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/*
** 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.
**
** 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 implementation 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
** ISBN 0-943396-61-1
** Willmann-Bell, Inc
** Richmond, Virginia (USA)
*/
#include "sqliteInt.h"
#include <stdlib.h>
#include <assert.h>
#include <time.h>
#ifndef SQLITE_OMIT_DATETIME_FUNCS
/*
** The MSVC CRT on Windows CE may not have a localtime() function.
** So declare a substitute. The substitute function itself is
** defined in "os_win.c".
*/
#if !defined(SQLITE_OMIT_LOCALTIME) && defined(_WIN32_WCE) && \
(!defined(SQLITE_MSVC_LOCALTIME_API) || !SQLITE_MSVC_LOCALTIME_API)
struct tm *__cdecl localtime(const time_t *);
#endif
/*
** A structure for holding a single date and time.
*/
typedef struct DateTime DateTime;
struct DateTime {
sqlite3_int64 iJD; /* The julian day number times 86400000 */
int Y, M, D; /* Year, month, and day */
int h, m; /* Hour and minutes */
int tz; /* Timezone offset in minutes */
double s; /* Seconds */
char validJD; /* True (1) if iJD is valid */
char validYMD; /* True (1) if Y,M,D are valid */
char validHMS; /* True (1) if h,m,s are valid */
char nFloor; /* Days to implement "floor" */
unsigned rawS : 1; /* Raw numeric value stored in s */
unsigned isError : 1; /* An overflow has occurred */
unsigned useSubsec : 1; /* Display subsecond precision */
unsigned isUtc : 1; /* Time is known to be UTC */
unsigned isLocal : 1; /* Time is known to be localtime */
};
/*
** Convert zDate into one or more integers according to the conversion
** specifier zFormat.
**
** zFormat[] contains 4 characters for each integer converted, except for
** the last integer which is specified by three characters. The meaning
** of a four-character format specifiers ABCD is:
**
** A: number of digits to convert. Always "2" or "4".
** B: minimum value. Always "0" or "1".
** C: maximum value, decoded as:
** a: 12
** b: 14
** c: 24
** d: 31
** e: 59
** f: 9999
** D: the separator character, or \000 to indicate this is the
** last number to convert.
**
** Example: To translate an ISO-8601 date YYYY-MM-DD, the format would
** be "40f-21a-20c". The "40f-" indicates the 4-digit year followed by "-".
** The "21a-" indicates the 2-digit month followed by "-". The "20c" indicates
** the 2-digit day which is the last integer in the set.
**
** The function returns the number of successful conversions.
*/
static int getDigits(const char *zDate, const char *zFormat, ...){
/* The aMx[] array translates the 3rd character of each format
** spec into a max size: a b c d e f */
static const u16 aMx[] = { 12, 14, 24, 31, 59, 14712 };
va_list ap;
int cnt = 0;
char nextC;
va_start(ap, zFormat);
do{
char N = zFormat[0] - '0';
char min = zFormat[1] - '0';
int val = 0;
u16 max;
assert( zFormat[2]>='a' && zFormat[2]<='f' );
max = aMx[zFormat[2] - 'a'];
nextC = zFormat[3];
val = 0;
while( N-- ){
if( !sqlite3Isdigit(*zDate) ){
goto end_getDigits;
}
val = val*10 + *zDate - '0';
zDate++;
}
if( val<(int)min || val>(int)max || (nextC!=0 && nextC!=*zDate) ){
goto end_getDigits;
}
*va_arg(ap,int*) = val;
zDate++;
cnt++;
zFormat += 4;
}while( nextC );
end_getDigits:
va_end(ap);
return cnt;
}
/*
** Parse a timezone extension on the end of a date-time.
** The extension is of the form:
**
** (+/-)HH:MM
**
** Or the "zulu" notation:
**
** Z
**
** If the parse is successful, write the number of minutes
** of change in p->tz and return 0. If a parser error occurs,
** return non-zero.
**
** A missing specifier is not considered an error.
*/
static int parseTimezone(const char *zDate, DateTime *p){
int sgn = 0;
int nHr, nMn;
int c;
while( sqlite3Isspace(*zDate) ){ zDate++; }
p->tz = 0;
c = *zDate;
if( c=='-' ){
sgn = -1;
}else if( c=='+' ){
sgn = +1;
}else if( c=='Z' || c=='z' ){
zDate++;
p->isLocal = 0;
p->isUtc = 1;
goto zulu_time;
}else{
return c!=0;
}
zDate++;
if( getDigits(zDate, "20b:20e", &nHr, &nMn)!=2 ){
return 1;
}
zDate += 5;
p->tz = sgn*(nMn + nHr*60);
if( p->tz==0 ){ /* Forum post 2025-09-17T10:12:14z */
p->isLocal = 0;
p->isUtc = 1;
}
zulu_time:
while( sqlite3Isspace(*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, "20c:20e", &h, &m)!=2 ){
return 1;
}
zDate += 5;
if( *zDate==':' ){
zDate++;
if( getDigits(zDate, "20e", &s)!=1 ){
return 1;
}
zDate += 2;
if( *zDate=='.' && sqlite3Isdigit(zDate[1]) ){
double rScale = 1.0;
zDate++;
while( sqlite3Isdigit(*zDate) ){
ms = ms*10.0 + *zDate - '0';
rScale *= 10.0;
zDate++;
}
ms /= rScale;
/* Truncate to avoid problems with sub-milliseconds
** rounding. https://sqlite.org/forum/forumpost/766a2c9231 */
if( ms>0.999 ) ms = 0.999;
}
}else{
s = 0;
}
if( h==24 && (m!=0 || s!=0 || ms!=0.0) ) return 1;
p->validJD = 0;
p->rawS = 0;
p->validHMS = 1;
p->h = h;
p->m = m;
p->s = s + ms;
if( parseTimezone(zDate, p) ) return 1;
return 0;
}
/*
** Put the DateTime object into its error state.
*/
static void datetimeError(DateTime *p){
memset(p, 0, sizeof(*p));
p->isError = 1;
}
/*
** 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( p->validHMS && p->h==24 ){
p->h = 0;
D = 2;
}
}
if( Y<-4713 || Y>9999 || p->rawS ){
datetimeError(p);
return;
}
if( M<=2 ){
Y--;
M += 12;
}
A = (Y+4800)/100;
B = 38 - A + (A/4);
X1 = 36525*(Y+4716)/100;
X2 = 306001*(M+1)/10000;
p->iJD = (sqlite3_int64)((X1 + X2 + D + B - 1524.5 ) * 86400000);
p->validJD = 1;
if( p->validHMS ){
p->iJD += p->h*3600000 + p->m*60000 + (sqlite3_int64)(p->s*1000 + 0.5);
if( p->tz ){
p->iJD -= p->tz*60000;
p->validYMD = 0;
p->validHMS = 0;
p->tz = 0;
p->isUtc = 1;
p->isLocal = 0;
}
}
}
/*
** Return the number of dates in a specific month.
*/
static int daysOfMonth(int Y, int M){
if( (1<<M) & 0x15aa ){
return 31;
}else if( M!=2 ){
return 30;
}else if( Y%4==0 && (Y%100!=0 || Y%400==0) ){
return 29;
}else{
return 28;
}
}
/*
** Given the YYYY-MM-DD information current in p, determine if there
** is day-of-month overflow and set nFloor to the number of days that
** would need to be subtracted from the date in order to bring the
** date back to the end of the month.
*/
static void computeFloor(DateTime *p){
int mxD; /* Maximum day number for the current month */
assert( p->validYMD || p->isError );
assert( p->D>=0 && p->D<=32 );
assert( p->M>=0 && p->M<=12 );
mxD = daysOfMonth(p->Y, p->M);
p->nFloor = p->D>mxD ? p->D - mxD : 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, "40f-21a-21d", &Y, &M, &D)!=3 ){
return 1;
}
zDate += 10;
while( sqlite3Isspace(*zDate) || 'T'==*(u8*)zDate ){ zDate++; }
if( parseHhMmSs(zDate, p)==0 ){
if( p->h==24 ){
int mxD = daysOfMonth(Y,M);
p->h = 0;
D++;
if( D>mxD ){
D -= mxD;
M++;
if( M>12 ){
M = 1;
Y++;
}
}
}
}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;
computeFloor(p);
if( p->tz ){
computeJD(p);
}
return 0;
}
static void clearYMD_HMS_TZ(DateTime *p); /* Forward declaration */
/*
** Set the time to the current time reported by the VFS.
**
** Return the number of errors.
*/
static int setDateTimeToCurrent(sqlite3_context *context, DateTime *p){
p->iJD = sqlite3StmtCurrentTime(context);
if( p->iJD>0 ){
p->validJD = 1;
p->isUtc = 1;
p->isLocal = 0;
clearYMD_HMS_TZ(p);
return 0;
}else{
return 1;
}
}
/*
** Input "r" is a numeric quantity which might be a julian day number,
** or the number of seconds since 1970. If the value if r is within
** range of a julian day number, install it as such and set validJD.
** If the value is a valid unix timestamp, put it in p->s and set p->rawS.
*/
static void setRawDateNumber(DateTime *p, double r){
p->s = r;
p->rawS = 1;
if( r>=0.0 && r<5373484.5 ){
p->iJD = (sqlite3_int64)(r*86400000.0 + 0.5);
p->validJD = 1;
}
}
/*
** 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
){
double r;
if( parseYyyyMmDd(zDate,p)==0 ){
return 0;
}else if( parseHhMmSs(zDate, p)==0 ){
return 0;
}else if( sqlite3StrICmp(zDate,"now")==0 && sqlite3NotPureFunc(context) ){
return setDateTimeToCurrent(context, p);
}else if( sqlite3AtoF(zDate, &r)>0 ){
setRawDateNumber(p, r);
return 0;
}else if( (sqlite3StrICmp(zDate,"subsec")==0
|| sqlite3StrICmp(zDate,"subsecond")==0)
&& sqlite3NotPureFunc(context) ){
p->useSubsec = 1;
return setDateTimeToCurrent(context, p);
}
return 1;
}
/* The julian day number for 9999-12-31 23:59:59.999 is 5373484.4999999.
** Multiplying this by 86400000 gives 464269060799999 as the maximum value
** for DateTime.iJD.
**
** But some older compilers (ex: gcc 4.2.1 on older Macs) cannot deal with
** such a large integer literal, so we have to encode it.
*/
#define INT_464269060799999 ((((i64)0x1a640)<<32)|0x1072fdff)
/*
** Return TRUE if the given julian day number is within range.
**
** The input is the JulianDay times 86400000.
*/
static int validJulianDay(sqlite3_int64 iJD){
return iJD>=0 && iJD<=INT_464269060799999;
}
/*
** Compute the Year, Month, and Day from the julian day number.
*/
static void computeYMD(DateTime *p){
int Z, alpha, A, B, C, D, E, X1;
if( p->validYMD ) return;
if( !p->validJD ){
p->Y = 2000;
p->M = 1;
p->D = 1;
}else if( !validJulianDay(p->iJD) ){
datetimeError(p);
return;
}else{
Z = (int)((p->iJD + 43200000)/86400000);
alpha = (int)((Z + 32044.75)/36524.25) - 52;
A = Z + 1 + alpha - ((alpha+100)/4) + 25;
B = A + 1524;
C = (int)((B - 122.1)/365.25);
D = (36525*(C&32767))/100;
E = (int)((B-D)/30.6001);
X1 = (int)(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 day_ms, day_min; /* milliseconds, minutes into the day */
if( p->validHMS ) return;
computeJD(p);
day_ms = (int)((p->iJD + 43200000) % 86400000);
p->s = (day_ms % 60000)/1000.0;
day_min = day_ms/60000;
p->m = day_min % 60;
p->h = day_min / 60;
p->rawS = 0;
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->tz = 0;
}
#ifndef SQLITE_OMIT_LOCALTIME
/*
** On recent Windows platforms, the localtime_s() function is available
** as part of the "Secure CRT". It is essentially equivalent to
** localtime_r() available under most POSIX platforms, except that the
** order of the parameters is reversed.
**
** See http://msdn.microsoft.com/en-us/library/a442x3ye(VS.80).aspx.
**
** If the user has not indicated to use localtime_r() or localtime_s()
** already, check for an MSVC build environment that provides
** localtime_s().
*/
#if !HAVE_LOCALTIME_R && !HAVE_LOCALTIME_S \
&& defined(_MSC_VER) && defined(_CRT_INSECURE_DEPRECATE)
#undef HAVE_LOCALTIME_S
#define HAVE_LOCALTIME_S 1
#endif
/*
** The following routine implements the rough equivalent of localtime_r()
** using whatever operating-system specific localtime facility that
** is available. This routine returns 0 on success and
** non-zero on any kind of error.
**
** If the sqlite3GlobalConfig.bLocaltimeFault variable is non-zero then this
** routine will always fail. If bLocaltimeFault is nonzero and
** sqlite3GlobalConfig.xAltLocaltime is not NULL, then xAltLocaltime() is
** invoked in place of the OS-defined localtime() function.
**
** EVIDENCE-OF: R-62172-00036 In this implementation, the standard C
** library function localtime_r() is used to assist in the calculation of
** local time.
*/
static int osLocaltime(time_t *t, struct tm *pTm){
int rc;
#if !HAVE_LOCALTIME_R && !HAVE_LOCALTIME_S
struct tm *pX;
#if SQLITE_THREADSAFE>0
sqlite3_mutex *mutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MAIN);
#endif
sqlite3_mutex_enter(mutex);
pX = localtime(t);
#ifndef SQLITE_UNTESTABLE
if( sqlite3GlobalConfig.bLocaltimeFault ){
if( sqlite3GlobalConfig.xAltLocaltime!=0
&& 0==sqlite3GlobalConfig.xAltLocaltime((const void*)t,(void*)pTm)
){
pX = pTm;
}else{
pX = 0;
}
}
#endif
if( pX ) *pTm = *pX;
#if SQLITE_THREADSAFE>0
sqlite3_mutex_leave(mutex);
#endif
rc = pX==0;
#else
#ifndef SQLITE_UNTESTABLE
if( sqlite3GlobalConfig.bLocaltimeFault ){
if( sqlite3GlobalConfig.xAltLocaltime!=0 ){
return sqlite3GlobalConfig.xAltLocaltime((const void*)t,(void*)pTm);
}else{
return 1;
}
}
#endif
#if HAVE_LOCALTIME_R
rc = localtime_r(t, pTm)==0;
#else
rc = localtime_s(pTm, t);
#endif /* HAVE_LOCALTIME_R */
#endif /* HAVE_LOCALTIME_R || HAVE_LOCALTIME_S */
return rc;
}
#endif /* SQLITE_OMIT_LOCALTIME */
#ifndef SQLITE_OMIT_LOCALTIME
/*
** Assuming the input DateTime is UTC, move it to its localtime equivalent.
*/
static int toLocaltime(
DateTime *p, /* Date at which to calculate offset */
sqlite3_context *pCtx /* Write error here if one occurs */
){
time_t t;
struct tm sLocal;
int iYearDiff;
/* Initialize the contents of sLocal to avoid a compiler warning. */
memset(&sLocal, 0, sizeof(sLocal));
computeJD(p);
if( p->iJD<2108667600*(i64)100000 /* 1970-01-01 */
|| p->iJD>2130141456*(i64)100000 /* 2038-01-18 */
){
/* EVIDENCE-OF: R-55269-29598 The localtime_r() C function normally only
** works for years between 1970 and 2037. For dates outside this range,
** SQLite attempts to map the year into an equivalent year within this
** range, do the calculation, then map the year back.
*/
DateTime x = *p;
computeYMD_HMS(&x);
iYearDiff = (2000 + x.Y%4) - x.Y;
x.Y += iYearDiff;
x.validJD = 0;
computeJD(&x);
t = (time_t)(x.iJD/1000 - 21086676*(i64)10000);
}else{
iYearDiff = 0;
t = (time_t)(p->iJD/1000 - 21086676*(i64)10000);
}
if( osLocaltime(&t, &sLocal) ){
sqlite3_result_error(pCtx, "local time unavailable", -1);
return SQLITE_ERROR;
}
p->Y = sLocal.tm_year + 1900 - iYearDiff;
p->M = sLocal.tm_mon + 1;
p->D = sLocal.tm_mday;
p->h = sLocal.tm_hour;
p->m = sLocal.tm_min;
p->s = sLocal.tm_sec + (p->iJD%1000)*0.001;
p->validYMD = 1;
p->validHMS = 1;
p->validJD = 0;
p->rawS = 0;
p->tz = 0;
p->isError = 0;
return SQLITE_OK;
}
#endif /* SQLITE_OMIT_LOCALTIME */
/*
** The following table defines various date transformations of the form
**
** 'NNN days'
**
** Where NNN is an arbitrary floating-point number and "days" can be one
** of several units of time.
*/
static const struct {
u8 nName; /* Length of the name */
char zName[7]; /* Name of the transformation */
float rLimit; /* Maximum NNN value for this transform */
float rXform; /* Constant used for this transform */
} aXformType[] = {
/* 0 */ { 6, "second", 4.6427e+14, 1.0 },
/* 1 */ { 6, "minute", 7.7379e+12, 60.0 },
/* 2 */ { 4, "hour", 1.2897e+11, 3600.0 },
/* 3 */ { 3, "day", 5373485.0, 86400.0 },
/* 4 */ { 5, "month", 176546.0, 2592000.0 },
/* 5 */ { 4, "year", 14713.0, 31536000.0 },
};
/*
** If the DateTime p is raw number, try to figure out if it is
** a julian day number of a unix timestamp. Set the p value
** appropriately.
*/
static void autoAdjustDate(DateTime *p){
if( !p->rawS || p->validJD ){
p->rawS = 0;
}else if( p->s>=-21086676*(i64)10000 /* -4713-11-24 12:00:00 */
&& p->s<=(25340230*(i64)10000)+799 /* 9999-12-31 23:59:59 */
){
double r = p->s*1000.0 + 210866760000000.0;
clearYMD_HMS_TZ(p);
p->iJD = (sqlite3_int64)(r + 0.5);
p->validJD = 1;
p->rawS = 0;
}
}
/*
** 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
** +/-YYYY-MM-DD HH:MM:SS.SSS
** ceiling
** floor
** start of month
** start of year
** start of week
** start of day
** weekday N
** unixepoch
** auto
** localtime
** utc
** subsec
** subsecond
**
** Return 0 on success and 1 if there is any kind of error. If the error
** is in a system call (i.e. localtime()), then an error message is written
** to context pCtx. If the error is an unrecognized modifier, no error is
** written to pCtx.
*/
static int parseModifier(
sqlite3_context *pCtx, /* Function context */
const char *z, /* The text of the modifier */
int n, /* Length of zMod in bytes */
DateTime *p, /* The date/time value to be modified */
int idx /* Parameter index of the modifier */
){
int rc = 1;
double r;
switch(sqlite3UpperToLower[(u8)z[0]] ){
case 'a': {
/*
** auto
**
** If rawS is available, then interpret as a julian day number, or
** a unix timestamp, depending on its magnitude.
*/
if( sqlite3_stricmp(z, "auto")==0 ){
if( idx>1 ) return 1; /* IMP: R-33611-57934 */
autoAdjustDate(p);
rc = 0;
}
break;
}
case 'c': {
/*
** ceiling
**
** Resolve day-of-month overflow by rolling forward into the next
** month. As this is the default action, this modifier is really
** a no-op that is only included for symmetry. See "floor".
*/
if( sqlite3_stricmp(z, "ceiling")==0 ){
computeJD(p);
clearYMD_HMS_TZ(p);
rc = 0;
p->nFloor = 0;
}
break;
}
case 'e': {
/*
** end of day
** end of month
** end of year
**
** Move the date forwards to the last millisecond of the current
** day, month or year.
*/
if( sqlite3_strnicmp(z, "end of ", 7)!=0 ){
break;
}
if( !p->validJD && !p->validYMD && !p->validHMS ) break;
z += 7;
computeYMD(p);
p->validHMS = 1;
p->h = 23;
p->m = 59;
p->s = 59.999;
p->rawS = 0;
p->tz = 0;
p->validJD = 0;
if( sqlite3_stricmp(z,"month")==0 ){
p->D = 1;
p->M++;
if( p->M>12 ){
p->Y++;
p->M = 1;
}
computeFloor(p);
computeJD(p);
p->iJD -= (p->nFloor+1)*86400000;
clearYMD_HMS_TZ(p);
rc = 0;
}else if( sqlite3_stricmp(z,"year")==0 ){
p->M = 12;
p->D = 31;
rc = 0;
}else if( sqlite3_stricmp(z,"day")==0 ){
rc = 0;
}
break;
}
case 'f': {
/*
** floor
**
** Resolve day-of-month overflow by rolling back to the end of the
** previous month.
*/
if( sqlite3_stricmp(z, "floor")==0 ){
computeJD(p);
p->iJD -= p->nFloor*86400000;
clearYMD_HMS_TZ(p);
rc = 0;
}
break;
}
case 'j': {
/*
** julianday
**
** Always interpret the prior number as a julian-day value. If this
** is not the first modifier, or if the prior argument is not a numeric
** value in the allowed range of julian day numbers understood by
** SQLite (0..5373484.5) then the result will be NULL.
*/
if( sqlite3_stricmp(z, "julianday")==0 ){
if( idx>1 ) return 1; /* IMP: R-31176-64601 */
if( p->validJD && p->rawS ){
rc = 0;
p->rawS = 0;
}
}
break;
}
#ifndef SQLITE_OMIT_LOCALTIME
case 'l': {
/* localtime
**
** Assuming the current time value is UTC (a.k.a. GMT), shift it to
** show local time.
*/
if( sqlite3_stricmp(z, "localtime")==0 && sqlite3NotPureFunc(pCtx) ){
rc = p->isLocal ? SQLITE_OK : toLocaltime(p, pCtx);
p->isUtc = 0;
p->isLocal = 1;
}
break;
}
#endif
case 'u': {
/*
** unixepoch
**
** Treat the current value of p->s as the number of
** seconds since 1970. Convert to a real julian day number.
*/
if( sqlite3_stricmp(z, "unixepoch")==0 && p->rawS ){
if( idx>1 ) return 1; /* IMP: R-49255-55373 */
r = p->s*1000.0 + 210866760000000.0;
if( r>=0.0 && r<464269060800000.0 ){
clearYMD_HMS_TZ(p);
p->iJD = (sqlite3_int64)(r + 0.5);
p->validJD = 1;
p->rawS = 0;
rc = 0;
}
}
#ifndef SQLITE_OMIT_LOCALTIME
else if( sqlite3_stricmp(z, "utc")==0 && sqlite3NotPureFunc(pCtx) ){
if( p->isUtc==0 ){
i64 iOrigJD; /* Original localtime */
i64 iGuess; /* Guess at the corresponding utc time */
int cnt = 0; /* Safety to prevent infinite loop */
i64 iErr; /* Guess is off by this much */
computeJD(p);
iGuess = iOrigJD = p->iJD;
iErr = 0;
do{
DateTime new;
memset(&new, 0, sizeof(new));
iGuess -= iErr;
new.iJD = iGuess;
new.validJD = 1;
rc = toLocaltime(&new, pCtx);
if( rc ) return rc;
computeJD(&new);
iErr = new.iJD - iOrigJD;
}while( iErr && cnt++<3 );
memset(p, 0, sizeof(*p));
p->iJD = iGuess;
p->validJD = 1;
p->isUtc = 1;
p->isLocal = 0;
}
rc = SQLITE_OK;
}
#endif
break;
}
case 'w': {
/*
** weekday N
** weekday -N
**
** Move the date forward (for N>=0) or backward (for N<=-0) to the
** same time on the next/previous occurrence of weekday abs(N)
** where 0==Sunday, 1==Monday, and so forth. If the date is already
** on the appropriate weekday, this is a no-op.
*/
if( sqlite3_strnicmp(z, "weekday ", 8)==0
&& sqlite3AtoF(&z[8], &r)>0
&& r>=-6.0 && r<=6.0
&& sqlite3RealSameAsInt(r,(i64)(n=(int)r))
){
sqlite3_int64 Z;
computeYMD_HMS(p);
p->tz = 0;
p->validJD = 0;
computeJD(p);
Z = ((p->iJD + 129600000)/86400000) % 7;
if( n<0 ) n = -n;
if( Z!=n ){
if( Z>n ) Z -= 7;
p->iJD += (n - Z)*86400000;
if( strchr(z+8,'-')!=0 ) p->iJD -= 7*86400000;
}
clearYMD_HMS_TZ(p);
rc = 0;
}
break;
}
case 's': {
/*
** start of day
** start of month
** start of year
**
** Move the date backwards to the beginning of the current day,
** or month or year.
**
** subsecond
** subsec
**
** Show subsecond precision in the output of datetime() and
** unixepoch() and strftime('%s').
*/
if( sqlite3_strnicmp(z, "start of ", 9)!=0 ){
if( sqlite3_stricmp(z, "subsec")==0
|| sqlite3_stricmp(z, "subsecond")==0
){
p->useSubsec = 1;
rc = 0;
}
break;
}
if( !p->validJD && !p->validYMD && !p->validHMS ) break;
z += 9;
computeYMD(p);
p->validHMS = 1;
p->h = p->m = 0;
p->s = 0.0;
p->rawS = 0;
p->tz = 0;
p->validJD = 0;