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Sync from gnulib

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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.
This commit is contained in:
Paul Eggert 2016-05-01 18:36:38 -07:00
parent 13f4efb0fd
commit 3707f609cb
7 changed files with 263 additions and 339 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

45
lib/intprops.h
View file

@ -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__))

35
lib/mktime-internal.h
View file

@ -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 *);

455
lib/mktime.c
View file

@ -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. */
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));
}
/* True if the arithmetic type T is an integer type. bool counts as
an integer. */
#define TYPE_IS_INTEGER(t) ((t) 1.5 == 1)
/* Bounds for the intersection of time_t and long_int. */
/* 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)
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));
/* 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)));
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.
(ghazi@caip.rutgers.edu) */
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;

31
lib/strtol.c
View file

@ -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

6
lib/timegm.c
View file

@ -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);
}

22
m4/mktime.m4
View file

@ -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

8
m4/std-gnu11.m4
View file

@ -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).