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authorLibravatar Junio C Hamano <gitster@pobox.com>2011-07-06 15:38:18 -0700
committerLibravatar Junio C Hamano <gitster@pobox.com>2011-07-06 15:38:18 -0700
commit71ee7fd15457a0252c089420b5b66de266dcbd2f (patch)
tree98d4d7d1f72c30fd7695f011be78d3e45158c41a /compat/bswap.h
parentMerge commit 'v1.6.0' into jc/checkout-reflog-fix (diff)
parentGit 1.7.0 (diff)
downloadtgif-71ee7fd15457a0252c089420b5b66de266dcbd2f.tar.xz
Merge commit 'v1.7.0' into jc/checkout-reflog-fix
* commit 'v1.7.0': (4188 commits) Git 1.7.0 Fix typo in 1.6.6.2 release notes Re-fix check-ref-format documentation mark-up archive documentation: attributes are taken from the tree by default Documentation: minor fixes to RelNotes-1.7.0 bash: support 'git am's new '--continue' option filter-branch: Fix error message for --prune-empty --commit-filter am: switch --resolved to --continue Update draft release notes to 1.7.0 one more time Git 1.6.6.2 t8003: check exit code of command and error message separately check-ref-format documentation: fix enumeration mark-up Documentation: quote braces in {upstream} notation t3902: Protect against OS X normalization blame: prevent a segv when -L given start > EOF git-push: document all the status flags used in the output Fix parsing of imap.preformattedHTML and imap.sslverify git-add documentation: Fix shell quoting example Revert "pack-objects: fix pack generation when using pack_size_limit" archive: simplify archive format guessing ...
Diffstat (limited to 'compat/bswap.h')
-rw-r--r--compat/bswap.h46
1 files changed, 46 insertions, 0 deletions
diff --git a/compat/bswap.h b/compat/bswap.h
new file mode 100644
index 0000000000..f3b8c44181
--- /dev/null
+++ b/compat/bswap.h
@@ -0,0 +1,46 @@
+/*
+ * Let's make sure we always have a sane definition for ntohl()/htonl().
+ * Some libraries define those as a function call, just to perform byte
+ * shifting, bringing significant overhead to what should be a simple
+ * operation.
+ */
+
+/*
+ * Default version that the compiler ought to optimize properly with
+ * constant values.
+ */
+static inline uint32_t default_swab32(uint32_t val)
+{
+ return (((val & 0xff000000) >> 24) |
+ ((val & 0x00ff0000) >> 8) |
+ ((val & 0x0000ff00) << 8) |
+ ((val & 0x000000ff) << 24));
+}
+
+#if defined(__GNUC__) && (defined(__i386__) || defined(__x86_64__))
+
+#define bswap32(x) ({ \
+ uint32_t __res; \
+ if (__builtin_constant_p(x)) { \
+ __res = default_swab32(x); \
+ } else { \
+ __asm__("bswap %0" : "=r" (__res) : "0" ((uint32_t)(x))); \
+ } \
+ __res; })
+
+#elif defined(_MSC_VER) && (defined(_M_IX86) || defined(_M_X64))
+
+#include <stdlib.h>
+
+#define bswap32(x) _byteswap_ulong(x)
+
+#endif
+
+#ifdef bswap32
+
+#undef ntohl
+#undef htonl
+#define ntohl(x) bswap32(x)
+#define htonl(x) bswap32(x)
+
+#endif