/* Copyright (C) 1991-2018 Free Software Foundation, Inc.

   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or

   modify it under the terms of the GNU Lesser General Public

   License as published by the Free Software Foundation; either

   version 2.1 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

   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public

   License along with the GNU C Library; if not, see

   <http://www.gnu.org/licenses/>.  */

#include "../locale/localeinfo.h"

#include <errno.h>

#include <limits.h>

#include <stdio.h>

#include <time.h>

/* This is defined in locale/C-time.c in the GNU libc.  */

extern const struct __locale_data _nl_C_LC_TIME attribute_hidden;

#define ab_day_name(DAY) (_nl_C_LC_TIME.values[_NL_ITEM_INDEX (ABDAY_1)+(DAY)].string)

#define ab_month_name(MON) (_nl_C_LC_TIME.values[_NL_ITEM_INDEX (ABMON_1)+(MON)].string)

static const char format[] = "%.3s %.3s%3d %.2d:%.2d:%.2d %d\n";

static char result[		 3+1+ 3+1+20+1+20+1+20+1+20+1+20+1 + 1];

static char *

asctime_internal (const struct tm *tp, char *buf, size_t buflen)

{

  if (tp == NULL)

    {

      __set_errno (EINVAL);

      return NULL;

    }

  /* We limit the size of the year which can be printed.  Using the %d

     format specifier used the addition of 1900 would overflow the

     number and a negative vaue is printed.  For some architectures we

     could in theory use %ld or an evern larger integer format but

     this would mean the output needs more space.  This would not be a

     problem if the 'asctime_r' interface would be defined sanely and

     a buffer size would be passed.  */

  if (__glibc_unlikely (tp->tm_year > INT_MAX - 1900))

    {

    eoverflow:

      __set_errno (EOVERFLOW);

      return NULL;

    }

  int n = __snprintf (buf, buflen, format,

		      (tp->tm_wday < 0 || tp->tm_wday >= 7 ?

		       "???" : ab_day_name (tp->tm_wday)),

		      (tp->tm_mon < 0 || tp->tm_mon >= 12 ?

		       "???" : ab_month_name (tp->tm_mon)),

		      tp->tm_mday, tp->tm_hour, tp->tm_min,

		      tp->tm_sec, 1900 + tp->tm_year);

  if (n < 0)

    return NULL;

  if (n >= buflen)

    goto eoverflow;

  return buf;

}

/* Like asctime, but write result to the user supplied buffer.  The

   buffer is only guaranteed to be 26 bytes in length.  */

char *

__asctime_r (const struct tm *tp, char *buf)

{

  return asctime_internal (tp, buf, 26);

}

weak_alias (__asctime_r, asctime_r)

/* Returns a string of the form "Day Mon dd hh:mm:ss yyyy\n"

   which is the representation of TP in that form.  */

char *

asctime (const struct tm *tp)

{

  return asctime_internal (tp, result, sizeof (result));

}

libc_hidden_def (asctime)