SQLite

/*
** 2005 July 8
**
** The author disclaims copyright to this source code.  In place of
** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains code associated with the ANALYZE command.
**
** @(#) $Id: analyze.c,v 1.35 2008/01/08 23:54:25 drh Exp $
*/
#ifndef SQLITE_OMIT_ANALYZE
#include "sqliteInt.h"

/*
** This routine generates code that opens the sqlite_stat1 table on cursor
** iStatCur.

    endOfLoop = sqlite3VdbeMakeLabel(v);
    sqlite3VdbeAddOp2(v, OP_Rewind, iIdxCur, endOfLoop);
    topOfLoop = sqlite3VdbeCurrentAddr(v);
    sqlite3VdbeAddOp2(v, OP_AddImm, iMem, 1);
    for(i=0; i<nCol; i++){
      sqlite3VdbeAddOp2(v, OP_Column, iIdxCur, i);
      sqlite3VdbeAddOp1(v, OP_SCopy, iMem+nCol+i+1);
      sqlite3VdbeAddOp0(v, OP_Ne );  /* Use Collating sequence */
      sqlite3VdbeChangeP5(v, SQLITE_JUMPIFNULL);
    }
    sqlite3VdbeAddOp2(v, OP_Goto, 0, endOfLoop);
    for(i=0; i<nCol; i++){
      addr = sqlite3VdbeAddOp2(v, OP_AddImm, iMem+i+1, 1);
      sqlite3VdbeChangeP2(v, topOfLoop + 3*i + 3, addr);
      sqlite3VdbeAddOp3(v, OP_Column, iIdxCur, i, iMem+nCol+i+1);
    }

**    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
** in order to generate code for DELETE FROM statements.
**
** $Id: delete.c,v 1.154 2008/01/08 23:54:25 drh Exp $
*/
#include "sqliteInt.h"

/*
** Look up every table that is named in pSrc.  If any table is not found,
** add an error message to pParse->zErrMsg and return NULL.  If all tables
** are found, return a pointer to the last table.

void sqlite3CodeInsert(Parse *p, int iCur, u8 flags){
  int iData = ++p->nMem;
  int iKey = ++p->nMem;
  Vdbe *v = sqlite3GetVdbe(p);
  sqlite3VdbeAddOp2(v, OP_Move, 0, iData);
  sqlite3VdbeAddOp2(v, OP_Move, 0, iKey);
  sqlite3VdbeAddOp3(v, OP_Insert, iCur, iData, iKey);
  sqlite3VdbeChangeP5(v, flags);
}

/*
** Allocate nVal contiguous memory cells and return the index of the
** first. Also pop nVal elements from the stack and store them in the 
** registers. The element on the top of the stack is stored in the
** register with the largest index.

**    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 1.338 2008/01/08 23:54:25 drh Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>

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

      return idx_affinity==SQLITE_AFF_TEXT;
    default:
      return sqlite3IsNumericAffinity(idx_affinity);
  }
}

/*
** Return the P5 value that should be used for a binary comparison
** opcode (OP_Eq, OP_Ge etc.) used to compare pExpr1 and pExpr2.



*/
static u8 binaryCompareP5(Expr *pExpr1, Expr *pExpr2, int jumpIfNull){
  u8 aff = (char)sqlite3ExprAffinity(pExpr2);
  aff = sqlite3CompareAffinity(pExpr1, aff) | jumpIfNull;
  return aff;
}

/*
** Return a pointer to the collation sequence that should be used by
** a binary comparison operator comparing pLeft and pRight.
**
** If the left hand expression has a collating sequence type, then it is

** Generate code for a comparison operator.
*/
static int codeCompare(
  Parse *pParse,    /* The parsing (and code generating) context */
  Expr *pLeft,      /* The left operand */
  Expr *pRight,     /* The right operand */
  int opcode,       /* The comparison opcode */
  int in1, int in2, /* Register holding operands */
  int dest,         /* Jump here if true.  */
  int jumpIfNull    /* If true, jump if either operand is NULL */
){
  int p5;
  int addr;
  CollSeq *p4;

  p4 = sqlite3BinaryCompareCollSeq(pParse, pLeft, pRight);
  p5 = binaryCompareP5(pLeft, pRight, jumpIfNull);
  addr = sqlite3VdbeAddOp4(pParse->pVdbe, opcode, in2, dest, in1,
                           (void*)p4, P4_COLLSEQ);
  sqlite3VdbeChangeP5(pParse->pVdbe, p5);
  return addr;
}

/*
** Construct a new expression node and return a pointer to it.  Memory
** for this node is obtained from sqlite3_malloc().  The calling function
** is responsible for making sure the node eventually gets freed.
*/

#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_STAR:
    case TK_MINUS:

#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;

      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: {

        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 = sqlite3VdbeAddOp2(v, OP_IfNot, 1, 0);
        }
        sqlite3ExprCode(pParse, aListelem[i+1].pExpr, target);
        sqlite3VdbeAddOp2(v, OP_Goto, 0, expr_end_label);
        sqlite3VdbeJumpHere(v, jumpInst);

/*
** Generate code for a boolean expression such that a jump is made
** to the label "dest" if the expression is true but execution
** continues straight thru if the expression is false.
**
** If the expression evaluates to NULL (neither true nor false), then
** take the jump if the jumpIfNull flag is SQLITE_JUMPIFNULL.
**
** 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.
*/
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);
      sqlite3ExprIfTrue(pParse, pExpr->pRight, dest, jumpIfNull);
      sqlite3VdbeResolveLabel(v, d2);
      break;
    }
    case TK_OR: {
      sqlite3ExprIfTrue(pParse, pExpr->pLeft, dest, jumpIfNull);
      sqlite3ExprIfTrue(pParse, pExpr->pRight, dest, jumpIfNull);

      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);

      */
      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);
      sqlite3VdbeAddOp2(v, OP_If, jumpIfNull, dest);
      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
  **       ---------          ----------
  **       TK_ISNULL          OP_NotNull

    case TK_AND: {
      sqlite3ExprIfFalse(pParse, pExpr->pLeft, dest, jumpIfNull);
      sqlite3ExprIfFalse(pParse, pExpr->pRight, dest, jumpIfNull);
      break;
    }
    case TK_OR: {
      int d2 = sqlite3VdbeMakeLabel(v);
      sqlite3ExprIfTrue(pParse, pExpr->pLeft, d2, jumpIfNull^SQLITE_JUMPIFNULL);
      sqlite3ExprIfFalse(pParse, pExpr->pRight, dest, jumpIfNull);
      sqlite3VdbeResolveLabel(v, d2);
      break;
    }
    case TK_NOT: {
      sqlite3ExprIfTrue(pParse, pExpr->pLeft, dest, jumpIfNull);
      break;
    }
    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;

      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);
      sqlite3VdbeAddOp2(v, OP_IfNot, jumpIfNull, dest);
      break;
    }

**    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 INSERT statements in SQLite.
**
** $Id: insert.c,v 1.218 2008/01/08 23:54:25 drh Exp $
*/
#include "sqliteInt.h"

/*
** Set P4 of the most recently inserted opcode to a column affinity
** string for index pIdx. A column affinity string has one character
** for each column in the table, according to the affinity of the column:

    memId = ++pParse->nMem;
    pParse->nMem++;
    sqlite3OpenTable(pParse, iCur, iDb, pDb->pSchema->pSeqTab, OP_OpenRead);
    addr = sqlite3VdbeCurrentAddr(v);
    sqlite3VdbeAddOp2(v, OP_Rewind, iCur, addr+8);
    sqlite3VdbeAddOp2(v, OP_Column, iCur, 0);
    sqlite3VdbeAddOp4(v, OP_String8, 0, 0, 0, pTab->zName, 0);
    sqlite3VdbeAddOp2(v, OP_Ne, 0, addr+7);
    sqlite3VdbeChangeP5(v, SQLITE_JUMPIFNULL);
    sqlite3VdbeAddOp2(v, OP_Rowid, iCur, memId+1);
    sqlite3VdbeAddOp3(v, OP_Column, iCur, 1, memId);
    sqlite3VdbeAddOp2(v, OP_Goto, 0, addr+8);
    sqlite3VdbeAddOp2(v, OP_Next, iCur, addr+1);
    sqlite3VdbeAddOp2(v, OP_Close, iCur, 0);
  }
  return memId;

    sqlite3OpenTable(pParse, iCur, iDb, pDb->pSchema->pSeqTab, OP_OpenWrite);
    j1 = sqlite3VdbeAddOp1(v, OP_NotNull, memId+1);
    sqlite3VdbeAddOp2(v, OP_NewRowid, iCur, memId+1);
    sqlite3VdbeJumpHere(v, j1);
    sqlite3VdbeAddOp4(v, OP_String8, 0, memId-1, 0, pTab->zName, 0);
    sqlite3VdbeAddOp3(v, OP_RegMakeRec, memId-1, 2, memId-1);
    sqlite3VdbeAddOp3(v, OP_Insert, iCur, memId-1, memId+1);
    sqlite3VdbeChangeP5(v, OPFLAG_APPEND);
    sqlite3VdbeAddOp1(v, OP_Close, iCur);
  }
}
#else
/*
** If SQLITE_OMIT_AUTOINCREMENT is defined, then the three routines
** above are all no-ops

  /* Test all CHECK constraints
  */
#ifndef SQLITE_OMIT_CHECK
  if( pTab->pCheck && (pParse->db->flags & SQLITE_IgnoreChecks)==0 ){
    int allOk = sqlite3VdbeMakeLabel(v);
    pParse->ckBase = regData;
    sqlite3ExprIfTrue(pParse, pTab->pCheck, allOk, SQLITE_JUMPIFNULL);
    onError = overrideError!=OE_Default ? overrideError : OE_Abort;
    if( onError==OE_Ignore ){
      sqlite3VdbeAddOp2(v, OP_Goto, 0, ignoreDest);
    }else{
      sqlite3VdbeAddOp2(v, OP_Halt, SQLITE_CONSTRAINT, onError);
    }
    sqlite3VdbeResolveLabel(v, allOk);

**    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 1.393 2008/01/08 23:54:25 drh Exp $
*/
#include "sqliteInt.h"


/*
** Delete all the content of a Select structure but do not deallocate
** the select structure itself.

      sqlite3VdbeAddOp2(v, OP_Return, 0, 0);
      addrOutputRow = sqlite3VdbeCurrentAddr(v);
      sqlite3VdbeAddOp2(v, OP_IfMemPos, iUseFlag, addrOutputRow+2);
      VdbeComment((v, "Groupby result generator entry point"));
      sqlite3VdbeAddOp2(v, OP_Return, 0, 0);
      finalizeAggFunctions(pParse, &sAggInfo);
      if( pHaving ){
        sqlite3ExprIfFalse(pParse, pHaving, addrOutputRow+1, SQLITE_JUMPIFNULL);
      }
      rc = selectInnerLoop(pParse, p, p->pEList, 0, 0, pOrderBy,
                           distinct, pDest,
                           addrOutputRow+1, addrSetAbort, aff);
      if( rc ){
        goto select_end;
      }

      }
      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
      ** block.  If there were no changes, this block is skipped.
      **
      ** This code copies current group by terms in b0,b1,b2,...

        sqlite3VdbeAddOp2(v, OP_Goto, 0, pWInfo->iBreak);
        VdbeComment((v, "%s() by index", (flag==ORDERBY_MIN?"min":"max")));
      }
      sqlite3WhereEnd(pWInfo);
      finalizeAggFunctions(pParse, &sAggInfo);
      pOrderBy = 0;
      if( pHaving ){
        sqlite3ExprIfFalse(pParse, pHaving, addrEnd, SQLITE_JUMPIFNULL);
      }
      selectInnerLoop(pParse, p, p->pEList, 0, 0, 0, -1, 
                      pDest, addrEnd, addrEnd, aff);

      sqlite3ExprListDelete(pDel);
    }
    sqlite3VdbeResolveLabel(v, addrEnd);

/*
** 2001 September 15
**
** The author disclaims copyright to this source code.  In place of
** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** Internal interface definitions for SQLite.
**
** @(#) $Id: sqliteInt.h,v 1.644 2008/01/08 23:54:25 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

#define SQLITE_AFF_NONE     'b'
#define SQLITE_AFF_NUMERIC  'c'
#define SQLITE_AFF_INTEGER  'd'
#define SQLITE_AFF_REAL     'e'

#define sqlite3IsNumericAffinity(X)  ((X)>=SQLITE_AFF_NUMERIC)

/*
** The SQLITE_AFF_MASK values masks off the significant bits of an
** affinity value. 
*/
#define SQLITE_AFF_MASK     0x67

/*
** Additional bit values that can be ORed with an affinity without
** changing the affinity.
*/
#define SQLITE_JUMPIFNULL   0x08  /* jumps if either operand is NULL */
#define SQLITE_NULLEQUAL    0x10  /* compare NULLs equal */
#define SQLITE_STOREP2      0x80  /* Store result in reg[P2] rather than jump */

/*
** Each SQL table is represented in memory by an instance of the
** following structure.
**
** Table.zName is the name of the table.  The case of the original
** CREATE TABLE statement is stored, but case is not significant for
** comparisons.

      endTrigger = sqlite3VdbeMakeLabel(pParse->pVdbe);
      whenExpr = sqlite3ExprDup(db, p->pWhen);
      if( db->mallocFailed || sqlite3ExprResolveNames(&sNC, whenExpr) ){
        pParse->trigStack = trigStackEntry.pNext;
        sqlite3ExprDelete(whenExpr);
        return 1;
      }
      sqlite3ExprIfFalse(pParse, whenExpr, endTrigger, SQLITE_JUMPIFNULL);
      sqlite3ExprDelete(whenExpr);

      codeTriggerProgram(pParse, p->step_list, orconf); 

      /* Pop the entry off the trigger stack */
      pParse->trigStack = trigStackEntry.pNext;
      sqlite3AuthContextPop(&sContext);

**
** 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 1.689 2008/01/08 23:54:25 drh Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>
#include "vdbeInt.h"

/*
** The following global variable is incremented every time a cursor

    assert( pTos->flags & (MEM_Str|MEM_Blob) );
    assert( pTos->z==pTos[-pOp->p1].zShort );
    pTos->z = pTos->zShort;
  }
  break;
}
















/* Opcode: Callback P1 * *
**
** The top P1 values on the stack represent a single result row from
** a query.  This opcode causes the sqlite3_step() call to terminate
** with an SQLITE_ROW return code and it sets up the sqlite3_stmt
** structure to provide access to the top P1 values as the result
** row.  When the sqlite3_step() function is run again, the top P1

  if( (pIn1->flags & MEM_Null)==0 ){
    sqlite3VdbeMemRealify(pIn1);
  }
  break;
}
#endif /* SQLITE_OMIT_CAST */

/* Opcode: Lt P1 P2 P3 P4 P5
**
** Compare the values in register P1 and P3.  If reg(P3)<reg(P1) then
** jump to address P2.  
**
** If the SQLITE_JUMPIFNULL bit of P5 is set and either reg(P1) or
** reg(P3) is NULL then take the jump.  If the SQLITE_JUMPIFNULL 
** bit is clear then fall thru if either operand is NULL.

**
** If the SQLITE_NULLEQUAL bit of P5 is set then treat NULL operands
** as being equal to one another.  Normally NULLs are not equal to 
** anything including other NULLs.



**
** The SQLITE_AFF_MASK portion of P5 must be an affinity character -
** SQLITE_AFF_TEXT, SQLITE_AFF_INTEGER, and so forth. An attempt is made 
** to coerce both operands according to this affinity before the
** comparison is made. If the SQLITE_AFF_MASK is 0x00, then numeric
** affinity is used.
**
** Once any conversions have taken place, and neither value is NULL, 
** the values are compared. If both values are blobs then memcmp() is
** used to determine the results of the comparison.  If both values
** are text, then the appropriate collating function specified in
** P4 is  used to do the comparison.  If P4 is not specified then
** memcmp() is used to compare text string.  If both values are
** numeric, then a numeric comparison is used. If the two values
** are of different types, then numbers are considered less than
** strings and strings are considered less than blobs.
**
** If the SQLITE_STOREP2 bit of P5 is set, then do not jump.  Instead,

** store a boolean result (either 0, or 1, or NULL) in register P2.



*/
/* Opcode: Ne P1 P2 P4
**
** This works just like the Lt opcode except that the jump is taken if
** the operands in registers P1 and P3 are not equal.  See the Lt opcode for
** additional information.
*/
/* Opcode: Eq P1 P2 P4
**
** This works just like the Lt opcode except that the jump is taken if
** the operands in registers P1 and P3 are equal.
** See the Lt opcode for additional information.
*/
/* Opcode: Le P1 P2 P4
**
** This works just like the Lt opcode except that the jump is taken if
** the content of register P3 is less than or equal to the content of
** register P1.  See the Lt opcode for additional information.
*/
/* Opcode: Gt P1 P2 P4
**
** This works just like the Lt opcode except that the jump is taken if
** the content of register P3 is greater than the content of
** register P1.  See the Lt opcode for additional information.
*/
/* Opcode: Ge P1 P2 P4
**
** This works just like the Lt opcode except that the jump is taken if
** the content of register P3 is greater than or equal to the content of
** register P1.  See the Lt opcode for additional information.
*/
case OP_Eq:               /* same as TK_EQ, no-push, jump, in1, in3 */
case OP_Ne:               /* same as TK_NE, no-push, jump, in1, in3 */
case OP_Lt:               /* same as TK_LT, no-push, jump, in1, in3 */
case OP_Le:               /* same as TK_LE, no-push, jump, in1, in3 */
case OP_Gt:               /* same as TK_GT, no-push, jump, in1, in3 */
case OP_Ge: {             /* same as TK_GE, no-push, jump, in1, in3 */

  int flags;
  int res;
  char affinity;
  Mem x1, x3;


  flags = pIn1->flags|pIn3->flags;

  /* If either value is a NULL P2 is not zero, take the jump if the least
  ** significant byte of P1 is true. If P2 is zero, then push a NULL onto
  ** the stack.
  */
  if( flags&MEM_Null ){
    if( (pOp->p5 & SQLITE_NULLEQUAL)!=0 ){
      /*



      ** When SQLITE_NULLEQUAL set and either operand is NULL
      ** then both operands are converted to integers prior to being 
      ** passed down into the normal comparison logic below.  
      ** NULL operands are converted to zero and non-NULL operands
      ** are converted to 1.  Thus, for example, with SQLITE_NULLEQUAL
      ** set,  NULL==NULL is true whereas it would normally NULL.
      ** Similarly,  NULL!=123 is true.
      */
      x1.flags = MEM_Int;
      x1.u.i = (pIn1->flags & MEM_Null)==0;
      pIn1 = &x1;
      x3.flags = MEM_Int;
      x3.u.i = (pIn3->flags & MEM_Null)==0;
      pIn3 = &x3;
    }else{
      /* If the SQLITE_NULLEQUAL bit is clear and either operand is NULL then
      ** the result is always NULL.  The jump is taken if the 
      ** SQLITE_JUMPIFNULL bit is set.
      */

      if( pOp->p5 & SQLITE_STOREP2 ){
        pOut = &p->aMem[pOp->p2];
        Release(pOut);
        pOut->flags = MEM_Null;
        REGISTER_TRACE(pOp->p2, pOut);
      }else if( pOp->p5 & SQLITE_JUMPIFNULL ){
        pc = pOp->p2-1;




      }
      break;
    }
  }

  affinity = pOp->p5 & SQLITE_AFF_MASK;
  if( affinity ){
    applyAffinity(pIn1, affinity, encoding);
    applyAffinity(pIn3, affinity, encoding);
  }

  assert( pOp->p4type==P4_COLLSEQ || pOp->p4.pColl==0 );
  ExpandBlob(pIn1);
  ExpandBlob(pIn3);
  res = sqlite3MemCompare(pIn3, pIn1, pOp->p4.pColl);
  switch( pOp->opcode ){
    case OP_Eq:    res = res==0;     break;
    case OP_Ne:    res = res!=0;     break;
    case OP_Lt:    res = res<0;      break;
    case OP_Le:    res = res<=0;     break;
    case OP_Gt:    res = res>0;      break;
    default:       res = res>=0;     break;
  }


  if( pOp->p5 & SQLITE_STOREP2 ){

    pOut = &p->aMem[pOp->p2];

    Release(pOut);

    pOut->flags = MEM_Int;
    pOut->u.i = res;
    REGISTER_TRACE(pOp->p2, pOut);
  }else if( res ){
    pc = pOp->p2-1;
  }
  break;
}

/* Opcode: And P1 P2 P3 * *
**
** Take the logical AND of the values in registers P1 and P2 and

*************************************************************************
** Header file for the Virtual DataBase Engine (VDBE)
**
** This header defines the interface to the virtual database engine
** or VDBE.  The VDBE implements an abstract machine that runs a
** simple program to access and modify the underlying database.
**
** $Id: vdbe.h,v 1.123 2008/01/08 23:54:25 drh Exp $
*/
#ifndef _SQLITE_VDBE_H_
#define _SQLITE_VDBE_H_
#include <stdio.h>

/*
** A single VDBE is an opaque structure named "Vdbe".  Only routines

int sqlite3VdbeAddOp2(Vdbe*,int,int,int);
int sqlite3VdbeAddOp3(Vdbe*,int,int,int,int);
int sqlite3VdbeAddOp4(Vdbe*,int,int,int,int,const char *zP4,int);
int sqlite3VdbeAddOpList(Vdbe*, int nOp, VdbeOpList const *aOp);
void sqlite3VdbeChangeP1(Vdbe*, int addr, int P1);
void sqlite3VdbeChangeP2(Vdbe*, int addr, int P2);
void sqlite3VdbeChangeP3(Vdbe*, int addr, int P3);
void sqlite3VdbeChangeP5(Vdbe*, u8 P5);
void sqlite3VdbeJumpHere(Vdbe*, int addr);
void sqlite3VdbeChangeToNoop(Vdbe*, int addr, int N);
void sqlite3VdbeChangeP4(Vdbe*, int addr, const char *zP4, int N);
void sqlite3VdbeUsesBtree(Vdbe*, int);
VdbeOp *sqlite3VdbeGetOp(Vdbe*, int);
int sqlite3VdbeMakeLabel(Vdbe*);
void sqlite3VdbeDelete(Vdbe*);

  assert( p==0 || p->magic==VDBE_MAGIC_INIT );
  if( p && addr>=0 && p->nOp>addr && p->aOp ){
    p->aOp[addr].p3 = val;
  }
}

/*
** Change the value of the P5 operand for the most recently
** added operation.
*/
void sqlite3VdbeChangeP5(Vdbe *p, u8 val){
  assert( p==0 || p->magic==VDBE_MAGIC_INIT );
  if( p && p->aOp ){
    assert( p->nOp>0 );
    p->aOp[p->nOp-1].p5 = val;
  }
}

/*
** Change the P2 operand of instruction addr so that it points to
** the address of the next instruction to be coded.
*/

** 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 1.278 2008/01/08 23:54:26 drh Exp $
*/
#include "sqliteInt.h"

/*
** The number of bits in a Bitmask.  "BMS" means "BitMask Size".
*/
#define BMS  (sizeof(Bitmask)*8)

  pWInfo->pTabList = pTabList;
  pWInfo->iBreak = sqlite3VdbeMakeLabel(v);

  /* Special case: a WHERE clause that is constant.  Evaluate the
  ** expression and either jump over all of the code or fall thru.
  */
  if( pWhere && (pTabList->nSrc==0 || sqlite3ExprIsConstantNotJoin(pWhere)) ){
    sqlite3ExprIfFalse(pParse, pWhere, pWInfo->iBreak, SQLITE_JUMPIFNULL);
    pWhere = 0;
  }

  /* Analyze all of the subexpressions.  Note that exprAnalyze() might
  ** add new virtual terms onto the end of the WHERE clause.  We do not
  ** want to analyze these virtual terms, so start analyzing at the end
  ** and work forward so that the added virtual terms are never processed.

      start = sqlite3VdbeCurrentAddr(v);
      pLevel->op = bRev ? OP_Prev : OP_Next;
      pLevel->p1 = iCur;
      pLevel->p2 = start;
      if( testOp!=OP_Noop ){
        sqlite3VdbeAddOp2(v, OP_Rowid, iCur, 0);
        sqlite3VdbeAddOp2(v, OP_SCopy, pLevel->iMem, 0);
        sqlite3VdbeAddOp2(v, testOp, 0, brk);
        sqlite3VdbeChangeP5(v, SQLITE_AFF_NUMERIC | SQLITE_JUMPIFNULL);
      }
    }else if( pLevel->flags & WHERE_COLUMN_RANGE ){
      /* Case 3: The WHERE clause term that refers to the right-most
      **         column of the index is an inequality.  For example, if
      **         the index is on (x,y,z) and the WHERE clause is of the
      **         form "x=5 AND y<10" then this case is used.  Only the
      **         right-most column can be an inequality - the rest must

      if( pTerm->flags & (TERM_VIRTUAL|TERM_CODED) ) continue;
      if( (pTerm->prereqAll & notReady)!=0 ) continue;
      pE = pTerm->pExpr;
      assert( pE!=0 );
      if( pLevel->iLeftJoin && !ExprHasProperty(pE, EP_FromJoin) ){
        continue;
      }
      sqlite3ExprIfFalse(pParse, pE, cont, SQLITE_JUMPIFNULL);
      pTerm->flags |= TERM_CODED;
    }

    /* For a LEFT OUTER JOIN, generate code that will record the fact that
    ** at least one row of the right table has matched the left table.  
    */
    if( pLevel->iLeftJoin ){
      pLevel->top = sqlite3VdbeCurrentAddr(v);
      sqlite3VdbeAddOp2(v, OP_Integer, 1, pLevel->iLeftJoin);
      VdbeComment((v, "record LEFT JOIN hit"));
      for(pTerm=wc.a, j=0; j<wc.nTerm; j++, pTerm++){
        if( pTerm->flags & (TERM_VIRTUAL|TERM_CODED) ) continue;
        if( (pTerm->prereqAll & notReady)!=0 ) continue;
        assert( pTerm->pExpr );
        sqlite3ExprIfFalse(pParse, pTerm->pExpr, cont, SQLITE_JUMPIFNULL);
        pTerm->flags |= TERM_CODED;
      }
    }
  }

#ifdef SQLITE_TEST  /* For testing and debugging use only */
  /* Record in the query plan information about the current table