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[Emacs-diffs] master 3707f60: Sync from gnulib
|
From: |
Paul Eggert |
|
Subject: |
[Emacs-diffs] master 3707f60: Sync from gnulib |
|
Date: |
Mon, 02 May 2016 01:37:07 +0000 |
branch: master
commit 3707f609cb8017371610a5e2233bd8478416217c
Author: Paul Eggert <address@hidden>
Commit: Paul Eggert <address@hidden>
Sync from gnulib
This incorporates:
2016-05-01 mktime: port to stricter signed overflow checking
2016-05-01 mktime: speed up DEBUG_MKTIME benchmarks
2016-05-01 mktime: resurrect DEBUG_MKTIME testing
2016-05-01 mktime: simplify DEBUG_MKTIME
2016-05-01 Port mktime_internal offset to unsigned time_t
2016-04-27 xstrtol: prohibit monstrosities like "1bB"
2016-04-13 mktime: improve integer overflow checking
2016-04-13 intprops: check two's complement assumption
2016-04-13 intprops, mktime, strtol: assume two's complement
* lib/intprops.h, lib/mktime-internal.h, lib/mktime.c:
* lib/strtol.c, lib/timegm.c, m4/mktime.m4, m4/std-gnu11.m4:
Copy from gnulib.
---
lib/intprops.h | 45 +++--
lib/mktime-internal.h | 35 +++-
lib/mktime.c | 461 +++++++++++++++++++------------------------------
lib/strtol.c | 31 ++--
lib/timegm.c | 6 +-
m4/mktime.m4 | 22 ++-
m4/std-gnu11.m4 | 8 +-
7 files changed, 266 insertions(+), 342 deletions(-)
diff --git a/lib/intprops.h b/lib/intprops.h
index a278497..3152139 100644
--- a/lib/intprops.h
+++ b/lib/intprops.h
@@ -21,6 +21,7 @@
#define _GL_INTPROPS_H
#include <limits.h>
+#include <verify.h>
/* Return a value with the common real type of E and V and the value of V. */
#define _GL_INT_CONVERT(e, v) (0 * (e) + (v))
@@ -36,17 +37,6 @@
an integer. */
#define TYPE_IS_INTEGER(t) ((t) 1.5 == 1)
-/* True if negative values of the signed integer type T use two's
- complement, ones' complement, or signed magnitude representation,
- respectively. Much GNU code assumes two's complement, but some
- people like to be portable to all possible C hosts. */
-#define TYPE_TWOS_COMPLEMENT(t) ((t) ~ (t) 0 == (t) -1)
-#define TYPE_ONES_COMPLEMENT(t) ((t) ~ (t) 0 == 0)
-#define TYPE_SIGNED_MAGNITUDE(t) ((t) ~ (t) 0 < (t) -1)
-
-/* True if the signed integer expression E uses two's complement. */
-#define _GL_INT_TWOS_COMPLEMENT(e) (~ _GL_INT_CONVERT (e, 0) == -1)
-
/* True if the real type T is signed. */
#define TYPE_SIGNED(t) (! ((t) 0 < (t) -1))
@@ -55,18 +45,10 @@
#define EXPR_SIGNED(e) (_GL_INT_NEGATE_CONVERT (e, 1) < 0)
-/* Minimum and maximum values for integer types and expressions. These
- macros have undefined behavior if T is signed and has padding bits.
- If this is a problem for you, please let us know how to fix it for
- your host. */
+/* Minimum and maximum values for integer types and expressions. */
/* The maximum and minimum values for the integer type T. */
-#define TYPE_MINIMUM(t) \
- ((t) (! TYPE_SIGNED (t) \
- ? (t) 0 \
- : TYPE_SIGNED_MAGNITUDE (t) \
- ? ~ (t) 0 \
- : ~ TYPE_MAXIMUM (t)))
+#define TYPE_MINIMUM(t) ((t) ~ TYPE_MAXIMUM (t))
#define TYPE_MAXIMUM(t) \
((t) (! TYPE_SIGNED (t) \
? (t) -1 \
@@ -76,7 +58,7 @@
after integer promotion. E should not have side effects. */
#define _GL_INT_MINIMUM(e) \
(EXPR_SIGNED (e) \
- ? - _GL_INT_TWOS_COMPLEMENT (e) - _GL_SIGNED_INT_MAXIMUM (e) \
+ ? ~ _GL_SIGNED_INT_MAXIMUM (e) \
: _GL_INT_CONVERT (e, 0))
#define _GL_INT_MAXIMUM(e) \
(EXPR_SIGNED (e) \
@@ -85,8 +67,25 @@
#define _GL_SIGNED_INT_MAXIMUM(e) \
(((_GL_INT_CONVERT (e, 1) << (sizeof ((e) + 0) * CHAR_BIT - 2)) - 1) * 2 + 1)
+/* This include file assumes that signed types are two's complement without
+ padding bits; the above macros have undefined behavior otherwise.
+ If this is a problem for you, please let us know how to fix it for your
host.
+ As a sanity check, test the assumption for some signed types that
+ <limits.h> bounds. */
+verify (TYPE_MINIMUM (signed char) == SCHAR_MIN);
+verify (TYPE_MAXIMUM (signed char) == SCHAR_MAX);
+verify (TYPE_MINIMUM (short int) == SHRT_MIN);
+verify (TYPE_MAXIMUM (short int) == SHRT_MAX);
+verify (TYPE_MINIMUM (int) == INT_MIN);
+verify (TYPE_MAXIMUM (int) == INT_MAX);
+verify (TYPE_MINIMUM (long int) == LONG_MIN);
+verify (TYPE_MAXIMUM (long int) == LONG_MAX);
+#ifdef LLONG_MAX
+verify (TYPE_MINIMUM (long long int) == LLONG_MIN);
+verify (TYPE_MAXIMUM (long long int) == LLONG_MAX);
+#endif
-/* Return 1 if the __typeof__ keyword works. This could be done by
+/* Does the __typeof__ keyword work? This could be done by
'configure', but for now it's easier to do it by hand. */
#if (2 <= __GNUC__ || defined __IBM__TYPEOF__ \
|| (0x5110 <= __SUNPRO_C && !__STDC__))
diff --git a/lib/mktime-internal.h b/lib/mktime-internal.h
index 4287acf..2f586ae 100644
--- a/lib/mktime-internal.h
+++ b/lib/mktime-internal.h
@@ -1,4 +1,37 @@
+/* mktime variant that also uses an offset guess
+
+ Copyright 2016 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 3 of the License, 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/>. */
+
#include <time.h>
+
+/* mktime_offset_t is a signed type wide enough to hold a UTC offset
+ in seconds, and used as part of the type of the offset-guess
+ argument to mktime_internal. Use time_t on platforms where time_t
+ is signed, to be compatible with platforms like BeOS that export
+ this implementation detail of mktime. On platforms where time_t is
+ unsigned, GNU and POSIX code can assume 'int' is at least 32 bits
+ which is wide enough for a UTC offset. */
+
+#if TIME_T_IS_SIGNED
+typedef time_t mktime_offset_t;
+#else
+typedef int mktime_offset_t;
+#endif
+
time_t mktime_internal (struct tm *,
struct tm * (*) (time_t const *, struct tm *),
- time_t *);
+ mktime_offset_t *);
diff --git a/lib/mktime.c b/lib/mktime.c
index c9738d0..419a177 100644
--- a/lib/mktime.c
+++ b/lib/mktime.c
@@ -17,11 +17,13 @@
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
-/* Define this to have a standalone program to test this implementation of
+/* Define this to 1 to have a standalone program to test this implementation of
mktime. */
-/* #define DEBUG_MKTIME 1 */
+#ifndef DEBUG_MKTIME
+# define DEBUG_MKTIME 0
+#endif
-#ifndef _LIBC
+#if !defined _LIBC && !DEBUG_MKTIME
# include <config.h>
#endif
@@ -35,114 +37,76 @@
#include <time.h>
#include <limits.h>
+#include <stdbool.h>
-#include <string.h> /* For the real memcpy prototype. */
+#include <intprops.h>
+#include <verify.h>
-#if defined DEBUG_MKTIME && DEBUG_MKTIME
+#if DEBUG_MKTIME
# include <stdio.h>
# include <stdlib.h>
+# include <string.h>
/* Make it work even if the system's libc has its own mktime routine. */
# undef mktime
# define mktime my_mktime
-#endif /* DEBUG_MKTIME */
-
-/* Some of the code in this file assumes that signed integer overflow
- silently wraps around. This assumption can't easily be programmed
- around, nor can it be checked for portably at compile-time or
- easily eliminated at run-time.
-
- Define WRAPV to 1 if the assumption is valid and if
- #pragma GCC optimize ("wrapv")
- does not trigger GCC bug 51793
- <http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51793>.
- Otherwise, define it to 0; this forces the use of slower code that,
- while not guaranteed by the C Standard, works on all production
- platforms that we know about. */
-#ifndef WRAPV
-# if (((__GNUC__ == 4 && 4 <= __GNUC_MINOR__) || 4 < __GNUC__) \
- && defined __GLIBC__)
-# pragma GCC optimize ("wrapv")
-# define WRAPV 1
-# else
-# define WRAPV 0
-# endif
#endif
-/* Verify a requirement at compile-time (unlike assert, which is runtime). */
-#define verify(name, assertion) struct name { char a[(assertion) ? 1 : -1]; }
+/* A signed type that can represent an integer number of years
+ multiplied by three times the number of seconds in a year. It is
+ needed when converting a tm_year value times the number of seconds
+ in a year. The factor of three comes because these products need
+ to be subtracted from each other, and sometimes with an offset
+ added to them, without worrying about overflow.
-/* A signed type that is at least one bit wider than int. */
-#if INT_MAX <= LONG_MAX / 2
+ Much of the code uses long_int to represent time_t values, to
+ lessen the hassle of dealing with platforms where time_t is
+ unsigned, and because long_int should suffice to represent all
+ time_t values that mktime can generate even on platforms where
+ time_t is excessively wide. */
+
+#if INT_MAX <= LONG_MAX / 3 / 366 / 24 / 60 / 60
typedef long int long_int;
#else
typedef long long int long_int;
#endif
-verify (long_int_is_wide_enough, INT_MAX == INT_MAX * (long_int) 2 / 2);
+verify (INT_MAX <= TYPE_MAXIMUM (long_int) / 3 / 366 / 24 / 60 / 60);
/* Shift A right by B bits portably, by dividing A by 2**B and
- truncating towards minus infinity. A and B should be free of side
- effects, and B should be in the range 0 <= B <= INT_BITS - 2, where
- INT_BITS is the number of useful bits in an int. GNU code can
- assume that INT_BITS is at least 32.
+ truncating towards minus infinity. B should be in the range 0 <= B
+ <= LONG_INT_BITS - 2, where LONG_INT_BITS is the number of useful
+ bits in a long_int. LONG_INT_BITS is at least 32.
ISO C99 says that A >> B is implementation-defined if A < 0. Some
implementations (e.g., UNICOS 9.0 on a Cray Y-MP EL) don't shift
right in the usual way when A < 0, so SHR falls back on division if
ordinary A >> B doesn't seem to be the usual signed shift. */
-#define SHR(a, b) \
- ((-1 >> 1 == -1 \
- && (long_int) -1 >> 1 == -1 \
- && ((time_t) -1 >> 1 == -1 || ! TYPE_SIGNED (time_t))) \
- ? (a) >> (b) \
- : (a) / (1 << (b)) - ((a) % (1 << (b)) < 0))
-
-/* The extra casts in the following macros work around compiler bugs,
- e.g., in Cray C 5.0.3.0. */
-
-/* True if the arithmetic type T is an integer type. bool counts as
- an integer. */
-#define TYPE_IS_INTEGER(t) ((t) 1.5 == 1)
-
-/* True if negative values of the signed integer type T use two's
- complement, or if T is an unsigned integer type. */
-#define TYPE_TWOS_COMPLEMENT(t) ((t) ~ (t) 0 == (t) -1)
-
-/* True if the arithmetic type T is signed. */
-#define TYPE_SIGNED(t) (! ((t) 0 < (t) -1))
-
-/* The maximum and minimum values for the integer type T. These
- macros have undefined behavior if T is signed and has padding bits.
- If this is a problem for you, please let us know how to fix it for
- your host. */
-#define TYPE_MINIMUM(t) \
- ((t) (! TYPE_SIGNED (t) \
- ? (t) 0 \
- : ~ TYPE_MAXIMUM (t)))
-#define TYPE_MAXIMUM(t) \
- ((t) (! TYPE_SIGNED (t) \
- ? (t) -1 \
- : ((((t) 1 << (sizeof (t) * CHAR_BIT - 2)) - 1) * 2 + 1)))
-
-#ifndef TIME_T_MIN
-# define TIME_T_MIN TYPE_MINIMUM (time_t)
-#endif
-#ifndef TIME_T_MAX
-# define TIME_T_MAX TYPE_MAXIMUM (time_t)
-#endif
-#define TIME_T_MIDPOINT (SHR (TIME_T_MIN + TIME_T_MAX, 1) + 1)
-verify (time_t_is_integer, TYPE_IS_INTEGER (time_t));
-verify (twos_complement_arithmetic,
- (TYPE_TWOS_COMPLEMENT (int)
- && TYPE_TWOS_COMPLEMENT (long_int)
- && TYPE_TWOS_COMPLEMENT (time_t)));
+static long_int
+shr (long_int a, int b)
+{
+ long_int one = 1;
+ return (-one >> 1 == -1
+ ? a >> b
+ : a / (one << b) - (a % (one << b) < 0));
+}
+
+/* Bounds for the intersection of time_t and long_int. */
+
+static long_int const mktime_min
+ = ((TYPE_SIGNED (time_t) && TYPE_MINIMUM (time_t) < TYPE_MINIMUM (long_int))
+ ? TYPE_MINIMUM (long_int) : TYPE_MINIMUM (time_t));
+static long_int const mktime_max
+ = (TYPE_MAXIMUM (long_int) < TYPE_MAXIMUM (time_t)
+ ? TYPE_MAXIMUM (long_int) : TYPE_MAXIMUM (time_t));
+
+verify (TYPE_IS_INTEGER (time_t));
#define EPOCH_YEAR 1970
#define TM_YEAR_BASE 1900
-verify (base_year_is_a_multiple_of_100, TM_YEAR_BASE % 100 == 0);
+verify (TM_YEAR_BASE % 100 == 0);
-/* Return 1 if YEAR + TM_YEAR_BASE is a leap year. */
-static int
+/* Is YEAR + TM_YEAR_BASE a leap year? */
+static bool
leapyear (long_int year)
{
/* Don't add YEAR to TM_YEAR_BASE, as that might overflow.
@@ -166,7 +130,9 @@ const unsigned short int __mon_yday[2][13] =
};
-#ifndef _LIBC
+#ifdef _LIBC
+typedef time_t mktime_offset_t;
+#else
/* Portable standalone applications should supply a <time.h> that
declares a POSIX-compliant localtime_r, for the benefit of older
implementations that lack localtime_r or have a nonstandard one.
@@ -177,9 +143,9 @@ const unsigned short int __mon_yday[2][13] =
# include "mktime-internal.h"
#endif
-/* Return 1 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 int
+/* Do 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);
@@ -190,104 +156,65 @@ isdst_differ (int a, int b)
were not adjusted between the time stamps.
The YEAR values uses the same numbering as TP->tm_year. Values
- need not be in the usual range. However, YEAR1 must not be less
- than 2 * INT_MIN or greater than 2 * INT_MAX.
+ need not be in the usual range. However, YEAR1 must not overflow
+ when multiplied by three times the number of seconds in a year, and
+ likewise for YDAY1 and three times the number of seconds in a day. */
- The result may overflow. It is the caller's responsibility to
- detect overflow. */
-
-static time_t
+static long_int
ydhms_diff (long_int year1, long_int yday1, int hour1, int min1, int sec1,
int year0, int yday0, int hour0, int min0, int sec0)
{
- verify (C99_integer_division, -1 / 2 == 0);
+ verify (-1 / 2 == 0);
/* Compute intervening leap days correctly even if year is negative.
Take care to avoid integer overflow here. */
- int a4 = SHR (year1, 2) + SHR (TM_YEAR_BASE, 2) - ! (year1 & 3);
- int b4 = SHR (year0, 2) + SHR (TM_YEAR_BASE, 2) - ! (year0 & 3);
+ int a4 = shr (year1, 2) + shr (TM_YEAR_BASE, 2) - ! (year1 & 3);
+ int b4 = shr (year0, 2) + shr (TM_YEAR_BASE, 2) - ! (year0 & 3);
int a100 = a4 / 25 - (a4 % 25 < 0);
int b100 = b4 / 25 - (b4 % 25 < 0);
- int a400 = SHR (a100, 2);
- int b400 = SHR (b100, 2);
+ int a400 = shr (a100, 2);
+ int b400 = shr (b100, 2);
int intervening_leap_days = (a4 - b4) - (a100 - b100) + (a400 - b400);
- /* Compute the desired time in time_t precision. Overflow might
- occur here. */
- time_t tyear1 = year1;
- time_t years = tyear1 - year0;
- time_t days = 365 * years + yday1 - yday0 + intervening_leap_days;
- time_t hours = 24 * days + hour1 - hour0;
- time_t minutes = 60 * hours + min1 - min0;
- time_t seconds = 60 * minutes + sec1 - sec0;
+ /* Compute the desired time without overflowing. */
+ long_int years = year1 - year0;
+ long_int days = 365 * years + yday1 - yday0 + intervening_leap_days;
+ long_int hours = 24 * days + hour1 - hour0;
+ long_int minutes = 60 * hours + min1 - min0;
+ long_int seconds = 60 * minutes + sec1 - sec0;
return seconds;
}
-/* Return the average of A and B, even if A + B would overflow. */
-static time_t
-time_t_avg (time_t a, time_t b)
+/* Return the average of A and B, even if A + B would overflow.
+ Round toward positive infinity. */
+static long_int
+long_int_avg (long_int a, long_int b)
{
- return SHR (a, 1) + SHR (b, 1) + (a & b & 1);
-}
-
-/* Return 1 if A + B does not overflow. If time_t is unsigned and if
- B's top bit is set, assume that the sum represents A - -B, and
- return 1 if the subtraction does not wrap around. */
-static int
-time_t_add_ok (time_t a, time_t b)
-{
- if (! TYPE_SIGNED (time_t))
- {
- time_t sum = a + b;
- return (sum < a) == (TIME_T_MIDPOINT <= b);
- }
- else if (WRAPV)
- {
- time_t sum = a + b;
- return (sum < a) == (b < 0);
- }
- else
- {
- time_t avg = time_t_avg (a, b);
- return TIME_T_MIN / 2 <= avg && avg <= TIME_T_MAX / 2;
- }
-}
-
-/* Return 1 if A + B does not overflow. */
-static int
-time_t_int_add_ok (time_t a, int b)
-{
- verify (int_no_wider_than_time_t, INT_MAX <= TIME_T_MAX);
- if (WRAPV)
- {
- time_t sum = a + b;
- return (sum < a) == (b < 0);
- }
- else
- {
- int a_odd = a & 1;
- time_t avg = SHR (a, 1) + (SHR (b, 1) + (a_odd & b));
- return TIME_T_MIN / 2 <= avg && avg <= TIME_T_MAX / 2;
- }
+ return shr (a, 1) + shr (b, 1) + ((a | b) & 1);
}
/* Return a time_t value corresponding to (YEAR-YDAY HOUR:MIN:SEC),
- assuming that *T corresponds to *TP and that no clock adjustments
+ assuming that T corresponds to *TP and that no clock adjustments
occurred between *TP and the desired time.
- If TP is null, return a value not equal to *T; this avoids false matches.
- If overflow occurs, yield the minimal or maximal value, except do not
- yield a value equal to *T. */
-static time_t
+ Although T and the returned value are of type long_int,
+ they represent time_t values and must be in time_t range.
+ If TP is null, return a value not equal to T; this avoids false matches.
+ YEAR and YDAY must not be so large that multiplying them by three times the
+ number of seconds in a year (or day, respectively) would overflow long_int.
+ If the returned value would be out of range, yield the minimal or
+ maximal in-range value, except do not yield a value equal to T. */
+static long_int
guess_time_tm (long_int year, long_int yday, int hour, int min, int sec,
- const time_t *t, const struct tm *tp)
+ long_int t, const struct tm *tp)
{
if (tp)
{
- time_t d = ydhms_diff (year, yday, hour, min, sec,
- tp->tm_year, tp->tm_yday,
- tp->tm_hour, tp->tm_min, tp->tm_sec);
- if (time_t_add_ok (*t, d))
- return *t + d;
+ long_int result;
+ long_int d = ydhms_diff (year, yday, hour, min, sec,
+ tp->tm_year, tp->tm_yday,
+ tp->tm_hour, tp->tm_min, tp->tm_sec);
+ if (! INT_ADD_WRAPV (t, d, &result))
+ return result;
}
/* Overflow occurred one way or another. Return the nearest result
@@ -295,32 +222,51 @@ guess_time_tm (long_int year, long_int yday, int hour,
int min, int sec,
if the actual difference is nonzero, as that would cause a false
match; and don't oscillate between two values, as that would
confuse the spring-forward gap detector. */
- return (*t < TIME_T_MIDPOINT
- ? (*t <= TIME_T_MIN + 1 ? *t + 1 : TIME_T_MIN)
- : (TIME_T_MAX - 1 <= *t ? *t - 1 : TIME_T_MAX));
+ return (t < long_int_avg (mktime_min, mktime_max)
+ ? (t <= mktime_min + 1 ? t + 1 : mktime_min)
+ : (mktime_max - 1 <= t ? t - 1 : mktime_max));
+}
+
+/* Use CONVERT to convert T to a struct tm value in *TM. T must be in
+ range for time_t. Return TM if successfull, NULL if T is out of
+ range for CONVERT. */
+static struct tm *
+convert_time (struct tm *(*convert) (const time_t *, struct tm *),
+ long_int t, struct tm *tm)
+{
+ time_t x = t;
+ return convert (&x, tm);
}
/* Use CONVERT to convert *T to a broken down time in *TP.
If *T is out of range for conversion, adjust it so that
- it is the nearest in-range value and then convert that. */
+ it is the nearest in-range value and then convert that.
+ A value is in range if it fits in both time_t and long_int. */
static struct tm *
ranged_convert (struct tm *(*convert) (const time_t *, struct tm *),
- time_t *t, struct tm *tp)
+ long_int *t, struct tm *tp)
{
- struct tm *r = convert (t, tp);
+ struct tm *r;
+ if (*t < mktime_min)
+ *t = mktime_min;
+ else if (mktime_max < *t)
+ *t = mktime_max;
+ r = convert_time (convert, *t, tp);
if (!r && *t)
{
- time_t bad = *t;
- time_t ok = 0;
+ long_int bad = *t;
+ long_int ok = 0;
- /* BAD is a known unconvertible time_t, and OK is a known good one.
+ /* BAD is a known unconvertible value, and OK is a known good one.
Use binary search to narrow the range between BAD and OK until
they differ by 1. */
- while (bad != ok + (bad < 0 ? -1 : 1))
+ while (true)
{
- time_t mid = *t = time_t_avg (ok, bad);
- r = convert (t, tp);
+ long_int mid = long_int_avg (ok, bad);
+ if (mid != ok && mid != bad)
+ break;
+ r = convert_time (convert, mid, tp);
if (r)
ok = mid;
else
@@ -331,15 +277,13 @@ ranged_convert (struct tm *(*convert) (const time_t *,
struct tm *),
{
/* The last conversion attempt failed;
revert to the most recent successful attempt. */
- *t = ok;
- r = convert (t, tp);
+ r = convert_time (convert, ok, tp);
}
}
return r;
}
-
/* 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,
@@ -349,9 +293,9 @@ ranged_convert (struct tm *(*convert) (const time_t *,
struct tm *),
time_t
__mktime_internal (struct tm *tp,
struct tm *(*convert) (const time_t *, struct tm *),
- time_t *offset)
+ mktime_offset_t *offset)
{
- time_t t, gt, t0, t1, t2;
+ long_int t, gt, t0, t1, t2, dt;
struct tm tm;
/* The maximum number of probes (calls to CONVERT) should be enough
@@ -381,9 +325,7 @@ __mktime_internal (struct tm *tp,
long_int year = lyear_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. */
+ the remaining code handles overflows correctly. */
/* Calculate day of year from year, month, and day of month.
The result need not be in range. */
@@ -393,7 +335,7 @@ __mktime_internal (struct tm *tp,
long_int lmday = mday;
long_int yday = mon_yday + lmday;
- time_t guessed_offset = *offset;
+ int negative_offset_guess;
int sec_requested = sec;
@@ -410,71 +352,14 @@ __mktime_internal (struct tm *tp,
/* Invert CONVERT by probing. First assume the same offset as last
time. */
+ INT_SUBTRACT_WRAPV (0, *offset, &negative_offset_guess);
t0 = ydhms_diff (year, yday, hour, min, sec,
- EPOCH_YEAR - TM_YEAR_BASE, 0, 0, 0, - guessed_offset);
-
- if (TIME_T_MAX / INT_MAX / 366 / 24 / 60 / 60 < 3)
- {
- /* time_t isn't large enough to rule out overflows, so check
- for major overflows. A gross check suffices, since if t0
- 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. */
-
- /* Approximate log base 2 of the number of time units per
- biennium. A biennium is 2 years; use this unit instead of
- years to avoid integer overflow. For example, 2 average
- Gregorian years are 2 * 365.2425 * 24 * 60 * 60 seconds,
- which is 63113904 seconds, and rint (log2 (63113904)) is
- 26. */
- int ALOG2_SECONDS_PER_BIENNIUM = 26;
- int ALOG2_MINUTES_PER_BIENNIUM = 20;
- int ALOG2_HOURS_PER_BIENNIUM = 14;
- int ALOG2_DAYS_PER_BIENNIUM = 10;
- int LOG2_YEARS_PER_BIENNIUM = 1;
-
- int approx_requested_biennia =
- (SHR (year_requested, LOG2_YEARS_PER_BIENNIUM)
- - SHR (EPOCH_YEAR - TM_YEAR_BASE, LOG2_YEARS_PER_BIENNIUM)
- + SHR (mday, ALOG2_DAYS_PER_BIENNIUM)
- + SHR (hour, ALOG2_HOURS_PER_BIENNIUM)
- + SHR (min, ALOG2_MINUTES_PER_BIENNIUM)
- + (LEAP_SECONDS_POSSIBLE
- ? 0
- : SHR (sec, ALOG2_SECONDS_PER_BIENNIUM)));
-
- int approx_biennia = SHR (t0, ALOG2_SECONDS_PER_BIENNIUM);
- int diff = approx_biennia - approx_requested_biennia;
- int approx_abs_diff = diff < 0 ? -1 - diff : diff;
-
- /* IRIX 4.0.5 cc miscalculates TIME_T_MIN / 3: it erroneously
- gives a positive value of 715827882. Setting a variable
- first then doing math on it seems to work.
- (address@hidden) */
- time_t time_t_max = TIME_T_MAX;
- time_t time_t_min = TIME_T_MIN;
- time_t overflow_threshold =
- (time_t_max / 3 - time_t_min / 3) >> ALOG2_SECONDS_PER_BIENNIUM;
-
- if (overflow_threshold < approx_abs_diff)
- {
- /* Overflow occurred. Try repairing it; this might work if
- the time zone offset is enough to undo the overflow. */
- time_t repaired_t0 = -1 - t0;
- approx_biennia = SHR (repaired_t0, ALOG2_SECONDS_PER_BIENNIUM);
- diff = approx_biennia - approx_requested_biennia;
- approx_abs_diff = diff < 0 ? -1 - diff : diff;
- if (overflow_threshold < approx_abs_diff)
- return -1;
- guessed_offset += repaired_t0 - t0;
- t0 = repaired_t0;
- }
- }
+ EPOCH_YEAR - TM_YEAR_BASE, 0, 0, 0, negative_offset_guess);
/* Repeatedly use the error to improve the guess. */
for (t = t1 = t2 = t0, dst2 = 0;
- (gt = guess_time_tm (year, yday, hour, min, sec, &t,
+ (gt = guess_time_tm (year, yday, hour, min, sec, t,
ranged_convert (convert, &t, &tm)),
t != gt);
t1 = t2, t2 = t, t = gt, dst2 = tm.tm_isdst != 0)
@@ -531,39 +416,42 @@ __mktime_internal (struct tm *tp,
for (delta = stride; delta < delta_bound; delta += stride)
for (direction = -1; direction <= 1; direction += 2)
- if (time_t_int_add_ok (t, delta * direction))
- {
- time_t ot = t + delta * direction;
- struct tm otm;
- ranged_convert (convert, &ot, &otm);
- if (! isdst_differ (isdst, otm.tm_isdst))
- {
- /* We found the desired tm_isdst.
- Extrapolate back to the desired time. */
- t = guess_time_tm (year, yday, hour, min, sec, &ot, &otm);
- ranged_convert (convert, &t, &tm);
- goto offset_found;
- }
- }
+ {
+ long_int ot;
+ if (! INT_ADD_WRAPV (t, delta * direction, &ot))
+ {
+ struct tm otm;
+ ranged_convert (convert, &ot, &otm);
+ if (! isdst_differ (isdst, otm.tm_isdst))
+ {
+ /* We found the desired tm_isdst.
+ Extrapolate back to the desired time. */
+ t = guess_time_tm (year, yday, hour, min, sec, ot, &otm);
+ ranged_convert (convert, &t, &tm);
+ goto offset_found;
+ }
+ }
+ }
}
offset_found:
- *offset = guessed_offset + t - t0;
+ /* Set *OFFSET to the low-order bits of T - T0 - NEGATIVE_OFFSET_GUESS.
+ This is just a heuristic to speed up the next mktime call, and
+ correctness is unaffected if integer overflow occurs here. */
+ INT_SUBTRACT_WRAPV (t, t0, &dt);
+ INT_SUBTRACT_WRAPV (dt, negative_offset_guess, offset);
if (LEAP_SECONDS_POSSIBLE && 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. */
- int sec_adjustment = (sec == 0 && tm.tm_sec == 60) - sec;
- if (! time_t_int_add_ok (t, sec_requested))
+ long_int sec_adjustment = sec == 0 && tm.tm_sec == 60;
+ sec_adjustment -= sec;
+ sec_adjustment += sec_requested;
+ if (INT_ADD_WRAPV (t, sec_adjustment, &t)
+ || ! (mktime_min <= t && t <= mktime_max)
+ || ! convert_time (convert, t, &tm))
return -1;
- t1 = t + sec_requested;
- if (! time_t_int_add_ok (t1, sec_adjustment))
- return -1;
- t2 = t1 + sec_adjustment;
- if (! convert (&t2, &tm))
- return -1;
- t = t2;
}
*tp = tm;
@@ -571,11 +459,7 @@ __mktime_internal (struct tm *tp,
}
-/* FIXME: This should use a signed type wide enough to hold any UTC
- offset in seconds. 'int' should be good enough for GNU code. We
- can't fix this unilaterally though, as other modules invoke
- __mktime_internal. */
-static time_t localtime_offset;
+static mktime_offset_t localtime_offset;
/* Convert *TP to a time_t value. */
time_t
@@ -600,7 +484,7 @@ libc_hidden_def (mktime)
libc_hidden_weak (timelocal)
#endif
-#if defined DEBUG_MKTIME && DEBUG_MKTIME
+#if DEBUG_MKTIME
static int
not_equal_tm (const struct tm *a, const struct tm *b)
@@ -652,6 +536,14 @@ main (int argc, char **argv)
time_t tk, tl, tl1;
char trailer;
+ /* Sanity check, plus call tzset. */
+ tl = 0;
+ if (! localtime (&tl))
+ {
+ printf ("localtime (0) fails\n");
+ status = 1;
+ }
+
if ((argc == 3 || argc == 4)
&& (sscanf (argv[1], "%d-%d-%d%c",
&tm.tm_year, &tm.tm_mon, &tm.tm_mday, &trailer)
@@ -665,12 +557,7 @@ main (int argc, char **argv)
tm.tm_isdst = argc == 3 ? -1 : atoi (argv[3]);
tmk = tm;
tl = mktime (&tmk);
- lt = localtime (&tl);
- if (lt)
- {
- tml = *lt;
- lt = &tml;
- }
+ lt = localtime_r (&tl, &tml);
printf ("mktime returns %ld == ", (long int) tl);
print_tm (&tmk);
printf ("\n");
@@ -685,16 +572,16 @@ main (int argc, char **argv)
if (argc == 4)
for (tl = from; by < 0 ? to <= tl : tl <= to; tl = tl1)
{
- lt = localtime (&tl);
+ lt = localtime_r (&tl, &tml);
if (lt)
{
- tmk = tml = *lt;
+ tmk = tml;
tk = mktime (&tmk);
status |= check_result (tk, tmk, tl, &tml);
}
else
{
- printf ("localtime (%ld) yields 0\n", (long int) tl);
+ printf ("localtime_r (%ld) yields 0\n", (long int) tl);
status = 1;
}
tl1 = tl + by;
@@ -705,16 +592,16 @@ main (int argc, char **argv)
for (tl = from; by < 0 ? to <= tl : tl <= to; tl = tl1)
{
/* Null benchmark. */
- lt = localtime (&tl);
+ lt = localtime_r (&tl, &tml);
if (lt)
{
- tmk = tml = *lt;
+ tmk = tml;
tk = tl;
status |= check_result (tk, tmk, tl, &tml);
}
else
{
- printf ("localtime (%ld) yields 0\n", (long int) tl);
+ printf ("localtime_r (%ld) yields 0\n", (long int) tl);
status = 1;
}
tl1 = tl + by;
diff --git a/lib/strtol.c b/lib/strtol.c
index b0215fc..6ef8a96 100644
--- a/lib/strtol.c
+++ b/lib/strtol.c
@@ -121,30 +121,19 @@
/* The extra casts in the following macros work around compiler bugs,
e.g., in Cray C 5.0.3.0. */
-/* True if negative values of the signed integer type T use two's
- complement, ones' complement, or signed magnitude representation,
- respectively. Much GNU code assumes two's complement, but some
- people like to be portable to all possible C hosts. */
-# define TYPE_TWOS_COMPLEMENT(t) ((t) ~ (t) 0 == (t) -1)
-# define TYPE_ONES_COMPLEMENT(t) ((t) ~ (t) 0 == 0)
-# define TYPE_SIGNED_MAGNITUDE(t) ((t) ~ (t) 0 < (t) -1)
-
/* True if the arithmetic type T is signed. */
# define TYPE_SIGNED(t) (! ((t) 0 < (t) -1))
-/* The maximum and minimum values for the integer type T. These
- macros have undefined behavior if T is signed and has padding bits.
- If this is a problem for you, please let us know how to fix it for
- your host. */
-# define TYPE_MINIMUM(t) \
- ((t) (! TYPE_SIGNED (t) \
- ? (t) 0 \
- : TYPE_SIGNED_MAGNITUDE (t) \
- ? ~ (t) 0 \
- : ~ TYPE_MAXIMUM (t)))
-# define TYPE_MAXIMUM(t) \
- ((t) (! TYPE_SIGNED (t) \
- ? (t) -1 \
+/* Minimum and maximum values for integer types.
+ These macros have undefined behavior for signed types that either
+ have padding bits or do not use two's complement. If this is a
+ problem for you, please let us know how to fix it for your host. */
+
+/* The maximum and minimum values for the integer type T. */
+# define TYPE_MINIMUM(t) ((t) ~ TYPE_MAXIMUM (t))
+# define TYPE_MAXIMUM(t) \
+ ((t) (! TYPE_SIGNED (t) \
+ ? (t) -1 \
: ((((t) 1 << (sizeof (t) * CHAR_BIT - 2)) - 1) * 2 + 1)))
# ifndef ULLONG_MAX
diff --git a/lib/timegm.c b/lib/timegm.c
index 86bdac3..bf61244 100644
--- a/lib/timegm.c
+++ b/lib/timegm.c
@@ -22,7 +22,9 @@
#include <time.h>
-#ifndef _LIBC
+#ifdef _LIBC
+typedef time_t mktime_offset_t;
+#else
# undef __gmtime_r
# define __gmtime_r gmtime_r
# define __mktime_internal mktime_internal
@@ -32,7 +34,7 @@
time_t
timegm (struct tm *tmp)
{
- static time_t gmtime_offset;
+ static mktime_offset_t gmtime_offset;
tmp->tm_isdst = 0;
return __mktime_internal (tmp, __gmtime_r, &gmtime_offset);
}
diff --git a/m4/mktime.m4 b/m4/mktime.m4
index 78f16ba..5a0f2d8 100644
--- a/m4/mktime.m4
+++ b/m4/mktime.m4
@@ -1,4 +1,4 @@
-# serial 25
+# serial 26
dnl Copyright (C) 2002-2003, 2005-2007, 2009-2016 Free Software Foundation,
dnl Inc.
dnl This file is free software; the Free Software Foundation
@@ -7,9 +7,24 @@ 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
+])
+
AC_DEFUN([gl_FUNC_MKTIME],
[
AC_REQUIRE([gl_HEADER_TIME_H_DEFAULTS])
+ 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.
@@ -169,7 +184,6 @@ main ()
time_t t, delta;
int i, j;
int time_t_signed_magnitude = (time_t) ~ (time_t) 0 < (time_t) -1;
- int time_t_signed = ! ((time_t) 0 < (time_t) -1);
#if HAVE_DECL_ALARM
/* This test makes some buggy mktime implementations loop.
@@ -179,11 +193,11 @@ main ()
alarm (60);
#endif
- time_t_max = (! time_t_signed
+ 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_signed
+ time_t_min = (! TIME_T_IS_SIGNED
? (time_t) 0
: time_t_signed_magnitude
? ~ (time_t) 0
diff --git a/m4/std-gnu11.m4 b/m4/std-gnu11.m4
index e8d3ebc..10da26f 100644
--- a/m4/std-gnu11.m4
+++ b/m4/std-gnu11.m4
@@ -1,8 +1,8 @@
# Prefer GNU C11 and C++11 to earlier versions. -*- coding: utf-8 -*-
# This implementation is taken from GNU Autoconf lib/autoconf/c.m4
-# commit 739cdc82b5325402231f3f5e1a38f681fcbd1db2
-# dated Tue Mar 15 09:34:11 2016 -0700.
+# commit 017d5ddd82854911f0119691d91ea8a1438824d6
+# dated Sun Apr 3 13:57:17 2016 -0700
# This implementation will be obsolete once we can assume Autoconf 2.70
# or later is installed everywhere a Gnulib program might be developed.
@@ -707,7 +707,7 @@ AC_DEFUN([_AC_CXX_CXX11_TEST_BODY],
short sa[cxx11test::get_val()] = { 0 };
}
{
- // Test initialiser lists
+ // Test initializer lists
cxx11test::testinit il = { 4323, 435234.23544 };
}
{
@@ -801,7 +801,7 @@ dnl with extended modes being tried first.
# considers the compiler to be in ISO C++11 mode if it handles all the
# tests from the C++98 checks, plus the following: Language features
# (auto, constexpr, decltype, default/deleted constructors, delegate
-# constructors, final, initialiser lists, lambda functions, nullptr,
+# constructors, final, initializer lists, lambda functions, nullptr,
# override, range-based for loops, template brackets without spaces,
# unicode literals) and library features (array, memory (shared_ptr,
# weak_ptr), regex and tuple types).
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