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[PATCH 2/4] mktime: refactor convert_time
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From: |
Paul Eggert |
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Subject: |
[PATCH 2/4] mktime: refactor convert_time |
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Date: |
Thu, 3 Oct 2024 22:12:19 -0700 |
This is to better merge with a future version of glibc.
This merges a glibc patch by Florian Weimer in:
https://sourceware.org/pipermail/libc-alpha/2024-October/160308.html
* lib/mktime.c (convert_time): Accept a boolean flag instead
of a function pointer. All callers changed.
---
ChangeLog | 9 ++++++
lib/mktime-internal.h | 9 +++---
lib/mktime.c | 71 ++++++++++++++++++++++---------------------
lib/timegm.c | 2 +-
4 files changed, 50 insertions(+), 41 deletions(-)
diff --git a/ChangeLog b/ChangeLog
index 22a40c3d58..08a452130d 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,12 @@
+2024-10-03 Paul Eggert <eggert@cs.ucla.edu>
+
+ mktime: refactor convert_time
+ This is to better merge with a future version of glibc.
+ This merges a glibc patch by Florian Weimer in:
+ https://sourceware.org/pipermail/libc-alpha/2024-October/160308.html
+ * lib/mktime.c (convert_time): Accept a boolean flag instead
+ of a function pointer. All callers changed.
+
2024-10-03 Bruno Haible <bruno@clisp.org>
bcp47: Add tests.
diff --git a/lib/mktime-internal.h b/lib/mktime-internal.h
index 0693aaf140..3e2848c121 100644
--- a/lib/mktime-internal.h
+++ b/lib/mktime-internal.h
@@ -71,9 +71,8 @@ typedef int mktime_offset_t;
#endif
/* Subroutine of mktime. Return the time_t representation of TP and
- normalize TP, given that a struct tm * maps to a time_t as performed
- by FUNC. Record next guess for localtime-gmtime offset in *OFFSET. */
-extern __time64_t __mktime_internal (struct tm *tp,
- struct tm *(*func) (__time64_t const *,
- struct tm *),
+ normalize TP, given that a struct tm * maps to a time_t. If
+ LOCAL, the mapping is performed by localtime_r, otherwise by gmtime_r.
+ Record next guess for localtime-gmtime offset in *OFFSET. */
+extern __time64_t __mktime_internal (struct tm *tp, bool local,
mktime_offset_t *offset) attribute_hidden;
diff --git a/lib/mktime.c b/lib/mktime.c
index 744a7277bb..92ac9735b0 100644
--- a/lib/mktime.c
+++ b/lib/mktime.c
@@ -251,29 +251,31 @@ tm_diff (long_int year, long_int yday, int hour, int min,
int sec,
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 __time64_t. Return TM if successful, NULL (setting errno) on
- failure. */
+/* Convert T to a struct tm value in *TM. Use localtime64_r if LOCAL,
+ otherwise gmtime64_r. T must be in range for __time64_t. Return
+ TM if successful, NULL (setting errno) on failure. */
static struct tm *
-convert_time (struct tm *(*convert) (const __time64_t *, struct tm *),
- long_int t, struct tm *tm)
+convert_time (bool local, long_int t, struct tm *tm)
{
__time64_t x = t;
- return convert (&x, tm);
+ if (local)
+ return __localtime64_r (&x, tm);
+ else
+ return __gmtime64_r (&x, 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 __time64_t and long_int.
- Return TP on success, NULL (setting errno) on failure. */
+/* Convert *T to a broken down time in *TP (as if by localtime if
+ LOCAL, otherwise as if by gmtime). 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
+ __time64_t and long_int. Return TP on success, NULL (setting
+ errno) on failure. */
static struct tm *
-ranged_convert (struct tm *(*convert) (const __time64_t *, struct tm *),
- long_int *t, struct tm *tp)
+ranged_convert (bool local, long_int *t, struct tm *tp)
{
long_int t1 = (*t < mktime_min ? mktime_min
: *t <= mktime_max ? *t : mktime_max);
- struct tm *r = convert_time (convert, t1, tp);
+ struct tm *r = convert_time (local, t1, tp);
if (r)
{
*t = t1;
@@ -294,7 +296,7 @@ ranged_convert (struct tm *(*convert) (const __time64_t *,
struct tm *),
long_int mid = long_int_avg (ok, bad);
if (mid == ok || mid == bad)
break;
- if (convert_time (convert, mid, tp))
+ if (convert_time (local, mid, tp))
ok = mid, oktm = *tp;
else if (errno != EOVERFLOW)
return NULL;
@@ -310,29 +312,28 @@ ranged_convert (struct tm *(*convert) (const __time64_t
*, struct tm *),
}
-/* Convert *TP to a __time64_t value, inverting
- the monotonic and mostly-unit-linear conversion function CONVERT.
- Use *OFFSET to keep track of a guess at the offset of the result,
+/* Convert *TP to a __time64_t value. If LOCAL, the reverse mapping
+ is performed as if localtime, otherwise as if by gmtime. 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;
+ If *OFFSET's guess is correct, only one reverse mapping 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. */
__time64_t
-__mktime_internal (struct tm *tp,
- struct tm *(*convert) (const __time64_t *, struct tm *),
- mktime_offset_t *offset)
+__mktime_internal (struct tm *tp, bool local, mktime_offset_t *offset)
{
struct tm tm;
- /* The maximum number of probes (calls to CONVERT) should be enough
- to handle any combinations of time zone rule changes, solar time,
- leap seconds, and oscillations around a spring-forward gap.
- POSIX.1 prohibits leap seconds, but some hosts have them anyway. */
+ /* The maximum number of probes should be enough to handle any
+ combinations of time zone rule changes, solar time, leap seconds,
+ and oscillations around a spring-forward gap. POSIX.1 prohibits
+ leap seconds, but some hosts have them anyway. */
int remaining_probes = 6;
- /* Time requested. Copy it in case CONVERT modifies *TP; this can
- occur if TP is localtime's returned value and CONVERT is localtime. */
+ /* Time requested. Copy it in case gmtime/localtime modify *TP;
+ this can occur if TP is localtime's returned value and CONVERT is
+ localtime. */
int sec = tp->tm_sec;
int min = tp->tm_min;
int hour = tp->tm_hour;
@@ -390,7 +391,7 @@ __mktime_internal (struct tm *tp,
while (true)
{
- if (! ranged_convert (convert, &t, &tm))
+ if (! ranged_convert (local, &t, &tm))
return -1;
long_int dt = tm_diff (year, yday, hour, min, sec, &tm);
if (dt == 0)
@@ -469,7 +470,7 @@ __mktime_internal (struct tm *tp,
if (! ckd_add (&ot, t, delta * direction))
{
struct tm otm;
- if (! ranged_convert (convert, &ot, &otm))
+ if (! ranged_convert (local, &ot, &otm))
return -1;
if (! isdst_differ (isdst, otm.tm_isdst))
{
@@ -479,7 +480,7 @@ __mktime_internal (struct tm *tp,
&otm);
if (mktime_min <= gt && gt <= mktime_max)
{
- if (convert_time (convert, gt, &tm))
+ if (convert_time (local, gt, &tm))
{
t = gt;
goto offset_found;
@@ -493,7 +494,7 @@ __mktime_internal (struct tm *tp,
/* No unusual DST offset was found nearby. Assume one-hour DST. */
t += 60 * 60 * dst_difference;
- if (mktime_min <= t && t <= mktime_max && convert_time (convert, t, &tm))
+ if (mktime_min <= t && t <= mktime_max && convert_time (local, t, &tm))
goto offset_found;
__set_errno (EOVERFLOW);
@@ -520,7 +521,7 @@ __mktime_internal (struct tm *tp,
__set_errno (EOVERFLOW);
return -1;
}
- if (! convert_time (convert, t, &tm))
+ if (! convert_time (local, t, &tm))
return -1;
}
@@ -542,7 +543,7 @@ __mktime64 (struct tm *tp)
# if defined _LIBC || NEED_MKTIME_WORKING
static mktime_offset_t localtime_offset;
- return __mktime_internal (tp, __localtime64_r, &localtime_offset);
+ return __mktime_internal (tp, true, &localtime_offset);
# else
# undef mktime
return mktime (tp);
diff --git a/lib/timegm.c b/lib/timegm.c
index e5cf30c019..1f1f66c61b 100644
--- a/lib/timegm.c
+++ b/lib/timegm.c
@@ -31,7 +31,7 @@ __timegm64 (struct tm *tmp)
{
static mktime_offset_t gmtime_offset;
tmp->tm_isdst = 0;
- return __mktime_internal (tmp, __gmtime64_r, &gmtime_offset);
+ return __mktime_internal (tmp, false, &gmtime_offset);
}
#if defined _LIBC && __TIMESIZE != 64
--
2.43.0