curl/lib/parsedate.c
2008-09-29 23:22:41 +00:00

443 lines
12 KiB
C

/***************************************************************************
* _ _ ____ _
* Project ___| | | | _ \| |
* / __| | | | |_) | |
* | (__| |_| | _ <| |___
* \___|\___/|_| \_\_____|
*
* Copyright (C) 1998 - 2008, Daniel Stenberg, <daniel@haxx.se>, et al.
*
* This software is licensed as described in the file COPYING, which
* you should have received as part of this distribution. The terms
* are also available at http://curl.haxx.se/docs/copyright.html.
*
* You may opt to use, copy, modify, merge, publish, distribute and/or sell
* copies of the Software, and permit persons to whom the Software is
* furnished to do so, under the terms of the COPYING file.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
* $Id$
***************************************************************************/
/*
A brief summary of the date string formats this parser groks:
RFC 2616 3.3.1
Sun, 06 Nov 1994 08:49:37 GMT ; RFC 822, updated by RFC 1123
Sunday, 06-Nov-94 08:49:37 GMT ; RFC 850, obsoleted by RFC 1036
Sun Nov 6 08:49:37 1994 ; ANSI C's asctime() format
we support dates without week day name:
06 Nov 1994 08:49:37 GMT
06-Nov-94 08:49:37 GMT
Nov 6 08:49:37 1994
without the time zone:
06 Nov 1994 08:49:37
06-Nov-94 08:49:37
weird order:
1994 Nov 6 08:49:37 (GNU date fails)
GMT 08:49:37 06-Nov-94 Sunday
94 6 Nov 08:49:37 (GNU date fails)
time left out:
1994 Nov 6
06-Nov-94
Sun Nov 6 94
unusual separators:
1994.Nov.6
Sun/Nov/6/94/GMT
commonly used time zone names:
Sun, 06 Nov 1994 08:49:37 CET
06 Nov 1994 08:49:37 EST
time zones specified using RFC822 style:
Sun, 12 Sep 2004 15:05:58 -0700
Sat, 11 Sep 2004 21:32:11 +0200
compact numerical date strings:
20040912 15:05:58 -0700
20040911 +0200
*/
#include "setup.h"
#include <stdio.h>
#include <ctype.h>
#include <string.h>
#ifdef HAVE_STDLIB_H
#include <stdlib.h> /* for strtol() */
#endif
#include <curl/curl.h>
#include "parsedate.h"
const char * const Curl_wkday[] =
{"Mon", "Tue", "Wed", "Thu", "Fri", "Sat", "Sun"};
static const char * const weekday[] =
{ "Monday", "Tuesday", "Wednesday", "Thursday",
"Friday", "Saturday", "Sunday" };
const char * const Curl_month[]=
{ "Jan", "Feb", "Mar", "Apr", "May", "Jun",
"Jul", "Aug", "Sep", "Oct", "Nov", "Dec" };
struct tzinfo {
const char *name;
int offset; /* +/- in minutes */
};
/* Here's a bunch of frequently used time zone names. These were supported
by the old getdate parser. */
#define tDAYZONE -60 /* offset for daylight savings time */
static const struct tzinfo tz[]= {
{"GMT", 0}, /* Greenwich Mean */
{"UTC", 0}, /* Universal (Coordinated) */
{"WET", 0}, /* Western European */
{"BST", 0 tDAYZONE}, /* British Summer */
{"WAT", 60}, /* West Africa */
{"AST", 240}, /* Atlantic Standard */
{"ADT", 240 tDAYZONE}, /* Atlantic Daylight */
{"EST", 300}, /* Eastern Standard */
{"EDT", 300 tDAYZONE}, /* Eastern Daylight */
{"CST", 360}, /* Central Standard */
{"CDT", 360 tDAYZONE}, /* Central Daylight */
{"MST", 420}, /* Mountain Standard */
{"MDT", 420 tDAYZONE}, /* Mountain Daylight */
{"PST", 480}, /* Pacific Standard */
{"PDT", 480 tDAYZONE}, /* Pacific Daylight */
{"YST", 540}, /* Yukon Standard */
{"YDT", 540 tDAYZONE}, /* Yukon Daylight */
{"HST", 600}, /* Hawaii Standard */
{"HDT", 600 tDAYZONE}, /* Hawaii Daylight */
{"CAT", 600}, /* Central Alaska */
{"AHST", 600}, /* Alaska-Hawaii Standard */
{"NT", 660}, /* Nome */
{"IDLW", 720}, /* International Date Line West */
{"CET", -60}, /* Central European */
{"MET", -60}, /* Middle European */
{"MEWT", -60}, /* Middle European Winter */
{"MEST", -60 tDAYZONE}, /* Middle European Summer */
{"CEST", -60 tDAYZONE}, /* Central European Summer */
{"MESZ", -60 tDAYZONE}, /* Middle European Summer */
{"FWT", -60}, /* French Winter */
{"FST", -60 tDAYZONE}, /* French Summer */
{"EET", -120}, /* Eastern Europe, USSR Zone 1 */
{"WAST", -420}, /* West Australian Standard */
{"WADT", -420 tDAYZONE}, /* West Australian Daylight */
{"CCT", -480}, /* China Coast, USSR Zone 7 */
{"JST", -540}, /* Japan Standard, USSR Zone 8 */
{"EAST", -600}, /* Eastern Australian Standard */
{"EADT", -600 tDAYZONE}, /* Eastern Australian Daylight */
{"GST", -600}, /* Guam Standard, USSR Zone 9 */
{"NZT", -720}, /* New Zealand */
{"NZST", -720}, /* New Zealand Standard */
{"NZDT", -720 tDAYZONE}, /* New Zealand Daylight */
{"IDLE", -720}, /* International Date Line East */
};
/* returns:
-1 no day
0 monday - 6 sunday
*/
static int checkday(const char *check, size_t len)
{
int i;
const char * const *what;
bool found= FALSE;
if(len > 3)
what = &weekday[0];
else
what = &Curl_wkday[0];
for(i=0; i<7; i++) {
if(curl_strequal(check, what[0])) {
found=TRUE;
break;
}
what++;
}
return found?i:-1;
}
static int checkmonth(const char *check)
{
int i;
const char * const *what;
bool found= FALSE;
what = &Curl_month[0];
for(i=0; i<12; i++) {
if(curl_strequal(check, what[0])) {
found=TRUE;
break;
}
what++;
}
return found?i:-1; /* return the offset or -1, no real offset is -1 */
}
/* return the time zone offset between GMT and the input one, in number
of seconds or -1 if the timezone wasn't found/legal */
static int checktz(const char *check)
{
unsigned int i;
const struct tzinfo *what;
bool found= FALSE;
what = tz;
for(i=0; i< sizeof(tz)/sizeof(tz[0]); i++) {
if(curl_strequal(check, what->name)) {
found=TRUE;
break;
}
what++;
}
return found?what->offset*60:-1;
}
static void skip(const char **date)
{
/* skip everything that aren't letters or digits */
while(**date && !ISALNUM(**date))
(*date)++;
}
enum assume {
DATE_MDAY,
DATE_YEAR,
DATE_TIME
};
/* struct tm to time since epoch in GMT time zone.
* This is similar to the standard mktime function but for GMT only, and
* doesn't suffer from the various bugs and portability problems that
* some systems' implementations have.
*/
static time_t my_timegm(struct tm * tm)
{
static const int month_days_cumulative [12] =
{ 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334 };
int month, year, leap_days;
if(tm->tm_year < 70)
/* we don't support years before 1970 as they will cause this function
to return a negative value */
return -1;
year = tm->tm_year + 1900;
month = tm->tm_mon;
if (month < 0) {
year += (11 - month) / 12;
month = 11 - (11 - month) % 12;
}
else if (month >= 12) {
year -= month / 12;
month = month % 12;
}
leap_days = year - (tm->tm_mon <= 1);
leap_days = ((leap_days / 4) - (leap_days / 100) + (leap_days / 400)
- (1969 / 4) + (1969 / 100) - (1969 / 400));
return ((((time_t) (year - 1970) * 365
+ leap_days + month_days_cumulative [month] + tm->tm_mday - 1) * 24
+ tm->tm_hour) * 60 + tm->tm_min) * 60 + tm->tm_sec;
}
static time_t parsedate(const char *date)
{
time_t t = 0;
int wdaynum=-1; /* day of the week number, 0-6 (mon-sun) */
int monnum=-1; /* month of the year number, 0-11 */
int mdaynum=-1; /* day of month, 1 - 31 */
int hournum=-1;
int minnum=-1;
int secnum=-1;
int yearnum=-1;
int tzoff=-1;
struct tm tm;
enum assume dignext = DATE_MDAY;
const char *indate = date; /* save the original pointer */
int part = 0; /* max 6 parts */
while(*date && (part < 6)) {
bool found=FALSE;
skip(&date);
if(ISALPHA(*date)) {
/* a name coming up */
char buf[32]="";
size_t len;
sscanf(date, "%31[ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz]",
buf);
len = strlen(buf);
if(wdaynum == -1) {
wdaynum = checkday(buf, len);
if(wdaynum != -1)
found = TRUE;
}
if(!found && (monnum == -1)) {
monnum = checkmonth(buf);
if(monnum != -1)
found = TRUE;
}
if(!found && (tzoff == -1)) {
/* this just must be a time zone string */
tzoff = checktz(buf);
if(tzoff != -1)
found = TRUE;
}
if(!found)
return -1; /* bad string */
date += len;
}
else if(ISDIGIT(*date)) {
/* a digit */
int val;
char *end;
if((secnum == -1) &&
(3 == sscanf(date, "%02d:%02d:%02d", &hournum, &minnum, &secnum))) {
/* time stamp! */
date += 8;
found = TRUE;
}
else {
val = (int)strtol(date, &end, 10);
if((tzoff == -1) &&
((end - date) == 4) &&
(val <= 1400) &&
(indate< date) &&
((date[-1] == '+' || date[-1] == '-'))) {
/* four digits and a value less than or equal to 1400 (to take into
account all sorts of funny time zone diffs) and it is preceeded
with a plus or minus. This is a time zone indication. 1400 is
picked since +1300 is frequently used and +1400 is mentioned as
an edge number in the document "ISO C 200X Proposal: Timezone
Functions" at http://david.tribble.com/text/c0xtimezone.html If
anyone has a more authoritative source for the exact maximum time
zone offsets, please speak up! */
found = TRUE;
tzoff = (val/100 * 60 + val%100)*60;
/* the + and - prefix indicates the local time compared to GMT,
this we need ther reversed math to get what we want */
tzoff = date[-1]=='+'?-tzoff:tzoff;
}
if(((end - date) == 8) &&
(yearnum == -1) &&
(monnum == -1) &&
(mdaynum == -1)) {
/* 8 digits, no year, month or day yet. This is YYYYMMDD */
found = TRUE;
yearnum = val/10000;
monnum = (val%10000)/100-1; /* month is 0 - 11 */
mdaynum = val%100;
}
if(!found && (dignext == DATE_MDAY) && (mdaynum == -1)) {
if((val > 0) && (val<32)) {
mdaynum = val;
found = TRUE;
}
dignext = DATE_YEAR;
}
if(!found && (dignext == DATE_YEAR) && (yearnum == -1)) {
yearnum = val;
found = TRUE;
if(yearnum < 1900) {
if(yearnum > 70)
yearnum += 1900;
else
yearnum += 2000;
}
if(mdaynum == -1)
dignext = DATE_MDAY;
}
if(!found)
return -1;
date = end;
}
}
part++;
}
if(-1 == secnum)
secnum = minnum = hournum = 0; /* no time, make it zero */
if((-1 == mdaynum) ||
(-1 == monnum) ||
(-1 == yearnum))
/* lacks vital info, fail */
return -1;
#if SIZEOF_TIME_T < 5
/* 32 bit time_t can only hold dates to the beginning of 2038 */
if(yearnum > 2037)
return 0x7fffffff;
#endif
tm.tm_sec = secnum;
tm.tm_min = minnum;
tm.tm_hour = hournum;
tm.tm_mday = mdaynum;
tm.tm_mon = monnum;
tm.tm_year = yearnum - 1900;
tm.tm_wday = 0;
tm.tm_yday = 0;
tm.tm_isdst = 0;
/* my_timegm() returns a time_t. time_t is often 32 bits, even on many
architectures that feature 64 bit 'long'.
Some systems have 64 bit time_t and deal with years beyond 2038. However,
even on some of the systems with 64 bit time_t mktime() returns -1 for
dates beyond 03:14:07 UTC, January 19, 2038. (Such as AIX 5100-06)
*/
t = my_timegm(&tm);
/* time zone adjust (cast t to int to compare to negative one) */
if(-1 != (int)t) {
/* Add the time zone diff between local time zone and GMT. */
long delta = (long)(tzoff!=-1?tzoff:0);
if((delta>0) && (t + delta < t))
return -1; /* time_t overflow */
t += delta;
}
return t;
}
time_t curl_getdate(const char *p, const time_t *now)
{
(void)now;
return parsedate(p);
}