SQLite

**    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 1.250 2005/06/06 21:19:57 drh Exp $
*/
#include "sqliteInt.h"


/*
** Allocate a new Select structure and return a pointer to that
** structure.

      if( eDest==SRT_Callback ){
        generateColumnNames(pParse, 0, p->pEList);
      }
      iBreak = sqlite3VdbeMakeLabel(v);
      iCont = sqlite3VdbeMakeLabel(v);
      sqlite3VdbeAddOp(v, OP_Rewind, tab1, iBreak);
      computeLimitRegisters(pParse, p);
      iStart = sqlite3VdbeAddOp(v, OP_FullKey, tab1, 0);
      sqlite3VdbeAddOp(v, OP_NotFound, tab2, iCont);
      rc = selectInnerLoop(pParse, p, p->pEList, tab1, p->pEList->nExpr,
                             p->pOrderBy, -1, eDest, iParm, 
                             iCont, iBreak, 0);
      if( rc ){
        rc = 1;
        goto multi_select_end;

**
** 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 1.467 2005/06/06 17:27:19 drh Exp $
*/
#include "sqliteInt.h"
#include "os.h"
#include <ctype.h>
#include "vdbeInt.h"

/*

  assert( i>=0 && i<p->nCursor );
  assert( p->apCsr[i]!=0 );
  if( ((pC = p->apCsr[i])->pCursor!=0 || pC->pseudoTable) ){
    char *zKey;
    i64 nKey; 
    i64 iKey;
    if( pOp->opcode==OP_PutStrKey ){

      Stringify(pNos, db->enc);
      nKey = pNos->n;
      zKey = pNos->z;
    }else{
      assert( pNos->flags & MEM_Int );

      /* If the table is an INTKEY table, set nKey to the value of

      break;
    }else if( pC->keyAsData || pOp->opcode==OP_RowKey ){
      i64 n64;
      assert( !pC->intKey );
      sqlite3BtreeKeySize(pCrsr, &n64);
      n = n64;
    }else{

      sqlite3BtreeDataSize(pCrsr, &n);
    }
    pTos->n = n;
    if( n<=NBFS ){
      pTos->flags = MEM_Blob | MEM_Short;
      pTos->z = pTos->zShort;
    }else{
      char *z = sqliteMallocRaw( n );
      if( z==0 ) goto no_mem;
      pTos->flags = MEM_Blob | MEM_Dyn;
      pTos->xDel = 0;
      pTos->z = z;
    }
    if( pC->keyAsData || pOp->opcode==OP_RowKey ){

      sqlite3BtreeKey(pCrsr, 0, n, pTos->z);
    }else{

      sqlite3BtreeData(pCrsr, 0, n, pTos->z);
    }
#ifndef SQLITE_OMIT_TRIGGER
  }else if( pC->pseudoTable ){
    pTos->n = pC->nData;
    pTos->z = pC->pData;
    pTos->flags = MEM_Blob|MEM_Ephem;

    v = keyToInt(v);
  }
  pTos->i = v;
  pTos->flags = MEM_Int;
  break;
}

#ifndef SQLITE_OMIT_COMPOUND_SELECT
/* Opcode: FullKey P1 * *
**
** Extract the complete key from the record that cursor P1 is currently
** pointing to and push the key onto the stack as a string.
**
** Compare this opcode to Recno.  The Recno opcode extracts the first
** 4 bytes of the key and pushes those bytes onto the stack as an
** integer.  This instruction pushes the entire key as a string.
**
** This opcode may not be used on a pseudo-table.
*/
case OP_FullKey: {
  int i = pOp->p1;
  BtCursor *pCrsr;
  Cursor *pC;

  assert( i>=0 && i<p->nCursor );
  assert( p->apCsr[i]!=0 );
  assert( p->apCsr[i]->keyAsData );
  assert( !p->apCsr[i]->pseudoTable );
  pTos++;
  pTos->flags = MEM_Null;
  if( (pCrsr = (pC = p->apCsr[i])->pCursor)!=0 ){
    i64 amt;
    char *z;

    rc = sqlite3VdbeCursorMoveto(pC);
    if( rc ) goto abort_due_to_error;
    assert( pC->intKey==0 );
    sqlite3BtreeKeySize(pCrsr, &amt);
    if( amt<=0 ){
      rc = SQLITE_CORRUPT;
      goto abort_due_to_error;
    }
    if( amt>NBFS ){
      z = sqliteMallocRaw( amt );
      if( z==0 ) goto no_mem;
      pTos->flags = MEM_Blob | MEM_Dyn;
      pTos->xDel = 0;
    }else{
      z = pTos->zShort;
      pTos->flags = MEM_Blob | MEM_Short;
    }
    sqlite3BtreeKey(pCrsr, 0, amt, z);
    pTos->z = z;
    pTos->n = amt;
  }
  break;
}
#endif

/* Opcode: NullRow P1 * *
**
** Move the cursor P1 to a null row.  Any OP_Column operations
** that occur while the cursor is on the null row will always push 
** a NULL onto the stack.
*/
case OP_NullRow: {        /* no-push */