** 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 1.28 2003/08/10 01:50:55 drh Exp $
*/
#include <ctype.h>
#include <math.h>
#include <stdlib.h>
#include <assert.h>
#include "sqliteInt.h"
#include "os.h"
................................................................................
/*
** Implementation of the VERSION(*) function.  The result is the version
** of the SQLite library that is running.
*/
static void versionFunc(sqlite_func *context, int argc, const char **argv){
  sqlite_set_result_string(context, sqlite_version, -1);
}






































#ifdef SQLITE_SOUNDEX
/*
** Compute the soundex encoding of a word.
*/
static void soundexFunc(sqlite_func *context, int argc, const char **argv){
  char zResult[8];
................................................................................
    { "coalesce",   1, 0,              0          },
    { "ifnull",     2, SQLITE_ARGS,    ifnullFunc },
    { "random",    -1, SQLITE_NUMERIC, randomFunc },
    { "like",       2, SQLITE_NUMERIC, likeFunc   },
    { "glob",       2, SQLITE_NUMERIC, globFunc   },
    { "nullif",     2, SQLITE_ARGS,    nullifFunc },
    { "sqlite_version",0,SQLITE_TEXT,  versionFunc},

#ifndef SQLITE_OMIT_DATETIME_FUNCS
    { "julianday", -1, SQLITE_NUMERIC, juliandayFunc   },
    { "timestamp", -1, SQLITE_TEXT,    timestampFunc   },
    { "time",      -1, SQLITE_TEXT,    timeFunc        },
    { "date",      -1, SQLITE_TEXT,    dateFunc        },
    { "year",      -1, SQLITE_NUMERIC, yearFunc        },
    { "month",     -1, SQLITE_NUMERIC, monthFunc       },

** 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 1.29 2003/08/20 01:03:34 drh Exp $
*/
#include <ctype.h>
#include <math.h>
#include <stdlib.h>
#include <assert.h>
#include "sqliteInt.h"
#include "os.h"
................................................................................
/*
** Implementation of the VERSION(*) function.  The result is the version
** of the SQLite library that is running.
*/
static void versionFunc(sqlite_func *context, int argc, const char **argv){
  sqlite_set_result_string(context, sqlite_version, -1);
}

/*
** EXPERIMENTAL - This is not an official function.  The interface may
** change.  This function may disappear.  Do not write code that depends
** on this function.
**
** Implementation of the QUOTE() function.  This function takes a single
** argument.  If the argument is numeric, the return value is the same as
** the argument.  If the argument is NULL, the return value is the string
** "NULL".  Otherwise, the argument is enclosed in single quotes with
** single-quote escapes.
*/
static void quoteFunc(sqlite_func *context, int argc, const char **argv){
  if( argc<1 ) return;
  if( argv[0]==0 ){
    sqlite_set_result_string(context, "NULL", 4);
  }else if( sqliteIsNumber(argv[0]) ){
    sqlite_set_result_string(context, argv[0], -1);
  }else{
    int i,j,n;
    char *z;
    for(i=n=0; argv[0][i]; i++){ if( argv[0][i]=='\'' ) n++; }
    z = sqliteMalloc( i+n+3 );
    if( z==0 ) return;
    z[0] = '\'';
    for(i=0, j=1; argv[0][i]; i++){
      z[j++] = argv[0][i];
      if( argv[0][i]=='\'' ){
        z[j++] = '\'';
      }
    }
    z[j++] = '\'';
    z[j] = 0;
    sqlite_set_result_string(context, z, j);
    sqliteFree(z);
  }
}

#ifdef SQLITE_SOUNDEX
/*
** Compute the soundex encoding of a word.
*/
static void soundexFunc(sqlite_func *context, int argc, const char **argv){
  char zResult[8];
................................................................................
    { "coalesce",   1, 0,              0          },
    { "ifnull",     2, SQLITE_ARGS,    ifnullFunc },
    { "random",    -1, SQLITE_NUMERIC, randomFunc },
    { "like",       2, SQLITE_NUMERIC, likeFunc   },
    { "glob",       2, SQLITE_NUMERIC, globFunc   },
    { "nullif",     2, SQLITE_ARGS,    nullifFunc },
    { "sqlite_version",0,SQLITE_TEXT,  versionFunc},
    { "quote",      1, SQLITE_ARGS,    quoteFunc  },
#ifndef SQLITE_OMIT_DATETIME_FUNCS
    { "julianday", -1, SQLITE_NUMERIC, juliandayFunc   },
    { "timestamp", -1, SQLITE_TEXT,    timestampFunc   },
    { "time",      -1, SQLITE_TEXT,    timeFunc        },
    { "date",      -1, SQLITE_TEXT,    dateFunc        },
    { "year",      -1, SQLITE_NUMERIC, yearFunc        },
    { "month",     -1, SQLITE_NUMERIC, monthFunc       },