Utilities for parsing broken date strings.

2000-06-30  Jeffrey Stedfast  <fejj@helixcode.com>

	* broken-date-parser.[c,h]: Utilities for parsing broken
	date strings.

	* providers/imap/camel-imap-folder.c: fixed some mem leaks

svn path=/trunk/; revision=3840

1 files changed, 315 insertions, 0 deletions

diff --git a/camel/broken-date-parser.c b/camel/broken-date-parser.c
new file mode 100644
index 0000000000..544dc04e28
--- /dev/null
+++ 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                                                     *
+ *****************************************************************************/