FCL/sf/mw/web: comparison webengine/webkitutils/SqliteSymbian/vdbeaux.c

equal deleted inserted replaced

--1:000000000000
+:dd21522fd290
+/*
+** 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.
+*/
+#include "sqliteInt.h"
+#include "os.h"
+#include <ctype.h>
+#include "vdbeInt.h"
+/*
+** When debugging the code generator in a symbolic debugger, one can
+** set the sqlite3_vdbe_addop_trace to 1 and all opcodes will be printed
+** as they are added to the instruction stream.
+*/
+#ifdef SQLITE_DEBUG
+int sqlite3_vdbe_addop_trace = 0;
+#endif
+/*
+** Create a new virtual database engine.
+*/
+Vdbe *sqlite3VdbeCreate(sqlite3 *db){
+Vdbe *p;
+p = sqliteMalloc( 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;
+}
+/*
+** Turn tracing on or off
+*/
+void sqlite3VdbeTrace(Vdbe *p, FILE *trace){
+p->trace = trace;
+}
+/*
+** Resize the Vdbe.aOp array so that it contains at least N
+** elements. If the Vdbe is in VDBE_MAGIC_RUN state, then
+** the Vdbe.aOp array will be sized to contain exactly N
+** elements. Vdbe.nOpAlloc is set to reflect the new size of
+** the array.
+**
+** 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){
+int runMode = p->magic==VDBE_MAGIC_RUN;
+if( runMode || p->nOpAlloc<N ){
+VdbeOp *pNew;
+int nNew = N + 100*(!runMode);
+int oldSize = p->nOpAlloc;
+pNew = sqliteRealloc(p->aOp, nNew*sizeof(Op));
+if( pNew ){
+p->nOpAlloc = nNew;
+p->aOp = pNew;
+if( nNew>oldSize ){
+memset(&p->aOp[oldSize], 0, (nNew-oldSize)*sizeof(Op));
+}
+}
+}
+}
+/*
+** 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          First two of the three possible operands.
+**
+** Use the sqlite3VdbeResolveLabel() function to fix an address and
+** the sqlite3VdbeChangeP3() function to change the value of the P3
+** operand.
+*/
+int sqlite3VdbeAddOp(Vdbe *p, int op, int p1, int p2){
+int i;
+VdbeOp *pOp;
+i = p->nOp;
+p->nOp++;
+assert( p->magic==VDBE_MAGIC_INIT );
+if( p->nOpAlloc<=i ){
+resizeOpArray(p, i+1);
+if( sqlite3MallocFailed() ){
+return 0;
+}
+}
+pOp = &p->aOp[i];
+pOp->opcode = op;
+pOp->p1 = p1;
+pOp->p2 = p2;
+pOp->p3 = 0;
+pOp->p3type = P3_NOTUSED;
+p->expired = 0;
+#ifdef SQLITE_DEBUG
+if( sqlite3_vdbe_addop_trace ) sqlite3VdbePrintOp(0, i, &p->aOp[i]);
+#endif
+return i;
+}
+/*
+** Add an opcode that includes the p3 value.
+*/
+int sqlite3VdbeOp3(Vdbe *p, int op, int p1, int p2, const char *zP3,int p3type){
+int addr = sqlite3VdbeAddOp(p, op, p1, p2);
+sqlite3VdbeChangeP3(p, addr, zP3, p3type);
+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;
+sqliteReallocOrFree((void**)&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;
+}
+}
+/*
+** Return non-zero if opcode 'op' is guarenteed not to push more values
+** onto the VDBE stack than it pops off.
+*/
+static int opcodeNoPush(u8 op){
+/* The 10 NOPUSH_MASK_n constants are defined in the automatically
+** generated header file opcodes.h. Each is a 16-bit bitmask, one
+** bit corresponding to each opcode implemented by the virtual
+** machine in vdbe.c. The bit is true if the word "no-push" appears
+** in a comment on the same line as the "case OP_XXX:" in
+** sqlite3VdbeExec() in vdbe.c.
+**
+** If the bit is true, then the corresponding opcode is guarenteed not
+** to grow the stack when it is executed. Otherwise, it may grow the
+** stack by at most one entry.
+**
+** NOPUSH_MASK_0 corresponds to opcodes 0 to 15. NOPUSH_MASK_1 contains
+** one bit for opcodes 16 to 31, and so on.
+**
+** 16-bit bitmasks (rather than 32-bit) are specified in opcodes.h
+** because the file is generated by an awk program. Awk manipulates
+** all numbers as floating-point and we don't want to risk a rounding
+** error if someone builds with an awk that uses (for example) 32-bit
+** IEEE floats.
+*/
+static const u32 masks[5] = {
+NOPUSH_MASK_0 + (((unsigned)NOPUSH_MASK_1)<<16),
+NOPUSH_MASK_2 + (((unsigned)NOPUSH_MASK_3)<<16),
+NOPUSH_MASK_4 + (((unsigned)NOPUSH_MASK_5)<<16),
+NOPUSH_MASK_6 + (((unsigned)NOPUSH_MASK_7)<<16),
+NOPUSH_MASK_8 + (((unsigned)NOPUSH_MASK_9)<<16)
+};
+assert( op<32*5 );
+return (masks[op>>5] & (1<<(op&0x1F)));
+}
+#ifndef NDEBUG
+int sqlite3VdbeOpcodeNoPush(u8 op){
+return opcodeNoPush(op);
+}
+#endif
+/*
+** Loop through the program looking for P2 values that are negative.
+** 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.
+**
+** The integer *pMaxStack is set to the maximum number of vdbe stack
+** entries that static analysis reveals this program might need.
+**
+** This routine also does the following optimization:  It scans for
+** Halt instructions where P1==SQLITE_CONSTRAINT or P2==OE_Abort or for
+** IdxInsert instructions where P2!=0.  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 *pMaxStack){
+int i;
+int nMaxArgs = 0;
+int nMaxStack = p->nOp;
+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
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+|| opcode==OP_VUpdate
+#endif
+){
+if( pOp->p2>nMaxArgs ) nMaxArgs = pOp->p2;
+}else 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_VFilter ){
+int n;
+assert( p->nOp - i >= 3 );
+assert( pOp[-2].opcode==OP_Integer );
+n = pOp[-2].p1;
+if( n>nMaxArgs ) nMaxArgs = n;
+}
+if( opcodeNoPush(opcode) ){
+nMaxStack--;
+}
+if( pOp->p2>=0 ) continue;
+assert( -1-pOp->p2<p->nLabel );
+pOp->p2 = aLabel[-1-pOp->p2];
+}
+sqliteFree(p->aLabel);
+p->aLabel = 0;
+*pMaxFuncArgs = nMaxArgs;
+*pMaxStack = nMaxStack;
+/* 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 );
+resizeOpArray(p, p->nOp + nOp);
+if( sqlite3MallocFailed() ){
+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;
+pOut->p2 = p2<0 ? addr + ADDR(p2) : p2;
+pOut->p3 = pIn->p3;
+pOut->p3type = pIn->p3 ? P3_STATIC : P3_NOTUSED;
+#ifdef SQLITE_DEBUG
+if( sqlite3_vdbe_addop_trace ){
+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( val>=0 );
+assert( p==0 || p->magic==VDBE_MAGIC_INIT );
+if( p && addr>=0 && p->nOp>addr && p->aOp ){
+p->aOp[addr].p2 = 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(FuncDef *pDef){
+if( pDef && (pDef->flags & SQLITE_FUNC_EPHEM)!=0 ){
+sqliteFree(pDef);
+}
+}
+/*
+** Delete a P3 value if necessary.
+*/
+static void freeP3(int p3type, void *p3){
+if( p3 ){
+switch( p3type ){
+case P3_DYNAMIC:
+case P3_KEYINFO:
+case P3_KEYINFO_HANDOFF: {
+sqliteFree(p3);
+break;
+}
+case P3_MPRINTF: {
+sqlite3_free(p3);
+break;
+}
+case P3_VDBEFUNC: {
+VdbeFunc *pVdbeFunc = (VdbeFunc *)p3;
+freeEphemeralFunction(pVdbeFunc->pFunc);
+sqlite3VdbeDeleteAuxData(pVdbeFunc, 0);
+sqliteFree(pVdbeFunc);
+break;
+}
+case P3_FUNCDEF: {
+freeEphemeralFunction((FuncDef*)p3);
+break;
+}
+case P3_MEM: {
+sqlite3ValueFree((sqlite3_value*)p3);
+break;
+}
+}
+}
+}
+/*
+** Change N opcodes starting at addr to No-ops.
+*/
+void sqlite3VdbeChangeToNoop(Vdbe *p, int addr, int N){
+VdbeOp *pOp = &p->aOp[addr];
+while( N-- ){
+freeP3(pOp->p3type, pOp->p3);
+memset(pOp, 0, sizeof(pOp[0]));
+pOp->opcode = OP_Noop;
+pOp++;
+}
+}
+/*
+** Change the value of the P3 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 P3 operand is dynamic, meaning that a copy of
+** the string is made into memory obtained from sqliteMalloc().
+** A value of n==0 means copy bytes of zP3 up to and including the
+** first null byte.  If n>0 then copy n+1 bytes of zP3.
+**
+** If n==P3_KEYINFO it means that zP3 is a pointer to a KeyInfo structure.
+** A copy is made of the KeyInfo structure into memory obtained from
+** sqliteMalloc, to be freed when the Vdbe is finalized.
+** n==P3_KEYINFO_HANDOFF indicates that zP3 points to a KeyInfo structure
+** stored in memory that the caller has obtained from sqliteMalloc. The
+** caller should not free the allocation, it will be freed when the Vdbe is
+** finalized.
+**
+** Other values of n (P3_STATIC, P3_COLLSEQ etc.) indicate that zP3 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 P3 on the most recently inserted instruction.
+*/
+void sqlite3VdbeChangeP3(Vdbe *p, int addr, const char *zP3, int n){
+Op *pOp;
+assert( p==0 || p->magic==VDBE_MAGIC_INIT );
+if( p==0 || p->aOp==0 || sqlite3MallocFailed() ){
+if (n != P3_KEYINFO) {
+freeP3(n, (void*)*(char**)&zP3);
+}
+return;
+}
+if( addr<0 || addr>=p->nOp ){
+addr = p->nOp - 1;
+if( addr<0 ) return;
+}
+pOp = &p->aOp[addr];
+freeP3(pOp->p3type, pOp->p3);
+pOp->p3 = 0;
+if( zP3==0 ){
+pOp->p3 = 0;
+pOp->p3type = P3_NOTUSED;
+}else if( n==P3_KEYINFO ){
+KeyInfo *pKeyInfo;
+int nField, nByte;
+nField = ((KeyInfo*)zP3)->nField;
+nByte = sizeof(*pKeyInfo) + (nField-1)*sizeof(pKeyInfo->aColl[0]) + nField;
+pKeyInfo = sqliteMallocRaw( nByte );
+pOp->p3 = (char*)pKeyInfo;
+if( pKeyInfo ){
+unsigned char *aSortOrder;
+memcpy(pKeyInfo, zP3, nByte);
+aSortOrder = pKeyInfo->aSortOrder;
+if( aSortOrder ){
+pKeyInfo->aSortOrder = (unsigned char*)&pKeyInfo->aColl[nField];
+memcpy(pKeyInfo->aSortOrder, aSortOrder, nField);
+}
+pOp->p3type = P3_KEYINFO;
+}else{
+pOp->p3type = P3_NOTUSED;
+}
+}else if( n==P3_KEYINFO_HANDOFF ){
+pOp->p3 = (char*)zP3;
+pOp->p3type = P3_KEYINFO;
+}else if( n<0 ){
+pOp->p3 = (char*)zP3;
+pOp->p3type = n;
+}else{
+if( n==0 ) n = strlen(zP3);
+pOp->p3 = sqliteStrNDup(zP3, n);
+pOp->p3type = P3_DYNAMIC;
+}
+}
+#ifndef NDEBUG
+/*
+** Replace the P3 field of the most recently coded instruction with
+** comment text.
+*/
+void sqlite3VdbeComment(Vdbe *p, const char *zFormat, ...){
+va_list ap;
+assert( p->nOp>0 );
+assert( p->aOp==0 || p->aOp[p->nOp-1].p3==0
+|| sqlite3MallocFailed() );
+va_start(ap, zFormat);
+sqlite3VdbeChangeP3(p, -1, sqlite3VMPrintf(zFormat, ap), P3_DYNAMIC);
+va_end(ap);
+}
+#endif
+/*
+** 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 );
+return &p->aOp[addr];
+}
+#if !defined(SQLITE_OMIT_EXPLAIN) || !defined(NDEBUG) \
+|| defined(VDBE_PROFILE) || defined(SQLITE_DEBUG)
+/*
+** Compute a string that describes the P3 parameter for an opcode.
+** Use zTemp for any required temporary buffer space.
+*/
+static char *displayP3(Op *pOp, char *zTemp, int nTemp){
+char *zP3;
+assert( nTemp>=20 );
+switch( pOp->p3type ){
+case P3_KEYINFO: {
+int i, j;
+KeyInfo *pKeyInfo = (KeyInfo*)pOp->p3;
+sprintf(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 ){
+strcpy(&zTemp[i],",...");
+break;
+}
+zTemp[i++] = ',';
+if( pKeyInfo->aSortOrder && pKeyInfo->aSortOrder[j] ){
+zTemp[i++] = '-';
+}
+strcpy(&zTemp[i], pColl->zName);
+i += n;
+}else if( i+4<nTemp-6 ){
+strcpy(&zTemp[i],",nil");
+i += 4;
+}
+}
+zTemp[i++] = ')';
+zTemp[i] = 0;
+assert( i<nTemp );
+zP3 = zTemp;
+break;
+}
+case P3_COLLSEQ: {
+CollSeq *pColl = (CollSeq*)pOp->p3;
+sprintf(zTemp, "collseq(%.20s)", pColl->zName);
+zP3 = zTemp;
+break;
+}
+case P3_FUNCDEF: {
+FuncDef *pDef = (FuncDef*)pOp->p3;
+sqlite3_snprintf(nTemp, zTemp, "%s(%d)", pDef->zName, pDef->nArg);
+zP3 = zTemp;
+break;
+}
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+case P3_VTAB: {
+sqlite3_vtab *pVtab = (sqlite3_vtab*)pOp->p3;
+sqlite3_snprintf(nTemp, zTemp, "vtab:%p:%p", pVtab, pVtab->pModule);
+zP3 = zTemp;
+break;
+}
+#endif
+default: {
+zP3 = pOp->p3;
+if( zP3==0 || pOp->opcode==OP_Noop ){
+zP3 = "";
+}
+}
+}
+assert( zP3!=0 );
+return zP3;
+}
+#endif
+#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 *zP3;
+char zPtr[50];
+static const char *zFormat1 = "%4d %-13s %4d %4d %s\n";
+if( pOut==0 ) pOut = stdout;
+zP3 = displayP3(pOp, zPtr, sizeof(zPtr));
+fprintf(pOut, zFormat1,
+pc, sqlite3OpcodeNames[pOp->opcode], pOp->p1, pOp->p2, zP3);
+fflush(pOut);
+}
+#endif
+/*
+** Release an array of N Mem elements
+*/
+static void releaseMemArray(Mem *p, int N){
+if( p ){
+while( N-->0 ){
+sqlite3VdbeMemRelease(p++);
+}
+}
+}
+#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".
+*/
+int sqlite3VdbeList(
+Vdbe *p                   /* The VDBE */
+){
+sqlite3 *db = p->db;
+int i;
+int rc = SQLITE_OK;
+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 put dynamic strings onto the
+** the stack, they may become dynamic if the user calls
+** sqlite3_column_text16(), causing a translation to UTF-16 encoding.
+*/
+if( p->pTos==&p->aStack[4] ){
+releaseMemArray(p->aStack, 5);
+}
+p->resOnStack = 0;
+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, sqlite3ErrStr(p->rc), (char*)0);
+}else{
+Op *pOp = &p->aOp[i];
+Mem *pMem = p->aStack;
+pMem->flags = MEM_Int;
+pMem->type = SQLITE_INTEGER;
+pMem->i = i;                                /* Program counter */
+pMem++;
+pMem->flags = MEM_Static|MEM_Str|MEM_Term;
+pMem->z = sqlite3OpcodeNames[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->i = pOp->p1;                          /* P1 */
+pMem->type = SQLITE_INTEGER;
+pMem++;
+pMem->flags = MEM_Int;
+pMem->i = pOp->p2;                          /* P2 */
+pMem->type = SQLITE_INTEGER;
+pMem++;
+pMem->flags = MEM_Ephem|MEM_Str|MEM_Term;   /* P3 */
+pMem->z = displayP3(pOp, pMem->zShort, sizeof(pMem->zShort));
+assert( pMem->z!=0 );
+pMem->n = strlen(pMem->z);
+pMem->type = SQLITE_TEXT;
+pMem->enc = SQLITE_UTF8;
+p->nResColumn = 5 - 2*(p->explain-1);
+p->pTos = pMem;
+p->rc = SQLITE_OK;
+p->resOnStack = 1;
+rc = SQLITE_ROW;
+}
+return rc;
+}
+#endif /* SQLITE_OMIT_EXPLAIN */
+/*
+** Print the SQL that was used to generate a VDBE program.
+*/
+void sqlite3VdbePrintSql(Vdbe *p){
+#ifdef SQLITE_DEBUG
+int nOp = p->nOp;
+VdbeOp *pOp;
+if( nOp<1 ) return;
+pOp = &p->aOp[nOp-1];
+if( pOp->opcode==OP_Noop && pOp->p3!=0 ){
+const char *z = pOp->p3;
+while( isspace(*(u8*)z) ) z++;
+printf("SQL: [%s]\n", z);
+}
+#endif
+}
+/*
+** 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;
+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;
+/* No instruction ever pushes more than a single element onto the
+** stack.  And the stack never grows on successive executions of the
+** same loop.  So the total number of instructions is an upper bound
+** on the maximum stack depth required.  (Added later:)  The
+** resolveP2Values() call computes a tighter upper bound on the
+** stack size.
+**
+** Allocation all the stack space we will ever need.
+*/
+if( p->aStack==0 ){
+int nArg;       /* Maximum number of args passed to a user function. */
+int nStack;     /* Maximum number of stack entries required */
+resolveP2Values(p, &nArg, &nStack);
+resizeOpArray(p, p->nOp);
+assert( nVar>=0 );
+assert( nStack<p->nOp );
+if( isExplain ){
+nStack = 10;
+}
+p->aStack = sqliteMalloc(
+nStack*sizeof(p->aStack[0])    /* aStack */
++ nArg*sizeof(Mem*)              /* apArg */
++ nVar*sizeof(Mem)               /* aVar */
++ nVar*sizeof(char*)             /* azVar */
++ nMem*sizeof(Mem)               /* aMem */
++ nCursor*sizeof(Cursor*)        /* apCsr */
+);
+if( !sqlite3MallocFailed() ){
+p->aMem = &p->aStack[nStack];
+p->nMem = nMem;
+p->aVar = &p->aMem[nMem];
+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;
+}
+}
+}
+for(n=0; n<p->nMem; n++){
+p->aMem[n].flags = MEM_Null;
+}
+#ifdef SQLITE_DEBUG
+if( (p->db->flags & SQLITE_VdbeListing)!=0
+|| sqlite3OsFileExists("vdbe_explain")
+){
+int i;
+printf("VDBE Program Listing:\n");
+sqlite3VdbePrintSql(p);
+for(i=0; i<p->nOp; i++){
+sqlite3VdbePrintOp(stdout, i, &p->aOp[i]);
+}
+}
+if( sqlite3OsFileExists("vdbe_trace") ){
+p->trace = stdout;
+}
+#endif
+p->pTos = &p->aStack[-1];
+p->pc = -1;
+p->rc = SQLITE_OK;
+p->uniqueCnt = 0;
+p->returnDepth = 0;
+p->errorAction = OE_Abort;
+p->popStack =  0;
+p->explain |= isExplain;
+p->magic = VDBE_MAGIC_RUN;
+p->nChange = 0;
+p->cacheCtr = 1;
+p->minWriteFileFormat = 255;
+#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 cursor and release all the resources that cursor happens
+** to hold.
+*/
+void sqlite3VdbeFreeCursor(Vdbe *p, Cursor *pCx){
+if( pCx==0 ){
+return;
+}
+if( pCx->pCursor ){
+sqlite3BtreeCloseCursor(pCx->pCursor);
+}
+if( pCx->pBt ){
+sqlite3BtreeClose(pCx->pBt);
+}
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+if( pCx->pVtabCursor ){
+sqlite3_vtab_cursor *pVtabCursor = pCx->pVtabCursor;
+const sqlite3_module *pModule = pCx->pModule;
+p->inVtabMethod = 1;
+sqlite3SafetyOff(p->db);
+pModule->xClose(pVtabCursor);
+sqlite3SafetyOn(p->db);
+p->inVtabMethod = 0;
+}
+#endif
+sqliteFree(pCx->pData);
+sqliteFree(pCx->aType);
+sqliteFree(pCx);
+}
+/*
+** Close all cursors
+*/
+static void closeAllCursors(Vdbe *p){
+int i;
+if( p->apCsr==0 ) return;
+for(i=0; i<p->nCursor; i++){
+if( !p->inVtabMethod || (p->apCsr[i] && !p->apCsr[i]->pVtabCursor) ){
+sqlite3VdbeFreeCursor(p, p->apCsr[i]);
+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;
+if( p->aStack ){
+releaseMemArray(p->aStack, 1 + (p->pTos - p->aStack));
+p->pTos = &p->aStack[-1];
+}
+closeAllCursors(p);
+releaseMemArray(p->aMem, p->nMem);
+sqlite3VdbeFifoClear(&p->sFifo);
+if( p->contextStack ){
+for(i=0; i<p->contextStackTop; i++){
+sqlite3VdbeFifoClear(&p->contextStack[i].sFifo);
+}
+sqliteFree(p->contextStack);
+}
+p->contextStack = 0;
+p->contextStackDepth = 0;
+p->contextStackTop = 0;
+sqliteFree(p->zErrMsg);
+p->zErrMsg = 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;
+releaseMemArray(p->aColName, p->nResColumn*COLNAME_N);
+sqliteFree(p->aColName);
+n = nResColumn*COLNAME_N;
+p->nResColumn = nResColumn;
+p->aColName = pColName = (Mem*)sqliteMalloc( sizeof(Mem)*n );
+if( p->aColName==0 ) return;
+while( n-- > 0 ){
+(pColName++)->flags = MEM_Null;
+}
+}
+/*
+** 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==P3_STATIC  it means that zName is a pointer to a constant static
+** string and we can just copy the pointer. If it is P3_DYNAMIC, then
+** the string is freed using sqliteFree() 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( sqlite3MallocFailed() ) return SQLITE_NOMEM;
+assert( p->aColName!=0 );
+pColName = &(p->aColName[idx+var*p->nResColumn]);
+if( N==P3_DYNAMIC || N==P3_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==P3_DYNAMIC ){
+pColName->flags = (pColName->flags&(~MEM_Static))|MEM_Dyn;
+pColName->xDel = 0;
+}
+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){
+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, rc);
+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( pBt && sqlite3BtreeIsInTrans(pBt) ){
+needXcommit = 1;
+if( i!=1 ) nTrans++;
+}
+}
+/* If there are any write-transactions at all, invoke the commit hook */
+if( needXcommit && db->xCommitCallback ){
+sqlite3SafetyOff(db);
+rc = db->xCommitCallback(db->pCommitArg);
+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:.  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 = sqlite3BtreeSync(pBt, 0);
+}
+}
+/* Do the commit only if all databases successfully synced */
+if( rc==SQLITE_OK ){
+for(i=0; i<db->nDb; i++){
+Btree *pBt = db->aDb[i].pBt;
+if( pBt ){
+sqlite3BtreeCommit(pBt);
+}
+}
+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{
+int needSync = 0;
+char *zMaster = 0;   /* File-name for the master journal */
+char const *zMainFile = sqlite3BtreeGetFilename(db->aDb[0].pBt);
+OsFile *master = 0;
+/* Select a master journal file name */
+do {
+u32 random;
+sqliteFree(zMaster);
+sqlite3Randomness(sizeof(random), &random);
+zMaster = sqlite3MPrintf("%s-mj%08X", zMainFile, random&0x7fffffff);
+if( !zMaster ){
+return SQLITE_NOMEM;
+}
+}while( sqlite3OsFileExists(zMaster) );
+/* Open the master journal. */
+rc = sqlite3OsOpenExclusive(zMaster, &master, 0);
+if( rc!=SQLITE_OK ){
+sqliteFree(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( pBt && sqlite3BtreeIsInTrans(pBt) ){
+char const *zFile = sqlite3BtreeGetJournalname(pBt);
+if( zFile[0]==0 ) continue;  /* Ignore :memory: databases */
+if( !needSync && !sqlite3BtreeSyncDisabled(pBt) ){
+needSync = 1;
+}
+rc = sqlite3OsWrite(master, zFile, strlen(zFile)+1);
+if( rc!=SQLITE_OK ){
+sqlite3OsClose(&master);
+sqlite3OsDelete(zMaster);
+sqliteFree(zMaster);
+return rc;
+}
+}
+}
+/* Sync the master journal file. Before doing this, open the directory
+** the master journal file is store in so that it gets synced too.
+*/
+zMainFile = sqlite3BtreeGetDirname(db->aDb[0].pBt);
+rc = sqlite3OsOpenDirectory(master, zMainFile);
+if( rc!=SQLITE_OK ||
+(needSync && (rc=sqlite3OsSync(master,0))!=SQLITE_OK) ){
+sqlite3OsClose(&master);
+sqlite3OsDelete(zMaster);
+sqliteFree(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 sqlite3BtreeSync(),
+** 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 && sqlite3BtreeIsInTrans(pBt) ){
+rc = sqlite3BtreeSync(pBt, zMaster);
+}
+}
+sqlite3OsClose(&master);
+if( rc!=SQLITE_OK ){
+sqliteFree(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(zMaster);
+if( rc ){
+return rc;
+}
+sqliteFree(zMaster);
+zMaster = 0;
+rc = sqlite3OsSyncDirectory(zMainFile);
+if( rc!=SQLITE_OK ){
+/* This is not good. The master journal file has been deleted, but
+** the directory sync failed. There is no completely safe course of
+** action from here. The individual journals contain the name of the
+** master journal file, but there is no way of knowing if that
+** master journal exists now or if it will exist after the operating
+** system crash that may follow the fsync() failure.
+*/
+return rc;
+}
+/* All files and directories have already been synced, so the following
+** calls to sqlite3BtreeCommit() are only closing files and deleting
+** 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.
+*/
+for(i=0; i<db->nDb; i++){
+Btree *pBt = db->aDb[i].pBt;
+if( pBt ){
+sqlite3BtreeCommit(pBt);
+}
+}
+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
+/*
+** Find every active VM other than pVdbe and change its status to
+** aborted.  This happens when one VM causes a rollback due to an
+** ON CONFLICT ROLLBACK clause (for example).  The other VMs must be
+** aborted so that they do not have data rolled out from underneath
+** them leading to a segfault.
+*/
+void sqlite3AbortOtherActiveVdbes(sqlite3 *db, Vdbe *pExcept){
+Vdbe *pOther;
+for(pOther=db->pVdbe; pOther; pOther=pOther->pNext){
+if( pOther==pExcept ) continue;
+if( pOther->magic!=VDBE_MAGIC_RUN || pOther->pc<0 ) continue;
+checkActiveVdbeCnt(db);
+closeAllCursors(pOther);
+checkActiveVdbeCnt(db);
+pOther->aborted = 1;
+}
+}
+/*
+** 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.
+**
+** 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.
+**
+** Special errors:
+**
+**     If an SQLITE_NOMEM error has occured in a statement that writes to
+**     the database, then either a statement or transaction must be rolled
+**     back to ensure the tree-structures are in a consistent state. A
+**     statement transaction is rolled back if one is open, otherwise the
+**     entire transaction must be rolled back.
+**
+**     If an SQLITE_IOERR error has occured in a statement that writes to
+**     the database, then the entire transaction must be rolled back. The
+**     I/O error may have caused garbage to be written to the journal
+**     file. Were the transaction to continue and eventually be rolled
+**     back that garbage might end up in the database file.
+**
+**     In both of the above cases, the Vdbe.errorAction variable is
+**     ignored. If the sqlite3.autoCommit flag is false and a transaction
+**     is rolled back, it will be set to true.
+**
+** Other errors:
+**
+** No error:
+**
+*/
+if( sqlite3MallocFailed() ){
+p->rc = SQLITE_NOMEM;
+}
+if( p->magic!=VDBE_MAGIC_RUN ){
+/* Already halted.  Nothing to do. */
+assert( p->magic==VDBE_MAGIC_HALT );
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+closeAllCursors(p);
+#endif
+return SQLITE_OK;
+}
+closeAllCursors(p);
+checkActiveVdbeCnt(db);
+/* No commit or rollback needed if the program never started */
+if( p->pc>=0 ){
+/* Check for one of the special errors - SQLITE_NOMEM or SQLITE_IOERR */
+isSpecialError = ((p->rc==SQLITE_NOMEM || p->rc==SQLITE_IOERR)?1:0);
+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 isReadOnly = 1;
+int isStatement = 0;
+assert(p->aOp || p->nOp==0);
+for(i=0; i<p->nOp; i++){
+switch( p->aOp[i].opcode ){
+case OP_Transaction:
+isReadOnly = 0;
+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( !isReadOnly ){
+if( p->rc==SQLITE_NOMEM && 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.
+*/
+sqlite3AbortOtherActiveVdbes(db, p);
+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);
+if( rc==SQLITE_BUSY ){
+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 ){
+xFunc = sqlite3BtreeCommitStmt;
+}else if( p->errorAction==OE_Abort ){
+xFunc = sqlite3BtreeRollbackStmt;
+}else{
+sqlite3AbortOtherActiveVdbes(db, p);
+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;
+sqlite3SetString(&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);
+}
+}
+/* We have successfully halted and closed the VM.  Record this fact. */
+if( p->pc>=0 ){
+db->activeVdbeCnt--;
+}
+p->magic = VDBE_MAGIC_HALT;
+checkActiveVdbeCnt(db);
+return 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){
+if( p->magic!=VDBE_MAGIC_RUN && p->magic!=VDBE_MAGIC_HALT ){
+sqlite3Error(p->db, SQLITE_MISUSE, 0);
+return SQLITE_MISUSE;
+}
+/* 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.
+*/
+sqlite3SafetyOn(p->db);
+sqlite3VdbeHalt(p);
+sqlite3SafetyOff(p->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 ){
+sqlite3* db = p->db;
+sqlite3ValueSetStr(db->pErr, -1, p->zErrMsg, SQLITE_UTF8, sqlite3FreeX);
+db->errCode = p->rc;
+p->zErrMsg = 0;
+}else if( p->rc ){
+sqlite3Error(p->db, p->rc, 0);
+}else{
+sqlite3Error(p->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(p->db, p->rc, 0);
+}
+/* Reclaim all memory used by the VDBE
+*/
+Cleanup(p);
+/* Save profiling information from this VDBE run.
+*/
+assert( p->pTos<&p->aStack[p->pc<0?0:p->pc] || !p->aStack );
+#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;
+p->aborted = 0;
+if( p->rc==SQLITE_SCHEMA ){
+sqlite3ResetInternalSchema(p->db, 0);
+}
+return p->rc;
+}
+/*
+** 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);
+}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;
+if( p==0 ) return;
+Cleanup(p);
+if( p->pPrev ){
+p->pPrev->pNext = p->pNext;
+}else{
+assert( p->db->pVdbe==p );
+p->db->pVdbe = p->pNext;
+}
+if( p->pNext ){
+p->pNext->pPrev = p->pPrev;
+}
+if( p->aOp ){
+for(i=0; i<p->nOp; i++){
+Op *pOp = &p->aOp[i];
+freeP3(pOp->p3type, pOp->p3);
+}
+sqliteFree(p->aOp);
+}
+releaseMemArray(p->aVar, p->nVar);
+sqliteFree(p->aLabel);
+sqliteFree(p->aStack);
+releaseMemArray(p->aColName, p->nResColumn*COLNAME_N);
+sqliteFree(p->aColName);
+p->magic = VDBE_MAGIC_DEAD;
+sqliteFree(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;
+extern int sqlite3_search_count;
+assert( p->isTable );
+if( p->isTable ){
+rc = sqlite3BtreeMoveto(p->pCursor, 0, p->movetoTarget, &res);
+}else{
+rc = sqlite3BtreeMoveto(p->pCursor,(char*)&p->movetoTarget,
+sizeof(i64),&res);
+}
+if( rc ) return rc;
+*p->pIncrKey = 0;
+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;
+}
+return SQLITE_OK;
+}
+/*
+** The following functions:
+**
+** sqlite3VdbeSerialType()
+** sqlite3VdbeSerialTypeLen()
+** sqlite3VdbeSerialRead()
+** sqlite3VdbeSerialLen()
+** sqlite3VdbeSerialWrite()
+**
+** 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;
+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)0x00001000)<<32)-1)
+i64 i = pMem->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;
+}
+if( flags&MEM_Str ){
+int n = pMem->n;
+assert( n>=0 );
+return ((n*2) + 13);
+}
+if( flags&MEM_Blob ){
+return (pMem->n*2 + 12);
+}
+return 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];
+}
+}
+/*
+** 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.
+*/
+int sqlite3VdbeSerialPut(unsigned char *buf, 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 ){
+v = *(u64*)&pMem->r;
+}else{
+v = *(u64*)&pMem->i;
+}
+len = i = sqlite3VdbeSerialTypeLen(serial_type);
+while( i-- ){
+buf[i] = (v&0xFF);
+v >>= 8;
+}
+return len;
+}
+/* String or blob */
+if( serial_type>=12 ){
+len = sqlite3VdbeSerialTypeLen(serial_type);
+memcpy(buf, pMem->z, len);
+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->i = (signed char)buf[0];
+pMem->flags = MEM_Int;
+return 1;
+}
+case 2: { /* 2-byte signed integer */
+pMem->i = (((signed char)buf[0])<<8) | buf[1];
+pMem->flags = MEM_Int;
+return 2;
+}
+case 3: { /* 3-byte signed integer */
+pMem->i = (((signed char)buf[0])<<16) | (buf[1]<<8) | buf[2];
+pMem->flags = MEM_Int;
+return 3;
+}
+case 4: { /* 4-byte signed integer */
+pMem->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->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.  The byte order differs on some (broken) architectures.
+*/
+static const u64 t1 = ((u64)0x3ff00000)<<32;
+assert( 1.0==*(double*)&t1 );
+#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->i = *(i64*)&x;
+pMem->flags = MEM_Int;
+}else{
+pMem->r = *(double*)&x;
+pMem->flags = MEM_Real;
+}
+return 8;
+}
+case 8:    /* Integer 0 */
+case 9: {  /* Integer 1 */
+pMem->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;
+}
+/*
+** 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 macro takes advantage this fact to provide a fast 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 = GetVarint( A, B );
+**
+*/
+#define GetVarint(A,B)  ((B = *(A))<=0x7f ? 1 : sqlite3GetVarint32(A, &B))
+/*
+** This function compares the two table rows or index records specified by
+** {nKey1, pKey1} and {nKey2, pKey2}, returning a negative, zero
+** or positive integer if {nKey1, pKey1} is less than, equal to or
+** greater than {nKey2, pKey2}.  Both Key1 and Key2 must be byte strings
+** composed by the OP_MakeRecord opcode of the VDBE.
+*/
+int sqlite3VdbeRecordCompare(
+void *userData,
+int nKey1, const void *pKey1,
+int nKey2, const void *pKey2
+){
+KeyInfo *pKeyInfo = (KeyInfo*)userData;
+u32 d1, d2;          /* Offset into aKey[] of next data element */
+u32 idx1, idx2;      /* Offset into aKey[] of next header element */
+u32 szHdr1, szHdr2;  /* Number of bytes in header */
+int i = 0;
+int nField;
+int rc = 0;
+const unsigned char *aKey1 = (const unsigned char *)pKey1;
+const unsigned char *aKey2 = (const unsigned char *)pKey2;
+Mem mem1;
+Mem mem2;
+mem1.enc = pKeyInfo->enc;
+mem2.enc = pKeyInfo->enc;
+idx1 = GetVarint(aKey1, szHdr1);
+d1 = szHdr1;
+idx2 = GetVarint(aKey2, szHdr2);
+d2 = szHdr2;
+nField = pKeyInfo->nField;
+while( idx1<szHdr1 && idx2<szHdr2 ){
+u32 serial_type1;
+u32 serial_type2;
+/* Read the serial types for the next element in each key. */
+idx1 += GetVarint( aKey1+idx1, serial_type1 );
+if( d1>=nKey1 && sqlite3VdbeSerialTypeLen(serial_type1)>0 ) break;
+idx2 += GetVarint( aKey2+idx2, serial_type2 );
+if( d2>=nKey2 && sqlite3VdbeSerialTypeLen(serial_type2)>0 ) break;
+/* Assert that there is enough space left in each key for the blob of
+** data to go with the serial type just read. This assert may fail if
+** the file is corrupted.  Then read the value from each key into mem1
+** and mem2 respectively.
+*/
+d1 += sqlite3VdbeSerialGet(&aKey1[d1], serial_type1, &mem1);
+d2 += sqlite3VdbeSerialGet(&aKey2[d2], serial_type2, &mem2);
+rc = sqlite3MemCompare(&mem1, &mem2, i<nField ? pKeyInfo->aColl[i] : 0);
+if( mem1.flags & MEM_Dyn ) sqlite3VdbeMemRelease(&mem1);
+if( mem2.flags & MEM_Dyn ) sqlite3VdbeMemRelease(&mem2);
+if( rc!=0 ){
+break;
+}
+i++;
+}
+/* One of the keys ran out of fields, but all the fields up to that point
+** were equal. If the incrKey flag is true, then the second key is
+** treated as larger.
+*/
+if( rc==0 ){
+if( pKeyInfo->incrKey ){
+rc = -1;
+}else if( d1<nKey1 ){
+rc = 1;
+}else if( d2<nKey2 ){
+rc = -1;
+}
+}else if( pKeyInfo->aSortOrder && i<pKeyInfo->nField
+&& pKeyInfo->aSortOrder[i] ){
+rc = -rc;
+}
+return rc;
+}
+/*
+** The argument is an index entry composed using the OP_MakeRecord opcode.
+** The last entry in this record should be an integer (specifically
+** an integer rowid).  This routine returns the number of bytes in
+** that integer.
+*/
+int sqlite3VdbeIdxRowidLen(const u8 *aKey){
+u32 szHdr;        /* Size of the header */
+u32 typeRowid;    /* Serial type of the rowid */
+sqlite3GetVarint32(aKey, &szHdr);
+sqlite3GetVarint32(&aKey[szHdr-1], &typeRowid);
+return sqlite3VdbeSerialTypeLen(typeRowid);
+}
+/*
+** 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;
+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;
+}
+rc = sqlite3VdbeMemFromBtree(pCur, 0, nCellKey, 1, &m);
+if( rc ){
+return rc;
+}
+sqlite3GetVarint32((u8*)m.z, &szHdr);
+sqlite3GetVarint32((u8*)&m.z[szHdr-1], &typeRowid);
+lenRowid = sqlite3VdbeSerialTypeLen(typeRowid);
+sqlite3VdbeSerialGet((u8*)&m.z[m.n-lenRowid], typeRowid, &v);
+*rowid = v.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.
+*/
+int sqlite3VdbeIdxKeyCompare(
+Cursor *pC,                 /* The cursor to compare against */
+int nKey, const u8 *pKey,   /* The key to compare */
+int *res                    /* Write the comparison result here */
+){
+i64 nCellKey;
+int rc;
+BtCursor *pCur = pC->pCursor;
+int lenRowid;
+Mem m;
+sqlite3BtreeKeySize(pCur, &nCellKey);
+if( nCellKey<=0 ){
+*res = 0;
+return SQLITE_OK;
+}
+rc = sqlite3VdbeMemFromBtree(pC->pCursor, 0, nCellKey, 1, &m);
+if( rc ){
+return rc;
+}
+lenRowid = sqlite3VdbeIdxRowidLen((u8*)m.z);
+*res = sqlite3VdbeRecordCompare(pC->pKeyInfo, m.n-lenRowid, m.z, nKey, pKey);
+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){
+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;
+}