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Diffstat (limited to 'gl/m4/mktime.m4')
| -rw-r--r-- | gl/m4/mktime.m4 | 224 |
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]) +]) |