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https://frontier.innolan.net/rainlance/amiga-tz.git
synced 2026-09-24 04:31:39 +00:00
Paul Eggert
f0133dd86a
I audited the code and fixed as many width-asssumptions as I could find, including several places where the code assumed that 'time_t' was no wider than 'long'; this assumption is not true on 32-bit NetBSD platforms. This caught every problem that is already fixed in the NetBSD zic.c, and caught quite a few more. * Makefile: Add comments re HAVE_DOS_FILE_NAMES and HAVE_INTTYPES_H. * date.c (checkfinal, netsettime): Don't use 'long' where 'int' will do. * difftime.c (difftime): Mark with ATTRIBUTE_CONST. Use uintmax_t, not unsigned long, for the widest unsigned integer type. Use long double, not double, if time_t is wider than uintmax_t; this can in theory help on nonstandard platforms, such as GCC with 64-bit uintmax_t and 128-bit __int128_t. * localtime.c (struct ttinfo.tt_gmtoff, struct rule.r_time) (detzcode, getsecs, getoffset, gmtsub, localsub, increment_overflow32) (normalize_overflow32, time1, time2, timesub, transtime, tzparse) (time2sub, timeoff, gtime): * tzfile.h (SECSPERDAY): * zdump.c (SECSPERDAY): * zic.c (convert, puttzcode): Use int_fast32_t, not long, when all we care is that values up to 2**31 can be stored. This doesn't fix any bugs, but it allows more opportunity for compiler optimization. (struct lsinfo.ls_corr, timesub, leapcorr): Use int_fast64_t, not long, when values up to 2**63 can be stored. (timesub): Make it clearer when we are truncating 0.5 to 0. (increment_overflow32): Rename from long_increment_overflow. All uses changed. (normalize_overflow32): Rename from long_normalize_overflow. All uses changed. * private.h (HAVE_INTTYPES_H, ATTRIBUTE_CONST): New macros. Include <inttypes.h> if HAVE_INTTYPES_H. (INT_FAST64_MIN, INT_FAST64_MAX, SCNdFAST64, int_fast32_t, PRIdMAX) (uintmax_t, PRIuMAX, _Noreturn): Define to reasonable values if it's an older compiler. * scheck.c (scheck): Add support for arbitrary formats, such as those that SCNdFAST64 can expand to, at the price of no longer supporting weird conversion specs like "%[%]". * strftime.c (_fmt): Use intmax_t and uintmax_t to format time_t, not long and unsigned long. * zdump.c (int_fast32_t, intmax_t, PRIdMAX, SCNdMAX): Define for pre-C99 compilers, like private.h does. (delta, yeartot, main): Use intmax_t, not long. (hunt): Use time_t, not long, since the diff must be nonnegative. (tformat): Allow for time_t wider than long. * zic.c (ZIC_MIN, ZIC_MAX, SCNdZIC): New macros. (OFFSET_STRLEN_MAXIMUM, RULE_STRLEN_MAXIMUM): Remove. (struct rule): Make r_loyear, r_hiyear, r_tod, r_stdoff, z_gmtoff, z_stdoff zic_t, not long. (addtype, gethms, oadd, rpytime, tadd, gmtoffs, corr, inleap) (stringoffset, stringrule, outzone, addtype, adjleap, rpytime) (LDAYSPERWEEK): Use zic_t, not long. (leapminyear, leapmaxyear, min_year, max_year, rulesub, updateminmax) (outzone, rpytime): Use zic_t, not int. (usage): Now _Noreturn. (main): Use S_IWGRP, not 'unix', to determine whether to call umask. (writezone): Omit unnecessary cast. (mkdirs): Use HAVE_DOS_FILE_NAMES, not 'unix', to determine whether to parse DOS file anmes. (eitol): Remove; no longer needed.
57 lines
1.6 KiB
C
57 lines
1.6 KiB
C
/*
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** This file is in the public domain, so clarified as of
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** 1996-06-05 by Arthur David Olson.
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*/
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/*LINTLIBRARY*/
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#include "private.h" /* for time_t, TYPE_INTEGRAL, and TYPE_SIGNED */
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double ATTRIBUTE_CONST
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difftime(const time_t time1, const time_t time0)
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{
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/*
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** If (sizeof (double) > sizeof (time_t)) simply convert and subtract
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** (assuming that the larger type has more precision).
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*/
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if (sizeof (double) > sizeof (time_t))
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return (double) time1 - (double) time0;
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if (!TYPE_INTEGRAL(time_t)) {
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/*
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** time_t is floating.
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*/
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return time1 - time0;
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}
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if (!TYPE_SIGNED(time_t)) {
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/*
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** time_t is integral and unsigned.
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** The difference of two unsigned values can't overflow
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** if the minuend is greater than or equal to the subtrahend.
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*/
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if (time1 >= time0)
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return time1 - time0;
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else return -(double) (time0 - time1);
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}
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/*
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** time_t is integral and signed.
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** Handle cases where both time1 and time0 have the same sign
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** (meaning that their difference cannot overflow).
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*/
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if ((time1 < 0) == (time0 < 0))
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return time1 - time0;
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/*
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** time1 and time0 have opposite signs.
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** Punt if uintmax_t is too narrow.
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** This suffers from double rounding; attempt to lessen that
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** by using long double temporaries.
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*/
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if (sizeof (uintmax_t) < sizeof (time_t))
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return (long double) time1 - (long double) time0;
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/*
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** Stay calm...decent optimizers will eliminate the complexity below.
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*/
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if (time1 >= 0 /* && time0 < 0 */)
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return (uintmax_t) time1 + (uintmax_t) (-1 - time0) + 1;
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return -(double) ((uintmax_t) time0 + (uintmax_t) (-1 - time1) + 1);
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}
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