new files to contain functions to parse and format dates and times for

2001-03-04  Damon Chaplin  <damon@ximian.com>

	* e-time-utils.[hc]: new files to contain functions to parse and
	format dates and times for various calendar widgets.

svn path=/trunk/; revision=8546

1 files changed, 292 insertions, 0 deletions

diff --git a/e-util/e-time-utils.c b/e-util/e-time-utils.c
new file mode 100644
index 0000000000..80eb38e2e9
--- /dev/null
+++ b/e-util/e-time-utils.c
@@ -0,0 +1,292 @@
+/* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*- */
+/*
+ * Time utility functions
+ *
+ * Author:
+ *   Damon Chaplin (damon@ximian.com)
+ *
+ * (C) 2001 Ximian, Inc.
+ */
+
+#include <config.h>
+
+/* We need this for strptime. */
+#define _XOPEN_SOURCE 500
+#define __USE_XOPEN
+#include <time.h>
+#include <sys/time.h>
+#undef _XOPEN_SOURCE
+#undef __USE_XOPEN
+
+#include <ctype.h>
+#include <glib.h>
+#include <libgnome/gnome-defs.h>
+#include <libgnome/gnome-i18n.h>
+#include "e-time-utils.h"
+
+static gboolean string_is_empty (const char *value);
+
+
+/*
+ * Parses a string containing a date and a time. The date is expected to be
+ * in a format something like "Wed 3/13/00 14:20:00", though we use gettext
+ * to support the appropriate local formats and we try to accept slightly
+ * different formats, e.g. the weekday can be skipped and we can accept 12-hour
+ * formats with an am/pm string.
+ *
+ * Returns E_TIME_PARSE_OK if it could not be parsed, E_TIME_PARSE_NONE if it
+ * was empty, or E_TIME_PARSE_INVALID if it couldn't be parsed.
+ */
+ETimeParseStatus
+e_time_parse_date_and_time		(const char	*value,
+					 struct tm	*result)
+{
+	struct tm discard_tm, time_tm;
+	struct tm *today_tm;
+	time_t t;
+	const char *pos, *parse_end;
+	char *format[4];
+	gboolean parsed_date = FALSE, parsed_time = FALSE;
+	gint i;
+
+	if (string_is_empty (value))
+		return E_TIME_PARSE_NONE;
+
+	pos = value;
+
+	/* Skip any whitespace. */
+	while (isspace (*pos))
+		pos++;
+
+	/* Skip any weekday name, full or abbreviated. */
+	parse_end = strptime (pos, "%a ", &discard_tm);
+	if (parse_end)
+		pos = parse_end;
+
+	memset (result, 0, sizeof (*result));
+	/* strptime format for a date. */
+	parse_end = strptime (pos, _("%m/%d/%Y"), result);
+	if (parse_end) {
+		pos = parse_end;
+		parsed_date = TRUE;
+	}
+
+	/* Skip any whitespace. */
+	while (isspace (*pos))
+		pos++;
+
+	/* Skip any weekday name, full or abbreviated, again. */
+	parse_end = strptime (pos, "%a ", &discard_tm);
+	if (parse_end)
+		pos = parse_end;
+
+
+	/* strptime format for a time of day, in 12-hour format.
+	   If it is not appropriate in the locale set to an empty string. */
+	format[0] = _("%I:%M:%S %p%n");
+
+	/* strptime format for a time of day, in 24-hour format. */
+	format[1] = _("%H:%M:%S%n");
+
+	/* strptime format for time of day, without seconds, 12-hour format.
+	   If it is is not appropriate in the locale set to an empty string. */
+	format[2] = _("%I:%M %p%n");
+
+	/* strptime format for time of day, without seconds 24-hour format. */
+	format[3] = _("%H:%M%n");
+
+	for (i = 0; i < sizeof (format) / sizeof (format[0]); i++) {
+		memset (&time_tm, 0, sizeof (time_tm));
+		parse_end = strptime (pos, format[i], &time_tm);
+		if (parse_end) {
+			pos = parse_end;
+			parsed_time = TRUE;
+			break;
+		}
+	}
+
+	/* Skip any whitespace. */
+	while (isspace (*pos))
+		pos++;
+
+	/* If we haven't already parsed a date, try again. */
+	if (!parsed_date) {
+		memset (result, 0, sizeof (*result));
+		/* strptime format for a date. */
+		parse_end = strptime (pos, _("%m/%d/%Y"), result);
+		if (parse_end) {
+			pos = parse_end;
+			parsed_date = TRUE;
+		}
+	}
+
+	/* If we don't have a date or a time it must be invalid. */
+	if (!parsed_date && !parsed_time)
+		return E_TIME_PARSE_INVALID;
+
+	if (parsed_date) {
+		/* If a 2-digit year was used we use the current century. */
+		if (result->tm_year < 0) {
+			t = time (NULL);
+			today_tm = localtime (&t);
+
+			/* This should convert it into a value from 0 to 99. */
+			result->tm_year += 1900;
+
+			/* Now add on the century. */
+			result->tm_year += today_tm->tm_year
+				- (today_tm->tm_year % 100);
+		}
+	} else {
+		/* If we didn't get a date we use the current day. */
+		t = time (NULL);
+		today_tm = localtime (&t);
+		result->tm_mday = today_tm->tm_mday;
+		result->tm_mon  = today_tm->tm_mon;
+		result->tm_year = today_tm->tm_year;
+	}
+
+	if (parsed_time) {
+		result->tm_hour = time_tm.tm_hour;
+		result->tm_min = time_tm.tm_min;
+		result->tm_sec = time_tm.tm_sec;
+	} else {
+		result->tm_hour = 0;
+		result->tm_min = 0;
+		result->tm_sec = 0;
+	}
+
+	result->tm_isdst = -1;
+
+	return E_TIME_PARSE_OK;
+}
+
+
+/*
+ * Parses a string containing a time. It is expected to be in a format
+ * something like "14:20:00", though we use gettext to support the appropriate
+ * local formats and we try to accept slightly different formats, e.g. we can
+ * accept 12-hour formats with an am/pm string.
+ *
+ * Returns E_TIME_PARSE_OK if it could not be parsed, E_TIME_PARSE_NONE if it
+ * was empty, or E_TIME_PARSE_INVALID if it couldn't be parsed.
+ */
+ETimeParseStatus
+e_time_parse_time			(const char	*value,
+					 struct tm	*result)
+{
+	const char *pos, *parse_end;
+	char *format[4];
+	gboolean parsed_time = FALSE;
+	gint i;
+
+	if (string_is_empty (value)) {
+		memset (result, 0, sizeof (*result));
+		result->tm_isdst = -1;
+		return E_TIME_PARSE_NONE;
+	}
+
+	pos = value;
+
+	/* Skip any whitespace. */
+	while (isspace (*pos))
+		pos++;
+
+	/* strptime format for a time of day, in 12-hour format.
+	   If it is not appropriate in the locale set to an empty string. */
+	format[0] = _("%I:%M:%S %p%n");
+
+	/* strptime format for a time of day, in 24-hour format. */
+	format[1] = _("%H:%M:%S%n");
+
+	/* strptime format for time of day, without seconds, 12-hour format.
+	   If it is is not appropriate in the locale set to an empty string. */
+	format[2] = _("%I:%M %p%n");
+
+	/* strptime format for time of day, without seconds 24-hour format. */
+	format[3] = _("%H:%M%n");
+
+	for (i = 0; i < sizeof (format) / sizeof (format[0]); i++) {
+		memset (result, 0, sizeof (*result));
+		parse_end = strptime (pos, format[i], result);
+		if (parse_end) {
+			pos = parse_end;
+			parsed_time = TRUE;
+			break;
+		}
+	}
+
+	result->tm_isdst = -1;
+
+	/* If we don't have a date or a time it must be invalid. */
+	if (!parsed_time)
+		return E_TIME_PARSE_INVALID;
+
+	return E_TIME_PARSE_OK;
+}
+
+
+/* Returns whether a string is NULL, empty, or full of whitespace */
+static gboolean
+string_is_empty (const char *value)
+{
+	const char *p;
+	gboolean empty = TRUE;
+
+	if (value) {
+		p = value;
+		while (*p) {
+			if (!isspace (*p)) {
+				empty = FALSE;
+				break;
+			}
+			p++;
+		}
+	}
+	return empty;
+}
+
+
+/* Creates a string representation of a time value and stores it in result.
+   result_size is the size of the result buffer, and should be about 64 to
+   be safe. If show_midnight is FALSE, and the time is midnight, then we just
+   show the date. */
+void
+e_time_format_date_and_time		(struct tm	*date_tm,
+					 gboolean	 use_24_hour_format,
+					 gboolean	 show_midnight,
+					 gboolean	 show_zero_seconds,
+					 char		*result,
+					 int		 result_size)
+{
+	char *format;
+
+	if (!show_midnight && date_tm->tm_hour == 0
+	    && date_tm->tm_min == 0 && date_tm->tm_sec == 0) {
+		/* strftime format of a weekday and a date. */
+		format = _("%a %m/%d/%Y");
+	} else if (use_24_hour_format) {
+		if (!show_zero_seconds && date_tm->tm_sec == 0)
+			/* strftime format of a weekday, a date and a
+			   time, in 24-hour format, without seconds. */
+			format = _("%a %m/%d/%Y %H:%M");
+		else
+			/* strftime format of a weekday, a date and a
+			   time, in 24-hour format. */
+			format = _("%a %m/%d/%Y %H:%M:%S");
+	} else {
+		if (!show_zero_seconds && date_tm->tm_sec == 0)
+			/* strftime format of a weekday, a date and a
+			   time, in 12-hour format, without seconds. */
+			format = _("%a %m/%d/%Y %I:%M %p");
+		else
+			/* strftime format of a weekday, a date and a
+			   time, in 12-hour format. */
+			format = _("%a %m/%d/%Y %I:%M:%S %p");
+	}
+
+	/* strftime returns 0 if the string doesn't fit, and leaves the buffer
+	   undefined, so we set it to the empty string in that case. */
+	if (strftime (result, result_size, format, date_tm) == 0)
+		result[0] = '\0';
+}