Add the timegm Gnulib module

1 files changed, 224 insertions, 0 deletions

diff --git a/gl/m4/mktime.m4 b/gl/m4/mktime.m4
new file mode 100644
index 00000000..223b9f1f
--- /dev/null
+++ b/gl/m4/mktime.m4
@@ -0,0 +1,224 @@
+# serial 14
+dnl Copyright (C) 2002-2003, 2005-2007, 2009 Free Software Foundation, 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.
+
+# Redefine AC_FUNC_MKTIME, to fix a bug in Autoconf 2.61a and earlier.
+# This redefinition can be removed once a new version of Autoconf is assumed.
+# The redefinition is taken from
+# <http://cvs.sv.gnu.org/viewcvs/*checkout*/autoconf/autoconf/lib/autoconf/functions.m4?rev=1.119>.
+# AC_FUNC_MKTIME
+# --------------
+AC_DEFUN([AC_FUNC_MKTIME],
+[AC_CHECK_HEADERS_ONCE([unistd.h])
+AC_CHECK_FUNCS_ONCE([alarm])
+AC_CACHE_CHECK([for working mktime], [ac_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
+
+#ifndef HAVE_ALARM
+# define alarm(X) /* empty */
+#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 ()
+{
+  time_t t, delta;
+  int i, j;
+
+  /* This test makes some buggy mktime implementations loop.
+     Give up after 60 seconds; a mktime slower than that
+     isn't worth using anyway.  */
+  alarm (60);
+
+  for (;;)
+    {
+      t = (time_t_max << 1) + 1;
+      if (t <= time_t_max)
+        break;
+      time_t_max = t;
+    }
+  time_t_min = - ((time_t) ~ (time_t) 0 == (time_t) -1) - 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; t += delta)
+        if (! mktime_test (t))
+          return 1;
+      if (! (mktime_test ((time_t) 1)
+             && mktime_test ((time_t) (60 * 60))
+             && mktime_test ((time_t) (60 * 60 * 24))))
+        return 1;
+
+      for (j = 1; ; j <<= 1)
+        if (! bigtime_test (j))
+          return 1;
+        else if (INT_MAX / 2 < j)
+          break;
+      if (! bigtime_test (INT_MAX))
+        return 1;
+    }
+  return ! (irix_6_4_bug () && spring_forward_gap () && year_2050_test ());
+}]])],
+               [ac_cv_func_working_mktime=yes],
+               [ac_cv_func_working_mktime=no],
+               [ac_cv_func_working_mktime=no])])
+if test $ac_cv_func_working_mktime = no; then
+  AC_LIBOBJ([mktime])
+fi
+])# AC_FUNC_MKTIME
+
+AC_DEFUN([gl_FUNC_MKTIME],
+[
+  AC_FUNC_MKTIME
+  dnl Note: AC_FUNC_MKTIME does AC_LIBOBJ([mktime]).
+  if test $ac_cv_func_working_mktime = no; then
+    AC_DEFINE([mktime], [rpl_mktime],
+      [Define to rpl_mktime if the replacement function should be used.])
+    gl_PREREQ_MKTIME
+  fi
+])
+
+# Prerequisites of lib/mktime.c.
+AC_DEFUN([gl_PREREQ_MKTIME],
+[
+  AC_REQUIRE([AC_C_INLINE])
+])