SQLite

**    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 1.399 2008/10/11 16:47:36 drh Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>

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

  } 
  if( !pParse->nErr && pParse->nVar>db->aLimit[SQLITE_LIMIT_VARIABLE_NUMBER] ){
    sqlite3ErrorMsg(pParse, "too many SQL variables");
  }
}

/*
** Clear an expression structure without deleting the structure itself.
** Substructure is deleted.
*/
void sqlite3ExprClear(sqlite3 *db, Expr *p){

  if( p->span.dyn ) sqlite3DbFree(db, (char*)p->span.z);
  if( p->token.dyn ) sqlite3DbFree(db, (char*)p->token.z);
  sqlite3ExprDelete(db, p->pLeft);
  sqlite3ExprDelete(db, p->pRight);
  sqlite3ExprListDelete(db, p->pList);
  sqlite3SelectDelete(db, p->pSelect);
}

/*
** Recursively delete an expression tree.
*/
void sqlite3ExprDelete(sqlite3 *db, Expr *p){
  if( p==0 ) return;
  sqlite3ExprClear(db, p);
  sqlite3DbFree(db, p);
}

/*
** The Expr.token field might be a string literal that is quoted.
** If so, remove the quotation marks.
*/

**
*************************************************************************
**
** This file contains routines used for walking the parser tree and
** resolve all identifiers by associating them with a particular
** table and column.
**
** $Id: resolve.c,v 1.9 2008/10/11 16:47:36 drh Exp $
*/
#include "sqliteInt.h"
#include <stdlib.h>
#include <string.h>

/*
** Turn the pExpr expression into an alias for the iCol-th column of the

    }
    pDup->iTable = pEList->a[iCol].iAlias;
  }
  if( pExpr->flags & EP_ExpCollate ){
    pDup->pColl = pExpr->pColl;
    pDup->flags |= EP_ExpCollate;
  }
  sqlite3ExprClear(db, pExpr);

  memcpy(pExpr, pDup, sizeof(*pExpr));
  sqlite3DbFree(db, pDup);
}

/*
** Given the name of a column of the form X.Y.Z or Y.Z or just Z, look up
** that name in the set of source tables in pSrcList and make the pExpr 

/*
** 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 1.782 2008/10/11 16:47:36 drh Exp $
*/
#ifndef _SQLITEINT_H_
#define _SQLITEINT_H_

/*
** Include the configuration header output by 'configure' if we're using the
** autoconf-based build

Expr *sqlite3Expr(sqlite3*, int, Expr*, Expr*, const Token*);
Expr *sqlite3PExpr(Parse*, int, Expr*, Expr*, const Token*);
Expr *sqlite3RegisterExpr(Parse*,Token*);
Expr *sqlite3ExprAnd(sqlite3*,Expr*, Expr*);
void sqlite3ExprSpan(Expr*,Token*,Token*);
Expr *sqlite3ExprFunction(Parse*,ExprList*, Token*);
void sqlite3ExprAssignVarNumber(Parse*, Expr*);
void sqlite3ExprClear(sqlite3*, Expr*);
void sqlite3ExprDelete(sqlite3*, Expr*);
ExprList *sqlite3ExprListAppend(Parse*,ExprList*,Expr*,Token*);
void sqlite3ExprListDelete(sqlite3*, ExprList*);
int sqlite3Init(sqlite3*, char**);
int sqlite3InitCallback(void*, int, char**, char**);
void sqlite3Pragma(Parse*,Token*,Token*,Token*,int);
void sqlite3ResetInternalSchema(sqlite3*, int);

** This module contains C code that generates VDBE code used to process
** the WHERE clause of SQL statements.  This module is responsible 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 1.326 2008/10/11 16:47:36 drh Exp $
*/
#include "sqliteInt.h"

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

#endif /* SQLITE_TEST */


/*
** Free a WhereInfo structure
*/
static void whereInfoFree(sqlite3 *db, WhereInfo *pWInfo){
  if( pWInfo ){
    int i;

    for(i=0; i<pWInfo->nLevel; i++){
      sqlite3_index_info *pInfo = pWInfo->a[i].pIdxInfo;
      if( pInfo ){
        assert( pInfo->needToFreeIdxStr==0 );
        sqlite3DbFree(db, pInfo);
      }
    }

  pWInfo->iContinue = cont;
  whereClauseClear(&wc);
  return pWInfo;

  /* Jump here if malloc fails */
whereBeginError:
  whereClauseClear(&wc);
  whereInfoFree(db, pWInfo);
  return 0;
}

/*
** Generate the end of the WHERE loop.  See comments on 
** sqlite3WhereBegin() for additional information.
*/

        }
      }
    }
  }

  /* Final cleanup
  */
  whereInfoFree(db, pWInfo);
  return;
}