rfc822-date.c revision 0768959c7e9fc363a353ce45605e4dbd1f46f29e
/* Copyright (C) 2002 Timo Sirainen */
#include "lib.h"
#include "utc-offset.h"
#include "utc-mktime.h"
#include "rfc822-date.h"
#include "rfc822-tokenize.h"
#include <ctype.h>
static const char *month_names[] = {
"Jan", "Feb", "Mar", "Apr", "May", "Jun",
"Jul", "Aug", "Sep", "Oct", "Nov", "Dec"
};
static const char *weekday_names[] = {
"Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"
};
static int parse_timezone(const char *str, size_t len)
{
int offset;
char chr;
if (len == 5 && (*str == '+' || *str == '-')) {
/* numeric offset */
if (!i_isdigit(str[1]) || !i_isdigit(str[2]) ||
!i_isdigit(str[3]) || !i_isdigit(str[4]))
return FALSE;
offset = (str[1]-'0') * 1000 + (str[2]-'0') * 100 +
(str[3]-'0') * 10 + (str[4]-'0');
return *str == '+' ? offset : -offset;
}
if (len == 1) {
/* military zone - handle them the correct way, not as
RFC822 says. RFC2822 though suggests that they'd be
considered as unspecified.. */
chr = i_toupper(*str);
if (chr < 'J')
return (*str-'A'+1) * 60;
if (chr == 'J')
return 0;
if (chr <= 'M')
return (*str-'A') * 60;
if (chr < 'Z')
return ('M'-*str) * 60;
return 0;
}
if (len == 2 && i_toupper(str[0]) == 'U' && i_toupper(str[1]) == 'T') {
/* UT - Universal Time */
return 0;
}
if (len == 3) {
/* GMT | [ECMP][DS]T */
if (str[2] != 'T')
return 0;
switch (i_toupper(*str)) {
case 'E':
offset = -5 * 60;
break;
case 'C':
offset = -6 * 60;
break;
case 'M':
offset = -7 * 60;
break;
case 'P':
offset = -8 * 60;
break;
default:
/* GMT and others */
return 0;
}
if (i_toupper(str[1]) == 'D')
return offset + 60;
if (i_toupper(str[1]) == 'S')
return offset;
}
return 0;
}
static Rfc822Token next_token(Rfc822TokenizeContext *ctx,
const char **value, size_t *value_len)
{
Rfc822Token token;
token = rfc822_tokenize_next(ctx);
if (token == 'A')
*value = rfc822_tokenize_get_value(ctx, value_len);
return token;
}
static int rfc822_parse_date_tokens(Rfc822TokenizeContext *ctx, time_t *time,
int *timezone_offset)
{
struct tm tm;
Rfc822Token token;
const char *value;
size_t i, len;
/* [weekday_name "," ] dd month_name [yy]yy hh:mi[:ss] timezone */
memset(&tm, 0, sizeof(tm));
/* skip the optional weekday */
token = next_token(ctx, &value, &len);
if (token == 'A' && len == 3) {
token = next_token(ctx, &value, &len);
if (token != ',')
return FALSE;
token = next_token(ctx, &value, &len);
}
/* dd */
if (token != 'A' || len > 2 || !i_isdigit(value[0]))
return FALSE;
tm.tm_mday = value[0]-'0';
if (len == 2) {
if (!i_isdigit(value[1]))
return FALSE;
tm.tm_mday = (tm.tm_mday * 10) + (value[1]-'0');
}
/* month name */
token = next_token(ctx, &value, &len);
if (token != 'A' || len != 3)
return FALSE;
for (i = 0; i < 12; i++) {
if (strncasecmp(month_names[i], value, 3) == 0) {
tm.tm_mon = i;
break;
}
}
if (i == 12)
return FALSE;
/* [yy]yy */
token = next_token(ctx, &value, &len);
if (token != 'A' || (len != 2 && len != 4))
return FALSE;
for (i = 0; i < len; i++) {
if (!i_isdigit(value[i]))
return FALSE;
tm.tm_year = tm.tm_year * 10 + (value[i]-'0');
}
if (len == 2) {
/* two digit year, assume 1970+ */
if (tm.tm_year < 70)
tm.tm_year += 100;
} else {
if (tm.tm_year < 1900)
return FALSE;
tm.tm_year -= 1900;
}
/* hh */
token = next_token(ctx, &value, &len);
if (token != 'A' || len != 2 ||
!i_isdigit(value[0]) || !i_isdigit(value[1]))
return FALSE;
tm.tm_hour = (value[0]-'0') * 10 + (value[1]-'0');
/* :mm */
token = next_token(ctx, &value, &len);
if (token != ':')
return FALSE;
token = next_token(ctx, &value, &len);
if (token != 'A' || len != 2 ||
!i_isdigit(value[0]) || !i_isdigit(value[1]))
return FALSE;
tm.tm_min = (value[0]-'0') * 10 + (value[1]-'0');
/* [:ss] */
token = next_token(ctx, &value, &len);
if (token == ':') {
token = next_token(ctx, &value, &len);
if (token != 'A' || len != 2 ||
!i_isdigit(value[0]) || !i_isdigit(value[1]))
return FALSE;
tm.tm_sec = (value[0]-'0') * 10 + (value[1]-'0');
}
/* timezone */
if (token != 'A')
return FALSE;
*timezone_offset = parse_timezone(value, len);
tm.tm_isdst = -1;
*time = utc_mktime(&tm);
if (*time == (time_t)-1)
return FALSE;
*time -= *timezone_offset;
return TRUE;
}
int rfc822_parse_date(const char *data, time_t *time, int *timezone_offset)
{
Rfc822TokenizeContext *ctx;
int ret;
if (data == NULL || *data == '\0')
return FALSE;
ctx = rfc822_tokenize_init(data, (size_t)-1, NULL, NULL);
ret = rfc822_parse_date_tokens(ctx, time, timezone_offset);
rfc822_tokenize_deinit(ctx);
return ret;
}
const char *rfc822_to_date(time_t time)
{
struct tm *tm;
int offset, negative;
tm = localtime(&time);
offset = utc_offset(tm, time);
if (offset >= 0)
negative = 0;
else {
negative = 1;
offset = -offset;
}
return t_strdup_printf("%s, %02d %s %04d %02d:%02d:%02d %c%02d%02d",
weekday_names[tm->tm_wday],
tm->tm_mday,
month_names[tm->tm_mon],
tm->tm_year+1900,
tm->tm_hour, tm->tm_min, tm->tm_sec,
negative ? '-' : '+', offset / 60, offset % 60);
}