path: root/e-util/e-time-utils.c

/* -*- 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 <string.h>
#include <ctype.h>
#include <glib.h>
#include <libgnome/gnome-defs.h>
#include <libgnome/gnome-i18n.h>
#include "e-time-utils.h"


/* 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;
}


/*
 * 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 time_tm;
    struct tm *today_tm;
    time_t t;
    const char *pos, *parse_end;
    char *format[5];
    gboolean parsed_date = FALSE, 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 everything up to the first digit. */
    while (!isdigit (*pos))
        pos++;

    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;
    }

    /* FIXME: Skip everything up to the first digit. I hope the am/pm flag
       never gets entered first - it does in Japanese, so fix this. */
    while (!isdigit (*pos))
        pos++;


    /* strptime format for a time of day, in 12-hour format. */
    format[0] = _("%I:%M:%S %p");

    /* strptime format for a time of day, in 24-hour format. */
    format[1] = _("%H:%M:%S");

    /* strptime format for time of day, without seconds, 12-hour format. */
    format[2] = _("%I:%M %p");

    /* strptime format for hour and AM/PM */
    format[3] = _("%I %p");

    /* strptime format for time of day, without seconds 24-hour format. */
    format[4] = _("%H:%M");

    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;
}

/* Takes a number of format strings for strptime() and attempts to parse a
 * string with them.
 */
static ETimeParseStatus
parse_with_strptime (const char *value, struct tm *result, const char **formats, int n_formats)
{
    const char *pos, *parse_end;
    gboolean parsed;
    int i;

    if (string_is_empty (value)) {
        memset (result, 0, sizeof (*result));
        result->tm_isdst = -1;
        return E_TIME_PARSE_NONE;
    }

    pos = value;

    /* Skip whitespace */
    while (isspace (*pos))
        pos++;

    /* Try each of the formats in turn */

    for (i = 0; i < n_formats; i++) {
        memset (result, 0, sizeof (*result));
        parse_end = strptime (pos, formats[i], result);
        if (parse_end) {
            pos = parse_end;
            parsed = TRUE;
            break;
        }
    }

    result->tm_isdst = -1;

    /* If we could not parse it it must be invalid. */
    if (!parsed)
        return E_TIME_PARSE_INVALID;

    return E_TIME_PARSE_OK;
}


/**
 * e_time_parse_date:
 * @value: A date string.
 * @result: Return value for the parsed date.
 * 
 * Takes in a date string entered by the user and tries to convert it to
 * a struct tm.
 * 
 * Return value: Result code indicating whether the @value was an empty
 * string, a valid date, or an invalid date.
 **/
ETimeParseStatus
e_time_parse_date (const char *value, struct tm *result)
{
    const char *format[4];

    g_return_val_if_fail (value != NULL, E_TIME_PARSE_INVALID);
    g_return_val_if_fail (result != NULL, E_TIME_PARSE_INVALID);

    /* This is the preferred date format for the locale. */
    format[0] = _("%m/%d/%Y");

    /* This is the second-choice date format for the locale, which we use
       if previous attempts to parse the date string failed. */
    format[1] = _("%d/%m/%Y");

    /* This is the third-choice date format for the locale, which we use
       if previous attempts to parse the date string failed. */
    format[2] = _("%Y/%m/%d");

    /* This is the final-choice date format for the locale, which we use
       if previous attempts to parse the date string failed. */
    format[3] = _("%x"); /* catch-all give-up strptime()-sucks format */

    return parse_with_strptime (value, result, format, sizeof (format) / sizeof (format[0]));
}


/*
 * 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 *format[5];

    /* 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");

    /* strptime format for a time of day, in 24-hour format. */
    format[1] = _("%H:%M:%S");

    /* 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");

    /* strptime format for hour and AM/PM */
    format[3] = _("%I %p");

    /* strptime format for time of day, without seconds 24-hour format. */
    format[4] = _("%H:%M");

    return parse_with_strptime (value, result, format, sizeof (format) / sizeof (format[0]));
}


/* Creates a string representation of a time value and stores it in buffer.
   buffer_size should be about 64 to be safe. If show_midnight is FALSE, and
   the time is midnight, then we just show the date. If show_zero_seconds
   is FALSE, then if the time has zero seconds only the hour and minute are
   shown. */
void
e_time_format_date_and_time     (struct tm  *date_tm,
                     gboolean    use_24_hour_format,
                     gboolean    show_midnight,
                     gboolean    show_zero_seconds,
                     char       *buffer,
                     int         buffer_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 (buffer, buffer_size, format, date_tm) == 0)
        buffer[0] = '\0';
}


/* Creates a string representation of a time value and stores it in buffer.
   buffer_size should be about 64 to be safe. */
void
e_time_format_time          (struct tm  *date_tm,
                     gboolean    use_24_hour_format,
                     gboolean    show_zero_seconds,
                     char       *buffer,
                     int         buffer_size)
{
    char *format;

    if (use_24_hour_format) {
        if (!show_zero_seconds && date_tm->tm_sec == 0)
            /* strftime format of a time in 24-hour format,
               without seconds. */
            format = _("%H:%M");
        else
            /* strftime format of a time in 24-hour format. */
            format = _("%H:%M:%S");
    } else {
        if (!show_zero_seconds && date_tm->tm_sec == 0)
            /* strftime format of a time in 12-hour format,
               without seconds. */
            format = _("%I:%M %p");
        else
            /* strftime format of a time in 12-hour format. */
            format = _("%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 (buffer, buffer_size, format, date_tm) == 0)
        buffer[0] = '\0';
}