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Fri Sep 29 03:43:51 1995 Paul Eggert <eggert@twinsun.com>
Rewrite mktime from scratch for performance, and for correctness in the presence of leap seconds. * time/mktime.c (ydhms_tm_diff, not_equal_tm, print_tm, check_result): New functions. (LEAP_SECONDS_POSSIBLE, CHAR_BIT, INT_MIN, INT_MAX, TIME_T_MIN, TIME_T_MAX, TM_YEAR_BASE, EPOCH_YEAR): New macros. <limits.h>, <stdlib.h>: New #includes. (main): Support tests with given broken-down value; support benchmarks. (__mon_lengths, debugging_enabled, printtm, dist_tm, doit, do_normalization, normalize, BAD_STRUCT_TM, SKIP_VALUE, <ctype.h>): Remove. * time/time.h, time/mktime.c (__mktime_internal): New offset arg. * time/mktime.c (mktime), time/timegm.c (timegm): Use it. * time/mktime.c (__mon_yday): New variable; replaces `__mon_lengths'. time/offtime.c (__offtime), time/tzset.c (compute_change): Use it. * time/offtime.c (__offtime): Remove useless assignment `tp->tm_isdst = -1'. * manual/maint.texi: Update credits. Fri Oct 6 00:28:53 1995 Roland McGrath <roland@churchy.gnu.ai.mit.edu> * sysdeps/unix/common/readv.S: Moved to sysdeps/unix/bsd. * sysdeps/unix/common/writev.S: Moved to sysdeps/unix/bsd. * sysdeps/unix/sysv/linux/readv.c: File removed. * sysdeps/unix/sysv/linux/writev.c: File removed. * sysdeps/unix/configure.in: Check for readv and writev syscalls. * sysdeps/unix/configure.in: If eval doesn't set $unix_srcname, set it to $unix_syscall instead of $unix_function.
This commit is contained in:
Roland McGrath
parent
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ChangeLog
37
ChangeLog
@ -1,3 +1,40 @@
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Fri Sep 29 03:43:51 1995 Paul Eggert <eggert@twinsun.com>
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Rewrite mktime from scratch for performance, and for correctness
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in the presence of leap seconds.
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* time/mktime.c (ydhms_tm_diff, not_equal_tm, print_tm, check_result):
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New functions.
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(LEAP_SECONDS_POSSIBLE, CHAR_BIT, INT_MIN, INT_MAX,
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TIME_T_MIN, TIME_T_MAX, TM_YEAR_BASE, EPOCH_YEAR): New macros.
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<limits.h>, <stdlib.h>: New #includes.
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(main): Support tests with given broken-down value; support benchmarks.
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(__mon_lengths, debugging_enabled, printtm, dist_tm, doit,
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do_normalization, normalize, BAD_STRUCT_TM, SKIP_VALUE,
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<ctype.h>): Remove.
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* time/time.h, time/mktime.c (__mktime_internal): New offset arg.
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* time/mktime.c (mktime), time/timegm.c (timegm): Use it.
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* time/mktime.c (__mon_yday): New variable; replaces `__mon_lengths'.
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time/offtime.c (__offtime), time/tzset.c (compute_change): Use it.
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* time/offtime.c (__offtime): Remove useless assignment
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`tp->tm_isdst = -1'.
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* manual/maint.texi: Update credits.
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Fri Oct 6 00:28:53 1995 Roland McGrath <roland@churchy.gnu.ai.mit.edu>
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* sysdeps/unix/common/readv.S: Moved to sysdeps/unix/bsd.
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* sysdeps/unix/common/writev.S: Moved to sysdeps/unix/bsd.
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* sysdeps/unix/sysv/linux/readv.c: File removed.
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* sysdeps/unix/sysv/linux/writev.c: File removed.
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* sysdeps/unix/configure.in: Check for readv and writev syscalls.
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* sysdeps/unix/configure.in: If eval doesn't set $unix_srcname,
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set it to $unix_syscall instead of $unix_function.
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Thu Oct 5 00:59:58 1995 Roland McGrath <roland@churchy.gnu.ai.mit.edu>
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* elf/rtld.c (dl_main): Grok --list flag.
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@ -774,7 +774,7 @@ The startup code to support SunOS shared libraries was contributed by
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Tom Quinn.
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@item
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The @code{mktime} function was contributed by Noel Cragg.
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The @code{mktime} function was contributed by Paul Eggert.
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@item
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The port to the Sequent Symmetry running Dynix version 3
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@ -72,7 +72,7 @@ for unix_function in \
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getitimer setitimer \
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getdomainname/getdomain=bsd/bsd4.4 \
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setdomainname/setdomain=bsd/bsd4.4 \
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profil=bsd \
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profil=bsd readv=bsd writev=bsd \
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getpriority setpriority \
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getrlimit setrlimit
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do
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@ -85,7 +85,7 @@ do
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eval "unix_syscall=`echo $unix_function | \
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sed -e 's@=\(.*\)$@ unix_srcdir=\1@' \
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-e 's@/\(.*\)$@ unix_srcname=\1@'`"
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test -z "$unix_srcname" && unix_srcname=$unix_function
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test -z "$unix_srcname" && unix_srcname=$unix_syscall
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unix_implementor=none
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for unix_dir in $sysnames; do
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@ -97,11 +97,13 @@ do
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fi
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done
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# mkdir and rmdir have implementations in unix/sysv, but
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# the simple syscall versions are preferable if available.
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test $unix_syscall = mkdir -o $unix_syscall = rmdir && \
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test $unix_implementor = unix/sysv && \
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unix_implementor=generic
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case $unix_syscall in
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mkdir|rmdir)
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# mkdir and rmdir have implementations in unix/sysv, but
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# the simple syscall versions are preferable if available.
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test $unix_implementor = unix/sysv && unix_implementor=generic
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;;
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esac
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case $unix_implementor in
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none|stub|generic|posix)
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@ -1 +0,0 @@
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#include <sysdeps/posix/readv.c>
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@ -1 +0,0 @@
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#include <sysdeps/posix/writev.c>
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763
time/mktime.c
763
time/mktime.c
@ -1,7 +1,5 @@
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/* Copyright (C) 1993, 1994, 1995 Free Software Foundation, Inc.
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Contributed by Noel Cragg (noel@cs.oberlin.edu), with fixes by
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Michael E. Calwas (calwas@ttd.teradyne.com) and
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Wade Hampton (tasi029@tmn.com).
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Contributed by Paul Eggert (eggert@twinsun.com).
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This file is part of the GNU C Library.
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@ -22,23 +20,35 @@ Cambridge, MA 02139, USA. */
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/* Define this to have a standalone program to test this implementation of
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mktime. */
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/* #define DEBUG */
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/* #define DEBUG 1 */
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#ifdef HAVE_CONFIG_H
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#include <config.h>
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#endif
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/* Assume that leap seconds are possible, unless told otherwise.
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If the host has a `zic' command with a `-L leapsecondfilename' option,
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then it supports leap seconds; otherwise it probably doesn't. */
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#ifndef LEAP_SECONDS_POSSIBLE
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#define LEAP_SECONDS_POSSIBLE 1
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#endif
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#include <sys/types.h> /* Some systems define `time_t' here. */
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#include <time.h>
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#ifndef __isleap
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/* Nonzero if YEAR is a leap year (every 4 years,
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except every 100th isn't, and every 400th is). */
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#define __isleap(year) \
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((year) % 4 == 0 && ((year) % 100 != 0 || (year) % 400 == 0))
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#if __STDC__ || __GNU_LIBRARY__ || STDC_HEADERS
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#include <limits.h>
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#endif
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#if DEBUG
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#include <stdio.h>
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#if __STDC__ || __GNU_LIBRARY__ || STDC_HEADERS
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#include <stdlib.h>
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#endif
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/* Make it work even if the system's libc has its own mktime routine. */
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#define mktime my_mktime
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#endif /* DEBUG */
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#ifndef __P
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#if defined (__GNUC__) || (defined (__STDC__) && __STDC__)
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#define __P(args) args
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@ -47,370 +57,62 @@ Cambridge, MA 02139, USA. */
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#endif /* GCC. */
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#endif /* Not __P. */
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/* How many days are in each month. */
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const unsigned short int __mon_lengths[2][12] =
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#ifndef CHAR_BIT
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#define CHAR_BIT 8
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#endif
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#ifndef INT_MIN
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#define INT_MIN (~0 << (sizeof (int) * CHAR_BIT - 1))
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#endif
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#ifndef INT_MAX
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#define INT_MAX (~0 - INT_MIN)
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#endif
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#ifndef TIME_T_MIN
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#define TIME_T_MIN (0 < (time_t) -1 ? (time_t) 0 \
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: ~ (time_t) 0 << (sizeof (time_t) * CHAR_BIT - 1))
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#endif
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#ifndef TIME_T_MAX
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#define TIME_T_MAX (~ (time_t) 0 - TIME_T_MIN)
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#endif
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#define TM_YEAR_BASE 1900
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#define EPOCH_YEAR 1970
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#ifndef __isleap
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/* Nonzero if YEAR is a leap year (every 4 years,
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except every 100th isn't, and every 400th is). */
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#define __isleap(year) \
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((year) % 4 == 0 && ((year) % 100 != 0 || (year) % 400 == 0))
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#endif
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/* How many days come before each month (0-12). */
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const unsigned short int __mon_yday[2][13] =
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{
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/* Normal years. */
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{ 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 },
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{ 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365 },
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/* Leap years. */
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{ 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 }
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{ 0, 31, 60, 91, 121, 152, 182, 213, 244, 274, 305, 335, 366 }
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};
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static time_t ydhms_tm_diff __P ((int, int, int, int, int, const struct tm *));
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time_t __mktime_internal __P ((struct tm *,
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struct tm *(*) (const time_t *, struct tm *),
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time_t *));
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static int times_through_search; /* This library routine should never
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hang -- make sure we always return
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when we're searching for a value */
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#ifdef DEBUG
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#include <stdio.h>
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#include <ctype.h>
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int debugging_enabled = 0;
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/* Print the values in a `struct tm'. */
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static void
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printtm (it)
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struct tm *it;
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{
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printf ("%02d/%02d/%04d %02d:%02d:%02d (%s) yday:%03d dst:%d gmtoffset:%ld",
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it->tm_mon + 1,
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it->tm_mday,
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it->tm_year + 1900,
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it->tm_hour,
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it->tm_min,
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it->tm_sec,
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it->tm_zone,
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it->tm_yday,
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it->tm_isdst,
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it->tm_gmtoff);
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}
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#endif
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static time_t
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dist_tm (t1, t2)
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struct tm *t1;
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struct tm *t2;
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{
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time_t distance = 0;
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unsigned long int v1, v2;
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int diff_flag = 0;
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v1 = v2 = 0;
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#define doit(x, secs) \
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v1 += t1->x * secs; \
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v2 += t2->x * secs; \
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if (!diff_flag) \
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{ \
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if (t1->x < t2->x) \
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diff_flag = -1; \
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else if (t1->x > t2->x) \
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diff_flag = 1; \
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}
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doit (tm_year, 31536000); /* Okay, not all years have 365 days. */
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doit (tm_mon, 2592000); /* Okay, not all months have 30 days. */
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doit (tm_mday, 86400);
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doit (tm_hour, 3600);
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doit (tm_min, 60);
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doit (tm_sec, 1);
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#undef doit
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/* We should also make sure that the sign of DISTANCE is correct -- if
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DIFF_FLAG is positive, the distance should be positive and vice versa. */
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distance = (v1 > v2) ? (v1 - v2) : (v2 - v1);
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if (diff_flag < 0)
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distance = -distance;
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if (times_through_search > 20) /* Arbitrary # of calls, but makes sure we
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never hang if there's a problem with
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this algorithm. */
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{
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distance = diff_flag;
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}
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/* We need this DIFF_FLAG business because it is forseeable that the
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distance may be zero when, in actuality, the two structures are
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different. This is usually the case when the dates are 366 days apart
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and one of the years is a leap year. */
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if (distance == 0 && diff_flag)
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distance = 86400 * diff_flag;
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return distance;
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}
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/* MKTIME converts the values in a struct tm to a time_t. The values
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in tm_wday and tm_yday are ignored; other values can be put outside
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of legal ranges since they will be normalized. This routine takes
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care of that normalization. */
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void
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do_normalization (tmptr)
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struct tm *tmptr;
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{
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#define normalize(foo,x,y,bar); \
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while (tmptr->foo < x) \
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{ \
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tmptr->bar--; \
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tmptr->foo = (y - (x - tmptr->foo) + 1); \
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} \
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while (tmptr->foo > y) \
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{ \
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tmptr->foo = (x + (tmptr->foo - y) - 1); \
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tmptr->bar++; \
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}
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normalize (tm_sec, 0, 59, tm_min);
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normalize (tm_min, 0, 59, tm_hour);
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normalize (tm_hour, 0, 23, tm_mday);
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/* Do the month first, so day range can be found. */
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normalize (tm_mon, 0, 11, tm_year);
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/* Since the day range modifies the month, we should be careful how
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we reference the array of month lengths -- it is possible that
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the month will go negative, hence the modulo...
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Also, tm_year is the year - 1900, so we have to 1900 to have it
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work correctly. */
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normalize (tm_mday, 1,
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__mon_lengths[__isleap (tmptr->tm_year + 1900)]
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[((tmptr->tm_mon < 0)
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? (12 + (tmptr->tm_mon % 12))
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: (tmptr->tm_mon % 12)) ],
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tm_mon);
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/* Do the month again, because the day may have pushed it out of range. */
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normalize (tm_mon, 0, 11, tm_year);
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/* Do the day again, because the month may have changed the range. */
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normalize (tm_mday, 1,
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__mon_lengths[__isleap (tmptr->tm_year + 1900)]
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[((tmptr->tm_mon < 0)
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? (12 + (tmptr->tm_mon % 12))
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: (tmptr->tm_mon % 12)) ],
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tm_mon);
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#ifdef DEBUG
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if (debugging_enabled)
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{
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printf (" After normalizing:\n ");
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printtm (tmptr);
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putchar ('\n');
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}
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#endif
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}
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/* Here's where the work gets done. */
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#define BAD_STRUCT_TM ((time_t) -1)
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time_t
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__mktime_internal (timeptr, producer)
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struct tm *timeptr;
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struct tm *(*producer) __P ((const time_t *, struct tm *));
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{
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struct tm our_tm; /* our working space */
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struct tm *me = &our_tm; /* a pointer to the above */
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time_t result; /* the value we return */
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*me = *timeptr; /* copy the struct tm that was passed
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in by the caller */
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/***************************/
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/* Normalize the structure */
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/***************************/
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/* This routine assumes that the value of TM_ISDST is -1, 0, or 1.
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If the user didn't pass it in that way, fix it. */
|
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if (me->tm_isdst > 0)
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me->tm_isdst = 1;
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else if (me->tm_isdst < 0)
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me->tm_isdst = -1;
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do_normalization (me);
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/* Get out of here if it's not possible to represent this struct.
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If any of the values in the normalized struct tm are negative,
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our algorithms won't work. Luckily, we only need to check the
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year at this point; normalization guarantees that all values will
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be in correct ranges EXCEPT the year. */
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if (me->tm_year < 0)
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return BAD_STRUCT_TM;
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/*************************************************/
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/* Find the appropriate time_t for the structure */
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/*************************************************/
|
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|
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/* Modified b-search -- make intelligent guesses as to where the
|
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time might lie along the timeline, assuming that our target time
|
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lies a linear distance (w/o considering time jumps of a
|
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particular region).
|
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|
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Assume that time does not fluctuate at all along the timeline --
|
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e.g., assume that a day will always take 86400 seconds, etc. --
|
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and come up with a hypothetical value for the time_t
|
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representation of the struct tm TARGET, in relation to the guess
|
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variable -- it should be pretty close!
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|
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After testing this, the maximum number of iterations that I had
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on any number that I tried was 3! Not bad.
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|
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The reason this is not a subroutine is that we will modify some
|
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fields in the struct tm (yday and mday). I've never felt good
|
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about side-effects when writing structured code... */
|
||||
|
||||
{
|
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struct tm *guess_tm;
|
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struct tm guess_struct;
|
||||
time_t guess = 0;
|
||||
time_t distance = 0;
|
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time_t last_distance = 0;
|
||||
|
||||
times_through_search = 0;
|
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|
||||
do
|
||||
{
|
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guess += distance;
|
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|
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times_through_search++;
|
||||
|
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guess_tm = (*producer) (&guess, &guess_struct);
|
||||
|
||||
#ifdef DEBUG
|
||||
if (debugging_enabled)
|
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{
|
||||
printf (" Guessing time_t == %d\n ", (int) guess);
|
||||
printtm (guess_tm);
|
||||
putchar ('\n');
|
||||
}
|
||||
#endif
|
||||
|
||||
/* How far is our guess from the desired struct tm? */
|
||||
distance = dist_tm (me, guess_tm);
|
||||
|
||||
/* Handle periods of time where a period of time is skipped.
|
||||
For example, 2:15 3 April 1994 does not exist, because DST
|
||||
is in effect. The distance function will alternately
|
||||
return values of 3600 and -3600, because it doesn't know
|
||||
that the requested time doesn't exist. In these situations
|
||||
(even if the skip is not exactly an hour) the distances
|
||||
returned will be the same, but alternating in sign. We
|
||||
want the later time, so check to see that the distance is
|
||||
oscillating and we've chosen the correct of the two
|
||||
possibilities.
|
||||
|
||||
Useful: 3 Apr 94 765356300, 30 Oct 94 783496000 */
|
||||
|
||||
if ((distance == -last_distance) && (distance < last_distance))
|
||||
{
|
||||
/* If the caller specified that the DST flag was off, it's
|
||||
not possible to represent this time. */
|
||||
if (me->tm_isdst == 0)
|
||||
{
|
||||
#ifdef DEBUG
|
||||
printf (" Distance is oscillating -- dst flag nixes struct!\n");
|
||||
#endif
|
||||
return BAD_STRUCT_TM;
|
||||
}
|
||||
|
||||
#ifdef DEBUG
|
||||
printf (" Distance is oscillating -- chose the later time.\n");
|
||||
#endif
|
||||
distance = 0;
|
||||
}
|
||||
|
||||
if ((distance == 0) && (me->tm_isdst != -1)
|
||||
&& (me->tm_isdst != guess_tm->tm_isdst))
|
||||
{
|
||||
/* If we're in this code, we've got the right time but the
|
||||
wrong daylight savings flag. We need to move away from
|
||||
the time that we have and approach the other time from
|
||||
the other direction. That is, if I've requested the
|
||||
non-DST version of a time and I get the DST version
|
||||
instead, I want to put us forward in time and search
|
||||
backwards to get the other time. I checked all of the
|
||||
configuration files for the tz package -- no entry
|
||||
saves more than two hours, so I think we'll be safe by
|
||||
moving 24 hours in one direction. IF THE AMOUNT OF
|
||||
TIME SAVED IN THE CONFIGURATION FILES CHANGES, THIS
|
||||
VALUE MAY NEED TO BE ADJUSTED. Luckily, we can never
|
||||
have more than one level of overlaps, or this would
|
||||
never work. */
|
||||
|
||||
#define SKIP_VALUE 86400
|
||||
|
||||
if (guess_tm->tm_isdst == 0)
|
||||
/* we got the later one, but want the earlier one */
|
||||
distance = -SKIP_VALUE;
|
||||
else
|
||||
distance = SKIP_VALUE;
|
||||
|
||||
#ifdef DEBUG
|
||||
printf (" Got the right time, wrong DST value -- adjusting\n");
|
||||
#endif
|
||||
}
|
||||
|
||||
last_distance = distance;
|
||||
|
||||
} while (distance != 0);
|
||||
|
||||
/* Check to see that the dst flag matches */
|
||||
|
||||
if (me->tm_isdst != -1)
|
||||
{
|
||||
if (me->tm_isdst != guess_tm->tm_isdst)
|
||||
{
|
||||
#ifdef DEBUG
|
||||
printf (" DST flag doesn't match! FIXME?\n");
|
||||
#endif
|
||||
return BAD_STRUCT_TM;
|
||||
}
|
||||
}
|
||||
|
||||
result = guess; /* Success! */
|
||||
|
||||
/* On successful completion, the values of tm_wday and tm_yday
|
||||
have to be set appropriately. */
|
||||
|
||||
/* me->tm_yday = guess_tm->tm_yday;
|
||||
me->tm_mday = guess_tm->tm_mday; */
|
||||
|
||||
*me = *guess_tm;
|
||||
}
|
||||
|
||||
/* Update the caller's version of the structure */
|
||||
|
||||
*timeptr = *me;
|
||||
|
||||
return result;
|
||||
}
|
||||
|
||||
#if ! HAVE_LOCALTIME_R && ! defined (localtime_r)
|
||||
#ifdef _LIBC
|
||||
#define localtime_r __localtime_r
|
||||
#else
|
||||
/* Approximate localtime_r as best we can in its absence. */
|
||||
#define localtime_r my_localtime_r /* Avoid clash with system localtime_r. */
|
||||
#define localtime_r my_localtime_r
|
||||
static struct tm *localtime_r __P ((const time_t *, struct tm *));
|
||||
static struct tm *
|
||||
localtime_r (t, tp)
|
||||
const time_t *t;
|
||||
struct tm *tp;
|
||||
{
|
||||
{
|
||||
struct tm *l = localtime (t);
|
||||
if (! l)
|
||||
return 0;
|
||||
@ -420,108 +122,287 @@ localtime_r (t, tp)
|
||||
#endif /* ! _LIBC */
|
||||
#endif /* ! HAVE_LOCALTIME_R && ! defined (localtime_r) */
|
||||
|
||||
time_t
|
||||
#ifdef DEBUG /* make it work even if the system's
|
||||
libc has it's own mktime routine */
|
||||
my_mktime (timeptr)
|
||||
#else
|
||||
mktime (timeptr)
|
||||
#endif
|
||||
struct tm *timeptr;
|
||||
|
||||
/* Yield the difference between (YEAR-YDAY HOUR:MIN:SEC) and (*TP),
|
||||
measured in seconds, ignoring leap seconds.
|
||||
YEAR uses the same numbering as TM->tm_year.
|
||||
All values are in range, except possibly YEAR.
|
||||
If overflow occurs, yield the low order bits of the correct answer. */
|
||||
static time_t
|
||||
ydhms_tm_diff (year, yday, hour, min, sec, tp)
|
||||
int year, yday, hour, min, sec;
|
||||
const struct tm *tp;
|
||||
{
|
||||
return __mktime_internal (timeptr, localtime_r);
|
||||
time_t ay = year + (time_t) (TM_YEAR_BASE - 1);
|
||||
time_t by = tp->tm_year + (time_t) (TM_YEAR_BASE - 1);
|
||||
time_t intervening_leap_days =
|
||||
(ay/4 - by/4) - (ay/100 - by/100) + (ay/400 - by/400);
|
||||
time_t years = ay - by;
|
||||
time_t days = (365 * years + intervening_leap_days
|
||||
+ (yday - tp->tm_yday));
|
||||
return (60 * (60 * (24 * days + (hour - tp->tm_hour))
|
||||
+ (min - tp->tm_min))
|
||||
+ (sec - tp->tm_sec));
|
||||
}
|
||||
|
||||
|
||||
/* Convert *TP to a time_t value. */
|
||||
time_t
|
||||
mktime (tp)
|
||||
struct tm *tp;
|
||||
{
|
||||
static time_t localtime_offset;
|
||||
return __mktime_internal (tp, localtime_r, &localtime_offset);
|
||||
}
|
||||
|
||||
/* Convert *TP to a time_t value, inverting
|
||||
the monotonic and mostly-unit-linear conversion function CONVERT.
|
||||
Use *OFFSET to keep track of a guess at the offset of the result,
|
||||
compared to what the result would be for UTC without leap seconds.
|
||||
If *OFFSET's guess is correct, only one CONVERT call is needed. */
|
||||
time_t
|
||||
__mktime_internal (tp, convert, offset)
|
||||
struct tm *tp;
|
||||
struct tm *(*convert) __P ((const time_t *, struct tm *));
|
||||
time_t *offset;
|
||||
{
|
||||
time_t t, dt, t0;
|
||||
struct tm tm;
|
||||
|
||||
/* The maximum number of probes (calls to CONVERT) should be enough
|
||||
to handle any combinations of time zone rule changes, solar time,
|
||||
and leap seconds. Posix.1 prohibits leap seconds, but some hosts
|
||||
have them anyway. */
|
||||
int remaining_probes = 4;
|
||||
|
||||
/* Time requested. Copy it in case CONVERT modifies *TP; this can
|
||||
occur if TP is localtime's returned value and CONVERT is localtime. */
|
||||
int sec = tp->tm_sec;
|
||||
int min = tp->tm_min;
|
||||
int hour = tp->tm_hour;
|
||||
int mday = tp->tm_mday;
|
||||
int mon = tp->tm_mon;
|
||||
int year_requested = tp->tm_year;
|
||||
int isdst = tp->tm_isdst;
|
||||
|
||||
/* Ensure that mon is in range, and set year accordingly. */
|
||||
int mon_remainder = mon % 12;
|
||||
int negative_mon_remainder = mon_remainder < 0;
|
||||
int mon_years = mon / 12 - negative_mon_remainder;
|
||||
int year = year_requested + mon_years;
|
||||
|
||||
/* The other values need not be in range:
|
||||
the remaining code handles minor overflows correctly,
|
||||
assuming int and time_t arithmetic wraps around.
|
||||
Major overflows are caught at the end. */
|
||||
|
||||
/* Calculate day of year from year, month, and day of month.
|
||||
The result need not be in range. */
|
||||
int yday = ((__mon_yday[__isleap (year + TM_YEAR_BASE)]
|
||||
[mon_remainder + 12 * negative_mon_remainder])
|
||||
+ mday - 1);
|
||||
|
||||
#if LEAP_SECONDS_POSSIBLE
|
||||
/* Handle out-of-range seconds specially,
|
||||
since ydhms_tm_diff assumes every minute has 60 seconds. */
|
||||
int sec_requested = sec;
|
||||
if (sec < 0)
|
||||
sec = 0;
|
||||
if (59 < sec)
|
||||
sec = 59;
|
||||
#endif
|
||||
|
||||
/* Invert CONVERT by probing. First assume the same offset as last time.
|
||||
Then repeatedly use the error to improve the guess. */
|
||||
|
||||
tm.tm_year = EPOCH_YEAR - TM_YEAR_BASE;
|
||||
tm.tm_yday = tm.tm_hour = tm.tm_min = tm.tm_sec = 0;
|
||||
t0 = ydhms_tm_diff (year, yday, hour, min, sec, &tm);
|
||||
|
||||
for (t = t0 + *offset;
|
||||
(dt = ydhms_tm_diff (year, yday, hour, min, sec, (*convert) (&t, &tm)));
|
||||
t += dt)
|
||||
if (--remaining_probes == 0)
|
||||
return -1;
|
||||
|
||||
/* Check whether tm.tm_isdst has the requested value, if any. */
|
||||
if (0 <= isdst && 0 <= tm.tm_isdst)
|
||||
{
|
||||
int dst_diff = (isdst != 0) - (tm.tm_isdst != 0);
|
||||
if (dst_diff)
|
||||
{
|
||||
/* Move two hours in the direction indicated by the disagreement,
|
||||
probe some more, and switch to a new time if found.
|
||||
The largest known fallback due to daylight savings is two hours:
|
||||
once, in Newfoundland, 1988-10-30 02:00 -> 00:00. */
|
||||
time_t ot = t - 2 * 60 * 60 * dst_diff;
|
||||
while (--remaining_probes != 0)
|
||||
{
|
||||
struct tm otm;
|
||||
if (! (dt = ydhms_tm_diff (year, yday, hour, min, sec,
|
||||
(*convert) (&ot, &otm))))
|
||||
{
|
||||
t = ot;
|
||||
tm = otm;
|
||||
break;
|
||||
}
|
||||
if ((ot += dt) == t)
|
||||
break; /* Avoid a redundant probe. */
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
*offset = t - t0;
|
||||
|
||||
#if LEAP_SECONDS_POSSIBLE
|
||||
if (sec_requested != tm.tm_sec)
|
||||
{
|
||||
/* Adjust time to reflect the tm_sec requested, not the normalized value.
|
||||
Also, repair any damage from a false match due to a leap second. */
|
||||
t += sec_requested - sec + (sec == 0 && tm.tm_sec == 60);
|
||||
(*convert) (&t, &tm);
|
||||
}
|
||||
#endif
|
||||
|
||||
if (TIME_T_MAX / INT_MAX / 366 / 24 / 60 / 60 < 3)
|
||||
{
|
||||
/* time_t isn't large enough to rule out overflows in ydhms_tm_diff,
|
||||
so check for major overflows. A gross check suffices,
|
||||
since if t has overflowed, it is off by a multiple of
|
||||
TIME_T_MAX - TIME_T_MIN + 1. So ignore any component of
|
||||
the difference that is bounded by a small value. */
|
||||
|
||||
double dyear = (double) year_requested + mon_years - tm.tm_year;
|
||||
double dday = 366 * dyear + mday;
|
||||
double dsec = 60 * (60 * (24 * dday + hour) + min) + sec_requested;
|
||||
|
||||
if (TIME_T_MAX / 3 - TIME_T_MIN / 3 < (dsec < 0 ? - dsec : dsec))
|
||||
return -1;
|
||||
}
|
||||
|
||||
*tp = tm;
|
||||
return t;
|
||||
}
|
||||
|
||||
#ifdef weak_alias
|
||||
weak_alias (mktime, timelocal)
|
||||
#endif
|
||||
|
||||
#ifdef DEBUG
|
||||
void
|
||||
#if DEBUG
|
||||
|
||||
static int
|
||||
not_equal_tm (a, b)
|
||||
struct tm *a;
|
||||
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)
|
||||
| (a->tm_mday ^ b->tm_mday)
|
||||
| (a->tm_yday ^ b->tm_yday)
|
||||
| (a->tm_isdst ^ b->tm_isdst));
|
||||
}
|
||||
|
||||
static void
|
||||
print_tm (tp)
|
||||
struct tm *tp;
|
||||
{
|
||||
printf ("%04d-%02d-%02d %02d:%02d:%02d yday %03d wday %d isdst %d",
|
||||
tp->tm_year + TM_YEAR_BASE, tp->tm_mon + 1, tp->tm_mday,
|
||||
tp->tm_hour, tp->tm_min, tp->tm_sec,
|
||||
tp->tm_yday, tp->tm_wday, tp->tm_isdst);
|
||||
}
|
||||
|
||||
static int
|
||||
check_result (tk, tmk, tl, tml)
|
||||
time_t tk;
|
||||
struct tm tmk;
|
||||
time_t tl;
|
||||
struct tm tml;
|
||||
{
|
||||
if (tk != tl || not_equal_tm (&tmk, &tml))
|
||||
{
|
||||
printf ("mktime (");
|
||||
print_tm (&tmk);
|
||||
printf (")\nyields (");
|
||||
print_tm (&tml);
|
||||
printf (") == %ld, should be %ld\n", (long) tl, (long) tk);
|
||||
return 1;
|
||||
}
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
int
|
||||
main (argc, argv)
|
||||
int argc;
|
||||
char *argv[];
|
||||
char **argv;
|
||||
{
|
||||
int time;
|
||||
int result_time;
|
||||
struct tm *tmptr;
|
||||
|
||||
if (argc == 1)
|
||||
int status = 0;
|
||||
struct tm tm, tmk, tml;
|
||||
time_t tk, tl;
|
||||
char trailer;
|
||||
|
||||
if ((argc == 3 || argc == 4)
|
||||
&& (sscanf (argv[1], "%d-%d-%d%c",
|
||||
&tm.tm_year, &tm.tm_mon, &tm.tm_mday, &trailer)
|
||||
== 3)
|
||||
&& (sscanf (argv[2], "%d:%d:%d%c",
|
||||
&tm.tm_hour, &tm.tm_min, &tm.tm_sec, &trailer)
|
||||
== 3))
|
||||
{
|
||||
long q;
|
||||
|
||||
printf ("starting long test...\n");
|
||||
|
||||
for (q = 10000000; q < 1000000000; q += 599)
|
||||
{
|
||||
struct tm *tm = localtime ((time_t *) &q);
|
||||
if ((q % 10000) == 0) { printf ("%ld\n", q); fflush (stdout); }
|
||||
if (q != my_mktime (tm))
|
||||
{ printf ("failed for %ld\n", q); fflush (stdout); }
|
||||
}
|
||||
|
||||
printf ("test finished\n");
|
||||
|
||||
exit (0);
|
||||
tm.tm_year -= TM_YEAR_BASE;
|
||||
tm.tm_mon--;
|
||||
tm.tm_isdst = argc == 3 ? -1 : atoi (argv[3]);
|
||||
tmk = tm;
|
||||
tl = mktime (&tmk);
|
||||
tml = *localtime (&tl);
|
||||
printf ("mktime returns %ld == ", (long) tl);
|
||||
print_tm (&tmk);
|
||||
printf ("\n");
|
||||
status = check_result (tl, tmk, tl, tml);
|
||||
}
|
||||
|
||||
if (argc != 2)
|
||||
else if (argc == 4 || (argc == 5 && strcmp (argv[4], "-") == 0))
|
||||
{
|
||||
printf ("wrong # of args\n");
|
||||
exit (0);
|
||||
time_t from = atol (argv[1]);
|
||||
time_t by = atol (argv[2]);
|
||||
time_t to = atol (argv[3]);
|
||||
|
||||
if (argc == 4)
|
||||
for (tl = from; tl <= to; tl += by)
|
||||
{
|
||||
tml = *localtime (&tl);
|
||||
tmk = tml;
|
||||
tk = mktime (&tmk);
|
||||
status |= check_result (tk, tmk, tl, tml);
|
||||
}
|
||||
else
|
||||
for (tl = from; tl <= to; tl += by)
|
||||
{
|
||||
/* Null benchmark. */
|
||||
tml = *localtime (&tl);
|
||||
tmk = tml;
|
||||
tk = tl;
|
||||
status |= check_result (tk, tmk, tl, tml);
|
||||
}
|
||||
}
|
||||
|
||||
debugging_enabled = 1; /* We want to see the info */
|
||||
else
|
||||
printf ("Usage:\
|
||||
\t%s YYYY-MM-DD HH:MM:SS [ISDST] # Test given time.\n\
|
||||
\t%s FROM BY TO # Test values FROM, FROM+BY, ..., TO.\n\
|
||||
\t%s FROM BY TO - # Do not test those values (for benchmark).\n",
|
||||
argv[0], argv[0], argv[0]);
|
||||
|
||||
++argv;
|
||||
time = atoi (*argv);
|
||||
|
||||
tmptr = localtime ((time_t *) &time);
|
||||
printf ("Localtime tells us that a time_t of %d represents\n ", time);
|
||||
printtm (tmptr);
|
||||
putchar ('\n');
|
||||
|
||||
printf (" Given localtime's return val, mktime returns %d which is\n ",
|
||||
(int) my_mktime (tmptr));
|
||||
printtm (tmptr);
|
||||
putchar ('\n');
|
||||
|
||||
#if 0
|
||||
tmptr->tm_sec -= 20;
|
||||
tmptr->tm_min -= 20;
|
||||
tmptr->tm_hour -= 20;
|
||||
tmptr->tm_mday -= 20;
|
||||
tmptr->tm_mon -= 20;
|
||||
tmptr->tm_year -= 20;
|
||||
tmptr->tm_gmtoff -= 20000; /* This has no effect! */
|
||||
tmptr->tm_zone = NULL; /* Nor does this! */
|
||||
tmptr->tm_isdst = -1;
|
||||
#endif
|
||||
|
||||
tmptr->tm_hour += 1;
|
||||
tmptr->tm_isdst = -1;
|
||||
|
||||
printf ("\n\nchanged ranges: ");
|
||||
printtm (tmptr);
|
||||
putchar ('\n');
|
||||
|
||||
result_time = my_mktime (tmptr);
|
||||
printf ("\nmktime: %d\n", result_time);
|
||||
|
||||
tmptr->tm_isdst = 0;
|
||||
|
||||
printf ("\n\nchanged ranges: ");
|
||||
printtm (tmptr);
|
||||
putchar ('\n');
|
||||
|
||||
result_time = my_mktime (tmptr);
|
||||
printf ("\nmktime: %d\n", result_time);
|
||||
return status;
|
||||
}
|
||||
#endif /* DEBUG */
|
||||
|
||||
#endif /* DEBUG */
|
||||
|
||||
/*
|
||||
Local Variables:
|
||||
compile-command: "gcc -g mktime.c -o mktime -DDEBUG"
|
||||
compile-command: "gcc -DDEBUG=1 -Wall -O -g mktime.c -o mktime"
|
||||
End:
|
||||
*/
|
||||
|
||||
@ -21,7 +21,7 @@ Cambridge, MA 02139, USA. */
|
||||
|
||||
|
||||
/* Defined in mktime.c. */
|
||||
extern CONST unsigned short int __mon_lengths[2][12];
|
||||
extern CONST unsigned short int __mon_yday[2][13];
|
||||
|
||||
#define SECS_PER_HOUR (60 * 60)
|
||||
#define SECS_PER_DAY (SECS_PER_HOUR * 24)
|
||||
@ -71,10 +71,10 @@ DEFUN(__offtime, (t, offset, tp),
|
||||
}
|
||||
tp->tm_year = y - 1900;
|
||||
tp->tm_yday = days;
|
||||
ip = __mon_lengths[__isleap(y)];
|
||||
for (y = 0; days >= ip[y]; ++y)
|
||||
days -= ip[y];
|
||||
ip = __mon_yday[__isleap(y)];
|
||||
for (y = 11; days < ip[y]; --y)
|
||||
continue;
|
||||
days -= ip[y];
|
||||
tp->tm_mon = y;
|
||||
tp->tm_mday = days + 1;
|
||||
tp->tm_isdst = -1;
|
||||
}
|
||||
|
||||
@ -110,10 +110,11 @@ extern time_t mktime __P ((struct tm *__tp));
|
||||
|
||||
/* Subroutine of `mktime'. Return the `time_t' representation of TP and
|
||||
normalize TP, given that a `struct tm *' maps to a `time_t' as performed
|
||||
by FUNC. */
|
||||
by FUNC. Keep track of next guess for time_t offset in *OFFSET. */
|
||||
extern time_t __mktime_internal __P ((struct tm *__tp,
|
||||
struct tm *(*__func) (const time_t *,
|
||||
struct tm *)));
|
||||
struct tm *),
|
||||
time_t *__offset));
|
||||
|
||||
|
||||
/* Format TP into S according to FORMAT.
|
||||
|
||||
@ -22,6 +22,7 @@ time_t
|
||||
timegm (tmp)
|
||||
struct tm *const tmp;
|
||||
{
|
||||
static time_t gmtime_offset;
|
||||
tmp->tm_isdst = 0;
|
||||
return __mktime_internal (tmp, __gmtime_r);
|
||||
return __mktime_internal (tmp, __gmtime_r, &gmtime_offset);
|
||||
}
|
||||
|
||||
@ -25,7 +25,7 @@ Cambridge, MA 02139, USA. */
|
||||
#include <time.h>
|
||||
|
||||
/* Defined in mktime.c. */
|
||||
extern CONST unsigned short int __mon_lengths[2][12];
|
||||
extern CONST unsigned short int __mon_yday[2][13];
|
||||
|
||||
#define NOID
|
||||
#include "tzfile.h"
|
||||
@ -403,10 +403,11 @@ DEFUN(compute_change, (rule, year), tz_rule *rule AND int year)
|
||||
/* Mm.n.d - Nth "Dth day" of month M. */
|
||||
{
|
||||
register int i, d, m1, yy0, yy1, yy2, dow;
|
||||
register CONST unsigned short int *myday =
|
||||
&__mon_yday[__isleap (year)][rule->m];
|
||||
|
||||
/* First add SECSPERDAY for each day in months before M. */
|
||||
for (i = 0; i < rule->m - 1; ++i)
|
||||
t += __mon_lengths[__isleap (year)][i] * SECSPERDAY;
|
||||
t += myday[-1] * SECSPERDAY;
|
||||
|
||||
/* Use Zeller's Congruence to get day-of-week of first day of month. */
|
||||
m1 = (rule->m + 9) % 12 + 1;
|
||||
@ -424,7 +425,7 @@ DEFUN(compute_change, (rule, year), tz_rule *rule AND int year)
|
||||
d += 7;
|
||||
for (i = 1; i < rule->n; ++i)
|
||||
{
|
||||
if (d + 7 >= __mon_lengths[__isleap (year)][rule->m - 1])
|
||||
if (d + 7 >= myday[0] - myday[-1])
|
||||
break;
|
||||
d += 7;
|
||||
}
|
||||
|
||||
Loading…
Reference in New Issue
Block a user