Updated to fedora-glibc-20050208T0948cvs/fedora-glibc-2_3_4-6

1 files changed, 13 insertions, 4 deletions

diff --git a/timezone/tzfile.h b/timezone/tzfile.h
index 0921c3c339..0e9966a950 100644
--- a/timezone/tzfile.h
+++ b/timezone/tzfile.h
@@ -21,7 +21,7 @@
 
 #ifndef lint
 #ifndef NOID
-static char	tzfilehid[] = "@(#)tzfile.h	7.14";
+static char	tzfilehid[] = "@(#)tzfile.h	7.16";
 #endif /* !defined NOID */
 #endif /* !defined lint */
 
@@ -156,12 +156,21 @@ struct tzhead {
 #define EPOCH_YEAR	1970
 #define EPOCH_WDAY	TM_THURSDAY
 
+#define isleap(y) (((y) % 4) == 0 && (((y) % 100) != 0 || ((y) % 400) == 0))
+
 /*
-** Accurate only for the past couple of centuries;
-** that will probably do.
+** Since everything in isleap is modulo 400 (or a factor of 400), we know that
+**	isleap(y) == isleap(y % 400)
+** and so
+**	isleap(a + b) == isleap((a + b) % 400)
+** or
+**	isleap(a + b) == isleap(a % 400 + b % 400)
+** This is true even if % means modulo rather than Fortran remainder
+** (which is allowed by C89 but not C99).
+** We use this to avoid addition overflow problems.
 */
 
-#define isleap(y) (((y) % 4) == 0 && (((y) % 100) != 0 || ((y) % 400) == 0))
+#define isleap_sum(a, b)	isleap((a) % 400 + (b) % 400)
 
 #ifndef USG