SQLite

**
*************************************************************************
** Main file for the SQLite library.  The routines in this file
** implement the programmer interface to the library.  Routines in
** other files are for internal use by SQLite and should not be
** accessed by users of the library.
**
** $Id: main.c,v 1.9 2000/06/05 16:01:39 drh Exp $
*/
#include "sqliteInt.h"

/*
** This is the callback routine for the code that initializes the
** database.  Each callback contains text of a CREATE TABLE or
** CREATE INDEX statement that must be parsed to yield the internal
** structures that describe the tables.
*/
static int sqliteOpenCb(void *pDb, int argc, char **argv, char **azColName){
  sqlite *db = (sqlite*)pDb;
  Parse sParse;
  int nErr;


  if( argc!=1 ) return 0;
  memset(&sParse, 0, sizeof(sParse));
  sParse.db = db;
  sParse.initFlag = 1;
  nErr = sqliteRunParser(&sParse, argv[0], 0);
  return nErr;

**
*************************************************************************
** This file contains SQLite's grammar for SQL.  Process this file
** using the lemon parser generator to generate C code that runs
** the parser.  Lemon will also generate a header file containing
** numeric codes for all of the tokens.
**
** @(#) $Id: parse.y,v 1.9 2000/06/05 16:01:39 drh Exp $
*/
%token_prefix TK_
%token_type {Token}
%extra_argument {Parse *pParse}
%syntax_error {
  sqliteSetNString(&pParse->zErrMsg,"syntax error near \"",0,TOKEN.z,TOKEN.n,
                   "\"", 1, 0);

// The next command format is dropping tables.
//
cmd ::= DROP TABLE id(X).          {sqliteDropTable(pParse,&X);}

// The select statement
//
cmd ::= select(X).  {

  sqliteSelect(pParse, X, 0, 0);
  sqliteSelectDelete(X);
}

%type select {Select*}
%destructor select {sqliteSelectDelete($$);}

select(A) ::= SELECT distinct(D) selcollist(W) from(X) where_opt(Y)
              orderby_opt(Z). {
  A = sqliteSelectNew(W,X,Y,0,0,Z,D);
}

// The "distinct" nonterminal is true (1) if the DISTINCT keyword is
// present and false (0) if it is not.
//
%type distinct {int}
distinct(A) ::= DISTINCT.   {A = 1;}
distinct(A) ::= .           {A = 0;}

// selcollist is a list of expressions that are to become the return
// values of the SELECT statement.  In the case of "SELECT * FROM ..."
// the selcollist value is NULL.  
//
%type selcollist {ExprList*}
%destructor selcollist {sqliteExprListDelete($$);}
%type sclp {ExprList*}
%destructor sclp {sqliteExprListDelete($$);}

sclp(A) ::= selcollist(X) COMMA.             {A = X;}
sclp(A) ::= .                                {A = 0;}
selcollist(A) ::= STAR.                      {A = 0;}
selcollist(A) ::= sclp(P) expr(X).           {A = sqliteExprListAppend(P,X,0);}
selcollist(A) ::= sclp(P) expr(X) as ID(Y).  {A = sqliteExprListAppend(P,X,&Y);}
selcollist(A) ::= sclp(P) expr(X) as STRING(Y).
  {A = sqliteExprListAppend(P,X,&Y);}
as ::= .
as ::= AS.


%type seltablist {IdList*}
%destructor seltablist {sqliteIdListDelete($$);}
%type stl_prefix {IdList*}
%destructor stl_prefix {sqliteIdListDelete($$);}
%type from {IdList*}
%destructor from {sqliteIdListDelete($$);}

%type sortlist {ExprList*}
%destructor sortlist {sqliteExprListDelete($$);}
%type sortitem {Expr*}
%destructor sortitem {sqliteExprDelete($$);}

orderby_opt(A) ::= .                          {A = 0;}
orderby_opt(A) ::= ORDER BY sortlist(X).      {A = X;}
sortlist(A) ::= sortlist(X) COMMA sortitem(Y) sortorder(Z). {

  A = sqliteExprListAppend(X,Y,0);
  A->a[A->nExpr-1].idx = Z;       /* 0 for ascending order, 1 for decending */
}
sortlist(A) ::= sortitem(Y) sortorder(Z). {

  A = sqliteExprListAppend(0,Y,0);
  A->a[0].idx = Z;
}
sortitem(A) ::= expr(X).   {A = X;}

%type sortorder {int}

sortorder(A) ::= ASC.      {A = 0;}
sortorder(A) ::= DESC.     {A = 1;}
sortorder(A) ::= .         {A = 0;}

**   drh@hwaci.com
**   http://www.hwaci.com/drh/
**
*************************************************************************
** This file contains C code routines that are called by the parser
** to handle SELECT statements.
**
** $Id: select.c,v 1.7 2000/06/05 16:01:39 drh Exp $
*/
#include "sqliteInt.h"


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

  ExprList *pEList,
  IdList *pSrc,
  Expr *pWhere,
  ExprList *pGroupBy,
  Expr *pHaving,
  ExprList *pOrderBy,
  int isDistinct
){
  Select *pNew;
  pNew = sqliteMalloc( sizeof(*pNew) );
  if( pNew==0 ) return 0;
  pNew->pEList = pEList;
  pNew->pSrc = pSrc;
  pNew->pWhere = pWhere;
  pNew->pGroupBy = pGroupBy;
  pNew->pHaving = pHaving;
  pNew->pOrderBy = pOrderBy;
  pNew->isDistinct = isDistinct;
  return pNew;
}

/*
** Delete the given Select structure and all of its substructures.
*/
void sqliteSelectDelete(Select *p){
  sqliteExprListDelete(p->pEList);
  sqliteIdListDelete(p->pSrc);
  sqliteExprDelete(p->pWhere);
  sqliteExprListDelete(p->pGroupBy);
  sqliteExprDelete(p->pHaving);
  sqliteExprListDelete(p->pOrderBy);
  sqliteFree(p);
}

/*
** Generate code for the given SELECT statement.
**
** If pDest==0 and iMem<0, then the results of the query are sent to
** the callback function.  If pDest!=0 then the results are written to
** the single table specified.  If pDest==0 and iMem>=0 then the result
** should be a single value which is then stored in memory location iMem
** of the virtual machine.
**
** This routine returns the number of errors.  If any errors are
** encountered, then an appropriate error message is left in
** pParse->zErrMsg.
**
** This routine does NOT free the Select structure passed in.  The
** calling function needs to do that.
*/
int sqliteSelect(
  Parse *pParse,         /* The parser context */
  Select *p,             /* The SELECT statement being coded. */
  Table *pDest,          /* Write results here, if not NULL */
  int iMem               /* Save result in this memory location, if >=0 */
){
  int i, j;
  WhereInfo *pWInfo;
  Vdbe *v;
  int isAgg = 0;         /* True for select lists like "count(*)" */
  ExprList *pEList;      /* List of fields to extract.  NULL means "*" */
  IdList *pTabList;      /* List of tables to select from */
  Expr *pWhere;          /* The WHERE clause.  May be NULL */
  ExprList *pOrderBy;    /* The ORDER BY clause.  May be NULL */
  int distinct;          /* If true, only output distinct results */


  pEList = p->pEList;
  pTabList = p->pSrc;
  pWhere = p->pWhere;
  pOrderBy = p->pOrderBy;
  distinct = p->isDistinct;

  /* 
  ** Do not even attempt to generate any code if we have already seen
  ** errors before this routine starts.
  */
  if( pParse->nErr>0 ) return 0;

  /* Look up every table in the table list.
  */
  for(i=0; i<pTabList->nId; i++){
    pTabList->a[i].pTab = sqliteFindTable(pParse->db, pTabList->a[i].zName);
    if( pTabList->a[i].pTab==0 ){
      sqliteSetString(&pParse->zErrMsg, "no such table: ", 
         pTabList->a[i].zName, 0);
      pParse->nErr++;
      return 1;
    }
  }

  /* If the list of fields to retrieve is "*" then replace it with
  ** a list of all fields from all tables.
  */
  if( pEList==0 ){

    }
  }

  /* Resolve the field names and do a semantics check on all the expressions.
  */
  for(i=0; i<pEList->nExpr; i++){
    if( sqliteExprResolveIds(pParse, pTabList, pEList->a[i].pExpr) ){
      return 1;
    }
    if( sqliteExprCheck(pParse, pEList->a[i].pExpr, 1, &pEList->a[i].isAgg) ){
      return 1;
    }
  }
  if( pEList->nExpr>0 ){
    isAgg = pEList->a[0].isAgg;
    for(i=1; i<pEList->nExpr; i++){
      if( pEList->a[i].isAgg!=isAgg ){
        sqliteSetString(&pParse->zErrMsg, "some selected items are aggregates "
          "and others are not", 0);
        pParse->nErr++;
        return 1;
      }
    }
  }
  if( pWhere ){
    if( sqliteExprResolveIds(pParse, pTabList, pWhere) ){
      return 1;
    }
    if( sqliteExprCheck(pParse, pWhere, 0, 0) ){
      return 1;
    }
  }
  if( pOrderBy ){
    for(i=0; i<pOrderBy->nExpr; i++){
      if( sqliteExprResolveIds(pParse, pTabList, pOrderBy->a[i].pExpr) ){
        return 1;
      }
      if( sqliteExprCheck(pParse, pOrderBy->a[i].pExpr, 0, 0) ){
        return 1;
      }
    }
  }

  /* ORDER BY is ignored if this is an aggregate query like count(*)
  ** since only one row will be returned.
  */
  if( isAgg && pOrderBy ){

    pOrderBy = 0;
  }

  /* Turn off distinct if this is an aggregate
  */
  if( isAgg ){
    distinct = 0;
  }

  /* Begin generating code.
  */
  v = pParse->pVdbe;
  if( v==0 ){
    v = pParse->pVdbe = sqliteVdbeCreate(pParse->db->pBe);
  }
  if( v==0 ){
    sqliteSetString(&pParse->zErrMsg, "out of memory", 0);
    pParse->nErr++;
    return 1;
  }
  if( pOrderBy ){
    sqliteVdbeAddOp(v, OP_SortOpen, 0, 0, 0, 0);
  }

  /* Identify column names
  */
  sqliteVdbeAddOp(v, OP_ColumnCount, pEList->nExpr, 0, 0, 0);

  /* Begin the database scan
  */
  if( distinct ){
    distinct = pTabList->nId*2+1;
    sqliteVdbeAddOp(v, OP_Open, distinct, 1, 0, 0);
  }
  pWInfo = sqliteWhereBegin(pParse, pTabList, pWhere, 0);
  if( pWInfo==0 ) return 1;

  /* Pull the requested fields.
  */
  if( !isAgg ){
    for(i=0; i<pEList->nExpr; i++){
      sqliteExprCode(pParse, pEList->a[i].pExpr);
    }

  ** right away.  If there is an ORDER BY, then we need to put the
  ** data into an appropriate sorter record.
  */
  if( pOrderBy ){
    char *zSortOrder;
    sqliteVdbeAddOp(v, OP_SortMakeRec, pEList->nExpr, 0, 0, 0);
    zSortOrder = sqliteMalloc( pOrderBy->nExpr + 1 );
    if( zSortOrder==0 ) return 1;
    for(i=0; i<pOrderBy->nExpr; i++){
      zSortOrder[i] = pOrderBy->a[i].idx ? '-' : '+';
      sqliteExprCode(pParse, pOrderBy->a[i].pExpr);
    }
    zSortOrder[pOrderBy->nExpr] = 0;
    sqliteVdbeAddOp(v, OP_SortMakeKey, pOrderBy->nExpr, 0, zSortOrder, 0);
    sqliteVdbeAddOp(v, OP_SortPut, 0, 0, 0, 0);

  /* If this is an aggregate, then we need to invoke the callback
  ** exactly once.
  */
  if( isAgg ){
    sqliteVdbeAddOp(v, OP_Callback, pEList->nExpr, 0, 0, 0);
  }









  return 0;
}

** Author contact information:
**   drh@hwaci.com
**   http://www.hwaci.com/drh/
**
*************************************************************************
** Internal interface definitions for SQLite.
**
** @(#) $Id: sqliteInt.h,v 1.14 2000/06/05 16:01:39 drh Exp $
*/
#include "sqlite.h"
#include "dbbe.h"
#include "vdbe.h"
#include "parse.h"
#include <gdbm.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>

#define MEMORY_DEBUG 1
#ifdef MEMORY_DEBUG
# define sqliteMalloc(X)    sqliteMalloc_(X,__FILE__,__LINE__)
# define sqliteFree(X)      sqliteFree_(X,__FILE__,__LINE__)
# define sqliteRealloc(X,Y) sqliteRealloc_(X,Y,__FILE__,__LINE__)
  void sqliteStrRealloc(char**);
#else
# define sqliteStrRealloc(X)

typedef struct Instruction Instruction;
typedef struct Expr Expr;
typedef struct ExprList ExprList;
typedef struct Parse Parse;
typedef struct Token Token;
typedef struct IdList IdList;
typedef struct WhereInfo WhereInfo;
typedef struct Select Select;

/*
** Each database is an instance of the following structure
*/
struct sqlite {
  Dbbe *pBe;                 /* The backend driver */
  int flags;                 /* Miscellanous flags */

struct WhereInfo {
  Parse *pParse;
  IdList *pTabList;
  int iContinue;
  int iBreak;
};

/*
** An instance of the following structure contains all information
** needed to generate code for a single SELECT statement.
*/
struct Select {
  int isDistinct;        /* True if the DISTINCT keyword is present */
  ExprList *pEList;      /* The fields of the result */
  IdList *pSrc;          /* The FROM clause */
  Expr *pWhere;          /* The WHERE clause */
  ExprList *pGroupBy;    /* The GROUP BY clause */
  Expr *pHaving;         /* The HAVING clause */
  ExprList *pOrderBy;    /* The ORDER BY clause */
};

/*
** An SQL parser context
*/
struct Parse {
  sqlite *db;          /* The main database structure */
  sqlite_callback xCallback;  /* The callback function */
  void *pArg;          /* First argument to the callback function */

void sqliteDeleteTable(sqlite*, Table*);
void sqliteInsert(Parse*, Token*, ExprList*, IdList*);
IdList *sqliteIdListAppend(IdList*, Token*);
void sqliteIdListAddAlias(IdList*, Token*);
void sqliteIdListDelete(IdList*);
void sqliteCreateIndex(Parse*, Token*, Token*, IdList*, Token*, Token*);
void sqliteDropIndex(Parse*, Token*);
int sqliteSelect(Parse*, Select*, Table*, int);
Select *sqliteSelectNew(ExprList*,IdList*,Expr*,ExprList*,Expr*,ExprList*,int);
void sqliteSelectDelete(Select*);
void sqliteDeleteFrom(Parse*, Token*, Expr*);
void sqliteUpdate(Parse*, Token*, ExprList*, Expr*);
WhereInfo *sqliteWhereBegin(Parse*, IdList*, Expr*, int);
void sqliteWhereEnd(WhereInfo*);
void sqliteExprCode(Parse*, Expr*);
void sqliteExprIfTrue(Parse*, Expr*, int);
void sqliteExprIfFalse(Parse*, Expr*, int);

**
*************************************************************************
** Utility functions used throughout sqlite.
**
** This file contains functions for allocating memory, comparing
** strings, and stuff like that.
**
** $Id: util.c,v 1.11 2000/06/05 16:01:39 drh Exp $
*/
#include "sqliteInt.h"
#include <stdarg.h>
#include <ctype.h>

#ifdef MEMORY_DEBUG

    sqliteFree_(oldP,zFile,line);
    return 0;
  }
  oldPi = oldP;
  oldPi -= 2;
  if( oldPi[0]!=0xdead1122 ){
    fprintf(stderr,"Low-end memory corruption in realloc at 0x%x\n", (int)p);
    return 0;
  }
  oldN = oldPi[1];
  oldK = (oldN+sizeof(int)-1)/sizeof(int);
  if( oldPi[oldK+2]!=0xdead3344 ){
    fprintf(stderr,"High-end memory corruption in realloc at 0x%x\n", (int)p);
    return 0;
  }
  k = (n + sizeof(int) - 1)/sizeof(int);
  pi = malloc( (k+3)*sizeof(int) );
  pi[0] = 0xdead1122;
  pi[1] = n;
  pi[k+2] = 0xdead3344;
  p = &pi[2];

** inplicit conversion from one type to the other occurs as necessary.
** 
** Most of the code in this file is taken up by the sqliteVdbeExec()
** function which does the work of interpreting a VDBE program.
** But other routines are also provided to help in building up
** a program instruction by instruction.
**
** $Id: vdbe.c,v 1.15 2000/06/05 16:01:39 drh Exp $
*/
#include "sqliteInt.h"
#include <unistd.h>

/*
** SQL is translated into a sequence of instructions to be
** executed by a virtual machine.  Each instruction is an instance
** of the following structure.
*/
typedef struct VdbeOp Op;

      /* Opcode: NULL * * *
      **
      ** Push a NULL value onto the stack.
      */
      case OP_Null: {
        int i = ++p->tos;

        if( NeedStack(p, p->tos) ) goto no_mem;
        p->zStack[i] = 0;
        p->aStack[i].flags = STK_Null;
        break;
      }

      /* Opcode: Pop P1 * *