Commit e30056275c2a6d857d004d850658ccf3490a7876
2010-10-12T19:11:51
bswap.h: Add ntohs() and htons() functions Since commit 70aab459, the msvc and MinGW builds have relied on the built-in implementation of ntohl() and htonl(), rather than linking the wsock32 library. The new index manipulation code now calls ntohs()/htons() in addition to ntohl()/htonl(), so we need to provide a built-in implementation of the 16-bit functions. Signed-off-by: Ramsay Jones <ramsay@ramsay1.demon.co.uk>
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diff --git a/src/bswap.h b/src/bswap.h
index b3e8a0a..b9211c3 100644
--- a/src/bswap.h
+++ b/src/bswap.h
@@ -21,7 +21,15 @@ GIT_INLINE(uint32_t) default_swab32(uint32_t val)
#undef bswap32
-#if defined(__GNUC__) && (defined(__i386__) || defined(__x86_64__))
+GIT_INLINE(uint16_t) default_swab16(uint16_t val)
+{
+ return (((val & 0xff00) >> 8) |
+ ((val & 0x00ff) << 8));
+}
+
+#undef bswap16
+
+#if defined(__GNUC__) && defined(__i386__)
#define bswap32(x) ({ \
uint32_t __res; \
@@ -32,11 +40,41 @@ GIT_INLINE(uint32_t) default_swab32(uint32_t val)
} \
__res; })
+#define bswap16(x) ({ \
+ uint16_t __res; \
+ if (__builtin_constant_p(x)) { \
+ __res = default_swab16(x); \
+ } else { \
+ __asm__("xchgb %b0,%h0" : "=q" (__res) : "0" ((uint16_t)(x))); \
+ } \
+ __res; })
+
+#elif defined(__GNUC__) && defined(__x86_64__)
+
+#define bswap32(x) ({ \
+ uint32_t __res; \
+ if (__builtin_constant_p(x)) { \
+ __res = default_swab32(x); \
+ } else { \
+ __asm__("bswapl %0" : "=r" (__res) : "0" ((uint32_t)(x))); \
+ } \
+ __res; })
+
+#define bswap16(x) ({ \
+ uint16_t __res; \
+ if (__builtin_constant_p(x)) { \
+ __res = default_swab16(x); \
+ } else { \
+ __asm__("xchgb %b0,%h0" : "=Q" (__res) : "0" ((uint16_t)(x))); \
+ } \
+ __res; })
+
#elif defined(_MSC_VER) && (defined(_M_IX86) || defined(_M_X64))
#include <stdlib.h>
#define bswap32(x) _byteswap_ulong(x)
+#define bswap16(x) _byteswap_ushort(x)
#endif
@@ -48,3 +86,12 @@ GIT_INLINE(uint32_t) default_swab32(uint32_t val)
#define htonl(x) bswap32(x)
#endif
+
+#ifdef bswap16
+
+#undef ntohs
+#undef htons
+#define ntohs(x) bswap16(x)
+#define htons(x) bswap16(x)
+
+#endif