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 1.23 2004/05/25 12:05:57 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.

*/

/*
**    julianday( TIMESTRING, MOD, MOD, ...)
**
** Return the julian day number of the date specified in the arguments
*/
static void juliandayFunc(sqlite3_context *context, int argc, sqlite3_value **argv){
  DateTime x;
  if( isDate(argc, argv, &x)==0 ){
    computeJD(&x);
    sqlite3_result_double(context, x.rJD);
  }
}

/*
**    datetime( TIMESTRING, MOD, MOD, ...)
**
** Return YYYY-MM-DD HH:MM:SS
*/
static void datetimeFunc(sqlite3_context *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_result_text(context, zBuf, -1, 1);
  }
}

/*
**    time( TIMESTRING, MOD, MOD, ...)
**
** Return HH:MM:SS
*/
static void timeFunc(sqlite3_context *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_result_text(context, zBuf, -1, 1);
  }
}

/*
**    date( TIMESTRING, MOD, MOD, ...)
**
** Return YYYY-MM-DD
*/
static void dateFunc(sqlite3_context *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_result_text(context, zBuf, -1, 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(sqlite3_context *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++){

** external linkage.
*/
void sqlite3RegisterDateTimeFunctions(sqlite *db){
  static struct {
     char *zName;
     int nArg;
     int dataType;
     void (*xFunc)(sqlite3_context*,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 1.55 2004/05/25 12:05:57 danielk1977 Exp $
*/
#include <ctype.h>
#include <math.h>
#include <stdlib.h>
#include <assert.h>
#include "sqliteInt.h"
#include "vdbeInt.h"
#include "os.h"

/*
** Implementation of the non-aggregate min() and max() functions
*/
static void minmaxFunc(sqlite3_context *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;

  }
  sqlite3_result_text(context, zBest, -1, 1);
}

/*
** Return the type of the argument.
*/
static void typeofFunc(sqlite3_context *context, int argc, sqlite3_value **argv){
  const char *z = 0;
  assert( argc==2 );
  switch( sqlite3_value_type(argv[0]) ){
    case SQLITE3_NULL: z = "null" ; break;
    case SQLITE3_INTEGER: z = "integer" ; break;
    case SQLITE3_TEXT: z = "text" ; break;
    case SQLITE3_FLOAT: z = "real" ; break;
    case SQLITE3_BLOB: z = "blob" ; break;
  }
  sqlite3_result_text(context, z, -1, 0);
}

/*
** Implementation of the length() function
*/
static void lengthFunc(sqlite3_context *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_result_int32(context, len);
}

/*
** Implementation of the abs() function
*/
static void absFunc(sqlite3_context *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_result_text(context, z, -1, 1);
}

/*
** Implementation of the substr() function
*/
static void substrFunc(sqlite3_context *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 );

  if( p2<0 ) p2 = 0;
  sqlite3_result_text(context, &z[p1], p2, 1);
}

/*
** Implementation of the round() function
*/
static void roundFunc(sqlite3_context *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_result_text(context, zBuf, -1, 1);
}

/*
** Implementation of the upper() and lower() SQL functions.
*/
static void upperFunc(sqlite3_context *context, int argc, sqlite3_value **argv){
  char *z;
  int i;
  if( argc<1 || SQLITE3_NULL==sqlite3_value_type(argv[0]) ) return;
  z = sqliteMalloc(sqlite3_value_bytes(argv[0]));
  if( z==0 ) return;
  strcpy(z, sqlite3_value_data(argv[0]));
  for(i=0; z[i]; i++){
    if( islower(z[i]) ) z[i] = toupper(z[i]);
  }
  sqlite3_result_text(context, z, -1, 1);
  sqliteFree(z);
}
static void lowerFunc(sqlite3_context *context, int argc, sqlite3_value **argv){
  char *z;
  int i;
  if( argc<1 || SQLITE3_NULL==sqlite3_value_type(argv[0]) ) return;
  z = sqliteMalloc(sqlite3_value_bytes(argv[0]));
  if( z==0 ) return;
  strcpy(z, sqlite3_value_data(argv[0]));
  for(i=0; z[i]; i++){
    if( isupper(z[i]) ) z[i] = tolower(z[i]);
  }
  sqlite3_result_text(context, z, -1, 1);
  sqliteFree(z);
}

/*
** Implementation of the IFNULL(), NVL(), and COALESCE() functions.  
** All three do the same thing.  They return the first non-NULL
** argument.
*/
static void ifnullFunc(sqlite3_context *context, int argc, sqlite3_value **argv){
  int i;
  for(i=0; i<argc; i++){
    if( SQLITE3_NULL!=sqlite3_value_type(argv[i]) ){
      sqlite3_result_text(context, sqlite3_value_data(argv[i]), -1, 1);
      break;
    }
  }
}

/*
** Implementation of random().  Return a random integer.  
*/
static void randomFunc(sqlite3_context *context, int argc, sqlite3_value **argv){
  int r;
  sqlite3Randomness(sizeof(r), &r);
  sqlite3_result_int32(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(
  sqlite3_context *context, 
  int arg, 
  sqlite3_value **argv
){
  sqlite *db = sqlite3_user_data(context);
  sqlite3_result_int32(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(sqlite3_context *context, int arg, sqlite3_value **argv){
  sqlite *db = sqlite3_user_data(context);
  sqlite3_result_int32(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(
  sqlite3_context *context, 
  int arg,
  sqlite3_value **argv
){
  sqlite *db = sqlite3_user_data(context);
  sqlite3_result_int32(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(
  sqlite3_context *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_result_int32(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(sqlite3_context *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_result_int32(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(sqlite3_context *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_result_text(context, zX, -1, 1);
  }
}

/*
** Implementation of the VERSION(*) function.  The result is the version
** of the SQLite library that is running.
*/
static void versionFunc(sqlite3_context *context, int argc, sqlite3_value **argv){
  sqlite3_result_text(context, sqlite3_version, -1, 0);
}

/*
** 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(sqlite3_context *context, int argc, sqlite3_value **argv){
  const char *zArg = sqlite3_value_data(argv[0]);
  if( argc<1 ) return;
  if( zArg==0 ){
    sqlite3_result_text(context, "NULL", 4, 0);
  }else if( sqlite3IsNumber(zArg, 0, TEXT_Utf8) ){
    sqlite3_result_text(context, zArg, -1, 1);
  }else{

  }
}

#ifdef SQLITE_SOUNDEX
/*
** Compute the soundex encoding of a word.
*/
static void soundexFunc(sqlite3_context *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,

#endif

#ifdef SQLITE_TEST
/*
** This function generates a string of random characters.  Used for
** generating test data.
*/
static void randStr(sqlite3_context *context, int argc, sqlite3_value **argv){
  static const unsigned char zSrc[] = 
     "abcdefghijklmnopqrstuvwxyz"
     "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
     "0123456789"
     ".-!,:*^+=_|?/<> ";
  int iMin, iMax, n, r, i;
  unsigned char zBuf[1000];

  double sum;     /* Sum of terms */
  int cnt;        /* Number of elements summed */
};

/*
** Routines used to compute the sum or average.
*/
static void sumStep(sqlite3_context *context, int argc, sqlite3_value **argv){
  SumCtx *p;
  if( argc<1 ) return;
  p = sqlite3_get_context(context, sizeof(*p));
  if( p && SQLITE3_NULL!=sqlite3_value_type(argv[0]) ){
    p->sum += sqlite3_value_float(argv[0]);
    p->cnt++;
  }
}
static void sumFinalize(sqlite3_context *context){
  SumCtx *p;
  p = sqlite3_get_context(context, sizeof(*p));
  sqlite3_result_double(context, p ? p->sum : 0.0);
}
static void avgFinalize(sqlite3_context *context){
  SumCtx *p;
  p = sqlite3_get_context(context, sizeof(*p));
  if( p && p->cnt>0 ){
    sqlite3_result_double(context, p->sum/(double)p->cnt);
  }
}

/*
** An instance of the following structure holds the context of a
** variance or standard deviation computation.
*/
typedef struct StdDevCtx StdDevCtx;
struct StdDevCtx {
  double sum;     /* Sum of terms */
  double sum2;    /* Sum of the squares of terms */
  int cnt;        /* Number of terms counted */
};

#if 0   /* Omit because math library is required */
/*
** Routines used to compute the standard deviation as an aggregate.
*/
static void stdDevStep(sqlite3_context *context, int argc, const char **argv){
  StdDevCtx *p;
  double x;
  if( argc<1 ) return;
  p = sqlite3_aggregate_context(context, sizeof(*p));
  if( p && argv[0] ){
    x = sqlite3AtoF(argv[0], 0);
    p->sum += x;
    p->sum2 += x*x;
    p->cnt++;
  }
}
static void stdDevFinalize(sqlite3_context *context){
  double rN = sqlite3_aggregate_count(context);
  StdDevCtx *p = sqlite3_aggregate_context(context, sizeof(*p));
  if( p && p->cnt>1 ){
    double rCnt = cnt;
    sqlite3_set_result_double(context, 
       sqrt((p->sum2 - p->sum*p->sum/rCnt)/(rCnt-1.0)));
  }

struct CountCtx {
  int n;
};

/*
** Routines to implement the count() aggregate function.
*/
static void countStep(sqlite3_context *context, int argc, sqlite3_value **argv){
  CountCtx *p;
  p = sqlite3_get_context(context, sizeof(*p));
  if( (argc==0 || SQLITE3_NULL!=sqlite3_value_type(argv[0])) && p ){
    p->n++;
  }
}   
static void countFinalize(sqlite3_context *context){
  CountCtx *p;
  p = sqlite3_get_context(context, sizeof(*p));
  sqlite3_result_int32(context, p ? p->n : 0);
}

/*
** This function tracks state information for the min() and max()
** aggregate functions.
*/
typedef struct MinMaxCtx MinMaxCtx;
struct MinMaxCtx {
  char *z;         /* The best so far */
  char zBuf[28];   /* Space that can be used for storage */
};

/*
** Routines to implement min() and max() aggregate functions.
*/
static void minmaxStep(sqlite3_context *context, int argc, sqlite3_value **argv){
  int max = 0;
  int cmp = 0;
  Mem *pArg  = (Mem *)argv[0];
  Mem *pBest = (Mem *)sqlite3_get_context(context, sizeof(*pBest));

  if( SQLITE3_NULL==sqlite3_value_type(argv[0]) ) return;

  if( pBest->flags ){
    /* This step function is used for both the min() and max() aggregates,
    ** the only difference between the two being that the sense of the
    ** comparison is inverted. For the max() aggregate, the

    if( (max && cmp<0) || (!max && cmp>0) ){
      sqlite3VdbeMemCopy(pBest, pArg);
    }
  }else{
    sqlite3VdbeMemCopy(pBest, pArg);
  }
}
static void minMaxFinalize(sqlite3_context *context){
  sqlite3_value *pRes;
  pRes = (sqlite3_value *)sqlite3_get_context(context, sizeof(Mem));
  
  if( pRes->flags ){
    switch( sqlite3_value_type(pRes) ){
      case SQLITE3_INTEGER: 
        sqlite3_result_int32(context, sqlite3_value_int(pRes));
        break;
      case SQLITE3_FLOAT: 

*/
void sqlite3RegisterBuiltinFunctions(sqlite *db){
  static struct {
     char *zName;
     signed char nArg;
     signed char dataType;
     u8 argType;               /* 0: none.  1: db  2: (-1) */
     void (*xFunc)(sqlite3_context*,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 */

#endif
  };
  static struct {
    char *zName;
    signed char nArg;
    signed char dataType;
    u8 argType;
    void (*xStep)(sqlite3_context*,int,sqlite3_value**);
    void (*xFinalize)(sqlite3_context*);
  } aAggs[] = {
    { "min",    1, 0,              0, minmaxStep,   minMaxFinalize },
    { "max",    1, 0,              2, minmaxStep,   minMaxFinalize },
    { "sum",    1, SQLITE_NUMERIC, 0, sumStep,      sumFinalize    },
    { "avg",    1, SQLITE_NUMERIC, 0, sumStep,      avgFinalize    },
    { "count",  0, SQLITE_NUMERIC, 0, countStep,    countFinalize  },
    { "count",  1, SQLITE_NUMERIC, 0, countStep,    countFinalize  },

**
*************************************************************************
** 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 1.188 2004/05/25 12:05:57 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)(sqlite3_context*,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);
  if( nName>255 ) return 1;
  p = sqlite3FindFunction(db, zName, nName, nArg, 1);
  if( p==0 ) return 1;
  p->xFunc = xFunc;
  p->xStep = 0;
  p->xFinalize = 0;
  p->pUserData = pUserData;
  return 0;
}
int sqlite3_create_aggregate(
  sqlite *db,          /* Add the function to this database connection */
  const char *zName,   /* Name of the function to add */
  int nArg,            /* Number of arguments */
  void (*xStep)(sqlite3_context*,int,sqlite3_value**), /* The step function */
  void (*xFinalize)(sqlite3_context*),              /* The finalizer */
  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);

  return TCL_OK;
}

/*
** During testing, the special md5sum() aggregate function is available.
** inside SQLite.  The following routines implement that function.
*/
static void md5step(sqlite3_context *context, int argc, sqlite3_value **argv){
  MD5Context *p;
  int i;
  if( argc<1 ) return;
  p = sqlite3_get_context(context, sizeof(*p));
  if( p==0 ) return;
  if( sqlite3_aggregate_count(context)==1 ){
    MD5Init(p);
  }
  for(i=0; i<argc; i++){
    const char *zData = sqlite3_value_data(argv[i]);
    if( zData ){
      MD5Update(p, zData, strlen(zData));
    }
  }
}
static void md5finalize(sqlite3_context *context){
  MD5Context *p;
  unsigned char digest[16];
  char zBuf[33];
  p = sqlite3_get_context(context, sizeof(*p));
  MD5Final(digest,p);
  DigestToBase16(digest, zBuf);
  sqlite3_result_text(context, zBuf, -1, 1);
}
void Md5_Register(sqlite *db){
  sqlite3_create_aggregate(db, "md5sum", -1, md5step, md5finalize, 0);
}

**    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 1.76 2004/05/25 12:05:57 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_libversion(void);
const char *sqlite3_libencoding(void);

/*
** A pointer to the following structure is used to communicate with
** the implementations of user-defined functions.
*/
typedef struct sqlite3_context sqlite3_context;
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)(sqlite3_context*,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)(sqlite3_context*,int,sqlite3_value**), /* Called for each row */
  void (*xFinalize)(sqlite3_context*),       /* Called once to get final result */
  void *pUserData           /* Available via the sqlite3_user_data() call */
);

/*
** Use the following routine to define the datatype returned by a
** user-defined function.  The second argument can be one of the
** constants SQLITE_NUMERIC, SQLITE_TEXT, or SQLITE_ARGS or it

  const char *zName,        /* Name of the function */
  int datatype              /* The datatype for this function */
);
#define SQLITE_NUMERIC     (-1)
#define SQLITE_TEXT        (-2)
#define SQLITE_ARGS        (-3)













/*
** The next routine returns the number of calls to xStep for a particular
** aggregate function instance.  The current call to xStep counts so this
** routine always returns at least 1.
*/
int sqlite3_aggregate_count(sqlite3_context*);

/*
** This routine registers a callback with the SQLite library.  The
** callback is invoked (at compile-time, not at run-time) for each
** attempt to access a column of a table in the database.  The callback
** returns SQLITE_OK if access is allowed, SQLITE_DENY if the entire
** SQL statement should be aborted with an error and SQLITE_IGNORE

** SQLITE3_NULL      0.0
** 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*);

** 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_value_float(sqlite3_value*);


/*
** Aggregate functions use the following routine to allocate
** a structure for storing their state.  The first time this routine
** is called for a particular aggregate, a new structure of size nBytes
** is allocated, zeroed, and returned.  On subsequent calls (for the
** same aggregate instance) the same buffer is returned.  The implementation
** of the aggregate can use the returned buffer to accumulate data.
**
** The buffer allocated is freed automatically by SQLite.
*/
void *sqlite3_get_context(sqlite3_context*, int nBytes);

/*
** The pUserData parameter to the sqlite3_create_function() and
** sqlite3_create_aggregate() routines used to register user functions
** is available to the implementation of the function using this
** call.
*/

/*
** 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 1.251 2004/05/25 12:05:57 danielk1977 Exp $
*/
#include "config.h"
#include "sqlite.h"
#include "hash.h"
#include "parse.h"
#include <stdio.h>
#include <stdlib.h>

/*
** Each SQL function is defined by an instance of the following
** structure.  A pointer to this structure is stored in the sqlite.aFunc
** hash table.  When multiple functions have the same name, the hash table
** points to a linked list of these structures.
*/
struct FuncDef {
  void (*xFunc)(sqlite3_context*,int,sqlite3_value**);  /* Regular function */
  void (*xStep)(sqlite3_context*,int,sqlite3_value**);  /* Aggregate function step */
  void (*xFinalize)(sqlite3_context*);           /* Aggregate function finializer */
  signed char nArg;         /* Number of arguments.  -1 means unlimited */
  signed char dataType;     /* Arg that determines datatype.  -1=NUMERIC, */
                            /* -2=TEXT. -3=SQLITE_ARGS */
  u8 includeTypes;          /* Add datatypes to args of xFunc and xStep */
  void *pUserData;          /* User data parameter */
  FuncDef *pNext;           /* Next function with same name */
};

/*
** 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 1.69 2004/05/25 12:05:57 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(sqlite3_context *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);

**    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 1.51 2004/05/25 12:05:57 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(sqlite3_context *context, int argc, sqlite3_value **argv){
  int i;
  for(i=0; i<argc; i++){
    if( SQLITE3_NULL!=sqlite3_value_type(argv[i]) ){
      sqlite3_result_text(context, sqlite3_value_data(argv[i]), -1, 1);
      break;
    }
  }

** 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(
  sqlite3_context *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]),

/*
** Routines to implement the x_count() aggregate function.
*/
typedef struct CountCtx CountCtx;
struct CountCtx {
  int n;
};
static void countStep(sqlite3_context *context, int argc, sqlite3_value **argv){
  CountCtx *p;
  p = sqlite3_get_context(context, sizeof(*p));
  if( (argc==0 || SQLITE3_NULL!=sqlite3_value_type(argv[0]) ) && p ){
    p->n++;
  }
}   
static void countFinalize(sqlite3_context *context){
  CountCtx *p;
  p = sqlite3_get_context(context, sizeof(*p));
  sqlite3_result_int32(context, p ? p->n : 0);
}

/*
** Usage:  sqlite_test_create_aggregate DB
**
** Call the sqlite3_create_function API on the given database in order

  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(sqlite3_context *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_result_error(context, "first argument to test function "
         "may not be NULL", -1);
    }else if( sqlite3StrICmp(zArg0,"string")==0 ){

** even the public interface to SQLite, can use a pointer to this structure.
** But this file is the only place where the internal details of this
** structure are known.
**
** This structure is defined inside of vdbe.c because it uses substructures
** (Mem) which are only defined there.
*/
struct sqlite3_context {
  FuncDef *pFunc;   /* Pointer to function information.  MUST BE FIRST */
  Mem s;            /* The return value is stored here */
  void *pAgg;       /* Aggregate context */
  u8 isError;       /* Set to true for an error */
  u8 isStep;        /* Current in the step function */
  int cnt;          /* Number of times that the step function has been called */
};

VdbeOp *sqlite3VdbeGetOp(Vdbe *p, int addr){
  assert( p->magic==VDBE_MAGIC_INIT );
  assert( addr>=0 && addr<p->nOp );
  return &p->aOp[addr];
}

/*
** Extract the user data from a sqlite3_context structure and return a
** pointer to it.
*/
void *sqlite3_user_data(sqlite3_context *p){
  assert( p && p->pFunc );
  return p->pFunc->pUserData;
}

/*
** Allocate or return the aggregate context for a user function.  A new
** context is allocated on the first call.  Subsequent calls return the
** same context that was returned on prior calls.
**
** This routine is defined here in vdbe.c because it depends on knowing
** the internals of the sqlite3_context structure which is only defined in
** this source file.
*/
void *sqlite3_get_context(sqlite3_context *p, int nByte){
  assert( p && p->pFunc && p->pFunc->xStep );
  if( p->pAgg==0 ){
    if( nByte<=NBFS ){
      p->pAgg = (void*)p->s.z;
      memset(p->pAgg, 0, nByte);
    }else{
      p->pAgg = sqliteMalloc( nByte );
    }
  }
  return p->pAgg;
}

/*
** Return the number of times the Step function of a aggregate has been 
** called.
**
** This routine is defined here in vdbe.c because it depends on knowing
** the internals of the sqlite3_context structure which is only defined in
** this source file.
*/
int sqlite3_aggregate_count(sqlite3_context *p){
  assert( p && p->pFunc && p->pFunc->xStep );
  return p->cnt;
}

/*
** Compute a string that describes the P3 parameter for an opcode.
** Use zTemp for any required temporary buffer space.

  HashElem *p;
  for(p = sqliteHashFirst(&pAgg->hash); p; p = sqliteHashNext(p)){
    AggElem *pElem = sqliteHashData(p);
    assert( pAgg->apFunc!=0 );
    for(i=0; i<pAgg->nMem; i++){
      Mem *pMem = &pElem->aMem[i];
      if( pAgg->apFunc[i] && (pMem->flags & MEM_AggCtx)!=0 ){
        sqlite3_context ctx;
        ctx.pFunc = pAgg->apFunc[i];
        ctx.s.flags = MEM_Null;
        ctx.pAgg = pMem->z;
        ctx.cnt = pMem->i;
        ctx.isStep = 0;
        ctx.isError = 0;
        (*pAgg->apFunc[i]->xFinalize)(&ctx);