From 48a6c46b0b7e993aecf5c09386afd554165506ff Mon Sep 17 00:00:00 2001 From: Paul Eggert Date: Fri, 16 Nov 2018 08:13:39 -0800 Subject: [PATCH] autoupdate --- lib/mktime.c | 391 +++++++++++++++++++---------------------------------------- 1 file changed, 125 insertions(+), 266 deletions(-) diff --git a/lib/mktime.c b/lib/mktime.c index 00f0dec6b4..8faa9bc93d 100644 --- a/lib/mktime.c +++ b/lib/mktime.c @@ -17,12 +17,6 @@ License along with the GNU C Library; if not, see . */ -/* Define this to 1 to have a standalone program to test this implementation of - mktime. */ -#ifndef DEBUG_MKTIME -# define DEBUG_MKTIME 0 -#endif - /* The following macros influence what gets defined when this file is compiled: Macro/expression Which gnulib module This compilation unit @@ -34,12 +28,10 @@ || NEED_MKTIME_WINDOWS NEED_MKTIME_INTERNAL mktime-internal mktime_internal - - DEBUG_MKTIME (defined manually) my_mktime, main */ -#if !defined _LIBC && !DEBUG_MKTIME -# include +#ifndef _LIBC +# include #endif /* Assume that leap seconds are possible, unless told otherwise. @@ -51,6 +43,7 @@ #include +#include #include #include #include @@ -59,13 +52,6 @@ #include #include -#if DEBUG_MKTIME -# include -/* Make it work even if the system's libc has its own mktime routine. */ -# undef mktime -# define mktime my_mktime -#endif /* DEBUG_MKTIME */ - #ifndef NEED_MKTIME_INTERNAL # define NEED_MKTIME_INTERNAL 0 #endif @@ -73,7 +59,7 @@ # define NEED_MKTIME_WINDOWS 0 #endif #ifndef NEED_MKTIME_WORKING -# define NEED_MKTIME_WORKING DEBUG_MKTIME +# define NEED_MKTIME_WORKING 0 #endif #include "mktime-internal.h" @@ -119,11 +105,12 @@ my_tzset (void) #if defined _LIBC || NEED_MKTIME_WORKING || NEED_MKTIME_INTERNAL /* A signed type that can represent an integer number of years - multiplied by three times the number of seconds in a year. It is + multiplied by four 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 + in a year. The factor of four comes because these products need to be subtracted from each other, and sometimes with an offset - added to them, without worrying about overflow. + added to them, and then with another timestamp added, without + worrying about overflow. Much of the code uses long_int to represent time_t values, to lessen the hassle of dealing with platforms where time_t is @@ -131,12 +118,12 @@ my_tzset (void) 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 +#if INT_MAX <= LONG_MAX / 4 / 366 / 24 / 60 / 60 typedef long int long_int; #else typedef long long int long_int; #endif -verify (INT_MAX <= TYPE_MAXIMUM (long_int) / 3 / 366 / 24 / 60 / 60); +verify (INT_MAX <= TYPE_MAXIMUM (long_int) / 4 / 366 / 24 / 60 / 60); /* Shift A right by B bits portably, by dividing A by 2**B and truncating towards minus infinity. B should be in the range 0 <= B @@ -210,9 +197,10 @@ isdst_differ (int a, int b) were not adjusted between the timestamps. The YEAR values uses the same numbering as TP->tm_year. Values - 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. */ + need not be in the usual range. However, YEAR1 - YEAR0 must not + overflow even when multiplied by three times the number of seconds + in a year, and likewise for YDAY1 - YDAY0 and three times the + number of seconds in a day. */ static long_int ydhms_diff (long_int year1, long_int yday1, int hour1, int min1, int sec1, @@ -247,43 +235,25 @@ long_int_avg (long_int a, long_int b) 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 - occurred between *TP and the desired time. - 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. +/* Return a long_int value corresponding to (YEAR-YDAY HOUR:MIN:SEC) + minus *TP seconds, assuming no clock adjustments occurred between + the two timestamps. + 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. */ + *TP should be in the usual range. */ static long_int -guess_time_tm (long_int year, long_int yday, int hour, int min, int sec, - long_int t, const struct tm *tp) +tm_diff (long_int year, long_int yday, int hour, int min, int sec, + struct tm const *tp) { - if (tp) - { - 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 - 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; and don't oscillate between two values, as that would - confuse the spring-forward gap detector. */ - 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)); + return ydhms_diff (year, yday, hour, min, sec, + tp->tm_year, tp->tm_yday, + tp->tm_hour, tp->tm_min, tp->tm_sec); } /* Use CONVERT to convert T to a struct tm value in *TM. T must be in - range for time_t. Return TM if successful, NULL if T is out of - range for CONVERT. */ + range for time_t. Return TM if successful, NULL (setting errno) on + failure. */ static struct tm * convert_time (struct tm *(*convert) (const time_t *, struct tm *), long_int t, struct tm *tm) @@ -295,47 +265,48 @@ convert_time (struct tm *(*convert) (const time_t *, struct 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. - A value is in range if it fits in both time_t and long_int. */ + A value is in range if it fits in both time_t and long_int. + Return TP on success, NULL (setting errno) on failure. */ static struct tm * ranged_convert (struct tm *(*convert) (const time_t *, struct tm *), long_int *t, struct tm *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) + long_int t1 = (*t < mktime_min ? mktime_min + : *t <= mktime_max ? *t : mktime_max); + struct tm *r = convert_time (convert, t1, tp); + if (r) { - long_int bad = *t; - long_int ok = 0; + *t = t1; + return r; + } + if (errno != EOVERFLOW) + return NULL; - /* 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 (true) - { - 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 - bad = mid; - } + long_int bad = t1; + long_int ok = 0; + struct tm oktm; oktm.tm_sec = -1; - if (!r && ok) - { - /* The last conversion attempt failed; - revert to the most recent successful attempt. */ - r = convert_time (convert, ok, tp); - } + /* BAD is a known out-of-range value, and OK is a known in-range one. + Use binary search to narrow the range between BAD and OK until + they differ by 1. */ + while (true) + { + long_int mid = long_int_avg (ok, bad); + if (mid == ok || mid == bad) + break; + if (convert_time (convert, mid, tp)) + ok = mid, oktm = *tp; + else if (errno != EOVERFLOW) + return NULL; + else + bad = mid; } - return r; + if (oktm.tm_sec < 0) + return NULL; + *t = ok; + *tp = oktm; + return tp; } @@ -344,13 +315,14 @@ ranged_convert (struct tm *(*convert) (const time_t *, struct tm *), Use *OFFSET to keep track of a guess at the offset of the result, compared to what the result would be for UTC without leap seconds. If *OFFSET's guess is correct, only one CONVERT call is needed. + If successful, set *TP to the canonicalized struct tm; + otherwise leave *TP alone, return ((time_t) -1) and set errno. 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 *), mktime_offset_t *offset) { - long_int t, gt, t0, t1, t2, dt; struct tm tm; /* The maximum number of probes (calls to CONVERT) should be enough @@ -370,7 +342,7 @@ __mktime_internal (struct tm *tp, int isdst = tp->tm_isdst; /* 1 if the previous probe was DST. */ - int dst2; + int dst2 = 0; /* Ensure that mon is in range, and set year accordingly. */ int mon_remainder = mon % 12; @@ -398,7 +370,7 @@ __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_diff assumes every minute has 60 seconds. */ if (sec < 0) sec = 0; if (59 < sec) @@ -409,33 +381,46 @@ __mktime_internal (struct tm *tp, time. */ INT_SUBTRACT_WRAPV (0, off, &negative_offset_guess); - t0 = ydhms_diff (year, yday, hour, min, sec, - EPOCH_YEAR - TM_YEAR_BASE, 0, 0, 0, negative_offset_guess); + long_int t0 = ydhms_diff (year, yday, hour, min, sec, + EPOCH_YEAR - TM_YEAR_BASE, 0, 0, 0, + negative_offset_guess); + long_int t = t0, t1 = t0, t2 = 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); - 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)))) - /* 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. */ - goto offset_found; - else if (--remaining_probes == 0) - return -1; + while (true) + { + if (! ranged_convert (convert, &t, &tm)) + return -1; + long_int dt = tm_diff (year, yday, hour, min, sec, &tm); + if (dt == 0) + break; + + if (t == t1 && t != t2 + && (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 DT. Follow the common + practice in this case, which is to return a time that is DT + 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; + + remaining_probes--; + if (remaining_probes == 0) + { + __set_errno (EOVERFLOW); + return -1; + } + + t1 = t2, t2 = t, t += dt, dst2 = tm.tm_isdst != 0; + } /* We have a match. Check whether tm.tm_isdst has the requested value, if any. */ @@ -477,25 +462,38 @@ __mktime_internal (struct tm *tp, if (! INT_ADD_WRAPV (t, delta * direction, &ot)) { struct tm otm; - ranged_convert (convert, &ot, &otm); + if (! ranged_convert (convert, &ot, &otm)) + return -1; 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 gt = ot + tm_diff (year, yday, hour, min, sec, + &otm); + if (mktime_min <= gt && gt <= mktime_max) + { + if (convert_time (convert, gt, &tm)) + { + t = gt; + goto offset_found; + } + if (errno != EOVERFLOW) + return -1; + } } } } + + __set_errno (EOVERFLOW); + return -1; } offset_found: /* 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); + INT_SUBTRACT_WRAPV (t, t0, offset); + INT_SUBTRACT_WRAPV (*offset, negative_offset_guess, offset); if (LEAP_SECONDS_POSSIBLE && sec_requested != tm.tm_sec) { @@ -505,8 +503,12 @@ __mktime_internal (struct tm *tp, 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)) + || ! (mktime_min <= t && t <= mktime_max)) + { + __set_errno (EOVERFLOW); + return -1; + } + if (! convert_time (convert, t, &tm)) return -1; } @@ -545,146 +547,3 @@ weak_alias (mktime, timelocal) libc_hidden_def (mktime) libc_hidden_weak (timelocal) #endif - -#if DEBUG_MKTIME - -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) - | isdst_differ (a->tm_isdst, b->tm_isdst)); -} - -static void -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); - else - printf ("0"); -} - -static int -check_result (time_t tk, struct tm tmk, time_t tl, const struct tm *lt) -{ - if (tk != tl || !lt || not_equal_tm (&tmk, lt)) - { - printf ("mktime ("); - print_tm (lt); - printf (")\nyields ("); - print_tm (&tmk); - printf (") == %ld, should be %ld\n", (long int) tk, (long int) tl); - return 1; - } - - return 0; -} - -int -main (int argc, char **argv) -{ - int status = 0; - struct tm tm, tmk, tml; - struct tm *lt; - 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) - == 3) - && (sscanf (argv[2], "%d:%d:%d%c", - &tm.tm_hour, &tm.tm_min, &tm.tm_sec, &trailer) - == 3)) - { - tm.tm_year -= TM_YEAR_BASE; - tm.tm_mon--; - tm.tm_isdst = argc == 3 ? -1 : atoi (argv[3]); - tmk = tm; - tl = mktime (&tmk); - lt = localtime_r (&tl, &tml); - printf ("mktime returns %ld == ", (long int) tl); - print_tm (&tmk); - printf ("\n"); - status = check_result (tl, tmk, tl, lt); - } - else if (argc == 4 || (argc == 5 && strcmp (argv[4], "-") == 0)) - { - time_t from = atol (argv[1]); - time_t by = atol (argv[2]); - time_t to = atol (argv[3]); - - if (argc == 4) - for (tl = from; by < 0 ? to <= tl : tl <= to; tl = tl1) - { - lt = localtime_r (&tl, &tml); - if (lt) - { - tmk = tml; - tk = mktime (&tmk); - status |= check_result (tk, tmk, tl, &tml); - } - else - { - printf ("localtime_r (%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_r (&tl, &tml); - if (lt) - { - tmk = tml; - tk = tl; - status |= check_result (tk, tmk, tl, &tml); - } - else - { - printf ("localtime_r (%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]); - - return status; -} - -#endif /* DEBUG_MKTIME */ - -/* -Local Variables: -compile-command: "gcc -DDEBUG_MKTIME -I. -Wall -W -O2 -g mktime.c -o mktime" -End: -*/ -- 2.11.4.GIT