** 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.
................................................................................
**
** 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);
  }
}

/*
**    strftime( FORMAT, TIMESTRING, MOD, MOD, ...)
**
** Return a string described by FORMAT.  Conversions as follows:
................................................................................
        case 'w':  z[j++] = (((int)(x.rJD+1.5)) % 7) + '0'; break;
        case 'Y':  sprintf(&z[j],"%04d",x.Y); j+=strlen(&z[j]); break;
        case '%':  z[j++] = '%'; break;
      }
    }
  }
  z[j] = 0;
  sqlite3_set_result_string(context, z, -1);
  if( z!=zBuf ){
    sqliteFree(z);
  }
}


#endif /* !defined(SQLITE_OMIT_DATETIME_FUNCS) */

** 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 1.22 2004/05/25 11:47:25 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.
................................................................................
**
** 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_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_result_text(context, zBuf, -1, 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_result_text(context, zBuf, -1, 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_result_text(context, zBuf, -1, 1);
  }
}

/*
**    strftime( FORMAT, TIMESTRING, MOD, MOD, ...)
**
** Return a string described by FORMAT.  Conversions as follows:
................................................................................
        case 'w':  z[j++] = (((int)(x.rJD+1.5)) % 7) + '0'; break;
        case 'Y':  sprintf(&z[j],"%04d",x.Y); j+=strlen(&z[j]); break;
        case '%':  z[j++] = '%'; break;
      }
    }
  }
  z[j] = 0;
  sqlite3_result_text(context, z, -1, 1);
  if( z!=zBuf ){
    sqliteFree(z);
  }
}


#endif /* !defined(SQLITE_OMIT_DATETIME_FUNCS) */

** 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 1.53 2004/05/25 01:13:21 danielk1977 Exp $
*/
#include <ctype.h>
#include <math.h>
#include <stdlib.h>
#include <assert.h>
#include "sqliteInt.h"
#include "vdbeInt.h"
................................................................................
  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){
  const char *z = 0;
................................................................................
  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_set_result_string(context, z, -1);
}

/*
** Implementation of the length() function
*/
static void lengthFunc(sqlite_func *context, int argc, sqlite3_value **argv){
  const char *z;
................................................................................
  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;
................................................................................
  while( z[i] && (z[i]&0xc0)==0x80 ){ i++; p1++; }
  for(; i<p1+p2 && z[i]; i++){
    if( (z[i]&0xc0)==0x80 ) p2++;
  }
  while( z[i] && (z[i]&0xc0)==0x80 ){ i++; p2++; }
#endif
  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;
................................................................................
    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:
**
................................................................................
  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:
................................................................................
**
** 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.
**
................................................................................
** "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] = '\'';
................................................................................
      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.
................................................................................
        zResult[j++] = code + '0';
      }
    }
    while( j<4 ){
      zResult[j++] = '0';
    }
    zResult[j] = 0;
    sqlite3_set_result_string(context, zResult, 4);
  }else{
    sqlite3_set_result_string(context, "?000", 4);
  }
}
#endif

#ifdef SQLITE_TEST
/*
** This function generates a string of random characters.  Used for
................................................................................
  }
  assert( n<sizeof(zBuf) );
  sqlite3Randomness(n, zBuf);
  for(i=0; i<n; i++){
    zBuf[i] = zSrc[zBuf[i]%(sizeof(zSrc)-1)];
  }
  zBuf[n] = 0;
  sqlite3_set_result_string(context, zBuf, n);
}
#endif

/*
** An instance of the following structure holds the context of a
** sum() or avg() aggregate computation.
*/
................................................................................
    p->sum += sqlite3_value_float(argv[0]);
    p->cnt++;
  }
}
static void sumFinalize(sqlite_func *context){
  SumCtx *p;
  p = sqlite3_aggregate_context(context, sizeof(*p));
  sqlite3_set_result_double(context, p ? p->sum : 0.0);
}
static void avgFinalize(sqlite_func *context){
  SumCtx *p;
  p = sqlite3_aggregate_context(context, sizeof(*p));
  if( p && p->cnt>0 ){
    sqlite3_set_result_double(context, p->sum/(double)p->cnt);
  }
}

/*
** An instance of the following structure holds the context of a
** variance or standard deviation computation.
*/
................................................................................
  if( (argc==0 || SQLITE3_NULL!=sqlite3_value_type(argv[0])) && p ){
    p->n++;
  }
}   
static void countFinalize(sqlite_func *context){
  CountCtx *p;
  p = sqlite3_aggregate_context(context, sizeof(*p));
  sqlite3_set_result_int(context, p ? p->n : 0);
}

/*
** This function tracks state information for the min() and max()
** aggregate functions.
*/
typedef struct MinMaxCtx MinMaxCtx;
................................................................................
  int cmp = 0;
  Mem *pArg  = (Mem *)argv[0];
  Mem *pBest = (Mem *)sqlite3_aggregate_context(context, sizeof(*pBest));

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

  if( pBest->flags ){








    max = ((sqlite3_user_data(context)==(void *)-1)?1:0);
    cmp = sqlite3MemCompare(pBest, pArg, 0);
    if( (max && cmp<0) || (!max && cmp>0) ){
      sqlite3MemCopy(pBest, pArg);
    }
  }else{
    sqlite3MemCopy(pBest, pArg);
  }
}
static void minMaxFinalize(sqlite_func *context){
  sqlite3_value *pRes;
  pRes = (sqlite3_value *)sqlite3_aggregate_context(context, sizeof(Mem));
  
  if( pRes->flags ){
    switch( sqlite3_value_type(pRes) ){
      case SQLITE3_INTEGER: 
        sqlite3_set_result_int(context, sqlite3_value_int(pRes));
        break;
      case SQLITE3_FLOAT: 
        sqlite3_set_result_double(context, sqlite3_value_float(pRes));
      case SQLITE3_TEXT: 
      case SQLITE3_BLOB: 
        sqlite3_set_result_string(context,
            sqlite3_value_data(pRes),
            sqlite3_value_bytes(pRes));
        break;
      case SQLITE3_NULL: 
      default:
        assert(0);
    }
  }
}

** 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 1.54 2004/05/25 11:47:25 danielk1977 Exp $
*/
#include <ctype.h>
#include <math.h>
#include <stdlib.h>
#include <assert.h>
#include "sqliteInt.h"
#include "vdbeInt.h"
................................................................................
  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_result_text(context, zBest, -1, 1);
}

/*
** Return the type of the argument.
*/
static void typeofFunc(sqlite_func *context, int argc, sqlite3_value **argv){
  const char *z = 0;
................................................................................
  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(sqlite_func *context, int argc, sqlite3_value **argv){
  const char *z;
................................................................................
  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(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_result_text(context, z, -1, 1);
}

/*
** Implementation of the substr() function
*/
static void substrFunc(sqlite_func *context, int argc, sqlite3_value **argv){
  const char *z;
................................................................................
  while( z[i] && (z[i]&0xc0)==0x80 ){ i++; p1++; }
  for(; i<p1+p2 && z[i]; i++){
    if( (z[i]&0xc0)==0x80 ) p2++;
  }
  while( z[i] && (z[i]&0xc0)==0x80 ){ i++; p2++; }
#endif
  if( p2<0 ) p2 = 0;
  sqlite3_result_text(context, &z[p1], p2, 1);
}

/*
** Implementation of the round() function
*/
static void roundFunc(sqlite_func *context, int argc, sqlite3_value **argv){
  int n = 0;
................................................................................
    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(sqlite_func *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(sqlite_func *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(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_result_text(context, sqlite3_value_data(argv[i]), -1, 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_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(
  sqlite_func *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(sqlite_func *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(
  sqlite_func *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:
**
................................................................................
  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_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:
................................................................................
**
** 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_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(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_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(sqlite_func *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.
**
................................................................................
** "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_result_text(context, "NULL", 4, 0);
  }else if( sqlite3IsNumber(zArg, 0, TEXT_Utf8) ){
    sqlite3_result_text(context, zArg, -1, 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] = '\'';
................................................................................
      z[j++] = zArg[i];
      if( zArg[i]=='\'' ){
        z[j++] = '\'';
      }
    }
    z[j++] = '\'';
    z[j] = 0;
    sqlite3_result_text(context, z, j, 1);
    sqliteFree(z);
  }
}

#ifdef SQLITE_SOUNDEX
/*
** Compute the soundex encoding of a word.
................................................................................
        zResult[j++] = code + '0';
      }
    }
    while( j<4 ){
      zResult[j++] = '0';
    }
    zResult[j] = 0;
    sqlite3_result_text(context, zResult, 4, 1);
  }else{
    sqlite3_result_text(context, "?000", 4, 0);
  }
}
#endif

#ifdef SQLITE_TEST
/*
** This function generates a string of random characters.  Used for
................................................................................
  }
  assert( n<sizeof(zBuf) );
  sqlite3Randomness(n, zBuf);
  for(i=0; i<n; i++){
    zBuf[i] = zSrc[zBuf[i]%(sizeof(zSrc)-1)];
  }
  zBuf[n] = 0;
  sqlite3_result_text(context, zBuf, n, 1);
}
#endif

/*
** An instance of the following structure holds the context of a
** sum() or avg() aggregate computation.
*/
................................................................................
    p->sum += sqlite3_value_float(argv[0]);
    p->cnt++;
  }
}
static void sumFinalize(sqlite_func *context){
  SumCtx *p;
  p = sqlite3_aggregate_context(context, sizeof(*p));
  sqlite3_result_double(context, p ? p->sum : 0.0);
}
static void avgFinalize(sqlite_func *context){
  SumCtx *p;
  p = sqlite3_aggregate_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.
*/
................................................................................
  if( (argc==0 || SQLITE3_NULL!=sqlite3_value_type(argv[0])) && p ){
    p->n++;
  }
}   
static void countFinalize(sqlite_func *context){
  CountCtx *p;
  p = sqlite3_aggregate_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;
................................................................................
  int cmp = 0;
  Mem *pArg  = (Mem *)argv[0];
  Mem *pBest = (Mem *)sqlite3_aggregate_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
    ** sqlite3_user_data() function returns (void *)-1. For min() it
    ** returns (void *)db, where db is the sqlite3* database pointer.
    ** Therefore the next statement sets variable 'max' to 1 for the max()
    ** aggregate, or 0 for min().
    */
    max = ((sqlite3_user_data(context)==(void *)-1)?1:0);
    cmp = sqlite3MemCompare(pBest, pArg, 0);
    if( (max && cmp<0) || (!max && cmp>0) ){
      sqlite3VdbeMemCopy(pBest, pArg);
    }
  }else{
    sqlite3VdbeMemCopy(pBest, pArg);
  }
}
static void minMaxFinalize(sqlite_func *context){
  sqlite3_value *pRes;
  pRes = (sqlite3_value *)sqlite3_aggregate_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: 
        sqlite3_result_double(context, sqlite3_value_float(pRes));
      case SQLITE3_TEXT: 
      case SQLITE3_BLOB: 
        sqlite3_result_text(context,
            sqlite3_value_data(pRes), sqlite3_value_bytes(pRes), 1);

        break;
      case SQLITE3_NULL: 
      default:
        assert(0);
    }
  }
}

static void md5finalize(sqlite_func *context){
  MD5Context *p;
  unsigned char digest[16];
  char zBuf[33];
  p = sqlite3_aggregate_context(context, sizeof(*p));
  MD5Final(digest,p);
  DigestToBase16(digest, zBuf);
  sqlite3_set_result_string(context, zBuf, strlen(zBuf));
}
void Md5_Register(sqlite *db){
  sqlite3_create_aggregate(db, "md5sum", -1, md5step, md5finalize, 0);
}

static void md5finalize(sqlite_func *context){
  MD5Context *p;
  unsigned char digest[16];
  char zBuf[33];
  p = sqlite3_aggregate_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 1.74 2004/05/24 23:48:27 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 *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 user function implementations call one of the following four routines
** in order to return their results.  The first parameter to each of these
** routines is a copy of the first argument to xFunc() or xFinialize().
** The second parameter to these routines is the result to be returned.
** A NULL can be passed as the second parameter to sqlite3_set_result_string()
** in order to return a NULL result.
**
** The 3rd argument to _string and _error is the number of characters to
** take from the string.  If this argument is negative, then all characters
** up to and including the first '\000' are used.
**
** The sqlite3_set_result_string() function allocates a buffer to hold the
** result and returns a pointer to this buffer.  The calling routine
** (that is, the implmentation of a user function) can alter the content
** of this buffer if desired.
*/
char *sqlite3_set_result_string(sqlite_func*,const char*,int);
void sqlite3_set_result_int(sqlite_func*,int);
void sqlite3_set_result_double(sqlite_func*,double);
void sqlite3_set_result_error(sqlite_func*,const char*,int);

/*
** 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.
*/
void *sqlite3_user_data(sqlite_func*);

/*
** 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.
................................................................................
** 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*);





























































































#ifdef __cplusplus
}  /* End of the 'extern "C"' block */
#endif
#endif

**    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 1.75 2004/05/25 11:47:26 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 *zName,        /* Name of the function */
  int datatype              /* The datatype for this function */
);
#define SQLITE_NUMERIC     (-1)
#define SQLITE_TEXT        (-2)
#define SQLITE_ARGS        (-3)































/*
** 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.
................................................................................
** 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*);

typedef sqlite_func sqlite3_context;

void *sqlite3_get_context(sqlite3_context*, int nbyte);

/*
** 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.
*/
void *sqlite3_user_data(sqlite3_context*);

/*
** The following three functions may be called from within a user-defined
** function callback or a user-defined aggregate finalizer callback. The
** result of the user-defined function or aggregate is set to the value of
** the second parameter. Any value previously set as the return value via
** an sqlite3_result_*() call is overwritten.
**
** The first parameter to each of these routines must be a copy of the
** sqlite3_context* pointer passed to the user-defined function or
** aggregate finalizer function.
*/
void sqlite3_result_int32(sqlite3_context*, int);
void sqlite3_result_int64(sqlite3_context*, long long int);
void sqlite3_result_double(sqlite3_context*, double);

/*
** This function may be called from within a user-defined function callback
** or a user-defined aggregate finalizer callback. The result of the
** user-defined function or aggregate is set to NULL.  Any value previously
** set as the return value via an sqlite3_result_*() call is overwritten.
**
** The parameter to this routine must be a copy of the sqlite3_context*
** pointer passed to the user-defined function or aggregate finalizer
** function.
*/
void sqlite3_result_null(sqlite3_context*);

/*
** The following two functions may be called from within a user-defined or
** a user-defined aggregate finalizer callback to return a text value. 
** The second parameter is a pointer to the string, encoded in UTF-8 
** for sqlite3_result_text() and UTF-16 (machine byte order) for
** sqlite3_result_text16(). 
**
** If the third parameter, n,  is positive, it is the number of bytes (not
** characters) in the string data. A negative n value indicates that the
** string may be read up to the nul terminator character.
**
** If the fourth parameter is non-zero, then a copy is made of the string.
** Otherwise, SQLite stores a pointer to the original string data.
**
** The first parameter to this routine must be a copy of the
** sqlite3_context* pointer passed to the user-defined function or
** aggregate finalizer function.
*/
void sqlite3_result_text(sqlite3_context*, const char*, int n, int eCopy);
void sqlite3_result_text16(sqlite3_context*, const void*, int n, int eCopy);

/*
** The following function may be called from within a user-defined or a
** user-defined aggregate finalizer callback to return a blob value.  The
** second parameter is a pointer to the blob of data. The third parameter
** is the number of bytes of data in the blob.
**
** If the fourth parameter is non-zero, then a copy is made of the blob.
** Otherwise, SQLite stores a pointer to the original blob data.
**
** The first parameter to this routine must be a copy of the
** sqlite3_context* pointer passed to the user-defined function or
** aggregate finalizer function.
*/
void sqlite3_result_blob(sqlite3_context*, const void*, int n, int eCopy);

/*
** These routines are used from within a user-defined or a user-defined
** aggregate finalizer callback to return an error. The second parameter
** is a pointer to a string describing the error, or NULL if no explanation
** is provided.
**
** The string should be encoded in UTF-8 for sqlite3_result_error() and
** UTF-16 (machine byte order) for sqlite3_result_error16().
**
** If not negative, the third parameter is the number of bytes (not
** characters) in the string passed as the second argument. If the third
** parameter is negative, then the string is read up to the first nul
** terminator character.
*/
void sqlite3_result_error(sqlite3_context*, const char*, int);
void sqlite3_result_error16(sqlite3_context*, const void*, int);

#ifdef __cplusplus
}  /* End of the 'extern "C"' block */
#endif
#endif

**    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>
................................................................................
      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);
  }
}
#ifndef SQLITE_OMIT_AUTHORIZATION
/*
** This is the authentication function.  It appends the authentication
** type code and the two arguments to zCmd[] then invokes the result
** on the interpreter.  The reply is examined to determine if the

**    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 1.68 2004/05/25 11:47:26 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>
................................................................................
      Tcl_DStringAppendElement(&cmd, "");
    }else{
      Tcl_DStringAppendElement(&cmd, sqlite3_value_data(argv[i]));
    }
  }
  rc = Tcl_Eval(p->interp, Tcl_DStringValue(&cmd));
  if( rc ){
    sqlite3_result_error(context, Tcl_GetStringResult(p->interp), -1); 
  }else{
    sqlite3_result_text(context, Tcl_GetStringResult(p->interp), -1, 1);
  }
}
#ifndef SQLITE_OMIT_AUTHORIZATION
/*
** This is the authentication function.  It appends the authentication
** type code and the two arguments to zCmd[] then invokes the result
** on the interpreter.  The reply is examined to determine if the

**    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 1.49 2004/05/24 23:48:27 danielk1977 Exp $
*/
#include "sqliteInt.h"
#include "tcl.h"
#include "os.h"
#include <stdlib.h>
#include <string.h>

................................................................................
** 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.
................................................................................
  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
**
** Call the sqlite3_create_function API on the given database in order
................................................................................
  if( (argc==0 || SQLITE3_NULL!=sqlite3_value_type(argv[0]) ) && p ){
    p->n++;
  }
}   
static void countFinalize(sqlite_func *context){
  CountCtx *p;
  p = sqlite3_aggregate_context(context, sizeof(*p));
  sqlite3_set_result_int(context, p ? p->n : 0);
}

/*
** Usage:  sqlite_test_create_aggregate DB
**
** Call the sqlite3_create_function API on the given database in order
** to create a function named "x_count".  This function does the same thing
................................................................................
** 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 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 1.50 2004/05/25 11:47:26 danielk1977 Exp $
*/
#include "sqliteInt.h"
#include "tcl.h"
#include "os.h"
#include <stdlib.h>
#include <string.h>

................................................................................
** 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_result_text(context, sqlite3_value_data(argv[i]), -1, 1);
      break;
    }
  }
}

/*
** A structure into which to accumulate text.
................................................................................
  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_result_text(context, x.z, x.nUsed, 1);
  sqliteFree(x.z);
}

/*
** Usage:  sqlite_test_create_function DB
**
** Call the sqlite3_create_function API on the given database in order
................................................................................
  if( (argc==0 || SQLITE3_NULL!=sqlite3_value_type(argv[0]) ) && p ){
    p->n++;
  }
}   
static void countFinalize(sqlite_func *context){
  CountCtx *p;
  p = sqlite3_aggregate_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
** to create a function named "x_count".  This function does the same thing
................................................................................
** 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_result_error(context, "first argument to test function "
         "may not be NULL", -1);
    }else if( sqlite3StrICmp(zArg0,"string")==0 ){
      sqlite3_result_text(context, zArg1, -1, 1);
    }else if( zArg1==0 ){
      sqlite3_result_error(context, "2nd argument may not be NULL if the "
         "first argument is not \"string\"", -1);
    }else if( sqlite3StrICmp(zArg0,"int")==0 ){
      sqlite3_result_int32(context, atoi(zArg1));
    }else if( sqlite3StrICmp(zArg0,"double")==0 ){
      sqlite3_result_double(context, sqlite3AtoF(zArg1, 0));
    }else{
      sqlite3_result_error(context,"first argument should be one of: "
          "string int double", -1);
    }
    argc -= 2;
    argv += 2;
  }
}

**
** 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 1.327 2004/05/24 23:48:27 danielk1977 Exp $
*/
#include "sqliteInt.h"
#include "os.h"
#include <ctype.h>
#include "vdbeInt.h"

/*
................................................................................
** each instruction in the VDBE.  When reaches zero, the SQLITE_Interrupt
** of the db.flags field is set in order to simulate and interrupt.
**
** This facility is used for testing purposes only.  It does not function
** in an ordinary build.
*/
int sqlite3_interrupt_count = 0;

























































































#if 0
/*
** NulTermify
** Stringify
** Integerify
** Realify









** SetEncoding
** Release



*/
struct MemRecord {
  char *zData;    /* Serialized record */
  int nField;     /* Number of fields in the header */
  int nHeader;    /* Number of bytes in the entire header */
  u64 *aType;     /* Type values for all entries in the record */
};
................................................................................
case OP_Callback: {
  int i;
  assert( p->nResColumn==pOp->p1 );

  for(i=0; i<pOp->p1; i++){
    Mem *pVal = &pTos[0-i];
    SetEncodingFlags(pVal, db->enc);

  }

  p->resOnStack = 1;
  p->nCallback++;
  p->popStack = pOp->p1;
  p->pc = pc + 1;
  p->pTos = pTos;
................................................................................
  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_Short ){
    pTos->z = pTos->zShort;
  }

  if( ctx.isError ){
    sqlite3SetString(&p->zErrMsg, 
       (pTos->flags & MEM_Str)!=0 ? pTos->z : "user function error", (char*)0);
    rc = SQLITE_ERROR;
  }

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

  break;
}

/* Opcode: BitAnd * * *

**
** 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 1.328 2004/05/25 11:47:26 danielk1977 Exp $
*/
#include "sqliteInt.h"
#include "os.h"
#include <ctype.h>
#include "vdbeInt.h"

/*
................................................................................
** each instruction in the VDBE.  When reaches zero, the SQLITE_Interrupt
** of the db.flags field is set in order to simulate and interrupt.
**
** This facility is used for testing purposes only.  It does not function
** in an ordinary build.
*/
int sqlite3_interrupt_count = 0;

/*
** This macro takes a single parameter, a pointer to a Mem structure.
** It returns the string encoding for the Mem structure, one of TEXT_Utf8
** TEXT_Utf16le or TEXT_Utf16be.
*/
#define MemEnc(p) ( \
   p->flags&MEM_Utf16le?TEXT_Utf16le: \
  (p->flags&MEM_Utf16le?TEXT_Utf16be:TEXT_Utf8) )

/*
** The following macros each take one parameter, a pointer to a Mem
** structure. The value returned is non-zero if the value stored in 
** the Mem structure is of or can be losslessly converted to the
** type implicit in the macro name.
** 
** MemIsNull     # NULL values
** MemIsInt      # Ints and reals and strings that can be converted to ints.
** MemIsReal     # Reals, ints and strings that look like numbers
** MemIsStr      # Strings, reals and ints.
** MemIsBlob     # Blobs.
**
** These macros do not alter the contents of the Mem structure.
*/
#define MemIsNull(p) ((p)->flags&Mem_Null)
#define MemIsBlob(p) ((p)->flags&Mem_Blob)
#define MemIsStr(p) ((p)->flags&(MEM_Int|MEM_Real|MEM_Str))
#define MemIsInt(p) ((p)->flags&MEM_Int || hardMemIsInt(p))
#define MemIsReal(p) ((p)->flags&(MEM_Int|MEM_Real) || hardMemIsReal(p))
static int hardMemIsInt(Mem *p){
  assert( !(p->flags&(MEM_Int|MEM_Real)) );
  if( p->flags&MEM_Str ){
    int realnum = 0;
    if( sqlite3IsNumber(p->z, &realnum, MemEnc(p)) && !realnum ){
      return 1;
    }
  }
  return 0;
}
static int hardMemIsReal(Mem *p){
  assert( !(p->flags&(MEM_Int|MEM_Real)) );
  if( p->flags&MEM_Str && sqlite3IsNumber(p->z, 0, MemEnc(p)) ){
    return 1;
  }
  return 0;
}

/*
** The following two macros each take one parameter, a pointer to a Mem
** structure. They return the value stored in the Mem structure coerced
** to a 64-bit integer or real, respectively.
**
** MemInt
** MemReal
**
** These macros do not alter the contents of the Mem structure, although
** they may cache the integer or real value cast of the value.
*/
#define MemInt(p) (((p)->flags&MEM_Int)?(p)->i:hardMemInt(p))
#define MemReal(p) (((p)->flags&MEM_Real)?(p)->i:hardMemReal(p))
static i64 hardMemInt(Mem *p){
  assert( !(p->flags&MEM_Int) );
  if( !MemIsInt(p) ) return 0;

  if( p->flags&MEM_Real ){
    p->i = p->r;
  }else{
    assert( p->flags&MEM_Str );
    sqlite3atoi64(p->z, &(p->i), MemEnc(p));
  }
  p->flags |= MEM_Int;
  return p->i;
}
static double hardMemReal(Mem *p){
  assert( !(p->flags&MEM_Real) );
  if( !MemIsReal(p) ) return 0.0;

  if( p->flags&MEM_Int ){
    p->r = p->i;
  }else{
    assert( p->flags&MEM_Str );
    /* p->r = sqlite3AtoF(p->z, 0, MemEnc(p)); */
    p->r = sqlite3AtoF(p->z, 0);
  }
  p->flags |= MEM_Real;
  return p->r;
}


#if 0
/*




** MemStr(Mem *pMem)
** MemBlob(Mem *pMem)
** MemBloblen(Mem *pMem)
**
** MemType(Mem *pMem)
**
** MemSetBlob
** MemSetStr
**
** MemSetEnc

** MemSetType
**
** MemCopy
*/
struct MemRecord {
  char *zData;    /* Serialized record */
  int nField;     /* Number of fields in the header */
  int nHeader;    /* Number of bytes in the entire header */
  u64 *aType;     /* Type values for all entries in the record */
};
................................................................................
case OP_Callback: {
  int i;
  assert( p->nResColumn==pOp->p1 );

  for(i=0; i<pOp->p1; i++){
    Mem *pVal = &pTos[0-i];
    SetEncodingFlags(pVal, db->enc);
    MemNulTerminate(pVal);
  }

  p->resOnStack = 1;
  p->nCallback++;
  p->popStack = pOp->p1;
  p->pc = pc + 1;
  p->pTos = pTos;
................................................................................
  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);

  /* Copy the result of the function to the top of the stack */
  pTos++;
  *pTos = ctx.s;



  if( pTos->flags & MEM_Short ){
    pTos->z = pTos->zShort;
  }
  /* If the function returned an error, throw an exception */
  if( ctx.isError ){
    sqlite3SetString(&p->zErrMsg, 
       (pTos->flags & MEM_Str)!=0 ? pTos->z : "user function error", (char*)0);
    rc = SQLITE_ERROR;
  }

  if( pTos->flags&MEM_Str ){

    SetEncoding(pTos, encToFlags(db->enc)|MEM_Term);
  }

  break;
}

/* Opcode: BitAnd * * *

** Number of bytes of string storage space available to each stack
** layer without having to malloc.  NBFS is short for Number of Bytes
** For Strings.
*/
#define NBFS 32

/*
** A single level of the stack or a single memory cell


** is an instance of the following structure. 





*/
struct Mem {
  i64 i;              /* Integer value */
  int n;              /* Number of characters in string value, including '\0' */
  int flags;          /* Some combination of MEM_Null, MEM_Str, MEM_Dyn, etc. */
  double r;           /* Real value */
  char *z;            /* String or BLOB value */
  char zShort[NBFS];  /* Space for short strings */
};
typedef struct Mem Mem;




























/*
** Allowed values for Mem.flags.
**
** The first 5 values determine the data type(s).  Null and Blob must
** occur alone.  But Str, Int, and Real can occur together.
**
** The next 3 utf entries determine the text representation for strings.
................................................................................
** These valus are only meaningful if the Str or Blob types are used.
*/
#define MEM_Null      0x0001   /* Value is NULL */
#define MEM_Str       0x0002   /* Value is a string */
#define MEM_Int       0x0004   /* Value is an integer */
#define MEM_Real      0x0008   /* Value is a real number */
#define MEM_Blob      0x0010   /* Value is a BLOB */
#define MEM_Struct    0x0020   /* Value is some kind of struct */

#define MEM_Term      0x0200   /* String has a nul terminator character */

#define MEM_Dyn       0x0400   /* Need to call sqliteFree() on Mem.z */
#define MEM_Static    0x0800   /* Mem.z points to a static string */
#define MEM_Ephem     0x1000   /* Mem.z points to an ephemeral string */
#define MEM_Short     0x2000   /* Mem.z points to Mem.zShort */
................................................................................
int sqlite3VdbeSerialPut(unsigned char *, Mem *);
int sqlite3VdbeSerialGet(const unsigned char *, u64, Mem *, u8 enc);

int sqlite2BtreeKeyCompare(BtCursor *, const void *, int, int, int *);
int sqlite3VdbeIdxKeyCompare(Cursor*, int , const unsigned char*, int*);
int sqlite3VdbeIdxRowid(BtCursor *, i64 *);
int sqlite3MemCompare(const Mem*, const Mem*, const CollSeq*);
int sqlite3MemCopy(Mem*, const Mem*);
int sqlite3VdbeKeyCompare(void*,int,const void*,int, const void*);
int sqlite3VdbeRowCompare(void*,int,const void*,int, const void*);
int sqlite3VdbeExec(Vdbe*);
int sqlite3VdbeList(Vdbe*);
int sqlite3VdbeSetEncoding(Mem *, u8);

** Number of bytes of string storage space available to each stack
** layer without having to malloc.  NBFS is short for Number of Bytes
** For Strings.
*/
#define NBFS 32

/*
** Internally, the vdbe manipulates nearly all SQL values as Mem
** structures. Each Mem struct may cache multiple representations (string,
** integer etc.) of the same value.  A value (and therefore Mem structure)
** has the following properties:
**
** Each value has a manifest type. The manifest type of the value stored
** in a Mem struct is returned by the MemType(Mem*) macro. The type is
** one of SQLITE3_NULL, SQLITE3_INTEGER, SQLITE3_REAL, SQLITE3_TEXT or
** SQLITE3_BLOB.
*/
struct Mem {
  i64 i;              /* Integer value */
  int n;              /* Number of characters in string value, including '\0' */
  int flags;          /* Some combination of MEM_Null, MEM_Str, MEM_Dyn, etc. */
  double r;           /* Real value */
  char *z;            /* String or BLOB value */
  char zShort[NBFS];  /* Space for short strings */
};
typedef struct Mem Mem;

/*
** The following three macros are used to set the value and manifest type
** stored by a Mem structure.
**
** MemSetNull - Set the value to NULL.
** MemSetInt  - Set the value to an integer.
** MemSetReal - Set the value to a real.
** MemSetStr - Set the value to a string.
*/
#define MemSetNull(p) sqlite3VdbeMemSetNull(p)
#define MemSetInt(p,v) sqlite3VdbeMemSetInt(p,v)
#define MemSetReal(p,v) sqlite3VdbeMemSetReal(p,v)
#define MemSetStr(p,z,n,enc,eCopy) sqlite3VdbeMemSetStr(p,z,n,enc,eCopy)

/*
** This macro is used to ensure a string stored in a Mem struct is NULL
** terminated. When used on an object that is not a string or is a nul
** terminated string this is a no-op. When used on a non-nul-terminated
** string a nul terminator character is appended.
**
** Non-zero is returned if a malloc() fails.
*/
#define MemNulTerminate(p) ( \
  ((p)->flags&MEM_Str) && \
  !((p)->flags&MEM_Term) && \
  sqlite3VdbeMemNulTerminate(p) )

/*
** Allowed values for Mem.flags.
**
** The first 5 values determine the data type(s).  Null and Blob must
** occur alone.  But Str, Int, and Real can occur together.
**
** The next 3 utf entries determine the text representation for strings.
................................................................................
** These valus are only meaningful if the Str or Blob types are used.
*/
#define MEM_Null      0x0001   /* Value is NULL */
#define MEM_Str       0x0002   /* Value is a string */
#define MEM_Int       0x0004   /* Value is an integer */
#define MEM_Real      0x0008   /* Value is a real number */
#define MEM_Blob      0x0010   /* Value is a BLOB */


#define MEM_Term      0x0200   /* String has a nul terminator character */

#define MEM_Dyn       0x0400   /* Need to call sqliteFree() on Mem.z */
#define MEM_Static    0x0800   /* Mem.z points to a static string */
#define MEM_Ephem     0x1000   /* Mem.z points to an ephemeral string */
#define MEM_Short     0x2000   /* Mem.z points to Mem.zShort */
................................................................................
int sqlite3VdbeSerialPut(unsigned char *, Mem *);
int sqlite3VdbeSerialGet(const unsigned char *, u64, Mem *, u8 enc);

int sqlite2BtreeKeyCompare(BtCursor *, const void *, int, int, int *);
int sqlite3VdbeIdxKeyCompare(Cursor*, int , const unsigned char*, int*);
int sqlite3VdbeIdxRowid(BtCursor *, i64 *);
int sqlite3MemCompare(const Mem*, const Mem*, const CollSeq*);

int sqlite3VdbeKeyCompare(void*,int,const void*,int, const void*);
int sqlite3VdbeRowCompare(void*,int,const void*,int, const void*);
int sqlite3VdbeExec(Vdbe*);
int sqlite3VdbeList(Vdbe*);
int sqlite3VdbeSetEncoding(Mem *, u8);
int sqlite3VdbeMemCopy(Mem*, const Mem*);
int sqlite3VdbeMemNulTerminate(Mem *);

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

/*
** The following group or routines are employed by installable functions
** to return their results.
**
** The sqlite3_set_result_string() routine can be used to return a string
** value or to return a NULL.  To return a NULL, pass in NULL for zResult.
** A copy is made of the string before this routine returns so it is safe
** to pass in an ephemeral string.
**
** sqlite3_set_result_error() works like sqlite3_set_result_string() except
** that it signals a fatal error.  The string argument, if any, is the
** error message.  If the argument is NULL a generic substitute error message
** is used.
**
** The sqlite3_set_result_int() and sqlite3_set_result_double() set the return
** value of the user function to an integer or a double.
**
** These routines are defined here in vdbe.c because they depend on knowing
** the internals of the sqlite_func structure which is only defined in 
** this source file.
*/
char *sqlite3_set_result_string(sqlite_func *p, const char *zResult, int n){
  assert( !p->isStep );
  if( p->s.flags & MEM_Dyn ){
    sqliteFree(p->s.z);
  }
  if( zResult==0 ){
    p->s.flags = MEM_Null;
    n = 0;
    p->s.z = 0;
    p->s.n = 0;
  }else{
    if( n<0 ) n = strlen(zResult);
    if( n<NBFS-1 ){
      memcpy(p->s.zShort, zResult, n);
      p->s.zShort[n] = 0;
      p->s.flags = MEM_Utf8 | MEM_Str | MEM_Short;
      p->s.z = p->s.zShort;
    }else{
      p->s.z = sqliteMallocRaw( n+1 );
      if( p->s.z ){
        memcpy(p->s.z, zResult, n);
        p->s.z[n] = 0;
      }
      p->s.flags = MEM_Utf8 | MEM_Str | MEM_Dyn;
    }
    p->s.n = n+1;
  }
  return p->s.z;
}
void sqlite3_set_result_int(sqlite_func *p, int iResult){
  assert( !p->isStep );
  if( p->s.flags & MEM_Dyn ){
    sqliteFree(p->s.z);
  }
  p->s.i = iResult;
  p->s.flags = MEM_Int;
}
void sqlite3_set_result_double(sqlite_func *p, double rResult){
  assert( !p->isStep );
  if( p->s.flags & MEM_Dyn ){
    sqliteFree(p->s.z);
  }
  p->s.r = rResult;
  p->s.flags = MEM_Real;
}
void sqlite3_set_result_error(sqlite_func *p, const char *zMsg, int n){
  assert( !p->isStep );
  sqlite3_set_result_string(p, zMsg, n);
  p->isError = 1;
}

/*
** Extract the user data from a sqlite_func structure and return a
** pointer to it.
*/
void *sqlite3_user_data(sqlite_func *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
................................................................................
  rc = memcmp(pMem1->z, pMem2->z, (pMem1->n>pMem2->n)?pMem2->n:pMem1->n);
  if( rc==0 ){
    rc = pMem1->n - pMem2->n;
  }
  return rc;
}

/*
** Copy the contents of memory cell pFrom into pTo.
*/
int sqlite3MemCopy(Mem *pTo, const Mem *pFrom){
  if( pTo->flags&MEM_Dyn ){
    sqliteFree(pTo->z);
  }

  memcpy(pTo, pFrom, sizeof(*pFrom));
  if( pTo->flags&MEM_Short ){
    pTo->z = pTo->zShort;
  }
  else if( pTo->flags&(MEM_Ephem|MEM_Dyn) ){
    pTo->flags = pTo->flags&(~(MEM_Static|MEM_Ephem|MEM_Short|MEM_Dyn));
    if( pTo->n>NBFS ){
      pTo->z = sqliteMalloc(pTo->n);
      if( !pTo->z ) return SQLITE_NOMEM;
      pTo->flags |= MEM_Dyn;
    }else{
      pTo->z = pTo->zShort;
      pTo->flags |= MEM_Short;
    }
    memcpy(pTo->z, pFrom->z, pTo->n);
  }
  return SQLITE_OK;
}

/*
** The following is the comparison function for (non-integer)
** keys in the btrees.  This function returns negative, zero, or
** positive if the first key is less than, equal to, or greater than
** the second.
**
** This function assumes that each key consists of one or more type/blob
................................................................................
  *res = sqlite3VdbeKeyCompare(pC->pKeyInfo, len, pCellKey, nKey, pKey);
  
  if( freeCellKey ){
    sqliteFree(pCellKey);
  }
  return SQLITE_OK;
}

*/
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 sqlite_func 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
................................................................................
  rc = memcmp(pMem1->z, pMem2->z, (pMem1->n>pMem2->n)?pMem2->n:pMem1->n);
  if( rc==0 ){
    rc = pMem1->n - pMem2->n;
  }
  return rc;
}




























/*
** The following is the comparison function for (non-integer)
** keys in the btrees.  This function returns negative, zero, or
** positive if the first key is less than, equal to, or greater than
** the second.
**
** This function assumes that each key consists of one or more type/blob
................................................................................
  *res = sqlite3VdbeKeyCompare(pC->pKeyInfo, len, pCellKey, nKey, pKey);
  
  if( freeCellKey ){
    sqliteFree(pCellKey);
  }
  return SQLITE_OK;
}

/*
** Parameter "enc" is one of TEXT_Utf8, TEXT_Utf16le or TEXT_Utf16be.
** Return the corresponding MEM_Utf* value.
*/
static int encToFlags(u8 enc){
  switch( enc ){
    case TEXT_Utf8: return MEM_Utf8;
    case TEXT_Utf16be: return MEM_Utf16be;
    case TEXT_Utf16le: return MEM_Utf16le;
  }
  assert(0);
}
static u8 flagsToEnc(int flags){
  switch( flags&(MEM_Utf8|MEM_Utf16be|MEM_Utf16le) ){
    case MEM_Utf8: return TEXT_Utf8;
    case MEM_Utf16le: return TEXT_Utf16le;
    case MEM_Utf16be: return TEXT_Utf16be;
  }
  return 0;
}

/*
** Delete any previous value and set the value stored in *pMem to NULL.
*/
void sqlite3VdbeMemSetNull(Mem *pMem){
  if( pMem->flags&MEM_Dyn ){
    sqliteFree(pMem->z);
  }
  pMem->flags = MEM_Null;
}

/*
** Delete any previous value and set the value stored in *pMem to val,
** manifest type INTEGER.
*/
void sqlite3VdbeMemSetInt(Mem *pMem, i64 val){
  MemSetNull(pMem);
  pMem->i = val;
  pMem->flags = MEM_Int;
}

/*
** Delete any previous value and set the value stored in *pMem to val,
** manifest type REAL.
*/
void sqlite3VdbeMemSetReal(Mem *pMem, double val){
  MemSetNull(pMem);
  pMem->r = val;
  pMem->flags = MEM_Real;
}

/*
** Copy the contents of memory cell pFrom into pTo.
*/
int sqlite3VdbeMemCopy(Mem *pTo, const Mem *pFrom){
  if( pTo->flags&MEM_Dyn ){
    sqliteFree(pTo->z);
  }

  memcpy(pTo, pFrom, sizeof(*pFrom));
  if( pTo->flags&MEM_Short ){
    pTo->z = pTo->zShort;
  }
  else if( pTo->flags&(MEM_Ephem|MEM_Dyn) ){
    pTo->flags = pTo->flags&(~(MEM_Static|MEM_Ephem|MEM_Short|MEM_Dyn));
    if( pTo->n>NBFS ){
      pTo->z = sqliteMalloc(pTo->n);
      if( !pTo->z ) return SQLITE_NOMEM;
      pTo->flags |= MEM_Dyn;
    }else{
      pTo->z = pTo->zShort;
      pTo->flags |= MEM_Short;
    }
    memcpy(pTo->z, pFrom->z, pTo->n);
  }
  return SQLITE_OK;
}

int sqlite3VdbeMemSetStr(
  Mem *pMem,          /* Memory cell to set to string value */
  const char *z,      /* String pointer */
  int n,              /* Bytes in string, or negative */
  u8 enc,             /* Encoding of z */
  int eCopy           /* True if this function should make a copy of z */
){
  Mem tmp;

  if( !z ){
    /* If z is NULL, just set *pMem to contain NULL. */
    MemSetNull(pMem);
    return SQLITE_OK;
  }

  tmp.z = (char *)z;
  if( eCopy ){
    tmp.flags = MEM_Ephem|MEM_Str;
  }else{
    tmp.flags = MEM_Static|MEM_Str;
  }
  tmp.flags |= encToFlags(enc);
  tmp.n = n;
  switch( enc ){
    case 0:
      tmp.flags |= MEM_Blob;
      break;

    case TEXT_Utf8:
      tmp.flags |= MEM_Utf8;
      if( n<0 ) tmp.n = strlen(z)+1;
      tmp.flags |= ((tmp.z[tmp.n-1])?0:MEM_Term);
      break;

    case TEXT_Utf16le:
    case TEXT_Utf16be:
      tmp.flags |= (enc==TEXT_Utf16le?MEM_Utf16le:MEM_Utf16be);
      if( n<0 ) tmp.n = sqlite3utf16ByteLen(z,-1)+1;
      tmp.flags |= ((tmp.z[tmp.n-1]||tmp.z[tmp.n-2])?0:MEM_Term);
      break;

    default:
      assert(0);
  }
  return sqlite3VdbeMemCopy(pMem, &tmp);
}

int sqlite3VdbeMemNulTerminate(Mem *pMem){
  int nulTermLen;
  int f = pMem->flags;

  assert( pMem->flags&MEM_Str && !pMem->flags&MEM_Term );
  assert( flagsToEnc(pMem->flags) );

  nulTermLen = (flagsToEnc(f)==TEXT_Utf8?1:2);

  if( pMem->n+nulTermLen<=NBFS ){
    /* If the string plus the nul terminator will fit in the Mem.zShort
    ** buffer, and it is not already stored there, copy it there.
    */
    if( !(f&MEM_Short) ){
      memcpy(pMem->z, pMem->zShort, pMem->n);
      if( f&MEM_Dyn ){
        sqliteFree(pMem->z);
      }
      pMem->z = pMem->zShort;
      pMem->flags &= ~(MEM_Static|MEM_Ephem|MEM_Dyn);
      pMem->flags |= MEM_Short;
    }
  }else{
    /* Otherwise we have to malloc for memory. If the string is already
    ** dynamic, use sqliteRealloc(). Otherwise sqliteMalloc() enough
    ** space for the string and the nul terminator, and copy the string
    ** data there.
    */
    if( f&MEM_Dyn ){
      pMem->z = (char *)sqliteRealloc(pMem->z, pMem->n+nulTermLen);
      if( !pMem->z ){
        return SQLITE_NOMEM;
      }
    }else{
      char *z = (char *)sqliteMalloc(pMem->n+nulTermLen);
      memcpy(z, pMem->z, pMem->n);
      pMem->z = z;
      pMem->flags &= ~(MEM_Static|MEM_Ephem|MEM_Short);
      pMem->flags |= MEM_Dyn;
    }
  }

  /* pMem->z now points at the string data, with enough space at the end
  ** to insert the nul nul terminator. pMem->n has not yet been updated.
  */
  memcpy(&pMem->z[pMem->n], "\0\0", nulTermLen);
  pMem->n += nulTermLen;
  pMem->flags |= MEM_Term;
}

/*
** The following nine routines, named sqlite3_result_*(), are used to
** return values or errors from user-defined functions and aggregate
** operations. They are commented in the header file sqlite.h (sqlite.h.in)
*/
void sqlite3_result_int32(sqlite3_context *pCtx, int iVal){
  MemSetInt(&pCtx->s, iVal);
}
void sqlite3_result_int64(sqlite3_context *pCtx, i64 iVal){
  MemSetInt(&pCtx->s, iVal);
}
void sqlite3_result_double(sqlite3_context *pCtx, double rVal){
  MemSetReal(&pCtx->s, rVal);
}
void sqlite3_result_null(sqlite3_context *pCtx){
  MemSetNull(&pCtx->s);
}
void sqlite3_result_text(
  sqlite3_context *pCtx, 
  const char *z, 
  int n,
  int eCopy
){
  MemSetStr(&pCtx->s, z, n, TEXT_Utf8, eCopy);
}
void sqlite3_result_text16(
  sqlite3_context *pCtx, 
  const void *z, 
  int n, 
  int eCopy
){
  MemSetStr(&pCtx->s, z, n, TEXT_Utf16, eCopy);
}
void sqlite3_result_blob(
  sqlite3_context *pCtx, 
  const void *z, 
  int n, 
  int eCopy
){
  assert( n>0 );
  MemSetStr(&pCtx->s, z, n, 0, eCopy);
}
void sqlite3_result_error(sqlite3_context *pCtx, const char *z, int n){
  pCtx->isError = 1;
  MemSetStr(&pCtx->s, z, n, TEXT_Utf8, 1);
}
void sqlite3_result_error16(sqlite3_context *pCtx, const void *z, int n){
  pCtx->isError = 1;
  MemSetStr(&pCtx->s, z, n, TEXT_Utf16, 1);
}