--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/lib-mail/rfc822-date.c	Fri Aug 09 12:15:38 2002 +0300
@@ -0,0 +1,226 @@
+/* Copyright (C) 2002 Timo Sirainen */
+
+#include "lib.h"
+#include "gmtoff.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, unsigned int len)
+{
+	int offset;
+	char chr;
+
+	if (len == 5 && (*str == '+' || *str == '-')) {
+		/* numeric offset */
+		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 const Rfc822Token *next_token(const Rfc822Token **tokens)
+{
+	const Rfc822Token *ret;
+
+	if ((*tokens)->token == 0)
+		return NULL;
+
+	ret = *tokens;
+	(*tokens)++;
+	return ret;
+}
+
+int rfc822_parse_date(const char *str, time_t *time)
+{
+	struct tm tm;
+	const Rfc822Token *tokens, *tok;
+	unsigned int i;
+	int zone_offset;
+
+	if (str == NULL || *str == '\0')
+		return FALSE;
+
+	/* [weekday_name "," ] dd month_name [yy]yy hh:mi[:ss] timezone
+
+	   don't waste time checking it too properly, if there's errors we
+	   either pick them up at mktime() or have an invalid timestamp,
+	   which would happen anyway.
+
+	   we support comments here even while no-one ever uses them */
+
+	tokens = rfc822_tokenize(str, NULL, NULL, NULL);
+
+	memset(&tm, 0, sizeof(tm));
+
+	/* skip the optional weekday */
+	tok = next_token(&tokens);
+	if (tok != NULL && tok->token == 'A' && tok->len == 3) {
+		tok = next_token(&tokens);
+		if (tok == NULL || tok->token != ',')
+			return FALSE;
+
+		tok = next_token(&tokens);
+	}
+
+	/* dd */
+	if (tok == NULL || tok->token != 'A' || tok->len != 2)
+		return FALSE;
+	tm.tm_mday = (tok->ptr[0]-'0') * 10 + tok->ptr[1]-'0';
+
+	/* month name */
+	tok = next_token(&tokens);
+	if (tok == NULL || tok->token != 'A' || tok->len != 3)
+		return FALSE;
+
+	for (i = 0; i < 12; i++) {
+		if (strncasecmp(month_names[i], tok->ptr, 3) == 0) {
+			tm.tm_mon = i;
+			break;
+		}
+	}
+	if (i == 12)
+		return FALSE;
+
+	/* [yy]yy */
+	tok = next_token(&tokens);
+	if (tok == NULL || tok->token != 'A')
+		return FALSE;
+
+	for (i = 0; i < tok->len; i++)
+		tm.tm_year = tm.tm_year * 10 + tok->ptr[i]-'0';
+
+	if (tok->len == 2) {
+		/* two digit year, assume 1970+ */
+		if (tm.tm_year < 70)
+			tm.tm_year += 100;
+	} else if (tok->len != 4) {
+		/* y10k bug here */
+		tm.tm_year -= 1900;
+		return FALSE;
+	}
+
+	/* hh */
+	tok = next_token(&tokens);
+	if (tok == NULL || tok->token != 'A' || tok->len != 2)
+		return FALSE;
+	tm.tm_hour = (tok->ptr[0]-'0') * 10 + tok->ptr[1]-'0';
+
+	/* :mm */
+	tok = next_token(&tokens);
+	if (tok == NULL || tok->token != ':')
+		return FALSE;
+	tok = next_token(&tokens);
+	if (tok == NULL || (tok->token != 'A' && tok->len != 2))
+		return FALSE;
+	tm.tm_min = (tok->ptr[0]-'0') * 10 + tok->ptr[1]-'0';
+
+	/* [:ss] */
+	tok = next_token(&tokens);
+	if (tok != NULL && tok->token == ':') {
+		tok = next_token(&tokens);
+		if (tok == NULL || (tok->token != 'A' && tok->len != 2))
+			return FALSE;
+		tm.tm_sec = (tok->ptr[0]-'0') * 10 + tok->ptr[1]-'0';
+	}
+
+	/* timezone */
+	if (tok == NULL || tok->token != 'A')
+		return FALSE;
+
+	zone_offset = parse_timezone(tok->ptr, tok->len);
+
+	tm.tm_isdst = -1;
+	*time = mktime(&tm);
+	if (*time < 0)
+		return FALSE;
+
+	*time -= zone_offset * 60;
+	return TRUE;
+}
+
+const char *rfc822_to_date(time_t time)
+{
+	struct tm *tm;
+	int offset, negative;
+
+	tm = localtime(&time);
+	offset = gmtoff(tm, time);
+	if (offset >= 0)
+		negative = 0;
+	else {
+		negative = 1;
+		offset = -offset;
+	}
+	offset /= 60;
+
+	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);
+}