glibc/time/getdate.c

257 lines
6.6 KiB
C

/* Convert a string representation of time to a time value.
Copyright (C) 1997, 1998, 1999, 2000 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Mark Kettenis <kettenis@phys.uva.nl>, 1997.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public License as
published by the Free Software Foundation; either version 2 of the
License, or (at your option) any later version.
The GNU C Library 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
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB. If not,
write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <sys/stat.h>
#define TM_YEAR_BASE 1900
/* Prototypes for local functions. */
static int first_wday (int year, int mon, int wday);
static int check_mday (int year, int mon, int mday);
/* Set to one of the following values to indicate an error.
1 the DATEMSK environment variable is null or undefined,
2 the template file cannot be opened for reading,
3 failed to get file status information,
4 the template file is not a regular file,
5 an error is encountered while reading the template file,
6 memory allication failed (not enough memory available),
7 there is no line in the template that matches the input,
8 invalid input specification Example: February 31 or a time is
specified that can not be represented in a time_t (representing
the time in seconds since 00:00:00 UTC, January 1, 1970) */
int getdate_err;
/* Returns the first weekday WDAY of month MON in the year YEAR. */
static int
first_wday (int year, int mon, int wday)
{
struct tm tm;
if (wday == INT_MIN)
return 1;
memset (&tm, 0, sizeof (struct tm));
tm.tm_year = year;
tm.tm_mon = mon;
tm.tm_mday = 1;
mktime (&tm);
return (1 + (wday - tm.tm_wday + 7) % 7);
}
/* Returns 1 if MDAY is a valid day of the month in month MON of year
YEAR, and 0 if it is not. */
static int
check_mday (int year, int mon, int mday)
{
switch (mon)
{
case 0:
case 2:
case 4:
case 6:
case 7:
case 9:
case 11:
if (mday >= 1 && mday <= 31)
return 1;
break;
case 3:
case 5:
case 8:
case 10:
if (mday >= 1 && mday <= 30)
return 1;
break;
case 1:
if (mday >= 1 && mday <= (__isleap (year) ? 29 : 28))
return 1;
break;
}
return 0;
}
int
__getdate_r (const char *string, struct tm *tp)
{
FILE *fp;
char *line;
size_t len;
char *datemsk;
char *result = NULL;
time_t timer;
struct tm tm;
struct stat st;
int mday_ok = 0;
datemsk = getenv ("DATEMSK");
if (datemsk == NULL || *datemsk == '\0')
return 1;
if (stat (datemsk, &st) < 0)
return 3;
if (!S_ISREG (st.st_mode))
return 4;
/* Open the template file. */
fp = fopen (datemsk, "r");
if (fp == NULL)
return 2;
line = NULL;
len = 0;
do
{
ssize_t n;
n = __getline (&line, &len, fp);
if (n < 0)
break;
if (line[n - 1] == '\n')
line[n - 1] = '\0';
/* Do the conversion. */
tp->tm_year = tp->tm_mon = tp->tm_mday = tp->tm_wday = INT_MIN;
tp->tm_hour = tp->tm_sec = tp->tm_min = INT_MIN;
result = strptime (string, line, tp);
if (result && *result == '\0')
break;
}
while (!feof_unlocked (fp));
/* Free the buffer. */
free (line);
/* Check for errors. */
if (ferror_unlocked (fp))
{
fclose (fp);
return 5;
}
/* Close template file. */
fclose (fp);
if (result == NULL || *result != '\0')
return 7;
/* Get current time. */
time (&timer);
__localtime_r (&timer, &tm);
/* If only the weekday is given, today is assumed if the given day
is equal to the current day and next week if it is less. */
if (tp->tm_wday >= 0 && tp->tm_wday <= 6 && tp->tm_year == INT_MIN
&& tp->tm_mon == INT_MIN && tp->tm_mday == INT_MIN)
{
tp->tm_year = tm.tm_year;
tp->tm_mon = tm.tm_mon;
tp->tm_mday = tm.tm_mday + (tp->tm_wday - tm.tm_wday + 7) % 7;
mday_ok = 1;
}
/* If only the month is given, the current month is assumed if the
given month is equal to the current month and next year if it is
less and no year is given (the first day of month is assumed if
no day is given. */
if (tp->tm_mon >= 0 && tp->tm_mon <= 11 && tp->tm_mday == INT_MIN)
{
if (tp->tm_year == INT_MIN)
tp->tm_year = tm.tm_year + (((tp->tm_mon - tm.tm_mon) < 0) ? 1 : 0);
tp->tm_mday = first_wday (tp->tm_year, tp->tm_mon, tp->tm_wday);
mday_ok = 1;
}
/* If no hour, minute and second are given the current hour, minute
and second are assumed. */
if (tp->tm_hour == INT_MIN && tp->tm_min == INT_MIN && tp->tm_sec == INT_MIN)
{
tp->tm_hour = tm.tm_hour;
tp->tm_min = tm.tm_min;
tp->tm_sec = tm.tm_sec;
}
/* If no date is given, today is assumed if the given hour is
greater than the current hour and tomorrow is assumed if
it is less. */
if (tp->tm_hour >= 0 && tp->tm_hour <= 23
&& tp->tm_year == INT_MIN && tp->tm_mon == INT_MIN
&& tp->tm_mday == INT_MIN && tp->tm_wday == INT_MIN)
{
tp->tm_year = tm.tm_year;
tp->tm_mon = tm.tm_mon;
tp->tm_mday = tm.tm_mday + ((tp->tm_hour - tm.tm_hour) < 0 ? 1 : 0);
mday_ok = 1;
}
/* Fill in the gaps. */
if (tp->tm_year == INT_MIN)
tp->tm_year = tm.tm_year;
if (tp->tm_hour == INT_MIN)
tp->tm_hour = 0;
if (tp->tm_min == INT_MIN)
tp->tm_min = 0;
if (tp->tm_sec == INT_MIN)
tp->tm_sec = 0;
/* Check if the day of month is within range, and if the time can be
represented in a time_t. We make use of the fact that the mktime
call normalizes the struct tm. */
if ((!mday_ok && !check_mday (TM_YEAR_BASE + tp->tm_year, tp->tm_mon,
tp->tm_mday))
|| mktime (tp) == (time_t) -1)
return 8;
return 0;
}
#ifdef weak_alias
weak_alias (__getdate_r, getdate_r)
#endif
struct tm *
getdate (const char *string)
{
/* Buffer returned by getdate. */
static struct tm tmbuf;
int errval = __getdate_r (string, &tmbuf);
if (errval != 0)
{
getdate_err = errval;
return NULL;
}
return &tmbuf;
}