite3MPrintf(db, "%s-mj%08X", zMainFile, random&0x7fffffff);
+if( !zMaster ){
+return SQLITE_NOMEM;
+}
+rc = sqlite3OsAccess(pVfs, zMaster, SQLITE_ACCESS_EXISTS, &res);
+}while( rc==SQLITE_OK && res );
+if( rc==SQLITE_OK ){
+/* Open the master journal. */
+rc = sqlite3OsOpenMalloc(pVfs, zMaster, &pMaster,
+SQLITE_OPEN_READWRITE|SQLITE_OPEN_CREATE|
+SQLITE_OPEN_EXCLUSIVE|SQLITE_OPEN_MASTER_JOURNAL, 0
+);
+}
+if( rc!=SQLITE_OK ){
+sqlite3DbFree(db, zMaster);
+return rc;
+}
+/* Write the name of each database file in the transaction into the new
+** master journal file. If an error occurs at this point close
+** and delete the master journal file. All the individual journal files
+** still have 'null' as the master journal pointer, so they will roll
+** back independently if a failure occurs.
+*/
+for(i=0; i<db->nDb; i++){
+Btree *pBt = db->aDb[i].pBt;
+if( i==1 ) continue;   /* Ignore the TEMP database */
+if( sqlite3BtreeIsInTrans(pBt) ){
+char const *zFile = sqlite3BtreeGetJournalname(pBt);
+if( zFile[0]==0 ) continue;  /* Ignore :memory: databases */
+if( !needSync && !sqlite3BtreeSyncDisabled(pBt) ){
+needSync = 1;
+}
+rc = sqlite3OsWrite(pMaster, zFile, strlen(zFile)+1, offset);
+offset += strlen(zFile)+1;
+if( rc!=SQLITE_OK ){
+sqlite3OsCloseFree(pMaster);
+sqlite3OsDelete(pVfs, zMaster, 0);
+sqlite3DbFree(db, zMaster);
+return rc;
+}
+}
+}
+/* Sync the master journal file. If the IOCAP_SEQUENTIAL device
+** flag is set this is not required.
+*/
+zMainFile = sqlite3BtreeGetDirname(db->aDb[0].pBt);
+if( (needSync
+&& (0==(sqlite3OsDeviceCharacteristics(pMaster)&SQLITE_IOCAP_SEQUENTIAL))
+&& (rc=sqlite3OsSync(pMaster, SQLITE_SYNC_NORMAL))!=SQLITE_OK) ){
+sqlite3OsCloseFree(pMaster);
+sqlite3OsDelete(pVfs, zMaster, 0);
+sqlite3DbFree(db, zMaster);
+return rc;
+}
+/* Sync all the db files involved in the transaction. The same call
+** sets the master journal pointer in each individual journal. If
+** an error occurs here, do not delete the master journal file.
+**
+** If the error occurs during the first call to
+** sqlite3BtreeCommitPhaseOne(), then there is a chance that the
+** master journal file will be orphaned. But we cannot delete it,
+** in case the master journal file name was written into the journal
+** file before the failure occured.
+*/
+for(i=0; rc==SQLITE_OK && i<db->nDb; i++){
+Btree *pBt = db->aDb[i].pBt;
+if( pBt ){
+rc = sqlite3BtreeCommitPhaseOne(pBt, zMaster);
+}
+}
+sqlite3OsCloseFree(pMaster);
+if( rc!=SQLITE_OK ){
+sqlite3DbFree(db, zMaster);
+return rc;
+}
+/* Delete the master journal file. This commits the transaction. After
+** doing this the directory is synced again before any individual
+** transaction files are deleted.
+*/
+rc = sqlite3OsDelete(pVfs, zMaster, 1);
+sqlite3DbFree(db, zMaster);
+zMaster = 0;
+if( rc ){
+return rc;
+}
+/* All files and directories have already been synced, so the following
+** calls to sqlite3BtreeCommitPhaseTwo() are only closing files and
+** deleting or truncating journals. If something goes wrong while
+** this is happening we don't really care. The integrity of the
+** transaction is already guaranteed, but some stray 'cold' journals
+** may be lying around. Returning an error code won't help matters.
+*/
+disable_simulated_io_errors();
+sqlite3BeginBenignMalloc();
+for(i=0; i<db->nDb; i++){
+Btree *pBt = db->aDb[i].pBt;
+if( pBt ){
+sqlite3BtreeCommitPhaseTwo(pBt);
+}
+}
+sqlite3EndBenignMalloc();
+enable_simulated_io_errors();
+sqlite3VtabCommit(db);
+}
+#endif
+return rc;
+}
+/*
+** This routine checks that the sqlite3.activeVdbeCnt count variable
+** matches the number of vdbe's in the list sqlite3.pVdbe that are
+** currently active. An assertion fails if the two counts do not match.
+** This is an internal self-check only - it is not an essential processing
+** step.
+**
+** This is a no-op if NDEBUG is defined.
+*/
+#ifndef NDEBUG
+static void checkActiveVdbeCnt(sqlite3 *db){
+Vdbe *p;
+int cnt = 0;
+p = db->pVdbe;
+while( p ){
+if( p->magic==VDBE_MAGIC_RUN && p->pc>=0 ){
+cnt++;
+}
+p = p->pNext;
+}
+assert( cnt==db->activeVdbeCnt );
+}
+#else
+#define checkActiveVdbeCnt(x)
+#endif
+/*
+** For every Btree that in database connection db which
+** has been modified, "trip" or invalidate each cursor in
+** that Btree might have been modified so that the cursor
+** can never be used again.  This happens when a rollback
+*** occurs.  We have to trip all the other cursors, even
+** cursor from other VMs in different database connections,
+** so that none of them try to use the data at which they
+** were pointing and which now may have been changed due
+** to the rollback.
+**
+** Remember that a rollback can delete tables complete and
+** reorder rootpages.  So it is not sufficient just to save
+** the state of the cursor.  We have to invalidate the cursor
+** so that it is never used again.
+*/
+static void invalidateCursorsOnModifiedBtrees(sqlite3 *db){
+int i;
+for(i=0; i<db->nDb; i++){
+Btree *p = db->aDb[i].pBt;
+if( p && sqlite3BtreeIsInTrans(p) ){
+sqlite3BtreeTripAllCursors(p, SQLITE_ABORT);
+}
+}
+}
+/*
+** This routine is called the when a VDBE tries to halt.  If the VDBE
+** has made changes and is in autocommit mode, then commit those
+** changes.  If a rollback is needed, then do the rollback.
+**
+** This routine is the only way to move the state of a VM from
+** SQLITE_MAGIC_RUN to SQLITE_MAGIC_HALT.  It is harmless to
+** call this on a VM that is in the SQLITE_MAGIC_HALT state.
+**
+** Return an error code.  If the commit could not complete because of
+** lock contention, return SQLITE_BUSY.  If SQLITE_BUSY is returned, it
+** means the close did not happen and needs to be repeated.
+*/
+int sqlite3VdbeHalt(Vdbe *p){
+sqlite3 *db = p->db;
+int i;
+int (*xFunc)(Btree *pBt) = 0;  /* Function to call on each btree backend */
+int isSpecialError;            /* Set to true if SQLITE_NOMEM or IOERR */
+/* This function contains the logic that determines if a statement or
+** transaction will be committed or rolled back as a result of the
+** execution of this virtual machine.
+**
+** If any of the following errors occur:
+**
+**     SQLITE_NOMEM
+**     SQLITE_IOERR
+**     SQLITE_FULL
+**     SQLITE_INTERRUPT
+**
+** Then the internal cache might have been left in an inconsistent
+** state.  We need to rollback the statement transaction, if there is
+** one, or the complete transaction if there is no statement transaction.
+*/
+if( p->db->mallocFailed ){
+p->rc = SQLITE_NOMEM;
+}
+closeAllCursorsExceptActiveVtabs(p);
+if( p->magic!=VDBE_MAGIC_RUN ){
+return SQLITE_OK;
+}
+checkActiveVdbeCnt(db);
+/* No commit or rollback needed if the program never started */
+if( p->pc>=0 ){
+int mrc;   /* Primary error code from p->rc */
+/* Lock all btrees used by the statement */
+sqlite3BtreeMutexArrayEnter(&p->aMutex);
+/* Check for one of the special errors */
+mrc = p->rc & 0xff;
+isSpecialError = mrc==SQLITE_NOMEM || mrc==SQLITE_IOERR
+|| mrc==SQLITE_INTERRUPT || mrc==SQLITE_FULL;
+if( isSpecialError ){
+/* This loop does static analysis of the query to see which of the
+** following three categories it falls into:
+**
+**     Read-only
+**     Query with statement journal
+**     Query without statement journal
+**
+** We could do something more elegant than this static analysis (i.e.
+** store the type of query as part of the compliation phase), but
+** handling malloc() or IO failure is a fairly obscure edge case so
+** this is probably easier. Todo: Might be an opportunity to reduce
+** code size a very small amount though...
+*/
+int notReadOnly = 0;
+int isStatement = 0;
+assert(p->aOp || p->nOp==0);
+for(i=0; i<p->nOp; i++){
+switch( p->aOp[i].opcode ){
+case OP_Transaction:
+notReadOnly |= p->aOp[i].p2;
+break;
+case OP_Statement:
+isStatement = 1;
+break;
+}
+}
+/* If the query was read-only, we need do no rollback at all. Otherwise,
+** proceed with the special handling.
+*/
+if( notReadOnly || mrc!=SQLITE_INTERRUPT ){
+if( p->rc==SQLITE_IOERR_BLOCKED && isStatement ){
+xFunc = sqlite3BtreeRollbackStmt;
+p->rc = SQLITE_BUSY;
+} else if( (mrc==SQLITE_NOMEM || mrc==SQLITE_FULL) && isStatement ){
+xFunc = sqlite3BtreeRollbackStmt;
+}else{
+/* We are forced to roll back the active transaction. Before doing
+** so, abort any other statements this handle currently has active.
+*/
+invalidateCursorsOnModifiedBtrees(db);
+sqlite3RollbackAll(db);
+db->autoCommit = 1;
+}
+}
+}
+/* If the auto-commit flag is set and this is the only active vdbe, then
+** we do either a commit or rollback of the current transaction.
+**
+** Note: This block also runs if one of the special errors handled
+** above has occured.
+*/
+if( db->autoCommit && db->activeVdbeCnt==1 ){
+if( p->rc==SQLITE_OK || (p->errorAction==OE_Fail && !isSpecialError) ){
+/* The auto-commit flag is true, and the vdbe program was
+** successful or hit an 'OR FAIL' constraint. This means a commit
+** is required.
+*/
+int rc = vdbeCommit(db, p);
+if( rc==SQLITE_BUSY ){
+sqlite3BtreeMutexArrayLeave(&p->aMutex);
+return SQLITE_BUSY;
+}else if( rc!=SQLITE_OK ){
+p->rc = rc;
+sqlite3RollbackAll(db);
+}else{
+sqlite3CommitInternalChanges(db);
+}
+}else{
+sqlite3RollbackAll(db);
+}
+}else if( !xFunc ){
+if( p->rc==SQLITE_OK || p->errorAction==OE_Fail ){
+if( p->openedStatement ){
+xFunc = sqlite3BtreeCommitStmt;
+}
+}else if( p->errorAction==OE_Abort ){
+xFunc = sqlite3BtreeRollbackStmt;
+}else{
+invalidateCursorsOnModifiedBtrees(db);
+sqlite3RollbackAll(db);
+db->autoCommit = 1;
+}
+}
+/* If xFunc is not NULL, then it is one of sqlite3BtreeRollbackStmt or
+** sqlite3BtreeCommitStmt. Call it once on each backend. If an error occurs
+** and the return code is still SQLITE_OK, set the return code to the new
+** error value.
+*/
+assert(!xFunc ||
+xFunc==sqlite3BtreeCommitStmt ||
+xFunc==sqlite3BtreeRollbackStmt
+);
+for(i=0; xFunc && i<db->nDb; i++){
+int rc;
+Btree *pBt = db->aDb[i].pBt;
+if( pBt ){
+rc = xFunc(pBt);
+if( rc && (p->rc==SQLITE_OK || p->rc==SQLITE_CONSTRAINT) ){
+p->rc = rc;
+sqlite3DbFree(db, p->zErrMsg);
+p->zErrMsg = 0;
+}
+}
+}
+/* If this was an INSERT, UPDATE or DELETE and the statement was committed,
+** set the change counter.
+*/
+if( p->changeCntOn && p->pc>=0 ){
+if( !xFunc || xFunc==sqlite3BtreeCommitStmt ){
+sqlite3VdbeSetChanges(db, p->nChange);
+}else{
+sqlite3VdbeSetChanges(db, 0);
+}
+p->nChange = 0;
+}
+/* Rollback or commit any schema changes that occurred. */
+if( p->rc!=SQLITE_OK && db->flags&SQLITE_InternChanges ){
+sqlite3ResetInternalSchema(db, 0);
+db->flags = (db->flags | SQLITE_InternChanges);
+}
+/* Release the locks */
+sqlite3BtreeMutexArrayLeave(&p->aMutex);
+}
+/* We have successfully halted and closed the VM.  Record this fact. */
+if( p->pc>=0 ){
+db->activeVdbeCnt--;
+}
+p->magic = VDBE_MAGIC_HALT;
+checkActiveVdbeCnt(db);
+if( p->db->mallocFailed ){
+p->rc = SQLITE_NOMEM;
+}
+return SQLITE_OK;
+}
+/*
+** Each VDBE holds the result of the most recent sqlite3_step() call
+** in p->rc.  This routine sets that result back to SQLITE_OK.
+*/
+void sqlite3VdbeResetStepResult(Vdbe *p){
+p->rc = SQLITE_OK;
+}
+/*
+** Clean up a VDBE after execution but do not delete the VDBE just yet.
+** Write any error messages into *pzErrMsg.  Return the result code.
+**
+** After this routine is run, the VDBE should be ready to be executed
+** again.
+**
+** To look at it another way, this routine resets the state of the
+** virtual machine from VDBE_MAGIC_RUN or VDBE_MAGIC_HALT back to
+** VDBE_MAGIC_INIT.
+*/
+int sqlite3VdbeReset(Vdbe *p){
+sqlite3 *db;
+db = p->db;
+/* If the VM did not run to completion or if it encountered an
+** error, then it might not have been halted properly.  So halt
+** it now.
+*/
+(void)sqlite3SafetyOn(db);
+sqlite3VdbeHalt(p);
+(void)sqlite3SafetyOff(db);
+/* If the VDBE has be run even partially, then transfer the error code
+** and error message from the VDBE into the main database structure.  But
+** if the VDBE has just been set to run but has not actually executed any
+** instructions yet, leave the main database error information unchanged.
+*/
+if( p->pc>=0 ){
+if( p->zErrMsg ){
+sqlite3BeginBenignMalloc();
+sqlite3ValueSetStr(db->pErr,-1,p->zErrMsg,SQLITE_UTF8,SQLITE_TRANSIENT);
+sqlite3EndBenignMalloc();
+db->errCode = p->rc;
+sqlite3DbFree(db, p->zErrMsg);
+p->zErrMsg = 0;
+}else if( p->rc ){
+sqlite3Error(db, p->rc, 0);
+}else{
+sqlite3Error(db, SQLITE_OK, 0);
+}
+}else if( p->rc && p->expired ){
+/* The expired flag was set on the VDBE before the first call
+** to sqlite3_step(). For consistency (since sqlite3_step() was
+** called), set the database error in this case as well.
+*/
+sqlite3Error(db, p->rc, 0);
+sqlite3ValueSetStr(db->pErr, -1, p->zErrMsg, SQLITE_UTF8, SQLITE_TRANSIENT);
+sqlite3DbFree(db, p->zErrMsg);
+p->zErrMsg = 0;
+}
+/* Reclaim all memory used by the VDBE
+*/
+Cleanup(p);
+/* Save profiling information from this VDBE run.
+*/
+#ifdef VDBE_PROFILE
+{
+FILE *out = fopen("vdbe_profile.out", "a");
+if( out ){
+int i;
+fprintf(out, "---- ");
+for(i=0; i<p->nOp; i++){
+fprintf(out, "%02x", p->aOp[i].opcode);
+}
+fprintf(out, "\n");
+for(i=0; i<p->nOp; i++){
+fprintf(out, "%6d %10lld %8lld ",
+p->aOp[i].cnt,
+p->aOp[i].cycles,
+p->aOp[i].cnt>0 ? p->aOp[i].cycles/p->aOp[i].cnt : 0
+);
+sqlite3VdbePrintOp(out, i, &p->aOp[i]);
+}
+fclose(out);
+}
+}
+#endif
+p->magic = VDBE_MAGIC_INIT;
+return p->rc & db->errMask;
+}
+/*
+** Clean up and delete a VDBE after execution.  Return an integer which is
+** the result code.  Write any error message text into *pzErrMsg.
+*/
+int sqlite3VdbeFinalize(Vdbe *p){
+int rc = SQLITE_OK;
+if( p->magic==VDBE_MAGIC_RUN || p->magic==VDBE_MAGIC_HALT ){
+rc = sqlite3VdbeReset(p);
+assert( (rc & p->db->errMask)==rc );
+}else if( p->magic!=VDBE_MAGIC_INIT ){
+return SQLITE_MISUSE;
+}
+sqlite3VdbeDelete(p);
+return rc;
+}
+/*
+** Call the destructor for each auxdata entry in pVdbeFunc for which
+** the corresponding bit in mask is clear.  Auxdata entries beyond 31
+** are always destroyed.  To destroy all auxdata entries, call this
+** routine with mask==0.
+*/
+void sqlite3VdbeDeleteAuxData(VdbeFunc *pVdbeFunc, int mask){
+int i;
+for(i=0; i<pVdbeFunc->nAux; i++){
+struct AuxData *pAux = &pVdbeFunc->apAux[i];
+if( (i>31 || !(mask&(1<<i))) && pAux->pAux ){
+if( pAux->xDelete ){
+pAux->xDelete(pAux->pAux);
+}
+pAux->pAux = 0;
+}
+}
+}
+/*
+** Delete an entire VDBE.
+*/
+void sqlite3VdbeDelete(Vdbe *p){
+int i;
+sqlite3 *db;
+if( p==0 ) return;
+db = p->db;
+if( p->pPrev ){
+p->pPrev->pNext = p->pNext;
+}else{
+assert( db->pVdbe==p );
+db->pVdbe = p->pNext;
+}
+if( p->pNext ){
+p->pNext->pPrev = p->pPrev;
+}
+if( p->aOp ){
+Op *pOp = p->aOp;
+for(i=0; i<p->nOp; i++, pOp++){
+freeP4(db, pOp->p4type, pOp->p4.p);
+#ifdef SQLITE_DEBUG
+sqlite3DbFree(db, pOp->zComment);
+#endif
+}
+sqlite3DbFree(db, p->aOp);
+}
+releaseMemArray(p->aVar, p->nVar);
+sqlite3DbFree(db, p->aLabel);
+if( p->aMem ){
+sqlite3DbFree(db, &p->aMem[1]);
+}
+releaseMemArray(p->aColName, p->nResColumn*COLNAME_N);
+sqlite3DbFree(db, p->aColName);
+sqlite3DbFree(db, p->zSql);
+p->magic = VDBE_MAGIC_DEAD;
+sqlite3DbFree(db, p);
+}
+/*
+** If a MoveTo operation is pending on the given cursor, then do that
+** MoveTo now.  Return an error code.  If no MoveTo is pending, this
+** routine does nothing and returns SQLITE_OK.
+*/
+int sqlite3VdbeCursorMoveto(Cursor *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 = keyToInt(p->movetoTarget);
+p->rowidIsValid = res==0;
+if( res<0 ){
+rc = sqlite3BtreeNext(p->pCursor, &res);
+if( rc ) return rc;
+}
+#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;
+p->nullRow = 1;
+}
+}
+return SQLITE_OK;
+}
+/*
+** The following functions:
+**
+** sqlite3VdbeSerialType()
+** sqlite3VdbeSerialTypeLen()
+** sqlite3VdbeSerialLen()
+** sqlite3VdbeSerialPut()
+** sqlite3VdbeSerialGet()
+**
+** encapsulate the code that serializes values for storage in SQLite
+** data and index records. Each serialized value consists of a
+** 'serial-type' and a blob of data. The serial type is an 8-byte unsigned
+** integer, stored as a varint.
+**
+** In an SQLite index record, the serial type is stored directly before
+** the blob of data that it corresponds to. In a table record, all serial
+** types are stored at the start of the record, and the blobs of data at
+** the end. Hence these functions allow the caller to handle the
+** serial-type and data blob seperately.
+**
+** The following table describes the various storage classes for data:
+**
+**   serial type        bytes of data      type
+**   --------------     ---------------    ---------------
+**      0                     0            NULL
+**      1                     1            signed integer
+**      2                     2            signed integer
+**      3                     3            signed integer
+**      4                     4            signed integer
+**      5                     6            signed integer
+**      6                     8            signed integer
+**      7                     8            IEEE float
+**      8                     0            Integer constant 0
+**      9                     0            Integer constant 1
+**     10,11                               reserved for expansion
+**    N>=12 and even       (N-12)/2        BLOB
+**    N>=13 and odd        (N-13)/2        text
+**
+** The 8 and 9 types were added in 3.3.0, file format 4.  Prior versions
+** of SQLite will not understand those serial types.
+*/
+/*
+** Return the serial-type for the value stored in pMem.
+*/
+u32 sqlite3VdbeSerialType(Mem *pMem, int file_format){
+int flags = pMem->flags;
+int n;
+if( flags&MEM_Null ){
+return 0;
+}
+if( flags&MEM_Int ){
+/* Figure out whether to use 1, 2, 4, 6 or 8 bytes. */
+#   define MAX_6BYTE ((((i64)0x00008000)<<32)-1)
+i64 i = pMem->u.i;
+u64 u;
+if( file_format>=4 && (i&1)==i ){
+return 8+i;
+}
+u = i<0 ? -i : i;
+if( u<=127 ) return 1;
+if( u<=32767 ) return 2;
+if( u<=8388607 ) return 3;
+if( u<=2147483647 ) return 4;
+if( u<=MAX_6BYTE ) return 5;
+return 6;
+}
+if( flags&MEM_Real ){
+return 7;
+}
+assert( flags&(MEM_Str|MEM_Blob) );
+n = pMem->n;
+if( flags & MEM_Zero ){
+n += pMem->u.i;
+}
+assert( n>=0 );
+return ((n*2) + 12 + ((flags&MEM_Str)!=0));
+}
+/*
+** Return the length of the data corresponding to the supplied serial-type.
+*/
+int sqlite3VdbeSerialTypeLen(u32 serial_type){
+if( serial_type>=12 ){
+return (serial_type-12)/2;
+}else{
+static const u8 aSize[] = { 0, 1, 2, 3, 4, 6, 8, 8, 0, 0, 0, 0 };
+return aSize[serial_type];
+}
+}
+/*
+** If we are on an architecture with mixed-endian floating
+** points (ex: ARM7) then swap the lower 4 bytes with the
+** upper 4 bytes.  Return the result.
+**
+** For most architectures, this is a no-op.
+**
+** (later):  It is reported to me that the mixed-endian problem
+** on ARM7 is an issue with GCC, not with the ARM7 chip.  It seems
+** that early versions of GCC stored the two words of a 64-bit
+** float in the wrong order.  And that error has been propagated
+** ever since.  The blame is not necessarily with GCC, though.
+** GCC might have just copying the problem from a prior compiler.
+** I am also told that newer versions of GCC that follow a different
+** ABI get the byte order right.
+**
+** Developers using SQLite on an ARM7 should compile and run their
+** application using -DSQLITE_DEBUG=1 at least once.  With DEBUG
+** enabled, some asserts below will ensure that the byte order of
+** floating point values is correct.
+**
+** (2007-08-30)  Frank van Vugt has studied this problem closely
+** and has send his findings to the SQLite developers.  Frank
+** writes that some Linux kernels offer floating point hardware
+** emulation that uses only 32-bit mantissas instead of a full
+** 48-bits as required by the IEEE standard.  (This is the
+** CONFIG_FPE_FASTFPE option.)  On such systems, floating point
+** byte swapping becomes very complicated.  To avoid problems,
+** the necessary byte swapping is carried out using a 64-bit integer
+** rather than a 64-bit float.  Frank assures us that the code here
+** works for him.  We, the developers, have no way to independently
+** verify this, but Frank seems to know what he is talking about
+** so we trust him.
+*/
+#ifdef SQLITE_MIXED_ENDIAN_64BIT_FLOAT
+static u64 floatSwap(u64 in){
+union {
+u64 r;
+u32 i[2];
+} u;
+u32 t;
+u.r = in;
+t = u.i[0];
+u.i[0] = u.i[1];
+u.i[1] = t;
+return u.r;
+}
+# define swapMixedEndianFloat(X)  X = floatSwap(X)
+#else
+# define swapMixedEndianFloat(X)
+#endif
+/*
+** Write the serialized data blob for the value stored in pMem into
+** buf. It is assumed that the caller has allocated sufficient space.
+** Return the number of bytes written.
+**
+** nBuf is the amount of space left in buf[].  nBuf must always be
+** large enough to hold the entire field.  Except, if the field is
+** a blob with a zero-filled tail, then buf[] might be just the right
+** size to hold everything except for the zero-filled tail.  If buf[]
+** is only big enough to hold the non-zero prefix, then only write that
+** prefix into buf[].  But if buf[] is large enough to hold both the
+** prefix and the tail then write the prefix and set the tail to all
+** zeros.
+**
+** Return the number of bytes actually written into buf[].  The number
+** of bytes in the zero-filled tail is included in the return value only
+** if those bytes were zeroed in buf[].
+*/
+int sqlite3VdbeSerialPut(u8 *buf, int nBuf, Mem *pMem, int file_format){
+u32 serial_type = sqlite3VdbeSerialType(pMem, file_format);
+int len;
+/* Integer and Real */
+if( serial_type<=7 && serial_type>0 ){
+u64 v;
+int i;
+if( serial_type==7 ){
+assert( sizeof(v)==sizeof(pMem->r) );
+memcpy(&v, &pMem->r, sizeof(v));
+swapMixedEndianFloat(v);
+}else{
+v = pMem->u.i;
+}
+len = i = sqlite3VdbeSerialTypeLen(serial_type);
+assert( len<=nBuf );
+while( i-- ){
+buf[i] = (v&0xFF);
+v >>= 8;
+}
+return len;
+}
+/* String or blob */
+if( serial_type>=12 ){
+assert( pMem->n + ((pMem->flags & MEM_Zero)?pMem->u.i:0)
+== sqlite3VdbeSerialTypeLen(serial_type) );
+assert( pMem->n<=nBuf );
+len = pMem->n;
+memcpy(buf, pMem->z, len);
+if( pMem->flags & MEM_Zero ){
+len += pMem->u.i;
+if( len>nBuf ){
+len = nBuf;
+}
+memset(&buf[pMem->n], 0, len-pMem->n);
+}
+return len;
+}
+/* NULL or constants 0 or 1 */
+return 0;
+}
+/*
+** 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.
+*/
+int sqlite3VdbeSerialGet(
+const unsigned char *buf,     /* Buffer to deserialize from */
+u32 serial_type,              /* Serial type to deserialize */
+Mem *pMem                     /* Memory cell to write value into */
+){
+switch( serial_type ){
+case 10:   /* Reserved for future use */
+case 11:   /* Reserved for future use */
+case 0: {  /* NULL */
+pMem->flags = MEM_Null;
+break;
+}
+case 1: { /* 1-byte signed integer */
+pMem->u.i = (signed char)buf[0];
+pMem->flags = MEM_Int;
+return 1;
+}
+case 2: { /* 2-byte signed integer */
+pMem->u.i = (((signed char)buf[0])<<8) | buf[1];
+pMem->flags = MEM_Int;
+return 2;
+}
+case 3: { /* 3-byte signed integer */
+pMem->u.i = (((signed char)buf[0])<<16) | (buf[1]<<8) | buf[2];
+pMem->flags = MEM_Int;
+return 3;
+}
+case 4: { /* 4-byte signed integer */
+pMem->u.i = (buf[0]<<24) | (buf[1]<<16) | (buf[2]<<8) | buf[3];
+pMem->flags = MEM_Int;
+return 4;
+}
+case 5: { /* 6-byte signed integer */
+u64 x = (((signed char)buf[0])<<8) | buf[1];
+u32 y = (buf[2]<<24) | (buf[3]<<16) | (buf[4]<<8) | buf[5];
+x = (x<<32) | y;
+pMem->u.i = *(i64*)&x;
+pMem->flags = MEM_Int;
+return 6;
+}
+case 6:   /* 8-byte signed integer */
+case 7: { /* IEEE floating point */
+u64 x;
+u32 y;
+#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 = (buf[0]<<24) | (buf[1]<<16) | (buf[2]<<8) | buf[3];
+y = (buf[4]<<24) | (buf[5]<<16) | (buf[6]<<8) | buf[7];
+x = (x<<32) | y;
+if( serial_type==6 ){
+pMem->u.i = *(i64*)&x;
+pMem->flags = MEM_Int;
+}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: {
+int len = (serial_type-12)/2;
+pMem->z = (char *)buf;
+pMem->n = len;
+pMem->xDel = 0;
+if( serial_type&0x01 ){
+pMem->flags = MEM_Str | MEM_Ephem;
+}else{
+pMem->flags = MEM_Blob | MEM_Ephem;
+}
+return len;
+}
+}
+return 0;
+}
+/*
+** Given the nKey-byte encoding of a record in pKey[], parse the
+** record into a UnpackedRecord structure.  Return a pointer to
+** that structure.
+**
+** The calling function might provide szSpace bytes of memory
+** space at pSpace.  This space can be used to hold the returned
+** VDbeParsedRecord structure if it is large enough.  If it is
+** not big enough, space is obtained from sqlite3_malloc().
+**
+** The returned structure should be closed by a call to
+** sqlite3VdbeDeleteUnpackedRecord().
+*/
+UnpackedRecord *sqlite3VdbeRecordUnpack(
+KeyInfo *pKeyInfo,     /* Information about the record format */
+int nKey,              /* Size of the binary record */
+const void *pKey,      /* The binary record */
+UnpackedRecord *pSpace,/* Space available to hold resulting object */
+int szSpace            /* Size of pSpace[] in bytes */
+){
+const unsigned char *aKey = (const unsigned char *)pKey;
+UnpackedRecord *p;
+int nByte;
+int idx, d;
+u16 u;                 /* Unsigned loop counter */
+u32 szHdr;
+Mem *pMem;
+assert( sizeof(Mem)>sizeof(*p) );
+nByte = sizeof(Mem)*(pKeyInfo->nField+2);
+if( nByte>szSpace ){
+p = sqlite3DbMallocRaw(pKeyInfo->db, nByte);
+if( p==0 ) return 0;
+p->flags = UNPACKED_NEED_FREE | UNPACKED_NEED_DESTROY;
+}else{
+p = pSpace;
+p->flags = UNPACKED_NEED_DESTROY;
+}
+p->pKeyInfo = pKeyInfo;
+p->nField = pKeyInfo->nField + 1;
+p->aMem = pMem = &((Mem*)p)[1];
+idx = getVarint32(aKey, szHdr);
+d = szHdr;
+u = 0;
+while( idx<szHdr && u<p->nField ){
+u32 serial_type;
+idx += getVarint32( aKey+idx, serial_type);
+if( d>=nKey && sqlite3VdbeSerialTypeLen(serial_type)>0 ) break;
+pMem->enc = pKeyInfo->enc;
+pMem->db = pKeyInfo->db;
+pMem->flags = 0;
+pMem->zMalloc = 0;
+d += sqlite3VdbeSerialGet(&aKey[d], serial_type, pMem);
+pMem++;
+u++;
+}
+assert( u<=pKeyInfo->nField + 1 );
+p->nField = u;
+return (void*)p;
+}
+/*
+** This routine destroys a UnpackedRecord object
+*/
+void sqlite3VdbeDeleteUnpackedRecord(UnpackedRecord *p){
+if( p ){
+if( p->flags & UNPACKED_NEED_DESTROY ){
+int i;
+Mem *pMem;
+for(i=0, pMem=p->aMem; i<p->nField; i++, pMem++){
+if( pMem->zMalloc ){
+sqlite3VdbeMemRelease(pMem);
+}
+}
+}
+if( p->flags & UNPACKED_NEED_FREE ){
+sqlite3DbFree(p->pKeyInfo->db, p);
+}
+}
+}
+/*
+** This function compares the two table rows or index records
+** specified by {nKey1, pKey1} and pPKey2.  It returns a negative, zero
+** or positive integer if key1 is less than, equal to or
+** greater than key2.  The {nKey1, pKey1} key must be a blob
+** created by th OP_MakeRecord opcode of the VDBE.  The pPKey2
+** key must be a parsed key such as obtained from
+** sqlite3VdbeParseRecord.
+**
+** Key1 and Key2 do not have to contain the same number of fields.
+** The key with fewer fields is usually compares less than the
+** longer key.  However if the UNPACKED_INCRKEY flags in pPKey2 is set
+** and the common prefixes are equal, then key1 is less than key2.
+** Or if the UNPACKED_MATCH_PREFIX flag is set and the prefixes are
+** equal, then the keys are considered to be equal and
+** the parts beyond the common prefix are ignored.
+**
+** If the UNPACKED_IGNORE_ROWID flag is set, then the last byte of
+** the header of pKey1 is ignored.  It is assumed that pKey1 is
+** an index key, and thus ends with a rowid value.  The last byte
+** of the header will therefore be the serial type of the rowid:
+** one of 1, 2, 3, 4, 5, 6, 8, or 9 - the integer serial types.
+** The serial type of the final rowid will always be a single byte.
+** By ignoring this last byte of the header, we force the comparison
+** to ignore the rowid at the end of key1.
+*/
+int sqlite3VdbeRecordCompare(
+int nKey1, const void *pKey1, /* Left key */
+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 nField;
+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;
+mem1.zMalloc = 0;
+idx1 = getVarint32(aKey1, szHdr1);
+d1 = szHdr1;
+if( pPKey2->flags & UNPACKED_IGNORE_ROWID ){
+szHdr1--;
+}
+nField = pKeyInfo->nField;
+while( idx1<szHdr1 && i<pPKey2->nField ){
+u32 serial_type1;
+/* Read the serial types for the next element in each key. */
+idx1 += getVarint32( aKey1+idx1, serial_type1 );
+if( d1>=nKey1 && sqlite3VdbeSerialTypeLen(serial_type1)>0 ) break;
+/* Extract the values to be compared.
+*/
+d1 += sqlite3VdbeSerialGet(&aKey1[d1], serial_type1, &mem1);
+/* Do the comparison
+*/
+rc = sqlite3MemCompare(&mem1, &pPKey2->aMem[i],
+i<nField ? pKeyInfo->aColl[i] : 0);
+if( rc!=0 ){
+break;
+}
+i++;
+}
+if( mem1.zMalloc ) sqlite3VdbeMemRelease(&mem1);
+if( rc==0 ){
+/* rc==0 here means that one of the keys ran out of fields and
+** all the fields up to that point were equal. If the UNPACKED_INCRKEY
+** flag is set, then break the tie by treating key2 as larger.
+** If the UPACKED_PREFIX_MATCH flag is set, then keys with common prefixes
+** are considered to be equal.  Otherwise, the longer key is the
+** larger.  As it happens, the pPKey2 will always be the longer
+** if there is a difference.
+*/
+if( pPKey2->flags & UNPACKED_INCRKEY ){
+rc = -1;
+}else if( pPKey2->flags & UNPACKED_PREFIX_MATCH ){
+/* Leave rc==0 */
+}else if( idx1<szHdr1 ){
+rc = 1;
+}
+}else if( pKeyInfo->aSortOrder && i<pKeyInfo->nField
+&& pKeyInfo->aSortOrder[i] ){
+rc = -rc;
+}
+return rc;
+}
+/*
+** pCur points at an index entry created using the OP_MakeRecord opcode.
+** Read the rowid (the last field in the record) and store it in *rowid.
+** Return SQLITE_OK if everything works, or an error code otherwise.
+*/
+int sqlite3VdbeIdxRowid(BtCursor *pCur, i64 *rowid){
+i64 nCellKey = 0;
+int rc;
+u32 szHdr;        /* Size of the header */
+u32 typeRowid;    /* Serial type of the rowid */
+u32 lenRowid;     /* Size of the rowid */
+Mem m, v;
+sqlite3BtreeKeySize(pCur, &nCellKey);
+if( nCellKey<=0 ){
+return SQLITE_CORRUPT_BKPT;
+}
+m.flags = 0;
+m.db = 0;
+m.zMalloc = 0;
+rc = sqlite3VdbeMemFromBtree(pCur, 0, nCellKey, 1, &m);
+if( rc ){
+return rc;
+}
+(void)getVarint32((u8*)m.z, szHdr);
+(void)getVarint32((u8*)&m.z[szHdr-1], typeRowid);
+lenRowid = sqlite3VdbeSerialTypeLen(typeRowid);
+sqlite3VdbeSerialGet((u8*)&m.z[m.n-lenRowid], typeRowid, &v);
+*rowid = v.u.i;
+sqlite3VdbeMemRelease(&m);
+return SQLITE_OK;
+}
+/*
+** Compare the key of the index entry that cursor pC is point to against
+** the key string in pKey (of length nKey).  Write into *pRes a number
+** that is negative, zero, or positive if pC is less than, equal to,
+** or greater than pKey.  Return SQLITE_OK on success.
+**
+** pKey is either created without a rowid or is truncated so that it
+** omits the rowid at the end.  The rowid at the end of the index entry
+** is ignored as well.  Hence, this routine only compares the prefixes
+** of the keys prior to the final rowid, not the entire key.
+**
+** pUnpacked may be an unpacked version of pKey,nKey.  If pUnpacked is
+** supplied it is used in place of pKey,nKey.
+*/
+int sqlite3VdbeIdxKeyCompare(
+Cursor *pC,                 /* The cursor to compare against */
+UnpackedRecord *pUnpacked,  /* Unpacked version of pKey and nKey */
+int *res                    /* Write the comparison result here */
+){
+i64 nCellKey = 0;
+int rc;
+BtCursor *pCur = pC->pCursor;
+Mem m;
+sqlite3BtreeKeySize(pCur, &nCellKey);
+if( nCellKey<=0 ){
+*res = 0;
+return SQLITE_OK;
+}
+m.db = 0;
+m.flags = 0;
+m.zMalloc = 0;
+rc = sqlite3VdbeMemFromBtree(pC->pCursor, 0, nCellKey, 1, &m);
+if( rc ){
+return rc;
+}
+assert( pUnpacked->flags & UNPACKED_IGNORE_ROWID );
+*res = sqlite3VdbeRecordCompare(m.n, m.z, pUnpacked);
+sqlite3VdbeMemRelease(&m);
+return SQLITE_OK;
+}
+/*
+** This routine sets the value to be returned by subsequent calls to
+** sqlite3_changes() on the database handle 'db'.
+*/
+void sqlite3VdbeSetChanges(sqlite3 *db, int nChange){
+assert( sqlite3_mutex_held(db->mutex) );
+db->nChange = nChange;
+db->nTotalChange += nChange;
+}
+/*
+** Set a flag in the vdbe to update the change counter when it is finalised
+** or reset.
+*/
+void sqlite3VdbeCountChanges(Vdbe *v){
+v->changeCntOn = 1;
+}
+/*
+** Mark every prepared statement associated with a database connection
+** as expired.
+**
+** An expired statement means that recompilation of the statement is
+** recommend.  Statements expire when things happen that make their
+** programs obsolete.  Removing user-defined functions or collating
+** sequences, or changing an authorization function are the types of
+** things that make prepared statements obsolete.
+*/
+void sqlite3ExpirePreparedStatements(sqlite3 *db){
+Vdbe *p;
+for(p = db->pVdbe; p; p=p->pNext){
+p->expired = 1;
+}
+}
+/*
+** Return the database associated with the Vdbe.
+*/
+sqlite3 *sqlite3VdbeDb(Vdbe *v){
+return v->db;
+}