SQLite

** This file contains the C functions that implement various SQL
** functions of SQLite.  
**
** There is only one exported symbol in this file - the function
** sqliteRegisterBuildinFunctions() found at the bottom of the file.
** All other code has file scope.
**
** $Id: func.c,v 1.37 2004/01/19 04:53:25 jplyon Exp $
*/
#include <ctype.h>
#include <math.h>
#include <stdlib.h>
#include <assert.h>
#include "sqliteInt.h"
#include "os.h"

*/
static void minStep(sqlite_func *context, int argc, const char **argv){
  MinMaxCtx *p;
  p = sqlite_aggregate_context(context, sizeof(*p));
  if( p==0 || argc<1 || argv[0]==0 ) return;
  if( p->z==0 || sqliteCompare(argv[0],p->z)<0 ){
    int len;
    if( p->z && p->z!=p->zBuf ){
      sqliteFree(p->z);
    }
    len = strlen(argv[0]);
    if( len < sizeof(p->zBuf) ){

      p->z = p->zBuf;
    }else{
      p->z = sqliteMalloc( len+1 );

      if( p->z==0 ) return;
    }
    strcpy(p->z, argv[0]);
  }
}
static void maxStep(sqlite_func *context, int argc, const char **argv){
  MinMaxCtx *p;
  p = sqlite_aggregate_context(context, sizeof(*p));
  if( p==0 || argc<1 || argv[0]==0 ) return;
  if( p->z==0 || sqliteCompare(argv[0],p->z)>0 ){
    int len;
    if( p->z && p->z!=p->zBuf ){
      sqliteFree(p->z);
    }
    len = strlen(argv[0]);
    if( len < sizeof(p->zBuf) ){

      p->z = p->zBuf;
    }else{
      p->z = sqliteMalloc( len+1 );

      if( p->z==0 ) return;
    }
    strcpy(p->z, argv[0]);
  }
}
static void minMaxFinalize(sqlite_func *context){
  MinMaxCtx *p;
  p = sqlite_aggregate_context(context, sizeof(*p));
  if( p && p->z ){
    sqlite_set_result_string(context, p->z, strlen(p->z));
  }
  if( p && p->z && p->z!=p->zBuf ){
    sqliteFree(p->z);
  }
}

/*
** This function registered all of the above C functions as SQL
** functions.  This should be the only routine in this file with

**
** 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.c,v 1.251 2004/01/15 02:44:03 drh Exp $
*/
#include "sqliteInt.h"
#include "os.h"
#include <ctype.h>
#include "vdbeInt.h"

/*

  pOld = sqliteHashInsert(&p->hash, pElem->zKey, pElem->nKey, pElem);
  if( pOld!=0 ){
    assert( pOld==pElem );  /* Malloc failed on insert */
    sqliteFree(pOld);
    return 0;
  }
  for(i=0; i<p->nMem; i++){
    pElem->aMem[i].s.flags = STK_Null;
  }
  p->pCurrent = pElem;
  return 0;
}

/*
** Get the AggElem currently in focus

  return pElem ? sqliteHashData(pElem) : 0;
}

/*
** Convert the given stack entity into a string if it isn't one
** already.
*/
#define Stringify(P,I) if((aStack[I].flags & STK_Str)==0){hardStringify(P,I);}
static int hardStringify(Vdbe *p, int i){
  Stack *pStack = &p->aStack[i];
  int fg = pStack->flags;
  if( fg & STK_Real ){
    sqlite_snprintf(sizeof(pStack->z),pStack->z,"%.15g",pStack->r);
  }else if( fg & STK_Int ){
    sqlite_snprintf(sizeof(pStack->z),pStack->z,"%d",pStack->i);
  }else{
    pStack->z[0] = 0;
  }
  p->zStack[i] = pStack->z;
  pStack->n = strlen(pStack->z)+1;
  pStack->flags = STK_Str;
  return 0;
}

/*
** Convert the given stack entity into a string that has been obtained
** from sqliteMalloc().  This is different from Stringify() above in that
** Stringify() will use the NBFS bytes of static string space if the string
** will fit but this routine always mallocs for space.
** Return non-zero if we run out of memory.
*/
#define Dynamicify(P,I) ((aStack[I].flags & STK_Dyn)==0 ? hardDynamicify(P,I):0)
static int hardDynamicify(Vdbe *p, int i){
  Stack *pStack = &p->aStack[i];
  int fg = pStack->flags;
  char *z;
  if( (fg & STK_Str)==0 ){
    hardStringify(p, i);
  }
  assert( (fg & STK_Dyn)==0 );
  z = sqliteMallocRaw( pStack->n );
  if( z==0 ) return 1;
  memcpy(z, p->zStack[i], pStack->n);
  p->zStack[i] = z;
  pStack->flags |= STK_Dyn;
  return 0;
}

/*
** An ephemeral string value (signified by the STK_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 STK_Ephem string into an STK_Dyn string.
*/
#define Deephemeralize(P,I) \
   if( ((P)->aStack[I].flags&STK_Ephem)!=0 && hardDeephem(P,I) ){ goto no_mem;}
static int hardDeephem(Vdbe *p, int i){
  Stack *pStack = &p->aStack[i];
  char **pzStack = &p->zStack[i];
  char *z;
  assert( (pStack->flags & STK_Ephem)!=0 );
  z = sqliteMallocRaw( pStack->n );
  if( z==0 ) return 1;
  memcpy(z, *pzStack, pStack->n);
  *pzStack = z;
  pStack->flags &= ~STK_Ephem;
  pStack->flags |= STK_Dyn;
  return 0;
}

/*
** Release the memory associated with the given stack level
*/
#define Release(P,I)  if((P)->aStack[I].flags&STK_Dyn){ hardRelease(P,I); }
static void hardRelease(Vdbe *p, int i){
  sqliteFree(p->zStack[i]);
  p->zStack[i] = 0;
  p->aStack[i].flags &= ~(STK_Str|STK_Dyn|STK_Static|STK_Ephem);
}

/*
** Return TRUE if zNum is a 32-bit signed integer and write
** the value of the integer into *pNum.  If zNum is not an integer
** or is an integer that is too large to be expressed with just 32
** bits, then return false.

** Convert the given stack entity into a integer if it isn't one
** already.
**
** Any prior string or real representation is invalidated.  
** NULLs are converted into 0.
*/
#define Integerify(P,I) \
    if(((P)->aStack[(I)].flags&STK_Int)==0){ hardIntegerify(P,I); }
static void hardIntegerify(Vdbe *p, int i){
  if( p->aStack[i].flags & STK_Real ){
    p->aStack[i].i = (int)p->aStack[i].r;
    Release(p, i);
  }else if( p->aStack[i].flags & STK_Str ){
    toInt(p->zStack[i], &p->aStack[i].i);
    Release(p, i);
  }else{
    p->aStack[i].i = 0;
  }
  p->aStack[i].flags = STK_Int;
}

/*
** Get a valid Real representation for the given stack element.
**
** Any prior string or integer representation is retained.
** NULLs are converted into 0.0.
*/
#define Realify(P,I) \
    if(((P)->aStack[(I)].flags&STK_Real)==0){ hardRealify(P,I); }
static void hardRealify(Vdbe *p, int i){
  if( p->aStack[i].flags & STK_Str ){
    p->aStack[i].r = sqliteAtoF(p->zStack[i]);
  }else if( p->aStack[i].flags & STK_Int ){
    p->aStack[i].r = p->aStack[i].i;
  }else{
    p->aStack[i].r = 0.0;
  }
  p->aStack[i].flags |= STK_Real;
}

/*
** The parameters are pointers to the head of two sorted lists
** of Sorter structures.  Merge these two lists together and return
** a single sorted list.  This routine forms the core of the merge-sort
** algorithm.

int sqliteVdbeExec(
  Vdbe *p                    /* The VDBE */
){
  int pc;                    /* The program counter */
  Op *pOp;                   /* Current operation */
  int rc = SQLITE_OK;        /* Value to return */
  sqlite *db = p->db;        /* The database */
  char **zStack = p->zStack; /* Text stack */
  Stack *aStack = p->aStack; /* Additional stack information */
  char zBuf[100];            /* Space to sprintf() an integer */
#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. */

**
** The integer value P1 is pushed onto the stack.  If P3 is not zero
** then it is assumed to be a string representation of the same integer.
*/
case OP_Integer: {
  int i = ++p->tos;
  aStack[i].i = pOp->p1;
  aStack[i].flags = STK_Int;
  if( pOp->p3 ){
    zStack[i] = pOp->p3;
    aStack[i].flags |= STK_Str | STK_Static;
    aStack[i].n = strlen(pOp->p3)+1;
  }
  break;
}

/* Opcode: String * * P3
**
** The string value P3 is pushed onto the stack.  If P3==0 then a
** NULL is pushed onto the stack.
*/
case OP_String: {
  int i = ++p->tos;
  char *z;
  z = pOp->p3;
  if( z==0 ){
    zStack[i] = 0;
    aStack[i].n = 0;
    aStack[i].flags = STK_Null;
  }else{
    zStack[i] = z;
    aStack[i].n = strlen(z) + 1;
    aStack[i].flags = STK_Str | STK_Static;
  }
  break;
}

/* 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 sqlite_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
** sqlite_bind() API.
*/
case OP_Variable: {
  int i = ++p->tos;
  int j = pOp->p1 - 1;
  if( j>=0 && j<p->nVar && p->azVar[j]!=0 ){
    zStack[i] = p->azVar[j];
    aStack[i].n = p->anVar[j];
    aStack[i].flags = STK_Str | STK_Static;
  }else{
    zStack[i] = 0;
    aStack[i].n = 0;
    aStack[i].flags = STK_Null;
  }
  break;
}

/* Opcode: Pop P1 * *
**
** P1 elements are popped off of the top of stack and discarded.

** Also see the Pull instruction.
*/
case OP_Dup: {
  int i = p->tos - pOp->p1;
  int j = ++p->tos;
  VERIFY( if( i<0 ) goto not_enough_stack; )
  memcpy(&aStack[j], &aStack[i], sizeof(aStack[i])-NBFS);
  if( aStack[j].flags & STK_Str ){
    int isStatic = (aStack[j].flags & STK_Static)!=0;
    if( pOp->p2 || isStatic ){
      zStack[j] = zStack[i];
      aStack[j].flags &= ~STK_Dyn;
      if( !isStatic ) aStack[j].flags |= STK_Ephem;
    }else if( aStack[i].n<=NBFS ){
      memcpy(aStack[j].z, zStack[i], aStack[j].n);
      zStack[j] = aStack[j].z;
      aStack[j].flags &= ~(STK_Static|STK_Dyn|STK_Ephem);
    }else{
      zStack[j] = sqliteMallocRaw( aStack[j].n );
      if( zStack[j]==0 ) goto no_mem;
      memcpy(zStack[j], zStack[i], aStack[j].n);
      aStack[j].flags &= ~(STK_Static|STK_Ephem);
      aStack[j].flags |= STK_Dyn;
    }
  }
  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: {
  int from = p->tos - pOp->p1;
  int to = p->tos;
  int i;
  Stack ts;
  char *tz;
  VERIFY( if( from<0 ) goto not_enough_stack; )
  Deephemeralize(p, from);
  ts = aStack[from];
  tz = zStack[from];
  Deephemeralize(p, to);
  for(i=from; i<to; i++){
    Deephemeralize(p, i+1);
    aStack[i] = aStack[i+1];
    assert( (aStack[i].flags & STK_Ephem)==0 );
    if( aStack[i].flags & (STK_Dyn|STK_Static) ){
      zStack[i] = zStack[i+1];
    }else{
      zStack[i] = aStack[i].z;
    }
  }
  aStack[to] = ts;
  assert( (aStack[to].flags & STK_Ephem)==0 );
  if( aStack[to].flags & (STK_Dyn|STK_Static) ){
    zStack[to] = tz;
  }else{
    zStack[to] = aStack[to].z;
  }
  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: {
  int from = p->tos;
  int to = p->tos - pOp->p1;

  VERIFY( if( to<0 ) goto not_enough_stack; )
  if( aStack[to].flags & STK_Dyn ){
    sqliteFree(zStack[to]);
  }
  Deephemeralize(p, from);
  aStack[to] = aStack[from];
  if( aStack[to].flags & (STK_Dyn|STK_Static|STK_Ephem) ){
    zStack[to] = zStack[from];
  }else{
    zStack[to] = aStack[to].z;
  }
  aStack[from].flags = 0;
  p->tos--;
  break;
}

/* Opcode: ColumnName P1 * P3

** 3rd parameter.
*/
case OP_Callback: {
  int i = p->tos - pOp->p1 + 1;
  int j;
  VERIFY( if( i<0 ) goto not_enough_stack; )
  for(j=i; j<=p->tos; j++){
    if( aStack[j].flags & STK_Null ){
      zStack[j] = 0;
    }else{
      Stringify(p, j);
    }

  }
  zStack[p->tos+1] = 0;
  if( p->xCallback==0 ){
    p->azResColumn = &zStack[i];
    p->nResColumn = pOp->p1;
    p->popStack = pOp->p1;
    p->pc = pc + 1;
    return SQLITE_ROW;
  }
  if( sqliteSafetyOff(db) ) goto abort_due_to_misuse; 
  if( p->xCallback(p->pCbArg, pOp->p1, &zStack[i], p->azColName)!=0 ){
    rc = SQLITE_ABORT;
  }
  if( sqliteSafetyOn(db) ) goto abort_due_to_misuse;
  p->nCallback++;
  sqliteVdbePopStack(p, pOp->p1);
  if( sqlite_malloc_failed ) goto no_mem;
  break;

  nField = pOp->p1;
  zSep = pOp->p3;
  if( zSep==0 ) zSep = "";
  nSep = strlen(zSep);
  VERIFY( if( p->tos+1<nField ) goto not_enough_stack; )
  nByte = 1 - nSep;
  for(i=p->tos-nField+1; i<=p->tos; i++){
    if( aStack[i].flags & STK_Null ){
      nByte = -1;
      break;
    }else{
      Stringify(p, i);
      nByte += aStack[i].n - 1 + nSep;
    }
  }
  if( nByte<0 ){
    if( pOp->p2==0 ) sqliteVdbePopStack(p, nField);
    p->tos++;
    aStack[p->tos].flags = STK_Null;
    zStack[p->tos] = 0;
    break;
  }
  zNew = sqliteMallocRaw( nByte );
  if( zNew==0 ) goto no_mem;
  j = 0;
  for(i=p->tos-nField+1; i<=p->tos; i++){
    if( (aStack[i].flags & STK_Null)==0 ){
      memcpy(&zNew[j], zStack[i], aStack[i].n-1);
      j += aStack[i].n-1;
    }
    if( nSep>0 && i<p->tos ){
      memcpy(&zNew[j], zSep, nSep);
      j += nSep;
    }
  }
  zNew[j] = 0;
  if( pOp->p2==0 ) sqliteVdbePopStack(p, nField);
  p->tos++;
  aStack[p->tos].n = nByte;
  aStack[p->tos].flags = STK_Str|STK_Dyn;
  zStack[p->tos] = 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

case OP_Subtract:
case OP_Multiply:
case OP_Divide:
case OP_Remainder: {
  int tos = p->tos;
  int nos = tos - 1;
  VERIFY( if( nos<0 ) goto not_enough_stack; )
  if( ((aStack[tos].flags | aStack[nos].flags) & STK_Null)!=0 ){
    POPSTACK;
    Release(p, nos);
    aStack[nos].flags = STK_Null;
  }else if( (aStack[tos].flags & aStack[nos].flags & STK_Int)==STK_Int ){
    int a, b;
    a = aStack[tos].i;
    b = aStack[nos].i;
    switch( pOp->opcode ){
      case OP_Add:         b += a;       break;
      case OP_Subtract:    b -= a;       break;
      case OP_Multiply:    b *= a;       break;

        b %= a;
        break;
      }
    }
    POPSTACK;
    Release(p, nos);
    aStack[nos].i = b;
    aStack[nos].flags = STK_Int;
  }else{
    double a, b;
    Realify(p, tos);
    Realify(p, nos);
    a = aStack[tos].r;
    b = aStack[nos].r;
    switch( pOp->opcode ){

        b = ib % ia;
        break;
      }
    }
    POPSTACK;
    Release(p, nos);
    aStack[nos].r = b;
    aStack[nos].flags = STK_Real;
  }
  break;

divide_by_zero:
  sqliteVdbePopStack(p, 2);
  p->tos = nos;
  aStack[nos].flags = STK_Null;
  break;
}

/* Opcode: Function P1 * P3
**
** Invoke a user function (P3 is a pointer to a Function structure that
** defines the function) with P1 string arguments taken from the stack.
** Pop all arguments from the stack and push back the result.
**
** See also: AggFunc
*/
case OP_Function: {
  int n, i;
  sqlite_func ctx;

  n = pOp->p1;
  VERIFY( if( n<0 ) goto bad_instruction; )
  VERIFY( if( p->tos+1<n ) goto not_enough_stack; )
  for(i=p->tos-n+1; i<=p->tos; i++){
    if( aStack[i].flags & STK_Null ){
      zStack[i] = 0;
    }else{
      Stringify(p, i);
    }

  }
  ctx.pFunc = (FuncDef*)pOp->p3;
  ctx.s.flags = STK_Null;
  ctx.z = 0;
  ctx.isError = 0;
  ctx.isStep = 0;
  if( sqliteSafetyOff(db) ) goto abort_due_to_misuse;
  (*ctx.pFunc->xFunc)(&ctx, n, (const char**)&zStack[p->tos-n+1]);
  if( sqliteSafetyOn(db) ) goto abort_due_to_misuse;
  sqliteVdbePopStack(p, n);
  p->tos++;
  aStack[p->tos] = ctx.s;
  if( ctx.s.flags & STK_Dyn ){
    zStack[p->tos] = ctx.z;
  }else if( ctx.s.flags & STK_Str ){
    zStack[p->tos] = aStack[p->tos].z;
  }else{
    zStack[p->tos] = 0;
  }
  if( ctx.isError ){
    sqliteSetString(&p->zErrMsg, 
       zStack[p->tos] ? zStack[p->tos] : "user function error", (char*)0);
    rc = SQLITE_ERROR;
  }
  break;
}

/* Opcode: BitAnd * * *
**

case OP_BitOr:
case OP_ShiftLeft:
case OP_ShiftRight: {
  int tos = p->tos;
  int nos = tos - 1;
  int a, b;
  VERIFY( if( nos<0 ) goto not_enough_stack; )
  if( (aStack[tos].flags | aStack[nos].flags) & STK_Null ){
    POPSTACK;
    Release(p,nos);
    aStack[nos].flags = STK_Null;
    break;
  }
  Integerify(p, tos);
  Integerify(p, nos);
  a = aStack[tos].i;
  b = aStack[nos].i;
  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;
  }
  POPSTACK;
  Release(p, nos);
  aStack[nos].i = a;
  aStack[nos].flags = STK_Int;
  break;
}

/* Opcode: AddImm  P1 * *
** 
** Add the value P1 to whatever is on top of the stack.  The result
** is always an integer.

** current value if P1==0, or to the least integer that is strictly
** greater than its current value if P1==1.
*/
case OP_ForceInt: {
  int tos = p->tos;
  int v;
  VERIFY( if( tos<0 ) goto not_enough_stack; )
  if( (aStack[tos].flags & (STK_Int|STK_Real))==0
         && (zStack[tos]==0 || sqliteIsNumber(zStack[tos])==0) ){
    POPSTACK;
    pc = pOp->p2 - 1;
    break;
  }
  if( aStack[tos].flags & STK_Int ){
    v = aStack[tos].i + (pOp->p1!=0);
  }else{
    Realify(p, tos);
    v = (int)aStack[tos].r;
    if( aStack[tos].r>(double)v ) v++;
    if( pOp->p1 && aStack[tos].r==(double)v ) v++;
  }
  if( aStack[tos].flags & STK_Dyn ) sqliteFree(zStack[tos]);
  zStack[tos] = 0;
  aStack[tos].i = v;
  aStack[tos].flags = STK_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
** with out 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: {
  int tos = p->tos;
  VERIFY( if( tos<0 ) goto not_enough_stack; )
  if( aStack[tos].flags & STK_Int ){
    /* Do nothing */
  }else if( aStack[tos].flags & STK_Real ){
    int i = aStack[tos].r;
    double r = (double)i;
    if( r!=aStack[tos].r ){
      goto mismatch;
    }
    aStack[tos].i = i;
  }else if( aStack[tos].flags & STK_Str ){
    int v;
    if( !toInt(zStack[tos], &v) ){
      double r;
      if( !sqliteIsNumber(zStack[tos]) ){
        goto mismatch;
      }
      Realify(p, tos);
      assert( (aStack[tos].flags & STK_Real)!=0 );
      v = aStack[tos].r;
      r = (double)v;
      if( r!=aStack[tos].r ){
        goto mismatch;
      }
    }
    aStack[tos].i = v;
  }else{
    goto mismatch;
  }
  Release(p, tos);
  aStack[tos].flags = STK_Int;
  break;

mismatch:
  if( pOp->p2==0 ){
    rc = SQLITE_MISMATCH;
    goto abort_due_to_error;
  }else{

  int tos = p->tos;
  int nos = tos - 1;
  int c, v;
  int ft, fn;
  VERIFY( if( nos<0 ) goto not_enough_stack; )
  ft = aStack[tos].flags;
  fn = aStack[nos].flags;
  if( (ft | fn) & STK_Null ){
    POPSTACK;
    POPSTACK;
    if( pOp->p2 ){
      if( pOp->p1 ) pc = pOp->p2-1;
    }else{
      p->tos++;
      aStack[nos].flags = STK_Null;
    }
    break;
  }else if( (ft & fn & STK_Int)==STK_Int ){
    c = aStack[nos].i - aStack[tos].i;
  }else if( (ft & STK_Int)!=0 && (fn & STK_Str)!=0 && toInt(zStack[nos],&v) ){
    Release(p, nos);
    aStack[nos].i = v;
    aStack[nos].flags = STK_Int;
    c = aStack[nos].i - aStack[tos].i;
  }else if( (fn & STK_Int)!=0 && (ft & STK_Str)!=0 && toInt(zStack[tos],&v) ){
    Release(p, tos);
    aStack[tos].i = v;
    aStack[tos].flags = STK_Int;
    c = aStack[nos].i - aStack[tos].i;
  }else{
    Stringify(p, tos);
    Stringify(p, nos);
    c = sqliteCompare(zStack[nos], zStack[tos]);
  }
  switch( pOp->opcode ){
    case OP_Eq:    c = c==0;     break;
    case OP_Ne:    c = c!=0;     break;
    case OP_Lt:    c = c<0;      break;
    case OP_Le:    c = c<=0;     break;
    case OP_Gt:    c = c>0;      break;
    default:       c = c>=0;     break;
  }
  POPSTACK;
  POPSTACK;
  if( pOp->p2 ){
    if( c ) pc = pOp->p2-1;
  }else{
    p->tos++;
    aStack[nos].flags = STK_Int;
    aStack[nos].i = c;
  }
  break;
}
/* INSERT NO CODE HERE!
**
** The opcode numbers are extracted from this source file by doing

case OP_StrLe:
case OP_StrGt:
case OP_StrGe: {
  int tos = p->tos;
  int nos = tos - 1;
  int c;
  VERIFY( if( nos<0 ) goto not_enough_stack; )
  if( (aStack[nos].flags | aStack[tos].flags) & STK_Null ){
    POPSTACK;
    POPSTACK;
    if( pOp->p2 ){
      if( pOp->p1 ) pc = pOp->p2-1;
    }else{
      p->tos++;
      aStack[nos].flags = STK_Null;
    }
    break;
  }else{
    Stringify(p, tos);
    Stringify(p, nos);
    c = strcmp(zStack[nos], zStack[tos]);
  }
  /* The asserts on each case of the following switch are there to verify
  ** that string comparison opcodes are always exactly 6 greater than the
  ** corresponding numeric comparison opcodes.  The code generator depends
  ** on this fact.
  */
  switch( pOp->opcode ){
    case OP_StrEq:    c = c==0;    assert( pOp->opcode-6==OP_Eq );   break;
    case OP_StrNe:    c = c!=0;    assert( pOp->opcode-6==OP_Ne );   break;
    case OP_StrLt:    c = c<0;     assert( pOp->opcode-6==OP_Lt );   break;
    case OP_StrLe:    c = c<=0;    assert( pOp->opcode-6==OP_Le );   break;
    case OP_StrGt:    c = c>0;     assert( pOp->opcode-6==OP_Gt );   break;
    default:          c = c>=0;    assert( pOp->opcode-6==OP_Ge );   break;
  }
  POPSTACK;
  POPSTACK;
  if( pOp->p2 ){
    if( c ) pc = pOp->p2-1;
  }else{
    p->tos++;
    aStack[nos].flags = STK_Int;
    aStack[nos].i = c;
  }
  break;
}

/* Opcode: And * * *
**

case OP_And:
case OP_Or: {
  int tos = p->tos;
  int nos = tos - 1;
  int v1, v2;    /* 0==TRUE, 1==FALSE, 2==UNKNOWN or NULL */

  VERIFY( if( nos<0 ) goto not_enough_stack; )
  if( aStack[tos].flags & STK_Null ){
    v1 = 2;
  }else{
    Integerify(p, tos);
    v1 = aStack[tos].i==0;
  }
  if( aStack[nos].flags & STK_Null ){
    v2 = 2;
  }else{
    Integerify(p, nos);
    v2 = aStack[nos].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;
  Release(p, nos);
  if( v1==2 ){
    aStack[nos].flags = STK_Null;
  }else{
    aStack[nos].i = v1==0;
    aStack[nos].flags = STK_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:
case OP_AbsValue: {
  int tos = p->tos;
  VERIFY( if( tos<0 ) goto not_enough_stack; )
  if( aStack[tos].flags & STK_Real ){
    Release(p, tos);
    if( pOp->opcode==OP_Negative || aStack[tos].r<0.0 ){
      aStack[tos].r = -aStack[tos].r;
    }
    aStack[tos].flags = STK_Real;
  }else if( aStack[tos].flags & STK_Int ){
    Release(p, tos);
    if( pOp->opcode==OP_Negative ||  aStack[tos].i<0 ){
      aStack[tos].i = -aStack[tos].i;
    }
    aStack[tos].flags = STK_Int;
  }else if( aStack[tos].flags & STK_Null ){
    /* Do nothing */
  }else{
    Realify(p, tos);
    Release(p, tos);
    if( pOp->opcode==OP_Negative ||  aStack[tos].r<0.0 ){
      aStack[tos].r = -aStack[tos].r;
    }
    aStack[tos].flags = STK_Real;
  }
  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: {
  int tos = p->tos;
  VERIFY( if( p->tos<0 ) goto not_enough_stack; )
  if( aStack[tos].flags & STK_Null ) break;  /* Do nothing to NULLs */
  Integerify(p, tos);
  Release(p, tos);
  aStack[tos].i = !aStack[tos].i;
  aStack[tos].flags = STK_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: {
  int tos = p->tos;
  VERIFY( if( p->tos<0 ) goto not_enough_stack; )
  if( aStack[tos].flags & STK_Null ) break;  /* Do nothing to NULLs */
  Integerify(p, tos);
  Release(p, tos);
  aStack[tos].i = ~aStack[tos].i;
  aStack[tos].flags = STK_Int;
  break;
}

/* Opcode: Noop * * *
**
** Do nothing.  This instruction is often useful as a jump
** destination.

** 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:
case OP_IfNot: {
  int c;
  VERIFY( if( p->tos<0 ) goto not_enough_stack; )
  if( aStack[p->tos].flags & STK_Null ){
    c = pOp->p1;
  }else{
    Integerify(p, p->tos);
    c = aStack[p->tos].i;
    if( pOp->opcode==OP_IfNot ) c = !c;
  }
  POPSTACK;

*/
case OP_IsNull: {
  int i, cnt;
  cnt = pOp->p1;
  if( cnt<0 ) cnt = -cnt;
  VERIFY( if( p->tos+1-cnt<0 ) goto not_enough_stack; )
  for(i=0; i<cnt; i++){
    if( aStack[p->tos-i].flags & STK_Null ){
      pc = pOp->p2-1;
      break;
    }
  }
  if( pOp->p1>0 ) sqliteVdbePopStack(p, cnt);
  break;
}

/* Opcode: NotNull P1 P2 *
**
** Jump to P2 if the top P1 values on the stack are all not NULL.  Pop the
** stack if P1 times if P1 is greater than zero.  If P1 is less than
** zero then leave the stack unchanged.
*/
case OP_NotNull: {
  int i, cnt;
  cnt = pOp->p1;
  if( cnt<0 ) cnt = -cnt;
  VERIFY( if( p->tos+1-cnt<0 ) goto not_enough_stack; )
  for(i=0; i<cnt && (aStack[p->tos-i].flags & STK_Null)==0; i++){}
  if( i>=cnt ) pc = pOp->p2-1;
  if( pOp->p1>0 ) sqliteVdbePopStack(p, cnt);
  break;
}

/* Opcode: MakeRecord P1 P2 *
**

  ** of data(0).  Idx(k) contains the offset to the start of data(k).
  ** Idx(N) contains the total number of bytes in the record.
  */
  nField = pOp->p1;
  VERIFY( if( p->tos+1<nField ) goto not_enough_stack; )
  nByte = 0;
  for(i=p->tos-nField+1; i<=p->tos; i++){
    if( (aStack[i].flags & STK_Null) ){
      addUnique = pOp->p2;
    }else{
      Stringify(p, i);
      nByte += aStack[i].n;
    }
  }
  if( addUnique ) nByte += sizeof(p->uniqueCnt);

    zNewRecord[j++] = addr & 0xff;
    if( idxWidth>1 ){
      zNewRecord[j++] = (addr>>8)&0xff;
      if( idxWidth>2 ){
        zNewRecord[j++] = (addr>>16)&0xff;
      }
    }
    if( (aStack[i].flags & STK_Null)==0 ){
      addr += aStack[i].n;
    }
  }
  zNewRecord[j++] = addr & 0xff;
  if( idxWidth>1 ){
    zNewRecord[j++] = (addr>>8)&0xff;
    if( idxWidth>2 ){
      zNewRecord[j++] = (addr>>16)&0xff;
    }
  }
  if( addUnique ){
    memcpy(&zNewRecord[j], &p->uniqueCnt, sizeof(p->uniqueCnt));
    p->uniqueCnt++;
    j += sizeof(p->uniqueCnt);
  }
  for(i=p->tos-nField+1; i<=p->tos; i++){
    if( (aStack[i].flags & STK_Null)==0 ){
      memcpy(&zNewRecord[j], zStack[i], aStack[i].n);
      j += aStack[i].n;
    }
  }
  sqliteVdbePopStack(p, nField);
  p->tos++;
  aStack[p->tos].n = nByte;
  if( nByte<=NBFS ){
    assert( zNewRecord==zTemp );
    memcpy(aStack[p->tos].z, zTemp, nByte);
    zStack[p->tos] = aStack[p->tos].z;
    aStack[p->tos].flags = STK_Str;
  }else{
    assert( zNewRecord!=zTemp );
    aStack[p->tos].flags = STK_Str | STK_Dyn;
    zStack[p->tos] = zNewRecord;
  }
  break;
}

/* Opcode: MakeKey P1 P2 P3
**
** Convert the top P1 entries of the stack into a single entry suitable

  nField = pOp->p1;
  VERIFY( if( p->tos+1+addRowid<nField ) goto not_enough_stack; )
  nByte = 0;
  for(j=0, i=p->tos-nField+1; i<=p->tos; i++, j++){
    int flags = aStack[i].flags;
    int len;
    char *z;
    if( flags & STK_Null ){
      nByte += 2;
      containsNull = 1;
    }else if( pOp->p3 && pOp->p3[j]=='t' ){
      Stringify(p, i);
      aStack[i].flags &= ~(STK_Int|STK_Real);
      nByte += aStack[i].n+1;
    }else if( (flags & (STK_Real|STK_Int))!=0 || sqliteIsNumber(zStack[i]) ){
      if( (flags & (STK_Real|STK_Int))==STK_Int ){
        aStack[i].r = aStack[i].i;
      }else if( (flags & (STK_Real|STK_Int))==0 ){
        aStack[i].r = sqliteAtoF(zStack[i]);
      }
      Release(p, i);
      z = aStack[i].z;
      sqliteRealToSortable(aStack[i].r, z);
      len = strlen(z);
      zStack[i] = 0;
      aStack[i].flags = STK_Real;
      aStack[i].n = len+1;
      nByte += aStack[i].n+1;
    }else{
      nByte += aStack[i].n+1;
    }
  }
  if( nByte+sizeof(u32)>MAX_BYTES_PER_ROW ){
    rc = SQLITE_TOOBIG;
    goto abort_due_to_error;
  }
  if( addRowid ) nByte += sizeof(u32);
  if( nByte<=NBFS ){
    zNewKey = zTemp;
  }else{
    zNewKey = sqliteMallocRaw( nByte );
    if( zNewKey==0 ) goto no_mem;
  }
  j = 0;
  for(i=p->tos-nField+1; i<=p->tos; i++){
    if( aStack[i].flags & STK_Null ){
      zNewKey[j++] = 'a';
      zNewKey[j++] = 0;
    }else{
      if( aStack[i].flags & (STK_Int|STK_Real) ){
        zNewKey[j++] = 'b';
      }else{
        zNewKey[j++] = 'c';
      }

      memcpy(&zNewKey[j], zStack[i] ? zStack[i] : aStack[i].z, aStack[i].n);
      j += aStack[i].n;
    }
  }
  if( addRowid ){
    u32 iKey;
    Integerify(p, p->tos-nField);
    iKey = intToKey(aStack[p->tos-nField].i);
    memcpy(&zNewKey[j], &iKey, sizeof(u32));
    sqliteVdbePopStack(p, nField+1);
    if( pOp->p2 && containsNull ) pc = pOp->p2 - 1;
  }else{
    if( pOp->p2==0 ) sqliteVdbePopStack(p, nField+addRowid);
  }
  p->tos++;
  aStack[p->tos].n = nByte;
  if( nByte<=NBFS ){
    assert( zNewKey==zTemp );
    zStack[p->tos] = aStack[p->tos].z;
    memcpy(zStack[p->tos], zTemp, nByte);
    aStack[p->tos].flags = STK_Str;
  }else{
    aStack[p->tos].flags = STK_Str|STK_Dyn;
    zStack[p->tos] = zNewKey;
  }
  break;
}

/* Opcode: IncrKey * * *
**
** The top of the stack should contain an index key generated by
** The MakeKey opcode.  This routine increases the least significant
** byte of that key by one.  This is used so that the MoveTo opcode
** will move to the first entry greater than the key rather than to
** the key itself.
*/
case OP_IncrKey: {
  int tos = p->tos;

  VERIFY( if( tos<0 ) goto bad_instruction );
  Stringify(p, tos);
  if( aStack[tos].flags & (STK_Static|STK_Ephem) ){
    /* CANT HAPPEN.  The IncrKey opcode is only applied to keys
    ** generated by MakeKey or MakeIdxKey and the results of those
    ** operands are always dynamic strings.
    */
    goto abort_due_to_error;
  }
  zStack[tos][aStack[tos].n-1]++;
  break;
}

/* Opcode: Checkpoint P1 * *
**
** Begin a checkpoint.  A checkpoint is the beginning of a operation that
** is part of a larger transaction but which might need to be rolled back

  int i = ++p->tos;
  int aMeta[SQLITE_N_BTREE_META];
  assert( pOp->p2<SQLITE_N_BTREE_META );
  assert( pOp->p1>=0 && pOp->p1<db->nDb );
  assert( db->aDb[pOp->p1].pBt!=0 );
  rc = sqliteBtreeGetMeta(db->aDb[pOp->p1].pBt, aMeta);
  aStack[i].i = aMeta[1+pOp->p2];
  aStack[i].flags = STK_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.

  VERIFY( if( tos<0 ) goto not_enough_stack; )
  assert( i>=0 && i<p->nCursor );
  pC = &p->aCsr[i];
  if( pC->pCursor!=0 ){
    int res, oc;
    pC->nullRow = 0;
    if( aStack[tos].flags & STK_Int ){
      int iKey = intToKey(aStack[tos].i);
      if( pOp->p2==0 && pOp->opcode==OP_MoveTo ){
        pC->movetoTarget = iKey;
        pC->deferredMoveto = 1;
        POPSTACK;
        break;
      }
      sqliteBtreeMoveto(pC->pCursor, (char*)&iKey, sizeof(int), &res);
      pC->lastRecno = aStack[tos].i;
      pC->recnoIsValid = res==0;
    }else{
      Stringify(p, tos);
      sqliteBtreeMoveto(pC->pCursor, zStack[tos], aStack[tos].n, &res);
      pC->recnoIsValid = 0;
    }
    pC->deferredMoveto = 0;
    sqlite_search_count++;
    oc = pOp->opcode;
    if( oc==OP_MoveTo && res<0 ){
      sqliteBtreeNext(pC->pCursor, &res);

  int tos = p->tos;
  int alreadyExists = 0;
  Cursor *pC;
  VERIFY( if( tos<0 ) goto not_enough_stack; )
  if( VERIFY( i>=0 && i<p->nCursor && ) (pC = &p->aCsr[i])->pCursor!=0 ){
    int res, rx;
    Stringify(p, tos);
    rx = sqliteBtreeMoveto(pC->pCursor, zStack[tos], aStack[tos].n, &res);
    alreadyExists = rx==SQLITE_OK && res==0;
    pC->deferredMoveto = 0;
  }
  if( pOp->opcode==OP_Found ){
    if( alreadyExists ) pc = pOp->p2 - 1;
  }else{
    if( !alreadyExists ) pc = pOp->p2 - 1;

    int v;         /* The record number on the P1 entry that matches K */
    char *zKey;    /* The value of K */
    int nKey;      /* Number of bytes in K */

    /* Make sure K is a string and make zKey point to K
    */
    Stringify(p, nos);
    zKey = zStack[nos];
    nKey = aStack[nos].n;
    assert( nKey >= 4 );

    /* 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( p->aCsr[i].deferredMoveto==0 );

    /* The last four bytes of the key are different from R.  Convert the
    ** last four bytes of the key into an integer and push it onto the
    ** stack.  (These bytes are the record number of an entry that
    ** violates a UNIQUE constraint.)
    */
    p->tos++;
    aStack[tos].i = v;
    aStack[tos].flags = STK_Int;
  }
  break;
}

/* Opcode: NotExists P1 P2 *
**
** Use the top of the stack as a integer key.  If a record with that key

case OP_NotExists: {
  int i = pOp->p1;
  int tos = p->tos;
  BtCursor *pCrsr;
  VERIFY( if( tos<0 ) goto not_enough_stack; )
  if( VERIFY( i>=0 && i<p->nCursor && ) (pCrsr = p->aCsr[i].pCursor)!=0 ){
    int res, rx, iKey;
    assert( aStack[tos].flags & STK_Int );
    iKey = intToKey(aStack[tos].i);
    rx = sqliteBtreeMoveto(pCrsr, (char*)&iKey, sizeof(int), &res);
    p->aCsr[i].lastRecno = aStack[tos].i;
    p->aCsr[i].recnoIsValid = res==0;
    p->aCsr[i].nullRow = 0;
    if( rx!=SQLITE_OK || res!=0 ){
      pc = pOp->p2 - 1;

      }
    }
    pC->recnoIsValid = 0;
    pC->deferredMoveto = 0;
  }
  p->tos++;
  aStack[p->tos].i = v;
  aStack[p->tos].flags = STK_Int;
  break;
}

/* Opcode: PutIntKey P1 P2 *
**
** 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

  if( VERIFY( i>=0 && i<p->nCursor && )
      ((pC = &p->aCsr[i])->pCursor!=0 || pC->pseudoTable) ){
    char *zKey;
    int nKey, iKey;
    if( pOp->opcode==OP_PutStrKey ){
      Stringify(p, nos);
      nKey = aStack[nos].n;
      zKey = zStack[nos];
    }else{
      assert( aStack[nos].flags & STK_Int );
      nKey = sizeof(int);
      iKey = intToKey(aStack[nos].i);
      zKey = (char*)&iKey;
      if( pOp->p2 ){
        db->nChange++;
        db->lastRowid = aStack[nos].i;
      }
      if( pC->nextRowidValid && aStack[nos].i>=pC->nextRowid ){
        pC->nextRowidValid = 0;
      }
    }
    if( pC->pseudoTable ){
      /* PutStrKey does not work for pseudo-tables.
      ** The following assert makes sure we are not trying to use
      ** PutStrKey on a pseudo-table
      */
      assert( pOp->opcode==OP_PutIntKey );
      sqliteFree(pC->pData);
      pC->iKey = iKey;
      pC->nData = aStack[tos].n;
      if( aStack[tos].flags & STK_Dyn ){
        pC->pData = zStack[tos];
        zStack[tos] = 0;
        aStack[tos].flags = STK_Null;
      }else{
        pC->pData = sqliteMallocRaw( pC->nData );
        if( pC->pData ){
          memcpy(pC->pData, zStack[tos], pC->nData);
        }
      }
      pC->nullRow = 0;
    }else{
      rc = sqliteBtreeInsert(pC->pCursor, zKey, nKey,
                          zStack[tos], aStack[tos].n);
    }
    pC->recnoIsValid = 0;
    pC->deferredMoveto = 0;
  }
  POPSTACK;
  POPSTACK;
  break;

  int tos = ++p->tos;
  Cursor *pC;
  int n;

  assert( i>=0 && i<p->nCursor );
  pC = &p->aCsr[i];
  if( pC->nullRow ){
    aStack[tos].flags = STK_Null;
  }else if( pC->pCursor!=0 ){
    BtCursor *pCrsr = pC->pCursor;
    sqliteVdbeCursorMoveto(pC);
    if( pC->nullRow ){
      aStack[tos].flags = STK_Null;
      break;
    }else if( pC->keyAsData || pOp->opcode==OP_RowKey ){
      sqliteBtreeKeySize(pCrsr, &n);
    }else{
      sqliteBtreeDataSize(pCrsr, &n);
    }
    aStack[tos].n = n;
    if( n<=NBFS ){
      aStack[tos].flags = STK_Str;
      zStack[tos] = aStack[tos].z;
    }else{
      char *z = sqliteMallocRaw( n );
      if( z==0 ) goto no_mem;
      aStack[tos].flags = STK_Str | STK_Dyn;
      zStack[tos] = z;
    }
    if( pC->keyAsData || pOp->opcode==OP_RowKey ){
      sqliteBtreeKey(pCrsr, 0, n, zStack[tos]);
    }else{
      sqliteBtreeData(pCrsr, 0, n, zStack[tos]);
    }
  }else if( pC->pseudoTable ){
    aStack[tos].n = pC->nData;
    zStack[tos] = pC->pData;
    aStack[tos].flags = STK_Str|STK_Ephem;
  }else{
    aStack[tos].flags = STK_Null;
  }
  break;
}

/* Opcode: Column P1 P2 *
**
** Interpret the data that cursor P1 points to as

  BtCursor *pCrsr;
  int idxWidth;
  unsigned char aHdr[10];

  assert( i<p->nCursor );
  if( i<0 ){
    VERIFY( if( tos+i<0 ) goto bad_instruction; )
    VERIFY( if( (aStack[tos+i].flags & STK_Str)==0 ) goto bad_instruction; )
    zRec = zStack[tos+i];
    payloadSize = aStack[tos+i].n;
  }else if( (pC = &p->aCsr[i])->pCursor!=0 ){
    sqliteVdbeCursorMoveto(pC);
    zRec = 0;
    pCrsr = pC->pCursor;
    if( pC->nullRow ){
      payloadSize = 0;

    payloadSize = 0;
  }

  /* Figure out how many bytes in the column data and where the column
  ** data begins.
  */
  if( payloadSize==0 ){
    aStack[tos].flags = STK_Null;
    p->tos = tos;
    break;
  }else if( payloadSize<256 ){
    idxWidth = 1;
  }else if( payloadSize<65536 ){
    idxWidth = 2;
  }else{

    goto abort_due_to_error;
  }

  /* amt and offset now hold the offset to the start of data and the
  ** amount of data.  Go get the data and put it on the stack.
  */
  if( amt==0 ){
    aStack[tos].flags = STK_Null;
  }else if( zRec ){
    aStack[tos].flags = STK_Str | STK_Ephem;
    aStack[tos].n = amt;
    zStack[tos] = &zRec[offset];
  }else{
    if( amt<=NBFS ){
      aStack[tos].flags = STK_Str;
      zStack[tos] = aStack[tos].z;
      aStack[tos].n = amt;
    }else{
      char *z = sqliteMallocRaw( amt );
      if( z==0 ) goto no_mem;
      aStack[tos].flags = STK_Str | STK_Dyn;
      zStack[tos] = z;
      aStack[tos].n = amt;
    }
    if( pC->keyAsData ){
      sqliteBtreeKey(pCrsr, offset, amt, zStack[tos]);
    }else{
      sqliteBtreeData(pCrsr, offset, amt, zStack[tos]);
    }
  }
  p->tos = tos;
  break;
}

/* Opcode: Recno P1 * *

  pC = &p->aCsr[i];
  sqliteVdbeCursorMoveto(pC);
  if( pC->recnoIsValid ){
    v = pC->lastRecno;
  }else if( pC->pseudoTable ){
    v = keyToInt(pC->iKey);
  }else if( pC->nullRow || pC->pCursor==0 ){
    aStack[tos].flags = STK_Null;
    break;
  }else{
    assert( pC->pCursor!=0 );
    sqliteBtreeKey(pC->pCursor, 0, sizeof(u32), (char*)&v);
    v = keyToInt(v);
  }
  aStack[tos].i = v;
  aStack[tos].flags = STK_Int;
  break;
}

/* Opcode: FullKey P1 * *
**
** Extract the complete key from the record that cursor P1 is currently
** pointing to and push the key onto the stack as a string.

    if( amt<=0 ){
      rc = SQLITE_CORRUPT;
      goto abort_due_to_error;
    }
    if( amt>NBFS ){
      z = sqliteMallocRaw( amt );
      if( z==0 ) goto no_mem;
      aStack[tos].flags = STK_Str | STK_Dyn;
    }else{
      z = aStack[tos].z;
      aStack[tos].flags = STK_Str;
    }
    sqliteBtreeKey(pCrsr, 0, amt, z);
    zStack[tos] = z;
    aStack[tos].n = amt;
  }
  break;
}

/* Opcode: NullRow P1 * *
**

case OP_IdxPut: {
  int i = pOp->p1;
  int tos = p->tos;
  BtCursor *pCrsr;
  VERIFY( if( tos<0 ) goto not_enough_stack; )
  if( VERIFY( i>=0 && i<p->nCursor && ) (pCrsr = p->aCsr[i].pCursor)!=0 ){
    int nKey = aStack[tos].n;
    const char *zKey = zStack[tos];
    if( pOp->p2 ){
      int res, n;
      assert( aStack[tos].n >= 4 );
      rc = sqliteBtreeMoveto(pCrsr, zKey, nKey-4, &res);
      if( rc!=SQLITE_OK ) goto abort_due_to_error;
      while( res!=0 ){
        int c;

case OP_IdxDelete: {
  int i = pOp->p1;
  int tos = p->tos;
  BtCursor *pCrsr;
  VERIFY( if( tos<0 ) goto not_enough_stack; )
  if( VERIFY( i>=0 && i<p->nCursor && ) (pCrsr = p->aCsr[i].pCursor)!=0 ){
    int rx, res;
    rx = sqliteBtreeMoveto(pCrsr, zStack[tos], aStack[tos].n, &res);
    if( rx==SQLITE_OK && res==0 ){
      rc = sqliteBtreeDelete(pCrsr);
    }
    assert( p->aCsr[i].deferredMoveto==0 );
  }
  POPSTACK;
  break;

  if( VERIFY( i>=0 && i<p->nCursor && ) (pCrsr = p->aCsr[i].pCursor)!=0 ){
    int v;
    int sz;
    assert( p->aCsr[i].deferredMoveto==0 );
    sqliteBtreeKeySize(pCrsr, &sz);
    if( sz<sizeof(u32) ){
      aStack[tos].flags = STK_Null;
    }else{
      sqliteBtreeKey(pCrsr, sz - sizeof(u32), sizeof(u32), (char*)&v);
      v = keyToInt(v);
      aStack[tos].i = v;
      aStack[tos].flags = STK_Int;
    }
  }
  break;
}

/* Opcode: IdxGT P1 P2 *
**

  BtCursor *pCrsr;

  if( VERIFY( i>=0 && i<p->nCursor && ) (pCrsr = p->aCsr[i].pCursor)!=0 ){
    int res, rc;
 
    Stringify(p, tos);
    assert( p->aCsr[i].deferredMoveto==0 );
    rc = sqliteBtreeKeyCompare(pCrsr, zStack[tos], aStack[tos].n, 4, &res);
    if( rc!=SQLITE_OK ){
      break;
    }
    if( pOp->opcode==OP_IdxLT ){
      res = -res;
    }else if( pOp->opcode==OP_IdxGE ){
      res++;

case OP_IdxIsNull: {
  int i = pOp->p1;
  int tos = p->tos;
  int k, n;
  const char *z;

  assert( tos>=0 );
  assert( aStack[tos].flags & STK_Str );
  z = zStack[tos];
  n = aStack[tos].n;
  for(k=0; k<n && i>0; i--){
    if( z[k]=='a' ){
      pc = pOp->p2-1;
      break;
    }
    while( k<n && z[k] ){ k++; }

  if( pOp->opcode==OP_CreateTable ){
    rc = sqliteBtreeCreateTable(db->aDb[pOp->p2].pBt, &pgno);
  }else{
    rc = sqliteBtreeCreateIndex(db->aDb[pOp->p2].pBt, &pgno);
  }
  if( rc==SQLITE_OK ){
    aStack[i].i = pgno;
    aStack[i].flags = STK_Int;
    *(u32*)pOp->p3 = pgno;
    pOp->p3 = 0;
  }
  break;
}

/* Opcode: IntegrityCk P1 P2 *

  }
  aRoot[j] = 0;
  sqliteHashClear(&pSet->hash);
  pSet->prev = 0;
  z = sqliteBtreeIntegrityCheck(db->aDb[pOp->p2].pBt, aRoot, nRoot);
  if( z==0 || z[0]==0 ){
    if( z ) sqliteFree(z);
    zStack[tos] = "ok";
    aStack[tos].n = 3;
    aStack[tos].flags = STK_Str | STK_Static;
  }else{
    zStack[tos] = z;
    aStack[tos].n = strlen(z) + 1;
    aStack[tos].flags = STK_Str | STK_Dyn;
  }
  sqliteFree(aRoot);
  break;
}

/* Opcode: ListWrite * * *
**

    VERIFY(
      if( pKeylist->nRead<0 
        || pKeylist->nRead>=pKeylist->nUsed
        || pKeylist->nRead>=pKeylist->nKey ) goto bad_instruction;
    )
    p->tos++;
    aStack[p->tos].i = pKeylist->aKey[pKeylist->nRead++];
    aStack[p->tos].flags = STK_Int;
    zStack[p->tos] = 0;
    if( pKeylist->nRead>=pKeylist->nUsed ){
      p->pList = pKeylist->pNext;
      sqliteFree(pKeylist);
    }
  }else{
    pc = pOp->p2 - 1;
  }

  Sorter *pSorter;
  VERIFY( if( tos<1 ) goto not_enough_stack; )
  if( Dynamicify(p, tos) || Dynamicify(p, nos) ) goto no_mem;
  pSorter = sqliteMallocRaw( sizeof(Sorter) );
  if( pSorter==0 ) goto no_mem;
  pSorter->pNext = p->pSort;
  p->pSort = pSorter;
  assert( aStack[tos].flags & STK_Dyn );
  pSorter->nKey = aStack[tos].n;
  pSorter->zKey = zStack[tos];
  pSorter->nData = aStack[nos].n;
  if( aStack[nos].flags & STK_Dyn ){
    pSorter->pData = zStack[nos];
  }else{
    pSorter->pData = sqliteStrDup(zStack[nos]);
  }
  aStack[tos].flags = 0;
  aStack[nos].flags = 0;
  zStack[tos] = 0;
  zStack[nos] = 0;
  p->tos -= 2;
  break;
}

/* Opcode: SortMakeRec P1 * *
**
** The top P1 elements are the arguments to a callback.  Form these

  int nField;
  int i, j;

  nField = pOp->p1;
  VERIFY( if( p->tos+1<nField ) goto not_enough_stack; )
  nByte = 0;
  for(i=p->tos-nField+1; i<=p->tos; i++){
    if( (aStack[i].flags & STK_Null)==0 ){
      Stringify(p, i);
      nByte += aStack[i].n;
    }
  }
  nByte += sizeof(char*)*(nField+1);
  azArg = sqliteMallocRaw( nByte );
  if( azArg==0 ) goto no_mem;
  z = (char*)&azArg[nField+1];
  for(j=0, i=p->tos-nField+1; i<=p->tos; i++, j++){
    if( aStack[i].flags & STK_Null ){
      azArg[j] = 0;
    }else{
      azArg[j] = z;
      strcpy(z, zStack[i]);
      z += aStack[i].n;
    }
  }
  sqliteVdbePopStack(p, nField);
  p->tos++;
  aStack[p->tos].n = nByte;
  zStack[p->tos] = (char*)azArg;
  aStack[p->tos].flags = STK_Str|STK_Dyn;
  break;
}

/* Opcode: SortMakeKey * * P3
**
** Convert the top few entries of the stack into a sort key.  The
** number of stack entries consumed is the number of characters in 

  int nField;
  int i, j, k;

  nField = strlen(pOp->p3);
  VERIFY( if( p->tos+1<nField ) goto not_enough_stack; )
  nByte = 1;
  for(i=p->tos-nField+1; i<=p->tos; i++){
    if( (aStack[i].flags & STK_Null)!=0 ){
      nByte += 2;
    }else{
      Stringify(p, i);
      nByte += aStack[i].n+2;
    }
  }
  zNewKey = sqliteMallocRaw( nByte );
  if( zNewKey==0 ) goto no_mem;
  j = 0;
  k = 0;
  for(i=p->tos-nField+1; i<=p->tos; i++){
    if( (aStack[i].flags & STK_Null)!=0 ){
      zNewKey[j++] = 'N';
      zNewKey[j++] = 0;
      k++;
    }else{
      zNewKey[j++] = pOp->p3[k++];
      memcpy(&zNewKey[j], zStack[i], aStack[i].n-1);
      j += aStack[i].n-1;
      zNewKey[j++] = 0;
    }
  }
  zNewKey[j] = 0;
  assert( j<nByte );
  sqliteVdbePopStack(p, nField);
  p->tos++;
  aStack[p->tos].n = nByte;
  aStack[p->tos].flags = STK_Str|STK_Dyn;
  zStack[p->tos] = zNewKey;
  break;
}

/* Opcode: Sort * * *
**
** Sort all elements on the sorter.  The algorithm is a
** mergesort.

*/
case OP_SortNext: {
  Sorter *pSorter = p->pSort;
  CHECK_FOR_INTERRUPT;
  if( pSorter!=0 ){
    p->pSort = pSorter->pNext;
    p->tos++;
    zStack[p->tos] = pSorter->pData;
    aStack[p->tos].n = pSorter->nData;
    aStack[p->tos].flags = STK_Str|STK_Dyn;
    sqliteFree(pSorter->zKey);
    sqliteFree(pSorter);
  }else{
    pc = pOp->p2 - 1;
  }
  break;
}

/* Opcode: SortCallback P1 * *
**
** The top of the stack contains a callback record built using
** the SortMakeRec operation with the same P1 value as this
** instruction.  Pop this record from the stack and invoke the
** callback on it.
*/
case OP_SortCallback: {
  int i = p->tos;
  VERIFY( if( i<0 ) goto not_enough_stack; )
  if( p->xCallback==0 ){
    p->pc = pc+1;
    p->azResColumn = (char**)zStack[i];
    p->nResColumn = pOp->p1;
    p->popStack = 1;
    return SQLITE_ROW;
  }else{
    if( sqliteSafetyOff(db) ) goto abort_due_to_misuse;
    if( p->xCallback(p->pCbArg, pOp->p1, (char**)zStack[i], p->azColName)!=0 ){
      rc = SQLITE_ABORT;
    }
    if( sqliteSafetyOn(db) ) goto abort_due_to_misuse;
    p->nCallback++;
  }
  POPSTACK;
  if( sqlite_malloc_failed ) goto no_mem;

    z = p->azField[i];
  }else{
    z = 0;
  }
  p->tos++;
  if( z ){
    aStack[p->tos].n = strlen(z) + 1;
    zStack[p->tos] = z;
    aStack[p->tos].flags = STK_Str;
  }else{
    aStack[p->tos].n = 0;
    zStack[p->tos] = 0;
    aStack[p->tos].flags = STK_Null;
  }
  break;
}

/* Opcode: MemStore P1 P2 *
**
** Write the top of the stack into memory location P1.

    Mem *aMem;
    p->nMem = i + 5;
    aMem = sqliteRealloc(p->aMem, p->nMem*sizeof(p->aMem[0]));
    if( aMem==0 ) goto no_mem;
    if( aMem!=p->aMem ){
      int j;
      for(j=0; j<nOld; j++){
        if( aMem[j].z==p->aMem[j].s.z ){
          aMem[j].z = aMem[j].s.z;
        }
      }
    }
    p->aMem = aMem;
    if( nOld<p->nMem ){
      memset(&p->aMem[nOld], 0, sizeof(p->aMem[0])*(p->nMem-nOld));
    }
  }
  pMem = &p->aMem[i];
  flags = pMem->s.flags;
  if( flags & STK_Dyn ){
    zOld = pMem->z;
  }else{
    zOld = 0;
  }
  pMem->s = aStack[tos];
  flags = pMem->s.flags;
  if( flags & (STK_Static|STK_Dyn|STK_Ephem) ){
    if( (flags & STK_Static)!=0 || (pOp->p2 && (flags & STK_Dyn)!=0) ){
      pMem->z = zStack[tos];
    }else if( flags & STK_Str ){
      pMem->z = sqliteMallocRaw( pMem->s.n );
      if( pMem->z==0 ) goto no_mem;
      memcpy(pMem->z, zStack[tos], pMem->s.n);
      pMem->s.flags |= STK_Dyn;
      pMem->s.flags &= ~(STK_Static|STK_Ephem);
    }
  }else{
    pMem->z = pMem->s.z;
  }
  if( zOld ) sqliteFree(zOld);
  if( pOp->p2 ){
    zStack[tos] = 0;
    aStack[tos].flags = 0;
    POPSTACK;
  }
  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 tos = ++p->tos;
  int i = pOp->p1;
  VERIFY( if( i<0 || i>=p->nMem ) goto bad_instruction; )
  memcpy(&aStack[tos], &p->aMem[i].s, sizeof(aStack[tos])-NBFS);;
  if( aStack[tos].flags & STK_Str ){
    zStack[tos] = p->aMem[i].z;
    aStack[tos].flags |= STK_Ephem;
    aStack[tos].flags &= ~(STK_Dyn|STK_Static);
  }
  break;
}

/* Opcode: MemIncr P1 P2 *
**
** Increment the integer valued memory cell P1 by 1.  If P2 is not zero
** and the result after the increment is greater than zero, then jump
** to P2.
**
** This instruction throws an error if the memory cell is not initially
** an integer.
*/
case OP_MemIncr: {
  int i = pOp->p1;
  Mem *pMem;
  VERIFY( if( i<0 || i>=p->nMem ) goto bad_instruction; )
  pMem = &p->aMem[i];
  VERIFY( if( pMem->s.flags != STK_Int ) goto bad_instruction; )
  pMem->s.i++;
  if( pOp->p2>0 && pMem->s.i>0 ){
     pc = pOp->p2 - 1;
  }
  break;
}

/* Opcode: AggReset * P2 *
**

  int n = pOp->p2;
  int i;
  Mem *pMem;
  sqlite_func ctx;

  VERIFY( if( n<0 ) goto bad_instruction; )
  VERIFY( if( p->tos+1<n ) goto not_enough_stack; )
  VERIFY( if( aStack[p->tos].flags!=STK_Int ) goto bad_instruction; )
  for(i=p->tos-n; i<p->tos; i++){
    if( aStack[i].flags & STK_Null ){
      zStack[i] = 0;
    }else{
      Stringify(p, i);
    }

  }
  i = aStack[p->tos].i;
  VERIFY( if( i<0 || i>=p->agg.nMem ) goto bad_instruction; )
  ctx.pFunc = (FuncDef*)pOp->p3;
  pMem = &p->agg.pCurrent->aMem[i];
  ctx.z = pMem->s.z;
  ctx.pAgg = pMem->z;
  ctx.cnt = ++pMem->s.i;
  ctx.isError = 0;
  ctx.isStep = 1;
  (ctx.pFunc->xStep)(&ctx, n, (const char**)&zStack[p->tos-n]);
  pMem->z = ctx.pAgg;
  pMem->s.flags = STK_AggCtx;
  sqliteVdbePopStack(p, n+1);
  if( ctx.isError ){
    rc = SQLITE_ERROR;
  }
  break;
}

  int tos = p->tos;
  AggElem *pElem;
  char *zKey;
  int nKey;

  VERIFY( if( tos<0 ) goto not_enough_stack; )
  Stringify(p, tos);
  zKey = zStack[tos]; 
  nKey = aStack[tos].n;
  pElem = sqliteHashFind(&p->agg.hash, zKey, nKey);
  if( pElem ){
    p->agg.pCurrent = pElem;
    pc = pOp->p2 - 1;
  }else{
    AggInsert(&p->agg, zKey, nKey);

  int i = pOp->p2;
  int tos = p->tos;
  VERIFY( if( tos<0 ) goto not_enough_stack; )
  if( pFocus==0 ) goto no_mem;
  if( VERIFY( i>=0 && ) i<p->agg.nMem ){
    Mem *pMem = &pFocus->aMem[i];
    char *zOld;
    if( pMem->s.flags & STK_Dyn ){
      zOld = pMem->z;
    }else{
      zOld = 0;
    }
    Deephemeralize(p, tos);
    pMem->s = aStack[tos];
    if( pMem->s.flags & STK_Dyn ){
      pMem->z = zStack[tos];
      zStack[tos] = 0;
      aStack[tos].flags = 0;
    }else if( pMem->s.flags & (STK_Static|STK_AggCtx) ){
      pMem->z = zStack[tos];
    }else if( pMem->s.flags & STK_Str ){
      pMem->z = pMem->s.z;
    }
    if( zOld ) sqliteFree(zOld);
  }
  POPSTACK;
  break;
}

/* Opcode: AggGet * P2 *
**
** Push a new entry onto the stack which is a copy of the P2-th field
** of the current aggregate.  Strings are not duplicated so
** string values will be ephemeral.
*/
case OP_AggGet: {
  AggElem *pFocus = AggInFocus(p->agg);
  int i = pOp->p2;
  int tos = ++p->tos;
  if( pFocus==0 ) goto no_mem;
  if( VERIFY( i>=0 && ) i<p->agg.nMem ){
    Mem *pMem = &pFocus->aMem[i];
    aStack[tos] = pMem->s;
    zStack[tos] = pMem->z;
    aStack[tos].flags &= ~STK_Dyn;
    aStack[tos].flags |= STK_Ephem;
  }
  break;
}

/* Opcode: AggNext * P2 *
**
** Make the next aggregate value the current aggregate.  The prior

    Mem *aMem;
    p->agg.pCurrent = sqliteHashData(p->agg.pSearch);
    aMem = p->agg.pCurrent->aMem;
    for(i=0; i<p->agg.nMem; i++){
      int freeCtx;
      if( p->agg.apFunc[i]==0 ) continue;
      if( p->agg.apFunc[i]->xFinalize==0 ) continue;
      ctx.s.flags = STK_Null;
      ctx.z = 0;
      ctx.pAgg = (void*)aMem[i].z;
      freeCtx = aMem[i].z && aMem[i].z!=aMem[i].s.z;
      ctx.cnt = aMem[i].s.i;
      ctx.isStep = 0;
      ctx.pFunc = p->agg.apFunc[i];
      (*p->agg.apFunc[i]->xFinalize)(&ctx);
      if( freeCtx ){
        sqliteFree( aMem[i].z );
      }
      aMem[i].s = ctx.s;
      aMem[i].z = ctx.z;
      if( (aMem[i].s.flags & STK_Str) &&
              (aMem[i].s.flags & (STK_Dyn|STK_Static|STK_Ephem))==0 ){
        aMem[i].z = aMem[i].s.z;
      }
    }
  }
  break;
}

/* Opcode: SetInsert P1 * P3

  }
  if( pOp->p3 ){
    sqliteHashInsert(&p->aSet[i].hash, pOp->p3, strlen(pOp->p3)+1, p);
  }else{
    int tos = p->tos;
    if( tos<0 ) goto not_enough_stack;
    Stringify(p, tos);
    sqliteHashInsert(&p->aSet[i].hash, zStack[tos], aStack[tos].n, p);
    POPSTACK;
  }
  if( sqlite_malloc_failed ) goto no_mem;
  break;
}

/* Opcode: SetFound P1 P2 *
**
** Pop the stack once and compare the value popped off with the
** contents of set P1.  If the element popped exists in set P1,
** then jump to P2.  Otherwise fall through.
*/
case OP_SetFound: {
  int i = pOp->p1;
  int tos = p->tos;
  VERIFY( if( tos<0 ) goto not_enough_stack; )
  Stringify(p, tos);
  if( i>=0 && i<p->nSet &&
       sqliteHashFind(&p->aSet[i].hash, zStack[tos], aStack[tos].n)){
    pc = pOp->p2 - 1;
  }
  POPSTACK;
  break;
}

/* Opcode: SetNotFound P1 P2 *
**
** Pop the stack once and compare the value popped off with the
** contents of set P1.  If the element popped does not exists in 
** set P1, then jump to P2.  Otherwise fall through.
*/
case OP_SetNotFound: {
  int i = pOp->p1;
  int tos = p->tos;
  VERIFY( if( tos<0 ) goto not_enough_stack; )
  Stringify(p, tos);
  if( i<0 || i>=p->nSet ||
       sqliteHashFind(&p->aSet[i].hash, zStack[tos], aStack[tos].n)==0 ){
    pc = pOp->p2 - 1;
  }
  POPSTACK;
  break;
}

/* Opcode: SetFirst P1 P2 *

    if( pSet->prev==0 ){
      break;
    }else{
      pc = pOp->p2 - 1;
    }
  }
  tos = ++p->tos;
  zStack[tos] = sqliteHashKey(pSet->prev);
  aStack[tos].n = sqliteHashKeysize(pSet->prev);
  aStack[tos].flags = STK_Str | STK_Ephem;
  break;
}

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

      sqliteSetString(&p->zErrMsg, "jump destination out of range", (char*)0);
      rc = SQLITE_INTERNAL;
    }
    if( p->trace && p->tos>=0 ){
      int i;
      fprintf(p->trace, "Stack:");
      for(i=p->tos; i>=0 && i>p->tos-5; i--){
        if( aStack[i].flags & STK_Null ){
          fprintf(p->trace, " NULL");
        }else if( (aStack[i].flags & (STK_Int|STK_Str))==(STK_Int|STK_Str) ){
          fprintf(p->trace, " si:%d", aStack[i].i);
        }else if( aStack[i].flags & STK_Int ){
          fprintf(p->trace, " i:%d", aStack[i].i);
        }else if( aStack[i].flags & STK_Real ){
          fprintf(p->trace, " r:%g", aStack[i].r);
        }else if( aStack[i].flags & STK_Str ){
          int j, k;
          char zBuf[100];
          zBuf[0] = ' ';
          if( aStack[i].flags & STK_Dyn ){
            zBuf[1] = 'z';
            assert( (aStack[i].flags & (STK_Static|STK_Ephem))==0 );
          }else if( aStack[i].flags & STK_Static ){
            zBuf[1] = 't';
            assert( (aStack[i].flags & (STK_Dyn|STK_Ephem))==0 );
          }else if( aStack[i].flags & STK_Ephem ){
            zBuf[1] = 'e';
            assert( (aStack[i].flags & (STK_Static|STK_Dyn))==0 );
          }else{
            zBuf[1] = 's';
          }
          zBuf[2] = '[';
          k = 3;
          for(j=0; j<20 && j<aStack[i].n; j++){
            int c = zStack[i][j];
            if( c==0 && j==aStack[i].n-1 ) break;
            if( isprint(c) && !isspace(c) ){
              zBuf[k++] = c;
            }else{
              zBuf[k++] = '.';
            }
          }

** Number of bytes of string storage space available to each stack
** layer without having to malloc.  NBFS is short for Number of Bytes
** For Strings.
*/
#define NBFS 32

/*
** A single level of the stack is an instance of the following
** structure.  Except, string values are stored on a separate
** list of of pointers to character.  The reason for storing
** strings separately is so that they can be easily passed
** to the callback function.
*/
struct Stack {
  int i;         /* Integer value */
  int n;         /* Number of characters in string value, including '\0' */
  int flags;     /* Some combination of STK_Null, STK_Str, STK_Dyn, etc. */
  double r;      /* Real value */

  char z[NBFS];  /* Space for short strings */
};
typedef struct Stack Stack;

/*
** Memory cells use the same structure as the stack except that space
** for an arbitrary string is added.
*/
struct Mem {
  Stack s;       /* All values of the memory cell besides string */
  char *z;       /* String value for this memory cell */
};
typedef struct Mem Mem;

/*
** Allowed values for Stack.flags
*/
#define STK_Null      0x0001   /* Value is NULL */
#define STK_Str       0x0002   /* Value is a string */
#define STK_Int       0x0004   /* Value is an integer */
#define STK_Real      0x0008   /* Value is a real number */
#define STK_Dyn       0x0010   /* Need to call sqliteFree() on zStack[] */
#define STK_Static    0x0020   /* zStack[] points to a static string */
#define STK_Ephem     0x0040   /* zStack[] points to an ephemeral string */

/* The following STK_ value appears only in AggElem.aMem.s.flag fields.
** It indicates that the corresponding AggElem.aMem.z points to a
** aggregate function context that needs to be finalized.
*/
#define STK_AggCtx    0x0040   /* zStack[] points to an agg function context */

/*
** The "context" argument for a installable function.  A pointer to an
** instance of this structure is the first argument to the routines used
** implement the SQL functions.
**
** There is a typedef for this structure in sqlite.h.  So all routines,
** even the public interface to SQLite, can use a pointer to this structure.
** But this file is the only place where the internal details of this
** structure are known.
**
** This structure is defined inside of vdbe.c because it uses substructures
** (Stack) which are only defined there.
*/
struct sqlite_func {
  FuncDef *pFunc;   /* Pointer to function information.  MUST BE FIRST */
  Stack s;          /* Small strings, ints, and double values go here */
  char *z;          /* Space for holding dynamic string results */
  void *pAgg;       /* Aggregate context */
  u8 isError;       /* Set to true for an error */
  u8 isStep;        /* Current in the step function */
  int cnt;          /* Number of times that the step function has been called */
};

/*

  int nOp;            /* Number of instructions in the program */
  int nOpAlloc;       /* Number of slots allocated for aOp[] */
  Op *aOp;            /* Space to hold the virtual machine's program */
  int nLabel;         /* Number of labels used */
  int nLabelAlloc;    /* Number of slots allocated in aLabel[] */
  int *aLabel;        /* Space to hold the labels */
  int tos;            /* Index of top of stack */
  Stack *aStack;      /* The operand stack, except string values */
  char **zStack;      /* Text or binary values of the stack */
  char **azColName;   /* Becomes the 4th parameter to callbacks */
  int nCursor;        /* Number of slots in aCsr[] */
  Cursor *aCsr;       /* One element of this array for each open cursor */
  Sorter *pSort;      /* A linked list of objects to be sorted */
  FILE *pFile;        /* At most one open file handler */
  int nField;         /* Number of file fields */
  char **azField;     /* Data for each file field */

/*
** Here is a macro to handle the common case of popping the stack
** once.  This macro only works from within the sqliteVdbeExec()
** function.
*/
#define POPSTACK \
  assert(p->tos>=0); \
  if( aStack[p->tos].flags & STK_Dyn ) sqliteFree(zStack[p->tos]); \
  p->tos--;

/*
** Function prototypes
*/
void sqliteVdbeCleanupCursor(Cursor*);
void sqliteVdbeSorterReset(Vdbe*);

**
** These routines are defined here in vdbe.c because they depend on knowing
** the internals of the sqlite_func structure which is only defined in 
** this source file.
*/
char *sqlite_set_result_string(sqlite_func *p, const char *zResult, int n){
  assert( !p->isStep );
  if( p->s.flags & STK_Dyn ){
    sqliteFree(p->z);
  }
  if( zResult==0 ){
    p->s.flags = STK_Null;
    n = 0;
    p->z = 0;
    p->s.n = 0;
  }else{
    if( n<0 ) n = strlen(zResult);
    if( n<NBFS-1 ){
      memcpy(p->s.z, zResult, n);
      p->s.z[n] = 0;
      p->s.flags = STK_Str;
      p->z = p->s.z;
    }else{
      p->z = sqliteMallocRaw( n+1 );
      if( p->z ){
        memcpy(p->z, zResult, n);
        p->z[n] = 0;
      }
      p->s.flags = STK_Str | STK_Dyn;
    }
    p->s.n = n+1;
  }
  return p->z;
}
void sqlite_set_result_int(sqlite_func *p, int iResult){
  assert( !p->isStep );
  if( p->s.flags & STK_Dyn ){
    sqliteFree(p->z);
  }
  p->s.i = iResult;
  p->s.flags = STK_Int;
}
void sqlite_set_result_double(sqlite_func *p, double rResult){
  assert( !p->isStep );
  if( p->s.flags & STK_Dyn ){
    sqliteFree(p->z);
  }
  p->s.r = rResult;
  p->s.flags = STK_Real;
}
void sqlite_set_result_error(sqlite_func *p, const char *zMsg, int n){
  assert( !p->isStep );
  sqlite_set_result_string(p, zMsg, n);
  p->isError = 1;
}

** the internals of the sqlite_func structure which is only defined in
** this source file.
*/
void *sqlite_aggregate_context(sqlite_func *p, int nByte){
  assert( p && p->pFunc && p->pFunc->xStep );
  if( p->pAgg==0 ){
    if( nByte<=NBFS ){
      p->pAgg = (void*)p->z;

    }else{
      p->pAgg = sqliteMalloc( nByte );
    }
  }
  return p->pAgg;
}

     "int",  "text",   "int", "int", "text",
     0
  };

  assert( p->popStack==0 );
  assert( p->explain );
  p->azColName = azColumnNames;
  p->azResColumn = p->zStack;
  for(i=0; i<5; i++) p->zStack[i] = p->aStack[i].z;
  p->rc = SQLITE_OK;
  for(i=p->pc; p->rc==SQLITE_OK && i<p->nOp; i++){
    if( db->flags & SQLITE_Interrupt ){
      db->flags &= ~SQLITE_Interrupt;
      if( db->magic!=SQLITE_MAGIC_BUSY ){
        p->rc = SQLITE_MISUSE;
      }else{
        p->rc = SQLITE_INTERRUPT;
      }
      sqliteSetString(&p->zErrMsg, sqlite_error_string(p->rc), (char*)0);
      break;
    }
    sprintf(p->zStack[0],"%d",i);
    sprintf(p->zStack[2],"%d", p->aOp[i].p1);
    sprintf(p->zStack[3],"%d", p->aOp[i].p2);
    if( p->aOp[i].p3type==P3_POINTER ){
      sprintf(p->aStack[4].z, "ptr(%#x)", (int)p->aOp[i].p3);
      p->zStack[4] = p->aStack[4].z;
    }else{
      p->zStack[4] = p->aOp[i].p3;
    }
    p->zStack[1] = sqliteOpcodeNames[p->aOp[i].opcode];
    if( p->xCallback==0 ){
      p->pc = i+1;
      p->azResColumn = p->zStack;
      p->nResColumn = 5;
      return SQLITE_ROW;
    }
    if( sqliteSafetyOff(db) ){
      p->rc = SQLITE_MISUSE;
      break;
    }
    if( p->xCallback(p->pCbArg, 5, p->zStack, p->azColName) ){
      p->rc = SQLITE_ABORT;
    }
    if( sqliteSafetyOn(db) ){
      p->rc = SQLITE_MISUSE;
    }
  }
  return p->rc==SQLITE_OK ? SQLITE_DONE : SQLITE_ERROR;

  ** Allocation all the stack space we will ever need.
  */
  if( p->aStack==0 ){
    p->nVar = nVar;
    assert( nVar>=0 );
    n = isExplain ? 10 : p->nOp;
    p->aStack = sqliteMalloc(
    n*(sizeof(p->aStack[0]) + 2*sizeof(char*))   /* aStack and zStack */
      + p->nVar*(sizeof(char*)+sizeof(int)+1)      /* azVar, anVar, abVar */
    );
    p->zStack = (char**)&p->aStack[n];
    p->azColName = (char**)&p->zStack[n];
    p->azVar = (char**)&p->azColName[n];
    p->anVar = (int*)&p->azVar[p->nVar];
    p->abVar = (u8*)&p->anVar[p->nVar];
  }

  sqliteHashInit(&p->agg.hash, SQLITE_HASH_BINARY, 0);
  p->agg.pSearch = 0;

/*
** Pop the stack N times.  Free any memory associated with the
** popped stack elements.
*/
void sqliteVdbePopStack(Vdbe *p, int N){
  assert( N>=0 );
  if( p->zStack==0 ) return;
  assert( p->aStack || sqlite_malloc_failed );
  if( p->aStack==0 ) return;
  while( N-- > 0 ){
    if( p->aStack[p->tos].flags & STK_Dyn ){
      sqliteFree(p->zStack[p->tos]);
    }
    p->aStack[p->tos].flags = 0;
    p->zStack[p->tos] = 0;
    p->tos--;
  }
}

/*
** Reset an Agg structure.  Delete all its contents. 
**

  int i;
  HashElem *p;
  for(p = sqliteHashFirst(&pAgg->hash); p; p = sqliteHashNext(p)){
    AggElem *pElem = sqliteHashData(p);
    assert( pAgg->apFunc!=0 );
    for(i=0; i<pAgg->nMem; i++){
      Mem *pMem = &pElem->aMem[i];
      if( pAgg->apFunc[i] && (pMem->s.flags & STK_AggCtx)!=0 ){
        sqlite_func ctx;
        ctx.pFunc = pAgg->apFunc[i];
        ctx.s.flags = STK_Null;
        ctx.z = 0;
        ctx.pAgg = pMem->z;
        ctx.cnt = pMem->s.i;
        ctx.isStep = 0;
        ctx.isError = 0;
        (*pAgg->apFunc[i]->xFinalize)(&ctx);
        if( pMem->z!=0 && pMem->z!=pMem->s.z ){
          sqliteFree(pMem->z);
        }
      }else if( pMem->s.flags & STK_Dyn ){
        sqliteFree(pMem->z);
      }
    }
    sqliteFree(pElem);
  }
  sqliteHashClear(&pAgg->hash);
  sqliteFree(pAgg->apFunc);

*/
static void Cleanup(Vdbe *p){
  int i;
  sqliteVdbePopStack(p, p->tos+1);
  closeAllCursors(p);
  if( p->aMem ){
    for(i=0; i<p->nMem; i++){
      if( p->aMem[i].s.flags & STK_Dyn ){
        sqliteFree(p->aMem[i].z);
      }
    }
  }
  sqliteFree(p->aMem);
  p->aMem = 0;
  p->nMem = 0;