SQLite

  ** that the object will never already be in cache.  Verify this guarantee.
  */
#ifndef NDEBUG
  for(i=0, p=pParse->aColCache; i<pParse->nColCache; i++, p++){
    assert( p->iTable!=iTab || p->iColumn!=iCol );
  }
#endif

#ifdef SQLITE_DEBUG_COLUMNCACHE
  /* Add a SetTabCol opcode for run-time verification that the column
  ** cache is working correctly.
  */
  sqlite3VdbeAddOp3(pParse->pVdbe, OP_SetTabCol, iTab, iCol, iReg);
#endif

  /* If the cache is already full, delete the least recently used entry */
  if( pParse->nColCache>=SQLITE_N_COLCACHE ){
    minLru = 0x7fffffff;
    idxLru = -1;
    for(i=0, p=pParse->aColCache; i<SQLITE_N_COLCACHE; i++, p++){
      if( p->lru<minLru ){

  int i;
  struct yColCache *p;

  for(i=0, p=pParse->aColCache; i<pParse->nColCache; i++, p++){
    if( p->iTable==iTable && p->iColumn==iColumn ){
      p->lru = pParse->iCacheCnt++;
      sqlite3ExprCachePinRegister(pParse, p->iReg);
#ifdef SQLITE_DEBUG_COLUMNCACHE
      sqlite3VdbeAddOp3(v, OP_VerifyTabCol, iTable, iColumn, p->iReg);
#endif
      return p->iReg;
    }
  }  
  assert( v!=0 );
  sqlite3ExprCodeGetColumnOfTable(v, pTab, iTable, iColumn, iReg);
  if( p5 ){
    sqlite3VdbeChangeP5(v, p5);

*/
#if !defined(NDEBUG) && !defined(SQLITE_DEBUG)
# define NDEBUG 1
#endif
#if defined(NDEBUG) && defined(SQLITE_DEBUG)
# undef NDEBUG
#endif

/* SQLITE_DEBUG_COLUMNCACHE is synomous with SQLITE_DEBUG.  The 
** SQLITE_DEBUG_COLUMNCACHE symbol only exists to provide a convenient
** way to search for all code that deals with verifying correct behavior
** of the column cache.
*/
#ifdef SQLITE_DEBUG
# define SQLITE_DEBUG_COLUMNCACHE 1
#else
# undef SQLIT_DEBUG_COLUMNCACHE
#endif

/*
** Enable SQLITE_ENABLE_EXPLAIN_COMMENTS if SQLITE_DEBUG is turned on.
*/
#if !defined(SQLITE_ENABLE_EXPLAIN_COMMENTS) && defined(SQLITE_DEBUG)
# define SQLITE_ENABLE_EXPLAIN_COMMENTS 1
#endif

*/
#ifdef SQLITE_DEBUG
# define memAboutToChange(P,M) sqlite3VdbeMemAboutToChange(P,M)
#else
# define memAboutToChange(P,M)
#endif

/*
** Given a cursor number and a column for a table or index, compute a
** hash value for use in the Mem.iTabColHash value.  The iTabColHash
** column is only used for verification - it is omitted from production
** builds.  Collisions are harmless in the sense that the correct answer
** still results.  The only harm of collisions is that they can potential
** reduce column-cache error detection during SQLITE_DEBUG builds.
**
** No valid hash should be 0.
*/
#define TableColumnHash(T,C)  (((u32)(T)<<16)^(u32)(C+2))

/*
** The following global variable is incremented every time a cursor
** moves, either by the OP_SeekXX, 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.
*/

** an active statement journal.
*/
case OP_Abortable: {
  sqlite3VdbeAssertAbortable(p);
  break;
}
#endif

#ifdef SQLITE_DEBUG_COLUMNCACHE
/* Opcode:  SetTabCol   P1 P2 P3 * *
**
** Set a flag in register REG[P3] indicating that it holds the value
** of column P2 from the table on cursor P1.  This flag is checked
** by a subsequent VerifyTabCol opcode.
**
** This opcode only appears SQLITE_DEBUG builds.  It is used to verify
** that the expression table column cache is working correctly.
*/
case OP_SetTabCol: {
  aMem[pOp->p3].iTabColHash = TableColumnHash(pOp->p1,pOp->p2);
  break;
}
/* Opcode:  VerifyTabCol   P1 P2 P3 * *
**
** Verify that register REG[P3] contains the value of column P2 from
** cursor P1.  Assert() if this is not the case.
**
** This opcode only appears SQLITE_DEBUG builds.  It is used to verify
** that the expression table column cache is working correctly.
*/
case OP_VerifyTabCol: {
  assert( aMem[pOp->p3].iTabColHash == TableColumnHash(pOp->p1,pOp->p2) );
  break;
}
#endif

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

#endif

#ifdef SQLITE_ENABLE_STMT_SCANSTATUS
void sqlite3VdbeScanStatus(Vdbe*, int, int, int, LogEst, const char*);
#else
# define sqlite3VdbeScanStatus(a,b,c,d,e)
#endif

#if defined(SQLITE_DEBUG) || defined(VDBE_PROFILE)
void sqlite3VdbePrintOp(FILE*, int, VdbeOp*);
#endif

#endif /* SQLITE_VDBE_H */

  u32 uTemp;          /* Transient storage for serial_type in OP_MakeRecord */
  sqlite3 *db;        /* The associated database connection */
  void (*xDel)(void*);/* Destructor for Mem.z - only valid if MEM_Dyn */
#ifdef SQLITE_DEBUG
  Mem *pScopyFrom;    /* This Mem is a shallow copy of pScopyFrom */
  void *pFiller;      /* So that sizeof(Mem) is a multiple of 8 */
#endif
#ifdef SQLITE_DEBUG_COLUMNCACHE
  u32 iTabColHash;    /* Hash of table.column that is origin of this value */
#endif
};

/*
** Size of struct Mem not including the Mem.zMalloc member or anything that
** follows.
*/
#define MEMCELLSIZE offsetof(Mem,zMalloc)

** Function prototypes
*/
void sqlite3VdbeError(Vdbe*, const char *, ...);
void sqlite3VdbeFreeCursor(Vdbe *, VdbeCursor*);
void sqliteVdbePopStack(Vdbe*,int);
int sqlite3VdbeCursorMoveto(VdbeCursor**, int*);
int sqlite3VdbeCursorRestore(VdbeCursor*);



u32 sqlite3VdbeSerialTypeLen(u32);
u8 sqlite3VdbeOneByteSerialTypeLen(u8);
u32 sqlite3VdbeSerialType(Mem*, int, u32*);
u32 sqlite3VdbeSerialPut(unsigned char*, Mem*, u32);
u32 sqlite3VdbeSerialGet(const unsigned char*, u32, Mem*);
void sqlite3VdbeDeleteAuxData(sqlite3*, AuxData**, int, int);

}
#endif

#if defined(VDBE_PROFILE) || defined(SQLITE_DEBUG)
/*
** Print a single opcode.  This routine is used for debugging only.
*/
void sqlite3VdbePrintOp(FILE *pOut, int pc, VdbeOp *pOp){
  char *zP4;
  char zPtr[50];
  char zCom[100];
  static const char *zFormat1 = "%4d %-13s %4d %4d %4d %-13s %.2X %s\n";
  if( pOut==0 ) pOut = stdout;
  zP4 = displayP4(pOp, zPtr, sizeof(zPtr));
#ifdef SQLITE_ENABLE_EXPLAIN_COMMENTS

      /* pMem is the register that is changing.  But also mark pX as
      ** undefined so that we can quickly detect the shallow-copy error */
      pX->flags = MEM_Undefined;
      pX->pScopyFrom = 0;
    }
  }
  pMem->pScopyFrom = 0;
#ifdef SQLITE_DEBUG_COLUMN_CACHE
  pMem->iTabColHash = 0;
#endif
}
#endif /* SQLITE_DEBUG */


/*
** Make an shallow copy of pFrom into pTo.  Prior contents of
** pTo are freed.  The pFrom->z field is not duplicated.  If
** pFrom->z is used, then pTo->z points to the same thing as pFrom->z
** and flags gets srcType (either MEM_Ephem or MEM_Static).
*/
static SQLITE_NOINLINE void vdbeClrCopy(Mem *pTo, const Mem *pFrom, int eType){
  vdbeMemClearExternAndSetNull(pTo);
  assert( !VdbeMemDynamic(pTo) );
  sqlite3VdbeMemShallowCopy(pTo, pFrom, eType);
}
void sqlite3VdbeMemShallowCopy(Mem *pTo, const Mem *pFrom, int srcType){
  assert( (pFrom->flags & MEM_RowSet)==0 );
  assert( pTo->db==pFrom->db );
  if( VdbeMemDynamic(pTo) ){ vdbeClrCopy(pTo,pFrom,srcType); return; }
  memcpy(pTo, pFrom, MEMCELLSIZE);
#ifdef SQLITE_DEBUG_COLUMNCACHE
  pTo->iTabColHash = pFrom->iTabColHash;
#endif
  if( (pFrom->flags&MEM_Static)==0 ){
    pTo->flags &= ~(MEM_Dyn|MEM_Static|MEM_Ephem);
    assert( srcType==MEM_Ephem || srcType==MEM_Static );
    pTo->flags |= srcType;
  }
}

/*
** Make a full copy of pFrom into pTo.  Prior contents of pTo are
** freed before the copy is made.
*/
int sqlite3VdbeMemCopy(Mem *pTo, const Mem *pFrom){
  int rc = SQLITE_OK;

  assert( (pFrom->flags & MEM_RowSet)==0 );
  if( VdbeMemDynamic(pTo) ) vdbeMemClearExternAndSetNull(pTo);
  memcpy(pTo, pFrom, MEMCELLSIZE);
#ifdef SQLITE_DEBUG_COLUMNCACHE
  pTo->iTabColHash = pFrom->iTabColHash;
#endif
  pTo->flags &= ~MEM_Dyn;
  if( pTo->flags&(MEM_Str|MEM_Blob) ){
    if( 0==(pFrom->flags&MEM_Static) ){
      pTo->flags |= MEM_Ephem;
      rc = sqlite3VdbeMemMakeWriteable(pTo);
    }
  }

  if( pWInfo ){
    pParse->nQueryLoop = pWInfo->savedNQueryLoop;
    whereInfoFree(db, pWInfo);
  }
  return 0;
}

/*
** Part of sqlite3WhereEnd() will rewrite opcodes to reference the
** index rather than the main table.  In SQLITE_DEBUG mode, we want
** to trace those changes if PRAGMA vdbe_addoptrace=on.  This routine
** does that.
*/
#ifndef SQLITE_DEBUG
# define OpcodeRewriteTrace(D,K,P) /* no-op */
#else
# define OpcodeRewriteTrace(D,K,P) sqlite3WhereOpcodeRewriteTrace(D,K,P)
  static void sqlite3WhereOpcodeRewriteTrace(
    sqlite3 *db,
    int pc,
    VdbeOp *pOp
  ){
    if( (db->flags & SQLITE_VdbeAddopTrace)==0 ) return;
    sqlite3VdbePrintOp(0, pc, pOp);
  }
#endif

/*
** Generate the end of the WHERE loop.  See comments on 
** sqlite3WhereBegin() for additional information.
*/
void sqlite3WhereEnd(WhereInfo *pWInfo){
  Parse *pParse = pWInfo->pParse;
  Vdbe *v = pParse->pVdbe;

    }
    if( pIdx
     && (pWInfo->eOnePass==ONEPASS_OFF || !HasRowid(pIdx->pTable))
     && !db->mallocFailed
    ){
      last = sqlite3VdbeCurrentAddr(v);
      k = pLevel->addrBody;
#ifdef SQLITE_DEBUG
      if( db->flags & SQLITE_VdbeAddopTrace ){
        printf("TRANSLATE opcodes in range %d..%d\n", k, last-1);
      }
#endif
      pOp = sqlite3VdbeGetOp(v, k);
      for(; k<last; k++, pOp++){
        if( pOp->p1!=pLevel->iTabCur ) continue;
        if( pOp->opcode==OP_Column
#ifdef SQLITE_ENABLE_OFFSET_SQL_FUNC
         || pOp->opcode==OP_Offset
#endif
        ){
          int x = pOp->p2;
          assert( pIdx->pTable==pTab );
          if( !HasRowid(pTab) ){
            Index *pPk = sqlite3PrimaryKeyIndex(pTab);
            x = pPk->aiColumn[x];
            assert( x>=0 );
          }
          x = sqlite3ColumnOfIndex(pIdx, x);
          if( x>=0 ){
            pOp->p2 = x;
            pOp->p1 = pLevel->iIdxCur;
            OpcodeRewriteTrace(db, k, pOp);
          }
          assert( (pLoop->wsFlags & WHERE_IDX_ONLY)==0 || x>=0 
              || pWInfo->eOnePass );
        }else if( pOp->opcode==OP_Rowid ){
          pOp->p1 = pLevel->iIdxCur;
          pOp->opcode = OP_IdxRowid;
          OpcodeRewriteTrace(db, k, pOp);
        }else if( pOp->opcode==OP_IfNullRow ){
          pOp->p1 = pLevel->iIdxCur;
          OpcodeRewriteTrace(db, k, pOp);
        }
      }
#ifdef SQLITE_DEBUG
      if( db->flags & SQLITE_VdbeAddopTrace ) printf("TRANSLATE complete\n");
#endif
    }
  }

  /* Final cleanup
  */
  pParse->nQueryLoop = pWInfo->savedNQueryLoop;
  whereInfoFree(db, pWInfo);
  return;
}