X-Git-Url: http://erislabs.net/gitweb/?a=blobdiff_plain;f=lib%2Fmktime.c;h=ded3295c6f3ca1b7f3772c6735420d3c1b467aaa;hb=74fcb0575a5b053a1b1078a5595c1795790c63cb;hp=a928c8c34531c49a28d7a0051132a2435dfc3691;hpb=34d76dfed259882ddd510c8221c609756108d07a;p=gnulib.git diff --git a/lib/mktime.c b/lib/mktime.c index a928c8c34..ded3295c6 100644 --- a/lib/mktime.c +++ b/lib/mktime.c @@ -1,7 +1,7 @@ /* Convert a `struct tm' to a time_t value. - Copyright (C) 1993-1999, 2002-2004, 2005 Free Software Foundation, Inc. + Copyright (C) 1993-1999, 2002-2005, 2006 Free Software Foundation, Inc. This file is part of the GNU C Library. - Contributed by Paul Eggert (eggert@twinsun.com). + Contributed by Paul Eggert . 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 @@ -15,7 +15,7 @@ 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ + Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */ /* Define this to have a standalone program to test this implementation of mktime. */ @@ -37,10 +37,11 @@ #include +#include /* For the real memcpy prototype. */ + #if DEBUG # include # include -# include /* Make it work even if the system's libc has its own mktime routine. */ # define mktime my_mktime #endif /* DEBUG */ @@ -60,13 +61,38 @@ ? (a) >> (b) \ : (a) / (1 << (b)) - ((a) % (1 << (b)) < 0)) -/* The extra casts work around common compiler bugs. */ +/* 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, 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 outer cast is needed to work around a bug in Cray C 5.0.3.0. - It is necessary at least when t == time_t. */ -#define TYPE_MINIMUM(t) ((t) (TYPE_SIGNED (t) \ - ? ~ (t) 0 << (sizeof (t) * CHAR_BIT - 1) : (t) 0)) -#define TYPE_MAXIMUM(t) ((t) (~ (t) 0 - TYPE_MINIMUM (t))) + +/* 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 \ + : ~ (t) 0 << (sizeof (t) * CHAR_BIT - 1))) +#define TYPE_MAXIMUM(t) \ + ((t) (! TYPE_SIGNED (t) \ + ? (t) -1 \ + : ~ (~ (t) 0 << (sizeof (t) * CHAR_BIT - 1)))) #ifndef TIME_T_MIN # define TIME_T_MIN TYPE_MINIMUM (time_t) @@ -79,8 +105,8 @@ /* 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, (time_t) 0.5 == 0); -verify (twos_complement_arithmetic, -1 == ~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. */ @@ -189,10 +215,11 @@ guess_time_tm (long int year, long int yday, int hour, int min, int sec, /* Overflow occurred one way or another. Return the nearest result that is actually in range, except don't report a zero difference if the actual difference is nonzero, as that would cause a false - match. */ + match; and don't oscillate between two values, as that would + confuse the spring-forward gap detector. */ return (*t < TIME_T_MIDPOINT - ? TIME_T_MIN + (*t == TIME_T_MIN) - : TIME_T_MAX - (*t == 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. @@ -202,14 +229,12 @@ static struct tm * ranged_convert (struct tm *(*convert) (const time_t *, struct tm *), time_t *t, struct tm *tp) { - struct tm *r; + struct tm *r = convert (t, tp); - if (! (r = (*convert) (t, tp)) && *t) + if (!r && *t) { time_t bad = *t; time_t ok = 0; - /* Initialize to make the compiler happy. */ - struct tm tm = { 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 @@ -219,11 +244,9 @@ ranged_convert (struct tm *(*convert) (const time_t *, struct tm *), time_t mid = *t = (bad < 0 ? bad + ((ok - bad) >> 1) : ok + ((bad - ok) >> 1)); - if ((r = (*convert) (t, tp))) - { - tm = *r; - ok = mid; - } + r = convert (t, tp); + if (r) + ok = mid; else bad = mid; } @@ -233,8 +256,7 @@ ranged_convert (struct tm *(*convert) (const time_t *, struct tm *), /* The last conversion attempt failed; revert to the most recent successful attempt. */ *t = ok; - *tp = tm; - r = tp; + r = convert (t, tp); } } @@ -463,7 +485,7 @@ __mktime_internal (struct tm *tp, t2 = t1 + sec_adjustment; if (((t1 < t) != (sec_requested < 0)) | ((t2 < t1) != (sec_adjustment < 0)) - | ! (*convert) (&t2, &tm)) + | ! convert (&t2, &tm)) return -1; t = t2; }