diff mbox series

[49/59] Remove leap-second goto from __tzfile_compute

Message ID	20250105055750.1668721-50-eggert@cs.ucla.edu (mailing list archive)
State	New
Headers	DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org 9FBE53858430 From: Paul Eggert <eggert@cs.ucla.edu> To: libc-alpha@sourceware.org Cc: Paul Eggert <eggert@cs.ucla.edu> Subject: [PATCH 49/59] Remove leap-second goto from __tzfile_compute Date: Sat, 4 Jan 2025 21:57:24 -0800 Message-ID: <20250105055750.1668721-50-eggert@cs.ucla.edu> In-Reply-To: <01207110-bd60-46ae-9c08-fb39c2011067@cs.ucla.edu> References: <01207110-bd60-46ae-9c08-fb39c2011067@cs.ucla.edu> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: list Errors-To: libc-alpha-bounces~patchwork=sourceware.org@sourceware.org
Series	time: sync mktime from Gnulib \| [00/59] time: sync mktime from Gnulib [01/59] Split intprops.h into two [02/59] Support stdckdint.h internally if older GCC [03/59] Fix mishandling of default DST rule [04/59] Don't worry about !TZDEFAULT [05/59] Support static_assert in pre-C23 C [06/59] Sync mktime.c from Gnulib 2024-10-04 [07/59] Document mktime out-of-range + tm_isdst [08/59] Push tzset lock into callers of time functions [09/59] Omit parse_offset unnecessary tz == '\0' [10/59] Don’t assume TZif bloat is likely [11/59] tzset no longer calls ftello [12/59] Check TZif files more carefully [13/59] Remove alignment assumption from __tzfile_read [14/59] Treat oddball UTC offset strings as zero [15/59] Simplify __tz_compute [16/59] Improve performance in 2 BC [17/59] Don’t mishandle years < 1970 in compute_change [18/59] Match RFC 9636 names [19/59] Trivial tzset_internal speedup [20/59] Fix obscure bug when stdoffset == dstoffset [21/59] Document assumption that NO_DST == 0 [22/59] __use_tzfile is boolean [23/59] Minor tzfile.c clarity improvements [24/59] Stop using zic's -y option [25/59] Fix mishandling of default DST rule [26/59] Simplify treatment of missing and empty TZ [27/59] TZ="" always means UTC sans leap seconds [28/59] Prefer "UTC" for UTC [29/59] Simplify setting tz_rules to UTC [30/59] Update tzname etc. even if TZ is unchanged [31/59] "POSIX TZ" -> "proleptic TZ" [32/59] Reject invalid TZ strings in TZif files [33/59] Reject TZif files containing '\0' in TZ string [34/59] mktime should not consult 'daylight' [35/59] Remove __use_tzfile [36/59] Remove arbitrary limit on TZ, TZDIR lengths [37/59] Tighten setuid TZif file name check [38/59] Avoid a malloc in __tzfile_read [39/59] Free earlier in __tzfile_read [40/59] Improve __tzfile_read TZ="" comment [41/59] Refactor enum tz_rule_type [42/59] __offtime now returns struct tm [43/59] Fix overflow checking in offtime [44/59] Handle TZif time type 0 correctly [45/59] Remove invalid tzset tests from tst-bz29951.c [46/59] tzset, not localtime, now parses TZif TZ spec [47/59] Minor compute_change widening tweak [48/59] Minor SECSPERDAY widening tweak [49/59] Remove leap-second goto from __tzfile_compute [50/59] Remove use_last label from __tzfile_compute [51/59] Refactor ‘if’ in __tzfile_compute [52/59] Refactor localtime ‘if’ in __tzfile_compute [53/59] Refactor post-transition-table ‘if’ [54/59] Refactor __tzfile_compute to avoid two gotos [55/59] Refactor __tzfile_compute index local [56/59] mktime: prefer bool to int [57/59] mktime: port __mktime64 locking to Gnulib [58/59] mktime: improve tm_isdst heuristic [59/59] time: test DST adjustment for DST-less zones

Checks

Context	Check	Description
redhat-pt-bot/TryBot-apply_patch	success	Patch applied to master at the time it was sent

Commit Message

Paul Eggert Jan. 5, 2025, 5:57 a.m. UTC

  * time/tzfile.c (__tzfile_compute): Do leap second computations
first, to avoid the need for a goto and a label.
---
 time/tzfile.c | 40 +++++++++++++++++++++-------------------
 1 file changed, 21 insertions(+), 19 deletions(-)

diff mbox series

Patch

diff --git a/time/tzfile.c b/time/tzfile.c
index f86df0c8d5..e491df7d9f 100644
--- a/time/tzfile.c
+++ b/time/tzfile.c
@@ -581,6 +581,26 @@  __tzfile_compute (__time64_t timer, int use_localtime,
 {
   tzidx i;
 
+  /* Find the last leap second correction transition time before TIMER.  */
+  int corr = 0;
+  bool hit = false;
+  for (i = leapcnt; 0 < i; )
+    {
+      i--;
+      if (leaps[i].occur <= timer)
+	{
+	  /* Apply its correction.  */
+	  corr = leaps[i].corr;
+
+	  /* A hit if exactly at a positive leap second.  */
+	  hit = (timer == leaps[i].occur
+		 && (i == 0 ? 0 : leaps[i - 1].corr) < leaps[i].corr);
+	  break;
+	}
+    }
+  *leap_correct = corr;
+  *leap_hit = hit;
+
   if (use_localtime)
     {
       unsigned char ti;
@@ -609,7 +629,7 @@  __tzfile_compute (__time64_t timer, int use_localtime,
 	  /* Use the rules from the TZ string to compute the change.  */
 	  __tz_compute (timer, tp);
 
-	  goto leap;
+	  return;
 	}
       else
 	{
@@ -679,24 +699,6 @@  __tzfile_compute (__time64_t timer, int use_localtime,
 	 this is closer to what proleptic TZ does.  */
       __tzname[dst] = tm_zone;
     }
-
- leap:
-  *leap_correct = 0;
-  *leap_hit = false;
-
-  /* Find the last leap second correction transition time before TIMER.  */
-  i = leapcnt;
-  do
-    if (i-- == 0)
-      return;
-  while (timer < leaps[i].occur);
-
-  /* Apply its correction.  */
-  *leap_correct = leaps[i].corr;
-
-  if (timer == leaps[i].occur /* Exactly at the transition time.  */
-      && (leaps[i].corr > (i == 0 ? 0 : leaps[i - 1].corr)))
-    *leap_hit = true;
 }
 
 weak_alias (transitions, __libc_tzfile_freemem_ptr)