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-rw-r--r--camel/broken-date-parser.c315
1 files changed, 315 insertions, 0 deletions
diff --git a/camel/broken-date-parser.c b/camel/broken-date-parser.c
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+/* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*- */
+/*
+ * Authors: Jeffrey Stedfast <fejj@helixcode.com>
+ *
+ * Copyright 2000 Helix Code, Inc. (www.helixcode.com)
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Street #330, Boston, MA 02111-1307, USA.
+ *
+ */
+
+#include "broken-date-parser.h"
+
+/* prototypes for functions dealing with broken date formats */
+static GList *datetok (const gchar *date);
+static gint get_days_in_month (gint mon, gint year);
+static gint get_weekday (gchar *str);
+static gint get_month (gchar *str);
+
+static char *tz_months [] = {
+ "Jan", "Feb", "Mar", "Apr", "May", "Jun",
+ "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"
+};
+
+/*****************************************************************************
+ * The following functions are here in the case of badly broken date formats *
+ * *
+ * -- fejj@helixcode.com *
+ *****************************************************************************/
+
+typedef struct {
+ gchar dow[6]; /* day of week (should only need 4 chars) */
+ gint day;
+ gint mon; /* 1->12 or 0 if invalid */
+ gint year;
+ gint hour;
+ gint min;
+ gint sec;
+ gchar zone[6]; /* time zone */
+} date_t;
+
+static
+GList *datetok (const gchar *date)
+{
+ GList *tokens = NULL;
+ gchar *token, *start, *end;
+
+ start = (gchar *) date;
+ while (*start) {
+ /* find the end of this token */
+ for (end = start; *end && *end != ' '; end++);
+
+ token = g_strndup (start, (end - start));
+
+ if (token && *token)
+ tokens = g_list_append (tokens, token);
+ else
+ g_free (token);
+
+ if (*end)
+ start = end + 1;
+ else
+ break;
+ }
+
+ return tokens;
+}
+
+static gint
+get_days_in_month (gint mon, gint year)
+{
+ switch (mon) {
+ case 1: case 3: case 5: case 7: case 8: case 10: case 12:
+ return 31;
+ case 4: case 6: case 9: case 11:
+ return 30;
+ case 2:
+ if ((year % 4 == 0 && year % 100 != 0) || year % 400 == 0)
+ return 29;
+ return 28;
+ default:
+ return 30;
+ }
+}
+
+static gint
+get_weekday (gchar *str)
+{
+ g_return_val_if_fail ((str != NULL), 0);
+
+ if (strncmp (str, "Mon", 3) == 0) {
+ return 1;
+ } else if (strncmp (str, "Tue", 3) == 0) {
+ return 2;
+ } else if (strncmp (str, "Wed", 3) == 0) {
+ return 3;
+ } else if (strncmp (str, "Thu", 3) == 0) {
+ return 4;
+ } else if (strncmp (str, "Fri", 3) == 0) {
+ return 5;
+ } else if (strncmp (str, "Sat", 3) == 0) {
+ return 6;
+ } else if (strncmp (str, "Sun", 3) == 0) {
+ return 7;
+ }
+
+ return 0; /* unknown week day */
+}
+
+static gint
+get_month (gchar *str)
+{
+ g_return_val_if_fail (str != NULL, 0);
+
+ if (strncmp (str, "Jan", 3) == 0) {
+ return 1;
+ } else if (strncmp (str, "Feb", 3) == 0) {
+ return 2;
+ } else if (strncmp (str, "Mar", 3) == 0) {
+ return 3;
+ } else if (strncmp (str, "Apr", 3) == 0) {
+ return 4;
+ } else if (strncmp (str, "May", 3) == 0) {
+ return 5;
+ } else if (strncmp (str, "Jun", 3) == 0) {
+ return 6;
+ } else if (strncmp (str, "Jul", 3) == 0) {
+ return 7;
+ } else if (strncmp (str, "Aug", 3) == 0) {
+ return 8;
+ } else if (strncmp (str, "Sep", 3) == 0) {
+ return 9;
+ } else if (strncmp (str, "Oct", 3) == 0) {
+ return 10;
+ } else if (strncmp (str, "Nov", 3) == 0) {
+ return 11;
+ } else if (strncmp (str, "Dec", 3) == 0) {
+ return 12;
+ }
+
+ return 0; /* unknown month */
+}
+
+gchar *
+parse_broken_date (const gchar *datestr)
+{
+ GList *tokens;
+ date_t date;
+ gchar *token, *ptr, *newdatestr;
+ guint len, i, retval;
+ gdouble tz = 0.0;
+
+ memset ((void*)&date, 0, sizeof (date_t));
+ g_return_val_if_fail (datestr != NULL, NULL);
+
+ tokens = datetok (datestr);
+ len = g_list_length (tokens);
+ for (i = 0; i < len; i++) {
+ token = g_list_nth_data (tokens, i);
+
+ if ((retval = get_weekday (token))) {
+ strncpy (date.dow, datestr, 4);
+ } else if ((retval = get_month (token))) {
+ date.mon = retval;
+ } else if (strlen (token) <= 2) {
+ /* this could be a 1 or 2 digit day of the month */
+ for (retval = 1, ptr = token; *ptr; ptr++)
+ if (*ptr < '0' || *ptr > '9')
+ retval = 0;
+
+ if (retval && atoi (token) <= 31 && !date.day) /* probably should find a better way */
+ date.day = atoi (token);
+ else /* fubar'd client using a 2-digit year */
+ date.year = atoi (token) < 69 ? 2000 + atoi (token) : 1900 + atoi (token);
+ } else if (strlen (token) == 4) {
+ /* this could be the year... */
+ for (retval = 1, ptr = token; *ptr; ptr++)
+ if (*ptr < '0' || *ptr > '9')
+ retval = 0;
+
+ if (retval)
+ date.year = atoi (token);
+ } else if (strchr (token, ':')) {
+ /* this must be the time: hh:mm:ss */
+ sscanf (token, "%d:%d:%d", &date.hour, &date.min, &date.sec);
+ } else if (*token == '-' || *token == '+') {
+ tz = atoi (token) / 100.0;
+ }
+ }
+
+ g_list_free (tokens);
+
+ /* adjust times based on time zones */
+
+ if (tz != 0) {
+ /* check for time-zone shift */
+ if (tz > 0) {
+ /* correct for positive hours off of UCT */
+ date.hour -= (tz / 100);
+ tz = (gint)tz % 100;
+
+ if (tz > 0) /* correct for positive minutes off of UCT */
+ date.min -= (gint)(((gdouble) tz / 100.0) * 60.0);
+ } else {
+ if (tz < 0) {
+ /* correct for negative hours off of UCT */
+ tz = -tz;
+ date.hour += (tz / 100);
+ tz = -((gint)tz % 100);
+
+ if (tz < 0)
+ date.min -= (gint)(((gdouble) tz / 100.0) * 60.0);
+ }
+ }
+
+ /* adjust seconds to proper range */
+ if (date.sec > 59) {
+ date.min += (date.sec / 60);
+ date.sec = (date.sec % 60);
+ }
+
+ /* adjust minutes to proper range */
+ if (date.min > 59) {
+ date.hour += (date.min / 60);
+ date.min = (date.min % 60);
+ } else {
+ if (date.min < 0) {
+ date.min = -date.min;
+ date.hour -= (date.min / 60) - 1;
+ date.min = 60 - (date.min % 60);
+ }
+ }
+
+ /* adjust hours to the proper randge */
+ if (date.hour > 23) {
+ date.day += (date.hour / 24);
+ date.hour -= (date.hour % 24);
+ } else {
+ if (date.hour < 0) {
+ date.hour = -date.hour;
+ date.day -= (date.hour / 24) - 1;
+ date.hour = 24 - (date.hour % 60);
+ }
+ }
+
+ /* adjust days to the proper range */
+ while (date.day > get_days_in_month (date.mon, date.year)) {
+ date.day -= get_days_in_month (date.mon, date.year);
+ date.mon++;
+ if (date.mon > 12) {
+ date.year += (date.mon / 12);
+ date.mon = (date.mon % 12);
+ if (date.mon == 0) {
+ /* month sanity check */
+ date.mon = 12;
+ date.year -= 1;
+ }
+ }
+ }
+
+ while (date.day < 1) {
+ date.day += get_days_in_month (date.mon, date.year);
+ date.mon--;
+ if (date.mon < 1) {
+ date.mon = -date.mon;
+ date.year -= (date.mon / 12) - 1;
+ date.mon = 12 - (date.mon % 12);
+ }
+ }
+
+ /* adjust months to the proper range */
+ if (date.mon > 12) {
+ date.year += (date.mon / 12);
+ date.mon = (date.mon % 12);
+ if (date.mon == 0) {
+ /* month sanity check */
+ date.mon = 12;
+ date.year -= 1;
+ }
+ } else {
+ if (date.mon < 1) {
+ date.mon = -date.mon;
+ date.year -= (date.mon / 12) - 1;
+ date.mon = 12 - (date.mon % 12);
+ }
+ }
+ }
+
+ /* now lets print this date into a string with the correct format */
+ newdatestr = g_strdup_printf ("%s, %d %s %d %s%d:%s%d:%s%d -0000",
+ date.dow, date.day, tz_months[date.mon-1],
+ date.year,
+ date.hour > 10 ? "" : "0", date.hour,
+ date.min > 10 ? "" : "0", date.min,
+ date.sec > 10 ? "" : "0", date.sec);
+
+ return newdatestr;
+}
+
+/*****************************************************************************
+ * This ends the code for the broken date parser... *
+ * *
+ * -- fejj@helixcode.com *
+ *****************************************************************************/
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