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| author | Nicolas Pitre <nico@cam.org> | 2007-04-09 01:06:29 -0400 |
|---|---|---|
| committer | Junio C Hamano <junkio@cox.net> | 2007-04-10 12:48:14 -0700 |
| commit | 8723f216263ba4a0f06be7b93fada863c0931e09 (patch) | |
| tree | 6d357724c891ce009a8c7ae1a0a4083bc39ff1f5 /git-compat-util.h | |
| parent | 57059091fad25427bce9b3d47e073ce0518d164b (diff) | |
| download | git-8723f216263ba4a0f06be7b93fada863c0931e09.tar.gz git-8723f216263ba4a0f06be7b93fada863c0931e09.tar.xz | |
make overflow test on delta base offset work regardless of variable size
This patch introduces the MSB() macro to obtain the desired number of
most significant bits from a given variable independently of the variable
type.
It is then used to better implement the overflow test on the OBJ_OFS_DELTA
base offset variable with the property of always working correctly
regardless of the type/size of that variable.
Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
Diffstat (limited to 'git-compat-util.h')
| -rw-r--r-- | git-compat-util.h | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/git-compat-util.h b/git-compat-util.h index 139fc1910..bcfcb35ec 100644 --- a/git-compat-util.h +++ b/git-compat-util.h @@ -13,6 +13,14 @@ #define ARRAY_SIZE(x) (sizeof(x)/sizeof(x[0])) +#ifdef __GNUC__ +#define TYPEOF(x) (__typeof__(x)) +#else +#define TYPEOF(x) +#endif + +#define MSB(x, bits) ((x) & TYPEOF(x)(~0ULL << (sizeof(x) * 8 - (bits)))) + #if !defined(__APPLE__) && !defined(__FreeBSD__) #define _XOPEN_SOURCE 600 /* glibc2 and AIX 5.3L need 500, OpenBSD needs 600 for S_ISLNK() */ #define _XOPEN_SOURCE_EXTENDED 1 /* AIX 5.3L needs this */ |