diff -r 5f8e5adbbed9 -r 29cda98b007e engine/sqlite/src/date.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/engine/sqlite/src/date.cpp	Thu Feb 25 14:29:19 2010 +0000
@@ -0,0 +1,1045 @@
+/*
+** 2003 October 31
+**
+** 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.
+**
+*************************************************************************
+** 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.cpp 1282 2008-11-13 09:31:33Z LarsPson $
+**
+** 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. 
+**
+** 1970-01-01 00:00:00 is JD 2440587.5
+** 2000-01-01 00:00:00 is JD 2451544.5
+**
+** This implemention requires years to be expressed as a 4-digit number
+** which means that only dates between 0000-01-01 and 9999-12-31 can
+** be represented, even though julian day numbers allow a much wider
+** range of dates.
+**
+** The Gregorian calendar system is used for all dates and times,
+** even those that predate the Gregorian calendar.  Historians usually
+** use the Julian calendar for dates prior to 1582-10-15 and for some
+** dates afterwards, depending on locale.  Beware of this difference.
+**
+** The conversion algorithms are implemented based on descriptions
+** in the following text:
+**
+**      Jean Meeus
+**      Astronomical Algorithms, 2nd Edition, 1998
+**      ISBM 0-943396-61-1
+**      Willmann-Bell, Inc
+**      Richmond, Virginia (USA)
+*/
+#include "sqliteInt.h"
+#include <ctype.h>
+#include <stdlib.h>
+#include <assert.h>
+#include <time.h>
+
+#ifndef SQLITE_OMIT_DATETIME_FUNCS
+
+/*
+** A structure for holding a single date and time.
+*/
+typedef struct DateTime DateTime;
+struct DateTime {
+  double rJD;      /* The julian day number */
+  int Y, M, D;     /* Year, month, and day */
+  int h, m;        /* Hour and minutes */
+  int tz;          /* Timezone offset in minutes */
+  double s;        /* Seconds */
+  char validYMD;   /* True if Y,M,D are valid */
+  char validHMS;   /* True if h,m,s are valid */
+  char validJD;    /* True if rJD is valid */
+  char validTZ;    /* True if tz is valid */
+};
+
+
+/*
+** Convert zDate into one or more integers.  Additional arguments
+** come in groups of 5 as follows:
+**
+**       N       number of digits in the integer
+**       min     minimum allowed value of the integer
+**       max     maximum allowed value of the integer
+**       nextC   first character after the integer
+**       pVal    where to write the integers value.
+**
+** Conversions continue until one with nextC==0 is encountered.
+** The function returns the number of successful conversions.
+*/
+static int getDigits(const char *zDate, ...){
+  va_list ap;
+  int val;
+  int N;
+  int min;
+  int max;
+  int nextC;
+  int *pVal;
+  int cnt = 0;
+  va_start(ap, zDate);
+  do{
+    N = va_arg(ap, int);
+    min = va_arg(ap, int);
+    max = va_arg(ap, int);
+    nextC = va_arg(ap, int);
+    pVal = va_arg(ap, int*);
+    val = 0;
+    while( N-- ){
+      if( !isdigit(*(u8*)zDate) ){
+        goto end_getDigits;
+      }
+      val = val*10 + *zDate - '0';
+      zDate++;
+    }
+    if( val<min || val>max || (nextC!=0 && nextC!=*zDate) ){
+      goto end_getDigits;
+    }
+    *pVal = val;
+    zDate++;
+    cnt++;
+  }while( nextC );
+end_getDigits:
+  va_end(ap);
+  return cnt;
+}
+
+/*
+** Read text from z[] and convert into a floating point number.  Return
+** the number of digits converted.
+*/
+#define getValue sqlite3AtoF
+
+/*
+** Parse a timezone extension on the end of a date-time.
+** The extension is of the form:
+**
+**        (+/-)HH:MM
+**
+** If the parse is successful, write the number of minutes
+** of change in *pnMin and return 0.  If a parser error occurs,
+** return 0.
+**
+** A missing specifier is not considered an error.
+*/
+static int parseTimezone(const char *zDate, DateTime *p){
+  int sgn = 0;
+  int nHr, nMn;
+  while( isspace(*(u8*)zDate) ){ zDate++; }
+  p->tz = 0;
+  if( *zDate=='-' ){
+    sgn = -1;
+  }else if( *zDate=='+' ){
+    sgn = +1;
+  }else{
+    return *zDate!=0;
+  }
+  zDate++;
+  if( getDigits(zDate, 2, 0, 14, ':', &nHr, 2, 0, 59, 0, &nMn)!=2 ){
+    return 1;
+  }
+  zDate += 5;
+  p->tz = sgn*(nMn + nHr*60);
+  while( isspace(*(u8*)zDate) ){ zDate++; }
+  return *zDate!=0;
+}
+
+/*
+** Parse times of the form HH:MM or HH:MM:SS or HH:MM:SS.FFFF.
+** The HH, MM, and SS must each be exactly 2 digits.  The
+** fractional seconds FFFF can be one or more digits.
+**
+** Return 1 if there is a parsing error and 0 on success.
+*/
+static int parseHhMmSs(const char *zDate, DateTime *p){
+  int h, m, s;
+  double ms = 0.0;
+  if( getDigits(zDate, 2, 0, 24, ':', &h, 2, 0, 59, 0, &m)!=2 ){
+    return 1;
+  }
+  zDate += 5;
+  if( *zDate==':' ){
+    zDate++;
+    if( getDigits(zDate, 2, 0, 59, 0, &s)!=1 ){
+      return 1;
+    }
+    zDate += 2;
+    if( *zDate=='.' && isdigit((u8)zDate[1]) ){
+      double rScale = 1.0;
+      zDate++;
+      while( isdigit(*(u8*)zDate) ){
+        ms = ms*10.0 + *zDate - '0';
+        rScale *= 10.0;
+        zDate++;
+      }
+      ms /= rScale;
+    }
+  }else{
+    s = 0;
+  }
+  p->validJD = 0;
+  p->validHMS = 1;
+  p->h = h;
+  p->m = m;
+  p->s = s + ms;
+  if( parseTimezone(zDate, p) ) return 1;
+  p->validTZ = p->tz!=0;
+  return 0;
+}
+
+/*
+** Convert from YYYY-MM-DD HH:MM:SS to julian day.  We always assume
+** that the YYYY-MM-DD is according to the Gregorian calendar.
+**
+** Reference:  Meeus page 61
+*/
+static void computeJD(DateTime *p){
+  int Y, M, D, A, B, X1, X2;
+
+  if( p->validJD ) return;
+  if( p->validYMD ){
+    Y = p->Y;
+    M = p->M;
+    D = p->D;
+  }else{
+    Y = 2000;  /* If no YMD specified, assume 2000-Jan-01 */
+    M = 1;
+    D = 1;
+  }
+  if( M<=2 ){
+    Y--;
+    M += 12;
+  }
+  A = Y/100;
+  B = 2 - A + (A/4);
+  X1 = 365.25*(Y+4716);
+  X2 = 30.6001*(M+1);
+  p->rJD = X1 + X2 + D + B - 1524.5;
+  p->validJD = 1;
+  if( p->validHMS ){
+    p->rJD += (p->h*3600.0 + p->m*60.0 + p->s)/86400.0;
+    if( p->validTZ ){
+      p->rJD -= p->tz*60/86400.0;
+      p->validYMD = 0;
+      p->validHMS = 0;
+      p->validTZ = 0;
+    }
+  }
+}
+
+/*
+** Parse dates of the form
+**
+**     YYYY-MM-DD HH:MM:SS.FFF
+**     YYYY-MM-DD HH:MM:SS
+**     YYYY-MM-DD HH:MM
+**     YYYY-MM-DD
+**
+** Write the result into the DateTime structure and return 0
+** on success and 1 if the input string is not a well-formed
+** date.
+*/
+static int parseYyyyMmDd(const char *zDate, DateTime *p){
+  int Y, M, D, neg;
+
+  if( zDate[0]=='-' ){
+    zDate++;
+    neg = 1;
+  }else{
+    neg = 0;
+  }
+  if( getDigits(zDate,4,0,9999,'-',&Y,2,1,12,'-',&M,2,1,31,0,&D)!=3 ){
+    return 1;
+  }
+  zDate += 10;
+  while( isspace(*(u8*)zDate) || 'T'==*(u8*)zDate ){ zDate++; }
+  if( parseHhMmSs(zDate, p)==0 ){
+    /* We got the time */
+  }else if( *zDate==0 ){
+    p->validHMS = 0;
+  }else{
+    return 1;
+  }
+  p->validJD = 0;
+  p->validYMD = 1;
+  p->Y = neg ? -Y : Y;
+  p->M = M;
+  p->D = D;
+  if( p->validTZ ){
+    computeJD(p);
+  }
+  return 0;
+}
+
+/*
+** Attempt to parse the given string into a Julian Day Number.  Return
+** the number of errors.
+**
+** The following are acceptable forms for the input string:
+**
+**      YYYY-MM-DD HH:MM:SS.FFF  +/-HH:MM
+**      DDDD.DD 
+**      now
+**
+** In the first form, the +/-HH:MM is always optional.  The fractional
+** seconds extension (the ".FFF") is optional.  The seconds portion
+** (":SS.FFF") is option.  The year and date can be omitted as long
+** as there is a time string.  The time string can be omitted as long
+** as there is a year and date.
+*/
+static int parseDateOrTime(
+  sqlite3_context *context, 
+  const char *zDate, 
+  DateTime *p
+){
+  memset(p, 0, sizeof(*p));
+  if( parseYyyyMmDd(zDate,p)==0 ){
+    return 0;
+  }else if( parseHhMmSs(zDate, p)==0 ){
+    return 0;
+  }else if( sqlite3StrICmp(zDate,"now")==0){
+    double r;
+    sqlite3OsCurrentTime((sqlite3_vfs *)sqlite3_user_data(context), &r);
+    p->rJD = r;
+    p->validJD = 1;
+    return 0;
+  }else if( sqlite3IsNumber(zDate, 0, SQLITE_UTF8) ){
+    getValue(zDate, &p->rJD);
+    p->validJD = 1;
+    return 0;
+  }
+  return 1;
+}
+
+/*
+** Compute the Year, Month, and Day from the julian day number.
+*/
+static void computeYMD(DateTime *p){
+  int Z, A, B, C, D, E, X1;
+  if( p->validYMD ) return;
+  if( !p->validJD ){
+    p->Y = 2000;
+    p->M = 1;
+    p->D = 1;
+  }else{
+    Z = p->rJD + 0.5;
+    A = (Z - 1867216.25)/36524.25;
+    A = Z + 1 + A - (A/4);
+    B = A + 1524;
+    C = (B - 122.1)/365.25;
+    D = 365.25*C;
+    E = (B-D)/30.6001;
+    X1 = 30.6001*E;
+    p->D = B - D - X1;
+    p->M = E<14 ? E-1 : E-13;
+    p->Y = p->M>2 ? C - 4716 : C - 4715;
+  }
+  p->validYMD = 1;
+}
+
+/*
+** Compute the Hour, Minute, and Seconds from the julian day number.
+*/
+static void computeHMS(DateTime *p){
+  int Z, s;
+  if( p->validHMS ) return;
+  computeJD(p);
+  Z = p->rJD + 0.5;
+  s = (p->rJD + 0.5 - Z)*86400000.0 + 0.5;
+  p->s = 0.001*s;
+  s = p->s;
+  p->s -= s;
+  p->h = s/3600;
+  s -= p->h*3600;
+  p->m = s/60;
+  p->s += s - p->m*60;
+  p->validHMS = 1;
+}
+
+/*
+** Compute both YMD and HMS
+*/
+static void computeYMD_HMS(DateTime *p){
+  computeYMD(p);
+  computeHMS(p);
+}
+
+/*
+** Clear the YMD and HMS and the TZ
+*/
+static void clearYMD_HMS_TZ(DateTime *p){
+  p->validYMD = 0;
+  p->validHMS = 0;
+  p->validTZ = 0;
+}
+
+/*
+** Compute the difference (in days) between localtime and UTC (a.k.a. GMT)
+** for the time value p where p is in UTC.
+*/
+static double localtimeOffset(DateTime *p){
+  DateTime x, y;
+  time_t t;
+  x = *p;
+  computeYMD_HMS(&x);
+  if( x.Y<1971 || x.Y>=2038 ){
+    x.Y = 2000;
+    x.M = 1;
+    x.D = 1;
+    x.h = 0;
+    x.m = 0;
+    x.s = 0.0;
+  } else {
+    int s = x.s + 0.5;
+    x.s = s;
+  }
+  x.tz = 0;
+  x.validJD = 0;
+  computeJD(&x);
+  t = (x.rJD-2440587.5)*86400.0 + 0.5;
+#ifdef HAVE_LOCALTIME_R
+  {
+    struct tm sLocal;
+    localtime_r(&t, &sLocal);
+    y.Y = sLocal.tm_year + 1900;
+    y.M = sLocal.tm_mon + 1;
+    y.D = sLocal.tm_mday;
+    y.h = sLocal.tm_hour;
+    y.m = sLocal.tm_min;
+    y.s = sLocal.tm_sec;
+  }
+#else
+  {
+    struct tm *pTm;
+    sqlite3_mutex_enter(sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_MASTER));
+    pTm = localtime(&t);
+    y.Y = pTm->tm_year + 1900;
+    y.M = pTm->tm_mon + 1;
+    y.D = pTm->tm_mday;
+    y.h = pTm->tm_hour;
+    y.m = pTm->tm_min;
+    y.s = pTm->tm_sec;
+    sqlite3_mutex_leave(sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_MASTER));
+  }
+#endif
+  y.validYMD = 1;
+  y.validHMS = 1;
+  y.validJD = 0;
+  y.validTZ = 0;
+  computeJD(&y);
+  return y.rJD - x.rJD;
+}
+
+/*
+** Process a modifier to a date-time stamp.  The modifiers are
+** as follows:
+**
+**     NNN days
+**     NNN hours
+**     NNN minutes
+**     NNN.NNNN seconds
+**     NNN months
+**     NNN years
+**     start of month
+**     start of year
+**     start of week
+**     start of day
+**     weekday N
+**     unixepoch
+**     localtime
+**     utc
+**
+** Return 0 on success and 1 if there is any kind of error.
+*/
+static int parseModifier(const char *zMod, DateTime *p){
+  int rc = 1;
+  int n;
+  double r;
+  char *z, zBuf[30];
+  z = zBuf;
+  for(n=0; n<sizeof(zBuf)-1 && zMod[n]; n++){
+    z[n] = tolower(zMod[n]);
+  }
+  z[n] = 0;
+  switch( z[0] ){
+    case 'l': {
+      /*    localtime
+      **
+      ** Assuming the current time value is UTC (a.k.a. GMT), shift it to
+      ** show local time.
+      */
+      if( strcmp(z, "localtime")==0 ){
+        computeJD(p);
+        p->rJD += localtimeOffset(p);
+        clearYMD_HMS_TZ(p);
+        rc = 0;
+      }
+      break;
+    }
+    case 'u': {
+      /*
+      **    unixepoch
+      **
+      ** Treat the current value of p->rJD as the number of
+      ** seconds since 1970.  Convert to a real julian day number.
+      */
+      if( strcmp(z, "unixepoch")==0 && p->validJD ){
+        p->rJD = p->rJD/86400.0 + 2440587.5;
+        clearYMD_HMS_TZ(p);
+        rc = 0;
+      }else if( strcmp(z, "utc")==0 ){
+        double c1;
+        computeJD(p);
+        c1 = localtimeOffset(p);
+        p->rJD -= c1;
+        clearYMD_HMS_TZ(p);
+        p->rJD += c1 - localtimeOffset(p);
+        rc = 0;
+      }
+      break;
+    }
+    case 'w': {
+      /*
+      **    weekday N
+      **
+      ** Move the date to the same time on the next occurrence of
+      ** weekday N where 0==Sunday, 1==Monday, and so forth.  If the
+      ** date is already on the appropriate weekday, this is a no-op.
+      */
+      if( strncmp(z, "weekday ", 8)==0 && getValue(&z[8],&r)>0
+                 && (n=r)==r && n>=0 && r<7 ){
+        int Z;
+        computeYMD_HMS(p);
+        p->validTZ = 0;
+        p->validJD = 0;
+        computeJD(p);
+        Z = p->rJD + 1.5;
+        Z %= 7;
+        if( Z>n ) Z -= 7;
+        p->rJD += n - Z;
+        clearYMD_HMS_TZ(p);
+        rc = 0;
+      }
+      break;
+    }
+    case 's': {
+      /*
+      **    start of TTTTT
+      **
+      ** Move the date backwards to the beginning of the current day,
+      ** or month or year.
+      */
+      if( strncmp(z, "start of ", 9)!=0 ) break;
+      z += 9;
+      computeYMD(p);
+      p->validHMS = 1;
+      p->h = p->m = 0;
+      p->s = 0.0;
+      p->validTZ = 0;
+      p->validJD = 0;
+      if( strcmp(z,"month")==0 ){
+        p->D = 1;
+        rc = 0;
+      }else if( strcmp(z,"year")==0 ){
+        computeYMD(p);
+        p->M = 1;
+        p->D = 1;
+        rc = 0;
+      }else if( strcmp(z,"day")==0 ){
+        rc = 0;
+      }
+      break;
+    }
+    case '+':
+    case '-':
+    case '0':
+    case '1':
+    case '2':
+    case '3':
+    case '4':
+    case '5':
+    case '6':
+    case '7':
+    case '8':
+    case '9': {
+      n = getValue(z, &r);
+      assert( n>=1 );
+      if( z[n]==':' ){
+        /* A modifier of the form (+|-)HH:MM:SS.FFF adds (or subtracts) the
+        ** specified number of hours, minutes, seconds, and fractional seconds
+        ** to the time.  The ".FFF" may be omitted.  The ":SS.FFF" may be
+        ** omitted.
+        */
+        const char *z2 = z;
+        DateTime tx;
+        int day;
+        if( !isdigit(*(u8*)z2) ) z2++;
+        memset(&tx, 0, sizeof(tx));
+        if( parseHhMmSs(z2, &tx) ) break;
+        computeJD(&tx);
+        tx.rJD -= 0.5;
+        day = (int)tx.rJD;
+        tx.rJD -= day;
+        if( z[0]=='-' ) tx.rJD = -tx.rJD;
+        computeJD(p);
+        clearYMD_HMS_TZ(p);
+        p->rJD += tx.rJD;
+        rc = 0;
+        break;
+      }
+      z += n;
+      while( isspace(*(u8*)z) ) z++;
+      n = strlen(z);
+      if( n>10 || n<3 ) break;
+      if( z[n-1]=='s' ){ z[n-1] = 0; n--; }
+      computeJD(p);
+      rc = 0;
+      if( n==3 && strcmp(z,"day")==0 ){
+        p->rJD += r;
+      }else if( n==4 && strcmp(z,"hour")==0 ){
+        p->rJD += r/24.0;
+      }else if( n==6 && strcmp(z,"minute")==0 ){
+        p->rJD += r/(24.0*60.0);
+      }else if( n==6 && strcmp(z,"second")==0 ){
+        p->rJD += r/(24.0*60.0*60.0);
+      }else if( n==5 && strcmp(z,"month")==0 ){
+        int x, y;
+        computeYMD_HMS(p);
+        p->M += r;
+        x = p->M>0 ? (p->M-1)/12 : (p->M-12)/12;
+        p->Y += x;
+        p->M -= x*12;
+        p->validJD = 0;
+        computeJD(p);
+        y = r;
+        if( y!=r ){
+          p->rJD += (r - y)*30.0;
+        }
+      }else if( n==4 && strcmp(z,"year")==0 ){
+        computeYMD_HMS(p);
+        p->Y += r;
+        p->validJD = 0;
+        computeJD(p);
+      }else{
+        rc = 1;
+      }
+      clearYMD_HMS_TZ(p);
+      break;
+    }
+    default: {
+      break;
+    }
+  }
+  return rc;
+}
+
+/*
+** Process time function arguments.  argv[0] is a date-time stamp.
+** argv[1] and following are modifiers.  Parse them all and write
+** the resulting time into the DateTime structure p.  Return 0
+** on success and 1 if there are any errors.
+*/
+static int isDate(
+  sqlite3_context *context, 
+  int argc, 
+  sqlite3_value **argv, 
+  DateTime *p
+){
+  int i;
+  const unsigned char *z;
+  if( argc==0 ) return 1;
+  z = sqlite3_value_text(argv[0]);
+  if( !z || parseDateOrTime(context, (char*)z, p) ){
+    return 1;
+  }
+  for(i=1; i<argc; i++){
+    if( (z = sqlite3_value_text(argv[i]))==0 || parseModifier((char*)z, p) ){
+      return 1;
+    }
+  }
+  return 0;
+}
+
+
+/*
+** The following routines implement the various date and time functions
+** of SQLite.
+*/
+
+/*
+**    julianday( TIMESTRING, MOD, MOD, ...)
+**
+** Return the julian day number of the date specified in the arguments
+*/
+static void juliandayFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  DateTime x;
+  if( isDate(context, 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(context, argc, argv, &x)==0 ){
+    char zBuf[100];
+    computeYMD_HMS(&x);
+    sqlite3_snprintf(sizeof(zBuf), 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, SQLITE_TRANSIENT);
+  }
+}
+
+/*
+**    time( TIMESTRING, MOD, MOD, ...)
+**
+** Return HH:MM:SS
+*/
+static void timeFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  DateTime x;
+  if( isDate(context, argc, argv, &x)==0 ){
+    char zBuf[100];
+    computeHMS(&x);
+    sqlite3_snprintf(sizeof(zBuf), zBuf, "%02d:%02d:%02d", x.h, x.m, (int)x.s);
+    sqlite3_result_text(context, zBuf, -1, SQLITE_TRANSIENT);
+  }
+}
+
+/*
+**    date( TIMESTRING, MOD, MOD, ...)
+**
+** Return YYYY-MM-DD
+*/
+static void dateFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  DateTime x;
+  if( isDate(context, argc, argv, &x)==0 ){
+    char zBuf[100];
+    computeYMD(&x);
+    sqlite3_snprintf(sizeof(zBuf), zBuf, "%04d-%02d-%02d", x.Y, x.M, x.D);
+    sqlite3_result_text(context, zBuf, -1, SQLITE_TRANSIENT);
+  }
+}
+
+/*
+**    strftime( FORMAT, TIMESTRING, MOD, MOD, ...)
+**
+** Return a string described by FORMAT.  Conversions as follows:
+**
+**   %d  day of month
+**   %f  ** fractional seconds  SS.SSS
+**   %H  hour 00-24
+**   %j  day of year 000-366
+**   %J  ** Julian day number
+**   %m  month 01-12
+**   %M  minute 00-59
+**   %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;
+  u64 n;
+  int i, j;
+  char *z;
+  const char *zFmt = (const char*)sqlite3_value_text(argv[0]);
+  char zBuf[100];
+  if( zFmt==0 || isDate(context, argc-1, argv+1, &x) ) return;
+  for(i=0, n=1; zFmt[i]; i++, n++){
+    if( zFmt[i]=='%' ){
+      switch( zFmt[i+1] ){
+        case 'd':
+        case 'H':
+        case 'm':
+        case 'M':
+        case 'S':
+        case 'W':
+          n++;
+          /* fall thru */
+        case 'w':
+        case '%':
+          break;
+        case 'f':
+          n += 8;
+          break;
+        case 'j':
+          n += 3;
+          break;
+        case 'Y':
+          n += 8;
+          break;
+        case 's':
+        case 'J':
+          n += 50;
+          break;
+        default:
+          return;  /* ERROR.  return a NULL */
+      }
+      i++;
+    }
+  }
+  if( n<sizeof(zBuf) ){
+    z = zBuf;
+  }else if( n>SQLITE_MAX_LENGTH ){
+    sqlite3_result_error_toobig(context);
+    return;
+  }else{
+    z = (char*)sqlite3_malloc( n );
+    if( z==0 ) return;
+  }
+  computeJD(&x);
+  computeYMD_HMS(&x);
+  for(i=j=0; zFmt[i]; i++){
+    if( zFmt[i]!='%' ){
+      z[j++] = zFmt[i];
+    }else{
+      i++;
+      switch( zFmt[i] ){
+        case 'd':  sqlite3_snprintf(3, &z[j],"%02d",x.D); j+=2; break;
+        case 'f': {
+          double s = x.s;
+          if( s>59.999 ) s = 59.999;
+          sqlite3_snprintf(7, &z[j],"%06.3f", s);
+          j += strlen(&z[j]);
+          break;
+        }
+        case 'H':  sqlite3_snprintf(3, &z[j],"%02d",x.h); j+=2; break;
+        case 'W': /* Fall thru */
+        case 'j': {
+          int nDay;             /* Number of days since 1st day of year */
+          DateTime y = x;
+          y.validJD = 0;
+          y.M = 1;
+          y.D = 1;
+          computeJD(&y);
+          nDay = x.rJD - y.rJD + 0.5;
+          if( zFmt[i]=='W' ){
+            int wd;   /* 0=Monday, 1=Tuesday, ... 6=Sunday */
+            wd = ((int)(x.rJD+0.5)) % 7;
+            sqlite3_snprintf(3, &z[j],"%02d",(nDay+7-wd)/7);
+            j += 2;
+          }else{
+            sqlite3_snprintf(4, &z[j],"%03d",nDay+1);
+            j += 3;
+          }
+          break;
+        }
+        case 'J': {
+          sqlite3_snprintf(20, &z[j],"%.16g",x.rJD);
+          j+=strlen(&z[j]);
+          break;
+        }
+        case 'm':  sqlite3_snprintf(3, &z[j],"%02d",x.M); j+=2; break;
+        case 'M':  sqlite3_snprintf(3, &z[j],"%02d",x.m); j+=2; break;
+        case 's': {
+          sqlite3_snprintf(30,&z[j],"%d",
+                           (int)((x.rJD-2440587.5)*86400.0 + 0.5));
+          j += strlen(&z[j]);
+          break;
+        }
+        case 'S':  sqlite3_snprintf(3,&z[j],"%02d",(int)x.s); j+=2; break;
+        case 'w':  z[j++] = (((int)(x.rJD+1.5)) % 7) + '0'; break;
+        case 'Y':  sqlite3_snprintf(5,&z[j],"%04d",x.Y); j+=strlen(&z[j]);break;
+        case '%':  z[j++] = '%'; break;
+      }
+    }
+  }
+  z[j] = 0;
+  sqlite3_result_text(context, z, -1, SQLITE_TRANSIENT);
+  if( z!=zBuf ){
+    sqlite3_free(z);
+  }
+}
+
+/*
+** current_time()
+**
+** This function returns the same value as time('now').
+*/
+static void ctimeFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  sqlite3_value *pVal = sqlite3ValueNew(0);
+  if( pVal ){
+    sqlite3ValueSetStr(pVal, -1, "now", SQLITE_UTF8, SQLITE_STATIC);
+    timeFunc(context, 1, &pVal);
+    sqlite3ValueFree(pVal);
+  }
+}
+
+/*
+** current_date()
+**
+** This function returns the same value as date('now').
+*/
+static void cdateFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  sqlite3_value *pVal = sqlite3ValueNew(0);
+  if( pVal ){
+    sqlite3ValueSetStr(pVal, -1, "now", SQLITE_UTF8, SQLITE_STATIC);
+    dateFunc(context, 1, &pVal);
+    sqlite3ValueFree(pVal);
+  }
+}
+
+/*
+** current_timestamp()
+**
+** This function returns the same value as datetime('now').
+*/
+static void ctimestampFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  sqlite3_value *pVal = sqlite3ValueNew(0);
+  if( pVal ){
+    sqlite3ValueSetStr(pVal, -1, "now", SQLITE_UTF8, SQLITE_STATIC);
+    datetimeFunc(context, 1, &pVal);
+    sqlite3ValueFree(pVal);
+  }
+}
+#endif /* !defined(SQLITE_OMIT_DATETIME_FUNCS) */
+
+#ifdef SQLITE_OMIT_DATETIME_FUNCS
+/*
+** If the library is compiled to omit the full-scale date and time
+** handling (to get a smaller binary), the following minimal version
+** of the functions current_time(), current_date() and current_timestamp()
+** are included instead. This is to support column declarations that
+** include "DEFAULT CURRENT_TIME" etc.
+**
+** This function uses the C-library functions time(), gmtime()
+** and strftime(). The format string to pass to strftime() is supplied
+** as the user-data for the function.
+*/
+static void currentTimeFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  time_t t;
+  char *zFormat = (char *)sqlite3_user_data(context);
+  char zBuf[20];
+
+  time(&t);
+#ifdef SQLITE_TEST
+  {
+    extern int sqlite3_current_time;  /* See os_XXX.c */
+    if( sqlite3_current_time ){
+      t = sqlite3_current_time;
+    }
+  }
+#endif
+
+#ifdef HAVE_GMTIME_R
+  {
+    struct tm sNow;
+    gmtime_r(&t, &sNow);
+    strftime(zBuf, 20, zFormat, &sNow);
+  }
+#else
+  {
+    struct tm *pTm;
+    sqlite3_mutex_enter(sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_MASTER));
+    pTm = gmtime(&t);
+    strftime(zBuf, 20, zFormat, pTm);
+    sqlite3_mutex_leave(sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_MASTER));
+  }
+#endif
+
+  sqlite3_result_text(context, zBuf, -1, SQLITE_TRANSIENT);
+}
+#endif
+
+/*
+** This function registered all of the above C functions as SQL
+** functions.  This should be the only routine in this file with
+** external linkage.
+*/
+void sqlite3RegisterDateTimeFunctions(sqlite3 *db){
+#ifndef SQLITE_OMIT_DATETIME_FUNCS
+  static const struct {
+     char *zName;
+     int nArg;
+     void (*xFunc)(sqlite3_context*,int,sqlite3_value**);
+  } aFuncs[] = {
+    { "julianday", -1, juliandayFunc   },
+    { "date",      -1, dateFunc        },
+    { "time",      -1, timeFunc        },
+    { "datetime",  -1, datetimeFunc    },
+    { "strftime",  -1, strftimeFunc    },
+    { "current_time",       0, ctimeFunc      },
+    { "current_timestamp",  0, ctimestampFunc },
+    { "current_date",       0, cdateFunc      },
+  };
+  int i;
+
+  for(i=0; i<sizeof(aFuncs)/sizeof(aFuncs[0]); i++){
+    sqlite3CreateFunc(db, aFuncs[i].zName, aFuncs[i].nArg,
+        SQLITE_UTF8, (void *)(db->pVfs), aFuncs[i].xFunc, 0, 0);
+  }
+#else
+  static const struct {
+     char *zName;
+     char *zFormat;
+  } aFuncs[] = {
+    { "current_time", "%H:%M:%S" },
+    { "current_date", "%Y-%m-%d" },
+    { "current_timestamp", "%Y-%m-%d %H:%M:%S" }
+  };
+  int i;
+
+  for(i=0; i<sizeof(aFuncs)/sizeof(aFuncs[0]); i++){
+    sqlite3CreateFunc(db, aFuncs[i].zName, 0, SQLITE_UTF8, 
+        aFuncs[i].zFormat, currentTimeFunc, 0, 0);
+  }
+#endif
+}