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elinks/src/protocol/date.c

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/* Parser of HTTP date */
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <stdlib.h>
#include <string.h>
#ifdef TIME_WITH_SYS_TIME
#ifdef HAVE_SYS_TIME_H
#include <sys/time.h>
#endif
#ifdef HAVE_TIME_H
#include <time.h>
#endif
#else
#if defined(TM_IN_SYS_TIME) && defined(HAVE_SYS_TIME_H)
#include <sys/time.h>
#elif defined(HAVE_TIME_H)
#include <time.h>
#endif
#endif
#include "elinks.h"
#include "protocol/date.h"
#include "util/conv.h"
#include "util/time.h"
/*
* 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
*/
int
parse_year(const unsigned char **date_p, unsigned char *end)
{
const unsigned char *date = *date_p;
int year;
if ((end && date + 1 >= end)
|| !isdigit(date[0])
|| !isdigit(date[1]))
return -1;
year = (date[0] - '0') * 10 + date[1] - '0';
if ((!end || date + 3 < end)
&& isdigit(date[2])
&& isdigit(date[3])) {
/* Four digits date */
year = year * 10 + date[2] - '0';
year = year * 10 + date[3] - '0' - 1900;
date += 4;
} else if (year < 70) {
/* Assuming the epoch starting at 1.1.1970 so it's already next
* century. --wget */
year += 100;
date += 2;
}
*date_p = date;
return year;
}
int
parse_month(const unsigned char **buf, unsigned char *end)
{
const unsigned char *month = *buf;
int monthnum;
/* Check that the buffer has atleast 3 chars. */
if ((end && month + 2 > end)
|| !month[0] || !month[1] || !month[2])
return -1;
monthnum = month2num(month);
if (monthnum != -1)
*buf += 3;
return monthnum;
}
/* Return day number. */
int
parse_day(const unsigned char **date_p, unsigned char *end)
{
const unsigned char *date = *date_p;
int day;
if ((end && date >= end) || !isdigit(*date))
return 32;
day = *date++ - '0';
if ((!end || date < end) && isdigit(*date)) {
day = day * 10 + *date++ - '0';
}
*date_p = date;
return day;
}
int
parse_time(const unsigned char **time, struct tm *tm, unsigned char *end)
{
unsigned char h1, h2, m1, m2;
const unsigned char *date = *time;
#define check_time(tm) \
((tm)->tm_hour <= 23 && (tm)->tm_min <= 59 && (tm)->tm_sec <= 59)
/* Eat HH:MM */
if (end && date + 5 > end)
return 0;
h1 = *date++; if (!isdigit(h1)) return 0;
h2 = *date++; if (!isdigit(h2)) return 0;
if (*date++ != ':') return 0;
m1 = *date++; if (!isdigit(m1)) return 0;
m2 = *date++; if (!isdigit(m2)) return 0;
tm->tm_hour = (h1 - '0') * 10 + h2 - '0';
tm->tm_min = (m1 - '0') * 10 + m2 - '0';
/* Eat :SS or [PA]M or nothing */
if (end && date + 2 >= end) {
*time = date;
return check_time(tm);
}
if (*date == ':') {
unsigned char s1, s2;
date++;
if (end && date + 2 >= end)
return 0;
s1 = *date++; if (!isdigit(s1)) return 0;
s2 = *date++; if (!isdigit(s2)) return 0;
tm->tm_sec = (s1 - '0') * 10 + s2 - '0';
} else if (*date == 'A' || *date == 'P') {
/* Adjust hour from AM/PM. The sequence goes 11:00AM, 12:00PM,
* 01:00PM ... 11:00PM, 12:00AM, 01:00AM. --wget */
if (tm->tm_hour == 12)
tm->tm_hour = 0;
if (*date++ == 'P')
tm->tm_hour += 12;
if (*date++ != 'M')
return 0;
}
*time = date;
return check_time(tm);
}
static time_t
my_timegm(struct tm *tm)
{
time_t t = 0;
/* Okay, the next part of the code is somehow problematic. Now, we use
* own code for calculating the number of seconds from 1.1.1970,
* brought here by SC from w3m. I don't like it a lot, but it's 100%
* portable, it's faster and it's shorter. --pasky */
#if 0
#ifdef HAVE_TIMEGM
t = timegm(tm);
#else
/* Since mktime thinks we have localtime, we need a wrapper
* to handle GMT. */
/* FIXME: It was reported that it doesn't work somewhere :/. */
{
unsigned char *tz = getenv("TZ");
if (tz && *tz) {
/* Temporary disable timezone in-place. */
unsigned char tmp = *tz;
*tz = '\0';
tzset();
t = mktime(tm);
*tz = tmp;
tzset();
} else {
/* Already GMT, cool! */
t = mktime(tm);
}
}
#endif
#else
/* Following code was borrowed from w3m, and its developers probably
* borrowed it from somewhere else as well, altough they didn't bother
* to mention that. */ /* Actually, same code appears to be in lynx as
* well.. oh well. :) */
/* See README.timegm for explanation about how this works. */
tm->tm_mon -= 2;
if (tm->tm_mon < 0) {
tm->tm_mon += 12;
tm->tm_year--;
}
tm->tm_mon *= 153; tm->tm_mon += 2;
tm->tm_year -= 68;
tm->tm_mday += tm->tm_year * 1461 / 4;
tm->tm_mday += ((tm->tm_mon / 5) - 672);
t = ((tm->tm_mday * 60 * 60 * 24) +
(tm->tm_hour * 60 * 60) +
(tm->tm_min * 60) +
tm->tm_sec);
#endif
if (t == (time_t) -1) return 0;
return t;
}
time_t
parse_date(unsigned char **date_pos, unsigned char *end,
int update_pos, int skip_week_day)
{
#define skip_time_sep(date, end) \
do { \
const unsigned char *start = (date); \
while ((!(end) || (date) < (end)) \
&& (*(date) == ' ' || *(date) == '-')) \
(date)++; \
if (date == start) return 0; \
} while (0)
struct tm tm;
const unsigned char *date = (const unsigned char *) *date_pos;
if (!date) return 0;
if (skip_week_day) {
/* Skip day-of-week */
for (; (!end || date < end) && *date != ' '; date++)
if (!*date) return 0;
/* As pasky said who cares if we allow '-'s here? */
skip_time_sep(date, end);
}
if (isdigit(*date)) {
/* RFC 1036 / RFC 1123 */
/* Eat day */
/* date++; */
tm.tm_mday = parse_day(&date, end);
if (tm.tm_mday > 31) return 0;
skip_time_sep(date, end);
/* Eat month */
tm.tm_mon = parse_month(&date, end);
if (tm.tm_mon < 0) return 0;
skip_time_sep(date, end);
/* Eat year */
tm.tm_year = parse_year(&date, end);
if (tm.tm_year < 0) return 0;
skip_time_sep(date, end);
/* Eat time */
if (!parse_time(&date, &tm, end)) return 0;
} else {
/* ANSI C's asctime() format */
/* Eat month */
tm.tm_mon = parse_month(&date, end);
if (tm.tm_mon < 0) return 0;
/* I know, we shouldn't allow '-', but who cares ;). --pasky */
skip_time_sep(date, end);
/* Eat day */
tm.tm_mday = parse_day(&date, end);
if (tm.tm_mday > 31) return 0;
skip_time_sep(date, end);
/* Eat time */
if (!parse_time(&date, &tm, end)) return 0;
skip_time_sep(date, end);
/* Eat year */
tm.tm_year = parse_year(&date, end);
if (tm.tm_year < 0) return 0;
}
#undef skip_time_sep
if (update_pos)
*date_pos = (unsigned char *) date;
return (time_t) my_timegm(&tm);
}