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[PATCH 2/3] time_rz: new module
From: |
Paul Eggert |
Subject: |
[PATCH 2/3] time_rz: new module |
Date: |
Thu, 23 Jul 2015 18:31:31 -0700 |
* MODULES.html.sh: Add time_rz.
* lib/time_rz.c, m4/time_rz.m4, modules/time_rz: New files.
* lib/time.in.h (timezone_t, tzalloc, tzfree, localtime_rz, mktime_z):
New decls if _GNU_SOURCE && @GNULIB_TIME_RZ@ && ! @address@hidden
* m4/sys_time_h.m4 (gl_HEADER_SYS_TIME_H_DEFAULTS):
New var HAVE_TIMEZONE_T (default 0).
* m4/time_h.m4 (gl_HEADER_TIME_H_DEFAULTS):
New var GNULIB_TIME_RZ (default 0).
* modules/time (time.h): Substitute the new vars.
---
ChangeLog | 11 ++
MODULES.html.sh | 1 +
lib/time.in.h | 19 ++++
lib/time_rz.c | 336 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
m4/sys_time_h.m4 | 1 +
m4/time_h.m4 | 1 +
m4/time_rz.m4 | 21 ++++
modules/time | 2 +
modules/time_rz | 44 ++++++++
9 files changed, 436 insertions(+)
create mode 100644 lib/time_rz.c
create mode 100644 m4/time_rz.m4
create mode 100644 modules/time_rz
diff --git a/ChangeLog b/ChangeLog
index 775f5f2..4999362 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,16 @@
2015-07-23 Paul Eggert <address@hidden>
+ time_rz: new module
+ * MODULES.html.sh: Add time_rz.
+ * lib/time_rz.c, m4/time_rz.m4, modules/time_rz: New files.
+ * lib/time.in.h (timezone_t, tzalloc, tzfree, localtime_rz, mktime_z):
+ New decls if _GNU_SOURCE && @GNULIB_TIME_RZ@ && ! @address@hidden
+ * m4/sys_time_h.m4 (gl_HEADER_SYS_TIME_H_DEFAULTS):
+ New var HAVE_TIMEZONE_T (default 0).
+ * m4/time_h.m4 (gl_HEADER_TIME_H_DEFAULTS):
+ New var GNULIB_TIME_RZ (default 0).
+ * modules/time (time.h): Substitute the new vars.
+
flexmember: license is now unlimited
* modules/flexmember (License): Change to unlimited,
since its only source file gives an unlimited license.
diff --git a/MODULES.html.sh b/MODULES.html.sh
index 7835e9d..5b2c459 100755
--- a/MODULES.html.sh
+++ b/MODULES.html.sh
@@ -1725,6 +1725,7 @@ func_all_modules ()
func_begin_table
func_module fprintftime
func_module strftime
+ func_module time_rz
func_end_table
element="Extra functions based on ANSI C 89"
diff --git a/lib/time.in.h b/lib/time.in.h
index c374aeb..a5cb55d 100644
--- a/lib/time.in.h
+++ b/lib/time.in.h
@@ -231,6 +231,25 @@ _GL_CXXALIAS_SYS (strptime, char *, (char const *restrict
__buf,
_GL_CXXALIASWARN (strptime);
# endif
+# if defined _GNU_SOURCE && @GNULIB_TIME_RZ@ && ! @HAVE_TIMEZONE_T@
+typedef struct tm_zone *timezone_t;
+_GL_FUNCDECL_SYS (tzalloc, timezone_t, (char const *__name));
+_GL_CXXALIAS_SYS (tzalloc, timezone_t, (char const *__name));
+_GL_FUNCDECL_SYS (tzfree, void, (timezone_t __tz));
+_GL_CXXALIAS_SYS (tzfree, void, (timezone_t __tz));
+_GL_FUNCDECL_SYS (localtime_rz, struct tm *,
+ (timezone_t __tz, time_t const *restrict __timer,
+ struct tm *restrict __result) _GL_ARG_NONNULL ((2, 3)));
+_GL_CXXALIAS_SYS (localtime_rz, struct tm *,
+ (timezone_t __tz, time_t const *restrict __timer,
+ struct tm *restrict __result));
+_GL_FUNCDECL_SYS (mktime_z, time_t,
+ (timezone_t __tz, struct tm *restrict __result)
+ _GL_ARG_NONNULL ((2)));
+_GL_CXXALIAS_SYS (mktime_z, time_t,
+ (timezone_t __tz, struct tm *restrict __result));
+# endif
+
/* Convert TM to a time_t value, assuming UTC. */
# if @GNULIB_TIMEGM@
# if @REPLACE_TIMEGM@
diff --git a/lib/time_rz.c b/lib/time_rz.c
new file mode 100644
index 0000000..db1a382
--- /dev/null
+++ b/lib/time_rz.c
@@ -0,0 +1,336 @@
+/* Time zone functions such as tzalloc and localtime_rz
+
+ Copyright 2015 Free Software Foundation, Inc.
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 2, or (at your option)
+ any later version.
+
+ This program 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 General Public License for more details.
+
+ You should have received a copy of the GNU General Public License along
+ with this program; if not, see <http://www.gnu.org/licenses/>. */
+
+/* Written by Paul Eggert. */
+
+/* Although this module is not thread-safe, any races should be fairly
+ rare and reasonably benign. For complete thread-safety, use a C
+ library with a working timezone_t type, so that this module is not
+ needed. */
+
+#include <config.h>
+
+#include <time.h>
+
+#include <errno.h>
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdlib.h>
+#include <string.h>
+
+#if !HAVE_TZSET
+static void tzset (void) { }
+#endif
+
+/* A time zone rule. */
+struct tm_zone
+{
+ /* More abbreviations, should they be needed. Their TZ_IS_SET
+ members are zero. */
+ timezone_t next;
+
+ /* If nonzero, the rule represents the TZ environment variable set
+ to the first "abbreviation" (this may be the empty string).
+ Otherwise, it represents an unset TZ. */
+ char tz_is_set;
+
+ /* A sequence of null-terminated strings packed next to each other.
+ The strings are followed by an extra null byte. If TZ_IS_SET,
+ there must be at least one string and the first string (which is
+ actually a TZ environment value value) may be empty. Otherwise
+ all strings must be nonempty.
+
+ Abbreviations are stored here because otherwise the values of
+ tm_zone and/or tzname would be dead after changing TZ and calling
+ tzset. Abbreviations never move once allocated, and are live
+ until tzfree is called. */
+ char abbrs[FLEXIBLE_ARRAY_MEMBER];
+};
+
+/* The approximate size to use for small allocation requests. This is
+ the largest "small" request for the GNU C library malloc. */
+enum { DEFAULT_MXFAST = 64 * sizeof (size_t) / 4 };
+
+/* Minimum size of the ABBRS member of struct abbr. ABBRS is larger
+ only in the unlikely case where an abbreviation longer than this is
+ used. */
+enum { ABBR_SIZE_MIN = DEFAULT_MXFAST - offsetof (struct tm_zone, abbrs) };
+
+static char const TZ[] = "TZ";
+
+/* Magic cookie timezone_t value, for local time. It differs from
+ NULL and from all other timezone_t values. Only the address
+ matters; the pointer is never dereferenced. */
+static timezone_t local_tz = (timezone_t) 1;
+
+#if HAVE_TM_ZONE || HAVE_TZNAME
+
+/* Return true if the values A and B differ according to the rules for
+ tm_isdst: A and B differ if one is zero and the other positive. */
+static bool
+isdst_differ (int a, int b)
+{
+ return !a != !b && 0 <= a && 0 <= b;
+}
+
+/* Return true if A and B are equal. */
+static int
+equal_tm (const struct tm *a, const struct tm *b)
+{
+ return ! ((a->tm_sec ^ b->tm_sec)
+ | (a->tm_min ^ b->tm_min)
+ | (a->tm_hour ^ b->tm_hour)
+ | (a->tm_mday ^ b->tm_mday)
+ | (a->tm_mon ^ b->tm_mon)
+ | (a->tm_year ^ b->tm_year)
+ | isdst_differ (a->tm_isdst, b->tm_isdst));
+}
+
+#endif
+
+/* Copy to ABBRS the abbreviation at ABBR with size ABBR_SIZE (this
+ includes its trailing null byte). Append an extra null byte to
+ mark the end of ABBRS. */
+static void
+extend_abbrs (char *abbrs, char const *abbr, size_t abbr_size)
+{
+ memcpy (abbrs, abbr, abbr_size);
+ abbrs[abbr_size + 1] = '\0';
+}
+
+/* Return a newly allocated time zone for NAME, or NULL on failure.
+ As a special case, return a nonzero constant for wall clock time, a
+ constant that survives freeing. */
+timezone_t
+tzalloc (char const *name)
+{
+ size_t name_size = name ? strlen (name) + 1 : 0;
+ size_t abbr_size = name_size < ABBR_SIZE_MIN ? ABBR_SIZE_MIN : name_size + 1;
+ timezone_t tz = malloc (offsetof (struct tm_zone, abbrs) + abbr_size);
+ if (tz)
+ {
+ tz->next = NULL;
+ tz->tz_is_set = !!name;
+ extend_abbrs (tz->abbrs, name, name_size);
+ }
+ return tz;
+}
+
+/* Save into TZ any nontrivial time zone abbreviation used by TM,
+ and update *TM or tzname if they point to the abbreviation.
+ Return true if successful, false (setting errno) otherwise. */
+static bool
+save_abbr (timezone_t tz, struct tm *tm)
+{
+#if HAVE_TM_ZONE || HAVE_TZNAME
+ char const *zone = NULL;
+ char **tzname_zone = NULL;
+ char *zone_copy = (char *) "";
+# if HAVE_TM_ZONE
+ zone = tm->tm_zone;
+# endif
+# if HAVE_TZNAME
+ if (! (zone && *zone) && 0 <= tm->tm_isdst)
+ zone = *(tzname_zone = &tzname[0 < tm->tm_isdst]);
+# endif
+
+ /* No need to replace null zones, or zones within the struct tm. */
+ if (!zone || ((char *) tm <= zone && zone < (char *) (tm + 1)))
+ return true;
+
+ if (*zone)
+ {
+ zone_copy = tz->abbrs;
+
+ while (strcmp (zone_copy, zone) != 0)
+ {
+ if (! (*zone_copy || (zone_copy == tz->abbrs && tz->tz_is_set)))
+ {
+ size_t zone_size = strlen (zone) + 1;
+ if (zone_size < tz->abbrs + ABBR_SIZE_MIN - zone_copy)
+ extend_abbrs (zone_copy, zone, zone_size);
+ else
+ {
+ tz = tz->next = tzalloc (zone);
+ if (!tz)
+ return false;
+ tz->tz_is_set = 0;
+ zone_copy = tz->abbrs;
+ }
+ break;
+ }
+
+ zone_copy += strlen (zone_copy) + 1;
+ if (!*zone_copy && tz->next)
+ {
+ tz = tz->next;
+ zone_copy = tz->abbrs;
+ }
+ }
+ }
+
+ /* Replace the zone name so that its lifetime matches that of TZ. */
+# if HAVE_TM_ZONE
+ if (!tzname_zone)
+ tm->tm_zone = zone_copy;
+# endif
+# if HAVE_TZNAME
+ if (tzname_zone)
+ *tzname_zone = zone_copy;
+# endif
+#endif
+ return true;
+}
+
+/* Free a time zone. */
+void
+tzfree (timezone_t tz)
+{
+ if (tz != local_tz)
+ while (tz)
+ {
+ timezone_t next = tz->next;
+ free (tz);
+ tz = next;
+ }
+}
+
+/* Get and set the TZ environment variable. These functions can be
+ overridden by programs like Emacs that manage their own environment. */
+
+#ifndef getenv_TZ
+static char *
+getenv_TZ (void)
+{
+ return getenv (TZ);
+}
+#endif
+
+#ifndef setenv_TZ
+static int
+setenv_TZ (char const *tz)
+{
+ return tz ? setenv (TZ, tz, 1) : unsetenv (TZ);
+}
+#endif
+
+/* Change the environment to match the specified timezone_t value.
+ Return true if successful, false (setting errno) otherwise. */
+static bool
+change_env (timezone_t tz)
+{
+ if (setenv_TZ (tz->tz_is_set ? tz->abbrs : NULL) != 0)
+ return false;
+ tzset ();
+ return true;
+}
+
+/* Temporarily set the time zone to TZ, which must not be null.
+ Return LOCAL_TZ if the time zone setting is already correct.
+ Otherwise return a newly allocated time zone representing the old
+ setting, or NULL (setting errno) on failure. */
+static timezone_t
+set_tz (timezone_t tz)
+{
+ char *env_tz = getenv_TZ ();
+ if (env_tz
+ ? tz->tz_is_set && strcmp (tz->abbrs, env_tz) == 0
+ : !tz->tz_is_set)
+ return local_tz;
+ else
+ {
+ timezone_t old_tz = tzalloc (env_tz);
+ if (!old_tz)
+ return old_tz;
+ if (! change_env (tz))
+ {
+ int saved_errno = errno;
+ tzfree (old_tz);
+ errno = saved_errno;
+ return NULL;
+ }
+ return old_tz;
+ }
+}
+
+/* Restore an old setting returned by set_tz. It must not be null.
+ Return true (preserving errno) if successful, false (setting errno)
+ otherwise. */
+static bool
+revert_tz (timezone_t tz)
+{
+ if (tz == local_tz)
+ return true;
+ else
+ {
+ int saved_errno = errno;
+ bool ok = change_env (tz);
+ if (!ok)
+ saved_errno = errno;
+ tzfree (tz);
+ errno = saved_errno;
+ return ok;
+ }
+}
+
+/* Use time zone TZ to compute localtime_r (T, TM). */
+struct tm *
+localtime_rz (timezone_t tz, time_t const *t, struct tm *tm)
+{
+ if (!tz)
+ return gmtime_r (t, tm);
+ else
+ {
+ timezone_t old_tz = set_tz (tz);
+ if (old_tz)
+ {
+ tm = localtime_r (t, tm);
+ if (tm && !save_abbr (tz, tm))
+ tm = NULL;
+ if (revert_tz (old_tz))
+ return tm;
+ }
+ return NULL;
+ }
+}
+
+/* Use time zone TZ to compute mktime (TM). */
+time_t
+mktime_z (timezone_t tz, struct tm *tm)
+{
+ if (!tz)
+ return timegm (tm);
+ else
+ {
+ timezone_t old_tz = set_tz (tz);
+ if (old_tz)
+ {
+ time_t t = mktime (tm);
+#if HAVE_TM_ZONE || HAVE_TZNAME
+ time_t badtime = -1;
+ struct tm tm_1;
+ if ((t != badtime
+ || (localtime_r (&t, &tm_1) && equal_tm (tm, &tm_1)))
+ && !save_abbr (tz, tm))
+ t = badtime;
+#endif
+ if (revert_tz (old_tz))
+ return t;
+ }
+ return -1;
+ }
+}
diff --git a/m4/sys_time_h.m4 b/m4/sys_time_h.m4
index 50133b9..28c8b1a 100644
--- a/m4/sys_time_h.m4
+++ b/m4/sys_time_h.m4
@@ -105,6 +105,7 @@ AC_DEFUN([gl_HEADER_SYS_TIME_H_DEFAULTS],
HAVE_GETTIMEOFDAY=1; AC_SUBST([HAVE_GETTIMEOFDAY])
HAVE_STRUCT_TIMEVAL=1; AC_SUBST([HAVE_STRUCT_TIMEVAL])
HAVE_SYS_TIME_H=1; AC_SUBST([HAVE_SYS_TIME_H])
+ HAVE_TIMEZONE_T=0; AC_SUBST([HAVE_TIMEZONE_T])
REPLACE_GETTIMEOFDAY=0; AC_SUBST([REPLACE_GETTIMEOFDAY])
REPLACE_STRUCT_TIMEVAL=0; AC_SUBST([REPLACE_STRUCT_TIMEVAL])
])
diff --git a/m4/time_h.m4 b/m4/time_h.m4
index d9c41a4..754b469 100644
--- a/m4/time_h.m4
+++ b/m4/time_h.m4
@@ -109,6 +109,7 @@ AC_DEFUN([gl_HEADER_TIME_H_DEFAULTS],
GNULIB_STRPTIME=0; AC_SUBST([GNULIB_STRPTIME])
GNULIB_TIMEGM=0; AC_SUBST([GNULIB_TIMEGM])
GNULIB_TIME_R=0; AC_SUBST([GNULIB_TIME_R])
+ GNULIB_TIME_RZ=0; AC_SUBST([GNULIB_TIME_RZ])
dnl Assume proper GNU behavior unless another module says otherwise.
HAVE_DECL_LOCALTIME_R=1; AC_SUBST([HAVE_DECL_LOCALTIME_R])
HAVE_NANOSLEEP=1; AC_SUBST([HAVE_NANOSLEEP])
diff --git a/m4/time_rz.m4 b/m4/time_rz.m4
new file mode 100644
index 0000000..0c1f2c3
--- /dev/null
+++ b/m4/time_rz.m4
@@ -0,0 +1,21 @@
+dnl Time zone functions: tzalloc, localtime_rz, etc.
+
+dnl Copyright (C) 2015 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 Written by Paul Eggert.
+
+AC_DEFUN([gl_TIME_RZ],
+[
+ AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
+ AC_REQUIRE([gl_HEADER_SYS_TIME_H_DEFAULTS])
+ AC_REQUIRE([AC_STRUCT_TIMEZONE])
+ AC_CHECK_FUNCS_ONCE([tzset])
+
+ AC_CHECK_TYPES([timezone_t], [], [], [[#include <time.h>]])
+ if test "$ac_cv_type_timezone_t" = yes; then
+ HAVE_TIMEZONE_T=1
+ fi
+])
diff --git a/modules/time b/modules/time
index 55edc25..d12add0 100644
--- a/modules/time
+++ b/modules/time
@@ -36,10 +36,12 @@ time.h: time.in.h $(top_builddir)/config.status
$(CXXDEFS_H) $(ARG_NONNULL_H) $(
-e 's/@''GNULIB_STRPTIME''@/$(GNULIB_STRPTIME)/g' \
-e 's/@''GNULIB_TIMEGM''@/$(GNULIB_TIMEGM)/g' \
-e 's/@''GNULIB_TIME_R''@/$(GNULIB_TIME_R)/g' \
+ -e 's/@''GNULIB_TIME_RZ''@/$(GNULIB_TIME_RZ)/g' \
-e 's|@''HAVE_DECL_LOCALTIME_R''@|$(HAVE_DECL_LOCALTIME_R)|g' \
-e 's|@''HAVE_NANOSLEEP''@|$(HAVE_NANOSLEEP)|g' \
-e 's|@''HAVE_STRPTIME''@|$(HAVE_STRPTIME)|g' \
-e 's|@''HAVE_TIMEGM''@|$(HAVE_TIMEGM)|g' \
+ -e 's|@''HAVE_TIMEZONE_T''@|$(HAVE_TIMEZONE_T)|g' \
-e 's|@''REPLACE_GMTIME''@|$(REPLACE_GMTIME)|g' \
-e 's|@''REPLACE_LOCALTIME''@|$(REPLACE_LOCALTIME)|g' \
-e 's|@''REPLACE_LOCALTIME_R''@|$(REPLACE_LOCALTIME_R)|g' \
diff --git a/modules/time_rz b/modules/time_rz
new file mode 100644
index 0000000..765e9e4
--- /dev/null
+++ b/modules/time_rz
@@ -0,0 +1,44 @@
+Description:
+Reentrant time zone functions: localtime_rz, mktime_z, etc.
+
+Comment:
+This implements the NetBSD-inspired extensions to <time.h>, which
+defines a type timezone_t and associated allocation functions tzalloc
+and tzfree, along with two functions localtime_rz and mktime_z that
+are like localtime_r and mktime except they have a new leading
+timezone_t argument. Time zone abbreviation strings have lifetimes
+equal to the corresponding struct tm or timezone_t object (whichever
+is less). tzalloc (X) yields a time zone object equivalent to setting
+the TZ environment variable to X. tzalloc (NULL) is the same as an
+unset TZ environment variable. (timezone_t) 0 stands for UTC.
+
+Files:
+lib/time_rz.c
+m4/time_rz.m4
+
+Depends-on:
+extensions
+flexmember [test "$HAVE_TIMEZONE_T" = 0]
+setenv [test "$HAVE_TIMEZONE_T" = 0]
+stdbool [test "$HAVE_TIMEZONE_T" = 0]
+time_r [test "$HAVE_TIMEZONE_T" = 0]
+timegm [test "$HAVE_TIMEZONE_T" = 0]
+unsetenv [test "$HAVE_TIMEZONE_T" = 0]
+
+configure.ac:
+gl_TIME_RZ
+if test "$HAVE_TIMEZONE_T" = 0; then
+ AC_LIBOBJ([time_rz])
+fi
+gl_TIME_MODULE_INDICATOR([time_rz])
+
+Makefile.am:
+
+Include:
+<time.h>
+
+License:
+LGPLv2+
+
+Maintainer:
+Paul Eggert
--
2.1.0