SQLite

** This file contains the C functions that implement date and time
** functions for SQLite.  
**
** There is only one exported symbol in this file - the function
** sqlite3RegisterDateTimeFunctions() found at the bottom of the file.
** All other code has file scope.
**
** $Id: date.c,v 1.21 2004/05/24 12:39:02 danielk1977 Exp $
**
** NOTES:
**
** SQLite processes all times and dates as Julian Day numbers.  The
** dates and times are stored as the number of days since noon
** in Greenwich on November 24, 4714 B.C. according to the Gregorian
** calendar system.

/*
** Process time function arguments.  argv[0] is a date-time stamp.
** argv[1] and following are modifiers.  Parse them all and write
** the resulting time into the DateTime structure p.  Return 0
** on success and 1 if there are any errors.
*/
static int isDate(int argc, sqlite3_value **argv, DateTime *p){
  int i;
  if( argc==0 ) return 1;
  if( SQLITE3_NULL==sqlite3_value_type(argv[0]) || 
      parseDateOrTime(sqlite3_value_data(argv[0]), p) ) return 1;
  for(i=1; i<argc; i++){
    if( SQLITE3_NULL==sqlite3_value_type(argv[i]) || 
        parseModifier(sqlite3_value_data(argv[i]), p) ) return 1;
  }
  return 0;
}


/*
** The following routines implement the various date and time functions
** of SQLite.
*/

/*
**    julianday( TIMESTRING, MOD, MOD, ...)
**
** Return the julian day number of the date specified in the arguments
*/
static void juliandayFunc(sqlite_func *context, int argc, sqlite3_value **argv){
  DateTime x;
  if( isDate(argc, argv, &x)==0 ){
    computeJD(&x);
    sqlite3_set_result_double(context, x.rJD);
  }
}

/*
**    datetime( TIMESTRING, MOD, MOD, ...)
**
** Return YYYY-MM-DD HH:MM:SS
*/
static void datetimeFunc(sqlite_func *context, int argc, sqlite3_value **argv){
  DateTime x;
  if( isDate(argc, argv, &x)==0 ){
    char zBuf[100];
    computeYMD_HMS(&x);
    sprintf(zBuf, "%04d-%02d-%02d %02d:%02d:%02d",x.Y, x.M, x.D, x.h, x.m,
           (int)(x.s));
    sqlite3_set_result_string(context, zBuf, -1);
  }
}

/*
**    time( TIMESTRING, MOD, MOD, ...)
**
** Return HH:MM:SS
*/
static void timeFunc(sqlite_func *context, int argc, sqlite3_value **argv){
  DateTime x;
  if( isDate(argc, argv, &x)==0 ){
    char zBuf[100];
    computeHMS(&x);
    sprintf(zBuf, "%02d:%02d:%02d", x.h, x.m, (int)x.s);
    sqlite3_set_result_string(context, zBuf, -1);
  }
}

/*
**    date( TIMESTRING, MOD, MOD, ...)
**
** Return YYYY-MM-DD
*/
static void dateFunc(sqlite_func *context, int argc, sqlite3_value **argv){
  DateTime x;
  if( isDate(argc, argv, &x)==0 ){
    char zBuf[100];
    computeYMD(&x);
    sprintf(zBuf, "%04d-%02d-%02d", x.Y, x.M, x.D);
    sqlite3_set_result_string(context, zBuf, -1);
  }

**   %s  seconds since 1970-01-01
**   %S  seconds 00-59
**   %w  day of week 0-6  sunday==0
**   %W  week of year 00-53
**   %Y  year 0000-9999
**   %%  %
*/
static void strftimeFunc(sqlite_func *context, int argc, sqlite3_value **argv){
  DateTime x;
  int n, i, j;
  char *z;
  const char *zFmt = sqlite3_value_data(argv[0]);
  char zBuf[100];
  if( zFmt==0 || isDate(argc-1, argv+1, &x) ) return;
  for(i=0, n=1; zFmt[i]; i++, n++){
    if( zFmt[i]=='%' ){
      switch( zFmt[i+1] ){
        case 'd':
        case 'H':
        case 'm':
        case 'M':

** external linkage.
*/
void sqlite3RegisterDateTimeFunctions(sqlite *db){
  static struct {
     char *zName;
     int nArg;
     int dataType;
     void (*xFunc)(sqlite_func*,int,sqlite3_value**);
  } aFuncs[] = {
#ifndef SQLITE_OMIT_DATETIME_FUNCS
    { "julianday", -1, SQLITE_NUMERIC, juliandayFunc   },
    { "date",      -1, SQLITE_TEXT,    dateFunc        },
    { "time",      -1, SQLITE_TEXT,    timeFunc        },
    { "datetime",  -1, SQLITE_TEXT,    datetimeFunc    },
    { "strftime",  -1, SQLITE_TEXT,    strftimeFunc    },

** 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 1.50 2004/05/24 12:39:02 danielk1977 Exp $
*/
#include <ctype.h>
#include <math.h>
#include <stdlib.h>
#include <assert.h>
#include "sqliteInt.h"
#include "os.h"

/*
** Implementation of the non-aggregate min() and max() functions
*/
static void minmaxFunc(sqlite_func *context, int argc, sqlite3_value **argv){
  const char *zBest; 
  int i;
  int (*xCompare)(const char*, const char*);
  int mask;    /* 0 for min() or 0xffffffff for max() */
  const char *zArg;

  if( argc==0 ) return;
  mask = (int)sqlite3_user_data(context);
  zBest = sqlite3_value_data(argv[0]);
  if( zBest==0 ) return;
  zArg = sqlite3_value_data(argv[1]);
  if( zArg[0]=='n' ){
    xCompare = sqlite3Compare;
  }else{
    xCompare = strcmp;
  }
  for(i=2; i<argc; i+=2){
    zArg = sqlite3_value_data(argv[i]);
    if( zArg==0 ) return;
    if( (xCompare(zArg, zBest)^mask)<0 ){
      zBest = zArg;
    }
  }
  sqlite3_set_result_string(context, zBest, -1);
}

/*
** Return the type of the argument.
*/
static void typeofFunc(sqlite_func *context, int argc, sqlite3_value **argv){
  assert( argc==2 );
  sqlite3_set_result_string(context, sqlite3_value_data(argv[1]), -1);
}

/*
** Implementation of the length() function
*/
static void lengthFunc(sqlite_func *context, int argc, sqlite3_value **argv){
  const char *z;
  int len;

  assert( argc==1 );
  z = sqlite3_value_data(argv[0]);
  if( z==0 ) return;
#ifdef SQLITE_UTF8
  for(len=0; *z; z++){ if( (0xc0&*z)!=0x80 ) len++; }
#else
  len = strlen(z);
#endif
  sqlite3_set_result_int(context, len);
}

/*
** Implementation of the abs() function
*/
static void absFunc(sqlite_func *context, int argc, sqlite3_value **argv){
  const char *z;
  assert( argc==1 );
  z = sqlite3_value_data(argv[0]);
  if( z==0 ) return;
  if( z[0]=='-' && isdigit(z[1]) ) z++;
  sqlite3_set_result_string(context, z, -1);
}

/*
** Implementation of the substr() function
*/
static void substrFunc(sqlite_func *context, int argc, sqlite3_value **argv){
  const char *z;
#ifdef SQLITE_UTF8
  const char *z2;
  int i;
#endif
  int p1, p2, len;
  assert( argc==3 );
  z = sqlite3_value_data(argv[0]);
  if( z==0 ) return;
  p1 = sqlite3_value_int(argv[1]);
  p2 = sqlite3_value_int(argv[2]);
#ifdef SQLITE_UTF8
  for(len=0, z2=z; *z2; z2++){ if( (0xc0&*z2)!=0x80 ) len++; }
#else
  len = strlen(z);
#endif
  if( p1<0 ){
    p1 += len;

  if( p2<0 ) p2 = 0;
  sqlite3_set_result_string(context, &z[p1], p2);
}

/*
** Implementation of the round() function
*/
static void roundFunc(sqlite_func *context, int argc, sqlite3_value **argv){
  int n = 0;
  double r;
  char zBuf[100];
  assert( argc==1 || argc==2 );
  if( argc==2 ){
    if( SQLITE3_NULL==sqlite3_value_type(argv[1]) ) return;
    n = sqlite3_value_int(argv[1]);
    if( n>30 ) n = 30;
    if( n<0 ) n = 0;
  }
  if( SQLITE3_NULL==sqlite3_value_type(argv[0]) ) return;
  r = sqlite3_value_float(argv[0]);
  sprintf(zBuf,"%.*f",n,r);
  sqlite3_set_result_string(context, zBuf, -1);
}

/*
** Implementation of the upper() and lower() SQL functions.
*/
static void upperFunc(sqlite_func *context, int argc, sqlite3_value **argv){
  char *z;
  int i;
  if( argc<1 ) return;
  z = sqlite3_set_result_string(context, sqlite3_value_data(argv[0]), -1);
  if( z==0 ) return;
  for(i=0; z[i]; i++){
    if( islower(z[i]) ) z[i] = toupper(z[i]);
  }
}
static void lowerFunc(sqlite_func *context, int argc, sqlite3_value **argv){
  char *z;
  int i;
  if( argc<1 ) return;
  z = sqlite3_set_result_string(context, sqlite3_value_data(argv[0]), -1);
  if( z==0 ) return;
  for(i=0; z[i]; i++){
    if( isupper(z[i]) ) z[i] = tolower(z[i]);
  }
}

/*
** Implementation of the IFNULL(), NVL(), and COALESCE() functions.  
** All three do the same thing.  They return the first non-NULL
** argument.
*/
static void ifnullFunc(sqlite_func *context, int argc, sqlite3_value **argv){
  int i;
  for(i=0; i<argc; i++){
    if( SQLITE3_NULL!=sqlite3_value_type(argv[i]) ){
      sqlite3_set_result_string(context, sqlite3_value_data(argv[i]), -1);
      break;
    }
  }
}

/*
** Implementation of random().  Return a random integer.  
*/
static void randomFunc(sqlite_func *context, int argc, sqlite3_value **argv){
  int r;
  sqlite3Randomness(sizeof(r), &r);
  sqlite3_set_result_int(context, r);
}

/*
** Implementation of the last_insert_rowid() SQL function.  The return
** value is the same as the sqlite3_last_insert_rowid() API function.
*/
static void last_insert_rowid(
  sqlite_func *context, 
  int arg, 
  sqlite3_value **argv
){
  sqlite *db = sqlite3_user_data(context);
  sqlite3_set_result_int(context, sqlite3_last_insert_rowid(db));
}

/*
** Implementation of the change_count() SQL function.  The return
** value is the same as the sqlite3_changes() API function.
*/
static void change_count(sqlite_func *context, int arg, sqlite3_value **argv){
  sqlite *db = sqlite3_user_data(context);
  sqlite3_set_result_int(context, sqlite3_changes(db));
}

/*
** Implementation of the last_statement_change_count() SQL function.  The
** return value is the same as the sqlite3_last_statement_changes() API
** function.
*/
static void last_statement_change_count(
  sqlite_func *context, 
  int arg,
  sqlite3_value **argv
){
  sqlite *db = sqlite3_user_data(context);
  sqlite3_set_result_int(context, sqlite3_last_statement_changes(db));
}

/*
** Implementation of the like() SQL function.  This function implements
** the build-in LIKE operator.  The first argument to the function is the
** string and the second argument is the pattern.  So, the SQL statements:
**
**       A LIKE B
**
** is implemented as like(A,B).
*/
static void likeFunc(
  sqlite_func *context, 
  int argc, 
  sqlite3_value **argv
){
  const unsigned char *zA = sqlite3_value_data(argv[0]);
  const unsigned char *zB = sqlite3_value_data(argv[1]);
  if( zA && zB ){
    sqlite3_set_result_int(context, sqlite3LikeCompare(zA, zB));
  }
}

/*
** 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, sqlite3_value **argv){
  const unsigned char *zA = sqlite3_value_data(argv[0]);
  const unsigned char *zB = sqlite3_value_data(argv[1]);
  if( zA && zB ){
    sqlite3_set_result_int(context, sqlite3GlobCompare(zA, zB));


  }
}

/*
** 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.
*/
static void nullifFunc(sqlite_func *context, int argc, sqlite3_value **argv){
  const unsigned char *zX = sqlite3_value_data(argv[0]);
  const unsigned char *zY = sqlite3_value_data(argv[1]);
  if( zX!=0 && sqlite3Compare(zX, zY)!=0 ){
    sqlite3_set_result_string(context, zX, -1);
  }
}

/*
** 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, sqlite3_value **argv){
  sqlite3_set_result_string(context, sqlite3_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, sqlite3_value **argv){
  const char *zArg = sqlite3_value_data(argv[0]);
  if( argc<1 ) return;
  if( zArg==0 ){
    sqlite3_set_result_string(context, "NULL", 4);
  }else if( sqlite3IsNumber(zArg, 0, TEXT_Utf8) ){
    sqlite3_set_result_string(context, zArg, -1);
  }else{
    int i,j,n;
    char *z;
    for(i=n=0; zArg[i]; i++){ if( zArg[i]=='\'' ) n++; }
    z = sqliteMalloc( i+n+3 );
    if( z==0 ) return;
    z[0] = '\'';
    for(i=0, j=1; zArg[i]; i++){
      z[j++] = zArg[i];
      if( zArg[i]=='\'' ){
        z[j++] = '\'';
      }
    }
    z[j++] = '\'';
    z[j] = 0;
    sqlite3_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, sqlite3_value **argv){
  char zResult[8];
  const char *zIn;
  int i, j;
  static const unsigned char iCode[] = {
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 1, 2, 3, 0, 1, 2, 0, 0, 2, 2, 4, 5, 5, 0,
    1, 2, 6, 2, 3, 0, 1, 0, 2, 0, 2, 0, 0, 0, 0, 0,
    0, 0, 1, 2, 3, 0, 1, 2, 0, 0, 2, 2, 4, 5, 5, 0,
    1, 2, 6, 2, 3, 0, 1, 0, 2, 0, 2, 0, 0, 0, 0, 0,
  };
  assert( argc==1 );
  zIn = sqlite3_value_data(argv[0]);
  for(i=0; zIn[i] && !isalpha(zIn[i]); i++){}
  if( zIn[i] ){
    zResult[0] = toupper(zIn[i]);
    for(j=1; j<4 && zIn[i]; i++){
      int code = iCode[zIn[i]&0x7f];
      if( code>0 ){
        zResult[j++] = code + '0';

#endif

#ifdef SQLITE_TEST
/*
** This function generates a string of random characters.  Used for
** generating test data.
*/
static void randStr(sqlite_func *context, int argc, sqlite3_value **argv){
  static const unsigned char zSrc[] = 
     "abcdefghijklmnopqrstuvwxyz"
     "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
     "0123456789"
     ".-!,:*^+=_|?/<> ";
  int iMin, iMax, n, r, i;
  unsigned char zBuf[1000];
  if( argc>=1 ){
    iMin = atoi(sqlite3_value_data(argv[0]));
    if( iMin<0 ) iMin = 0;
    if( iMin>=sizeof(zBuf) ) iMin = sizeof(zBuf)-1;
  }else{
    iMin = 1;
  }
  if( argc>=2 ){
    iMax = atoi(sqlite3_value_data(argv[1]));
    if( iMax<iMin ) iMax = iMin;
    if( iMax>=sizeof(zBuf) ) iMax = sizeof(zBuf)-1;
  }else{
    iMax = 50;
  }
  n = iMin;
  if( iMax>iMin ){

*/
void sqlite3RegisterBuiltinFunctions(sqlite *db){
  static struct {
     char *zName;
     signed char nArg;
     signed char dataType;
     u8 argType;               /* 0: none.  1: db  2: (-1) */
     void (*xFunc)(sqlite_func*,int,sqlite3_value **);
  } aFuncs[] = {
    { "min",       -1, SQLITE_ARGS,    0, minmaxFunc },
    { "min",        0, 0,              0, 0          },
    { "max",       -1, SQLITE_ARGS,    2, minmaxFunc },
    { "max",        0, 0,              2, 0          },
    { "typeof",     1, SQLITE_TEXT,    0, typeofFunc },
    { "classof",    1, SQLITE_TEXT,    0, typeofFunc }, /* FIX ME: hack */

  }
  for(i=0; i<sizeof(aAggs)/sizeof(aAggs[0]); i++){
    void *pArg = aAggs[i].argType==2 ? (void*)(-1) : db;
    sqlite3_create_aggregate(db, aAggs[i].zName,
           aAggs[i].nArg, aAggs[i].xStep, aAggs[i].xFinalize, pArg);
    sqlite3_function_type(db, aAggs[i].zName, aAggs[i].dataType);
  }

  for(i=0; i<sizeof(azTypeFuncs)/sizeof(azTypeFuncs[0]); i++){
    int n = strlen(azTypeFuncs[i]);
    FuncDef *p = sqlite3HashFind(&db->aFunc, azTypeFuncs[i], n);
    while( p ){
      p->includeTypes = 1;
      p = p->pNext;
    }
  }
  sqlite3RegisterDateTimeFunctions(db);
}

**
*************************************************************************
** 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 1.186 2004/05/24 12:39:02 danielk1977 Exp $
*/
#include "sqliteInt.h"
#include "os.h"
#include <ctype.h>

/*
** A pointer to this structure is used to communicate information

** If nArg is -1 it means that this function will accept any number
** of arguments, including 0.  The maximum allowed value of nArg is 127.
*/
int sqlite3_create_function(
  sqlite *db,          /* Add the function to this database connection */
  const char *zName,   /* Name of the function to add */
  int nArg,            /* Number of arguments */
  void (*xFunc)(sqlite_func*,int,sqlite3_value **), /* The implementation */
  void *pUserData      /* User data */
){
  FuncDef *p;
  int nName;
  if( db==0 || zName==0 || sqlite3SafetyCheck(db) ) return 1;
  if( nArg<-1 || nArg>127 ) return 1;
  nName = strlen(zName);

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This header file defines the interface that the SQLite library
** presents to client programs.
**
** @(#) $Id: sqlite.h.in,v 1.73 2004/05/24 12:39:02 danielk1977 Exp $
*/
#ifndef _SQLITE_H_
#define _SQLITE_H_
#include <stdarg.h>     /* Needed for the definition of va_list */

/*
** Make sure we can call this stuff from C++.

const char *sqlite3_libencoding(void);

/*
** A pointer to the following structure is used to communicate with
** the implementations of user-defined functions.
*/
typedef struct sqlite_func sqlite_func;
typedef struct Mem sqlite3_value;

/*
** Use the following routines to create new user-defined functions.  See
** the documentation for details.
*/
int sqlite3_create_function(
  sqlite*,                  /* Database where the new function is registered */
  const char *zName,        /* Name of the new function */
  int nArg,                 /* Number of arguments.  -1 means any number */
  void (*xFunc)(sqlite_func*,int,sqlite3_value **),  /* C code to implement */
  void *pUserData           /* Available via the sqlite3_user_data() call */
);
int sqlite3_create_aggregate(
  sqlite*,                  /* Database where the new function is registered */
  const char *zName,        /* Name of the function */
  int nArg,                 /* Number of arguments */
  void (*xStep)(sqlite_func*,int,const char**), /* Called for each row */

** SQLITE3_INTEGER   The value of the integer. Some rounding may occur.
** SQLITE3_FLOAT     The value of the float.
** SQLITE3_TEXT      Real number conversion of string, or 0.0
** SQLITE3_BLOB      0.0
*/
double sqlite3_column_float(sqlite3_stmt*,int);



/*
** Return the type of the sqlite3_value* passed as the first argument. 
** The type is one of SQLITE3_NULL, SQLITE3_INTEGER, SQLITE3_FLOAT,
** SQLITE3_TEXT or SQLITE3_BLOB.
*/
int sqlite3_value_type(sqlite3_value*);

/*
** 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.
**
*************************************************************************
** A TCL Interface to SQLite
**
** $Id: tclsqlite.c,v 1.67 2004/05/24 12:39:02 danielk1977 Exp $
*/
#ifndef NO_TCL     /* Omit this whole file if TCL is unavailable */

#include "sqliteInt.h"
#include "tcl.h"
#include <stdlib.h>
#include <string.h>

  return 0;
}

/*
** This routine is called to evaluate an SQL function implemented
** using TCL script.
*/
static void tclSqlFunc(sqlite_func *context, int argc, sqlite3_value **argv){
  SqlFunc *p = sqlite3_user_data(context);
  Tcl_DString cmd;
  int i;
  int rc;

  Tcl_DStringInit(&cmd);
  Tcl_DStringAppend(&cmd, p->zScript, -1);
  for(i=0; i<argc; i++){
    if( SQLITE3_NULL==sqlite3_value_type(argv[i]) ){
      Tcl_DStringAppendElement(&cmd, "");
    }else{
      Tcl_DStringAppendElement(&cmd, sqlite3_value_data(argv[i]));
    }
  }
  rc = Tcl_Eval(p->interp, Tcl_DStringValue(&cmd));
  if( rc ){
    sqlite3_set_result_error(context, Tcl_GetStringResult(p->interp), -1); 
  }else{
    sqlite3_set_result_string(context, Tcl_GetStringResult(p->interp), -1);
  }

**    May you share freely, never taking more than you give.
**
*************************************************************************
** Code for testing the printf() interface to SQLite.  This code
** is not included in the SQLite library.  It is used for automated
** testing of the SQLite library.
**
** $Id: test1.c,v 1.48 2004/05/24 12:39:02 danielk1977 Exp $
*/
#include "sqliteInt.h"
#include "tcl.h"
#include "os.h"
#include <stdlib.h>
#include <string.h>

  return TCL_OK;
}

/*
** Implementation of the x_coalesce() function.
** Return the first argument non-NULL argument.
*/
static void ifnullFunc(sqlite_func *context, int argc, sqlite3_value **argv){
  int i;
  for(i=0; i<argc; i++){
    if( SQLITE3_NULL!=sqlite3_value_type(argv[i]) ){
      sqlite3_set_result_string(context, sqlite3_value_data(argv[i]), -1);
      break;
    }
  }
}

/*
** A structure into which to accumulate text.

**
** 2004-Jan-07:  We have changed this to make it legal to call sqlite3_exec()
** from within a function call.  
** 
** This routine simulates the effect of having two threads attempt to
** use the same database at the same time.
*/
static void sqlite3ExecFunc(
  sqlite_func *context, 
  int argc,  
  sqlite3_value **argv
){
  struct dstr x;
  memset(&x, 0, sizeof(x));
  sqlite3_exec((sqlite*)sqlite3_user_data(context),
      sqlite3_value_data(argv[0]),
      execFuncCallback, &x, 0);
  sqlite3_set_result_string(context, x.z, x.nUsed);
  sqliteFree(x.z);
}

/*
** Usage:  sqlite_test_create_function DB

  return TCL_OK;
}

/*
** The following routine is a user-defined SQL function whose purpose
** is to test the sqlite_set_result() API.
*/
static void testFunc(sqlite_func *context, int argc, sqlite3_value **argv){
  while( argc>=2 ){
    const char *zArg0 = sqlite3_value_data(argv[0]);
    const char *zArg1 = sqlite3_value_data(argv[1]);
    if( zArg0==0 ){
      sqlite3_set_result_error(context, "first argument to test function "
         "may not be NULL", -1);
    }else if( sqlite3StrICmp(zArg0,"string")==0 ){
      sqlite3_set_result_string(context, zArg1, -1);
    }else if( zArg1==0 ){
      sqlite3_set_result_error(context, "2nd argument may not be NULL if the "
         "first argument is not \"string\"", -1);
    }else if( sqlite3StrICmp(zArg0,"int")==0 ){
      sqlite3_set_result_int(context, atoi(zArg1));
    }else if( sqlite3StrICmp(zArg0,"double")==0 ){
      sqlite3_set_result_double(context, sqlite3AtoF(zArg1, 0));
    }else{
      sqlite3_set_result_error(context,"first argument should be one of: "
          "string int double", -1);
    }
    argc -= 2;
    argv += 2;
  }

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains routines used to translate between UTF-8, 
** UTF-16, UTF-16BE, and UTF-16LE.
**
** $Id: utf.c,v 1.10 2004/05/24 12:39:02 danielk1977 Exp $
**
** Notes on UTF-8:
**
**   Byte-0    Byte-1    Byte-2    Byte-3    Value
**  0xxxxxxx                                 00000000 00000000 0xxxxxxx
**  110yyyyy  10xxxxxx                       00000000 00000yyy yyxxxxxx
**  1110zzzz  10yyyyyy  10xxxxxx             00000000 zzzzyyyy yyxxxxxx

  }else{
    *zOut = sqlite3utf16to8(zData, nData, enc1==TEXT_Utf16be);
    if( !(*zOut) ) return SQLITE_NOMEM;
    *nOut = strlen(*zOut)+1;
  }
  return SQLITE_OK;
}

**
** 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 1.326 2004/05/24 12:39:02 danielk1977 Exp $
*/
#include "sqliteInt.h"
#include "os.h"
#include <ctype.h>
#include "vdbeInt.h"

/*

** Invoke a user function (P3 is a pointer to a Function structure that
** defines the function) with P1 string arguments taken from the stack.
** Pop all arguments from the stack and push back the result.
**
** See also: AggFunc
*/
case OP_Function: {
  int i;
  Mem *pArg;

  sqlite_func ctx;
  sqlite3_value **apVal;
  int n = pOp->p1;

  n = pOp->p1;
  apVal = sqliteMalloc(sizeof(sqlite3_value*)*n);
  assert( apVal || n==0 );

  pArg = &pTos[1-n];

  for(i=0; i<n; i++, pArg++){






    SetEncodingFlags(pArg, db->enc);

    apVal[i] = pArg;
  }

  ctx.pFunc = (FuncDef*)pOp->p3;
  ctx.s.flags = MEM_Null;
  ctx.s.z = 0;
  ctx.isError = 0;
  ctx.isStep = 0;
  if( sqlite3SafetyOff(db) ) goto abort_due_to_misuse;
  (*ctx.pFunc->xFunc)(&ctx, n, apVal);
  if( sqlite3SafetyOn(db) ) goto abort_due_to_misuse;
  popStack(&pTos, n);
  pTos++;
  *pTos = ctx.s;
  if( pTos->flags & MEM_Str ){
    pTos->flags |= MEM_Term;
  }

  }

  if( pTos->flags&MEM_Str ){
    SetEncodingFlags(pTos, TEXT_Utf8);
    SetEncoding(pTos, encToFlags(db->enc)|MEM_Term);
  }

  if( apVal ) sqliteFree(apVal);
  break;
}

/* Opcode: BitAnd * * *
**
** Pop the top two elements from the stack.  Convert both elements
** to integers.  Push back onto the stack the bit-wise AND of the