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campo-sirio/sqlite/date.c
guy e883f21fe8 Patch level : 2.2 
Files correlati     : sqlite
Ricompilazione Demo : [ ]
Commento            :
Passaggio da Sqlite 2 a Sqlite 3.3.5


git-svn-id: svn://10.65.10.50/trunk@13902 c028cbd2-c16b-5b4b-a496-9718f37d4682
2006-04-13 12:44:29 +00:00

999 lines
24 KiB
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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.
**
** $Id: date.c,v 1.2 2006-04-13 12:44:29 guy 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.
**
** 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 "os.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;
p->validYMD = 0;
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->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(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(&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;
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;
struct tm *pTm;
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;
sqlite3OsEnterMutex();
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;
sqlite3OsLeaveMutex();
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);
if( n<=0 ) break;
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(int argc, sqlite3_value **argv, DateTime *p){
int i;
if( argc==0 ) return 1;
if( SQLITE_NULL==sqlite3_value_type(argv[0]) ||
parseDateOrTime((char*)sqlite3_value_text(argv[0]), p) ) return 1;
for(i=1; i<argc; i++){
if( SQLITE_NULL==sqlite3_value_type(argv[i]) ||
parseModifier((char*)sqlite3_value_text(argv[i]), p) ) return 1;
}
return 0;
}
/*
** The following routines implement the various date and time functions
** of SQLite.
*/
/*
** julianday( TIMESTRING, MOD, MOD, ...)
**
** Return the julian day number of the date specified in the arguments
*/
static void juliandayFunc(
sqlite3_context *context,
int argc,
sqlite3_value **argv
){
DateTime x;
if( isDate(argc, argv, &x)==0 ){
computeJD(&x);
sqlite3_result_double(context, x.rJD);
}
}
/*
** datetime( TIMESTRING, MOD, MOD, ...)
**
** Return YYYY-MM-DD HH:MM:SS
*/
static void datetimeFunc(
sqlite3_context *context,
int argc,
sqlite3_value **argv
){
DateTime x;
if( isDate(argc, argv, &x)==0 ){
char zBuf[100];
computeYMD_HMS(&x);
sprintf(zBuf, "%04d-%02d-%02d %02d:%02d:%02d",x.Y, x.M, x.D, x.h, x.m,
(int)(x.s));
sqlite3_result_text(context, zBuf, -1, 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(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, 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(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, 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;
int n, i, j;
char *z;
const char *zFmt = (const char*)sqlite3_value_text(argv[0]);
char zBuf[100];
if( zFmt==0 || isDate(argc-1, argv+1, &x) ) return;
for(i=0, n=1; zFmt[i]; i++, n++){
if( zFmt[i]=='%' ){
switch( zFmt[i+1] ){
case 'd':
case 'H':
case 'm':
case 'M':
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{
z = sqliteMalloc( 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': sprintf(&z[j],"%02d",x.D); j+=2; break;
case 'f': {
int s = x.s;
int ms = (x.s - s)*1000.0;
sprintf(&z[j],"%02d.%03d",s,ms);
j += strlen(&z[j]);
break;
}
case 'H': sprintf(&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;
if( zFmt[i]=='W' ){
int wd; /* 0=Monday, 1=Tuesday, ... 6=Sunday */
wd = ((int)(x.rJD+0.5)) % 7;
sprintf(&z[j],"%02d",(nDay+7-wd)/7);
j += 2;
}else{
sprintf(&z[j],"%03d",nDay+1);
j += 3;
}
break;
}
case 'J': sprintf(&z[j],"%.16g",x.rJD); j+=strlen(&z[j]); break;
case 'm': sprintf(&z[j],"%02d",x.M); j+=2; break;
case 'M': sprintf(&z[j],"%02d",x.m); j+=2; break;
case 's': {
sprintf(&z[j],"%d",(int)((x.rJD-2440587.5)*86400.0 + 0.5));
j += strlen(&z[j]);
break;
}
case 'S': sprintf(&z[j],"%02d",(int)(x.s+0.5)); j+=2; break;
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, SQLITE_TRANSIENT);
if( z!=zBuf ){
sqliteFree(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();
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();
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();
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
sqlite3OsEnterMutex();
strftime(zBuf, 20, zFormat, gmtime(&t));
sqlite3OsLeaveMutex();
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, 0, 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
}
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