**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains code used to implement the ATTACH and DETACH commands.
**
** $Id: attach.c,v 1.67 2008/01/09 23:04:12 drh Exp $
*/
#include "sqliteInt.h"

#ifndef SQLITE_OMIT_ATTACH
/*
** Resolve an expression that was part of an ATTACH or DETACH statement. This
** is slightly different from resolving a normal SQL expression, because simple
................................................................................
  Expr *pKey           /* Database key for encryption extension */
){
  int rc;
  NameContext sName;
  Vdbe *v;
  FuncDef *pFunc;
  sqlite3* db = pParse->db;


#ifndef SQLITE_OMIT_AUTHORIZATION
  assert( db->mallocFailed || pAuthArg );
  if( pAuthArg ){
    char *zAuthArg = sqlite3NameFromToken(db, &pAuthArg->span);
    if( !zAuthArg ){
      goto attach_end;
................................................................................
      SQLITE_OK!=(rc = resolveAttachExpr(&sName, pKey))
  ){
    pParse->nErr++;
    goto attach_end;
  }

  v = sqlite3GetVdbe(pParse);

  sqlite3ExprCode(pParse, pFilename, 0);
  sqlite3ExprCode(pParse, pDbname, 0);
  sqlite3ExprCode(pParse, pKey, 0);

  assert( v || db->mallocFailed );
  if( v ){
    sqlite3VdbeAddOp0(v, OP_Function);
    sqlite3VdbeChangeP5(v, nFunc);
    pFunc = sqlite3FindFunction(db, zFunc, strlen(zFunc), nFunc, SQLITE_UTF8,0);
    sqlite3VdbeChangeP4(v, -1, (char *)pFunc, P4_FUNCDEF);

    /* Code an OP_Expire. For an ATTACH statement, set P1 to true (expire this
    ** statement only). For DETACH, set it to false (expire all existing
    ** statements).

**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains code used to implement the ATTACH and DETACH commands.
**
** $Id: attach.c,v 1.68 2008/01/12 19:03:49 drh Exp $
*/
#include "sqliteInt.h"

#ifndef SQLITE_OMIT_ATTACH
/*
** Resolve an expression that was part of an ATTACH or DETACH statement. This
** is slightly different from resolving a normal SQL expression, because simple
................................................................................
  Expr *pKey           /* Database key for encryption extension */
){
  int rc;
  NameContext sName;
  Vdbe *v;
  FuncDef *pFunc;
  sqlite3* db = pParse->db;
  int regArgs;

#ifndef SQLITE_OMIT_AUTHORIZATION
  assert( db->mallocFailed || pAuthArg );
  if( pAuthArg ){
    char *zAuthArg = sqlite3NameFromToken(db, &pAuthArg->span);
    if( !zAuthArg ){
      goto attach_end;
................................................................................
      SQLITE_OK!=(rc = resolveAttachExpr(&sName, pKey))
  ){
    pParse->nErr++;
    goto attach_end;
  }

  v = sqlite3GetVdbe(pParse);
  regArgs = sqlite3GetTempRange(pParse, nFunc);
  sqlite3ExprCode(pParse, pFilename, regArgs);
  sqlite3ExprCode(pParse, pDbname, regArgs+1);
  sqlite3ExprCode(pParse, pKey, regArgs+2);

  assert( v || db->mallocFailed );
  if( v ){
    sqlite3VdbeAddOp3(v, OP_Function, 0, regArgs+3-nFunc, regArgs);
    sqlite3VdbeChangeP5(v, nFunc);
    pFunc = sqlite3FindFunction(db, zFunc, strlen(zFunc), nFunc, SQLITE_UTF8,0);
    sqlite3VdbeChangeP4(v, -1, (char *)pFunc, P4_FUNCDEF);

    /* Code an OP_Expire. For an ATTACH statement, set P1 to true (expire this
    ** statement only). For DETACH, set it to false (expire all existing
    ** statements).

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains routines used for analyzing expressions and
** for generating VDBE code that evaluates expressions in SQLite.
**
** $Id: expr.c,v 1.343 2008/01/12 12:48:08 drh Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>

/*
** Return the 'affinity' of the expression pExpr if any.
**
................................................................................
    }
#endif
  }
}

/*
** Generate code into the current Vdbe to evaluate the given
** expression and leaves the result in a register on on the stack.
**
** If the target register number is negative, allocate a new
** register to store the result.  If the target register number
** is zero then push the result onto the stack.  Return the target
** register number regardless.
**
** This code depends on the fact that certain token values (ex: TK_EQ)
** are the same as opcode values (ex: OP_Eq) that implement the corresponding
** operation.  Special comments in vdbe.c and the mkopcodeh.awk script in
** the make process cause these values to align.  Assert()s in the code
** below verify that the numbers are aligned correctly.
*/
int sqlite3ExprCode(Parse *pParse, Expr *pExpr, int target){
  Vdbe *v = pParse->pVdbe;
  int op;
  int inReg = 0;
  int origTarget = target;

  assert( v!=0 || pParse->db->mallocFailed );
  if( v==0 ) return 0;
  if( target<0 ){
    target = ++pParse->nMem;
  }

  if( pExpr==0 ){
    op = TK_NULL;
  }else{
    op = pExpr->op;
  }
  switch( op ){
................................................................................
      if( !pAggInfo->directMode ){
        assert( pCol->iMem>0 );
        inReg = pCol->iMem;
        break;
      }else if( pAggInfo->useSortingIdx ){
        sqlite3VdbeAddOp3(v, OP_Column, pAggInfo->sortingIdx,
                              pCol->iSorterColumn, target);
        inReg = target;
        break;
      }
      /* Otherwise, fall thru into the TK_COLUMN case */
    }
    case TK_COLUMN: {
      if( pExpr->iTable<0 ){
        /* This only happens when coding check constraints */
        assert( pParse->ckBase>0 );
        inReg = pExpr->iColumn + pParse->ckBase;
      }else{
        sqlite3ExprCodeGetColumn(v, pExpr->pTab,
                                 pExpr->iColumn, pExpr->iTable, target);
        inReg = target;
      }
      break;
    }
    case TK_INTEGER: {
      codeInteger(v, (char*)pExpr->token.z, pExpr->token.n, 0, target);
      inReg = target;
      break;
    }
    case TK_FLOAT: {
      codeReal(v, (char*)pExpr->token.z, pExpr->token.n, 0, target);
      inReg = target;
      break;
    }
    case TK_STRING: {
      sqlite3DequoteExpr(pParse->db, pExpr);
      sqlite3VdbeAddOp4(v,OP_String8, 0, target, 0,
                        (char*)pExpr->token.z, pExpr->token.n);
      inReg = target;
      break;
    }
    case TK_NULL: {
      sqlite3VdbeAddOp2(v, OP_Null, 0, target);
      inReg = target;
      break;
    }
#ifndef SQLITE_OMIT_BLOB_LITERAL
    case TK_BLOB: {
      int n;
      const char *z;
      assert( TK_BLOB==OP_HexBlob );
................................................................................
      n = pExpr->token.n - 3;
      z = (char*)pExpr->token.z + 2;
      assert( n>=0 );
      if( n==0 ){
        z = "";
      }
      sqlite3VdbeAddOp4(v, op, 0, target, 0, z, n);
      inReg = target;
      break;
    }
#endif
    case TK_VARIABLE: {
      sqlite3VdbeAddOp2(v, OP_Variable, pExpr->iTable, target);
      if( pExpr->token.n>1 ){
        sqlite3VdbeChangeP4(v, -1, (char*)pExpr->token.z, pExpr->token.n);
      }
      inReg = target;
      break;
    }
    case TK_REGISTER: {
      inReg = pExpr->iTable;
      break;
    }
#ifndef SQLITE_OMIT_CAST
    case TK_CAST: {
      /* Expressions of the form:   CAST(pLeft AS token) */
      int aff, to_op;
      sqlite3ExprCode(pParse, pExpr->pLeft, target);
      aff = sqlite3AffinityType(&pExpr->token);
      to_op = aff - SQLITE_AFF_TEXT + OP_ToText;
      assert( to_op==OP_ToText    || aff!=SQLITE_AFF_TEXT    );
      assert( to_op==OP_ToBlob    || aff!=SQLITE_AFF_NONE    );
      assert( to_op==OP_ToNumeric || aff!=SQLITE_AFF_NUMERIC );
      assert( to_op==OP_ToInt     || aff!=SQLITE_AFF_INTEGER );
      assert( to_op==OP_ToReal    || aff!=SQLITE_AFF_REAL    );
      sqlite3VdbeAddOp1(v, to_op, target);
      inReg = target;
      break;
    }
#endif /* SQLITE_OMIT_CAST */
    case TK_LT:
    case TK_LE:
    case TK_GT:
    case TK_GE:
    case TK_NE:
    case TK_EQ: {
      int r1, r2;
      assert( TK_LT==OP_Lt );
      assert( TK_LE==OP_Le );
      assert( TK_GT==OP_Gt );
      assert( TK_GE==OP_Ge );
      assert( TK_EQ==OP_Eq );
      assert( TK_NE==OP_Ne );
      if( target>0 ){
        inReg = target;
      }else{
        inReg = ++pParse->nMem;
      }
      r1 = sqlite3ExprCode(pParse, pExpr->pLeft, -1);
      r2 = sqlite3ExprCode(pParse, pExpr->pRight, -1);
      codeCompare(pParse, pExpr->pLeft, pExpr->pRight, op,
                  r1, r2, inReg, SQLITE_STOREP2);
      break;
    }
    case TK_AND:
    case TK_OR:
    case TK_PLUS:
................................................................................
    case TK_REM:
    case TK_BITAND:
    case TK_BITOR:
    case TK_SLASH:
    case TK_LSHIFT:
    case TK_RSHIFT: 
    case TK_CONCAT: {
      int r1, r2;
      assert( TK_AND==OP_And );
      assert( TK_OR==OP_Or );
      assert( TK_PLUS==OP_Add );
      assert( TK_MINUS==OP_Subtract );
      assert( TK_REM==OP_Remainder );
      assert( TK_BITAND==OP_BitAnd );
      assert( TK_BITOR==OP_BitOr );
      assert( TK_SLASH==OP_Divide );
      assert( TK_LSHIFT==OP_ShiftLeft );
      assert( TK_RSHIFT==OP_ShiftRight );
      assert( TK_CONCAT==OP_Concat );
      r1 = sqlite3ExprCode(pParse, pExpr->pLeft, -1);
      r2 = sqlite3ExprCode(pParse, pExpr->pRight, -1);
      sqlite3VdbeAddOp3(v, op, r2, r1, target);
      inReg = target;
      break;
    }
    case TK_UMINUS: {
      Expr *pLeft = pExpr->pLeft;
      assert( pLeft );
      if( pLeft->op==TK_FLOAT || pLeft->op==TK_INTEGER ){
        Token *p = &pLeft->token;
        if( pLeft->op==TK_FLOAT ){
          codeReal(v, (char*)p->z, p->n, 1, target);
        }else{
          codeInteger(v, (char*)p->z, p->n, 1, target);
        }
      }else{
        int r1 = ++pParse->nMem;
        sqlite3VdbeAddOp2(v, OP_Integer, 0, r1);
        sqlite3ExprCode(pParse, pExpr->pLeft, target);
        sqlite3VdbeAddOp3(v, OP_Subtract, target, r1, target);
      }
      inReg = target;
      break;
    }
    case TK_BITNOT:
    case TK_NOT: {
      assert( TK_BITNOT==OP_BitNot );
      assert( TK_NOT==OP_Not );
      sqlite3ExprCode(pParse, pExpr->pLeft, 0);
      sqlite3VdbeAddOp0(v, op);
      break;
    }
    case TK_ISNULL:
    case TK_NOTNULL: {
      int addr;
      assert( TK_ISNULL==OP_IsNull );
      assert( TK_NOTNULL==OP_NotNull );
      sqlite3VdbeAddOp2(v, OP_Integer, 1, target);
      sqlite3ExprCode(pParse, pExpr->pLeft, 0);
      addr = sqlite3VdbeAddOp0(v, op);
      sqlite3VdbeAddOp2(v, OP_AddImm, target, -1);
      sqlite3VdbeJumpHere(v, addr);
      inReg = target;
      break;
    }
    case TK_AGG_FUNCTION: {
      AggInfo *pInfo = pExpr->pAggInfo;
      if( pInfo==0 ){
        sqlite3ErrorMsg(pParse, "misuse of aggregate: %T",
            &pExpr->span);
................................................................................

      zId = (char*)pExpr->token.z;
      nId = pExpr->token.n;
      pDef = sqlite3FindFunction(pParse->db, zId, nId, nExpr, enc, 0);
      assert( pDef!=0 );
      if( pList ){
        nExpr = pList->nExpr;

        sqlite3ExprCodeExprList(pParse, pList, 0);
      }else{
        nExpr = 0;
      }
#ifndef SQLITE_OMIT_VIRTUALTABLE
      /* Possibly overload the function if the first argument is
      ** a virtual table column.
      **
................................................................................
          pColl = sqlite3ExprCollSeq(pParse, pList->a[i].pExpr);
        }
      }
      if( pDef->needCollSeq ){
        if( !pColl ) pColl = pParse->db->pDfltColl; 
        sqlite3VdbeAddOp4(v, OP_CollSeq, 0, 0, 0, (char *)pColl, P4_COLLSEQ);
      }
      sqlite3VdbeAddOp4(v, OP_Function, constMask, 0, 0,
                        (char*)pDef, P4_FUNCDEF);
      sqlite3VdbeChangeP5(v, nExpr);



      break;
    }
#ifndef SQLITE_OMIT_SUBQUERY
    case TK_EXISTS:
    case TK_SELECT: {
      if( pExpr->iColumn==0 ){
        sqlite3CodeSubselect(pParse, pExpr);
................................................................................
      inReg = pExpr->iColumn;
      break;
    }
    case TK_IN: {
      int j1, j2, j3, j4, j5;
      char affinity;
      int eType;
      int r1, r2, r3;

      eType = sqlite3FindInIndex(pParse, pExpr, 0);

      /* Figure out the affinity to use to create a key from the results
      ** of the expression. affinityStr stores a static string suitable for
      ** P4 of OP_MakeRecord.
      */
      affinity = comparisonAffinity(pExpr);

      if( target ){
        r1 = target;
      }else{
        r1 = sqlite3GetTempReg(pParse);
      }
      inReg = r1;
      sqlite3VdbeAddOp2(v, OP_Integer, 1, r1);

      /* Code the <expr> from "<expr> IN (...)". The temporary table
      ** pExpr->iTable contains the values that make up the (...) set.
      */
      r2 = sqlite3ExprCode(pParse, pExpr->pLeft, -1);
      j1 = sqlite3VdbeAddOp1(v, OP_NotNull, r2);
      sqlite3VdbeAddOp2(v, OP_Null, 0, r1);
      j2  = sqlite3VdbeAddOp0(v, OP_Goto);
      sqlite3VdbeJumpHere(v, j1);
      if( eType==IN_INDEX_ROWID ){
        j3 = sqlite3VdbeAddOp3(v, OP_MustBeInt, r2, 0, 1);
        j4 = sqlite3VdbeAddOp3(v, OP_NotExists, pExpr->iTable, 0, r2);
        j5 = sqlite3VdbeAddOp0(v, OP_Goto);
        sqlite3VdbeJumpHere(v, j3);
        sqlite3VdbeJumpHere(v, j4);
      }else{
        r3 = sqlite3GetTempReg(pParse);
        sqlite3VdbeAddOp4(v, OP_RegMakeRec, r2, 1, r3, &affinity, 1);
        j5 = sqlite3VdbeAddOp3(v, OP_Found, pExpr->iTable, 0, r3);
        sqlite3ReleaseTempReg(pParse, r3);
      }
      sqlite3VdbeAddOp2(v, OP_AddImm, r1, -1);
      sqlite3VdbeJumpHere(v, j2);
      sqlite3VdbeJumpHere(v, j5);
      break;
    }
#endif











    case TK_BETWEEN: {
      Expr *pLeft = pExpr->pLeft;
      struct ExprList_item *pLItem = pExpr->pList->a;
      Expr *pRight = pLItem->pExpr;
      int r1, r2, r3, r4, r5;

      if( target>0 ){
        inReg = target;
      }else{
        inReg = ++pParse->nMem;
      }
      r1 = sqlite3ExprCode(pParse, pLeft, -1);
      r2 = sqlite3ExprCode(pParse, pRight, -1);
      r3 = ++pParse->nMem;

      codeCompare(pParse, pLeft, pRight, OP_Ge,
                  r1, r2, r3, SQLITE_STOREP2);
      pLItem++;
      pRight = pLItem->pExpr;

      r4 = sqlite3ExprCode(pParse, pRight, -1);
      r5 = ++pParse->nMem;
      codeCompare(pParse, pLeft, pRight, OP_Le, r1, r4, r5, SQLITE_STOREP2);
      sqlite3VdbeAddOp3(v, OP_And, r3, r5, inReg);

      break;
    }
    case TK_UPLUS: {
      inReg = sqlite3ExprCode(pParse, pExpr->pLeft, origTarget);
      break;
    }






















    case TK_CASE: {
      int expr_end_label;
      int jumpInst;
      int nExpr;
      int i;




      ExprList *pEList;
      struct ExprList_item *aListelem;





      assert(pExpr->pList);
      assert((pExpr->pList->nExpr % 2) == 0);
      assert(pExpr->pList->nExpr > 0);
      pEList = pExpr->pList;
      aListelem = pEList->a;
      nExpr = pEList->nExpr;
      expr_end_label = sqlite3VdbeMakeLabel(v);
      if( pExpr->pLeft ){
        sqlite3ExprCode(pParse, pExpr->pLeft, 0);
      }
      for(i=0; i<nExpr; i=i+2){
        sqlite3ExprCode(pParse, aListelem[i].pExpr, 0);
        if( pExpr->pLeft ){
          sqlite3VdbeAddOp1(v, OP_SCopy, -1);
          jumpInst = codeCompare(pParse, pExpr->pLeft, aListelem[i].pExpr,
                                 OP_Ne, 0, 0, 0, SQLITE_JUMPIFNULL);
          sqlite3VdbeAddOp1(v, OP_Pop, 1);
        }else{
          jumpInst = sqlite3VdbeAddOp3(v, OP_IfNot, 0, 0, 1);
        }
        sqlite3ExprCode(pParse, aListelem[i+1].pExpr, target);
        sqlite3VdbeAddOp2(v, OP_Goto, 0, expr_end_label);
        sqlite3VdbeJumpHere(v, jumpInst);
      }
      if( pExpr->pLeft ){
        sqlite3VdbeAddOp2(v, OP_Pop, 1, 0);
      }
      if( pExpr->pRight ){
        sqlite3ExprCode(pParse, pExpr->pRight, target);
      }else{
        sqlite3VdbeAddOp2(v, OP_Null, 0, target);
      }
      sqlite3VdbeResolveLabel(v, expr_end_label);
      inReg = target;
      break;
    }
#ifndef SQLITE_OMIT_TRIGGER
    case TK_RAISE: {
      if( !pParse->trigStack ){
        sqlite3ErrorMsg(pParse,
                       "RAISE() may only be used within a trigger-program");
................................................................................
         sqlite3VdbeAddOp2(v, OP_Goto, 0, pParse->trigStack->ignoreJump);
         VdbeComment((v, "raise(IGNORE)"));
      }
      break;
    }
#endif
  }


  if( inReg!=target ){
    if( origTarget!=-1 ){
      sqlite3VdbeAddOp2(v, (inReg>0 ? OP_SCopy : OP_Move), inReg, target);
















    }else{
      target = inReg;


    }













  }
  return target;
}

#ifndef SQLITE_OMIT_TRIGGER
/*
** Generate code that evalutes the given expression and leaves the result

** on the stack.  See also sqlite3ExprCode().

**
** This routine might also cache the result and modify the pExpr tree
** so that it will make use of the cached result on subsequent evaluations
** rather than evaluate the whole expression again.  Trivial expressions are
** not cached.  If the expression is cached, its result is stored in a 
** memory location.



*/
void sqlite3ExprCodeAndCache(Parse *pParse, Expr *pExpr, int target){
  Vdbe *v = pParse->pVdbe;
  VdbeOp *pOp;
  int iMem;
  int addr1, addr2;
  if( v==0 ) return;
  addr1 = sqlite3VdbeCurrentAddr(v);
  sqlite3ExprCode(pParse, pExpr, target);

  addr2 = sqlite3VdbeCurrentAddr(v);
  if( addr2>addr1+1
   || ((pOp = sqlite3VdbeGetOp(v, addr1))!=0 && pOp->opcode==OP_Function) ){

    iMem = pExpr->iTable = ++pParse->nMem;
    sqlite3VdbeAddOp2(v, OP_Copy, target, iMem);


    pExpr->op = TK_REGISTER;
  }

}
#endif


/*
** Generate code that pushes the value of every element of the given
** expression list onto the stack if target==0 or into a sequence of
** registers beginning at target.
**
** Return the number of elements evaluated.
................................................................................
** operation.  Special comments in vdbe.c and the mkopcodeh.awk script in
** the make process cause these values to align.  Assert()s in the code
** below verify that the numbers are aligned correctly.
*/
void sqlite3ExprIfTrue(Parse *pParse, Expr *pExpr, int dest, int jumpIfNull){
  Vdbe *v = pParse->pVdbe;
  int op = 0;




  assert( jumpIfNull==SQLITE_JUMPIFNULL || jumpIfNull==0 );
  if( v==0 || pExpr==0 ) return;
  op = pExpr->op;
  switch( op ){
    case TK_AND: {
      int d2 = sqlite3VdbeMakeLabel(v);
      sqlite3ExprIfFalse(pParse, pExpr->pLeft, d2,jumpIfNull^SQLITE_JUMPIFNULL);
................................................................................
    case TK_EQ: {
      assert( TK_LT==OP_Lt );
      assert( TK_LE==OP_Le );
      assert( TK_GT==OP_Gt );
      assert( TK_GE==OP_Ge );
      assert( TK_EQ==OP_Eq );
      assert( TK_NE==OP_Ne );
      sqlite3ExprCode(pParse, pExpr->pLeft, 0);
      sqlite3ExprCode(pParse, pExpr->pRight, 0);
      codeCompare(pParse, pExpr->pLeft, pExpr->pRight, op,
                  0, 0, dest, jumpIfNull);
      break;
    }
    case TK_ISNULL:
    case TK_NOTNULL: {
      assert( TK_ISNULL==OP_IsNull );
      assert( TK_NOTNULL==OP_NotNull );
      sqlite3ExprCode(pParse, pExpr->pLeft, 0);
      sqlite3VdbeAddOp2(v, op, 0, dest);
      break;
    }
    case TK_BETWEEN: {
      /* The expression "x BETWEEN y AND z" is implemented as:
      **
      ** 1 IF (x < y) GOTO 3
      ** 2 IF (x <= z) GOTO <dest>
      ** 3 ...
      */
      int addr;
      Expr *pLeft = pExpr->pLeft;
      Expr *pRight = pExpr->pList->a[0].pExpr;
      sqlite3ExprCode(pParse, pLeft, 0);
      sqlite3VdbeAddOp0(v, OP_Copy);
      sqlite3ExprCode(pParse, pRight, 0);
      addr = codeCompare(pParse, pLeft, pRight, OP_Lt, 0, 0, 0,
                         jumpIfNull ^ SQLITE_JUMPIFNULL);

      pRight = pExpr->pList->a[1].pExpr;
      sqlite3ExprCode(pParse, pRight, 0);
      codeCompare(pParse, pLeft, pRight, OP_Le, 0, 0, dest, jumpIfNull);

      sqlite3VdbeAddOp2(v, OP_Integer, 0, 0);
      sqlite3VdbeJumpHere(v, addr);
      sqlite3VdbeAddOp2(v, OP_Pop, 1, 0);
      break;
    }
    default: {
      sqlite3ExprCode(pParse, pExpr, 0);
      sqlite3VdbeAddOp3(v, OP_If, 0, dest, jumpIfNull!=0);





      break;
    }
  }


}

/*
** Generate code for a boolean expression such that a jump is made
** to the label "dest" if the expression is false but execution
** continues straight thru if the expression is true.
**
................................................................................
** If the expression evaluates to NULL (neither true nor false) then
** jump if jumpIfNull is SQLITE_JUMPIFNULL or fall through if jumpIfNull
** is 0.
*/
void sqlite3ExprIfFalse(Parse *pParse, Expr *pExpr, int dest, int jumpIfNull){
  Vdbe *v = pParse->pVdbe;
  int op = 0;




  assert( jumpIfNull==SQLITE_JUMPIFNULL || jumpIfNull==0 );
  if( v==0 || pExpr==0 ) return;

  /* The value of pExpr->op and op are related as follows:
  **
  **       pExpr->op            op
  **       ---------          ----------
................................................................................
    }
    case TK_LT:
    case TK_LE:
    case TK_GT:
    case TK_GE:
    case TK_NE:
    case TK_EQ: {
      sqlite3ExprCode(pParse, pExpr->pLeft, 0);
      sqlite3ExprCode(pParse, pExpr->pRight, 0);
      codeCompare(pParse, pExpr->pLeft, pExpr->pRight, op,
                  0, 0, dest, jumpIfNull);
      break;
    }
    case TK_ISNULL:
    case TK_NOTNULL: {
      sqlite3ExprCode(pParse, pExpr->pLeft, 0);
      sqlite3VdbeAddOp2(v, op, 0, dest);
      break;
    }
    case TK_BETWEEN: {
      /* The expression is "x BETWEEN y AND z". It is implemented as:
      **
      ** 1 IF (x >= y) GOTO 3
      ** 2 GOTO <dest>
      ** 3 IF (x > z) GOTO <dest>
      */
      int addr;
      Expr *pLeft = pExpr->pLeft;
      Expr *pRight = pExpr->pList->a[0].pExpr;
      sqlite3ExprCode(pParse, pLeft, 0);
      sqlite3VdbeAddOp0(v, OP_Copy);
      sqlite3ExprCode(pParse, pRight, 0);
      addr = sqlite3VdbeCurrentAddr(v);
      codeCompare(pParse, pLeft, pRight, OP_Ge,
                  0, 0, addr+3, jumpIfNull ^ SQLITE_JUMPIFNULL);

      sqlite3VdbeAddOp2(v, OP_Pop, 1, 0);
      sqlite3VdbeAddOp2(v, OP_Goto, 0, dest);
      pRight = pExpr->pList->a[1].pExpr;
      sqlite3ExprCode(pParse, pRight, 0);
      codeCompare(pParse, pLeft, pRight, OP_Gt,
                  0, 0, dest, jumpIfNull);





      break;
    }
    default: {
      sqlite3ExprCode(pParse, pExpr, 0);
      sqlite3VdbeAddOp3(v, OP_IfNot, 0, dest, jumpIfNull!=0);
      break;
    }
  }


}

/*
** Do a deep comparison of two expression trees.  Return TRUE (non-zero)
** if they are identical and return FALSE if they differ in any way.
**
** Sometimes this routine will return FALSE even if the two expressions
................................................................................
  if( pParse->nTempReg ){
    return pParse->aTempReg[--pParse->nTempReg];
  }else{
    return ++pParse->nMem;
  }
}
void sqlite3ReleaseTempReg(Parse *pParse, int iReg){
  if( pParse->nTempReg<sizeof(pParse->aTempReg)/sizeof(pParse->aTempReg[0]) ){

    pParse->aTempReg[pParse->nTempReg++] = iReg;
  }
}

/*
** Allocate or deallocate a block of nReg consecutive registers
*/

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains routines used for analyzing expressions and
** for generating VDBE code that evaluates expressions in SQLite.
**
** $Id: expr.c,v 1.344 2008/01/12 19:03:49 drh Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>

/*
** Return the 'affinity' of the expression pExpr if any.
**
................................................................................
    }
#endif
  }
}

/*
** Generate code into the current Vdbe to evaluate the given
** expression.  Attempt to store the results in register "target".
** Return the register where results are stored.
**
** With this routine, there is no guaranteed that results will
** be stored in target.  The result might be stored in some other
** register if it is convenient to do so.  The calling function
** must check the return code and move the results to the desired
** register.
*/
static int sqlite3ExprCodeTarget(Parse *pParse, Expr *pExpr, int target){
  Vdbe *v = pParse->pVdbe;  /* The VM under construction */
  int op;                   /* The opcode being coded */
  int inReg = target;       /* Results stored in register inReg */
  int regFree1 = 0;         /* If non-zero free this temporary register */
  int regFree2 = 0;         /* If non-zero free this temporary register */
  int r1, r2, r3;           /* Various register numbers */

  assert( v!=0 || pParse->db->mallocFailed );
  assert( target>=0 );
  if( v==0 ) return 0;





  if( pExpr==0 ){
    op = TK_NULL;
  }else{
    op = pExpr->op;
  }
  switch( op ){
................................................................................
      if( !pAggInfo->directMode ){
        assert( pCol->iMem>0 );
        inReg = pCol->iMem;
        break;
      }else if( pAggInfo->useSortingIdx ){
        sqlite3VdbeAddOp3(v, OP_Column, pAggInfo->sortingIdx,
                              pCol->iSorterColumn, target);

        break;
      }
      /* Otherwise, fall thru into the TK_COLUMN case */
    }
    case TK_COLUMN: {
      if( pExpr->iTable<0 ){
        /* This only happens when coding check constraints */
        assert( pParse->ckBase>0 );
        inReg = pExpr->iColumn + pParse->ckBase;
      }else{
        sqlite3ExprCodeGetColumn(v, pExpr->pTab,
                                 pExpr->iColumn, pExpr->iTable, target);

      }
      break;
    }
    case TK_INTEGER: {
      codeInteger(v, (char*)pExpr->token.z, pExpr->token.n, 0, target);

      break;
    }
    case TK_FLOAT: {
      codeReal(v, (char*)pExpr->token.z, pExpr->token.n, 0, target);

      break;
    }
    case TK_STRING: {
      sqlite3DequoteExpr(pParse->db, pExpr);
      sqlite3VdbeAddOp4(v,OP_String8, 0, target, 0,
                        (char*)pExpr->token.z, pExpr->token.n);

      break;
    }
    case TK_NULL: {
      sqlite3VdbeAddOp2(v, OP_Null, 0, target);

      break;
    }
#ifndef SQLITE_OMIT_BLOB_LITERAL
    case TK_BLOB: {
      int n;
      const char *z;
      assert( TK_BLOB==OP_HexBlob );
................................................................................
      n = pExpr->token.n - 3;
      z = (char*)pExpr->token.z + 2;
      assert( n>=0 );
      if( n==0 ){
        z = "";
      }
      sqlite3VdbeAddOp4(v, op, 0, target, 0, z, n);

      break;
    }
#endif
    case TK_VARIABLE: {
      sqlite3VdbeAddOp2(v, OP_Variable, pExpr->iTable, target);
      if( pExpr->token.n>1 ){
        sqlite3VdbeChangeP4(v, -1, (char*)pExpr->token.z, pExpr->token.n);
      }

      break;
    }
    case TK_REGISTER: {
      inReg = pExpr->iTable;
      break;
    }
#ifndef SQLITE_OMIT_CAST
    case TK_CAST: {
      /* Expressions of the form:   CAST(pLeft AS token) */
      int aff, to_op;
      inReg = sqlite3ExprCodeTarget(pParse, pExpr->pLeft, target);
      aff = sqlite3AffinityType(&pExpr->token);
      to_op = aff - SQLITE_AFF_TEXT + OP_ToText;
      assert( to_op==OP_ToText    || aff!=SQLITE_AFF_TEXT    );
      assert( to_op==OP_ToBlob    || aff!=SQLITE_AFF_NONE    );
      assert( to_op==OP_ToNumeric || aff!=SQLITE_AFF_NUMERIC );
      assert( to_op==OP_ToInt     || aff!=SQLITE_AFF_INTEGER );
      assert( to_op==OP_ToReal    || aff!=SQLITE_AFF_REAL    );
      sqlite3VdbeAddOp1(v, to_op, inReg);

      break;
    }
#endif /* SQLITE_OMIT_CAST */
    case TK_LT:
    case TK_LE:
    case TK_GT:
    case TK_GE:
    case TK_NE:
    case TK_EQ: {

      assert( TK_LT==OP_Lt );
      assert( TK_LE==OP_Le );
      assert( TK_GT==OP_Gt );
      assert( TK_GE==OP_Ge );
      assert( TK_EQ==OP_Eq );
      assert( TK_NE==OP_Ne );
      if( target==0 ){


        inReg = ++pParse->nMem;
      }
      r1 = sqlite3ExprCodeTemp(pParse, pExpr->pLeft, &regFree1);
      r2 = sqlite3ExprCodeTemp(pParse, pExpr->pRight, &regFree2);
      codeCompare(pParse, pExpr->pLeft, pExpr->pRight, op,
                  r1, r2, inReg, SQLITE_STOREP2);
      break;
    }
    case TK_AND:
    case TK_OR:
    case TK_PLUS:
................................................................................
    case TK_REM:
    case TK_BITAND:
    case TK_BITOR:
    case TK_SLASH:
    case TK_LSHIFT:
    case TK_RSHIFT: 
    case TK_CONCAT: {

      assert( TK_AND==OP_And );
      assert( TK_OR==OP_Or );
      assert( TK_PLUS==OP_Add );
      assert( TK_MINUS==OP_Subtract );
      assert( TK_REM==OP_Remainder );
      assert( TK_BITAND==OP_BitAnd );
      assert( TK_BITOR==OP_BitOr );
      assert( TK_SLASH==OP_Divide );
      assert( TK_LSHIFT==OP_ShiftLeft );
      assert( TK_RSHIFT==OP_ShiftRight );
      assert( TK_CONCAT==OP_Concat );
      r1 = sqlite3ExprCodeTemp(pParse, pExpr->pLeft, &regFree1);
      r2 = sqlite3ExprCodeTemp(pParse, pExpr->pRight, &regFree2);
      sqlite3VdbeAddOp3(v, op, r2, r1, target);

      break;
    }
    case TK_UMINUS: {
      Expr *pLeft = pExpr->pLeft;
      assert( pLeft );
      if( pLeft->op==TK_FLOAT || pLeft->op==TK_INTEGER ){
        Token *p = &pLeft->token;
        if( pLeft->op==TK_FLOAT ){
          codeReal(v, (char*)p->z, p->n, 1, target);
        }else{
          codeInteger(v, (char*)p->z, p->n, 1, target);
        }
      }else{
        regFree1 = r1 = sqlite3GetTempReg(pParse);
        sqlite3VdbeAddOp2(v, OP_Integer, 0, r1);
        r2 = sqlite3ExprCodeTarget(pParse, pExpr->pLeft, target);
        sqlite3VdbeAddOp3(v, OP_Subtract, r2, r1, target);
      }
      inReg = target;
      break;
    }
    case TK_BITNOT:
    case TK_NOT: {
      assert( TK_BITNOT==OP_BitNot );
      assert( TK_NOT==OP_Not );
      inReg = sqlite3ExprCodeTarget(pParse, pExpr->pLeft, target);
      sqlite3VdbeAddOp1(v, op, inReg);
      break;
    }
    case TK_ISNULL:
    case TK_NOTNULL: {
      int addr;
      assert( TK_ISNULL==OP_IsNull );
      assert( TK_NOTNULL==OP_NotNull );
      sqlite3VdbeAddOp2(v, OP_Integer, 1, target);
      r1 = sqlite3ExprCodeTemp(pParse, pExpr->pLeft, &regFree1);
      addr = sqlite3VdbeAddOp1(v, op, r1);
      sqlite3VdbeAddOp2(v, OP_AddImm, target, -1);
      sqlite3VdbeJumpHere(v, addr);

      break;
    }
    case TK_AGG_FUNCTION: {
      AggInfo *pInfo = pExpr->pAggInfo;
      if( pInfo==0 ){
        sqlite3ErrorMsg(pParse, "misuse of aggregate: %T",
            &pExpr->span);
................................................................................

      zId = (char*)pExpr->token.z;
      nId = pExpr->token.n;
      pDef = sqlite3FindFunction(pParse->db, zId, nId, nExpr, enc, 0);
      assert( pDef!=0 );
      if( pList ){
        nExpr = pList->nExpr;
        r1 = sqlite3GetTempRange(pParse, nExpr);
        sqlite3ExprCodeExprList(pParse, pList, r1);
      }else{
        nExpr = 0;
      }
#ifndef SQLITE_OMIT_VIRTUALTABLE
      /* Possibly overload the function if the first argument is
      ** a virtual table column.
      **
................................................................................
          pColl = sqlite3ExprCollSeq(pParse, pList->a[i].pExpr);
        }
      }
      if( pDef->needCollSeq ){
        if( !pColl ) pColl = pParse->db->pDfltColl; 
        sqlite3VdbeAddOp4(v, OP_CollSeq, 0, 0, 0, (char *)pColl, P4_COLLSEQ);
      }
      sqlite3VdbeAddOp4(v, OP_Function, constMask, r1, target,
                        (char*)pDef, P4_FUNCDEF);
      sqlite3VdbeChangeP5(v, nExpr);
      if( nExpr ){
        sqlite3ReleaseTempRange(pParse, r1, nExpr);
      }
      break;
    }
#ifndef SQLITE_OMIT_SUBQUERY
    case TK_EXISTS:
    case TK_SELECT: {
      if( pExpr->iColumn==0 ){
        sqlite3CodeSubselect(pParse, pExpr);
................................................................................
      inReg = pExpr->iColumn;
      break;
    }
    case TK_IN: {
      int j1, j2, j3, j4, j5;
      char affinity;
      int eType;


      eType = sqlite3FindInIndex(pParse, pExpr, 0);

      /* Figure out the affinity to use to create a key from the results
      ** of the expression. affinityStr stores a static string suitable for
      ** P4 of OP_MakeRecord.
      */
      affinity = comparisonAffinity(pExpr);

      if( target==0 ){
        target = inReg = ++pParse->nMem;


      }

      sqlite3VdbeAddOp2(v, OP_Integer, 1, target);

      /* Code the <expr> from "<expr> IN (...)". The temporary table
      ** pExpr->iTable contains the values that make up the (...) set.
      */
      r1 = sqlite3ExprCodeTemp(pParse, pExpr->pLeft, &regFree1);
      j1 = sqlite3VdbeAddOp1(v, OP_NotNull, r1);
      sqlite3VdbeAddOp2(v, OP_Null, 0, target);
      j2  = sqlite3VdbeAddOp0(v, OP_Goto);
      sqlite3VdbeJumpHere(v, j1);
      if( eType==IN_INDEX_ROWID ){
        j3 = sqlite3VdbeAddOp3(v, OP_MustBeInt, r1, 0, 1);
        j4 = sqlite3VdbeAddOp3(v, OP_NotExists, pExpr->iTable, 0, r1);
        j5 = sqlite3VdbeAddOp0(v, OP_Goto);
        sqlite3VdbeJumpHere(v, j3);
        sqlite3VdbeJumpHere(v, j4);
      }else{
        r2 = regFree2 = sqlite3GetTempReg(pParse);
        sqlite3VdbeAddOp4(v, OP_RegMakeRec, r1, 1, r2, &affinity, 1);
        j5 = sqlite3VdbeAddOp3(v, OP_Found, pExpr->iTable, 0, r2);

      }
      sqlite3VdbeAddOp2(v, OP_AddImm, target, -1);
      sqlite3VdbeJumpHere(v, j2);
      sqlite3VdbeJumpHere(v, j5);
      break;
    }
#endif
    /*
    **    x BETWEEN y AND z
    **
    ** This is equivalent to
    **
    **    x>=y AND x<=z
    **
    ** X is stored in pExpr->pLeft.
    ** Y is stored in pExpr->pList->a[0].pExpr.
    ** Z is stored in pExpr->pList->a[1].pExpr.
    */
    case TK_BETWEEN: {
      Expr *pLeft = pExpr->pLeft;
      struct ExprList_item *pLItem = pExpr->pList->a;
      Expr *pRight = pLItem->pExpr;


      if( target==0 ){
        inReg = target = ++pParse->nMem;


      }
      r1 = sqlite3ExprCodeTemp(pParse, pLeft, &regFree1);
      r2 = sqlite3ExprCodeTemp(pParse, pRight, &regFree2);

      r3 = sqlite3GetTempReg(pParse);
      codeCompare(pParse, pLeft, pRight, OP_Ge,
                  r1, r2, r3, SQLITE_STOREP2);
      pLItem++;
      pRight = pLItem->pExpr;
      sqlite3ReleaseTempReg(pParse, regFree2);
      r2 = sqlite3ExprCodeTemp(pParse, pRight, &regFree2);

      codeCompare(pParse, pLeft, pRight, OP_Le, r1, r2, r2, SQLITE_STOREP2);
      sqlite3VdbeAddOp3(v, OP_And, r3, r2, target);
      sqlite3ReleaseTempReg(pParse, r3);
      break;
    }
    case TK_UPLUS: {
      inReg = sqlite3ExprCodeTarget(pParse, pExpr->pLeft, target);
      break;
    }

    /*
    ** Form A:
    **   CASE x WHEN e1 THEN r1 WHEN e2 THEN r2 ... WHEN eN THEN rN ELSE y END
    **
    ** Form B:
    **   CASE WHEN e1 THEN r1 WHEN e2 THEN r2 ... WHEN eN THEN rN ELSE y END
    **
    ** Form A is can be transformed into the equivalent form B as follows:
    **   CASE WHEN x=e1 THEN r1 WHEN x=e2 THEN r2 ...
    **        WHEN x=eN THEN rN ELSE y END
    **
    ** X (if it exists) is in pExpr->pLeft.
    ** Y is in pExpr->pRight.  The Y is also optional.  If there is no
    ** ELSE clause and no other term matches, then the result of the
    ** exprssion is NULL.
    ** Ei is in pExpr->pList->a[i*2] and Ri is pExpr->pList->a[i*2+1].
    **
    ** The result of the expression is the Ri for the first matching Ei,
    ** or if there is no matching Ei, the ELSE term Y, or if there is
    ** no ELSE term, NULL.
    */
    case TK_CASE: {




      int endLabel;                     /* GOTO label for end of CASE stmt */
      int nextCase;                     /* GOTO label for next WHEN clause */
      int nExpr;                        /* 2x number of WHEN terms */
      int i;                            /* Loop counter */
      ExprList *pEList;                 /* List of WHEN terms */
      struct ExprList_item *aListelem;  /* Array of WHEN terms */
      Expr opCompare;                   /* The X==Ei expression */
      Expr cacheX;                      /* Cached expression X */
      Expr *pX;                         /* The X expression */
      Expr *pTest;                      /* X==Ei (form A) or just Ei (form B) */

      assert(pExpr->pList);
      assert((pExpr->pList->nExpr % 2) == 0);
      assert(pExpr->pList->nExpr > 0);
      pEList = pExpr->pList;
      aListelem = pEList->a;
      nExpr = pEList->nExpr;
      endLabel = sqlite3VdbeMakeLabel(v);
      if( (pX = pExpr->pLeft)!=0 ){
        cacheX = *pX;
        cacheX.iTable = sqlite3ExprCodeTemp(pParse, pX, &regFree1);
        cacheX.op = TK_REGISTER;
        opCompare.op = TK_EQ;
        opCompare.pLeft = &cacheX;
        pTest = &opCompare;
      }
      for(i=0; i<nExpr; i=i+2){
        if( pX ){
          opCompare.pRight = aListelem[i].pExpr;
        }else{
          pTest = aListelem[i].pExpr;
        }
        nextCase = sqlite3VdbeMakeLabel(v);
        sqlite3ExprIfFalse(pParse, pTest, nextCase, SQLITE_JUMPIFNULL);
        sqlite3ExprCode(pParse, aListelem[i+1].pExpr, target);
        sqlite3VdbeAddOp2(v, OP_Goto, 0, endLabel);
        sqlite3VdbeResolveLabel(v, nextCase);
      }
      if( pExpr->pRight ){
        sqlite3ExprCode(pParse, pExpr->pRight, target);
      }else{
        sqlite3VdbeAddOp2(v, OP_Null, 0, target);
      }
      sqlite3VdbeResolveLabel(v, endLabel);

      break;
    }
#ifndef SQLITE_OMIT_TRIGGER
    case TK_RAISE: {
      if( !pParse->trigStack ){
        sqlite3ErrorMsg(pParse,
                       "RAISE() may only be used within a trigger-program");
................................................................................
         sqlite3VdbeAddOp2(v, OP_Goto, 0, pParse->trigStack->ignoreJump);
         VdbeComment((v, "raise(IGNORE)"));
      }
      break;
    }
#endif
  }
  sqlite3ReleaseTempReg(pParse, regFree1);
  sqlite3ReleaseTempReg(pParse, regFree2);
  return inReg;


}

/*
** Generate code to evaluate an expression and store the results
** into a register.  Return the register number where the results
** are stored.
**
** If the register is a temporary register that can be deallocated,
** then write its number into *pReg.  If the result register is no
** a temporary, then set *pReg to zero.
*/
int sqlite3ExprCodeTemp(Parse *pParse, Expr *pExpr, int *pReg){
  int r1 = sqlite3GetTempReg(pParse);
  int r2 = sqlite3ExprCodeTarget(pParse, pExpr, r1);
  if( r2==r1 ){
    *pReg = r1;
  }else{

    sqlite3ReleaseTempReg(pParse, r1);
    *pReg = 0;
  }
  return r2;
}

/*
** Generate code that will evaluate expression pExpr and store the
** results in register target.  The results are guaranteed to appear
** in register target.
*/
int sqlite3ExprCode(Parse *pParse, Expr *pExpr, int target){
  int inReg = sqlite3ExprCodeTarget(pParse, pExpr, target);
  if( inReg!=target ){
    sqlite3VdbeAddOp2(pParse->pVdbe, (inReg>0 ? OP_SCopy : OP_Move), 
                      inReg, target);
  }
  return target;
}


/*
** Generate code that evalutes the given expression and puts the result
** in register target.  If target==-1, then allocate a temporary register
** in which to store the result.  In either case, return the register
** number where the result is stored.
**

** Also make a copy of the expression results into another "cache" register
** and modify the expression so that the next time it is evaluated,
** the result is a copy of the cache register.
**
** This routine is used for expressions that are used multiple 
** times.  They are evaluated once and the results of the expression
** are reused.
*/
int sqlite3ExprCodeAndCache(Parse *pParse, Expr *pExpr, int target){
  Vdbe *v = pParse->pVdbe;

  int inReg;



  inReg = sqlite3ExprCode(pParse, pExpr, target);
  if( pExpr->op!=TK_REGISTER ){  
    int iMem;
    if( target<0 ){
      iMem = inReg;
    }else{
      iMem = ++pParse->nMem;
      sqlite3VdbeAddOp2(v, OP_Copy, inReg, iMem);
    }
    pExpr->iTable = iMem;
    pExpr->op = TK_REGISTER;
  }
  return inReg;
}



/*
** Generate code that pushes the value of every element of the given
** expression list onto the stack if target==0 or into a sequence of
** registers beginning at target.
**
** Return the number of elements evaluated.
................................................................................
** operation.  Special comments in vdbe.c and the mkopcodeh.awk script in
** the make process cause these values to align.  Assert()s in the code
** below verify that the numbers are aligned correctly.
*/
void sqlite3ExprIfTrue(Parse *pParse, Expr *pExpr, int dest, int jumpIfNull){
  Vdbe *v = pParse->pVdbe;
  int op = 0;
  int regFree1 = 0;
  int regFree2 = 0;
  int r1, r2;

  assert( jumpIfNull==SQLITE_JUMPIFNULL || jumpIfNull==0 );
  if( v==0 || pExpr==0 ) return;
  op = pExpr->op;
  switch( op ){
    case TK_AND: {
      int d2 = sqlite3VdbeMakeLabel(v);
      sqlite3ExprIfFalse(pParse, pExpr->pLeft, d2,jumpIfNull^SQLITE_JUMPIFNULL);
................................................................................
    case TK_EQ: {
      assert( TK_LT==OP_Lt );
      assert( TK_LE==OP_Le );
      assert( TK_GT==OP_Gt );
      assert( TK_GE==OP_Ge );
      assert( TK_EQ==OP_Eq );
      assert( TK_NE==OP_Ne );
      r1 = sqlite3ExprCodeTemp(pParse, pExpr->pLeft, &regFree1);
      r2 = sqlite3ExprCodeTemp(pParse, pExpr->pRight, &regFree2);
      codeCompare(pParse, pExpr->pLeft, pExpr->pRight, op,
                  r1, r2, dest, jumpIfNull);
      break;
    }
    case TK_ISNULL:
    case TK_NOTNULL: {
      assert( TK_ISNULL==OP_IsNull );
      assert( TK_NOTNULL==OP_NotNull );
      r1 = sqlite3ExprCodeTemp(pParse, pExpr->pLeft, &regFree1);
      sqlite3VdbeAddOp2(v, op, r1, dest);
      break;
    }
    case TK_BETWEEN: {
      /*    x BETWEEN y AND z
      **
      ** Is equivalent to 
      **
      **    x>=y AND x<=z
      **
      ** Code it as such, taking care to do the common subexpression
      ** elementation of x.
      */
      Expr exprAnd;
      Expr compLeft;
      Expr compRight;
      Expr exprX;

      exprX = *pExpr->pLeft;
      exprAnd.op = TK_AND;
      exprAnd.pLeft = &compLeft;
      exprAnd.pRight = &compRight;
      compLeft.op = TK_GE;
      compLeft.pLeft = &exprX;
      compLeft.pRight = pExpr->pList->a[0].pExpr;
      compRight.op = TK_LE;
      compRight.pLeft = &exprX;
      compRight.pRight = pExpr->pList->a[1].pExpr;
      exprX.iTable = sqlite3ExprCodeTemp(pParse, &exprX, &regFree1);
      exprX.op = TK_REGISTER;
      sqlite3ExprIfTrue(pParse, &exprAnd, dest, jumpIfNull);
      break;
    }
    default: {
      r1 = sqlite3ExprCodeTemp(pParse, pExpr, &regFree1);
      sqlite3VdbeAddOp3(v, OP_If, r1, dest, jumpIfNull!=0);
      break;
    }
  }
  sqlite3ReleaseTempReg(pParse, regFree1);
  sqlite3ReleaseTempReg(pParse, regFree2);  
}

/*
** Generate code for a boolean expression such that a jump is made
** to the label "dest" if the expression is false but execution
** continues straight thru if the expression is true.
**
................................................................................
** If the expression evaluates to NULL (neither true nor false) then
** jump if jumpIfNull is SQLITE_JUMPIFNULL or fall through if jumpIfNull
** is 0.
*/
void sqlite3ExprIfFalse(Parse *pParse, Expr *pExpr, int dest, int jumpIfNull){
  Vdbe *v = pParse->pVdbe;
  int op = 0;
  int regFree1 = 0;
  int regFree2 = 0;
  int r1, r2;

  assert( jumpIfNull==SQLITE_JUMPIFNULL || jumpIfNull==0 );
  if( v==0 || pExpr==0 ) return;

  /* The value of pExpr->op and op are related as follows:
  **
  **       pExpr->op            op
  **       ---------          ----------
................................................................................
    }
    case TK_LT:
    case TK_LE:
    case TK_GT:
    case TK_GE:
    case TK_NE:
    case TK_EQ: {
      r1 = sqlite3ExprCodeTemp(pParse, pExpr->pLeft, &regFree1);
      r2 = sqlite3ExprCodeTemp(pParse, pExpr->pRight, &regFree2);
      codeCompare(pParse, pExpr->pLeft, pExpr->pRight, op,
                  r1, r2, dest, jumpIfNull);
      break;
    }
    case TK_ISNULL:
    case TK_NOTNULL: {
      r1 = sqlite3ExprCodeTemp(pParse, pExpr->pLeft, &regFree1);
      sqlite3VdbeAddOp2(v, op, r1, dest);
      break;
    }
    case TK_BETWEEN: {
      /*    x BETWEEN y AND z
      **
      ** Is equivalent to 
      **
      **    x>=y AND x<=z
      **
      ** Code it as such, taking care to do the common subexpression
      ** elementation of x.
      */
      Expr exprAnd;
      Expr compLeft;
      Expr compRight;
      Expr exprX;

      exprX = *pExpr->pLeft;
      exprAnd.op = TK_AND;
      exprAnd.pLeft = &compLeft;
      exprAnd.pRight = &compRight;
      compLeft.op = TK_GE;
      compLeft.pLeft = &exprX;
      compLeft.pRight = pExpr->pList->a[0].pExpr;
      compRight.op = TK_LE;
      compRight.pLeft = &exprX;
      compRight.pRight = pExpr->pList->a[1].pExpr;
      exprX.iTable = sqlite3ExprCodeTemp(pParse, &exprX, &regFree1);
      exprX.op = TK_REGISTER;
      sqlite3ExprIfFalse(pParse, &exprAnd, dest, jumpIfNull);
      break;
    }
    default: {
      r1 = sqlite3ExprCodeTemp(pParse, pExpr, &regFree1);
      sqlite3VdbeAddOp3(v, OP_IfNot, r1, dest, jumpIfNull!=0);
      break;
    }
  }
  sqlite3ReleaseTempReg(pParse, regFree1);
  sqlite3ReleaseTempReg(pParse, regFree2);
}

/*
** Do a deep comparison of two expression trees.  Return TRUE (non-zero)
** if they are identical and return FALSE if they differ in any way.
**
** Sometimes this routine will return FALSE even if the two expressions
................................................................................
  if( pParse->nTempReg ){
    return pParse->aTempReg[--pParse->nTempReg];
  }else{
    return ++pParse->nMem;
  }
}
void sqlite3ReleaseTempReg(Parse *pParse, int iReg){
  if( iReg && pParse->nTempReg<ArraySize(pParse->aTempReg) ){
    assert( iReg>0 );
    pParse->aTempReg[pParse->nTempReg++] = iReg;
  }
}

/*
** Allocate or deallocate a block of nReg consecutive registers
*/

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains C code routines that are called by the parser
** to handle SELECT statements in SQLite.
**
** $Id: select.c,v 1.398 2008/01/12 12:48:08 drh Exp $
*/
#include "sqliteInt.h"


/*
** Delete all the content of a Select structure but do not deallocate
** the select structure itself.
................................................................................
** seen combinations of the N values.  A new entry is made in iTab
** if the current N values are new.
**
** A jump to addrRepeat is made and the N+1 values are popped from the
** stack if the top N elements are not distinct.
*/
static void codeDistinct(
  Vdbe *v,           /* Generate code into this VM */
  int iTab,          /* A sorting index used to test for distinctness */
  int addrRepeat,    /* Jump to here if not distinct */
  int N,             /* Number of elements */
  int iMem           /* First element */
){
  sqlite3VdbeAddOp2(v, OP_RegMakeRec, iMem, N);
  sqlite3VdbeAddOp2(v, OP_Distinct, iTab, sqlite3VdbeCurrentAddr(v)+3);
  sqlite3VdbeAddOp2(v, OP_Pop, 1, 0);
  sqlite3VdbeAddOp2(v, OP_Goto, 0, addrRepeat);
  VdbeComment((v, "skip indistinct records"));
  sqlite3VdbeAddOp2(v, OP_IdxInsert, iTab, 0);



}

/*
** Generate an error message when a SELECT is used within a subexpression
** (example:  "a IN (SELECT * FROM table)") but it has more than 1 result
** column.  We do this in a subroutine because the error occurs in multiple
** places.
................................................................................
  /* If the DISTINCT keyword was present on the SELECT statement
  ** and this row has been seen before, then do not make this row
  ** part of the result.
  */
  if( hasDistinct ){
    assert( pEList!=0 );
    assert( pEList->nExpr==nColumn );
    codeDistinct(v, distinct, iContinue, nColumn, iMem);
    if( pOrderBy==0 ){
      codeOffset(v, p, iContinue);
    }
  }

  if( checkForMultiColumnSelectError(pParse, pDest, pEList->nExpr) ){
    return 0;
................................................................................
    }else{
      nArg = 0;
      regAgg = 0;
    }
    if( pF->iDistinct>=0 ){
      addrNext = sqlite3VdbeMakeLabel(v);
      assert( nArg==1 );
      codeDistinct(v, pF->iDistinct, addrNext, 1, regAgg);
    }
    if( pF->pFunc->needCollSeq ){
      CollSeq *pColl = 0;
      struct ExprList_item *pItem;
      int j;
      assert( pList!=0 );  /* pList!=0 if pF->pFunc->needCollSeq is true */
      for(j=0, pItem=pList->a; !pColl && j<nArg; j++, pItem++){
................................................................................
      ** (b0 is memory location iBMem+0, b1 is iBMem+1, and so forth)
      ** Then compare the current GROUP BY terms against the GROUP BY terms
      ** from the previous row currently stored in a0, a1, a2...
      */
      addrTopOfLoop = sqlite3VdbeCurrentAddr(v);
      for(j=0; j<pGroupBy->nExpr; j++){
        if( groupBySort ){
          sqlite3VdbeAddOp2(v, OP_Column, sAggInfo.sortingIdx, j);
        }else{
          sAggInfo.directMode = 1;
          sqlite3ExprCode(pParse, pGroupBy->a[j].pExpr, 0);
        }
        sqlite3VdbeAddOp2(v, j<pGroupBy->nExpr-1?OP_Move:OP_Copy, 0, iBMem+j);
      }
      for(j=pGroupBy->nExpr-1; j>=0; j--){
        if( j<pGroupBy->nExpr-1 ){
          sqlite3VdbeAddOp2(v, OP_SCopy, iBMem+j, 0);
        }
        sqlite3VdbeAddOp2(v, OP_SCopy, iAMem+j, 0);
        if( j==0 ){
          sqlite3VdbeAddOp2(v, OP_Eq, 0, addrProcessRow);

        }else{
          sqlite3VdbeAddOp2(v, OP_Ne, 0, addrGroupByChange);

        }
        sqlite3VdbeChangeP4(v, -1, (void*)pKeyInfo->aColl[j], P4_COLLSEQ);
        sqlite3VdbeChangeP5(v, SQLITE_NULLEQUAL);
      }

      /* Generate code that runs whenever the GROUP BY changes.
      ** Change in the GROUP BY are detected by the previous code

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains C code routines that are called by the parser
** to handle SELECT statements in SQLite.
**
** $Id: select.c,v 1.399 2008/01/12 19:03:49 drh Exp $
*/
#include "sqliteInt.h"


/*
** Delete all the content of a Select structure but do not deallocate
** the select structure itself.
................................................................................
** seen combinations of the N values.  A new entry is made in iTab
** if the current N values are new.
**
** A jump to addrRepeat is made and the N+1 values are popped from the
** stack if the top N elements are not distinct.
*/
static void codeDistinct(
  Parse *pParse,     /* Parsing and code generating context */
  int iTab,          /* A sorting index used to test for distinctness */
  int addrRepeat,    /* Jump to here if not distinct */
  int N,             /* Number of elements */
  int iMem           /* First element */
){
  Vdbe *v;
  int r1;

  v = pParse->pVdbe;
  r1 = sqlite3GetTempReg(pParse);
  sqlite3VdbeAddOp3(v, OP_RegMakeRec, iMem, N, r1);
  sqlite3VdbeAddOp3(v, OP_Found, iTab, addrRepeat, r1);
  sqlite3VdbeAddOp2(v, OP_IdxInsert, iTab, r1);
  sqlite3ReleaseTempReg(pParse, r1);
}

/*
** Generate an error message when a SELECT is used within a subexpression
** (example:  "a IN (SELECT * FROM table)") but it has more than 1 result
** column.  We do this in a subroutine because the error occurs in multiple
** places.
................................................................................
  /* If the DISTINCT keyword was present on the SELECT statement
  ** and this row has been seen before, then do not make this row
  ** part of the result.
  */
  if( hasDistinct ){
    assert( pEList!=0 );
    assert( pEList->nExpr==nColumn );
    codeDistinct(pParse, distinct, iContinue, nColumn, iMem);
    if( pOrderBy==0 ){
      codeOffset(v, p, iContinue);
    }
  }

  if( checkForMultiColumnSelectError(pParse, pDest, pEList->nExpr) ){
    return 0;
................................................................................
    }else{
      nArg = 0;
      regAgg = 0;
    }
    if( pF->iDistinct>=0 ){
      addrNext = sqlite3VdbeMakeLabel(v);
      assert( nArg==1 );
      codeDistinct(pParse, pF->iDistinct, addrNext, 1, regAgg);
    }
    if( pF->pFunc->needCollSeq ){
      CollSeq *pColl = 0;
      struct ExprList_item *pItem;
      int j;
      assert( pList!=0 );  /* pList!=0 if pF->pFunc->needCollSeq is true */
      for(j=0, pItem=pList->a; !pColl && j<nArg; j++, pItem++){
................................................................................
      ** (b0 is memory location iBMem+0, b1 is iBMem+1, and so forth)
      ** Then compare the current GROUP BY terms against the GROUP BY terms
      ** from the previous row currently stored in a0, a1, a2...
      */
      addrTopOfLoop = sqlite3VdbeCurrentAddr(v);
      for(j=0; j<pGroupBy->nExpr; j++){
        if( groupBySort ){
          sqlite3VdbeAddOp3(v, OP_Column, sAggInfo.sortingIdx, j, iBMem+j);
        }else{
          sAggInfo.directMode = 1;
          sqlite3ExprCode(pParse, pGroupBy->a[j].pExpr, iBMem+j);
        }

      }
      for(j=pGroupBy->nExpr-1; j>=0; j--){




        if( j==0 ){

          sqlite3VdbeAddOp3(v, OP_Eq, iAMem+j, addrProcessRow, iBMem+j);
        }else{

          sqlite3VdbeAddOp3(v, OP_Ne, iAMem+j, addrGroupByChange, iBMem+j);
        }
        sqlite3VdbeChangeP4(v, -1, (void*)pKeyInfo->aColl[j], P4_COLLSEQ);
        sqlite3VdbeChangeP5(v, SQLITE_NULLEQUAL);
      }

      /* Generate code that runs whenever the GROUP BY changes.
      ** Change in the GROUP BY are detected by the previous code

**    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.
**
*************************************************************************
** Internal interface definitions for SQLite.
**
** @(#) $Id: sqliteInt.h,v 1.648 2008/01/12 12:48:08 drh Exp $
*/
#ifndef _SQLITEINT_H_
#define _SQLITEINT_H_

/*
** The macro unlikely() is a hint that surrounds a boolean
** expression that is usually false.  Macro likely() surrounds
................................................................................
  Vdbe *pVdbe;         /* An engine for executing database bytecode */
  u8 colNamesSet;      /* TRUE after OP_ColumnName has been issued to pVdbe */
  u8 nameClash;        /* A permanent table name clashes with temp table name */
  u8 checkSchema;      /* Causes schema cookie check after an error */
  u8 nested;           /* Number of nested calls to the parser/code generator */
  u8 parseError;       /* True after a parsing error.  Ticket #1794 */
  u8 nTempReg;         /* Number of temporary registers in aTempReg[] */

  int aTempReg[8];     /* Holding area for temporary registers */
  int nRangeReg;       /* Size of the temporary register block */
  int iRangeReg;       /* First register in temporary register block */
  int nErr;            /* Number of errors seen */
  int nTab;            /* Number of previously allocated VDBE cursors */
  int nMem;            /* Number of memory cells used so far */
  int nSet;            /* Number of sets used so far */
................................................................................
void sqlite3OpenTable(Parse*, int iCur, int iDb, Table*, int);
void sqlite3DeleteFrom(Parse*, SrcList*, Expr*);
void sqlite3Update(Parse*, SrcList*, ExprList*, Expr*, int);
WhereInfo *sqlite3WhereBegin(Parse*, SrcList*, Expr*, ExprList**, u8);
void sqlite3WhereEnd(WhereInfo*);
void sqlite3ExprCodeGetColumn(Vdbe*, Table*, int, int, int);
int sqlite3ExprCode(Parse*, Expr*, int);

void sqlite3ExprCodeAndCache(Parse*, Expr*, int);
int sqlite3ExprCodeExprList(Parse*, ExprList*, int);
void sqlite3ExprIfTrue(Parse*, Expr*, int, int);
void sqlite3ExprIfFalse(Parse*, Expr*, int, int);
Table *sqlite3FindTable(sqlite3*,const char*, const char*);
Table *sqlite3LocateTable(Parse*,const char*, const char*);
Index *sqlite3FindIndex(sqlite3*,const char*, const char*);
void sqlite3UnlinkAndDeleteTable(sqlite3*,int,const char*);

**    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.
**
*************************************************************************
** Internal interface definitions for SQLite.
**
** @(#) $Id: sqliteInt.h,v 1.649 2008/01/12 19:03:49 drh Exp $
*/
#ifndef _SQLITEINT_H_
#define _SQLITEINT_H_

/*
** The macro unlikely() is a hint that surrounds a boolean
** expression that is usually false.  Macro likely() surrounds
................................................................................
  Vdbe *pVdbe;         /* An engine for executing database bytecode */
  u8 colNamesSet;      /* TRUE after OP_ColumnName has been issued to pVdbe */
  u8 nameClash;        /* A permanent table name clashes with temp table name */
  u8 checkSchema;      /* Causes schema cookie check after an error */
  u8 nested;           /* Number of nested calls to the parser/code generator */
  u8 parseError;       /* True after a parsing error.  Ticket #1794 */
  u8 nTempReg;         /* Number of temporary registers in aTempReg[] */
  u8 nTempInUse;       /* Number of aTempReg[] currently checked out */
  int aTempReg[8];     /* Holding area for temporary registers */
  int nRangeReg;       /* Size of the temporary register block */
  int iRangeReg;       /* First register in temporary register block */
  int nErr;            /* Number of errors seen */
  int nTab;            /* Number of previously allocated VDBE cursors */
  int nMem;            /* Number of memory cells used so far */
  int nSet;            /* Number of sets used so far */
................................................................................
void sqlite3OpenTable(Parse*, int iCur, int iDb, Table*, int);
void sqlite3DeleteFrom(Parse*, SrcList*, Expr*);
void sqlite3Update(Parse*, SrcList*, ExprList*, Expr*, int);
WhereInfo *sqlite3WhereBegin(Parse*, SrcList*, Expr*, ExprList**, u8);
void sqlite3WhereEnd(WhereInfo*);
void sqlite3ExprCodeGetColumn(Vdbe*, Table*, int, int, int);
int sqlite3ExprCode(Parse*, Expr*, int);
int sqlite3ExprCodeTemp(Parse*, Expr*, int*);
int sqlite3ExprCodeAndCache(Parse*, Expr*, int);
int sqlite3ExprCodeExprList(Parse*, ExprList*, int);
void sqlite3ExprIfTrue(Parse*, Expr*, int, int);
void sqlite3ExprIfFalse(Parse*, Expr*, int, int);
Table *sqlite3FindTable(sqlite3*,const char*, const char*);
Table *sqlite3LocateTable(Parse*,const char*, const char*);
Index *sqlite3FindIndex(sqlite3*,const char*, const char*);
void sqlite3UnlinkAndDeleteTable(sqlite3*,int,const char*);

**
** 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 1.693 2008/01/12 12:48:08 drh Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>
#include "vdbeInt.h"

/*
** The following global variable is incremented every time a cursor
................................................................................
    goto too_big;
  }
  sqlite3VdbeMemShallowCopy(pOut, &p->aVar[j], MEM_Static);
  UPDATE_MAX_BLOBSIZE(pOut);
  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: Move P1 P2 * * *
**
** Move the value in P1 into P2.  If P1 is positive then read from the
** P1-th register.  If P1 is zero or negative read from the stack.
** When P1 is 0 read from the top the stack.  When P1 is -1 read from
** the next entry down on the stack.  And so forth.
**
................................................................................
    pArg = &pTos[1-n];
  }else{
    pArg = &p->aMem[pOp->p2];
  }
  for(i=0; i<n; i++, pArg++){
    apVal[i] = pArg;
    storeTypeInfo(pArg, encoding);

  }

  assert( pOp->p4type==P4_FUNCDEF || pOp->p4type==P4_VDBEFUNC );
  if( pOp->p4type==P4_FUNCDEF ){
    ctx.pFunc = pOp->p4.pFunc;
    ctx.pVdbeFunc = 0;
  }else{
................................................................................
  }else{
    pOut = &p->aMem[pOp->p3];
  }
  sqlite3VdbeMemMove(pOut, &ctx.s);
  if( sqlite3VdbeMemTooBig(pOut) ){
    goto too_big;
  }

  UPDATE_MAX_BLOBSIZE(pOut);
  break;
}

/* Opcode: BitAnd P1 P2 P3 * *
**
** Take the bit-wise AND of the values in register P1 and P2 and
................................................................................
        pC->nullRow = 1;
      }
    }
  }
  break;
}

/* Opcode: Distinct P1 P2 P3 * *
**
** Use register P3 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 when P3==0.
**
** 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 P3 * *
**
** Register P3 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 P3 * *
**
** Register P3 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, jump, in3 */
case OP_NotFound:       /* no-push, jump, in3 */
case OP_Found: {        /* no-push, jump, in3 */
  int i = pOp->p1;
  int alreadyExists = 0;
  Cursor *pC;
  assert( i>=0 && i<p->nCursor );
  assert( p->apCsr[i]!=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 ){
    nPop = 0;
  }
  break;
}

/* Opcode: IsUnique P1 P2 P3 P4 *
**
** The P3 register contains an integer record number.  Call this
** record number R.  The P4 register contains an index key created

**
** 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 1.694 2008/01/12 19:03:49 drh Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>
#include "vdbeInt.h"

/*
** The following global variable is incremented every time a cursor
................................................................................
    goto too_big;
  }
  sqlite3VdbeMemShallowCopy(pOut, &p->aVar[j], MEM_Static);
  UPDATE_MAX_BLOBSIZE(pOut);
  break;
}












/* Opcode: Move P1 P2 * * *
**
** Move the value in P1 into P2.  If P1 is positive then read from the
** P1-th register.  If P1 is zero or negative read from the stack.
** When P1 is 0 read from the top the stack.  When P1 is -1 read from
** the next entry down on the stack.  And so forth.
**
................................................................................
    pArg = &pTos[1-n];
  }else{
    pArg = &p->aMem[pOp->p2];
  }
  for(i=0; i<n; i++, pArg++){
    apVal[i] = pArg;
    storeTypeInfo(pArg, encoding);
    REGISTER_TRACE(pOp->p2, pArg);
  }

  assert( pOp->p4type==P4_FUNCDEF || pOp->p4type==P4_VDBEFUNC );
  if( pOp->p4type==P4_FUNCDEF ){
    ctx.pFunc = pOp->p4.pFunc;
    ctx.pVdbeFunc = 0;
  }else{
................................................................................
  }else{
    pOut = &p->aMem[pOp->p3];
  }
  sqlite3VdbeMemMove(pOut, &ctx.s);
  if( sqlite3VdbeMemTooBig(pOut) ){
    goto too_big;
  }
  REGISTER_TRACE(pOp->p3, pOut);
  UPDATE_MAX_BLOBSIZE(pOut);
  break;
}

/* Opcode: BitAnd P1 P2 P3 * *
**
** Take the bit-wise AND of the values in register P1 and P2 and
................................................................................
        pC->nullRow = 1;
      }
    }
  }
  break;
}




















/* Opcode: Found P1 P2 P3 * *
**
** Register P3 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.
**
** 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 is also used to implement the
** DISTINCT keyword in SELECT statements.
**
** 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: NotFound, MoveTo, IsUnique, NotExists
*/
/* Opcode: NotFound P1 P2 P3 * *
**
** Register P3 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_NotFound:       /* no-push, jump, in3 */
case OP_Found: {        /* no-push, jump, in3 */
  int i = pOp->p1;
  int alreadyExists = 0;
  Cursor *pC;
  assert( i>=0 && i<p->nCursor );
  assert( p->apCsr[i]!=0 );
................................................................................
    pC->cacheStatus = CACHE_STALE;
  }
  if( pOp->opcode==OP_Found ){
    if( alreadyExists ) pc = pOp->p2 - 1;
  }else{
    if( !alreadyExists ) pc = pOp->p2 - 1;
  }



  break;
}

/* Opcode: IsUnique P1 P2 P3 P4 *
**
** The P3 register contains an integer record number.  Call this
** record number R.  The P4 register contains an index key created

** This module contains C code that generates VDBE code used to process
** the WHERE clause of SQL statements.  This module is reponsible for
** generating the code that loops through a table looking for applicable
** rows.  Indices are selected and used to speed the search when doing
** so is applicable.  Because this module is responsible for selecting
** indices, you might also think of this module as the "query optimizer".
**
** $Id: where.c,v 1.280 2008/01/09 23:04:13 drh Exp $
*/
#include "sqliteInt.h"

/*
** The number of bits in a Bitmask.  "BMS" means "BitMask Size".
*/
#define BMS  (sizeof(Bitmask)*8)
................................................................................
      ){
        int h;
        isMinQuery = 1;
        for(h=0; h<nEq; h++){
          sqlite3VdbeAddOp1(v, OP_Copy, 1-nEq);
        }
        buildIndexProbe(v, nEq, pIdx);
        sqlite3VdbeAddOp2(v, OP_Copy, 0, pLevel->iMem);
        sqlite3VdbeAddOp2(v, OP_Pop, 1, 0);
        sqlite3VdbeAddOp2(v, OP_Null, 0, 0);
        buildIndexProbe(v, nEq+1, pIdx);
      }else{
        /* Generate a single key that will be used to both start and 
        ** terminate the search
        */
        buildIndexProbe(v, nEq, pIdx);

** This module contains C code that generates VDBE code used to process
** the WHERE clause of SQL statements.  This module is reponsible for
** generating the code that loops through a table looking for applicable
** rows.  Indices are selected and used to speed the search when doing
** so is applicable.  Because this module is responsible for selecting
** indices, you might also think of this module as the "query optimizer".
**
** $Id: where.c,v 1.281 2008/01/12 19:03:49 drh Exp $
*/
#include "sqliteInt.h"

/*
** The number of bits in a Bitmask.  "BMS" means "BitMask Size".
*/
#define BMS  (sizeof(Bitmask)*8)
................................................................................
      ){
        int h;
        isMinQuery = 1;
        for(h=0; h<nEq; h++){
          sqlite3VdbeAddOp1(v, OP_Copy, 1-nEq);
        }
        buildIndexProbe(v, nEq, pIdx);

        sqlite3VdbeAddOp2(v, OP_Move, 0, pLevel->iMem);
        sqlite3VdbeAddOp2(v, OP_Null, 0, 0);
        buildIndexProbe(v, nEq+1, pIdx);
      }else{
        /* Generate a single key that will be used to both start and 
        ** terminate the search
        */
        buildIndexProbe(v, nEq, pIdx);

#    May you find forgiveness for yourself and forgive others.
#    May you share freely, never taking more than you give.
#
#***********************************************************************
# This file implements regression tests for SQLite library.  The
# focus of this file is testing built-in functions.
#
# $Id: func.test,v 1.71 2007/11/28 22:36:41 drh Exp $

set testdir [file dirname $argv0]
source $testdir/tester.tcl

# Create a table to work with.
#
do_test func-0.0 {
................................................................................
do_test func-12.2 {
  execsql {
    SELECT test_destructor_count();
  }
} {0}
do_test func-12.3 {
  execsql {
    SELECT test_destructor('hello')||' world', test_destructor_count();
  }
} {{hello world} 0}
do_test func-12.4 {
  execsql {
    SELECT test_destructor_count();
  }
} {0}
do_test func-12.5 {
  execsql {

#    May you find forgiveness for yourself and forgive others.
#    May you share freely, never taking more than you give.
#
#***********************************************************************
# This file implements regression tests for SQLite library.  The
# focus of this file is testing built-in functions.
#
# $Id: func.test,v 1.72 2008/01/12 19:03:49 drh Exp $

set testdir [file dirname $argv0]
source $testdir/tester.tcl

# Create a table to work with.
#
do_test func-0.0 {
................................................................................
do_test func-12.2 {
  execsql {
    SELECT test_destructor_count();
  }
} {0}
do_test func-12.3 {
  execsql {
    SELECT test_destructor('hello')||' world'
  }
} {{hello world}}
do_test func-12.4 {
  execsql {
    SELECT test_destructor_count();
  }
} {0}
do_test func-12.5 {
  execsql {