MCL/sf/app/podcatcher: comparison engine/sqlite/src/vdbe.cpp

equal deleted inserted replaced

-:5f8e5adbbed9
+:29cda98b007e
+/*
+** 2001 September 15
+**
+** 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.
+**
+*************************************************************************
+** The code in this file implements execution method of the
+** Virtual Database Engine (VDBE).  A separate file ("vdbeaux.c")
+** handles housekeeping details such as creating and deleting
+** VDBE instances.  This file is solely interested in executing
+** the VDBE program.
+**
+** In the external interface, an "sqlite3_stmt*" is an opaque pointer
+** to a VDBE.
+**
+** The SQL parser generates a program which is then executed by
+** the VDBE to do the work of the SQL statement.  VDBE programs are
+** similar in form to assembly language.  The program consists of
+** a linear sequence of operations.  Each operation has an opcode
+** and 3 operands.  Operands P1 and P2 are integers.  Operand P3
+** is a null-terminated string.   The P2 operand must be non-negative.
+** Opcodes will typically ignore one or more operands.  Many opcodes
+** ignore all three operands.
+**
+** Computation results are stored on a stack.  Each entry on the
+** stack is either an integer, a null-terminated string, a floating point
+** number, or the SQL "NULL" value.  An inplicit conversion from one
+** type to the other occurs as necessary.
+**
+** Most of the code in this file is taken up by the sqlite3VdbeExec()
+** function which does the work of interpreting a VDBE program.
+** But other routines are also provided to help in building up
+** a program instruction by instruction.
+**
+** Various scripts scan this source file in order to generate HTML
+** documentation, headers files, or other derived files.  The formatting
+** of the code in this file is, therefore, important.  See other comments
+** in this file for details.  If in doubt, do not deviate from existing
+** commenting and indentation practices when changing or adding code.
+**
+** $Id: vdbe.cpp 1282 2008-11-13 09:31:33Z LarsPson $
+*/
+#include "sqliteInt.h"
+#include <ctype.h>
+#include "vdbeInt.h"
+/*
+** The following global variable is incremented every time a cursor
+** moves, either by the OP_MoveXX, OP_Next, or OP_Prev opcodes.  The test
+** procedures use this information to make sure that indices are
+** working correctly.  This variable has no function other than to
+** help verify the correct operation of the library.
+*/
+#ifdef SQLITE_TEST
+int sqlite3_search_count = 0;
+#endif
+/*
+** When this global variable is positive, it gets decremented once before
+** each instruction in the VDBE.  When reaches zero, the u1.isInterrupted
+** field of the sqlite3 structure is set in order to simulate and interrupt.
+**
+** This facility is used for testing purposes only.  It does not function
+** in an ordinary build.
+*/
+#ifdef SQLITE_TEST
+int sqlite3_interrupt_count = 0;
+#endif
+/*
+** The next global variable is incremented each type the OP_Sort opcode
+** is executed.  The test procedures use this information to make sure that
+** sorting is occurring or not occuring at appropriate times.   This variable
+** has no function other than to help verify the correct operation of the
+** library.
+*/
+#ifdef SQLITE_TEST
+int sqlite3_sort_count = 0;
+#endif
+/*
+** The next global variable records the size of the largest MEM_Blob
+** or MEM_Str that has appeared on the VDBE stack.  The test procedures
+** use this information to make sure that the zero-blob functionality
+** is working correctly.   This variable has no function other than to
+** help verify the correct operation of the library.
+*/
+#ifdef SQLITE_TEST
+int sqlite3_max_blobsize = 0;
+#endif
+/*
+** Release the memory associated with the given stack level.  This
+** leaves the Mem.flags field in an inconsistent state.
+*/
+#define Release(P) if((P)->flags&MEM_Dyn){ sqlite3VdbeMemRelease(P); }
+/*
+** Convert the given stack entity into a string if it isn't one
+** already. Return non-zero if a malloc() fails.
+*/
+#define Stringify(P, enc) \
+if(((P)->flags&(MEM_Str|MEM_Blob))==0 && sqlite3VdbeMemStringify(P,enc)) \
+{ goto no_mem; }
+/*
+** 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))
+/*
+** An ephemeral string value (signified by the MEM_Ephem flag) contains
+** a pointer to a dynamically allocated string where some other entity
+** is responsible for deallocating that string.  Because the stack entry
+** does not control the string, it might be deleted without the stack
+** entry knowing it.
+**
+** This routine converts an ephemeral string into a dynamically allocated
+** string that the stack entry itself controls.  In other words, it
+** converts an MEM_Ephem string into an MEM_Dyn string.
+*/
+#define Deephemeralize(P) \
+if( ((P)->flags&MEM_Ephem)!=0 \
+&& sqlite3VdbeMemMakeWriteable(P) ){ goto no_mem;}
+/*
+** Call sqlite3VdbeMemExpandBlob() on the supplied value (type Mem*)
+** P if required.
+*/
+#define ExpandBlob(P) (((P)->flags&MEM_Zero)?sqlite3VdbeMemExpandBlob(P):0)
+/*
+** Argument pMem points at a memory cell that will be passed to a
+** user-defined function or returned to the user as the result of a query.
+** The second argument, 'db_enc' is the text encoding used by the vdbe for
+** stack variables.  This routine sets the pMem->enc and pMem->type
+** variables used by the sqlite3_value_*() routines.
+*/
+#define storeTypeInfo(A,B) _storeTypeInfo(A)
+static void _storeTypeInfo(Mem *pMem){
+int flags = pMem->flags;
+if( flags & MEM_Null ){
+pMem->type = SQLITE_NULL;
+}
+else if( flags & MEM_Int ){
+pMem->type = SQLITE_INTEGER;
+}
+else if( flags & MEM_Real ){
+pMem->type = SQLITE_FLOAT;
+}
+else if( flags & MEM_Str ){
+pMem->type = SQLITE_TEXT;
+}else{
+pMem->type = SQLITE_BLOB;
+}
+}
+/*
+** Pop the stack N times.
+*/
+static void popStack(Mem **ppTos, int N){
+Mem *pTos = *ppTos;
+while( N>0 ){
+N--;
+Release(pTos);
+pTos--;
+}
+*ppTos = pTos;
+}
+/*
+** Allocate cursor number iCur.  Return a pointer to it.  Return NULL
+** if we run out of memory.
+*/
+static Cursor *allocateCursor(Vdbe *p, int iCur, int iDb){
+Cursor *pCx;
+assert( iCur<p->nCursor );
+if( p->apCsr[iCur] ){
+sqlite3VdbeFreeCursor(p, p->apCsr[iCur]);
+}
+p->apCsr[iCur] = pCx = (Cursor*)sqlite3MallocZero( sizeof(Cursor) );
+if( pCx ){
+pCx->iDb = iDb;
+}
+return pCx;
+}
+/*
+** Try to convert a value into a numeric representation if we can
+** do so without loss of information.  In other words, if the string
+** looks like a number, convert it into a number.  If it does not
+** look like a number, leave it alone.
+*/
+static void applyNumericAffinity(Mem *pRec){
+if( (pRec->flags & (MEM_Real|MEM_Int))==0 ){
+int realnum;
+sqlite3VdbeMemNulTerminate(pRec);
+if( (pRec->flags&MEM_Str)
+&& sqlite3IsNumber(pRec->z, &realnum, pRec->enc) ){
+i64 value;
+sqlite3VdbeChangeEncoding(pRec, SQLITE_UTF8);
+if( !realnum && sqlite3Atoi64(pRec->z, &value) ){
+sqlite3VdbeMemRelease(pRec);
+pRec->u.i = value;
+pRec->flags = MEM_Int;
+}else{
+sqlite3VdbeMemRealify(pRec);
+}
+}
+}
+}
+/*
+** Processing is determine by the affinity parameter:
+**
+** SQLITE_AFF_INTEGER:
+** SQLITE_AFF_REAL:
+** SQLITE_AFF_NUMERIC:
+**    Try to convert pRec to an integer representation or a
+**    floating-point representation if an integer representation
+**    is not possible.  Note that the integer representation is
+**    always preferred, even if the affinity is REAL, because
+**    an integer representation is more space efficient on disk.
+**
+** SQLITE_AFF_TEXT:
+**    Convert pRec to a text representation.
+**
+** SQLITE_AFF_NONE:
+**    No-op.  pRec is unchanged.
+*/
+static void applyAffinity(
+Mem *pRec,          /* The value to apply affinity to */
+char affinity,      /* The affinity to be applied */
+u8 enc              /* Use this text encoding */
+){
+if( affinity==SQLITE_AFF_TEXT ){
+/* Only attempt the conversion to TEXT if there is an integer or real
+** representation (blob and NULL do not get converted) but no string
+** representation.
+*/
+if( 0==(pRec->flags&MEM_Str) && (pRec->flags&(MEM_Real|MEM_Int)) ){
+sqlite3VdbeMemStringify(pRec, enc);
+}
+pRec->flags &= ~(MEM_Real|MEM_Int);
+}else if( affinity!=SQLITE_AFF_NONE ){
+assert( affinity==SQLITE_AFF_INTEGER || affinity==SQLITE_AFF_REAL
+|| affinity==SQLITE_AFF_NUMERIC );
+applyNumericAffinity(pRec);
+if( pRec->flags & MEM_Real ){
+sqlite3VdbeIntegerAffinity(pRec);
+}
+}
+}
+/*
+** Try to convert the type of a function argument or a result column
+** into a numeric representation.  Use either INTEGER or REAL whichever
+** is appropriate.  But only do the conversion if it is possible without
+** loss of information and return the revised type of the argument.
+**
+** This is an EXPERIMENTAL api and is subject to change or removal.
+*/
+EXPORT_C int sqlite3_value_numeric_type(sqlite3_value *pVal){
+Mem *pMem = (Mem*)pVal;
+applyNumericAffinity(pMem);
+storeTypeInfo(pMem, 0);
+return pMem->type;
+}
+/*
+** Exported version of applyAffinity(). This one works on sqlite3_value*,
+** not the internal Mem* type.
+*/
+void sqlite3ValueApplyAffinity(
+sqlite3_value *pVal,
+u8 affinity,
+u8 enc
+){
+applyAffinity((Mem *)pVal, affinity, enc);
+}
+#ifdef SQLITE_DEBUG
+/*
+** Write a nice string representation of the contents of cell pMem
+** into buffer zBuf, length nBuf.
+*/
+void sqlite3VdbeMemPrettyPrint(Mem *pMem, char *zBuf){
+char *zCsr = zBuf;
+int f = pMem->flags;
+static const char *const encnames[] = {"(X)", "(8)", "(16LE)", "(16BE)"};
+if( f&MEM_Blob ){
+int i;
+char c;
+if( f & MEM_Dyn ){
+c = 'z';
+assert( (f & (MEM_Static|MEM_Ephem))==0 );
+}else if( f & MEM_Static ){
+c = 't';
+assert( (f & (MEM_Dyn|MEM_Ephem))==0 );
+}else if( f & MEM_Ephem ){
+c = 'e';
+assert( (f & (MEM_Static|MEM_Dyn))==0 );
+}else{
+c = 's';
+}
+sqlite3_snprintf(100, zCsr, "%c", c);
+zCsr += strlen(zCsr);
+sqlite3_snprintf(100, zCsr, "%d[", pMem->n);
+zCsr += strlen(zCsr);
+for(i=0; i<16 && i<pMem->n; i++){
+sqlite3_snprintf(100, zCsr, "%02X", ((int)pMem->z[i] & 0xFF));
+zCsr += strlen(zCsr);
+}
+for(i=0; i<16 && i<pMem->n; i++){
+char z = pMem->z[i];
+if( z<32 || z>126 ) *zCsr++ = '.';
+else *zCsr++ = z;
+}
+sqlite3_snprintf(100, zCsr, "]%s", encnames[pMem->enc]);
+zCsr += strlen(zCsr);
+if( f & MEM_Zero ){
+sqlite3_snprintf(100, zCsr,"+%lldz",pMem->u.i);
+zCsr += strlen(zCsr);
+}
+*zCsr = '\0';
+}else if( f & MEM_Str ){
+int j, k;
+zBuf[0] = ' ';
+if( f & MEM_Dyn ){
+zBuf[1] = 'z';
+assert( (f & (MEM_Static|MEM_Ephem))==0 );
+}else if( f & MEM_Static ){
+zBuf[1] = 't';
+assert( (f & (MEM_Dyn|MEM_Ephem))==0 );
+}else if( f & MEM_Ephem ){
+zBuf[1] = 'e';
+assert( (f & (MEM_Static|MEM_Dyn))==0 );
+}else{
+zBuf[1] = 's';
+}
+k = 2;
+sqlite3_snprintf(100, &zBuf[k], "%d", pMem->n);
+k += strlen(&zBuf[k]);
+zBuf[k++] = '[';
+for(j=0; j<15 && j<pMem->n; j++){
+u8 c = pMem->z[j];
+if( c>=0x20 && c<0x7f ){
+zBuf[k++] = c;
+}else{
+zBuf[k++] = '.';
+}
+}
+zBuf[k++] = ']';
+sqlite3_snprintf(100,&zBuf[k], encnames[pMem->enc]);
+k += strlen(&zBuf[k]);
+zBuf[k++] = 0;
+}
+}
+#endif
+#ifdef VDBE_PROFILE
+/*
+** The following routine only works on pentium-class processors.
+** It uses the RDTSC opcode to read the cycle count value out of the
+** processor and returns that value.  This can be used for high-res
+** profiling.
+*/
+__inline__ unsigned long long int hwtime(void){
+unsigned long long int x;
+__asm__("rdtsc\n\t"
+"mov %%edx, %%ecx\n\t"
+:"=A" (x));
+return x;
+}
+#endif
+/*
+** The CHECK_FOR_INTERRUPT macro defined here looks to see if the
+** sqlite3_interrupt() routine has been called.  If it has been, then
+** processing of the VDBE program is interrupted.
+**
+** This macro added to every instruction that does a jump in order to
+** implement a loop.  This test used to be on every single instruction,
+** but that meant we more testing that we needed.  By only testing the
+** flag on jump instructions, we get a (small) speed improvement.
+*/
+#define CHECK_FOR_INTERRUPT \
+if( db->u1.isInterrupted ) goto abort_due_to_interrupt;
+/*
+** Execute as much of a VDBE program as we can then return.
+**
+** sqlite3VdbeMakeReady() must be called before this routine in order to
+** close the program with a final OP_Halt and to set up the callbacks
+** and the error message pointer.
+**
+** Whenever a row or result data is available, this routine will either
+** invoke the result callback (if there is one) or return with
+** SQLITE_ROW.
+**
+** If an attempt is made to open a locked database, then this routine
+** will either invoke the busy callback (if there is one) or it will
+** return SQLITE_BUSY.
+**
+** If an error occurs, an error message is written to memory obtained
+** from sqlite3_malloc() and p->zErrMsg is made to point to that memory.
+** The error code is stored in p->rc and this routine returns SQLITE_ERROR.
+**
+** If the callback ever returns non-zero, then the program exits
+** immediately.  There will be no error message but the p->rc field is
+** set to SQLITE_ABORT and this routine will return SQLITE_ERROR.
+**
+** A memory allocation error causes p->rc to be set to SQLITE_NOMEM and this
+** routine to return SQLITE_ERROR.
+**
+** Other fatal errors return SQLITE_ERROR.
+**
+** After this routine has finished, sqlite3VdbeFinalize() should be
+** used to clean up the mess that was left behind.
+*/
+int sqlite3VdbeExec(
+Vdbe *p                    /* The VDBE */
+){
+int pc;                    /* The program counter */
+Op *pOp;                   /* Current operation */
+int rc = SQLITE_OK;        /* Value to return */
+sqlite3 *db = p->db;       /* The database */
+u8 encoding = ENC(db);     /* The database encoding */
+Mem *pTos;                 /* Top entry in the operand stack */
+#ifdef VDBE_PROFILE
+unsigned long long start;  /* CPU clock count at start of opcode */
+int origPc;                /* Program counter at start of opcode */
+#endif
+#ifndef SQLITE_OMIT_PROGRESS_CALLBACK
+int nProgressOps = 0;      /* Opcodes executed since progress callback. */
+#endif
+#ifndef NDEBUG
+Mem *pStackLimit;
+#endif
+if( p->magic!=VDBE_MAGIC_RUN ) return SQLITE_MISUSE;
+assert( db->magic==SQLITE_MAGIC_BUSY );
+pTos = p->pTos;
+sqlite3BtreeMutexArrayEnter(&p->aMutex);
+if( p->rc==SQLITE_NOMEM ){
+/* This happens if a malloc() inside a call to sqlite3_column_text() or
+** sqlite3_column_text16() failed.  */
+goto no_mem;
+}
+assert( p->rc==SQLITE_OK || p->rc==SQLITE_BUSY );
+p->rc = SQLITE_OK;
+assert( p->explain==0 );
+if( p->popStack ){
+popStack(&pTos, p->popStack);
+p->popStack = 0;
+}
+p->resOnStack = 0;
+db->busyHandler.nBusy = 0;
+CHECK_FOR_INTERRUPT;
+sqlite3VdbeIOTraceSql(p);
+#ifdef SQLITE_DEBUG
+if( (p->db->flags & SQLITE_VdbeListing)!=0
+|| sqlite3OsAccess(db->pVfs, "vdbe_explain", SQLITE_ACCESS_EXISTS)
+){
+int i;
+printf("VDBE Program Listing:\n");
+sqlite3VdbePrintSql(p);
+for(i=0; i<p->nOp; i++){
+sqlite3VdbePrintOp(stdout, i, &p->aOp[i]);
+}
+}
+if( sqlite3OsAccess(db->pVfs, "vdbe_trace", SQLITE_ACCESS_EXISTS) ){
+p->trace = stdout;
+}
+#endif
+for(pc=p->pc; rc==SQLITE_OK; pc++){
+assert( pc>=0 && pc<p->nOp );
+assert( pTos<=&p->aStack[pc] );
+if( db->mallocFailed ) goto no_mem;
+#ifdef VDBE_PROFILE
+origPc = pc;
+start = hwtime();
+#endif
+pOp = &p->aOp[pc];
+/* Only allow tracing if SQLITE_DEBUG is defined.
+*/
+#ifdef SQLITE_DEBUG
+if( p->trace ){
+if( pc==0 ){
+printf("VDBE Execution Trace:\n");
+sqlite3VdbePrintSql(p);
+}
+sqlite3VdbePrintOp(p->trace, pc, pOp);
+}
+if( p->trace==0 && pc==0
+&& sqlite3OsAccess(db->pVfs, "vdbe_sqltrace", SQLITE_ACCESS_EXISTS) ){
+sqlite3VdbePrintSql(p);
+}
+#endif
+/* Check to see if we need to simulate an interrupt.  This only happens
+** if we have a special test build.
+*/
+#ifdef SQLITE_TEST
+if( sqlite3_interrupt_count>0 ){
+sqlite3_interrupt_count--;
+if( sqlite3_interrupt_count==0 ){
+sqlite3_interrupt(db);
+}
+}
+#endif
+#ifndef SQLITE_OMIT_PROGRESS_CALLBACK
+/* Call the progress callback if it is configured and the required number
+** of VDBE ops have been executed (either since this invocation of
+** sqlite3VdbeExec() or since last time the progress callback was called).
+** If the progress callback returns non-zero, exit the virtual machine with
+** a return code SQLITE_ABORT.
+*/
+if( db->xProgress ){
+if( db->nProgressOps==nProgressOps ){
+int prc;
+if( sqlite3SafetyOff(db) ) goto abort_due_to_misuse;
+prc =db->xProgress(db->pProgressArg);
+if( sqlite3SafetyOn(db) ) goto abort_due_to_misuse;
+if( prc!=0 ){
+rc = SQLITE_INTERRUPT;
+goto vdbe_halt;
+}
+nProgressOps = 0;
+}
+nProgressOps++;
+}
+#endif
+#ifndef NDEBUG
+/* This is to check that the return value of static function
+** opcodeNoPush() (see vdbeaux.c) returns values that match the
+** implementation of the virtual machine in this file. If
+** opcodeNoPush() returns non-zero, then the stack is guarenteed
+** not to grow when the opcode is executed. If it returns zero, then
+** the stack may grow by at most 1.
+**
+** The global wrapper function sqlite3VdbeOpcodeUsesStack() is not
+** available if NDEBUG is defined at build time.
+*/
+pStackLimit = pTos;
+if( !sqlite3VdbeOpcodeNoPush(pOp->opcode) ){
+pStackLimit++;
+}
+#endif
+switch( pOp->opcode ){
+/*****************************************************************************
+** What follows is a massive switch statement where each case implements a
+** separate instruction in the virtual machine.  If we follow the usual
+** indentation conventions, each case should be indented by 6 spaces.  But
+** that is a lot of wasted space on the left margin.  So the code within
+** the switch statement will break with convention and be flush-left. Another
+** big comment (similar to this one) will mark the point in the code where
+** we transition back to normal indentation.
+**
+** The formatting of each case is important.  The makefile for SQLite
+** generates two C files "opcodes.h" and "opcodes.c" by scanning this
+** file looking for lines that begin with "case OP_".  The opcodes.h files
+** will be filled with #defines that give unique integer values to each
+** opcode and the opcodes.c file is filled with an array of strings where
+** each string is the symbolic name for the corresponding opcode.  If the
+** case statement is followed by a comment of the form "/# same as ... #/"
+** that comment is used to determine the particular value of the opcode.
+**
+** If a comment on the same line as the "case OP_" construction contains
+** the word "no-push", then the opcode is guarenteed not to grow the
+** vdbe stack when it is executed. See function opcode() in
+** vdbeaux.c for details.
+**
+** Documentation about VDBE opcodes is generated by scanning this file
+** for lines of that contain "Opcode:".  That line and all subsequent
+** comment lines are used in the generation of the opcode.html documentation
+** file.
+**
+** SUMMARY:
+**
+**     Formatting is important to scripts that scan this file.
+**     Do not deviate from the formatting style currently in use.
+**
+*****************************************************************************/
+/* Opcode:  Goto * P2 *
+**
+** An unconditional jump to address P2.
+** The next instruction executed will be
+** the one at index P2 from the beginning of
+** the program.
+*/
+case OP_Goto: {             /* no-push */
+CHECK_FOR_INTERRUPT;
+pc = pOp->p2 - 1;
+break;
+}
+/* Opcode:  Gosub * P2 *
+**
+** Push the current address plus 1 onto the return address stack
+** and then jump to address P2.
+**
+** The return address stack is of limited depth.  If too many
+** OP_Gosub operations occur without intervening OP_Returns, then
+** the return address stack will fill up and processing will abort
+** with a fatal error.
+*/
+case OP_Gosub: {            /* no-push */
+assert( p->returnDepth<sizeof(p->returnStack)/sizeof(p->returnStack[0]) );
+p->returnStack[p->returnDepth++] = pc+1;
+pc = pOp->p2 - 1;
+break;
+}
+/* Opcode:  Return * * *
+**
+** Jump immediately to the next instruction after the last unreturned
+** OP_Gosub.  If an OP_Return has occurred for all OP_Gosubs, then
+** processing aborts with a fatal error.
+*/
+case OP_Return: {           /* no-push */
+assert( p->returnDepth>0 );
+p->returnDepth--;
+pc = p->returnStack[p->returnDepth] - 1;
+break;
+}
+/* Opcode:  Halt P1 P2 P3
+**
+** Exit immediately.  All open cursors, Fifos, etc are closed
+** automatically.
+**
+** P1 is the result code returned by sqlite3_exec(), sqlite3_reset(),
+** or sqlite3_finalize().  For a normal halt, this should be SQLITE_OK (0).
+** For errors, it can be some other value.  If P1!=0 then P2 will determine
+** whether or not to rollback the current transaction.  Do not rollback
+** if P2==OE_Fail. Do the rollback if P2==OE_Rollback.  If P2==OE_Abort,
+** then back out all changes that have occurred during this execution of the
+** VDBE, but do not rollback the transaction.
+**
+** If P3 is not null then it is an error message string.
+**
+** There is an implied "Halt 0 0 0" instruction inserted at the very end of
+** every program.  So a jump past the last instruction of the program
+** is the same as executing Halt.
+*/
+case OP_Halt: {            /* no-push */
+p->pTos = pTos;
+p->rc = pOp->p1;
+p->pc = pc;
+p->errorAction = pOp->p2;
+if( pOp->p3 ){
+sqlite3SetString(&p->zErrMsg, pOp->p3, (char*)0);
+}
+rc = sqlite3VdbeHalt(p);
+assert( rc==SQLITE_BUSY || rc==SQLITE_OK );
+if( rc==SQLITE_BUSY ){
+p->rc = rc = SQLITE_BUSY;
+}else{
+rc = p->rc ? SQLITE_ERROR : SQLITE_DONE;
+}
+goto vdbe_return;
+}
+/* Opcode:  StackDepth P1 * *
+**
+** If P1 is less than zero, then store the current stack depth
+** in P1.  If P1 is zero or greater, verify that the current stack
+** depth is equal to P1 and throw an exception if it is not.
+**
+** This opcode is used for internal consistency checking.
+*/
+case OP_StackDepth: {       /* no-push */
+int n = pTos - p->aStack + 1;
+if( pOp->p1<0 ){
+pOp->p1 = n;
+}else if( pOp->p1!=n ){
+p->pTos = pTos;
+p->rc = rc = SQLITE_INTERNAL;
+p->pc = pc;
+p->errorAction = OE_Rollback;
+sqlite3SetString(&p->zErrMsg, "internal error: VDBE stack leak", (char*)0);
+goto vdbe_return;
+}
+break;
+}
+/* Opcode: Integer P1 * *
+**
+** The 32-bit integer value P1 is pushed onto the stack.
+*/
+case OP_Integer: {
+pTos++;
+pTos->flags = MEM_Int;
+pTos->u.i = pOp->p1;
+break;
+}
+/* Opcode: Int64 * * P3
+**
+** P3 is a pointer to a 64-bit integer value.
+** Push  that value onto  the stack.
+*/
+case OP_Int64: {
+pTos++;
+assert( pOp->p3!=0 );
+pTos->flags = MEM_Int;
+memcpy(&pTos->u.i, pOp->p3, 8);
+break;
+}
+/* Opcode: Real * * P3
+**
+** P3 is a pointer to a 64-bit floating point value.  Push that value
+** onto the stack.
+*/
+case OP_Real: {            /* same as TK_FLOAT, */
+pTos++;
+pTos->flags = MEM_Real;
+memcpy(&pTos->r, pOp->p3, 8);
+break;
+}
+/* Opcode: String8 * * P3
+**
+** P3 points to a nul terminated UTF-8 string. This opcode is transformed
+** into an OP_String before it is executed for the first time.
+*/
+case OP_String8: {         /* same as TK_STRING */
+assert( pOp->p3!=0 );
+pOp->opcode = OP_String;
+pOp->p1 = strlen(pOp->p3);
+assert( SQLITE_MAX_SQL_LENGTH <= SQLITE_MAX_LENGTH );
+assert( pOp->p1 <= SQLITE_MAX_LENGTH );
+#ifndef SQLITE_OMIT_UTF16
+if( encoding!=SQLITE_UTF8 ){
+pTos++;
+sqlite3VdbeMemSetStr(pTos, pOp->p3, -1, SQLITE_UTF8, SQLITE_STATIC);
+if( SQLITE_OK!=sqlite3VdbeChangeEncoding(pTos, encoding) ) goto no_mem;
+if( SQLITE_OK!=sqlite3VdbeMemDynamicify(pTos) ) goto no_mem;
+pTos->flags &= ~(MEM_Dyn);
+pTos->flags |= MEM_Static;
+if( pOp->p3type==P3_DYNAMIC ){
+sqlite3_free(pOp->p3);
+}
+pOp->p3type = P3_DYNAMIC;
+pOp->p3 = pTos->z;
+pOp->p1 = pTos->n;
+assert( pOp->p1 <= SQLITE_MAX_LENGTH ); /* Due to SQLITE_MAX_SQL_LENGTH */
+break;
+}
+#endif
+/* Otherwise fall through to the next case, OP_String */
+}
+/* Opcode: String P1 * P3
+**
+** The string value P3 of length P1 (bytes) is pushed onto the stack.
+*/
+case OP_String: {
+assert( pOp->p1 <= SQLITE_MAX_LENGTH ); /* Due to SQLITE_MAX_SQL_LENGTH */
+pTos++;
+assert( pOp->p3!=0 );
+pTos->flags = MEM_Str|MEM_Static|MEM_Term;
+pTos->z = pOp->p3;
+pTos->n = pOp->p1;
+pTos->enc = encoding;
+break;
+}
+/* Opcode: Null * * *
+**
+** Push a NULL onto the stack.
+*/
+case OP_Null: {
+pTos++;
+pTos->flags = MEM_Null;
+pTos->n = 0;
+break;
+}
+#ifndef SQLITE_OMIT_BLOB_LITERAL
+/* Opcode: HexBlob * * P3
+**
+** P3 is an UTF-8 SQL hex encoding of a blob. The blob is pushed onto the
+** vdbe stack.
+**
+** The first time this instruction executes, in transforms itself into a
+** 'Blob' opcode with a binary blob as P3.
+*/
+case OP_HexBlob: {            /* same as TK_BLOB */
+pOp->opcode = OP_Blob;
+pOp->p1 = strlen(pOp->p3)/2;
+assert( SQLITE_MAX_SQL_LENGTH <= SQLITE_MAX_LENGTH );
+assert( pOp->p1 <= SQLITE_MAX_LENGTH );
+if( pOp->p1 ){
+char *zBlob = (char*)sqlite3HexToBlob(db, pOp->p3);
+if( !zBlob ) goto no_mem;
+if( pOp->p3type==P3_DYNAMIC ){
+sqlite3_free(pOp->p3);
+}
+pOp->p3 = zBlob;
+pOp->p3type = P3_DYNAMIC;
+}else{
+if( pOp->p3type==P3_DYNAMIC ){
+sqlite3_free(pOp->p3);
+}
+pOp->p3type = P3_STATIC;
+pOp->p3 = "";
+}
+/* Fall through to the next case, OP_Blob. */
+}
+/* Opcode: Blob P1 * P3
+**
+** P3 points to a blob of data P1 bytes long. Push this
+** value onto the stack. This instruction is not coded directly
+** by the compiler. Instead, the compiler layer specifies
+** an OP_HexBlob opcode, with the hex string representation of
+** the blob as P3. This opcode is transformed to an OP_Blob
+** the first time it is executed.
+*/
+case OP_Blob: {
+pTos++;
+assert( pOp->p1 <= SQLITE_MAX_LENGTH ); /* Due to SQLITE_MAX_SQL_LENGTH */
+sqlite3VdbeMemSetStr(pTos, pOp->p3, pOp->p1, 0, 0);
+pTos->enc = encoding;
+break;
+}
+#endif /* SQLITE_OMIT_BLOB_LITERAL */
+/* Opcode: Variable P1 * *
+**
+** Push the value of variable P1 onto the stack.  A variable is
+** an unknown in the original SQL string as handed to sqlite3_compile().
+** Any occurance of the '?' character in the original SQL is considered
+** a variable.  Variables in the SQL string are number from left to
+** right beginning with 1.  The values of variables are set using the
+** sqlite3_bind() API.
+*/
+case OP_Variable: {
+int j = pOp->p1 - 1;
+Mem *pVar;
+assert( j>=0 && j<p->nVar );
+pVar = &p->aVar[j];
+if( sqlite3VdbeMemTooBig(pVar) ){
+goto too_big;
+}
+pTos++;
+sqlite3VdbeMemShallowCopy(pTos, &p->aVar[j], MEM_Static);
+break;
+}
+/* Opcode: Pop P1 * *
+**
+** P1 elements are popped off of the top of stack and discarded.
+*/
+case OP_Pop: {            /* no-push */
+assert( pOp->p1>=0 );
+popStack(&pTos, pOp->p1);
+assert( pTos>=&p->aStack[-1] );
+break;
+}
+/* Opcode: Dup P1 P2 *
+**
+** A copy of the P1-th element of the stack
+** is made and pushed onto the top of the stack.
+** The top of the stack is element 0.  So the
+** instruction "Dup 0 0 0" will make a copy of the
+** top of the stack.
+**
+** If the content of the P1-th element is a dynamically
+** allocated string, then a new copy of that string
+** is made if P2==0.  If P2!=0, then just a pointer
+** to the string is copied.
+**
+** Also see the Pull instruction.
+*/
+case OP_Dup: {
+Mem *pFrom = &pTos[-pOp->p1];
+assert( pFrom<=pTos && pFrom>=p->aStack );
+pTos++;
+sqlite3VdbeMemShallowCopy(pTos, pFrom, MEM_Ephem);
+if( pOp->p2 ){
+Deephemeralize(pTos);
+}
+break;
+}
+/* Opcode: Pull P1 * *
+**
+** The P1-th element is removed from its current location on
+** the stack and pushed back on top of the stack.  The
+** top of the stack is element 0, so "Pull 0 0 0" is
+** a no-op.  "Pull 1 0 0" swaps the top two elements of
+** the stack.
+**
+** See also the Dup instruction.
+*/
+case OP_Pull: {            /* no-push */
+Mem *pFrom = &pTos[-pOp->p1];
+int i;
+Mem ts;
+ts = *pFrom;
+Deephemeralize(pTos);
+for(i=0; i<pOp->p1; i++, pFrom++){
+Deephemeralize(&pFrom[1]);
+assert( (pFrom[1].flags & MEM_Ephem)==0 );
+*pFrom = pFrom[1];
+if( pFrom->flags & MEM_Short ){
+assert( pFrom->flags & (MEM_Str|MEM_Blob) );
+assert( pFrom->z==pFrom[1].zShort );
+pFrom->z = pFrom->zShort;
+}
+}
+*pTos = ts;
+if( pTos->flags & MEM_Short ){
+assert( pTos->flags & (MEM_Str|MEM_Blob) );
+assert( pTos->z==pTos[-pOp->p1].zShort );
+pTos->z = pTos->zShort;
+}
+break;
+}
+/* Opcode: Push P1 * *
+**
+** Overwrite the value of the P1-th element down on the
+** stack (P1==0 is the top of the stack) with the value
+** of the top of the stack.  Then pop the top of the stack.
+*/
+case OP_Push: {            /* no-push */
+Mem *pTo = &pTos[-pOp->p1];
+assert( pTo>=p->aStack );
+sqlite3VdbeMemMove(pTo, pTos);
+pTos--;
+break;
+}
+/* Opcode: Callback P1 * *
+**
+** The top P1 values on the stack represent a single result row from
+** a query.  This opcode causes the sqlite3_step() call to terminate
+** with an SQLITE_ROW return code and it sets up the sqlite3_stmt
+** structure to provide access to the top P1 values as the result
+** row.  When the sqlite3_step() function is run again, the top P1
+** values will be automatically popped from the stack before the next
+** instruction executes.
+*/
+case OP_Callback: {            /* no-push */
+Mem *pMem;
+Mem *pFirstColumn;
+assert( p->nResColumn==pOp->p1 );
+/* Data in the pager might be moved or changed out from under us
+** in between the return from this sqlite3_step() call and the
+** next call to sqlite3_step().  So deephermeralize everything on
+** the stack.  Note that ephemeral data is never stored in memory
+** cells so we do not have to worry about them.
+*/
+pFirstColumn = &pTos[0-pOp->p1];
+for(pMem = p->aStack; pMem<pFirstColumn; pMem++){
+Deephemeralize(pMem);
+}
+/* Invalidate all ephemeral cursor row caches */
+p->cacheCtr = (p->cacheCtr + 2)|1;
+/* Make sure the results of the current row are \000 terminated
+** and have an assigned type.  The results are deephemeralized as
+** as side effect.
+*/
+for(; pMem<=pTos; pMem++ ){
+sqlite3VdbeMemNulTerminate(pMem);
+storeTypeInfo(pMem, encoding);
+}
+/* Set up the statement structure so that it will pop the current
+** results from the stack when the statement returns.
+*/
+p->resOnStack = 1;
+p->nCallback++;
+p->popStack = pOp->p1;
+p->pc = pc + 1;
+p->pTos = pTos;
+rc = SQLITE_ROW;
+goto vdbe_return;
+}
+/* Opcode: Concat P1 P2 *
+**
+** Look at the first P1+2 elements of the stack.  Append them all
+** together with the lowest element first.  The original P1+2 elements
+** are popped from the stack if P2==0 and retained if P2==1.  If
+** any element of the stack is NULL, then the result is NULL.
+**
+** When P1==1, this routine makes a copy of the top stack element
+** into memory obtained from sqlite3_malloc().
+*/
+case OP_Concat: {           /* same as TK_CONCAT */
+char *zNew;
+i64 nByte;
+int nField;
+int i, j;
+Mem *pTerm;
+/* Loop through the stack elements to see how long the result will be. */
+nField = pOp->p1 + 2;
+pTerm = &pTos[1-nField];
+nByte = 0;
+for(i=0; i<nField; i++, pTerm++){
+assert( pOp->p2==0 || (pTerm->flags&MEM_Str) );
+if( pTerm->flags&MEM_Null ){
+nByte = -1;
+break;
+}
+ExpandBlob(pTerm);
+Stringify(pTerm, encoding);
+nByte += pTerm->n;
+}
+if( nByte<0 ){
+/* If nByte is less than zero, then there is a NULL value on the stack.
+** In this case just pop the values off the stack (if required) and
+** push on a NULL.
+*/
+if( pOp->p2==0 ){
+popStack(&pTos, nField);
+}
+pTos++;
+pTos->flags = MEM_Null;
+}else{
+/* Otherwise malloc() space for the result and concatenate all the
+** stack values.
+*/
+if( nByte+2>SQLITE_MAX_LENGTH ){
+goto too_big;
+}
+zNew = (char*)sqlite3DbMallocRaw(db, nByte+2 );
+if( zNew==0 ) goto no_mem;
+j = 0;
+pTerm = &pTos[1-nField];
+for(i=j=0; i<nField; i++, pTerm++){
+int n = pTerm->n;
+assert( pTerm->flags & (MEM_Str|MEM_Blob) );
+memcpy(&zNew[j], pTerm->z, n);
+j += n;
+}
+zNew[j] = 0;
+zNew[j+1] = 0;
+assert( j==nByte );
+if( pOp->p2==0 ){
+popStack(&pTos, nField);
+}
+pTos++;
+pTos->n = j;
+pTos->flags = MEM_Str|MEM_Dyn|MEM_Term;
+pTos->xDel = 0;
+pTos->enc = encoding;
+pTos->z = zNew;
+}
+break;
+}
+/* Opcode: Add * * *
+**
+** Pop the top two elements from the stack, add them together,
+** and push the result back onto the stack.  If either element
+** is a string then it is converted to a double using the atof()
+** function before the addition.
+** If either operand is NULL, the result is NULL.
+*/
+/* Opcode: Multiply * * *
+**
+** Pop the top two elements from the stack, multiply them together,
+** and push the result back onto the stack.  If either element
+** is a string then it is converted to a double using the atof()
+** function before the multiplication.
+** If either operand is NULL, the result is NULL.
+*/
+/* Opcode: Subtract * * *
+**
+** Pop the top two elements from the stack, subtract the
+** first (what was on top of the stack) from the second (the
+** next on stack)
+** and push the result back onto the stack.  If either element
+** is a string then it is converted to a double using the atof()
+** function before the subtraction.
+** If either operand is NULL, the result is NULL.
+*/
+/* Opcode: Divide * * *
+**
+** Pop the top two elements from the stack, divide the
+** first (what was on top of the stack) from the second (the
+** next on stack)
+** and push the result back onto the stack.  If either element
+** is a string then it is converted to a double using the atof()
+** function before the division.  Division by zero returns NULL.
+** If either operand is NULL, the result is NULL.
+*/
+/* Opcode: Remainder * * *
+**
+** Pop the top two elements from the stack, divide the
+** first (what was on top of the stack) from the second (the
+** next on stack)
+** and push the remainder after division onto the stack.  If either element
+** is a string then it is converted to a double using the atof()
+** function before the division.  Division by zero returns NULL.
+** If either operand is NULL, the result is NULL.
+*/
+case OP_Add:                   /* same as TK_PLUS, no-push */
+case OP_Subtract:              /* same as TK_MINUS, no-push */
+case OP_Multiply:              /* same as TK_STAR, no-push */
+case OP_Divide:                /* same as TK_SLASH, no-push */
+case OP_Remainder: {           /* same as TK_REM, no-push */
+Mem *pNos = &pTos[-1];
+int flags;
+assert( pNos>=p->aStack );
+flags = pTos->flags | pNos->flags;
+if( (flags & MEM_Null)!=0 ){
+Release(pTos);
+pTos--;
+Release(pTos);
+pTos->flags = MEM_Null;
+}else if( (pTos->flags & pNos->flags & MEM_Int)==MEM_Int ){
+i64 a, b;
+a = pTos->u.i;
+b = pNos->u.i;
+switch( pOp->opcode ){
+case OP_Add:         b += a;       break;
+case OP_Subtract:    b -= a;       break;
+case OP_Multiply:    b *= a;       break;
+case OP_Divide: {
+if( a==0 ) goto divide_by_zero;
+/* Dividing the largest possible negative 64-bit integer (1<<63) by
+** -1 returns an integer to large to store in a 64-bit data-type. On
+** some architectures, the value overflows to (1<<63). On others,
+** a SIGFPE is issued. The following statement normalizes this
+** behaviour so that all architectures behave as if integer
+** overflow occured.
+*/
+if( a==-1 && b==(((i64)1)<<63) ) a = 1;
+b /= a;
+break;
+}
+default: {
+if( a==0 ) goto divide_by_zero;
+if( a==-1 ) a = 1;
+b %= a;
+break;
+}
+}
+Release(pTos);
+pTos--;
+Release(pTos);
+pTos->u.i = b;
+pTos->flags = MEM_Int;
+}else{
+double a, b;
+a = sqlite3VdbeRealValue(pTos);
+b = sqlite3VdbeRealValue(pNos);
+switch( pOp->opcode ){
+case OP_Add:         b += a;       break;
+case OP_Subtract:    b -= a;       break;
+case OP_Multiply:    b *= a;       break;
+case OP_Divide: {
+if( a==0.0 ) goto divide_by_zero;
+b /= a;
+break;
+}
+default: {
+i64 ia = (i64)a;
+i64 ib = (i64)b;
+if( ia==0 ) goto divide_by_zero;
+if( ia==-1 ) ia = 1;
+b = ib % ia;
+break;
+}
+}
+if( sqlite3_isnan(b) ){
+goto divide_by_zero;
+}
+Release(pTos);
+pTos--;
+Release(pTos);
+pTos->r = b;
+pTos->flags = MEM_Real;
+if( (flags & MEM_Real)==0 ){
+sqlite3VdbeIntegerAffinity(pTos);
+}
+}
+break;
+divide_by_zero:
+Release(pTos);
+pTos--;
+Release(pTos);
+pTos->flags = MEM_Null;
+break;
+}
+/* Opcode: CollSeq * * P3
+**
+** P3 is a pointer to a CollSeq struct. If the next call to a user function
+** or aggregate calls sqlite3GetFuncCollSeq(), this collation sequence will
+** be returned. This is used by the built-in min(), max() and nullif()
+** functions.
+**
+** The interface used by the implementation of the aforementioned functions
+** to retrieve the collation sequence set by this opcode is not available
+** publicly, only to user functions defined in func.c.
+*/
+case OP_CollSeq: {             /* no-push */
+assert( pOp->p3type==P3_COLLSEQ );
+break;
+}
+/* Opcode: Function P1 P2 P3
+**
+** Invoke a user function (P3 is a pointer to a Function structure that
+** defines the function) with P2 arguments taken from the stack.  Pop all
+** arguments from the stack and push back the result.
+**
+** P1 is a 32-bit bitmask indicating whether or not each argument to the
+** function was determined to be constant at compile time. If the first
+** argument was constant then bit 0 of P1 is set. This is used to determine
+** whether meta data associated with a user function argument using the
+** sqlite3_set_auxdata() API may be safely retained until the next
+** invocation of this opcode.
+**
+** See also: AggStep and AggFinal
+*/
+case OP_Function: {
+int i;
+Mem *pArg;
+sqlite3_context ctx;
+sqlite3_value **apVal;
+int n = pOp->p2;
+apVal = p->apArg;
+assert( apVal || n==0 );
+pArg = &pTos[1-n];
+for(i=0; i<n; i++, pArg++){
+apVal[i] = pArg;
+storeTypeInfo(pArg, encoding);
+}
+assert( pOp->p3type==P3_FUNCDEF || pOp->p3type==P3_VDBEFUNC );
+if( pOp->p3type==P3_FUNCDEF ){
+ctx.pFunc = (FuncDef*)pOp->p3;
+ctx.pVdbeFunc = 0;
+}else{
+ctx.pVdbeFunc = (VdbeFunc*)pOp->p3;
+ctx.pFunc = ctx.pVdbeFunc->pFunc;
+}
+ctx.s.flags = MEM_Null;
+ctx.s.z = 0;
+ctx.s.xDel = 0;
+ctx.s.db = db;
+ctx.isError = 0;
+if( ctx.pFunc->needCollSeq ){
+assert( pOp>p->aOp );
+assert( pOp[-1].p3type==P3_COLLSEQ );
+assert( pOp[-1].opcode==OP_CollSeq );
+ctx.pColl = (CollSeq *)pOp[-1].p3;
+}
+if( sqlite3SafetyOff(db) ) goto abort_due_to_misuse;
+(*ctx.pFunc->xFunc)(&ctx, n, apVal);
+if( sqlite3SafetyOn(db) ) goto abort_due_to_misuse;
+if( db->mallocFailed ){
+/* Even though a malloc() has failed, the implementation of the
+** user function may have called an sqlite3_result_XXX() function
+** to return a value. The following call releases any resources
+** associated with such a value.
+**
+** Note: Maybe MemRelease() should be called if sqlite3SafetyOn()
+** fails also (the if(...) statement above). But if people are
+** misusing sqlite, they have bigger problems than a leaked value.
+*/
+sqlite3VdbeMemRelease(&ctx.s);
+goto no_mem;
+}
+popStack(&pTos, n);
+/* If any auxilary data functions have been called by this user function,
+** immediately call the destructor for any non-static values.
+*/
+if( ctx.pVdbeFunc ){
+sqlite3VdbeDeleteAuxData(ctx.pVdbeFunc, pOp->p1);
+pOp->p3 = (char *)ctx.pVdbeFunc;
+pOp->p3type = P3_VDBEFUNC;
+}
+/* If the function returned an error, throw an exception */
+if( ctx.isError ){
+sqlite3SetString(&p->zErrMsg, sqlite3_value_text(&ctx.s), (char*)0);
+rc = SQLITE_ERROR;
+}
+/* Copy the result of the function to the top of the stack */
+sqlite3VdbeChangeEncoding(&ctx.s, encoding);
+pTos++;
+pTos->flags = 0;
+sqlite3VdbeMemMove(pTos, &ctx.s);
+if( sqlite3VdbeMemTooBig(pTos) ){
+goto too_big;
+}
+break;
+}
+/* Opcode: BitAnd * * *
+**
+** Pop the top two elements from the stack.  Convert both elements
+** to integers.  Push back onto the stack the bit-wise AND of the
+** two elements.
+** If either operand is NULL, the result is NULL.
+*/
+/* Opcode: BitOr * * *
+**
+** Pop the top two elements from the stack.  Convert both elements
+** to integers.  Push back onto the stack the bit-wise OR of the
+** two elements.
+** If either operand is NULL, the result is NULL.
+*/
+/* Opcode: ShiftLeft * * *
+**
+** Pop the top two elements from the stack.  Convert both elements
+** to integers.  Push back onto the stack the second element shifted
+** left by N bits where N is the top element on the stack.
+** If either operand is NULL, the result is NULL.
+*/
+/* Opcode: ShiftRight * * *
+**
+** Pop the top two elements from the stack.  Convert both elements
+** to integers.  Push back onto the stack the second element shifted
+** right by N bits where N is the top element on the stack.
+** If either operand is NULL, the result is NULL.
+*/
+case OP_BitAnd:                 /* same as TK_BITAND, no-push */
+case OP_BitOr:                  /* same as TK_BITOR, no-push */
+case OP_ShiftLeft:              /* same as TK_LSHIFT, no-push */
+case OP_ShiftRight: {           /* same as TK_RSHIFT, no-push */
+Mem *pNos = &pTos[-1];
+i64 a, b;
+assert( pNos>=p->aStack );
+if( (pTos->flags | pNos->flags) & MEM_Null ){
+popStack(&pTos, 2);
+pTos++;
+pTos->flags = MEM_Null;
+break;
+}
+a = sqlite3VdbeIntValue(pNos);
+b = sqlite3VdbeIntValue(pTos);
+switch( pOp->opcode ){
+case OP_BitAnd:      a &= b;     break;
+case OP_BitOr:       a |= b;     break;
+case OP_ShiftLeft:   a <<= b;    break;
+case OP_ShiftRight:  a >>= b;    break;
+default:   /* CANT HAPPEN */     break;
+}
+Release(pTos);
+pTos--;
+Release(pTos);
+pTos->u.i = a;
+pTos->flags = MEM_Int;
+break;
+}
+/* Opcode: AddImm  P1 * *
+**
+** Add the value P1 to whatever is on top of the stack.  The result
+** is always an integer.
+**
+** To force the top of the stack to be an integer, just add 0.
+*/
+case OP_AddImm: {            /* no-push */
+assert( pTos>=p->aStack );
+sqlite3VdbeMemIntegerify(pTos);
+pTos->u.i += pOp->p1;
+break;
+}
+/* Opcode: ForceInt P1 P2 *
+**
+** Convert the top of the stack into an integer.  If the current top of
+** the stack is not numeric (meaning that is is a NULL or a string that
+** does not look like an integer or floating point number) then pop the
+** stack and jump to P2.  If the top of the stack is numeric then
+** convert it into the least integer that is greater than or equal to its
+** current value if P1==0, or to the least integer that is strictly
+** greater than its current value if P1==1.
+*/
+case OP_ForceInt: {            /* no-push */
+i64 v;
+assert( pTos>=p->aStack );
+applyAffinity(pTos, SQLITE_AFF_NUMERIC, encoding);
+if( (pTos->flags & (MEM_Int|MEM_Real))==0 ){
+Release(pTos);
+pTos--;
+pc = pOp->p2 - 1;
+break;
+}
+if( pTos->flags & MEM_Int ){
+v = pTos->u.i + (pOp->p1!=0);
+}else{
+/* FIX ME:  should this not be assert( pTos->flags & MEM_Real ) ??? */
+sqlite3VdbeMemRealify(pTos);
+v = (int)pTos->r;
+if( pTos->r>(double)v ) v++;
+if( pOp->p1 && pTos->r==(double)v ) v++;
+}
+Release(pTos);
+pTos->u.i = v;
+pTos->flags = MEM_Int;
+break;
+}
+/* Opcode: MustBeInt P1 P2 *
+**
+** Force the top of the stack to be an integer.  If the top of the
+** stack is not an integer and cannot be converted into an integer
+** without data loss, then jump immediately to P2, or if P2==0
+** raise an SQLITE_MISMATCH exception.
+**
+** If the top of the stack is not an integer and P2 is not zero and
+** P1 is 1, then the stack is popped.  In all other cases, the depth
+** of the stack is unchanged.
+*/
+case OP_MustBeInt: {            /* no-push */
+assert( pTos>=p->aStack );
+applyAffinity(pTos, SQLITE_AFF_NUMERIC, encoding);
+if( (pTos->flags & MEM_Int)==0 ){
+if( pOp->p2==0 ){
+rc = SQLITE_MISMATCH;
+goto abort_due_to_error;
+}else{
+if( pOp->p1 ) popStack(&pTos, 1);
+pc = pOp->p2 - 1;
+}
+}else{
+Release(pTos);
+pTos->flags = MEM_Int;
+}
+break;
+}
+/* Opcode: RealAffinity * * *
+**
+** If the top of the stack is an integer, convert it to a real value.
+**
+** This opcode is used when extracting information from a column that
+** has REAL affinity.  Such column values may still be stored as
+** integers, for space efficiency, but after extraction we want them
+** to have only a real value.
+*/
+case OP_RealAffinity: {                  /* no-push */
+assert( pTos>=p->aStack );
+if( pTos->flags & MEM_Int ){
+sqlite3VdbeMemRealify(pTos);
+}
+break;
+}
+#ifndef SQLITE_OMIT_CAST
+/* Opcode: ToText * * *
+**
+** Force the value on the top of the stack to be text.
+** If the value is numeric, convert it to a string using the
+** equivalent of printf().  Blob values are unchanged and
+** are afterwards simply interpreted as text.
+**
+** A NULL value is not changed by this routine.  It remains NULL.
+*/
+case OP_ToText: {                  /* same as TK_TO_TEXT, no-push */
+assert( pTos>=p->aStack );
+if( pTos->flags & MEM_Null ) break;
+assert( MEM_Str==(MEM_Blob>>3) );
+pTos->flags |= (pTos->flags&MEM_Blob)>>3;
+applyAffinity(pTos, SQLITE_AFF_TEXT, encoding);
+rc = ExpandBlob(pTos);
+assert( pTos->flags & MEM_Str );
+pTos->flags &= ~(MEM_Int|MEM_Real|MEM_Blob);
+break;
+}
+/* Opcode: ToBlob * * *
+**
+** Force the value on the top of the stack to be a BLOB.
+** If the value is numeric, convert it to a string first.
+** Strings are simply reinterpreted as blobs with no change
+** to the underlying data.
+**
+** A NULL value is not changed by this routine.  It remains NULL.
+*/
+case OP_ToBlob: {                  /* same as TK_TO_BLOB, no-push */
+assert( pTos>=p->aStack );
+if( pTos->flags & MEM_Null ) break;
+if( (pTos->flags & MEM_Blob)==0 ){
+applyAffinity(pTos, SQLITE_AFF_TEXT, encoding);
+assert( pTos->flags & MEM_Str );
+pTos->flags |= MEM_Blob;
+}
+pTos->flags &= ~(MEM_Int|MEM_Real|MEM_Str);
+break;
+}
+/* Opcode: ToNumeric * * *
+**
+** Force the value on the top of the stack to be numeric (either an
+** integer or a floating-point number.)
+** If the value is text or blob, try to convert it to an using the
+** equivalent of atoi() or atof() and store 0 if no such conversion
+** is possible.
+**
+** A NULL value is not changed by this routine.  It remains NULL.
+*/
+case OP_ToNumeric: {                  /* same as TK_TO_NUMERIC, no-push */
+assert( pTos>=p->aStack );
+if( (pTos->flags & (MEM_Null|MEM_Int|MEM_Real))==0 ){
+sqlite3VdbeMemNumerify(pTos);
+}
+break;
+}
+#endif /* SQLITE_OMIT_CAST */
+/* Opcode: ToInt * * *
+**
+** Force the value on the top of the stack to be an integer.  If
+** The value is currently a real number, drop its fractional part.
+** If the value is text or blob, try to convert it to an integer using the
+** equivalent of atoi() and store 0 if no such conversion is possible.
+**
+** A NULL value is not changed by this routine.  It remains NULL.
+*/
+case OP_ToInt: {                  /* same as TK_TO_INT, no-push */
+assert( pTos>=p->aStack );
+if( (pTos->flags & MEM_Null)==0 ){
+sqlite3VdbeMemIntegerify(pTos);
+}
+break;
+}
+#ifndef SQLITE_OMIT_CAST
+/* Opcode: ToReal * * *
+**
+** Force the value on the top of the stack to be a floating point number.
+** If The value is currently an integer, convert it.
+** If the value is text or blob, try to convert it to an integer using the
+** equivalent of atoi() and store 0 if no such conversion is possible.
+**
+** A NULL value is not changed by this routine.  It remains NULL.
+*/
+case OP_ToReal: {                  /* same as TK_TO_REAL, no-push */
+assert( pTos>=p->aStack );
+if( (pTos->flags & MEM_Null)==0 ){
+sqlite3VdbeMemRealify(pTos);
+}
+break;
+}
+#endif /* SQLITE_OMIT_CAST */
+/* Opcode: Eq P1 P2 P3
+**
+** Pop the top two elements from the stack.  If they are equal, then
+** jump to instruction P2.  Otherwise, continue to the next instruction.
+**
+** If the 0x100 bit of P1 is true and either operand is NULL then take the
+** jump.  If the 0x100 bit of P1 is clear then fall thru if either operand
+** is NULL.
+**
+** If the 0x200 bit of P1 is set and either operand is NULL then
+** both operands are converted to integers prior to comparison.
+** NULL operands are converted to zero and non-NULL operands are
+** converted to 1.  Thus, for example, with 0x200 set,  NULL==NULL is true
+** whereas it would normally be NULL.  Similarly,  NULL==123 is false when
+** 0x200 is set but is NULL when the 0x200 bit of P1 is clear.
+**
+** The least significant byte of P1 (mask 0xff) must be an affinity character -
+** SQLITE_AFF_TEXT, SQLITE_AFF_INTEGER, and so forth. An attempt is made
+** to coerce both values
+** according to the affinity before the comparison is made. If the byte is
+** 0x00, then numeric affinity is used.
+**
+** Once any conversions have taken place, and neither value is NULL,
+** the values are compared. If both values are blobs, or both are text,
+** then memcmp() is used to determine the results of the comparison. If
+** both values are numeric, then a numeric comparison is used. If the
+** two values are of different types, then they are inequal.
+**
+** If P2 is zero, do not jump.  Instead, push an integer 1 onto the
+** stack if the jump would have been taken, or a 0 if not.  Push a
+** NULL if either operand was NULL.
+**
+** If P3 is not NULL it is a pointer to a collating sequence (a CollSeq
+** structure) that defines how to compare text.
+*/
+/* Opcode: Ne P1 P2 P3
+**
+** This works just like the Eq opcode except that the jump is taken if
+** the operands from the stack are not equal.  See the Eq opcode for
+** additional information.
+*/
+/* Opcode: Lt P1 P2 P3
+**
+** This works just like the Eq opcode except that the jump is taken if
+** the 2nd element down on the stack is less than the top of the stack.
+** See the Eq opcode for additional information.
+*/
+/* Opcode: Le P1 P2 P3
+**
+** This works just like the Eq opcode except that the jump is taken if
+** the 2nd element down on the stack is less than or equal to the
+** top of the stack.  See the Eq opcode for additional information.
+*/
+/* Opcode: Gt P1 P2 P3
+**
+** This works just like the Eq opcode except that the jump is taken if
+** the 2nd element down on the stack is greater than the top of the stack.
+** See the Eq opcode for additional information.
+*/
+/* Opcode: Ge P1 P2 P3
+**
+** This works just like the Eq opcode except that the jump is taken if
+** the 2nd element down on the stack is greater than or equal to the
+** top of the stack.  See the Eq opcode for additional information.
+*/
+case OP_Eq:               /* same as TK_EQ, no-push */
+case OP_Ne:               /* same as TK_NE, no-push */
+case OP_Lt:               /* same as TK_LT, no-push */
+case OP_Le:               /* same as TK_LE, no-push */
+case OP_Gt:               /* same as TK_GT, no-push */
+case OP_Ge: {             /* same as TK_GE, no-push */
+Mem *pNos;
+int flags;
+int res;
+char affinity;
+pNos = &pTos[-1];
+flags = pTos->flags|pNos->flags;
+/* If either value is a NULL P2 is not zero, take the jump if the least
+** significant byte of P1 is true. If P2 is zero, then push a NULL onto
+** the stack.
+*/
+if( flags&MEM_Null ){
+if( (pOp->p1 & 0x200)!=0 ){
+/* The 0x200 bit of P1 means, roughly "do not treat NULL as the
+** magic SQL value it normally is - treat it as if it were another
+** integer".
+**
+** With 0x200 set, if either operand is NULL then both operands
+** are converted to integers prior to being passed down into the
+** normal comparison logic below.  NULL operands are converted to
+** zero and non-NULL operands are converted to 1.  Thus, for example,
+** with 0x200 set,  NULL==NULL is true whereas it would normally
+** be NULL.  Similarly,  NULL!=123 is true.
+*/
+sqlite3VdbeMemSetInt64(pTos, (pTos->flags & MEM_Null)==0);
+sqlite3VdbeMemSetInt64(pNos, (pNos->flags & MEM_Null)==0);
+}else{
+/* If the 0x200 bit of P1 is clear and either operand is NULL then
+** the result is always NULL.  The jump is taken if the 0x100 bit
+** of P1 is set.
+*/
+popStack(&pTos, 2);
+if( pOp->p2 ){
+if( pOp->p1 & 0x100 ){
+pc = pOp->p2-1;
+}
+}else{
+pTos++;
+pTos->flags = MEM_Null;
+}
+break;
+}
+}
+affinity = pOp->p1 & 0xFF;
+if( affinity ){
+applyAffinity(pNos, affinity, encoding);
+applyAffinity(pTos, affinity, encoding);
+}
+assert( pOp->p3type==P3_COLLSEQ || pOp->p3==0 );
+ExpandBlob(pNos);
+ExpandBlob(pTos);
+res = sqlite3MemCompare(pNos, pTos, (CollSeq*)pOp->p3);
+switch( pOp->opcode ){
+case OP_Eq:    res = res==0;     break;
+case OP_Ne:    res = res!=0;     break;
+case OP_Lt:    res = res<0;      break;
+case OP_Le:    res = res<=0;     break;
+case OP_Gt:    res = res>0;      break;
+default:       res = res>=0;     break;
+}
+popStack(&pTos, 2);
+if( pOp->p2 ){
+if( res ){
+pc = pOp->p2-1;
+}
+}else{
+pTos++;
+pTos->flags = MEM_Int;
+pTos->u.i = res;
+}
+break;
+}
+/* Opcode: And * * *
+**
+** Pop two values off the stack.  Take the logical AND of the
+** two values and push the resulting boolean value back onto the
+** stack.
+*/
+/* Opcode: Or * * *
+**
+** Pop two values off the stack.  Take the logical OR of the
+** two values and push the resulting boolean value back onto the
+** stack.
+*/
+case OP_And:              /* same as TK_AND, no-push */
+case OP_Or: {             /* same as TK_OR, no-push */
+Mem *pNos = &pTos[-1];
+int v1, v2;    /* 0==TRUE, 1==FALSE, 2==UNKNOWN or NULL */
+assert( pNos>=p->aStack );
+if( pTos->flags & MEM_Null ){
+v1 = 2;
+}else{
+sqlite3VdbeMemIntegerify(pTos);
+v1 = pTos->u.i==0;
+}
+if( pNos->flags & MEM_Null ){
+v2 = 2;
+}else{
+sqlite3VdbeMemIntegerify(pNos);
+v2 = pNos->u.i==0;
+}
+if( pOp->opcode==OP_And ){
+static const unsigned char and_logic[] = { 0, 1, 2, 1, 1, 1, 2, 1, 2 };
+v1 = and_logic[v1*3+v2];
+}else{
+static const unsigned char or_logic[] = { 0, 0, 0, 0, 1, 2, 0, 2, 2 };
+v1 = or_logic[v1*3+v2];
+}
+popStack(&pTos, 2);
+pTos++;
+if( v1==2 ){
+pTos->flags = MEM_Null;
+}else{
+pTos->u.i = v1==0;
+pTos->flags = MEM_Int;
+}
+break;
+}
+/* Opcode: Negative * * *
+**
+** Treat the top of the stack as a numeric quantity.  Replace it
+** with its additive inverse.  If the top of the stack is NULL
+** its value is unchanged.
+*/
+/* Opcode: AbsValue * * *
+**
+** Treat the top of the stack as a numeric quantity.  Replace it
+** with its absolute value. If the top of the stack is NULL
+** its value is unchanged.
+*/
+case OP_Negative:              /* same as TK_UMINUS, no-push */
+case OP_AbsValue: {
+assert( pTos>=p->aStack );
+if( (pTos->flags & (MEM_Real|MEM_Int|MEM_Null))==0 ){
+sqlite3VdbeMemNumerify(pTos);
+}
+if( pTos->flags & MEM_Real ){
+Release(pTos);
+if( pOp->opcode==OP_Negative || pTos->r<0.0 ){
+pTos->r = -pTos->r;
+}
+pTos->flags = MEM_Real;
+}else if( pTos->flags & MEM_Int ){
+Release(pTos);
+if( pOp->opcode==OP_Negative || pTos->u.i<0 ){
+pTos->u.i = -pTos->u.i;
+}
+pTos->flags = MEM_Int;
+}
+break;
+}
+/* Opcode: Not * * *
+**
+** Interpret the top of the stack as a boolean value.  Replace it
+** with its complement.  If the top of the stack is NULL its value
+** is unchanged.
+*/
+case OP_Not: {                /* same as TK_NOT, no-push */
+assert( pTos>=p->aStack );
+if( pTos->flags & MEM_Null ) break;  /* Do nothing to NULLs */
+sqlite3VdbeMemIntegerify(pTos);
+assert( (pTos->flags & MEM_Dyn)==0 );
+pTos->u.i = !pTos->u.i;
+pTos->flags = MEM_Int;
+break;
+}
+/* Opcode: BitNot * * *
+**
+** Interpret the top of the stack as an value.  Replace it
+** with its ones-complement.  If the top of the stack is NULL its
+** value is unchanged.
+*/
+case OP_BitNot: {             /* same as TK_BITNOT, no-push */
+assert( pTos>=p->aStack );
+if( pTos->flags & MEM_Null ) break;  /* Do nothing to NULLs */
+sqlite3VdbeMemIntegerify(pTos);
+assert( (pTos->flags & MEM_Dyn)==0 );
+pTos->u.i = ~pTos->u.i;
+pTos->flags = MEM_Int;
+break;
+}
+/* Opcode: Noop * * *
+**
+** Do nothing.  This instruction is often useful as a jump
+** destination.
+*/
+/*
+** The magic Explain opcode are only inserted when explain==2 (which
+** is to say when the EXPLAIN QUERY PLAN syntax is used.)
+** This opcode records information from the optimizer.  It is the
+** the same as a no-op.  This opcodesnever appears in a real VM program.
+*/
+case OP_Explain:
+case OP_Noop: {            /* no-push */
+break;
+}
+/* Opcode: If P1 P2 *
+**
+** Pop a single boolean from the stack.  If the boolean popped is
+** true, then jump to p2.  Otherwise continue to the next instruction.
+** An integer is false if zero and true otherwise.  A string is
+** false if it has zero length and true otherwise.
+**
+** If the value popped of the stack is NULL, then take the jump if P1
+** is true and fall through if P1 is false.
+*/
+/* Opcode: IfNot P1 P2 *
+**
+** Pop a single boolean from the stack.  If the boolean popped is
+** false, then jump to p2.  Otherwise continue to the next instruction.
+** An integer is false if zero and true otherwise.  A string is
+** false if it has zero length and true otherwise.
+**
+** If the value popped of the stack is NULL, then take the jump if P1
+** is true and fall through if P1 is false.
+*/
+case OP_If:                 /* no-push */
+case OP_IfNot: {            /* no-push */
+int c;
+assert( pTos>=p->aStack );
+if( pTos->flags & MEM_Null ){
+c = pOp->p1;
+}else{
+#ifdef SQLITE_OMIT_FLOATING_POINT
+c = sqlite3VdbeIntValue(pTos);
+#else
+c = sqlite3VdbeRealValue(pTos)!=0.0;
+#endif
+if( pOp->opcode==OP_IfNot ) c = !c;
+}
+Release(pTos);
+pTos--;
+if( c ) pc = pOp->p2-1;
+break;
+}
+/* Opcode: IsNull P1 P2 *
+**
+** Check the top of the stack and jump to P2 if the top of the stack
+** is NULL.  If P1 is positive, then pop P1 elements from the stack
+** regardless of whether or not the jump is taken.  If P1 is negative,
+** pop -P1 elements from the stack only if the jump is taken and leave
+** the stack unchanged if the jump is not taken.
+*/
+case OP_IsNull: {            /* same as TK_ISNULL, no-push */
+if( pTos->flags & MEM_Null ){
+pc = pOp->p2-1;
+if( pOp->p1<0 ){
+popStack(&pTos, -pOp->p1);
+}
+}
+if( pOp->p1>0 ){
+popStack(&pTos, pOp->p1);
+}
+break;
+}
+/* Opcode: NotNull P1 P2 *
+**
+** Jump to P2 if the top abs(P1) values on the stack are all not NULL.
+** Regardless of whether or not the jump is taken, pop the stack
+** P1 times if P1 is greater than zero.  But if P1 is negative,
+** leave the stack unchanged.
+*/
+case OP_NotNull: {            /* same as TK_NOTNULL, no-push */
+int i, cnt;
+cnt = pOp->p1;
+if( cnt<0 ) cnt = -cnt;
+assert( &pTos[1-cnt] >= p->aStack );
+for(i=0; i<cnt && (pTos[1+i-cnt].flags & MEM_Null)==0; i++){}
+if( i>=cnt ) pc = pOp->p2-1;
+if( pOp->p1>0 ) popStack(&pTos, cnt);
+break;
+}
+/* Opcode: SetNumColumns P1 P2 *
+**
+** Before the OP_Column opcode can be executed on a cursor, this
+** opcode must be called to set the number of fields in the table.
+**
+** This opcode sets the number of columns for cursor P1 to P2.
+**
+** If OP_KeyAsData is to be applied to cursor P1, it must be executed
+** before this op-code.
+*/
+case OP_SetNumColumns: {       /* no-push */
+Cursor *pC;
+assert( (pOp->p1)<p->nCursor );
+assert( p->apCsr[pOp->p1]!=0 );
+pC = p->apCsr[pOp->p1];
+pC->nField = pOp->p2;
+break;
+}
+/* Opcode: Column P1 P2 P3
+**
+** Interpret the data that cursor P1 points to as a structure built using
+** the MakeRecord instruction.  (See the MakeRecord opcode for additional
+** information about the format of the data.) Push onto the stack the value
+** of the P2-th column contained in the data. If there are less that (P2+1)
+** values in the record, push a NULL onto the stack.
+**
+** If the KeyAsData opcode has previously executed on this cursor, then the
+** field might be extracted from the key rather than the data.
+**
+** If the column contains fewer than P2 fields, then push a NULL.  Or
+** if P3 is of type P3_MEM, then push the P3 value.  The P3 value will
+** be default value for a column that has been added using the ALTER TABLE
+** ADD COLUMN command.  If P3 is an ordinary string, just push a NULL.
+** When P3 is a string it is really just a comment describing the value
+** to be pushed, not a default value.
+*/
+case OP_Column: {
+u32 payloadSize;   /* Number of bytes in the record */
+int p1 = pOp->p1;  /* P1 value of the opcode */
+int p2 = pOp->p2;  /* column number to retrieve */
+Cursor *pC = 0;    /* The VDBE cursor */
+char *zRec;        /* Pointer to complete record-data */
+BtCursor *pCrsr;   /* The BTree cursor */
+u32 *aType;        /* aType[i] holds the numeric type of the i-th column */
+u32 *aOffset;      /* aOffset[i] is offset to start of data for i-th column */
+u32 nField;        /* number of fields in the record */
+int len;           /* The length of the serialized data for the column */
+int i;             /* Loop counter */
+char *zData;       /* Part of the record being decoded */
+Mem sMem;          /* For storing the record being decoded */
+sMem.flags = 0;
+assert( p1<p->nCursor );
+pTos++;
+pTos->flags = MEM_Null;
+/* This block sets the variable payloadSize to be the total number of
+** bytes in the record.
+**
+** zRec is set to be the complete text of the record if it is available.
+** The complete record text is always available for pseudo-tables
+** If the record is stored in a cursor, the complete record text
+** might be available in the  pC->aRow cache.  Or it might not be.
+** If the data is unavailable,  zRec is set to NULL.
+**
+** We also compute the number of columns in the record.  For cursors,
+** the number of columns is stored in the Cursor.nField element.  For
+** records on the stack, the next entry down on the stack is an integer
+** which is the number of records.
+*/
+pC = p->apCsr[p1];
+assert( pC!=0 );
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+assert( pC->pVtabCursor==0 );
+#endif
+if( pC->pCursor!=0 ){
+/* The record is stored in a B-Tree */
+rc = sqlite3VdbeCursorMoveto(pC);
+if( rc ) goto abort_due_to_error;
+zRec = 0;
+pCrsr = pC->pCursor;
+if( pC->nullRow ){
+payloadSize = 0;
+}else if( pC->cacheStatus==p->cacheCtr ){
+payloadSize = pC->payloadSize;
+zRec = (char*)pC->aRow;
+}else if( pC->isIndex ){
+i64 payloadSize64;
+sqlite3BtreeKeySize(pCrsr, &payloadSize64);
+payloadSize = payloadSize64;
+}else{
+sqlite3BtreeDataSize(pCrsr, &payloadSize);
+}
+nField = pC->nField;
+}else if( pC->pseudoTable ){
+/* The record is the sole entry of a pseudo-table */
+payloadSize = pC->nData;
+zRec = pC->pData;
+pC->cacheStatus = CACHE_STALE;
+assert( payloadSize==0 || zRec!=0 );
+nField = pC->nField;
+pCrsr = 0;
+}else{
+zRec = 0;
+payloadSize = 0;
+pCrsr = 0;
+nField = 0;
+}
+/* If payloadSize is 0, then just push a NULL onto the stack. */
+if( payloadSize==0 ){
+assert( pTos->flags==MEM_Null );
+break;
+}
+if( payloadSize>SQLITE_MAX_LENGTH ){
+goto too_big;
+}
+assert( p2<nField );
+/* Read and parse the table header.  Store the results of the parse
+** into the record header cache fields of the cursor.
+*/
+if( pC && pC->cacheStatus==p->cacheCtr ){
+aType = pC->aType;
+aOffset = pC->aOffset;
+}else{
+u8 *zIdx;        /* Index into header */
+u8 *zEndHdr;     /* Pointer to first byte after the header */
+u32 offset;      /* Offset into the data */
+int szHdrSz;     /* Size of the header size field at start of record */
+int avail;       /* Number of bytes of available data */
+aType = pC->aType;
+if( aType==0 ){
+pC->aType = aType = (u32*)sqlite3DbMallocRaw(db, 2*nField*sizeof(aType) );
+}
+if( aType==0 ){
+goto no_mem;
+}
+pC->aOffset = aOffset = &aType[nField];
+pC->payloadSize = payloadSize;
+pC->cacheStatus = p->cacheCtr;
+/* Figure out how many bytes are in the header */
+if( zRec ){
+zData = zRec;
+}else{
+if( pC->isIndex ){
+zData = (char*)sqlite3BtreeKeyFetch(pCrsr, &avail);
+}else{
+zData = (char*)sqlite3BtreeDataFetch(pCrsr, &avail);
+}
+/* If KeyFetch()/DataFetch() managed to get the entire payload,
+** save the payload in the pC->aRow cache.  That will save us from
+** having to make additional calls to fetch the content portion of
+** the record.
+*/
+if( avail>=payloadSize ){
+zRec = zData;
+pC->aRow = (u8*)zData;
+}else{
+pC->aRow = 0;
+}
+}
+/* The following assert is true in all cases accept when
+** the database file has been corrupted externally.
+**    assert( zRec!=0 || avail>=payloadSize || avail>=9 ); */
+szHdrSz = GetVarint((u8*)zData, offset);
+/* The KeyFetch() or DataFetch() above are fast and will get the entire
+** record header in most cases.  But they will fail to get the complete
+** record header if the record header does not fit on a single page
+** in the B-Tree.  When that happens, use sqlite3VdbeMemFromBtree() to
+** acquire the complete header text.
+*/
+if( !zRec && avail<offset ){
+rc = sqlite3VdbeMemFromBtree(pCrsr, 0, offset, pC->isIndex, &sMem);
+if( rc!=SQLITE_OK ){
+goto op_column_out;
+}
+zData = sMem.z;
+}
+zEndHdr = (u8 *)&zData[offset];
+zIdx = (u8 *)&zData[szHdrSz];
+/* Scan the header and use it to fill in the aType[] and aOffset[]
+** arrays.  aType[i] will contain the type integer for the i-th
+** column and aOffset[i] will contain the offset from the beginning
+** of the record to the start of the data for the i-th column
+*/
+for(i=0; i<nField; i++){
+if( zIdx<zEndHdr ){
+aOffset[i] = offset;
+zIdx += GetVarint(zIdx, aType[i]);
+offset += sqlite3VdbeSerialTypeLen(aType[i]);
+}else{
+/* If i is less that nField, then there are less fields in this
+** record than SetNumColumns indicated there are columns in the
+** table. Set the offset for any extra columns not present in
+** the record to 0. This tells code below to push a NULL onto the
+** stack instead of deserializing a value from the record.
+*/
+aOffset[i] = 0;
+}
+}
+Release(&sMem);
+sMem.flags = MEM_Null;
+/* If we have read more header data than was contained in the header,
+** or if the end of the last field appears to be past the end of the
+** record, then we must be dealing with a corrupt database.
+*/
+if( zIdx>zEndHdr || offset>payloadSize ){
+rc = SQLITE_CORRUPT_BKPT;
+goto op_column_out;
+}
+}
+/* Get the column information. If aOffset[p2] is non-zero, then
+** deserialize the value from the record. If aOffset[p2] is zero,
+** then there are not enough fields in the record to satisfy the
+** request.  In this case, set the value NULL or to P3 if P3 is
+** a pointer to a Mem object.
+*/
+if( aOffset[p2] ){
+assert( rc==SQLITE_OK );
+if( zRec ){
+zData = &zRec[aOffset[p2]];
+}else{
+len = sqlite3VdbeSerialTypeLen(aType[p2]);
+rc = sqlite3VdbeMemFromBtree(pCrsr, aOffset[p2], len, pC->isIndex, &sMem);
+if( rc!=SQLITE_OK ){
+goto op_column_out;
+}
+zData = sMem.z;
+}
+sqlite3VdbeSerialGet((u8*)zData, aType[p2], pTos);
+pTos->enc = encoding;
+}else{
+if( pOp->p3type==P3_MEM ){
+sqlite3VdbeMemShallowCopy(pTos, (Mem *)(pOp->p3), MEM_Static);
+}else{
+pTos->flags = MEM_Null;
+}
+}
+/* If we dynamically allocated space to hold the data (in the
+** sqlite3VdbeMemFromBtree() call above) then transfer control of that
+** dynamically allocated space over to the pTos structure.
+** This prevents a memory copy.
+*/
+if( (sMem.flags & MEM_Dyn)!=0 ){
+assert( pTos->flags & MEM_Ephem );
+assert( pTos->flags & (MEM_Str|MEM_Blob) );
+assert( pTos->z==sMem.z );
+assert( sMem.flags & MEM_Term );
+pTos->flags &= ~MEM_Ephem;
+pTos->flags |= MEM_Dyn|MEM_Term;
+}
+/* pTos->z might be pointing to sMem.zShort[].  Fix that so that we
+** can abandon sMem */
+rc = sqlite3VdbeMemMakeWriteable(pTos);
+op_column_out:
+break;
+}
+/* Opcode: MakeRecord P1 P2 P3
+**
+** Convert the top abs(P1) entries of the stack into a single entry
+** suitable for use as a data record in a database table or as a key
+** in an index.  The details of the format are irrelavant as long as
+** the OP_Column opcode can decode the record later and as long as the
+** sqlite3VdbeRecordCompare function will correctly compare two encoded
+** records.  Refer to source code comments for the details of the record
+** format.
+**
+** The original stack entries are popped from the stack if P1>0 but
+** remain on the stack if P1<0.
+**
+** If P2 is not zero and one or more of the entries are NULL, then jump
+** to the address given by P2.  This feature can be used to skip a
+** uniqueness test on indices.
+**
+** P3 may be a string that is P1 characters long.  The nth character of the
+** string indicates the column affinity that should be used for the nth
+** field of the index key (i.e. the first character of P3 corresponds to the
+** lowest element on the stack).
+**
+** The mapping from character to affinity is given by the SQLITE_AFF_
+** macros defined in sqliteInt.h.
+**
+** If P3 is NULL then all index fields have the affinity NONE.
+**
+** See also OP_MakeIdxRec
+*/
+/* Opcode: MakeIdxRec P1 P2 P3
+**
+** This opcode works just OP_MakeRecord except that it reads an extra
+** integer from the stack (thus reading a total of abs(P1+1) entries)
+** and appends that extra integer to the end of the record as a varint.
+** This results in an index key.
+*/
+case OP_MakeIdxRec:
+case OP_MakeRecord: {
+/* Assuming the record contains N fields, the record format looks
+** like this:
+**
+** ------------------------------------------------------------------------
+** | hdr-size | type 0 | type 1 | ... | type N-1 | data0 | ... | data N-1 |
+** ------------------------------------------------------------------------
+**
+** Data(0) is taken from the lowest element of the stack and data(N-1) is
+** the top of the stack.
+**
+** Each type field is a varint representing the serial type of the
+** corresponding data element (see sqlite3VdbeSerialType()). The
+** hdr-size field is also a varint which is the offset from the beginning
+** of the record to data0.
+*/
+u8 *zNewRecord;        /* A buffer to hold the data for the new record */
+Mem *pRec;             /* The new record */
+Mem *pRowid = 0;       /* Rowid appended to the new record */
+u64 nData = 0;         /* Number of bytes of data space */
+int nHdr = 0;          /* Number of bytes of header space */
+u64 nByte = 0;         /* Data space required for this record */
+int nZero = 0;         /* Number of zero bytes at the end of the record */
+int nVarint;           /* Number of bytes in a varint */
+u32 serial_type;       /* Type field */
+int containsNull = 0;  /* True if any of the data fields are NULL */
+Mem *pData0;           /* Bottom of the stack */
+int leaveOnStack;      /* If true, leave the entries on the stack */
+int nField;            /* Number of fields in the record */
+int jumpIfNull;        /* Jump here if non-zero and any entries are NULL. */
+int addRowid;          /* True to append a rowid column at the end */
+char *zAffinity;       /* The affinity string for the record */
+int file_format;       /* File format to use for encoding */
+int i;                 /* Space used in zNewRecord[] */
+char zTemp[NBFS];      /* Space to hold small records */
+leaveOnStack = ((pOp->p1<0)?1:0);
+nField = pOp->p1 * (leaveOnStack?-1:1);
+jumpIfNull = pOp->p2;
+addRowid = pOp->opcode==OP_MakeIdxRec;
+zAffinity = pOp->p3;
+pData0 = &pTos[1-nField];
+assert( pData0>=p->aStack );
+containsNull = 0;
+file_format = p->minWriteFileFormat;
+/* Loop through the elements that will make up the record to figure
+** out how much space is required for the new record.
+*/
+for(pRec=pData0; pRec<=pTos; pRec++){
+int len;
+if( zAffinity ){
+applyAffinity(pRec, zAffinity[pRec-pData0], encoding);
+}
+if( pRec->flags&MEM_Null ){
+containsNull = 1;
+}
+if( pRec->flags&MEM_Zero && pRec->n>0 ){
+ExpandBlob(pRec);
+}
+serial_type = sqlite3VdbeSerialType(pRec, file_format);
+len = sqlite3VdbeSerialTypeLen(serial_type);
+nData += len;
+nHdr += sqlite3VarintLen(serial_type);
+if( pRec->flags & MEM_Zero ){
+/* Only pure zero-filled BLOBs can be input to this Opcode.
+** We do not allow blobs with a prefix and a zero-filled tail. */
+nZero += pRec->u.i;
+}else if( len ){
+nZero = 0;
+}
+}
+/* If we have to append a varint rowid to this record, set pRowid
+** to the value of the rowid and increase nByte by the amount of space
+** required to store it.
+*/
+if( addRowid ){
+pRowid = &pTos[0-nField];
+assert( pRowid>=p->aStack );
+sqlite3VdbeMemIntegerify(pRowid);
+serial_type = sqlite3VdbeSerialType(pRowid, 0);
+nData += sqlite3VdbeSerialTypeLen(serial_type);
+nHdr += sqlite3VarintLen(serial_type);
+nZero = 0;
+}
+/* Add the initial header varint and total the size */
+nHdr += nVarint = sqlite3VarintLen(nHdr);
+if( nVarint<sqlite3VarintLen(nHdr) ){
+nHdr++;
+}
+nByte = nHdr+nData-nZero;
+if( nByte>SQLITE_MAX_LENGTH ){
+goto too_big;
+}
+/* Allocate space for the new record. */
+if( nByte>sizeof(zTemp) ){
+zNewRecord = (u8*)sqlite3DbMallocRaw(db, nByte);
+if( !zNewRecord ){
+goto no_mem;
+}
+}else{
+zNewRecord = (u8*)zTemp;
+}
+/* Write the record */
+i = sqlite3PutVarint(zNewRecord, nHdr);
+for(pRec=pData0; pRec<=pTos; pRec++){
+serial_type = sqlite3VdbeSerialType(pRec, file_format);
+i += sqlite3PutVarint(&zNewRecord[i], serial_type);      /* serial type */
+}
+if( addRowid ){
+i += sqlite3PutVarint(&zNewRecord[i], sqlite3VdbeSerialType(pRowid, 0));
+}
+for(pRec=pData0; pRec<=pTos; pRec++){  /* serial data */
+i += sqlite3VdbeSerialPut(&zNewRecord[i], nByte-i, pRec, file_format);
+}
+if( addRowid ){
+i += sqlite3VdbeSerialPut(&zNewRecord[i], nByte-i, pRowid, 0);
+}
+assert( i==nByte );
+/* Pop entries off the stack if required. Push the new record on. */
+if( !leaveOnStack ){
+popStack(&pTos, nField+addRowid);
+}
+pTos++;
+pTos->n = nByte;
+if( nByte<=sizeof(zTemp) ){
+assert( zNewRecord==(unsigned char *)zTemp );
+pTos->z = pTos->zShort;
+memcpy(pTos->zShort, zTemp, nByte);
+pTos->flags = MEM_Blob | MEM_Short;
+}else{
+assert( zNewRecord!=(unsigned char *)zTemp );
+pTos->z = (char*)zNewRecord;
+pTos->flags = MEM_Blob | MEM_Dyn;
+pTos->xDel = 0;
+}
+if( nZero ){
+pTos->u.i = nZero;
+pTos->flags |= MEM_Zero;
+}
+pTos->enc = SQLITE_UTF8;  /* In case the blob is ever converted to text */
+/* If a NULL was encountered and jumpIfNull is non-zero, take the jump. */
+if( jumpIfNull && containsNull ){
+pc = jumpIfNull - 1;
+}
+break;
+}
+/* Opcode: Statement P1 * *
+**
+** Begin an individual statement transaction which is part of a larger
+** BEGIN..COMMIT transaction.  This is needed so that the statement
+** can be rolled back after an error without having to roll back the
+** entire transaction.  The statement transaction will automatically
+** commit when the VDBE halts.
+**
+** The statement is begun on the database file with index P1.  The main
+** database file has an index of 0 and the file used for temporary tables
+** has an index of 1.
+*/
+case OP_Statement: {       /* no-push */
+int i = pOp->p1;
+Btree *pBt;
+if( i>=0 && i<db->nDb && (pBt = db->aDb[i].pBt)!=0
+&& (db->autoCommit==0 || db->activeVdbeCnt>1) ){
+assert( sqlite3BtreeIsInTrans(pBt) );
+assert( (p->btreeMask & (1<<i))!=0 );
+if( !sqlite3BtreeIsInStmt(pBt) ){
+rc = sqlite3BtreeBeginStmt(pBt);
+p->openedStatement = 1;
+}
+}
+break;
+}
+/* Opcode: AutoCommit P1 P2 *
+**
+** Set the database auto-commit flag to P1 (1 or 0). If P2 is true, roll
+** back any currently active btree transactions. If there are any active
+** VMs (apart from this one), then the COMMIT or ROLLBACK statement fails.
+**
+** This instruction causes the VM to halt.
+*/
+case OP_AutoCommit: {       /* no-push */
+u8 i = pOp->p1;
+u8 rollback = pOp->p2;
+assert( i==1 || i==0 );
+assert( i==1 || rollback==0 );
+assert( db->activeVdbeCnt>0 );  /* At least this one VM is active */
+if( db->activeVdbeCnt>1 && i && !db->autoCommit ){
+/* If this instruction implements a COMMIT or ROLLBACK, other VMs are
+** still running, and a transaction is active, return an error indicating
+** that the other VMs must complete first.
+*/
+sqlite3SetString(&p->zErrMsg, "cannot ", rollback?"rollback":"commit",
+" transaction - SQL statements in progress", (char*)0);
+rc = SQLITE_ERROR;
+}else if( i!=db->autoCommit ){
+if( pOp->p2 ){
+assert( i==1 );
+sqlite3RollbackAll(db);
+db->autoCommit = 1;
+}else{
+db->autoCommit = i;
+if( sqlite3VdbeHalt(p)==SQLITE_BUSY ){
+p->pTos = pTos;
+p->pc = pc;
+db->autoCommit = 1-i;
+p->rc = rc = SQLITE_BUSY;
+goto vdbe_return;
+}
+}
+if( p->rc==SQLITE_OK ){
+rc = SQLITE_DONE;
+}else{
+rc = SQLITE_ERROR;
+}
+goto vdbe_return;
+}else{
+sqlite3SetString(&p->zErrMsg,
+(!i)?"cannot start a transaction within a transaction":(
+(rollback)?"cannot rollback - no transaction is active":
+"cannot commit - no transaction is active"), (char*)0);
+rc = SQLITE_ERROR;
+}
+break;
+}
+/* Opcode: Transaction P1 P2 *
+**
+** Begin a transaction.  The transaction ends when a Commit or Rollback
+** opcode is encountered.  Depending on the ON CONFLICT setting, the
+** transaction might also be rolled back if an error is encountered.
+**
+** P1 is the index of the database file on which the transaction is
+** started.  Index 0 is the main database file and index 1 is the
+** file used for temporary tables.
+**
+** If P2 is non-zero, then a write-transaction is started.  A RESERVED lock is
+** obtained on the database file when a write-transaction is started.  No
+** other process can start another write transaction while this transaction is
+** underway.  Starting a write transaction also creates a rollback journal. A
+** write transaction must be started before any changes can be made to the
+** database.  If P2 is 2 or greater then an EXCLUSIVE lock is also obtained
+** on the file.
+**
+** If P2 is zero, then a read-lock is obtained on the database file.
+*/
+case OP_Transaction: {       /* no-push */
+int i = pOp->p1;
+Btree *pBt;
+assert( i>=0 && i<db->nDb );
+assert( (p->btreeMask & (1<<i))!=0 );
+pBt = db->aDb[i].pBt;
+if( pBt ){
+rc = sqlite3BtreeBeginTrans(pBt, pOp->p2);
+if( rc==SQLITE_BUSY ){
+p->pc = pc;
+p->rc = rc = SQLITE_BUSY;
+p->pTos = pTos;
+goto vdbe_return;
+}
+if( rc!=SQLITE_OK && rc!=SQLITE_READONLY /* && rc!=SQLITE_BUSY */ ){
+goto abort_due_to_error;
+}
+}
+break;
+}
+/* Opcode: ReadCookie P1 P2 *
+**
+** Read cookie number P2 from database P1 and push it onto the stack.
+** P2==0 is the schema version.  P2==1 is the database format.
+** P2==2 is the recommended pager cache size, and so forth.  P1==0 is
+** the main database file and P1==1 is the database file used to store
+** temporary tables.
+**
+** If P1 is negative, then this is a request to read the size of a
+** databases free-list. P2 must be set to 1 in this case. The actual
+** database accessed is ((P1+1)*-1). For example, a P1 parameter of -1
+** corresponds to database 0 ("main"), a P1 of -2 is database 1 ("temp").
+**
+** There must be a read-lock on the database (either a transaction
+** must be started or there must be an open cursor) before
+** executing this instruction.
+*/
+case OP_ReadCookie: {
+int iMeta;
+int iDb = pOp->p1;
+int iCookie = pOp->p2;
+assert( pOp->p2<SQLITE_N_BTREE_META );
+if( iDb<0 ){
+iDb = (-1*(iDb+1));
+iCookie *= -1;
+}
+assert( iDb>=0 && iDb<db->nDb );
+assert( db->aDb[iDb].pBt!=0 );
+assert( (p->btreeMask & (1<<iDb))!=0 );
+/* The indexing of meta values at the schema layer is off by one from
+** the indexing in the btree layer.  The btree considers meta[0] to
+** be the number of free pages in the database (a read-only value)
+** and meta[1] to be the schema cookie.  The schema layer considers
+** meta[1] to be the schema cookie.  So we have to shift the index
+** by one in the following statement.
+*/
+rc = sqlite3BtreeGetMeta(db->aDb[iDb].pBt, 1 + iCookie, (u32 *)&iMeta);
+pTos++;
+pTos->u.i = iMeta;
+pTos->flags = MEM_Int;
+break;
+}
+/* Opcode: SetCookie P1 P2 *
+**
+** Write the top of the stack into cookie number P2 of database P1.
+** P2==0 is the schema version.  P2==1 is the database format.
+** P2==2 is the recommended pager cache size, and so forth.  P1==0 is
+** the main database file and P1==1 is the database file used to store
+** temporary tables.
+**
+** A transaction must be started before executing this opcode.
+*/
+case OP_SetCookie: {       /* no-push */
+Db *pDb;
+assert( pOp->p2<SQLITE_N_BTREE_META );
+assert( pOp->p1>=0 && pOp->p1<db->nDb );
+assert( (p->btreeMask & (1<<pOp->p1))!=0 );
+pDb = &db->aDb[pOp->p1];
+assert( pDb->pBt!=0 );
+assert( pTos>=p->aStack );
+sqlite3VdbeMemIntegerify(pTos);
+/* See note about index shifting on OP_ReadCookie */
+rc = sqlite3BtreeUpdateMeta(pDb->pBt, 1+pOp->p2, (int)pTos->u.i);
+if( pOp->p2==0 ){
+/* When the schema cookie changes, record the new cookie internally */
+pDb->pSchema->schema_cookie = pTos->u.i;
+db->flags |= SQLITE_InternChanges;
+}else if( pOp->p2==1 ){
+/* Record changes in the file format */
+pDb->pSchema->file_format = pTos->u.i;
+}
+assert( (pTos->flags & MEM_Dyn)==0 );
+pTos--;
+if( pOp->p1==1 ){
+/* Invalidate all prepared statements whenever the TEMP database
+** schema is changed.  Ticket #1644 */
+sqlite3ExpirePreparedStatements(db);
+}
+break;
+}
+/* Opcode: VerifyCookie P1 P2 *
+**
+** Check the value of global database parameter number 0 (the
+** schema version) and make sure it is equal to P2.
+** P1 is the database number which is 0 for the main database file
+** and 1 for the file holding temporary tables and some higher number
+** for auxiliary databases.
+**
+** The cookie changes its value whenever the database schema changes.
+** This operation is used to detect when that the cookie has changed
+** and that the current process needs to reread the schema.
+**
+** Either a transaction needs to have been started or an OP_Open needs
+** to be executed (to establish a read lock) before this opcode is
+** invoked.
+*/
+case OP_VerifyCookie: {       /* no-push */
+int iMeta;
+Btree *pBt;
+assert( pOp->p1>=0 && pOp->p1<db->nDb );
+assert( (p->btreeMask & (1<<pOp->p1))!=0 );
+pBt = db->aDb[pOp->p1].pBt;
+if( pBt ){
+rc = sqlite3BtreeGetMeta(pBt, 1, (u32 *)&iMeta);
+}else{
+rc = SQLITE_OK;
+iMeta = 0;
+}
+if( rc==SQLITE_OK && iMeta!=pOp->p2 ){
+sqlite3_free(p->zErrMsg);
+p->zErrMsg = sqlite3DbStrDup(db, "database schema has changed");
+/* If the schema-cookie from the database file matches the cookie
+** stored with the in-memory representation of the schema, do
+** not reload the schema from the database file.
+**
+** If virtual-tables are in use, this is not just an optimisation.
+** Often, v-tables store their data in other SQLite tables, which
+** are queried from within xNext() and other v-table methods using
+** prepared queries. If such a query is out-of-date, we do not want to
+** discard the database schema, as the user code implementing the
+** v-table would have to be ready for the sqlite3_vtab structure itself
+** to be invalidated whenever sqlite3_step() is called from within
+** a v-table method.
+*/
+if( db->aDb[pOp->p1].pSchema->schema_cookie!=iMeta ){
+sqlite3ResetInternalSchema(db, pOp->p1);
+}
+sqlite3ExpirePreparedStatements(db);
+rc = SQLITE_SCHEMA;
+}
+break;
+}
+/* Opcode: OpenRead P1 P2 P3
+**
+** Open a read-only cursor for the database table whose root page is
+** P2 in a database file.  The database file is determined by an
+** integer from the top of the stack.  0 means the main database and
+** 1 means the database used for temporary tables.  Give the new
+** cursor an identifier of P1.  The P1 values need not be contiguous
+** but all P1 values should be small integers.  It is an error for
+** P1 to be negative.
+**
+** If P2==0 then take the root page number from the next of the stack.
+**
+** There will be a read lock on the database whenever there is an
+** open cursor.  If the database was unlocked prior to this instruction
+** then a read lock is acquired as part of this instruction.  A read
+** lock allows other processes to read the database but prohibits
+** any other process from modifying the database.  The read lock is
+** released when all cursors are closed.  If this instruction attempts
+** to get a read lock but fails, the script terminates with an
+** SQLITE_BUSY error code.
+**
+** The P3 value is a pointer to a KeyInfo structure that defines the
+** content and collating sequence of indices.  P3 is NULL for cursors
+** that are not pointing to indices.
+**
+** See also OpenWrite.
+*/
+/* Opcode: OpenWrite P1 P2 P3
+**
+** Open a read/write cursor named P1 on the table or index whose root
+** page is P2.  If P2==0 then take the root page number from the stack.
+**
+** The P3 value is a pointer to a KeyInfo structure that defines the
+** content and collating sequence of indices.  P3 is NULL for cursors
+** that are not pointing to indices.
+**
+** This instruction works just like OpenRead except that it opens the cursor
+** in read/write mode.  For a given table, there can be one or more read-only
+** cursors or a single read/write cursor but not both.
+**
+** See also OpenRead.
+*/
+case OP_OpenRead:          /* no-push */
+case OP_OpenWrite: {       /* no-push */
+int i = pOp->p1;
+int p2 = pOp->p2;
+int wrFlag;
+Btree *pX;
+int iDb;
+Cursor *pCur;
+Db *pDb;
+assert( pTos>=p->aStack );
+sqlite3VdbeMemIntegerify(pTos);
+iDb = pTos->u.i;
+assert( (pTos->flags & MEM_Dyn)==0 );
+pTos--;
+assert( iDb>=0 && iDb<db->nDb );
+assert( (p->btreeMask & (1<<iDb))!=0 );
+pDb = &db->aDb[iDb];
+pX = pDb->pBt;
+assert( pX!=0 );
+if( pOp->opcode==OP_OpenWrite ){
+wrFlag = 1;
+if( pDb->pSchema->file_format < p->minWriteFileFormat ){
+p->minWriteFileFormat = pDb->pSchema->file_format;
+}
+}else{
+wrFlag = 0;
+}
+if( p2<=0 ){
+assert( pTos>=p->aStack );
+sqlite3VdbeMemIntegerify(pTos);
+p2 = pTos->u.i;
+assert( (pTos->flags & MEM_Dyn)==0 );
+pTos--;
+assert( p2>=2 );
+}
+assert( i>=0 );
+pCur = allocateCursor(p, i, iDb);
+if( pCur==0 ) goto no_mem;
+pCur->nullRow = 1;
+if( pX==0 ) break;
+/* We always provide a key comparison function.  If the table being
+** opened is of type INTKEY, the comparision function will be ignored. */
+rc = sqlite3BtreeCursor(pX, p2, wrFlag,
+sqlite3VdbeRecordCompare, pOp->p3,
+&pCur->pCursor);
+if( pOp->p3type==P3_KEYINFO ){
+pCur->pKeyInfo = (KeyInfo*)pOp->p3;
+pCur->pIncrKey = &pCur->pKeyInfo->incrKey;
+pCur->pKeyInfo->enc = ENC(p->db);
+}else{
+pCur->pKeyInfo = 0;
+pCur->pIncrKey = &pCur->bogusIncrKey;
+}
+switch( rc ){
+case SQLITE_BUSY: {
+p->pc = pc;
+p->rc = rc = SQLITE_BUSY;
+p->pTos = &pTos[1 + (pOp->p2<=0)]; /* Operands must remain on stack */
+goto vdbe_return;
+}
+case SQLITE_OK: {
+int flags = sqlite3BtreeFlags(pCur->pCursor);
+/* Sanity checking.  Only the lower four bits of the flags byte should
+** be used.  Bit 3 (mask 0x08) is unpreditable.  The lower 3 bits
+** (mask 0x07) should be either 5 (intkey+leafdata for tables) or
+** 2 (zerodata for indices).  If these conditions are not met it can
+** only mean that we are dealing with a corrupt database file
+*/
+if( (flags & 0xf0)!=0 || ((flags & 0x07)!=5 && (flags & 0x07)!=2) ){
+rc = SQLITE_CORRUPT_BKPT;
+goto abort_due_to_error;
+}
+pCur->isTable = (flags & BTREE_INTKEY)!=0;
+pCur->isIndex = (flags & BTREE_ZERODATA)!=0;
+/* If P3==0 it means we are expected to open a table.  If P3!=0 then
+** we expect to be opening an index.  If this is not what happened,
+** then the database is corrupt
+*/
+if( (pCur->isTable && pOp->p3type==P3_KEYINFO)
+|| (pCur->isIndex && pOp->p3type!=P3_KEYINFO) ){
+rc = SQLITE_CORRUPT_BKPT;
+goto abort_due_to_error;
+}
+break;
+}
+case SQLITE_EMPTY: {
+pCur->isTable = pOp->p3type!=P3_KEYINFO;
+pCur->isIndex = !pCur->isTable;
+rc = SQLITE_OK;
+break;
+}
+default: {
+goto abort_due_to_error;
+}
+}
+break;
+}
+/* Opcode: OpenEphemeral P1 P2 P3
+**
+** Open a new cursor P1 to a transient table.
+** The cursor is always opened read/write even if
+** the main database is read-only.  The transient or virtual
+** table is deleted automatically when the cursor is closed.
+**
+** P2 is the number of columns in the virtual table.
+** The cursor points to a BTree table if P3==0 and to a BTree index
+** if P3 is not 0.  If P3 is not NULL, it points to a KeyInfo structure
+** that defines the format of keys in the index.
+**
+** This opcode was once called OpenTemp.  But that created
+** confusion because the term "temp table", might refer either
+** to a TEMP table at the SQL level, or to a table opened by
+** this opcode.  Then this opcode was call OpenVirtual.  But
+** that created confusion with the whole virtual-table idea.
+*/
+case OP_OpenEphemeral: {       /* no-push */
+int i = pOp->p1;
+Cursor *pCx;
+static const int openFlags =
+SQLITE_OPEN_READWRITE |
+SQLITE_OPEN_CREATE |
+SQLITE_OPEN_EXCLUSIVE |
+SQLITE_OPEN_DELETEONCLOSE |
+SQLITE_OPEN_TRANSIENT_DB;
+assert( i>=0 );
+pCx = allocateCursor(p, i, -1);
+if( pCx==0 ) goto no_mem;
+pCx->nullRow = 1;
+rc = sqlite3BtreeFactory(db, 0, 1, SQLITE_DEFAULT_TEMP_CACHE_SIZE, openFlags,
+&pCx->pBt);
+if( rc==SQLITE_OK ){
+rc = sqlite3BtreeBeginTrans(pCx->pBt, 1);
+}
+if( rc==SQLITE_OK ){
+/* If a transient index is required, create it by calling
+** sqlite3BtreeCreateTable() with the BTREE_ZERODATA flag before
+** opening it. If a transient table is required, just use the
+** automatically created table with root-page 1 (an INTKEY table).
+*/
+if( pOp->p3 ){
+int pgno;
+assert( pOp->p3type==P3_KEYINFO );
+rc = sqlite3BtreeCreateTable(pCx->pBt, &pgno, BTREE_ZERODATA);
+if( rc==SQLITE_OK ){
+assert( pgno==MASTER_ROOT+1 );
+rc = sqlite3BtreeCursor(pCx->pBt, pgno, 1, sqlite3VdbeRecordCompare,
+pOp->p3, &pCx->pCursor);
+pCx->pKeyInfo = (KeyInfo*)pOp->p3;
+pCx->pKeyInfo->enc = ENC(p->db);
+pCx->pIncrKey = &pCx->pKeyInfo->incrKey;
+}
+pCx->isTable = 0;
+}else{
+rc = sqlite3BtreeCursor(pCx->pBt, MASTER_ROOT, 1, 0, 0, &pCx->pCursor);
+pCx->isTable = 1;
+pCx->pIncrKey = &pCx->bogusIncrKey;
+}
+}
+pCx->nField = pOp->p2;
+pCx->isIndex = !pCx->isTable;
+break;
+}
+/* Opcode: OpenPseudo P1 * *
+**
+** Open a new cursor that points to a fake table that contains a single
+** row of data.  Any attempt to write a second row of data causes the
+** first row to be deleted.  All data is deleted when the cursor is
+** closed.
+**
+** A pseudo-table created by this opcode is useful for holding the
+** NEW or OLD tables in a trigger.  Also used to hold the a single
+** row output from the sorter so that the row can be decomposed into
+** individual columns using the OP_Column opcode.
+*/
+case OP_OpenPseudo: {       /* no-push */
+int i = pOp->p1;
+Cursor *pCx;
+assert( i>=0 );
+pCx = allocateCursor(p, i, -1);
+if( pCx==0 ) goto no_mem;
+pCx->nullRow = 1;
+pCx->pseudoTable = 1;
+pCx->pIncrKey = &pCx->bogusIncrKey;
+pCx->isTable = 1;
+pCx->isIndex = 0;
+break;
+}
+/* Opcode: Close P1 * *
+**
+** Close a cursor previously opened as P1.  If P1 is not
+** currently open, this instruction is a no-op.
+*/
+case OP_Close: {       /* no-push */
+int i = pOp->p1;
+if( i>=0 && i<p->nCursor ){
+sqlite3VdbeFreeCursor(p, p->apCsr[i]);
+p->apCsr[i] = 0;
+}
+break;
+}
+/* Opcode: MoveGe P1 P2 *
+**
+** Pop the top of the stack and use its value as a key.  Reposition
+** cursor P1 so that it points to the smallest entry that is greater
+** than or equal to the key that was popped ffrom the stack.
+** If there are no records greater than or equal to the key and P2
+** is not zero, then jump to P2.
+**
+** See also: Found, NotFound, Distinct, MoveLt, MoveGt, MoveLe
+*/
+/* Opcode: MoveGt P1 P2 *
+**
+** Pop the top of the stack and use its value as a key.  Reposition
+** cursor P1 so that it points to the smallest entry that is greater
+** than the key from the stack.
+** If there are no records greater than the key and P2 is not zero,
+** then jump to P2.
+**
+** See also: Found, NotFound, Distinct, MoveLt, MoveGe, MoveLe
+*/
+/* Opcode: MoveLt P1 P2 *
+**
+** Pop the top of the stack and use its value as a key.  Reposition
+** cursor P1 so that it points to the largest entry that is less
+** than the key from the stack.
+** If there are no records less than the key and P2 is not zero,
+** then jump to P2.
+**
+** See also: Found, NotFound, Distinct, MoveGt, MoveGe, MoveLe
+*/
+/* Opcode: MoveLe P1 P2 *
+**
+** Pop the top of the stack and use its value as a key.  Reposition
+** cursor P1 so that it points to the largest entry that is less than
+** or equal to the key that was popped from the stack.
+** If there are no records less than or eqal to the key and P2 is not zero,
+** then jump to P2.
+**
+** See also: Found, NotFound, Distinct, MoveGt, MoveGe, MoveLt
+*/
+case OP_MoveLt:         /* no-push */
+case OP_MoveLe:         /* no-push */
+case OP_MoveGe:         /* no-push */
+case OP_MoveGt: {       /* no-push */
+int i = pOp->p1;
+Cursor *pC;
+assert( pTos>=p->aStack );
+assert( i>=0 && i<p->nCursor );
+pC = p->apCsr[i];
+assert( pC!=0 );
+if( pC->pCursor!=0 ){
+int res, oc;
+oc = pOp->opcode;
+pC->nullRow = 0;
+*pC->pIncrKey = oc==OP_MoveGt || oc==OP_MoveLe;
+if( pC->isTable ){
+i64 iKey;
+sqlite3VdbeMemIntegerify(pTos);
+iKey = intToKey(pTos->u.i);
+if( pOp->p2==0 && pOp->opcode==OP_MoveGe ){
+pC->movetoTarget = iKey;
+pC->deferredMoveto = 1;
+assert( (pTos->flags & MEM_Dyn)==0 );
+pTos--;
+break;
+}
+rc = sqlite3BtreeMoveto(pC->pCursor, 0, (u64)iKey, 0, &res);
+if( rc!=SQLITE_OK ){
+goto abort_due_to_error;
+}
+pC->lastRowid = pTos->u.i;
+pC->rowidIsValid = res==0;
+}else{
+assert( pTos->flags & MEM_Blob );
+ExpandBlob(pTos);
+rc = sqlite3BtreeMoveto(pC->pCursor, pTos->z, pTos->n, 0, &res);
+if( rc!=SQLITE_OK ){
+goto abort_due_to_error;
+}
+pC->rowidIsValid = 0;
+}
+pC->deferredMoveto = 0;
+pC->cacheStatus = CACHE_STALE;
+*pC->pIncrKey = 0;
+#ifdef SQLITE_TEST
+sqlite3_search_count++;
+#endif
+if( oc==OP_MoveGe || oc==OP_MoveGt ){
+if( res<0 ){
+rc = sqlite3BtreeNext(pC->pCursor, &res);
+if( rc!=SQLITE_OK ) goto abort_due_to_error;
+pC->rowidIsValid = 0;
+}else{
+res = 0;
+}
+}else{
+assert( oc==OP_MoveLt || oc==OP_MoveLe );
+if( res>=0 ){
+rc = sqlite3BtreePrevious(pC->pCursor, &res);
+if( rc!=SQLITE_OK ) goto abort_due_to_error;
+pC->rowidIsValid = 0;
+}else{
+/* res might be negative because the table is empty.  Check to
+** see if this is the case.
+*/
+res = sqlite3BtreeEof(pC->pCursor);
+}
+}
+if( res ){
+if( pOp->p2>0 ){
+pc = pOp->p2 - 1;
+}else{
+pC->nullRow = 1;
+}
+}
+}
+Release(pTos);
+pTos--;
+break;
+}
+/* Opcode: Distinct P1 P2 *
+**
+** Use the top of the stack as a record created using MakeRecord.  P1 is a
+** cursor on a table that declared as an index.  If that table contains an
+** entry that matches the top of the stack fall thru.  If the top of the stack
+** matches no entry in P1 then jump to P2.
+**
+** The cursor is left pointing at the matching entry if it exists.  The
+** record on the top of the stack is not popped.
+**
+** This instruction is similar to NotFound except that this operation
+** does not pop the key from the stack.
+**
+** The instruction is used to implement the DISTINCT operator on SELECT
+** statements.  The P1 table is not a true index but rather a record of
+** all results that have produced so far.
+**
+** See also: Found, NotFound, MoveTo, IsUnique, NotExists
+*/
+/* Opcode: Found P1 P2 *
+**
+** Top of the stack holds a blob constructed by MakeRecord.  P1 is an index.
+** If an entry that matches the top of the stack exists in P1 then
+** jump to P2.  If the top of the stack does not match any entry in P1
+** then fall thru.  The P1 cursor is left pointing at the matching entry
+** if it exists.  The blob is popped off the top of the stack.
+**
+** This instruction is used to implement the IN operator where the
+** left-hand side is a SELECT statement.  P1 may be a true index, or it
+** may be a temporary index that holds the results of the SELECT
+** statement.
+**
+** This instruction checks if index P1 contains a record for which
+** the first N serialised values exactly match the N serialised values
+** in the record on the stack, where N is the total number of values in
+** the stack record (stack record is a prefix of the P1 record).
+**
+** See also: Distinct, NotFound, MoveTo, IsUnique, NotExists
+*/
+/* Opcode: NotFound P1 P2 *
+**
+** The top of the stack holds a blob constructed by MakeRecord.  P1 is
+** an index.  If no entry exists in P1 that matches the blob then jump
+** to P2.  If an entry does existing, fall through.  The cursor is left
+** pointing to the entry that matches.  The blob is popped from the stack.
+**
+** The difference between this operation and Distinct is that
+** Distinct does not pop the key from the stack.
+**
+** See also: Distinct, Found, MoveTo, NotExists, IsUnique
+*/
+case OP_Distinct:       /* no-push */
+case OP_NotFound:       /* no-push */
+case OP_Found: {        /* no-push */
+int i = pOp->p1;
+int alreadyExists = 0;
+Cursor *pC;
+assert( pTos>=p->aStack );
+assert( i>=0 && i<p->nCursor );
+assert( p->apCsr[i]!=0 );
+if( (pC = p->apCsr[i])->pCursor!=0 ){
+int res;
+assert( pC->isTable==0 );
+assert( pTos->flags & MEM_Blob );
+Stringify(pTos, encoding);
+if( pOp->opcode==OP_Found ){
+pC->pKeyInfo->prefixIsEqual = 1;
+}
+rc = sqlite3BtreeMoveto(pC->pCursor, pTos->z, pTos->n, 0, &res);
+pC->pKeyInfo->prefixIsEqual = 0;
+if( rc!=SQLITE_OK ){
+break;
+}
+alreadyExists = (res==0);
+pC->deferredMoveto = 0;
+pC->cacheStatus = CACHE_STALE;
+}
+if( pOp->opcode==OP_Found ){
+if( alreadyExists ) pc = pOp->p2 - 1;
+}else{
+if( !alreadyExists ) pc = pOp->p2 - 1;
+}
+if( pOp->opcode!=OP_Distinct ){
+Release(pTos);
+pTos--;
+}
+break;
+}
+/* Opcode: IsUnique P1 P2 *
+**
+** The top of the stack is an integer record number.  Call this
+** record number R.  The next on the stack is an index key created
+** using MakeIdxRec.  Call it K.  This instruction pops R from the
+** stack but it leaves K unchanged.
+**
+** P1 is an index.  So it has no data and its key consists of a
+** record generated by OP_MakeRecord where the last field is the
+** rowid of the entry that the index refers to.
+**
+** This instruction asks if there is an entry in P1 where the
+** fields matches K but the rowid is different from R.
+** If there is no such entry, then there is an immediate
+** jump to P2.  If any entry does exist where the index string
+** matches K but the record number is not R, then the record
+** number for that entry is pushed onto the stack and control
+** falls through to the next instruction.
+**
+** See also: Distinct, NotFound, NotExists, Found
+*/
+case OP_IsUnique: {        /* no-push */
+int i = pOp->p1;
+Mem *pNos = &pTos[-1];
+Cursor *pCx;
+BtCursor *pCrsr;
+i64 R;
+/* Pop the value R off the top of the stack
+*/
+assert( pNos>=p->aStack );
+sqlite3VdbeMemIntegerify(pTos);
+R = pTos->u.i;
+assert( (pTos->flags & MEM_Dyn)==0 );
+pTos--;
+assert( i>=0 && i<p->nCursor );
+pCx = p->apCsr[i];
+assert( pCx!=0 );
+pCrsr = pCx->pCursor;
+if( pCrsr!=0 ){
+int res;
+i64 v;         /* The record number on the P1 entry that matches K */
+char *zKey;    /* The value of K */
+int nKey;      /* Number of bytes in K */
+int len;       /* Number of bytes in K without the rowid at the end */
+int szRowid;   /* Size of the rowid column at the end of zKey */
+/* Make sure K is a string and make zKey point to K
+*/
+assert( pNos->flags & MEM_Blob );
+Stringify(pNos, encoding);
+zKey = pNos->z;
+nKey = pNos->n;
+szRowid = sqlite3VdbeIdxRowidLen((u8*)zKey);
+len = nKey-szRowid;
+/* Search for an entry in P1 where all but the last four bytes match K.
+** If there is no such entry, jump immediately to P2.
+*/
+assert( pCx->deferredMoveto==0 );
+pCx->cacheStatus = CACHE_STALE;
+rc = sqlite3BtreeMoveto(pCrsr, zKey, len, 0, &res);
+if( rc!=SQLITE_OK ){
+goto abort_due_to_error;
+}
+if( res<0 ){
+rc = sqlite3BtreeNext(pCrsr, &res);
+if( res ){
+pc = pOp->p2 - 1;
+break;
+}
+}
+rc = sqlite3VdbeIdxKeyCompare(pCx, len, (u8*)zKey, &res);
+if( rc!=SQLITE_OK ) goto abort_due_to_error;
+if( res>0 ){
+pc = pOp->p2 - 1;
+break;
+}
+/* At this point, pCrsr is pointing to an entry in P1 where all but
+** the final entry (the rowid) matches K.  Check to see if the
+** final rowid column is different from R.  If it equals R then jump
+** immediately to P2.
+*/
+rc = sqlite3VdbeIdxRowid(pCrsr, &v);
+if( rc!=SQLITE_OK ){
+goto abort_due_to_error;
+}
+if( v==R ){
+pc = pOp->p2 - 1;
+break;
+}
+/* The final varint of the key is different from R.  Push it onto
+** the stack.  (The record number of an entry that violates a UNIQUE
+** constraint.)
+*/
+pTos++;
+pTos->u.i = v;
+pTos->flags = MEM_Int;
+}
+break;
+}
+/* Opcode: NotExists P1 P2 *
+**
+** Use the top of the stack as a integer key.  If a record with that key
+** does not exist in table of P1, then jump to P2.  If the record
+** does exist, then fall thru.  The cursor is left pointing to the
+** record if it exists.  The integer key is popped from the stack.
+**
+** The difference between this operation and NotFound is that this
+** operation assumes the key is an integer and that P1 is a table whereas
+** NotFound assumes key is a blob constructed from MakeRecord and
+** P1 is an index.
+**
+** See also: Distinct, Found, MoveTo, NotFound, IsUnique
+*/
+case OP_NotExists: {        /* no-push */
+int i = pOp->p1;
+Cursor *pC;
+BtCursor *pCrsr;
+assert( pTos>=p->aStack );
+assert( i>=0 && i<p->nCursor );
+assert( p->apCsr[i]!=0 );
+if( (pCrsr = (pC = p->apCsr[i])->pCursor)!=0 ){
+int res;
+u64 iKey;
+assert( pTos->flags & MEM_Int );
+assert( p->apCsr[i]->isTable );
+iKey = intToKey(pTos->u.i);
+rc = sqlite3BtreeMoveto(pCrsr, 0, iKey, 0,&res);
+pC->lastRowid = pTos->u.i;
+pC->rowidIsValid = res==0;
+pC->nullRow = 0;
+pC->cacheStatus = CACHE_STALE;
+/* res might be uninitialized if rc!=SQLITE_OK.  But if rc!=SQLITE_OK
+** processing is about to abort so we really do not care whether or not
+** the following jump is taken.  (In other words, do not stress over
+** the error that valgrind sometimes shows on the next statement when
+** running ioerr.test and similar failure-recovery test scripts.) */
+if( res!=0 ){
+pc = pOp->p2 - 1;
+pC->rowidIsValid = 0;
+}
+}
+Release(pTos);
+pTos--;
+break;
+}
+/* Opcode: Sequence P1 * *
+**
+** Push an integer onto the stack which is the next available
+** sequence number for cursor P1.  The sequence number on the
+** cursor is incremented after the push.
+*/
+case OP_Sequence: {
+int i = pOp->p1;
+assert( pTos>=p->aStack );
+assert( i>=0 && i<p->nCursor );
+assert( p->apCsr[i]!=0 );
+pTos++;
+pTos->u.i = p->apCsr[i]->seqCount++;
+pTos->flags = MEM_Int;
+break;
+}
+/* Opcode: NewRowid P1 P2 *
+**
+** Get a new integer record number (a.k.a "rowid") used as the key to a table.
+** The record number is not previously used as a key in the database
+** table that cursor P1 points to.  The new record number is pushed
+** onto the stack.
+**
+** If P2>0 then P2 is a memory cell that holds the largest previously
+** generated record number.  No new record numbers are allowed to be less
+** than this value.  When this value reaches its maximum, a SQLITE_FULL
+** error is generated.  The P2 memory cell is updated with the generated
+** record number.  This P2 mechanism is used to help implement the
+** AUTOINCREMENT feature.
+*/
+case OP_NewRowid: {
+int i = pOp->p1;
+i64 v = 0;
+Cursor *pC;
+assert( i>=0 && i<p->nCursor );
+assert( p->apCsr[i]!=0 );
+if( (pC = p->apCsr[i])->pCursor==0 ){
+/* The zero initialization above is all that is needed */
+}else{
+/* The next rowid or record number (different terms for the same
+** thing) is obtained in a two-step algorithm.
+**
+** First we attempt to find the largest existing rowid and add one
+** to that.  But if the largest existing rowid is already the maximum
+** positive integer, we have to fall through to the second
+** probabilistic algorithm
+**
+** The second algorithm is to select a rowid at random and see if
+** it already exists in the table.  If it does not exist, we have
+** succeeded.  If the random rowid does exist, we select a new one
+** and try again, up to 1000 times.
+**
+** For a table with less than 2 billion entries, the probability
+** of not finding a unused rowid is about 1.0e-300.  This is a
+** non-zero probability, but it is still vanishingly small and should
+** never cause a problem.  You are much, much more likely to have a
+** hardware failure than for this algorithm to fail.
+**
+** The analysis in the previous paragraph assumes that you have a good
+** source of random numbers.  Is a library function like lrand48()
+** good enough?  Maybe. Maybe not. It's hard to know whether there
+** might be subtle bugs is some implementations of lrand48() that
+** could cause problems. To avoid uncertainty, SQLite uses its own
+** random number generator based on the RC4 algorithm.
+**
+** To promote locality of reference for repetitive inserts, the
+** first few attempts at chosing a random rowid pick values just a little
+** larger than the previous rowid.  This has been shown experimentally
+** to double the speed of the COPY operation.
+*/
+int res, rx=SQLITE_OK, cnt;
+i64 x;
+cnt = 0;
+if( (sqlite3BtreeFlags(pC->pCursor)&(BTREE_INTKEY|BTREE_ZERODATA)) !=
+BTREE_INTKEY ){
+rc = SQLITE_CORRUPT_BKPT;
+goto abort_due_to_error;
+}
+assert( (sqlite3BtreeFlags(pC->pCursor) & BTREE_INTKEY)!=0 );
+assert( (sqlite3BtreeFlags(pC->pCursor) & BTREE_ZERODATA)==0 );
+#ifdef SQLITE_32BIT_ROWID
+#   define MAX_ROWID 0x7fffffff
+#else
+/* Some compilers complain about constants of the form 0x7fffffffffffffff.
+** Others complain about 0x7ffffffffffffffffLL.  The following macro seems
+** to provide the constant while making all compilers happy.
+*/
+#   define MAX_ROWID  ( (((u64)0x7fffffff)<<32) | (u64)0xffffffff )
+#endif
+if( !pC->useRandomRowid ){
+if( pC->nextRowidValid ){
+v = pC->nextRowid;
+}else{
+rc = sqlite3BtreeLast(pC->pCursor, &res);
+if( rc!=SQLITE_OK ){
+goto abort_due_to_error;
+}
+if( res ){
+v = 1;
+}else{
+sqlite3BtreeKeySize(pC->pCursor, &v);
+v = keyToInt(v);
+if( v==MAX_ROWID ){
+pC->useRandomRowid = 1;
+}else{
+v++;
+}
+}
+}
+#ifndef SQLITE_OMIT_AUTOINCREMENT
+if( pOp->p2 ){
+Mem *pMem;
+assert( pOp->p2>0 && pOp->p2<p->nMem );  /* P2 is a valid memory cell */
+pMem = &p->aMem[pOp->p2];
+sqlite3VdbeMemIntegerify(pMem);
+assert( (pMem->flags & MEM_Int)!=0 );  /* mem(P2) holds an integer */
+if( pMem->u.i==MAX_ROWID || pC->useRandomRowid ){
+rc = SQLITE_FULL;
+goto abort_due_to_error;
+}
+if( v<pMem->u.i+1 ){
+v = pMem->u.i + 1;
+}
+pMem->u.i = v;
+}
+#endif
+if( v<MAX_ROWID ){
+pC->nextRowidValid = 1;
+pC->nextRowid = v+1;
+}else{
+pC->nextRowidValid = 0;
+}
+}
+if( pC->useRandomRowid ){
+assert( pOp->p2==0 );  /* SQLITE_FULL must have occurred prior to this */
+v = db->priorNewRowid;
+cnt = 0;
+do{
+if( v==0 || cnt>2 ){
+sqlite3Randomness(sizeof(v), &v);
+if( cnt<5 ) v &= 0xffffff;
+}else{
+unsigned char r;
+sqlite3Randomness(1, &r);
+v += r + 1;
+}
+if( v==0 ) continue;
+x = intToKey(v);
+rx = sqlite3BtreeMoveto(pC->pCursor, 0, (u64)x, 0, &res);
+cnt++;
+}while( cnt<1000 && rx==SQLITE_OK && res==0 );
+db->priorNewRowid = v;
+if( rx==SQLITE_OK && res==0 ){
+rc = SQLITE_FULL;
+goto abort_due_to_error;
+}
+}
+pC->rowidIsValid = 0;
+pC->deferredMoveto = 0;
+pC->cacheStatus = CACHE_STALE;
+}
+pTos++;
+pTos->u.i = v;
+pTos->flags = MEM_Int;
+break;
+}
+/* Opcode: Insert P1 P2 P3
+**
+** Write an entry into the table of cursor P1.  A new entry is
+** created if it doesn't already exist or the data for an existing
+** entry is overwritten.  The data is the value on the top of the
+** stack.  The key is the next value down on the stack.  The key must
+** be an integer.  The stack is popped twice by this instruction.
+**
+** If the OPFLAG_NCHANGE flag of P2 is set, then the row change count is
+** incremented (otherwise not).  If the OPFLAG_LASTROWID flag of P2 is set,
+** then rowid is stored for subsequent return by the
+** sqlite3_last_insert_rowid() function (otherwise it is unmodified).
+**
+** Parameter P3 may point to a string containing the table-name, or
+** may be NULL. If it is not NULL, then the update-hook
+** (sqlite3.xUpdateCallback) is invoked following a successful insert.
+**
+** This instruction only works on tables.  The equivalent instruction
+** for indices is OP_IdxInsert.
+*/
+case OP_Insert: {         /* no-push */
+Mem *pNos = &pTos[-1];
+int i = pOp->p1;
+Cursor *pC;
+assert( pNos>=p->aStack );
+assert( i>=0 && i<p->nCursor );
+assert( p->apCsr[i]!=0 );
+if( ((pC = p->apCsr[i])->pCursor!=0 || pC->pseudoTable) ){
+i64 iKey;   /* The integer ROWID or key for the record to be inserted */
+assert( pNos->flags & MEM_Int );
+assert( pC->isTable );
+iKey = intToKey(pNos->u.i);
+if( pOp->p2 & OPFLAG_NCHANGE ) p->nChange++;
+if( pOp->p2 & OPFLAG_LASTROWID ) db->lastRowid = pNos->u.i;
+if( pC->nextRowidValid && pNos->u.i>=pC->nextRowid ){
+pC->nextRowidValid = 0;
+}
+if( pTos->flags & MEM_Null ){
+pTos->z = 0;
+pTos->n = 0;
+}else{
+assert( pTos->flags & (MEM_Blob|MEM_Str) );
+}
+if( pC->pseudoTable ){
+sqlite3_free(pC->pData);
+pC->iKey = iKey;
+pC->nData = pTos->n;
+if( pTos->flags & MEM_Dyn ){
+pC->pData = pTos->z;
+pTos->flags = MEM_Null;
+}else{
+pC->pData = (char*)sqlite3_malloc( pC->nData+2 );
+if( !pC->pData ) goto no_mem;
+memcpy(pC->pData, pTos->z, pC->nData);
+pC->pData[pC->nData] = 0;
+pC->pData[pC->nData+1] = 0;
+}
+pC->nullRow = 0;
+}else{
+int nZero;
+if( pTos->flags & MEM_Zero ){
+nZero = pTos->u.i;
+}else{
+nZero = 0;
+}
+rc = sqlite3BtreeInsert(pC->pCursor, 0, iKey,
+pTos->z, pTos->n, nZero,
+pOp->p2 & OPFLAG_APPEND);
+}
+pC->rowidIsValid = 0;
+pC->deferredMoveto = 0;
+pC->cacheStatus = CACHE_STALE;
+/* Invoke the update-hook if required. */
+if( rc==SQLITE_OK && db->xUpdateCallback && pOp->p3 ){
+const char *zDb = db->aDb[pC->iDb].zName;
+const char *zTbl = pOp->p3;
+int op = ((pOp->p2 & OPFLAG_ISUPDATE) ? SQLITE_UPDATE : SQLITE_INSERT);
+assert( pC->isTable );
+db->xUpdateCallback(db->pUpdateArg, op, zDb, zTbl, iKey);
+assert( pC->iDb>=0 );
+}
+}
+popStack(&pTos, 2);
+break;
+}
+/* Opcode: Delete P1 P2 P3
+**
+** Delete the record at which the P1 cursor is currently pointing.
+**
+** The cursor will be left pointing at either the next or the previous
+** record in the table. If it is left pointing at the next record, then
+** the next Next instruction will be a no-op.  Hence it is OK to delete
+** a record from within an Next loop.
+**
+** If the OPFLAG_NCHANGE flag of P2 is set, then the row change count is
+** incremented (otherwise not).
+**
+** If P1 is a pseudo-table, then this instruction is a no-op.
+*/
+case OP_Delete: {        /* no-push */
+int i = pOp->p1;
+Cursor *pC;
+assert( i>=0 && i<p->nCursor );
+pC = p->apCsr[i];
+assert( pC!=0 );
+if( pC->pCursor!=0 ){
+i64 iKey;
+/* If the update-hook will be invoked, set iKey to the rowid of the
+** row being deleted.
+*/
+if( db->xUpdateCallback && pOp->p3 ){
+assert( pC->isTable );
+if( pC->rowidIsValid ){
+iKey = pC->lastRowid;
+}else{
+rc = sqlite3BtreeKeySize(pC->pCursor, &iKey);
+if( rc ){
+goto abort_due_to_error;
+}
+iKey = keyToInt(iKey);
+}
+}
+rc = sqlite3VdbeCursorMoveto(pC);
+if( rc ) goto abort_due_to_error;
+rc = sqlite3BtreeDelete(pC->pCursor);
+pC->nextRowidValid = 0;
+pC->cacheStatus = CACHE_STALE;
+/* Invoke the update-hook if required. */
+if( rc==SQLITE_OK && db->xUpdateCallback && pOp->p3 ){
+const char *zDb = db->aDb[pC->iDb].zName;
+const char *zTbl = pOp->p3;
+db->xUpdateCallback(db->pUpdateArg, SQLITE_DELETE, zDb, zTbl, iKey);
+assert( pC->iDb>=0 );
+}
+}
+if( pOp->p2 & OPFLAG_NCHANGE ) p->nChange++;
+break;
+}
+/* Opcode: ResetCount P1 * *
+**
+** This opcode resets the VMs internal change counter to 0. If P1 is true,
+** then the value of the change counter is copied to the database handle
+** change counter (returned by subsequent calls to sqlite3_changes())
+** before it is reset. This is used by trigger programs.
+*/
+case OP_ResetCount: {        /* no-push */
+if( pOp->p1 ){
+sqlite3VdbeSetChanges(db, p->nChange);
+}
+p->nChange = 0;
+break;
+}
+/* Opcode: RowData P1 * *
+**
+** Push onto the stack the complete row data for cursor P1.
+** There is no interpretation of the data.  It is just copied
+** onto the stack exactly as it is found in the database file.
+**
+** If the cursor is not pointing to a valid row, a NULL is pushed
+** onto the stack.
+*/
+/* Opcode: RowKey P1 * *
+**
+** Push onto the stack the complete row key for cursor P1.
+** There is no interpretation of the key.  It is just copied
+** onto the stack exactly as it is found in the database file.
+**
+** If the cursor is not pointing to a valid row, a NULL is pushed
+** onto the stack.
+*/
+case OP_RowKey:
+case OP_RowData: {
+int i = pOp->p1;
+Cursor *pC;
+u32 n;
+/* Note that RowKey and RowData are really exactly the same instruction */
+pTos++;
+assert( i>=0 && i<p->nCursor );
+pC = p->apCsr[i];
+assert( pC->isTable || pOp->opcode==OP_RowKey );
+assert( pC->isIndex || pOp->opcode==OP_RowData );
+assert( pC!=0 );
+if( pC->nullRow ){
+pTos->flags = MEM_Null;
+}else if( pC->pCursor!=0 ){
+BtCursor *pCrsr = pC->pCursor;
+rc = sqlite3VdbeCursorMoveto(pC);
+if( rc ) goto abort_due_to_error;
+if( pC->nullRow ){
+pTos->flags = MEM_Null;
+break;
+}else if( pC->isIndex ){
+i64 n64;
+assert( !pC->isTable );
+sqlite3BtreeKeySize(pCrsr, &n64);
+if( n64>SQLITE_MAX_LENGTH ){
+goto too_big;
+}
+n = n64;
+}else{
+sqlite3BtreeDataSize(pCrsr, &n);
+}
+if( n>SQLITE_MAX_LENGTH ){
+goto too_big;
+}
+pTos->n = n;
+if( n<=NBFS ){
+pTos->flags = MEM_Blob | MEM_Short;
+pTos->z = pTos->zShort;
+}else{
+char *z = (char*)sqlite3_malloc( n );
+if( z==0 ) goto no_mem;
+pTos->flags = MEM_Blob | MEM_Dyn;
+pTos->xDel = 0;
+pTos->z = z;
+}
+if( pC->isIndex ){
+rc = sqlite3BtreeKey(pCrsr, 0, n, pTos->z);
+}else{
+rc = sqlite3BtreeData(pCrsr, 0, n, pTos->z);
+}
+}else if( pC->pseudoTable ){
+pTos->n = pC->nData;
+assert( pC->nData<=SQLITE_MAX_LENGTH );
+pTos->z = pC->pData;
+pTos->flags = MEM_Blob|MEM_Ephem;
+}else{
+pTos->flags = MEM_Null;
+}
+pTos->enc = SQLITE_UTF8;  /* In case the blob is ever cast to text */
+break;
+}
+/* Opcode: Rowid P1 * *
+**
+** Push onto the stack an integer which is the key of the table entry that
+** P1 is currently point to.
+*/
+case OP_Rowid: {
+int i = pOp->p1;
+Cursor *pC;
+i64 v;
+assert( i>=0 && i<p->nCursor );
+pC = p->apCsr[i];
+assert( pC!=0 );
+rc = sqlite3VdbeCursorMoveto(pC);
+if( rc ) goto abort_due_to_error;
+pTos++;
+if( pC->rowidIsValid ){
+v = pC->lastRowid;
+}else if( pC->pseudoTable ){
+v = keyToInt(pC->iKey);
+}else if( pC->nullRow || pC->pCursor==0 ){
+pTos->flags = MEM_Null;
+break;
+}else{
+assert( pC->pCursor!=0 );
+sqlite3BtreeKeySize(pC->pCursor, &v);
+v = keyToInt(v);
+}
+pTos->u.i = v;
+pTos->flags = MEM_Int;
+break;
+}
+/* Opcode: NullRow P1 * *
+**
+** Move the cursor P1 to a null row.  Any OP_Column operations
+** that occur while the cursor is on the null row will always push
+** a NULL onto the stack.
+*/
+case OP_NullRow: {        /* no-push */
+int i = pOp->p1;
+Cursor *pC;
+assert( i>=0 && i<p->nCursor );
+pC = p->apCsr[i];
+assert( pC!=0 );
+pC->nullRow = 1;
+pC->rowidIsValid = 0;
+break;
+}
+/* Opcode: Last P1 P2 *
+**
+** The next use of the Rowid or Column or Next instruction for P1
+** will refer to the last entry in the database table or index.
+** If the table or index is empty and P2>0, then jump immediately to P2.
+** If P2 is 0 or if the table or index is not empty, fall through
+** to the following instruction.
+*/
+case OP_Last: {        /* no-push */
+int i = pOp->p1;
+Cursor *pC;
+BtCursor *pCrsr;
+assert( i>=0 && i<p->nCursor );
+pC = p->apCsr[i];
+assert( pC!=0 );
+if( (pCrsr = pC->pCursor)!=0 ){
+int res;
+rc = sqlite3BtreeLast(pCrsr, &res);
+pC->nullRow = res;
+pC->deferredMoveto = 0;
+pC->cacheStatus = CACHE_STALE;
+if( res && pOp->p2>0 ){
+pc = pOp->p2 - 1;
+}
+}else{
+pC->nullRow = 0;
+}
+break;
+}
+/* Opcode: Sort P1 P2 *
+**
+** This opcode does exactly the same thing as OP_Rewind except that
+** it increments an undocumented global variable used for testing.
+**
+** Sorting is accomplished by writing records into a sorting index,
+** then rewinding that index and playing it back from beginning to
+** end.  We use the OP_Sort opcode instead of OP_Rewind to do the
+** rewinding so that the global variable will be incremented and
+** regression tests can determine whether or not the optimizer is
+** correctly optimizing out sorts.
+*/
+case OP_Sort: {        /* no-push */
+#ifdef SQLITE_TEST
+sqlite3_sort_count++;
+sqlite3_search_count--;
+#endif
+/* Fall through into OP_Rewind */
+}
+/* Opcode: Rewind P1 P2 *
+**
+** The next use of the Rowid or Column or Next instruction for P1
+** will refer to the first entry in the database table or index.
+** If the table or index is empty and P2>0, then jump immediately to P2.
+** If P2 is 0 or if the table or index is not empty, fall through
+** to the following instruction.
+*/
+case OP_Rewind: {        /* no-push */
+int i = pOp->p1;
+Cursor *pC;
+BtCursor *pCrsr;
+int res;
+assert( i>=0 && i<p->nCursor );
+pC = p->apCsr[i];
+assert( pC!=0 );
+if( (pCrsr = pC->pCursor)!=0 ){
+rc = sqlite3BtreeFirst(pCrsr, &res);
+pC->atFirst = res==0;
+pC->deferredMoveto = 0;
+pC->cacheStatus = CACHE_STALE;
+}else{
+res = 1;
+}
+pC->nullRow = res;
+if( res && pOp->p2>0 ){
+pc = pOp->p2 - 1;
+}
+break;
+}
+/* Opcode: Next P1 P2 *
+**
+** Advance cursor P1 so that it points to the next key/data pair in its
+** table or index.  If there are no more key/value pairs then fall through
+** to the following instruction.  But if the cursor advance was successful,
+** jump immediately to P2.
+**
+** See also: Prev
+*/
+/* Opcode: Prev P1 P2 *
+**
+** Back up cursor P1 so that it points to the previous key/data pair in its
+** table or index.  If there is no previous key/value pairs then fall through
+** to the following instruction.  But if the cursor backup was successful,
+** jump immediately to P2.
+*/
+case OP_Prev:          /* no-push */
+case OP_Next: {        /* no-push */
+Cursor *pC;
+BtCursor *pCrsr;
+CHECK_FOR_INTERRUPT;
+assert( pOp->p1>=0 && pOp->p1<p->nCursor );
+pC = p->apCsr[pOp->p1];
+if( pC==0 ){
+break;  /* See ticket #2273 */
+}
+if( (pCrsr = pC->pCursor)!=0 ){
+int res;
+if( pC->nullRow ){
+res = 1;
+}else{
+assert( pC->deferredMoveto==0 );
+rc = pOp->opcode==OP_Next ? sqlite3BtreeNext(pCrsr, &res) :
+sqlite3BtreePrevious(pCrsr, &res);
+pC->nullRow = res;
+pC->cacheStatus = CACHE_STALE;
+}
+if( res==0 ){
+pc = pOp->p2 - 1;
+#ifdef SQLITE_TEST
+sqlite3_search_count++;
+#endif
+}
+}else{
+pC->nullRow = 1;
+}
+pC->rowidIsValid = 0;
+break;
+}
+/* Opcode: IdxInsert P1 P2 *
+**
+** The top of the stack holds a SQL index key made using either the
+** MakeIdxRec or MakeRecord instructions.  This opcode writes that key
+** into the index P1.  Data for the entry is nil.
+**
+** P2 is a flag that provides a hint to the b-tree layer that this
+** insert is likely to be an append.
+**
+** This instruction only works for indices.  The equivalent instruction
+** for tables is OP_Insert.
+*/
+case OP_IdxInsert: {        /* no-push */
+int i = pOp->p1;
+Cursor *pC;
+BtCursor *pCrsr;
+assert( pTos>=p->aStack );
+assert( i>=0 && i<p->nCursor );
+assert( p->apCsr[i]!=0 );
+assert( pTos->flags & MEM_Blob );
+if( (pCrsr = (pC = p->apCsr[i])->pCursor)!=0 ){
+assert( pC->isTable==0 );
+rc = ExpandBlob(pTos);
+if( rc==SQLITE_OK ){
+int nKey = pTos->n;
+const char *zKey = pTos->z;
+rc = sqlite3BtreeInsert(pCrsr, zKey, nKey, "", 0, 0, pOp->p2);
+assert( pC->deferredMoveto==0 );
+pC->cacheStatus = CACHE_STALE;
+}
+}
+Release(pTos);
+pTos--;
+break;
+}
+/* Opcode: IdxDelete P1 * *
+**
+** The top of the stack is an index key built using the either the
+** MakeIdxRec or MakeRecord opcodes.
+** This opcode removes that entry from the index.
+*/
+case OP_IdxDelete: {        /* no-push */
+int i = pOp->p1;
+Cursor *pC;
+BtCursor *pCrsr;
+assert( pTos>=p->aStack );
+assert( pTos->flags & MEM_Blob );
+assert( i>=0 && i<p->nCursor );
+assert( p->apCsr[i]!=0 );
+if( (pCrsr = (pC = p->apCsr[i])->pCursor)!=0 ){
+int res;
+rc = sqlite3BtreeMoveto(pCrsr, pTos->z, pTos->n, 0, &res);
+if( rc==SQLITE_OK && res==0 ){
+rc = sqlite3BtreeDelete(pCrsr);
+}
+assert( pC->deferredMoveto==0 );
+pC->cacheStatus = CACHE_STALE;
+}
+Release(pTos);
+pTos--;
+break;
+}
+/* Opcode: IdxRowid P1 * *
+**
+** Push onto the stack an integer which is the last entry in the record at
+** the end of the index key pointed to by cursor P1.  This integer should be
+** the rowid of the table entry to which this index entry points.
+**
+** See also: Rowid, MakeIdxRec.
+*/
+case OP_IdxRowid: {
+int i = pOp->p1;
+BtCursor *pCrsr;
+Cursor *pC;
+assert( i>=0 && i<p->nCursor );
+assert( p->apCsr[i]!=0 );
+pTos++;
+pTos->flags = MEM_Null;
+if( (pCrsr = (pC = p->apCsr[i])->pCursor)!=0 ){
+i64 rowid;
+assert( pC->deferredMoveto==0 );
+assert( pC->isTable==0 );
+if( pC->nullRow ){
+pTos->flags = MEM_Null;
+}else{
+rc = sqlite3VdbeIdxRowid(pCrsr, &rowid);
+if( rc!=SQLITE_OK ){
+goto abort_due_to_error;
+}
+pTos->flags = MEM_Int;
+pTos->u.i = rowid;
+}
+}
+break;
+}
+/* Opcode: IdxGT P1 P2 *
+**
+** The top of the stack is an index entry that omits the ROWID.  Compare
+** the top of stack against the index that P1 is currently pointing to.
+** Ignore the ROWID on the P1 index.
+**
+** The top of the stack might have fewer columns that P1.
+**
+** If the P1 index entry is greater than the top of the stack
+** then jump to P2.  Otherwise fall through to the next instruction.
+** In either case, the stack is popped once.
+*/
+/* Opcode: IdxGE P1 P2 P3
+**
+** The top of the stack is an index entry that omits the ROWID.  Compare
+** the top of stack against the index that P1 is currently pointing to.
+** Ignore the ROWID on the P1 index.
+**
+** If the P1 index entry is greater than or equal to the top of the stack
+** then jump to P2.  Otherwise fall through to the next instruction.
+** In either case, the stack is popped once.
+**
+** If P3 is the "+" string (or any other non-NULL string) then the
+** index taken from the top of the stack is temporarily increased by
+** an epsilon prior to the comparison.  This make the opcode work
+** like IdxGT except that if the key from the stack is a prefix of
+** the key in the cursor, the result is false whereas it would be
+** true with IdxGT.
+*/
+/* Opcode: IdxLT P1 P2 P3
+**
+** The top of the stack is an index entry that omits the ROWID.  Compare
+** the top of stack against the index that P1 is currently pointing to.
+** Ignore the ROWID on the P1 index.
+**
+** If the P1 index entry is less than  the top of the stack
+** then jump to P2.  Otherwise fall through to the next instruction.
+** In either case, the stack is popped once.
+**
+** If P3 is the "+" string (or any other non-NULL string) then the
+** index taken from the top of the stack is temporarily increased by
+** an epsilon prior to the comparison.  This makes the opcode work
+** like IdxLE.
+*/
+case OP_IdxLT:          /* no-push */
+case OP_IdxGT:          /* no-push */
+case OP_IdxGE: {        /* no-push */
+int i= pOp->p1;
+Cursor *pC;
+assert( i>=0 && i<p->nCursor );
+assert( p->apCsr[i]!=0 );
+assert( pTos>=p->aStack );
+if( (pC = p->apCsr[i])->pCursor!=0 ){
+int res;
+assert( pTos->flags & MEM_Blob );  /* Created using OP_MakeRecord */
+assert( pC->deferredMoveto==0 );
+ExpandBlob(pTos);
+*pC->pIncrKey = pOp->p3!=0;
+assert( pOp->p3==0 || pOp->opcode!=OP_IdxGT );
+rc = sqlite3VdbeIdxKeyCompare(pC, pTos->n, (u8*)pTos->z, &res);
+*pC->pIncrKey = 0;
+if( rc!=SQLITE_OK ){
+break;
+}
+if( pOp->opcode==OP_IdxLT ){
+res = -res;
+}else if( pOp->opcode==OP_IdxGE ){
+res++;
+}
+if( res>0 ){
+pc = pOp->p2 - 1 ;
+}
+}
+Release(pTos);
+pTos--;
+break;
+}
+/* Opcode: Destroy P1 P2 *
+**
+** Delete an entire database table or index whose root page in the database
+** file is given by P1.
+**
+** The table being destroyed is in the main database file if P2==0.  If
+** P2==1 then the table to be clear is in the auxiliary database file
+** that is used to store tables create using CREATE TEMPORARY TABLE.
+**
+** If AUTOVACUUM is enabled then it is possible that another root page
+** might be moved into the newly deleted root page in order to keep all
+** root pages contiguous at the beginning of the database.  The former
+** value of the root page that moved - its value before the move occurred -
+** is pushed onto the stack.  If no page movement was required (because
+** the table being dropped was already the last one in the database) then
+** a zero is pushed onto the stack.  If AUTOVACUUM is disabled
+** then a zero is pushed onto the stack.
+**
+** See also: Clear
+*/
+case OP_Destroy: {
+int iMoved;
+int iCnt;
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+Vdbe *pVdbe;
+iCnt = 0;
+for(pVdbe=db->pVdbe; pVdbe; pVdbe=pVdbe->pNext){
+if( pVdbe->magic==VDBE_MAGIC_RUN && pVdbe->inVtabMethod<2 && pVdbe->pc>=0 ){
+iCnt++;
+}
+}
+#else
+iCnt = db->activeVdbeCnt;
+#endif
+if( iCnt>1 ){
+rc = SQLITE_LOCKED;
+p->errorAction = OE_Abort;
+}else{
+assert( iCnt==1 );
+assert( (p->btreeMask & (1<<pOp->p2))!=0 );
+rc = sqlite3BtreeDropTable(db->aDb[pOp->p2].pBt, pOp->p1, &iMoved);
+pTos++;
+pTos->flags = MEM_Int;
+pTos->u.i = iMoved;
+#ifndef SQLITE_OMIT_AUTOVACUUM
+if( rc==SQLITE_OK && iMoved!=0 ){
+sqlite3RootPageMoved(&db->aDb[pOp->p2], iMoved, pOp->p1);
+}
+#endif
+}
+break;
+}
+/* Opcode: Clear P1 P2 *
+**
+** Delete all contents of the database table or index whose root page
+** in the database file is given by P1.  But, unlike Destroy, do not
+** remove the table or index from the database file.
+**
+** The table being clear is in the main database file if P2==0.  If
+** P2==1 then the table to be clear is in the auxiliary database file
+** that is used to store tables create using CREATE TEMPORARY TABLE.
+**
+** See also: Destroy
+*/
+case OP_Clear: {        /* no-push */
+/* For consistency with the way other features of SQLite operate
+** with a truncate, we will also skip the update callback.
+*/
+#if 0
+Btree *pBt = db->aDb[pOp->p2].pBt;
+if( db->xUpdateCallback && pOp->p3 ){
+const char *zDb = db->aDb[pOp->p2].zName;
+const char *zTbl = pOp->p3;
+BtCursor *pCur = 0;
+int fin = 0;
+rc = sqlite3BtreeCursor(pBt, pOp->p1, 0, 0, 0, &pCur);
+if( rc!=SQLITE_OK ){
+goto abort_due_to_error;
+}
+for(
+rc=sqlite3BtreeFirst(pCur, &fin);
+rc==SQLITE_OK && !fin;
+rc=sqlite3BtreeNext(pCur, &fin)
+){
+i64 iKey;
+rc = sqlite3BtreeKeySize(pCur, &iKey);
+if( rc ){
+break;
+}
+iKey = keyToInt(iKey);
+db->xUpdateCallback(db->pUpdateArg, SQLITE_DELETE, zDb, zTbl, iKey);
+}
+sqlite3BtreeCloseCursor(pCur);
+if( rc!=SQLITE_OK ){
+goto abort_due_to_error;
+}
+}
+#endif
+assert( (p->btreeMask & (1<<pOp->p2))!=0 );
+rc = sqlite3BtreeClearTable(db->aDb[pOp->p2].pBt, pOp->p1);
+break;
+}
+/* Opcode: CreateTable P1 * *
+**
+** Allocate a new table in the main database file if P2==0 or in the
+** auxiliary database file if P2==1.  Push the page number
+** for the root page of the new table onto the stack.
+**
+** The difference between a table and an index is this:  A table must
+** have a 4-byte integer key and can have arbitrary data.  An index
+** has an arbitrary key but no data.
+**
+** See also: CreateIndex
+*/
+/* Opcode: CreateIndex P1 * *
+**
+** Allocate a new index in the main database file if P2==0 or in the
+** auxiliary database file if P2==1.  Push the page number of the
+** root page of the new index onto the stack.
+**
+** See documentation on OP_CreateTable for additional information.
+*/
+case OP_CreateIndex:
+case OP_CreateTable: {
+int pgno;
+int flags;
+Db *pDb;
+assert( pOp->p1>=0 && pOp->p1<db->nDb );
+assert( (p->btreeMask & (1<<pOp->p1))!=0 );
+pDb = &db->aDb[pOp->p1];
+assert( pDb->pBt!=0 );
+if( pOp->opcode==OP_CreateTable ){
+/* flags = BTREE_INTKEY; */
+flags = BTREE_LEAFDATA|BTREE_INTKEY;
+}else{
+flags = BTREE_ZERODATA;
+}
+rc = sqlite3BtreeCreateTable(pDb->pBt, &pgno, flags);
+pTos++;
+if( rc==SQLITE_OK ){
+pTos->u.i = pgno;
+pTos->flags = MEM_Int;
+}else{
+pTos->flags = MEM_Null;
+}
+break;
+}
+/* Opcode: ParseSchema P1 P2 P3
+**
+** Read and parse all entries from the SQLITE_MASTER table of database P1
+** that match the WHERE clause P3.  P2 is the "force" flag.   Always do
+** the parsing if P2 is true.  If P2 is false, then this routine is a
+** no-op if the schema is not currently loaded.  In other words, if P2
+** is false, the SQLITE_MASTER table is only parsed if the rest of the
+** schema is already loaded into the symbol table.
+**
+** This opcode invokes the parser to create a new virtual machine,
+** then runs the new virtual machine.  It is thus a reentrant opcode.
+*/
+case OP_ParseSchema: {        /* no-push */
+char *zSql;
+int iDb = pOp->p1;
+const char *zMaster;
+InitData initData;
+assert( iDb>=0 && iDb<db->nDb );
+if( !pOp->p2 && !DbHasProperty(db, iDb, DB_SchemaLoaded) ){
+break;
+}
+zMaster = SCHEMA_TABLE(iDb);
+initData.db = db;
+initData.iDb = pOp->p1;
+initData.pzErrMsg = &p->zErrMsg;
+zSql = sqlite3MPrintf(db,
+"SELECT name, rootpage, sql FROM '%q'.%s WHERE %s",
+db->aDb[iDb].zName, zMaster, pOp->p3);
+if( zSql==0 ) goto no_mem;
+sqlite3SafetyOff(db);
+assert( db->init.busy==0 );
+db->init.busy = 1;
+assert( !db->mallocFailed );
+rc = sqlite3_exec(db, zSql, sqlite3InitCallback, &initData, 0);
+if( rc==SQLITE_ABORT ) rc = initData.rc;
+sqlite3_free(zSql);
+db->init.busy = 0;
+sqlite3SafetyOn(db);
+if( rc==SQLITE_NOMEM ){
+goto no_mem;
+}
+break;
+}
+#if !defined(SQLITE_OMIT_ANALYZE) && !defined(SQLITE_OMIT_PARSER)
+/* Opcode: LoadAnalysis P1 * *
+**
+** Read the sqlite_stat1 table for database P1 and load the content
+** of that table into the internal index hash table.  This will cause
+** the analysis to be used when preparing all subsequent queries.
+*/
+case OP_LoadAnalysis: {        /* no-push */
+int iDb = pOp->p1;
+assert( iDb>=0 && iDb<db->nDb );
+rc = sqlite3AnalysisLoad(db, iDb);
+break;
+}
+#endif /* !defined(SQLITE_OMIT_ANALYZE) && !defined(SQLITE_OMIT_PARSER)  */
+/* Opcode: DropTable P1 * P3
+**
+** Remove the internal (in-memory) data structures that describe
+** the table named P3 in database P1.  This is called after a table
+** is dropped in order to keep the internal representation of the
+** schema consistent with what is on disk.
+*/
+case OP_DropTable: {        /* no-push */
+sqlite3UnlinkAndDeleteTable(db, pOp->p1, pOp->p3);
+break;
+}
+/* Opcode: DropIndex P1 * P3
+**
+** Remove the internal (in-memory) data structures that describe
+** the index named P3 in database P1.  This is called after an index
+** is dropped in order to keep the internal representation of the
+** schema consistent with what is on disk.
+*/
+case OP_DropIndex: {        /* no-push */
+sqlite3UnlinkAndDeleteIndex(db, pOp->p1, pOp->p3);
+break;
+}
+/* Opcode: DropTrigger P1 * P3
+**
+** Remove the internal (in-memory) data structures that describe
+** the trigger named P3 in database P1.  This is called after a trigger
+** is dropped in order to keep the internal representation of the
+** schema consistent with what is on disk.
+*/
+case OP_DropTrigger: {        /* no-push */
+sqlite3UnlinkAndDeleteTrigger(db, pOp->p1, pOp->p3);
+break;
+}
+#ifndef SQLITE_OMIT_INTEGRITY_CHECK
+/* Opcode: IntegrityCk P1 P2 *
+**
+** Do an analysis of the currently open database.  Push onto the
+** stack the text of an error message describing any problems.
+** If no problems are found, push a NULL onto the stack.
+**
+** P1 is the address of a memory cell that contains the maximum
+** number of allowed errors.  At most mem[P1] errors will be reported.
+** In other words, the analysis stops as soon as mem[P1] errors are
+** seen.  Mem[P1] is updated with the number of errors remaining.
+**
+** The root page numbers of all tables in the database are integer
+** values on the stack.  This opcode pulls as many integers as it
+** can off of the stack and uses those numbers as the root pages.
+**
+** If P2 is not zero, the check is done on the auxiliary database
+** file, not the main database file.
+**
+** This opcode is used to implement the integrity_check pragma.
+*/
+case OP_IntegrityCk: {
+int nRoot;
+int *aRoot;
+int j;
+int nErr;
+char *z;
+Mem *pnErr;
+for(nRoot=0; &pTos[-nRoot]>=p->aStack; nRoot++){
+if( (pTos[-nRoot].flags & MEM_Int)==0 ) break;
+}
+assert( nRoot>0 );
+aRoot = (int*)sqlite3_malloc( sizeof(int)*(nRoot+1) );
+if( aRoot==0 ) goto no_mem;
+j = pOp->p1;
+assert( j>=0 && j<p->nMem );
+pnErr = &p->aMem[j];
+assert( (pnErr->flags & MEM_Int)!=0 );
+for(j=0; j<nRoot; j++){
+aRoot[j] = (pTos-j)->u.i;
+}
+aRoot[j] = 0;
+popStack(&pTos, nRoot);
+pTos++;
+assert( pOp->p2>=0 && pOp->p2<db->nDb );
+assert( (p->btreeMask & (1<<pOp->p2))!=0 );
+z = sqlite3BtreeIntegrityCheck(db->aDb[pOp->p2].pBt, aRoot, nRoot,
+pnErr->u.i, &nErr);
+pnErr->u.i -= nErr;
+if( nErr==0 ){
+assert( z==0 );
+pTos->flags = MEM_Null;
+}else{
+pTos->z = z;
+pTos->n = strlen(z);
+pTos->flags = MEM_Str | MEM_Dyn | MEM_Term;
+pTos->xDel = 0;
+}
+pTos->enc = SQLITE_UTF8;
+sqlite3VdbeChangeEncoding(pTos, encoding);
+sqlite3_free(aRoot);
+break;
+}
+#endif /* SQLITE_OMIT_INTEGRITY_CHECK */
+/* Opcode: FifoWrite * * *
+**
+** Write the integer on the top of the stack
+** into the Fifo.
+*/
+case OP_FifoWrite: {        /* no-push */
+assert( pTos>=p->aStack );
+sqlite3VdbeMemIntegerify(pTos);
+if( sqlite3VdbeFifoPush(&p->sFifo, pTos->u.i)==SQLITE_NOMEM ){
+goto no_mem;
+}
+assert( (pTos->flags & MEM_Dyn)==0 );
+pTos--;
+break;
+}
+/* Opcode: FifoRead * P2 *
+**
+** Attempt to read a single integer from the Fifo
+** and push it onto the stack.  If the Fifo is empty
+** push nothing but instead jump to P2.
+*/
+case OP_FifoRead: {
+i64 v;
+CHECK_FOR_INTERRUPT;
+if( sqlite3VdbeFifoPop(&p->sFifo, &v)==SQLITE_DONE ){
+pc = pOp->p2 - 1;
+}else{
+pTos++;
+pTos->u.i = v;
+pTos->flags = MEM_Int;
+}
+break;
+}
+#ifndef SQLITE_OMIT_TRIGGER
+/* Opcode: ContextPush * * *
+**
+** Save the current Vdbe context such that it can be restored by a ContextPop
+** opcode. The context stores the last insert row id, the last statement change
+** count, and the current statement change count.
+*/
+case OP_ContextPush: {        /* no-push */
+int i = p->contextStackTop++;
+Context *pContext;
+assert( i>=0 );
+/* FIX ME: This should be allocated as part of the vdbe at compile-time */
+if( i>=p->contextStackDepth ){
+p->contextStackDepth = i+1;
+p->contextStack = (Context*)sqlite3DbReallocOrFree(db, p->contextStack,
+sizeof(Context)*(i+1));
+if( p->contextStack==0 ) goto no_mem;
+}
+pContext = &p->contextStack[i];
+pContext->lastRowid = db->lastRowid;
+pContext->nChange = p->nChange;
+pContext->sFifo = p->sFifo;
+sqlite3VdbeFifoInit(&p->sFifo);
+break;
+}
+/* Opcode: ContextPop * * *
+**
+** Restore the Vdbe context to the state it was in when contextPush was last
+** executed. The context stores the last insert row id, the last statement
+** change count, and the current statement change count.
+*/
+case OP_ContextPop: {        /* no-push */
+Context *pContext = &p->contextStack[--p->contextStackTop];
+assert( p->contextStackTop>=0 );
+db->lastRowid = pContext->lastRowid;
+p->nChange = pContext->nChange;
+sqlite3VdbeFifoClear(&p->sFifo);
+p->sFifo = pContext->sFifo;
+break;
+}
+#endif /* #ifndef SQLITE_OMIT_TRIGGER */
+/* Opcode: MemStore P1 P2 *
+**
+** Write the top of the stack into memory location P1.
+** P1 should be a small integer since space is allocated
+** for all memory locations between 0 and P1 inclusive.
+**
+** After the data is stored in the memory location, the
+** stack is popped once if P2 is 1.  If P2 is zero, then
+** the original data remains on the stack.
+*/
+case OP_MemStore: {        /* no-push */
+assert( pTos>=p->aStack );
+assert( pOp->p1>=0 && pOp->p1<p->nMem );
+rc = sqlite3VdbeMemMove(&p->aMem[pOp->p1], pTos);
+pTos--;
+/* If P2 is 0 then fall thru to the next opcode, OP_MemLoad, that will
+** restore the top of the stack to its original value.
+*/
+if( pOp->p2 ){
+break;
+}
+}
+/* Opcode: MemLoad P1 * *
+**
+** Push a copy of the value in memory location P1 onto the stack.
+**
+** If the value is a string, then the value pushed is a pointer to
+** the string that is stored in the memory location.  If the memory
+** location is subsequently changed (using OP_MemStore) then the
+** value pushed onto the stack will change too.
+*/
+case OP_MemLoad: {
+int i = pOp->p1;
+assert( i>=0 && i<p->nMem );
+pTos++;
+sqlite3VdbeMemShallowCopy(pTos, &p->aMem[i], MEM_Ephem);
+break;
+}
+#ifndef SQLITE_OMIT_AUTOINCREMENT
+/* Opcode: MemMax P1 * *
+**
+** Set the value of memory cell P1 to the maximum of its current value
+** and the value on the top of the stack.  The stack is unchanged.
+**
+** This instruction throws an error if the memory cell is not initially
+** an integer.
+*/
+case OP_MemMax: {        /* no-push */
+int i = pOp->p1;
+Mem *pMem;
+assert( pTos>=p->aStack );
+assert( i>=0 && i<p->nMem );
+pMem = &p->aMem[i];
+sqlite3VdbeMemIntegerify(pMem);
+sqlite3VdbeMemIntegerify(pTos);
+if( pMem->u.i<pTos->u.i){
+pMem->u.i = pTos->u.i;
+}
+break;
+}
+#endif /* SQLITE_OMIT_AUTOINCREMENT */
+/* Opcode: MemIncr P1 P2 *
+**
+** Increment the integer valued memory cell P2 by the value in P1.
+**
+** It is illegal to use this instruction on a memory cell that does
+** not contain an integer.  An assertion fault will result if you try.
+*/
+case OP_MemIncr: {        /* no-push */
+int i = pOp->p2;
+Mem *pMem;
+assert( i>=0 && i<p->nMem );
+pMem = &p->aMem[i];
+assert( pMem->flags==MEM_Int );
+pMem->u.i += pOp->p1;
+break;
+}
+/* Opcode: IfMemPos P1 P2 *
+**
+** If the value of memory cell P1 is 1 or greater, jump to P2.
+**
+** It is illegal to use this instruction on a memory cell that does
+** not contain an integer.  An assertion fault will result if you try.
+*/
+case OP_IfMemPos: {        /* no-push */
+int i = pOp->p1;
+Mem *pMem;
+assert( i>=0 && i<p->nMem );
+pMem = &p->aMem[i];
+assert( pMem->flags==MEM_Int );
+if( pMem->u.i>0 ){
+pc = pOp->p2 - 1;
+}
+break;
+}
+/* Opcode: IfMemNeg P1 P2 *
+**
+** If the value of memory cell P1 is less than zero, jump to P2.
+**
+** It is illegal to use this instruction on a memory cell that does
+** not contain an integer.  An assertion fault will result if you try.
+*/
+case OP_IfMemNeg: {        /* no-push */
+int i = pOp->p1;
+Mem *pMem;
+assert( i>=0 && i<p->nMem );
+pMem = &p->aMem[i];
+assert( pMem->flags==MEM_Int );
+if( pMem->u.i<0 ){
+pc = pOp->p2 - 1;
+}
+break;
+}
+/* Opcode: IfMemZero P1 P2 *
+**
+** If the value of memory cell P1 is exactly 0, jump to P2.
+**
+** It is illegal to use this instruction on a memory cell that does
+** not contain an integer.  An assertion fault will result if you try.
+*/
+case OP_IfMemZero: {        /* no-push */
+int i = pOp->p1;
+Mem *pMem;
+assert( i>=0 && i<p->nMem );
+pMem = &p->aMem[i];
+assert( pMem->flags==MEM_Int );
+if( pMem->u.i==0 ){
+pc = pOp->p2 - 1;
+}
+break;
+}
+/* Opcode: MemNull P1 * *
+**
+** Store a NULL in memory cell P1
+*/
+case OP_MemNull: {
+assert( pOp->p1>=0 && pOp->p1<p->nMem );
+sqlite3VdbeMemSetNull(&p->aMem[pOp->p1]);
+break;
+}
+/* Opcode: MemInt P1 P2 *
+**
+** Store the integer value P1 in memory cell P2.
+*/
+case OP_MemInt: {
+assert( pOp->p2>=0 && pOp->p2<p->nMem );
+sqlite3VdbeMemSetInt64(&p->aMem[pOp->p2], pOp->p1);
+break;
+}
+/* Opcode: MemMove P1 P2 *
+**
+** Move the content of memory cell P2 over to memory cell P1.
+** Any prior content of P1 is erased.  Memory cell P2 is left
+** containing a NULL.
+*/
+case OP_MemMove: {
+assert( pOp->p1>=0 && pOp->p1<p->nMem );
+assert( pOp->p2>=0 && pOp->p2<p->nMem );
+rc = sqlite3VdbeMemMove(&p->aMem[pOp->p1], &p->aMem[pOp->p2]);
+break;
+}
+/* Opcode: AggStep P1 P2 P3
+**
+** Execute the step function for an aggregate.  The
+** function has P2 arguments.  P3 is a pointer to the FuncDef
+** structure that specifies the function.  Use memory location
+** P1 as the accumulator.
+**
+** The P2 arguments are popped from the stack.
+*/
+case OP_AggStep: {        /* no-push */
+int n = pOp->p2;
+int i;
+Mem *pMem, *pRec;
+sqlite3_context ctx;
+sqlite3_value **apVal;
+assert( n>=0 );
+pRec = &pTos[1-n];
+assert( pRec>=p->aStack );
+apVal = p->apArg;
+assert( apVal || n==0 );
+for(i=0; i<n; i++, pRec++){
+apVal[i] = pRec;
+storeTypeInfo(pRec, encoding);
+}
+ctx.pFunc = (FuncDef*)pOp->p3;
+assert( pOp->p1>=0 && pOp->p1<p->nMem );
+ctx.pMem = pMem = &p->aMem[pOp->p1];
+pMem->n++;
+ctx.s.flags = MEM_Null;
+ctx.s.z = 0;
+ctx.s.xDel = 0;
+ctx.s.db = db;
+ctx.isError = 0;
+ctx.pColl = 0;
+if( ctx.pFunc->needCollSeq ){
+assert( pOp>p->aOp );
+assert( pOp[-1].p3type==P3_COLLSEQ );
+assert( pOp[-1].opcode==OP_CollSeq );
+ctx.pColl = (CollSeq *)pOp[-1].p3;
+}
+(ctx.pFunc->xStep)(&ctx, n, apVal);
+popStack(&pTos, n);
+if( ctx.isError ){
+sqlite3SetString(&p->zErrMsg, sqlite3_value_text(&ctx.s), (char*)0);
+rc = SQLITE_ERROR;
+}
+sqlite3VdbeMemRelease(&ctx.s);
+break;
+}
+/* Opcode: AggFinal P1 P2 P3
+**
+** Execute the finalizer function for an aggregate.  P1 is
+** the memory location that is the accumulator for the aggregate.
+**
+** P2 is the number of arguments that the step function takes and
+** P3 is a pointer to the FuncDef for this function.  The P2
+** argument is not used by this opcode.  It is only there to disambiguate
+** functions that can take varying numbers of arguments.  The
+** P3 argument is only needed for the degenerate case where
+** the step function was not previously called.
+*/
+case OP_AggFinal: {        /* no-push */
+Mem *pMem;
+assert( pOp->p1>=0 && pOp->p1<p->nMem );
+pMem = &p->aMem[pOp->p1];
+assert( (pMem->flags & ~(MEM_Null|MEM_Agg))==0 );
+rc = sqlite3VdbeMemFinalize(pMem, (FuncDef*)pOp->p3);
+if( rc==SQLITE_ERROR ){
+sqlite3SetString(&p->zErrMsg, sqlite3_value_text(pMem), (char*)0);
+}
+if( sqlite3VdbeMemTooBig(pMem) ){
+goto too_big;
+}
+break;
+}
+#if !defined(SQLITE_OMIT_VACUUM) && !defined(SQLITE_OMIT_ATTACH)
+/* Opcode: Vacuum * * *
+**
+** Vacuum the entire database.  This opcode will cause other virtual
+** machines to be created and run.  It may not be called from within
+** a transaction.
+*/
+case OP_Vacuum: {        /* no-push */
+if( sqlite3SafetyOff(db) ) goto abort_due_to_misuse;
+rc = sqlite3RunVacuum(&p->zErrMsg, db);
+if( sqlite3SafetyOn(db) ) goto abort_due_to_misuse;
+break;
+}
+#endif
+#if !defined(SQLITE_OMIT_AUTOVACUUM)
+/* Opcode: IncrVacuum P1 P2 *
+**
+** Perform a single step of the incremental vacuum procedure on
+** the P1 database. If the vacuum has finished, jump to instruction
+** P2. Otherwise, fall through to the next instruction.
+*/
+case OP_IncrVacuum: {        /* no-push */
+Btree *pBt;
+assert( pOp->p1>=0 && pOp->p1<db->nDb );
+assert( (p->btreeMask & (1<<pOp->p1))!=0 );
+pBt = db->aDb[pOp->p1].pBt;
+rc = sqlite3BtreeIncrVacuum(pBt);
+if( rc==SQLITE_DONE ){
+pc = pOp->p2 - 1;
+rc = SQLITE_OK;
+}
+break;
+}
+#endif
+/* Opcode: Expire P1 * *
+**
+** Cause precompiled statements to become expired. An expired statement
+** fails with an error code of SQLITE_SCHEMA if it is ever executed
+** (via sqlite3_step()).
+**
+** If P1 is 0, then all SQL statements become expired. If P1 is non-zero,
+** then only the currently executing statement is affected.
+*/
+case OP_Expire: {        /* no-push */
+if( !pOp->p1 ){
+sqlite3ExpirePreparedStatements(db);
+}else{
+p->expired = 1;
+}
+break;
+}
+#ifndef SQLITE_OMIT_SHARED_CACHE
+/* Opcode: TableLock P1 P2 P3
+**
+** Obtain a lock on a particular table. This instruction is only used when
+** the shared-cache feature is enabled.
+**
+** If P1 is not negative, then it is the index of the database
+** in sqlite3.aDb[] and a read-lock is required. If P1 is negative, a
+** write-lock is required. In this case the index of the database is the
+** absolute value of P1 minus one (iDb = abs(P1) - 1;) and a write-lock is
+** required.
+**
+** P2 contains the root-page of the table to lock.
+**
+** P3 contains a pointer to the name of the table being locked. This is only
+** used to generate an error message if the lock cannot be obtained.
+*/
+case OP_TableLock: {        /* no-push */
+int p1 = pOp->p1;
+u8 isWriteLock = (p1<0);
+if( isWriteLock ){
+p1 = (-1*p1)-1;
+}
+assert( p1>=0 && p1<db->nDb );
+assert( (p->btreeMask & (1<<p1))!=0 );
+rc = sqlite3BtreeLockTable(db->aDb[p1].pBt, pOp->p2, isWriteLock);
+if( rc==SQLITE_LOCKED ){
+const char *z = (const char *)pOp->p3;
+sqlite3SetString(&p->zErrMsg, "database table is locked: ", z, (char*)0);
+}
+break;
+}
+#endif /* SQLITE_OMIT_SHARED_CACHE */
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+/* Opcode: VBegin * * P3
+**
+** P3 a pointer to an sqlite3_vtab structure. Call the xBegin method
+** for that table.
+*/
+case OP_VBegin: {   /* no-push */
+rc = sqlite3VtabBegin(db, (sqlite3_vtab *)pOp->p3);
+break;
+}
+#endif /* SQLITE_OMIT_VIRTUALTABLE */
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+/* Opcode: VCreate P1 * P3
+**
+** P3 is the name of a virtual table in database P1. Call the xCreate method
+** for that table.
+*/
+case OP_VCreate: {   /* no-push */
+rc = sqlite3VtabCallCreate(db, pOp->p1, pOp->p3, &p->zErrMsg);
+break;
+}
+#endif /* SQLITE_OMIT_VIRTUALTABLE */
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+/* Opcode: VDestroy P1 * P3
+**
+** P3 is the name of a virtual table in database P1.  Call the xDestroy method
+** of that table.
+*/
+case OP_VDestroy: {   /* no-push */
+p->inVtabMethod = 2;
+rc = sqlite3VtabCallDestroy(db, pOp->p1, pOp->p3);
+p->inVtabMethod = 0;
+break;
+}
+#endif /* SQLITE_OMIT_VIRTUALTABLE */
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+/* Opcode: VOpen P1 * P3
+**
+** P3 is a pointer to a virtual table object, an sqlite3_vtab structure.
+** P1 is a cursor number.  This opcode opens a cursor to the virtual
+** table and stores that cursor in P1.
+*/
+case OP_VOpen: {   /* no-push */
+Cursor *pCur = 0;
+sqlite3_vtab_cursor *pVtabCursor = 0;
+sqlite3_vtab *pVtab = (sqlite3_vtab *)(pOp->p3);
+sqlite3_module *pModule = (sqlite3_module *)pVtab->pModule;
+assert(pVtab && pModule);
+if( sqlite3SafetyOff(db) ) goto abort_due_to_misuse;
+rc = pModule->xOpen(pVtab, &pVtabCursor);
+if( sqlite3SafetyOn(db) ) goto abort_due_to_misuse;
+if( SQLITE_OK==rc ){
+/* Initialise sqlite3_vtab_cursor base class */
+pVtabCursor->pVtab = pVtab;
+/* Initialise vdbe cursor object */
+pCur = allocateCursor(p, pOp->p1, -1);
+if( pCur ){
+pCur->pVtabCursor = pVtabCursor;
+pCur->pModule = pVtabCursor->pVtab->pModule;
+}else{
+db->mallocFailed = 1;
+pModule->xClose(pVtabCursor);
+}
+}
+break;
+}
+#endif /* SQLITE_OMIT_VIRTUALTABLE */
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+/* Opcode: VFilter P1 P2 P3
+**
+** P1 is a cursor opened using VOpen.  P2 is an address to jump to if
+** the filtered result set is empty.
+**
+** P3 is either NULL or a string that was generated by the xBestIndex
+** method of the module.  The interpretation of the P3 string is left
+** to the module implementation.
+**
+** This opcode invokes the xFilter method on the virtual table specified
+** by P1.  The integer query plan parameter to xFilter is the top of the
+** stack.  Next down on the stack is the argc parameter.  Beneath the
+** next of stack are argc additional parameters which are passed to
+** xFilter as argv. The topmost parameter (i.e. 3rd element popped from
+** the stack) becomes argv[argc-1] when passed to xFilter.
+**
+** The integer query plan parameter, argc, and all argv stack values
+** are popped from the stack before this instruction completes.
+**
+** A jump is made to P2 if the result set after filtering would be
+** empty.
+*/
+case OP_VFilter: {   /* no-push */
+int nArg;
+const sqlite3_module *pModule;
+Cursor *pCur = p->apCsr[pOp->p1];
+assert( pCur->pVtabCursor );
+pModule = pCur->pVtabCursor->pVtab->pModule;
+/* Grab the index number and argc parameters off the top of the stack. */
+assert( (&pTos[-1])>=p->aStack );
+assert( (pTos[0].flags&MEM_Int)!=0 && pTos[-1].flags==MEM_Int );
+nArg = pTos[-1].u.i;
+/* Invoke the xFilter method */
+{
+int res = 0;
+int i;
+Mem **apArg = p->apArg;
+for(i = 0; i<nArg; i++){
+apArg[i] = &pTos[i+1-2-nArg];
+storeTypeInfo(apArg[i], 0);
+}
+if( sqlite3SafetyOff(db) ) goto abort_due_to_misuse;
+p->inVtabMethod = 1;
+rc = pModule->xFilter(pCur->pVtabCursor, pTos->u.i, pOp->p3, nArg, apArg);
+p->inVtabMethod = 0;
+if( rc==SQLITE_OK ){
+res = pModule->xEof(pCur->pVtabCursor);
+}
+if( sqlite3SafetyOn(db) ) goto abort_due_to_misuse;
+if( res ){
+pc = pOp->p2 - 1;
+}
+}
+/* Pop the index number, argc value and parameters off the stack */
+popStack(&pTos, 2+nArg);
+break;
+}
+#endif /* SQLITE_OMIT_VIRTUALTABLE */
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+/* Opcode: VRowid P1 * *
+**
+** Push an integer onto the stack which is the rowid of
+** the virtual-table that the P1 cursor is pointing to.
+*/
+case OP_VRowid: {
+const sqlite3_module *pModule;
+Cursor *pCur = p->apCsr[pOp->p1];
+assert( pCur->pVtabCursor );
+pModule = pCur->pVtabCursor->pVtab->pModule;
+if( pModule->xRowid==0 ){
+sqlite3SetString(&p->zErrMsg, "Unsupported module operation: xRowid", 0);
+rc = SQLITE_ERROR;
+} else {
+sqlite_int64 iRow;
+if( sqlite3SafetyOff(db) ) goto abort_due_to_misuse;
+rc = pModule->xRowid(pCur->pVtabCursor, &iRow);
+if( sqlite3SafetyOn(db) ) goto abort_due_to_misuse;
+pTos++;
+pTos->flags = MEM_Int;
+pTos->u.i = iRow;
+}
+break;
+}
+#endif /* SQLITE_OMIT_VIRTUALTABLE */
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+/* Opcode: VColumn P1 P2 *
+**
+** Push onto the stack the value of the P2-th column of
+** the row of the virtual-table that the P1 cursor is pointing to.
+*/
+case OP_VColumn: {
+const sqlite3_module *pModule;
+Cursor *pCur = p->apCsr[pOp->p1];
+assert( pCur->pVtabCursor );
+pModule = pCur->pVtabCursor->pVtab->pModule;
+if( pModule->xColumn==0 ){
+sqlite3SetString(&p->zErrMsg, "Unsupported module operation: xColumn", 0);
+rc = SQLITE_ERROR;
+} else {
+sqlite3_context sContext;
+memset(&sContext, 0, sizeof(sContext));
+sContext.s.flags = MEM_Null;
+sContext.s.db = db;
+if( sqlite3SafetyOff(db) ) goto abort_due_to_misuse;
+rc = pModule->xColumn(pCur->pVtabCursor, &sContext, pOp->p2);
+/* Copy the result of the function to the top of the stack. We
+** do this regardless of whether or not an error occured to ensure any
+** dynamic allocation in sContext.s (a Mem struct) is  released.
+*/
+sqlite3VdbeChangeEncoding(&sContext.s, encoding);
+pTos++;
+pTos->flags = 0;
+sqlite3VdbeMemMove(pTos, &sContext.s);
+if( sqlite3SafetyOn(db) ){
+goto abort_due_to_misuse;
+}
+if( sqlite3VdbeMemTooBig(pTos) ){
+goto too_big;
+}
+}
+break;
+}
+#endif /* SQLITE_OMIT_VIRTUALTABLE */
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+/* Opcode: VNext P1 P2 *
+**
+** Advance virtual table P1 to the next row in its result set and
+** jump to instruction P2.  Or, if the virtual table has reached
+** the end of its result set, then fall through to the next instruction.
+*/
+case OP_VNext: {   /* no-push */
+const sqlite3_module *pModule;
+int res = 0;
+Cursor *pCur = p->apCsr[pOp->p1];
+assert( pCur->pVtabCursor );
+pModule = pCur->pVtabCursor->pVtab->pModule;
+if( pModule->xNext==0 ){
+sqlite3SetString(&p->zErrMsg, "Unsupported module operation: xNext", 0);
+rc = SQLITE_ERROR;
+} else {
+/* Invoke the xNext() method of the module. There is no way for the
+** underlying implementation to return an error if one occurs during
+** xNext(). Instead, if an error occurs, true is returned (indicating that
+** data is available) and the error code returned when xColumn or
+** some other method is next invoked on the save virtual table cursor.
+*/
+if( sqlite3SafetyOff(db) ) goto abort_due_to_misuse;
+p->inVtabMethod = 1;
+rc = pModule->xNext(pCur->pVtabCursor);
+p->inVtabMethod = 0;
+if( rc==SQLITE_OK ){
+res = pModule->xEof(pCur->pVtabCursor);
+}
+if( sqlite3SafetyOn(db) ) goto abort_due_to_misuse;
+if( !res ){
+/* If there is data, jump to P2 */
+pc = pOp->p2 - 1;
+}
+}
+break;
+}
+#endif /* SQLITE_OMIT_VIRTUALTABLE */
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+/* Opcode: VRename * * P3
+**
+** P3 is a pointer to a virtual table object, an sqlite3_vtab structure.
+** This opcode invokes the corresponding xRename method. The value
+** on the top of the stack is popped and passed as the zName argument
+** to the xRename method.
+*/
+case OP_VRename: {   /* no-push */
+sqlite3_vtab *pVtab = (sqlite3_vtab *)(pOp->p3);
+assert( pVtab->pModule->xRename );
+Stringify(pTos, encoding);
+if( sqlite3SafetyOff(db) ) goto abort_due_to_misuse;
+sqlite3VtabLock(pVtab);
+rc = pVtab->pModule->xRename(pVtab, pTos->z);
+sqlite3VtabUnlock(db, pVtab);
+if( sqlite3SafetyOn(db) ) goto abort_due_to_misuse;
+popStack(&pTos, 1);
+break;
+}
+#endif
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+/* Opcode: VUpdate P1 P2 P3
+**
+** P3 is a pointer to a virtual table object, an sqlite3_vtab structure.
+** This opcode invokes the corresponding xUpdate method. P2 values
+** are taken from the stack to pass to the xUpdate invocation. The
+** value on the top of the stack corresponds to the p2th element
+** of the argv array passed to xUpdate.
+**
+** The xUpdate method will do a DELETE or an INSERT or both.
+** The argv[0] element (which corresponds to the P2-th element down
+** on the stack) is the rowid of a row to delete.  If argv[0] is
+** NULL then no deletion occurs.  The argv[1] element is the rowid
+** of the new row.  This can be NULL to have the virtual table
+** select the new rowid for itself.  The higher elements in the
+** stack are the values of columns in the new row.
+**
+** If P2==1 then no insert is performed.  argv[0] is the rowid of
+** a row to delete.
+**
+** P1 is a boolean flag. If it is set to true and the xUpdate call
+** is successful, then the value returned by sqlite3_last_insert_rowid()
+** is set to the value of the rowid for the row just inserted.
+*/
+case OP_VUpdate: {   /* no-push */
+sqlite3_vtab *pVtab = (sqlite3_vtab *)(pOp->p3);
+sqlite3_module *pModule = (sqlite3_module *)pVtab->pModule;
+int nArg = pOp->p2;
+assert( pOp->p3type==P3_VTAB );
+if( pModule->xUpdate==0 ){
+sqlite3SetString(&p->zErrMsg, "read-only table", 0);
+rc = SQLITE_ERROR;
+}else{
+int i;
+sqlite_int64 rowid;
+Mem **apArg = p->apArg;
+Mem *pX = &pTos[1-nArg];
+for(i = 0; i<nArg; i++, pX++){
+storeTypeInfo(pX, 0);
+apArg[i] = pX;
+}
+if( sqlite3SafetyOff(db) ) goto abort_due_to_misuse;
+sqlite3VtabLock(pVtab);
+rc = pModule->xUpdate(pVtab, nArg, apArg, &rowid);
+sqlite3VtabUnlock(db, pVtab);
+if( sqlite3SafetyOn(db) ) goto abort_due_to_misuse;
+if( pOp->p1 && rc==SQLITE_OK ){
+assert( nArg>1 && apArg[0] && (apArg[0]->flags&MEM_Null) );
+db->lastRowid = rowid;
+}
+}
+popStack(&pTos, nArg);
+break;
+}
+#endif /* SQLITE_OMIT_VIRTUALTABLE */
+/* An other opcode is illegal...
+*/
+default: {
+assert( 0 );
+break;
+}
+/*****************************************************************************
+** The cases of the switch statement above this line should all be indented
+** by 6 spaces.  But the left-most 6 spaces have been removed to improve the
+** readability.  From this point on down, the normal indentation rules are
+** restored.
+*****************************************************************************/
+}
+/* Make sure the stack limit was not exceeded */
+assert( pTos<=pStackLimit );
+#ifdef VDBE_PROFILE
+{
+long long elapse = hwtime() - start;
+pOp->cycles += elapse;
+pOp->cnt++;
+#if 0
+fprintf(stdout, "%10lld ", elapse);
+sqlite3VdbePrintOp(stdout, origPc, &p->aOp[origPc]);
+#endif
+}
+#endif
+#ifdef SQLITE_TEST
+/* Keep track of the size of the largest BLOB or STR that has appeared
+** on the top of the VDBE stack.
+*/
+if( pTos>=p->aStack && (pTos->flags & (MEM_Blob|MEM_Str))!=0
+&& pTos->n>sqlite3_max_blobsize ){
+sqlite3_max_blobsize = pTos->n;
+}
+#endif
+/* The following code adds nothing to the actual functionality
+** of the program.  It is only here for testing and debugging.
+** On the other hand, it does burn CPU cycles every time through
+** the evaluator loop.  So we can leave it out when NDEBUG is defined.
+*/
+#ifndef NDEBUG
+/* Sanity checking on the top element of the stack. If the previous
+** instruction was VNoChange, then the flags field of the top
+** of the stack is set to 0. This is technically invalid for a memory
+** cell, so avoid calling MemSanity() in this case.
+*/
+if( pTos>=p->aStack && pTos->flags ){
+assert( pTos->db==db );
+sqlite3VdbeMemSanity(pTos);
+assert( !sqlite3VdbeMemTooBig(pTos) );
+}
+assert( pc>=-1 && pc<p->nOp );
+#ifdef SQLITE_DEBUG
+/* Code for tracing the vdbe stack. */
+if( p->trace && pTos>=p->aStack ){
+int i;
+fprintf(p->trace, "Stack:");
+for(i=0; i>-5 && &pTos[i]>=p->aStack; i--){
+if( pTos[i].flags & MEM_Null ){
+fprintf(p->trace, " NULL");
+}else if( (pTos[i].flags & (MEM_Int|MEM_Str))==(MEM_Int|MEM_Str) ){
+fprintf(p->trace, " si:%lld", pTos[i].u.i);
+}else if( pTos[i].flags & MEM_Int ){
+fprintf(p->trace, " i:%lld", pTos[i].u.i);
+}else if( pTos[i].flags & MEM_Real ){
+fprintf(p->trace, " r:%g", pTos[i].r);
+}else{
+char zBuf[200];
+sqlite3VdbeMemPrettyPrint(&pTos[i], zBuf);
+fprintf(p->trace, " ");
+fprintf(p->trace, "%s", zBuf);
+}
+}
+if( rc!=0 ) fprintf(p->trace," rc=%d",rc);
+fprintf(p->trace,"\n");
+}
+#endif  /* SQLITE_DEBUG */
+#endif  /* NDEBUG */
+}  /* The end of the for(;;) loop the loops through opcodes */
+/* If we reach this point, it means that execution is finished.
+*/
+vdbe_halt:
+if( rc ){
+p->rc = rc;
+rc = SQLITE_ERROR;
+}else{
+rc = SQLITE_DONE;
+}
+sqlite3VdbeHalt(p);
+p->pTos = pTos;
+/* This is the only way out of this procedure.  We have to
+** release the mutexes on btrees that were acquired at the
+** top. */
+vdbe_return:
+sqlite3BtreeMutexArrayLeave(&p->aMutex);
+return rc;
+/* Jump to here if a string or blob larger than SQLITE_MAX_LENGTH
+** is encountered.
+*/
+too_big:
+sqlite3SetString(&p->zErrMsg, "string or blob too big", (char*)0);
+rc = SQLITE_TOOBIG;
+goto vdbe_halt;
+/* Jump to here if a malloc() fails.
+*/
+no_mem:
+db->mallocFailed = 1;
+sqlite3SetString(&p->zErrMsg, "out of memory", (char*)0);
+rc = SQLITE_NOMEM;
+goto vdbe_halt;
+/* Jump to here for an SQLITE_MISUSE error.
+*/
+abort_due_to_misuse:
+rc = SQLITE_MISUSE;
+/* Fall thru into abort_due_to_error */
+/* Jump to here for any other kind of fatal error.  The "rc" variable
+** should hold the error number.
+*/
+abort_due_to_error:
+if( p->zErrMsg==0 ){
+if( db->mallocFailed ) rc = SQLITE_NOMEM;
+sqlite3SetString(&p->zErrMsg, sqlite3ErrStr(rc), (char*)0);
+}
+goto vdbe_halt;
+/* Jump to here if the sqlite3_interrupt() API sets the interrupt
+** flag.
+*/
+abort_due_to_interrupt:
+assert( db->u1.isInterrupted );
+if( db->magic!=SQLITE_MAGIC_BUSY ){
+rc = SQLITE_MISUSE;
+}else{
+rc = SQLITE_INTERRUPT;
+}
+p->rc = rc;
+sqlite3SetString(&p->zErrMsg, sqlite3ErrStr(rc), (char*)0);
+goto vdbe_halt;
+}