From c00160817df41d1581b2e91620c4adb5cba19a74 Mon Sep 17 00:00:00 2001 From: Ulrich Drepper Date: Thu, 5 Nov 1998 12:26:43 +0000 Subject: Update. 1998-11-05 Ulrich Drepper * sysdeps/i386/fpu/bits/mathinline.h (__pow2): Fix fldl -> fld. * sysdeps/libm-i387/s_fma.S: Optimize a bit. * sysdeps/libm-i387/s_fmaf.S: Likewise. 1998-11-04 19:47 -0500 Zack Weinberg * configure.in: Search for install-info and substitute it. Determine whether install-info is the buggy Debian version that doesn't understand INFO-DIR-SECTION. * config.make.in: Add INSTALL_INFO and OLD_DEBIAN_INSTALL_INFO to be substituted. * manual/Makefile: If OLD_DEBIAN_INSTALL_INFO, give install-info the --section argument it needs to work properly. (dir-add.texinfo): Delete target. (dir-add.info): Generate this directly. Sort entries. Put a colon at the end of the INFO-DIR-SECTION line. * manual/libc.texinfo: Put a colon at the end of the @dircategory line. 1998-11-05 Paul Eggert * time/mktime.c (__mktime_internal): Adopt the traditional (and problematic) notion of what to do when tm_isdst doesn't match. 1998-11-04 Andreas Schwab * posix/PTESTS: Fix spelling. 1998-11-04 Andreas Jaeger * elf/dlopenold.c: Compile only if DO_VERSIONING is also defined. 1998-11-03 H.J. Lu * libio/fileops.c (new_do_write): New function. (_IO_new_do_write): Call new_do_write. (_IO_new_file_xsputn): Likewise. * libio/oldfileops.c (old_do_write): New function. (_IO_old_do_write): Call old_do_write. (_IO_old_file_xsputn): Likewise. --- time/mktime.c | 45 +++++++++++++++++++++++---------------------- 1 file changed, 23 insertions(+), 22 deletions(-) (limited to 'time/mktime.c') diff --git a/time/mktime.c b/time/mktime.c index 2908db0784..673bb48266 100644 --- a/time/mktime.c +++ b/time/mktime.c @@ -350,31 +350,32 @@ __mktime_internal (tp, convert, offset) /* If we have a match, check whether tm.tm_isdst has the requested value, if any. */ - if (dt == 0 && 0 <= isdst && 0 <= tm.tm_isdst) + if (dt == 0 && isdst != tm.tm_isdst && 0 <= isdst && 0 <= tm.tm_isdst) { - int dst_diff = (isdst != 0) - (tm.tm_isdst != 0); - if (dst_diff) + /* tm.tm_isdst has the wrong value. Look for a neighboring + time with the right value, and use its UTC offset. + Heuristic: probe the previous three calendar quarters (approximately), + looking for the desired isdst. This isn't perfect, + but it's good enough in practice. */ + int quarter = 7889238; /* seconds per average 1/4 Gregorian year */ + int i; + + /* If we're too close to the time_t limit, look in future quarters. */ + if (t < TIME_T_MIN + 3 * quarter) + quarter = -quarter; + + for (i = 1; i <= 3; i++) { - /* Move two hours in the direction indicated by the disagreement, - probe some more, and switch to a new time if found. - The largest known fallback due to daylight savings is two hours: - once, in Newfoundland, 1988-10-30 02:00 -> 00:00. */ - time_t ot = t - 2 * 60 * 60 * dst_diff; - while (--remaining_probes != 0) + time_t ot = t - i * quarter; + struct tm otm; + ranged_convert (convert, &ot, &otm); + if (otm.tm_isdst == isdst) { - struct tm otm; - dt = ydhms_tm_diff (year, yday, hour, min, sec, - ranged_convert (convert, &ot, &otm)); - if (dt == 0 - || (ot + dt == t - && dst_diff == (isdst != 0) - (tm.tm_isdst != 0))) - { - t = ot; - tm = otm; - break; - } - if ((ot += dt) == t) - break; /* Avoid a redundant probe. */ + /* We found the desired tm_isdst. + Extrapolate back to the desired time. */ + t = ot + ydhms_tm_diff (year, yday, hour, min, sec, &otm); + ranged_convert (convert, &t, &tm); + break; } } } -- cgit v1.2.3