** inplicit conversion from one type to the other occurs as necessary.
** 
** Most of the code in this file is taken up by the sqliteVdbeExec()
** 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.
**
** $Id: vdbe.c,v 1.44 2000/10/19 01:49:03 drh Exp $
*/
#include "sqliteInt.h"
#include <unistd.h>
#include <ctype.h>

/*
** SQL is translated into a sequence of instructions to be
................................................................................
** already.  Return non-zero if we run out of memory.
**
** NULLs are converted into an empty string.
*/
#define Stringify(P,I) \
   ((P->aStack[I].flags & STK_Str)==0 ? hardStringify(P,I) : 0)
static int hardStringify(Vdbe *p, int i){


  char zBuf[30];
  int fg = p->aStack[i].flags;
  if( fg & STK_Real ){
    sprintf(zBuf,"%.15g",p->aStack[i].r);
  }else if( fg & STK_Int ){
    sprintf(zBuf,"%d",p->aStack[i].i);
  }else{
    p->zStack[i] = "";
    p->aStack[i].n = 1;

    p->aStack[i].flags |= STK_Str;
    return 0;
  }
  p->zStack[i] = sqliteStrDup(zBuf);
  if( p->zStack[i]==0 ) return 1;
  p->aStack[i].n = strlen(p->zStack[i])+1;

  p->aStack[i].flags |= STK_Str|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); }
................................................................................
}

/*
** Pop the stack N times.  Free any memory associated with the
** popped stack elements.
*/
static void PopStack(Vdbe *p, int N){


  if( p->zStack==0 ) return;













  while( p->tos>=0 && N-->0 ){
    int i = p->tos--;
    if( p->aStack[i].flags & STK_Dyn ){
      sqliteFree(p->zStack[i]);
    }
    p->aStack[i].flags = 0;
    p->zStack[i] = 0;
  }    

}

/*
** Make sure space has been allocated to hold at least N
** stack elements.  Allocate additional stack space if
** necessary.
**

** inplicit conversion from one type to the other occurs as necessary.
** 
** Most of the code in this file is taken up by the sqliteVdbeExec()
** 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.
**
** $Id: vdbe.c,v 1.45 2000/10/19 14:42:05 drh Exp $
*/
#include "sqliteInt.h"
#include <unistd.h>
#include <ctype.h>

/*
** SQL is translated into a sequence of instructions to be
................................................................................
** already.  Return non-zero if we run out of memory.
**
** NULLs are converted into an empty string.
*/
#define Stringify(P,I) \
   ((P->aStack[I].flags & STK_Str)==0 ? hardStringify(P,I) : 0)
static int hardStringify(Vdbe *p, int i){
  Stack *pStack = &p->aStack[i];
  char **pzStack = &p->zStack[i];
  char zBuf[30];
  int fg = pStack->flags;
  if( fg & STK_Real ){
    sprintf(zBuf,"%.15g",pStack->r);
  }else if( fg & STK_Int ){
    sprintf(zBuf,"%d",pStack->i);
  }else{
    p->zStack[i] = "";

    pStack->n = 1;
    pStack->flags |= STK_Str;
    return 0;
  }
  *pzStack = sqliteStrDup(zBuf);
  if( *pzStack==0 ) return 1;

  pStack->n = strlen(*pzStack)+1;
  pStack->flags |= STK_Str|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); }
................................................................................
}

/*
** Pop the stack N times.  Free any memory associated with the
** popped stack elements.
*/
static void PopStack(Vdbe *p, int N){
  char **pzStack;
  Stack *pStack;
  if( p->zStack==0 ) return;
  pStack = &p->aStack[p->tos];
  pzStack = &p->zStack[p->tos];
  p->tos -= N;
  while( N-- > 0 ){
    if( pStack->flags & STK_Dyn ){
      sqliteFree(*pzStack);
    }
    pStack->flags = 0;
    *pzStack = 0;
    pStack--;
    pzStack--;
  }
#if 0  /* Older code was a little slower */
  while( p->tos>=0 && N-->0 ){
    int i = p->tos--;
    if( p->aStack[i].flags & STK_Dyn ){
      sqliteFree(p->zStack[i]);
    }
    p->aStack[i].flags = 0;
    p->zStack[i] = 0;
  }
#endif  
}

/*
** Make sure space has been allocated to hold at least N
** stack elements.  Allocate additional stack space if
** necessary.
**