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authorRoland McGrath <roland@gnu.org>2005-09-08 08:09:16 +0000
committerRoland McGrath <roland@gnu.org>2005-09-08 08:09:16 +0000
commit4043787150772987ca8e377b2d488dae6b5d8a8b (patch)
tree55b26a885bc155d84696c8dc2a68b064a25d1068 /time/mktime.c
parentca8572295742314989e0a6e3d4a10cbae1958e8a (diff)
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[BZ #1033, BZ #1061]
2005-07-11 Derek R. Price <derek@ximbiot.com> [BZ #1061] * sysdeps/generic/glob.c (glob): Only a 0 return from getlogin_r means success, according to POSIX 1003.2. 2005-06-23 Paul Eggert <eggert@cs.ucla.edu> [BZ #1033] * time/mktime.c: Import from gnulib. The following macros are now consistent with other gnulib code. This does not change mktime's behavior. (TYPE_IS_INTEGER): New macro. (time_t_is_integer): Use it. (TYPE_TWOS_COMPLEMENT): New macro. (twos_complement_arithmetic): Use it. (TYPE_ONES_COMPLEMENT): New macro. (TYPE_MINIMUM, TYPE_MAXIMUM): Now supports signed-magnitude. mktime doesn't use this, but the code now matches other gnulib code. (ranged_convert): Pacify GCC 4.0 in a different way, which generates a few bytes less code. (ranged_convert, __mktime_internal): When calling a function via a pointer P, use P () rather than (*P) (), as we now assume C89 or better.
Diffstat (limited to 'time/mktime.c')
-rw-r--r--time/mktime.c60
1 files changed, 40 insertions, 20 deletions
diff --git a/time/mktime.c b/time/mktime.c
index 258eec6..5a326d1 100644
--- a/time/mktime.c
+++ b/time/mktime.c
@@ -62,13 +62,38 @@
? (a) >> (b) \
: (a) / (1 << (b)) - ((a) % (1 << (b)) < 0))
-/* The extra casts work around common compiler bugs. */
+/* The extra casts in the following macros work around compiler bugs,
+ e.g., in Cray C 5.0.3.0. */
+
+/* True if the arithmetic type T is an integer type. bool counts as
+ an integer. */
+#define TYPE_IS_INTEGER(t) ((t) 1.5 == 1)
+
+/* True if negative values of the signed integer type T use two's
+ complement, ones' complement, or signed magnitude representation,
+ respectively. Much GNU code assumes two's complement, but some
+ people like to be portable to all possible C hosts. */
+#define TYPE_TWOS_COMPLEMENT(t) ((t) ~ (t) 0 == (t) -1)
+#define TYPE_ONES_COMPLEMENT(t) ((t) ~ (t) 0 == 0)
+#define TYPE_SIGNED_MAGNITUDE(t) ((t) ~ (t) 0 < (t) -1)
+
+/* True if the arithmetic type T is signed. */
#define TYPE_SIGNED(t) (! ((t) 0 < (t) -1))
-/* The outer cast is needed to work around a bug in Cray C 5.0.3.0.
- It is necessary at least when t == time_t. */
-#define TYPE_MINIMUM(t) ((t) (TYPE_SIGNED (t) \
- ? ~ (t) 0 << (sizeof (t) * CHAR_BIT - 1) : (t) 0))
-#define TYPE_MAXIMUM(t) ((t) (~ (t) 0 - TYPE_MINIMUM (t)))
+
+/* The maximum and minimum values for the integer type T. These
+ macros have undefined behavior if T is signed and has padding bits.
+ If this is a problem for you, please let us know how to fix it for
+ your host. */
+#define TYPE_MINIMUM(t) \
+ ((t) (! TYPE_SIGNED (t) \
+ ? (t) 0 \
+ : TYPE_SIGNED_MAGNITUDE (t) \
+ ? ~ (t) 0 \
+ : ~ (t) 0 << (sizeof (t) * CHAR_BIT - 1)))
+#define TYPE_MAXIMUM(t) \
+ ((t) (! TYPE_SIGNED (t) \
+ ? (t) -1 \
+ : ~ (~ (t) 0 << (sizeof (t) * CHAR_BIT - 1))))
#ifndef TIME_T_MIN
# define TIME_T_MIN TYPE_MINIMUM (time_t)
@@ -81,8 +106,8 @@
/* Verify a requirement at compile-time (unlike assert, which is runtime). */
#define verify(name, assertion) struct name { char a[(assertion) ? 1 : -1]; }
-verify (time_t_is_integer, (time_t) 0.5 == 0);
-verify (twos_complement_arithmetic, -1 == ~1 + 1);
+verify (time_t_is_integer, TYPE_IS_INTEGER (time_t));
+verify (twos_complement_arithmetic, TYPE_TWOS_COMPLEMENT (int));
/* The code also assumes that signed integer overflow silently wraps
around, but this assumption can't be stated without causing a
diagnostic on some hosts. */
@@ -204,14 +229,12 @@ static struct tm *
ranged_convert (struct tm *(*convert) (const time_t *, struct tm *),
time_t *t, struct tm *tp)
{
- struct tm *r;
+ struct tm *r = convert (t, tp);
- if (! (r = (*convert) (t, tp)) && *t)
+ if (!r && *t)
{
time_t bad = *t;
time_t ok = 0;
- /* Initialize to make the compiler happy. */
- struct tm tm = { 0, };
/* BAD is a known unconvertible time_t, and OK is a known good one.
Use binary search to narrow the range between BAD and OK until
@@ -221,11 +244,9 @@ ranged_convert (struct tm *(*convert) (const time_t *, struct tm *),
time_t mid = *t = (bad < 0
? bad + ((ok - bad) >> 1)
: ok + ((bad - ok) >> 1));
- if ((r = (*convert) (t, tp)))
- {
- tm = *r;
- ok = mid;
- }
+ r = convert (t, tp);
+ if (r)
+ ok = mid;
else
bad = mid;
}
@@ -235,8 +256,7 @@ ranged_convert (struct tm *(*convert) (const time_t *, struct tm *),
/* The last conversion attempt failed;
revert to the most recent successful attempt. */
*t = ok;
- *tp = tm;
- r = tp;
+ r = convert (t, tp);
}
}
@@ -465,7 +485,7 @@ __mktime_internal (struct tm *tp,
t2 = t1 + sec_adjustment;
if (((t1 < t) != (sec_requested < 0))
| ((t2 < t1) != (sec_adjustment < 0))
- | ! (*convert) (&t2, &tm))
+ | ! convert (&t2, &tm))
return -1;
t = t2;
}