SQLite

** This file contains the C functions that implement various SQL
** functions of SQLite.  
**
** There is only one exported symbol in this file - the function
** sqliteRegisterBuildinFunctions() found at the bottom of the file.
** All other code has file scope.
**
** $Id: func.c,v 1.30 2003/08/26 11:41:27 drh Exp $
*/
#include <ctype.h>
#include <math.h>
#include <stdlib.h>
#include <assert.h>
#include "sqliteInt.h"
#include "os.h"

**
**       A LIKE B
**
** is implemented as like(A,B).
*/
static void likeFunc(sqlite_func *context, int arg, const char **argv){
  if( argv[0]==0 || argv[1]==0 ) return;
  sqlite_set_result_int(context, 
    sqliteLikeCompare((const unsigned char*)argv[0],
                      (const unsigned char*)argv[1]));
}

/*
** Implementation of the glob() SQL function.  This function implements
** the build-in GLOB operator.  The first argument to the function is the
** string and the second argument is the pattern.  So, the SQL statements:
**
**       A GLOB B
**
** is implemented as glob(A,B).
*/
static void globFunc(sqlite_func *context, int arg, const char **argv){
  if( argv[0]==0 || argv[1]==0 ) return;
  sqlite_set_result_int(context,
    sqliteGlobCompare((const unsigned char*)argv[0],
                      (const unsigned char*)argv[1]));
}

/*
** Implementation of the NULLIF(x,y) function.  The result is the first
** argument if the arguments are different.  The result is NULL if the
** arguments are equal to each other.
*/

** The pager is used to access a database disk file.  It implements
** atomic commit and rollback through the use of a journal file that
** is separate from the database file.  The pager also implements file
** locking to prevent two processes from writing the same database
** file simultaneously, or one process from reading the database while
** another is writing.
**
** @(#) $Id: pager.c,v 1.89 2003/08/26 11:41:27 drh Exp $
*/
#include "os.h"         /* Must be first to enable large file support */
#include "sqliteInt.h"
#include "pager.h"
#include <assert.h>
#include <string.h>

/*
** Write a 32-bit integer into a page header right before the
** page data.  This will overwrite the PgHdr.pDirty pointer.
*/
static void store32bits(u32 val, PgHdr *p, int offset){
  unsigned char *ac;
  ac = &((unsigned char*)PGHDR_TO_DATA(p))[offset];
  if( journal_format<=1 ){
    memcpy(ac, &val, 4);
  }else{
    ac[0] = (val>>24) & 0xff;
    ac[1] = (val>>16) & 0xff;
    ac[2] = (val>>8) & 0xff;
    ac[3] = val & 0xff;