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byteswap: Rely on <stdbit.h>.

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* lib/byteswap.in.h: Include <stdbit.h>.
(_GL_BYTESWAP_HAS_BUILTIN_BSWAP16, _GL_BYTESWAP_HAS_BUILTIN_BSWAP32,
_GL_BYTESWAP_HAS_BUILTIN_BSWAP64): Remove macros.
(bswap_16): Just call stdc_memreverse8u16.
(bswap_32): Just call stdc_memreverse8u32.
(bswap_64): Just call stdc_memreverse8u64.
* modules/byteswap (Depends-on): Add stdc_memreverse8u. Remove bool.
This commit is contained in:
Bruno Haible
2026-03-15 13:30:37 +01:00
parent 56df453390
commit 7f47771c48
3 changed files with 16 additions and 50 deletions
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11
ChangeLog
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@@ -1,3 +1,14 @@
2026-03-15 Bruno Haible <bruno@clisp.org>
byteswap: Rely on <stdbit.h>.
* lib/byteswap.in.h: Include <stdbit.h>.
(_GL_BYTESWAP_HAS_BUILTIN_BSWAP16, _GL_BYTESWAP_HAS_BUILTIN_BSWAP32,
_GL_BYTESWAP_HAS_BUILTIN_BSWAP64): Remove macros.
(bswap_16): Just call stdc_memreverse8u16.
(bswap_32): Just call stdc_memreverse8u32.
(bswap_64): Just call stdc_memreverse8u64.
* modules/byteswap (Depends-on): Add stdc_memreverse8u. Remove bool.
2026-03-15 Bruno Haible <bruno@clisp.org>
stdc_load8_aligned, stdc_store8_aligned: Don't use <byteswap.h>.

53
lib/byteswap.in.h
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@@ -29,6 +29,7 @@
# define _GL_BYTESWAP_INLINE _GL_INLINE
#endif
#include <stdbit.h>
#include <stdint.h>
_GL_INLINE_HEADER_BEGIN
@@ -37,38 +38,12 @@ _GL_INLINE_HEADER_BEGIN
extern "C" {
#endif
#if __GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 8)
# define _GL_BYTESWAP_HAS_BUILTIN_BSWAP16 true
#elif defined __has_builtin
# if __has_builtin (__builtin_bswap16)
# define _GL_BYTESWAP_HAS_BUILTIN_BSWAP16 true
# endif
#endif
#if __GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 3)
# define _GL_BYTESWAP_HAS_BUILTIN_BSWAP32 true
# define _GL_BYTESWAP_HAS_BUILTIN_BSWAP64 true
#elif defined __has_builtin
# if __has_builtin (__builtin_bswap32)
# define _GL_BYTESWAP_HAS_BUILTIN_BSWAP32 true
# endif
# if __has_builtin (__builtin_bswap64)
# define _GL_BYTESWAP_HAS_BUILTIN_BSWAP64 true
# endif
#endif
/* Given an unsigned 16-bit argument X, return the value corresponding to
X with reversed byte order. */
_GL_BYTESWAP_INLINE uint_least16_t
bswap_16 (uint_least16_t x)
{
#ifdef _GL_BYTESWAP_HAS_BUILTIN_BSWAP16
return __builtin_bswap16 (x);
#else
uint_fast16_t mask = 0xff;
return ( (x & mask << 8 * 1) >> 8 * 1
| (x & mask << 8 * 0) << 8 * 1);
#endif
return stdc_memreverse8u16 (x);
}
/* Given an unsigned 32-bit argument X, return the value corresponding to
@@ -76,15 +51,7 @@ bswap_16 (uint_least16_t x)
_GL_BYTESWAP_INLINE uint_least32_t
bswap_32 (uint_least32_t x)
{
#ifdef _GL_BYTESWAP_HAS_BUILTIN_BSWAP32
return __builtin_bswap32 (x);
#else
uint_fast32_t mask = 0xff;
return ( (x & mask << 8 * 3) >> 8 * 3
| (x & mask << 8 * 2) >> 8 * 1
| (x & mask << 8 * 1) << 8 * 1
| (x & mask << 8 * 0) << 8 * 3);
#endif
return stdc_memreverse8u32 (x);
}
#ifdef UINT_LEAST64_MAX
@@ -93,19 +60,7 @@ bswap_32 (uint_least32_t x)
_GL_BYTESWAP_INLINE uint_least64_t
bswap_64 (uint_least64_t x)
{
# ifdef _GL_BYTESWAP_HAS_BUILTIN_BSWAP64
return __builtin_bswap64 (x);
# else
uint_fast64_t mask = 0xff;
return ( (x & mask << 8 * 7) >> 8 * 7
| (x & mask << 8 * 6) >> 8 * 5
| (x & mask << 8 * 5) >> 8 * 3
| (x & mask << 8 * 4) >> 8 * 1
| (x & mask << 8 * 3) << 8 * 1
| (x & mask << 8 * 2) << 8 * 3
| (x & mask << 8 * 1) << 8 * 5
| (x & mask << 8 * 0) << 8 * 7);
# endif
return stdc_memreverse8u64 (x);
}
#endif

2
modules/byteswap
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@@ -9,8 +9,8 @@ m4/byteswap.m4
Depends-on:
gen-header
extern-inline [$GL_GENERATE_BYTESWAP_H]
bool [$GL_GENERATE_BYTESWAP_H]
stdint-h [$GL_GENERATE_BYTESWAP_H]
stdc_memreverse8u [$GL_GENERATE_BYTESWAP_H]
configure.ac:
gl_BYTESWAP