# serial 28

dnl Copyright (C) 2002-2003, 2005-2007, 2009-2017 Free Software Foundation,

dnl Inc.

dnl This file is free software; the Free Software Foundation

dnl gives unlimited permission to copy and/or distribute it,

dnl with or without modifications, as long as this notice is preserved.

dnl From Jim Meyering.

AC_DEFUN([gl_TIME_T_IS_SIGNED],

[

  AC_CACHE_CHECK([whether time_t is signed],

    [gl_cv_time_t_is_signed],

    [AC_COMPILE_IFELSE(

       [AC_LANG_PROGRAM([[#include <time.h>

                          char time_t_signed[(time_t) -1 < 0 ? 1 : -1];]])],

       [gl_cv_time_t_is_signed=yes],

       [gl_cv_time_t_is_signed=no])])

  if test $gl_cv_time_t_is_signed = yes; then

    AC_DEFINE([TIME_T_IS_SIGNED], [1], [Define to 1 if time_t is signed.])

  fi

])

dnl Test whether mktime works. Set gl_cv_func_working_mktime.

AC_DEFUN([gl_FUNC_MKTIME_WORKS],

[

  AC_REQUIRE([gl_TIME_T_IS_SIGNED])

  dnl We don't use AC_FUNC_MKTIME any more, because it is no longer maintained

  dnl in Autoconf and because it invokes AC_LIBOBJ.

  AC_CHECK_HEADERS_ONCE([unistd.h])

  AC_CHECK_DECLS_ONCE([alarm])

  AC_CHECK_FUNCS_ONCE([tzset])

  AC_REQUIRE([gl_MULTIARCH])

  if test $APPLE_UNIVERSAL_BUILD = 1; then

    # A universal build on Apple Mac OS X platforms.

    # The test result would be 'yes' in 32-bit mode and 'no' in 64-bit mode.

    # But we need a configuration result that is valid in both modes.

    gl_cv_func_working_mktime=no

  fi

  AC_CACHE_CHECK([for working mktime], [gl_cv_func_working_mktime],

    [AC_RUN_IFELSE(

       [AC_LANG_SOURCE(

[[/* Test program from Paul Eggert and Tony Leneis.  */

#include <limits.h>

#include <stdlib.h>

#include <time.h>

#ifdef HAVE_UNISTD_H

# include <unistd.h>

#endif

#if HAVE_DECL_ALARM

# include <signal.h>

#endif

/* Work around redefinition to rpl_putenv by other config tests.  */

#undef putenv

static time_t time_t_max;

static time_t time_t_min;

/* Values we'll use to set the TZ environment variable.  */

static char *tz_strings[] = {

  (char *) 0, "TZ=GMT0", "TZ=JST-9",

  "TZ=EST+3EDT+2,M10.1.0/00:00:00,M2.3.0/00:00:00"

};

#define N_STRINGS (sizeof (tz_strings) / sizeof (tz_strings[0]))

/* Return 0 if mktime fails to convert a date in the spring-forward gap.

   Based on a problem report from Andreas Jaeger.  */

static int

spring_forward_gap ()

{

  /* glibc (up to about 1998-10-07) failed this test. */

  struct tm tm;

  /* Use the portable POSIX.1 specification "TZ=PST8PDT,M4.1.0,M10.5.0"

     instead of "TZ=America/Vancouver" in order to detect the bug even

     on systems that don't support the Olson extension, or don't have the

     full zoneinfo tables installed.  */

  putenv ("TZ=PST8PDT,M4.1.0,M10.5.0");

  tm.tm_year = 98;

  tm.tm_mon = 3;

  tm.tm_mday = 5;

  tm.tm_hour = 2;

  tm.tm_min = 0;

  tm.tm_sec = 0;

  tm.tm_isdst = -1;

  return mktime (&tm) != (time_t) -1;

}

static int

mktime_test1 (time_t now)

{

  struct tm *lt;

  return ! (lt = localtime (&now)) || mktime (lt) == now;

}

static int

mktime_test (time_t now)

{

  return (mktime_test1 (now)

          && mktime_test1 ((time_t) (time_t_max - now))

          && mktime_test1 ((time_t) (time_t_min + now)));

}

static int

irix_6_4_bug ()

{

  /* Based on code from Ariel Faigon.  */

  struct tm tm;

  tm.tm_year = 96;

  tm.tm_mon = 3;

  tm.tm_mday = 0;

  tm.tm_hour = 0;

  tm.tm_min = 0;

  tm.tm_sec = 0;

  tm.tm_isdst = -1;

  mktime (&tm;;

  return tm.tm_mon == 2 && tm.tm_mday == 31;

}

static int

bigtime_test (int j)

{

  struct tm tm;

  time_t now;

  tm.tm_year = tm.tm_mon = tm.tm_mday = tm.tm_hour = tm.tm_min = tm.tm_sec = j;

  now = mktime (&tm;;

  if (now != (time_t) -1)

    {

      struct tm *lt = localtime (&now;;

      if (! (lt

             && lt->tm_year == tm.tm_year

             && lt->tm_mon == tm.tm_mon

             && lt->tm_mday == tm.tm_mday

             && lt->tm_hour == tm.tm_hour

             && lt->tm_min == tm.tm_min

             && lt->tm_sec == tm.tm_sec

             && lt->tm_yday == tm.tm_yday

             && lt->tm_wday == tm.tm_wday

             && ((lt->tm_isdst < 0 ? -1 : 0 < lt->tm_isdst)

                  == (tm.tm_isdst < 0 ? -1 : 0 < tm.tm_isdst))))

        return 0;

    }

  return 1;

}

static int

year_2050_test ()

{

  /* The correct answer for 2050-02-01 00:00:00 in Pacific time,

     ignoring leap seconds.  */

  unsigned long int answer = 2527315200UL;

  struct tm tm;

  time_t t;

  tm.tm_year = 2050 - 1900;

  tm.tm_mon = 2 - 1;

  tm.tm_mday = 1;

  tm.tm_hour = tm.tm_min = tm.tm_sec = 0;

  tm.tm_isdst = -1;

  /* Use the portable POSIX.1 specification "TZ=PST8PDT,M4.1.0,M10.5.0"

     instead of "TZ=America/Vancouver" in order to detect the bug even

     on systems that don't support the Olson extension, or don't have the

     full zoneinfo tables installed.  */

  putenv ("TZ=PST8PDT,M4.1.0,M10.5.0");

  t = mktime (&tm;;

  /* Check that the result is either a failure, or close enough

     to the correct answer that we can assume the discrepancy is

     due to leap seconds.  */

  return (t == (time_t) -1

          || (0 < t && answer - 120 <= t && t <= answer + 120));

}

int

main ()

{

  int result = 0;

  time_t t, delta;

  int i, j;

  int time_t_signed_magnitude = (time_t) ~ (time_t) 0 < (time_t) -1;

#if HAVE_DECL_ALARM

  /* This test makes some buggy mktime implementations loop.

     Give up after 60 seconds; a mktime slower than that

     isn't worth using anyway.  */

  signal (SIGALRM, SIG_DFL);

  alarm (60);

#endif

  time_t_max = (! TIME_T_IS_SIGNED

                ? (time_t) -1

                : ((((time_t) 1 << (sizeof (time_t) * CHAR_BIT - 2)) - 1)

                   * 2 + 1));

  time_t_min = (! TIME_T_IS_SIGNED

                ? (time_t) 0

                : time_t_signed_magnitude

                ? ~ (time_t) 0

                : ~ time_t_max);

  delta = time_t_max / 997; /* a suitable prime number */

  for (i = 0; i < N_STRINGS; i++)

    {

      if (tz_strings[i])

        putenv (tz_strings[i]);

      for (t = 0; t <= time_t_max - delta && (result & 1) == 0; t += delta)

        if (! mktime_test (t))

          result |= 1;

      if ((result & 2) == 0

          && ! (mktime_test ((time_t) 1)

                && mktime_test ((time_t) (60 * 60))

                && mktime_test ((time_t) (60 * 60 * 24))))

        result |= 2;

      for (j = 1; (result & 4) == 0; j <<= 1)

        {

          if (! bigtime_test (j))

            result |= 4;

          if (INT_MAX / 2 < j)

            break;

        }

      if ((result & 8) == 0 && ! bigtime_test (INT_MAX))

        result |= 8;

    }

  if (! irix_6_4_bug ())

    result |= 16;

  if (! spring_forward_gap ())

    result |= 32;

  if (! year_2050_test ())

    result |= 64;

  return result;

}]])],

       [gl_cv_func_working_mktime=yes],

       [gl_cv_func_working_mktime=no],

       [gl_cv_func_working_mktime="guessing no"])

    ])

])

dnl Main macro of module 'mktime'.

AC_DEFUN([gl_FUNC_MKTIME],

[

  AC_REQUIRE([gl_HEADER_TIME_H_DEFAULTS])

  AC_REQUIRE([AC_CANONICAL_HOST])

  AC_REQUIRE([gl_FUNC_MKTIME_WORKS])

  REPLACE_MKTIME=0

  if test "$gl_cv_func_working_mktime" != yes; then

    REPLACE_MKTIME=1

    AC_DEFINE([NEED_MKTIME_WORKING], [1],

      [Define if the compilation of mktime.c should define 'mktime'

       with the algorithmic workarounds.])

  fi

  case "$host_os" in

    mingw*)

      REPLACE_MKTIME=1

      AC_DEFINE([NEED_MKTIME_WINDOWS], [1],

        [Define if the compilation of mktime.c should define 'mktime'

         with the native Windows TZ workaround.])

      ;;

  esac

])

dnl Main macro of module 'mktime-internal'.

AC_DEFUN([gl_FUNC_MKTIME_INTERNAL], [

  AC_REQUIRE([gl_FUNC_MKTIME_WORKS])

  WANT_MKTIME_INTERNAL=0

  dnl BeOS has __mktime_internal in libc, but other platforms don't.

  AC_CHECK_FUNC([__mktime_internal],

    [AC_DEFINE([mktime_internal], [__mktime_internal],

       [Define to the real name of the mktime_internal function.])

    ],

    [dnl mktime works but it doesn't export __mktime_internal,

     dnl so we need to substitute our own mktime implementation.

     WANT_MKTIME_INTERNAL=1

     AC_DEFINE([NEED_MKTIME_INTERNAL], [1],

       [Define if the compilation of mktime.c should define 'mktime_internal'.])

    ])

])

# Prerequisites of lib/mktime.c.

AC_DEFUN([gl_PREREQ_MKTIME], [:])