diff options
Diffstat (limited to 'gl/mktime.c')
| -rw-r--r-- | gl/mktime.c | 544 |
1 files changed, 308 insertions, 236 deletions
diff --git a/gl/mktime.c b/gl/mktime.c index b0324b82..e660a23c 100644 --- a/gl/mktime.c +++ b/gl/mktime.c @@ -1,21 +1,21 @@ -/* Convert a `struct tm' to a time_t value. - Copyright (C) 1993-1999, 2002-2007, 2009-2010 Free Software Foundation, Inc. +/* Convert a 'struct tm' to a time_t value. + Copyright (C) 1993-2013 Free Software Foundation, Inc. This file is part of the GNU C Library. Contributed by Paul Eggert <eggert@twinsun.com>. - 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, or (at your option) - any later version. + The GNU C Library 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, + The GNU C Library 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. + 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, write to the Free Software Foundation, - Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */ + You should have received a copy of the GNU General Public + 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 mktime. */ @@ -26,7 +26,7 @@ #endif /* Assume that leap seconds are possible, unless told otherwise. - If the host has a `zic' command with a `-L leapsecondfilename' option, + If the host has a 'zic' command with a '-L leapsecondfilename' option, then it supports leap seconds; otherwise it probably doesn't. */ #ifndef LEAP_SECONDS_POSSIBLE # define LEAP_SECONDS_POSSIBLE 1 @@ -36,15 +36,49 @@ #include <limits.h> -#include <string.h> /* For the real memcpy prototype. */ +#include <string.h> /* For the real memcpy prototype. */ #if DEBUG # include <stdio.h> # include <stdlib.h> /* Make it work even if the system's libc has its own mktime routine. */ +# undef mktime # define mktime my_mktime #endif /* DEBUG */ +/* 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 is at least one bit wider than int. */ +#if INT_MAX <= LONG_MAX / 2 +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); + /* 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 @@ -55,9 +89,11 @@ 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 \ - ? (a) >> (b) \ +#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, @@ -68,12 +104,8 @@ #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. */ + complement, or if T is an unsigned integer type. */ #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)) @@ -84,14 +116,12 @@ your host. */ #define TYPE_MINIMUM(t) \ ((t) (! TYPE_SIGNED (t) \ - ? (t) 0 \ - : TYPE_SIGNED_MAGNITUDE (t) \ - ? ~ (t) 0 \ - : ~ (t) 0 << (sizeof (t) * CHAR_BIT - 1))) + ? (t) 0 \ + : ~ TYPE_MAXIMUM (t))) #define TYPE_MAXIMUM(t) \ ((t) (! TYPE_SIGNED (t) \ - ? (t) -1 \ - : ~ (~ (t) 0 << (sizeof (t) * CHAR_BIT - 1)))) + ? (t) -1 \ + : ((((t) 1 << (sizeof (t) * CHAR_BIT - 2)) - 1) * 2 + 1))) #ifndef TIME_T_MIN # define TIME_T_MIN TYPE_MINIMUM (time_t) @@ -101,29 +131,26 @@ #endif #define TIME_T_MIDPOINT (SHR (TIME_T_MIN + TIME_T_MAX, 1) + 1) -/* Verify a requirement at compile-time (unlike assert, which is runtime). */ -#define verify(name, assertion) struct name { char a[(assertion) ? 1 : -1]; } - verify (time_t_is_integer, TYPE_IS_INTEGER (time_t)); -verify (twos_complement_arithmetic, TYPE_TWOS_COMPLEMENT (int)); -/* The code also assumes that signed integer overflow silently wraps - around, but this assumption can't be stated without causing a - diagnostic on some hosts. */ +verify (twos_complement_arithmetic, + (TYPE_TWOS_COMPLEMENT (int) + && TYPE_TWOS_COMPLEMENT (long_int) + && TYPE_TWOS_COMPLEMENT (time_t))); #define EPOCH_YEAR 1970 #define TM_YEAR_BASE 1900 verify (base_year_is_a_multiple_of_100, TM_YEAR_BASE % 100 == 0); /* Return 1 if YEAR + TM_YEAR_BASE is a leap year. */ -static inline int -leapyear (long int year) +static int +leapyear (long_int year) { /* Don't add YEAR to TM_YEAR_BASE, as that might overflow. Also, work even if YEAR is negative. */ return ((year & 3) == 0 && (year % 100 != 0 - || ((year / 100) & 3) == (- (TM_YEAR_BASE / 100) & 3))); + || ((year / 100) & 3) == (- (TM_YEAR_BASE / 100) & 3))); } /* How many days come before each month (0-12). */ @@ -150,6 +177,14 @@ 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 +isdst_differ (int a, int b) +{ + return (!a != !b) && (0 <= a) && (0 <= b); +} + /* Return an integer value measuring (YEAR1-YDAY1 HOUR1:MIN1:SEC1) - (YEAR0-YDAY0 HOUR0:MIN0:SEC0) in seconds, assuming that the clocks were not adjusted between the time stamps. @@ -161,16 +196,11 @@ const unsigned short int __mon_yday[2][13] = The result may overflow. It is the caller's responsibility to detect overflow. */ -static inline time_t -ydhms_diff (long int year1, long int yday1, int hour1, int min1, int sec1, - int year0, int yday0, int hour0, int min0, int sec0) +static time_t +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); -#if 0 /* This assertion fails on 32-bit systems with 64-bit time_t, such as - NetBSD 5 on i386. */ - verify (long_int_year_and_yday_are_wide_enough, - INT_MAX <= LONG_MAX / 2 || TIME_T_MAX <= UINT_MAX); -#endif /* Compute intervening leap days correctly even if year is negative. Take care to avoid integer overflow here. */ @@ -193,6 +223,53 @@ ydhms_diff (long int year1, long int yday1, int hour1, int min1, int sec1, 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 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 a time_t value corresponding to (YEAR-YDAY HOUR:MIN:SEC), assuming that *T corresponds to *TP and that no clock adjustments @@ -201,17 +278,16 @@ ydhms_diff (long int year1, long int yday1, int hour1, int min1, int sec1, If overflow occurs, yield the minimal or maximal value, except do not yield a value equal to *T. */ static time_t -guess_time_tm (long int year, long int yday, int hour, int min, int sec, - const time_t *t, const struct tm *tp) +guess_time_tm (long_int year, long_int yday, int hour, int min, int sec, + const time_t *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); - time_t t1 = *t + d; - if ((t1 < *t) == (TYPE_SIGNED (time_t) ? d < 0 : TIME_T_MAX / 2 < d)) - return t1; + 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; } /* Overflow occurred one way or another. Return the nearest result @@ -220,8 +296,8 @@ guess_time_tm (long int year, long int yday, int hour, int min, int sec, 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)); + ? (*t <= TIME_T_MIN + 1 ? *t + 1 : TIME_T_MIN) + : (TIME_T_MAX - 1 <= *t ? *t - 1 : TIME_T_MAX)); } /* Use CONVERT to convert *T to a broken down time in *TP. @@ -229,7 +305,7 @@ guess_time_tm (long int year, long int yday, int hour, int min, int sec, it is the nearest in-range value and then convert that. */ static struct tm * ranged_convert (struct tm *(*convert) (const time_t *, struct tm *), - time_t *t, struct tm *tp) + time_t *t, struct tm *tp) { struct tm *r = convert (t, tp); @@ -239,27 +315,25 @@ ranged_convert (struct tm *(*convert) (const time_t *, struct tm *), time_t ok = 0; /* BAD is a known unconvertible time_t, and OK is a known good one. - Use binary search to narrow the range between BAD and OK until - they differ by 1. */ + Use binary search to narrow the range between BAD and OK until + they differ by 1. */ while (bad != ok + (bad < 0 ? -1 : 1)) - { - time_t mid = *t = (bad < 0 - ? bad + ((ok - bad) >> 1) - : ok + ((bad - ok) >> 1)); - r = convert (t, tp); - if (r) - ok = mid; - else - bad = mid; - } + { + time_t mid = *t = time_t_avg (ok, bad); + r = convert (t, tp); + if (r) + ok = mid; + else + bad = mid; + } if (!r && ok) - { - /* The last conversion attempt failed; - revert to the most recent successful attempt. */ - *t = ok; - r = convert (t, tp); - } + { + /* The last conversion attempt failed; + revert to the most recent successful attempt. */ + *t = ok; + r = convert (t, tp); + } } return r; @@ -274,8 +348,8 @@ ranged_convert (struct tm *(*convert) (const time_t *, struct tm *), This function is external because it is used also by timegm.c. */ time_t __mktime_internal (struct tm *tp, - struct tm *(*convert) (const time_t *, struct tm *), - time_t *offset) + struct tm *(*convert) (const time_t *, struct tm *), + time_t *offset) { time_t t, gt, t0, t1, t2; struct tm tm; @@ -294,9 +368,7 @@ __mktime_internal (struct tm *tp, int mday = tp->tm_mday; int mon = tp->tm_mon; int year_requested = tp->tm_year; - /* Normalize the value. */ - int isdst = ((tp->tm_isdst >> (8 * sizeof (tp->tm_isdst) - 1)) - | (tp->tm_isdst != 0)); + int isdst = tp->tm_isdst; /* 1 if the previous probe was DST. */ int dst2; @@ -305,8 +377,8 @@ __mktime_internal (struct tm *tp, int mon_remainder = mon % 12; int negative_mon_remainder = mon_remainder < 0; int mon_years = mon / 12 - negative_mon_remainder; - long int lyear_requested = year_requested; - long int year = lyear_requested + mon_years; + long_int lyear_requested = year_requested; + long_int year = lyear_requested + mon_years; /* The other values need not be in range: the remaining code handles minor overflows correctly, @@ -316,10 +388,10 @@ __mktime_internal (struct tm *tp, /* Calculate day of year from year, month, and day of month. The result need not be in range. */ int mon_yday = ((__mon_yday[leapyear (year)] - [mon_remainder + 12 * negative_mon_remainder]) - - 1); - long int lmday = mday; - long int yday = mon_yday + lmday; + [mon_remainder + 12 * negative_mon_remainder]) + - 1); + long_int lmday = mday; + long_int yday = mon_yday + lmday; time_t guessed_offset = *offset; @@ -328,33 +400,33 @@ __mktime_internal (struct tm *tp, if (LEAP_SECONDS_POSSIBLE) { /* Handle out-of-range seconds specially, - since ydhms_tm_diff assumes every minute has 60 seconds. */ + since ydhms_tm_diff assumes every minute has 60 seconds. */ if (sec < 0) - sec = 0; + sec = 0; if (59 < sec) - sec = 59; + sec = 59; } /* Invert CONVERT by probing. First assume the same offset as last time. */ t0 = ydhms_diff (year, yday, hour, min, sec, - EPOCH_YEAR - TM_YEAR_BASE, 0, 0, 0, - guessed_offset); + 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. */ + 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. */ + 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; @@ -362,119 +434,117 @@ __mktime_internal (struct tm *tp, 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))); + (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 abs_diff = diff < 0 ? - diff : diff; + int approx_abs_diff = diff < 0 ? -1 - diff : diff; - /* IRIX 4.0.5 cc miscaculates 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) */ + /* 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 < 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; - abs_diff = diff < 0 ? - diff : diff; - if (overflow_threshold < abs_diff) - return -1; - guessed_offset += repaired_t0 - t0; - t0 = repaired_t0; - } + (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; + } } /* 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, - ranged_convert (convert, &t, &tm)), - t != gt); + ranged_convert (convert, &t, &tm)), + t != gt); t1 = t2, t2 = t, t = gt, dst2 = tm.tm_isdst != 0) if (t == t1 && t != t2 - && (tm.tm_isdst < 0 - || (isdst < 0 - ? dst2 <= (tm.tm_isdst != 0) - : (isdst != 0) != (tm.tm_isdst != 0)))) + && (tm.tm_isdst < 0 + || (isdst < 0 + ? dst2 <= (tm.tm_isdst != 0) + : (isdst != 0) != (tm.tm_isdst != 0)))) /* We can't possibly find a match, as we are oscillating - between two values. The requested time probably falls - within a spring-forward gap of size GT - T. Follow the common - practice in this case, which is to return a time that is GT - T - away from the requested time, preferring a time whose - tm_isdst differs from the requested value. (If no tm_isdst - was requested and only one of the two values has a nonzero - tm_isdst, prefer that value.) In practice, this is more - useful than returning -1. */ + between two values. The requested time probably falls + within a spring-forward gap of size GT - T. Follow the common + practice in this case, which is to return a time that is GT - T + away from the requested time, preferring a time whose + tm_isdst differs from the requested value. (If no tm_isdst + was requested and only one of the two values has a nonzero + tm_isdst, prefer that value.) In practice, this is more + useful than returning -1. */ goto offset_found; else if (--remaining_probes == 0) return -1; /* We have a match. Check whether tm.tm_isdst has the requested value, if any. */ - if (isdst != tm.tm_isdst && 0 <= isdst && 0 <= tm.tm_isdst) + if (isdst_differ (isdst, tm.tm_isdst)) { /* tm.tm_isdst has the wrong value. Look for a neighboring - time with the right value, and use its UTC offset. + time with the right value, and use its UTC offset. - Heuristic: probe the adjacent timestamps in both directions, - looking for the desired isdst. This should work for all real - time zone histories in the tz database. */ + Heuristic: probe the adjacent timestamps in both directions, + looking for the desired isdst. This should work for all real + time zone histories in the tz database. */ /* Distance between probes when looking for a DST boundary. In - tzdata2003a, the shortest period of DST is 601200 seconds - (e.g., America/Recife starting 2000-10-08 01:00), and the - shortest period of non-DST surrounded by DST is 694800 - seconds (Africa/Tunis starting 1943-04-17 01:00). Use the - minimum of these two values, so we don't miss these short - periods when probing. */ + tzdata2003a, the shortest period of DST is 601200 seconds + (e.g., America/Recife starting 2000-10-08 01:00), and the + shortest period of non-DST surrounded by DST is 694800 + seconds (Africa/Tunis starting 1943-04-17 01:00). Use the + minimum of these two values, so we don't miss these short + periods when probing. */ int stride = 601200; /* The longest period of DST in tzdata2003a is 536454000 seconds - (e.g., America/Jujuy starting 1946-10-01 01:00). The longest - period of non-DST is much longer, but it makes no real sense - to search for more than a year of non-DST, so use the DST - max. */ + (e.g., America/Jujuy starting 1946-10-01 01:00). The longest + period of non-DST is much longer, but it makes no real sense + to search for more than a year of non-DST, so use the DST + max. */ int duration_max = 536454000; /* Search in both directions, so the maximum distance is half - the duration; add the stride to avoid off-by-1 problems. */ + the duration; add the stride to avoid off-by-1 problems. */ int delta_bound = duration_max / 2 + stride; int delta, direction; for (delta = stride; delta < delta_bound; delta += stride) - for (direction = -1; direction <= 1; direction += 2) - { - time_t ot = t + delta * direction; - if ((ot < t) == (direction < 0)) - { - struct tm otm; - ranged_convert (convert, &ot, &otm); - if (otm.tm_isdst == 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; - } - } - } + 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; + } + } } offset_found: @@ -483,14 +553,16 @@ __mktime_internal (struct tm *tp, 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. */ + 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)) + return -1; t1 = t + sec_requested; + if (! time_t_int_add_ok (t1, sec_adjustment)) + return -1; t2 = t1 + sec_adjustment; - if (((t1 < t) != (sec_requested < 0)) - | ((t2 < t1) != (sec_adjustment < 0)) - | ! convert (&t2, &tm)) - return -1; + if (! convert (&t2, &tm)) + return -1; t = t2; } @@ -511,7 +583,7 @@ mktime (struct tm *tp) { #ifdef _LIBC /* POSIX.1 8.1.1 requires that whenever mktime() is called, the - time zone names contained in the external variable `tzname' shall + time zone names contained in the external variable 'tzname' shall be set as if the tzset() function had been called. */ __tzset (); #endif @@ -534,13 +606,13 @@ static int not_equal_tm (const struct tm *a, const struct tm *b) { return ((a->tm_sec ^ b->tm_sec) - | (a->tm_min ^ b->tm_min) - | (a->tm_hour ^ b->tm_hour) - | (a->tm_mday ^ b->tm_mday) - | (a->tm_mon ^ b->tm_mon) - | (a->tm_year ^ b->tm_year) - | (a->tm_yday ^ b->tm_yday) - | (a->tm_isdst ^ b->tm_isdst)); + | (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_yday ^ b->tm_yday) + | isdst_differ (a->tm_isdst, b->tm_isdst)); } static void @@ -548,9 +620,9 @@ print_tm (const struct tm *tp) { if (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); + 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); else printf ("0"); } @@ -582,11 +654,11 @@ main (int argc, char **argv) if ((argc == 3 || argc == 4) && (sscanf (argv[1], "%d-%d-%d%c", - &tm.tm_year, &tm.tm_mon, &tm.tm_mday, &trailer) - == 3) + &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)) + &tm.tm_hour, &tm.tm_min, &tm.tm_sec, &trailer) + == 3)) { tm.tm_year -= TM_YEAR_BASE; tm.tm_mon--; @@ -595,10 +667,10 @@ main (int argc, char **argv) tl = mktime (&tmk); lt = localtime (&tl); if (lt) - { - tml = *lt; - lt = &tml; - } + { + tml = *lt; + lt = &tml; + } printf ("mktime returns %ld == ", (long int) tl); print_tm (&tmk); printf ("\n"); @@ -611,51 +683,51 @@ main (int argc, char **argv) time_t to = atol (argv[3]); if (argc == 4) - for (tl = from; by < 0 ? to <= tl : tl <= to; tl = tl1) - { - lt = localtime (&tl); - if (lt) - { - tmk = tml = *lt; - tk = mktime (&tmk); - status |= check_result (tk, tmk, tl, &tml); - } - else - { - printf ("localtime (%ld) yields 0\n", (long int) tl); - status = 1; - } - tl1 = tl + by; - if ((tl1 < tl) != (by < 0)) - break; - } + for (tl = from; by < 0 ? to <= tl : tl <= to; tl = tl1) + { + lt = localtime (&tl); + if (lt) + { + tmk = tml = *lt; + tk = mktime (&tmk); + status |= check_result (tk, tmk, tl, &tml); + } + else + { + printf ("localtime (%ld) yields 0\n", (long int) tl); + status = 1; + } + tl1 = tl + by; + if ((tl1 < tl) != (by < 0)) + break; + } else - for (tl = from; by < 0 ? to <= tl : tl <= to; tl = tl1) - { - /* Null benchmark. */ - lt = localtime (&tl); - if (lt) - { - tmk = tml = *lt; - tk = tl; - status |= check_result (tk, tmk, tl, &tml); - } - else - { - printf ("localtime (%ld) yields 0\n", (long int) tl); - status = 1; - } - tl1 = tl + by; - if ((tl1 < tl) != (by < 0)) - break; - } + for (tl = from; by < 0 ? to <= tl : tl <= to; tl = tl1) + { + /* Null benchmark. */ + lt = localtime (&tl); + if (lt) + { + tmk = tml = *lt; + tk = tl; + status |= check_result (tk, tmk, tl, &tml); + } + else + { + printf ("localtime (%ld) yields 0\n", (long int) tl); + status = 1; + } + tl1 = tl + by; + if ((tl1 < tl) != (by < 0)) + break; + } } 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[0], argv[0], argv[0]); return status; } @@ -664,6 +736,6 @@ main (int argc, char **argv) /* Local Variables: -compile-command: "gcc -DDEBUG -Wall -W -O -g mktime.c -o mktime" +compile-command: "gcc -DDEBUG -I. -Wall -W -O2 -g mktime.c -o mktime" End: */ |