[PATCH] Cygwin: define byteswap.h inlines as macros

Václav Haisman vhaisman@gmail.com
Tue Mar 15 10:55:00 GMT 2016


On 15 March 2016 at 04:13, Yaakov Selkowitz <yselkowi@redhat.com> wrote:
> The bswap_* "functions" are macros in glibc, so they may be tested for
> by the preprocessor (e.g. #ifdef bswap_16).
>
> Signed-off-by: Yaakov Selkowitz <yselkowi@redhat.com>
> ---
>  winsup/cygwin/include/byteswap.h | 14 +++++++++-----
>  1 file changed, 9 insertions(+), 5 deletions(-)
>
> diff --git a/winsup/cygwin/include/byteswap.h b/winsup/cygwin/include/byteswap.h
> index cd5a726..9f73c5a 100644
> --- a/winsup/cygwin/include/byteswap.h
> +++ b/winsup/cygwin/include/byteswap.h
> @@ -16,23 +16,27 @@ extern "C" {
>  #endif
>
>  static __inline unsigned short
> -bswap_16 (unsigned short __x)
> +__bswap_16 (unsigned short __x)
>  {
>    return (__x >> 8) | (__x << 8);
>  }
>
>  static __inline unsigned int
> -bswap_32 (unsigned int __x)
> +__bswap_32 (unsigned int __x)
>  {
> -  return (bswap_16 (__x & 0xffff) << 16) | (bswap_16 (__x >> 16));
> +  return (__bswap_16 (__x & 0xffff) << 16) | (__bswap_16 (__x >> 16));
>  }
>
>  static __inline unsigned long long
> -bswap_64 (unsigned long long __x)
> +__bswap_64 (unsigned long long __x)
>  {
> -  return (((unsigned long long) bswap_32 (__x & 0xffffffffull)) << 32) | (bswap_32 (__x >> 32));
> +  return (((unsigned long long) __bswap_32 (__x & 0xffffffffull)) << 32) | (__bswap_32 (__x >> 32));
>  }
>
> +#define bswap_16(x) __bswap_16(x)
> +#define bswap_32(x) __bswap_32(x)
> +#define bswap_64(x) __bswap_64(x)
> +
>  #ifdef __cplusplus
>  }
>  #endif
> --
> 2.7.0
>

Would it not be better to leave the original functions as they were
and simply use these defines?

#define bswap_16 bswap_16
#define bswap_32 bswap_32
#define bswap_64 bswap_64

I believe this is valid C and C++. Untested.

-- 
VH

On 15 March 2016 at 04:13, Yaakov Selkowitz <yselkowi@redhat.com> wrote:
> The bswap_* "functions" are macros in glibc, so they may be tested for
> by the preprocessor (e.g. #ifdef bswap_16).
>
> Signed-off-by: Yaakov Selkowitz <yselkowi@redhat.com>
> ---
>  winsup/cygwin/include/byteswap.h | 14 +++++++++-----
>  1 file changed, 9 insertions(+), 5 deletions(-)
>
> diff --git a/winsup/cygwin/include/byteswap.h b/winsup/cygwin/include/byteswap.h
> index cd5a726..9f73c5a 100644
> --- a/winsup/cygwin/include/byteswap.h
> +++ b/winsup/cygwin/include/byteswap.h
> @@ -16,23 +16,27 @@ extern "C" {
>  #endif
>
>  static __inline unsigned short
> -bswap_16 (unsigned short __x)
> +__bswap_16 (unsigned short __x)
>  {
>    return (__x >> 8) | (__x << 8);
>  }
>
>  static __inline unsigned int
> -bswap_32 (unsigned int __x)
> +__bswap_32 (unsigned int __x)
>  {
> -  return (bswap_16 (__x & 0xffff) << 16) | (bswap_16 (__x >> 16));
> +  return (__bswap_16 (__x & 0xffff) << 16) | (__bswap_16 (__x >> 16));
>  }
>
>  static __inline unsigned long long
> -bswap_64 (unsigned long long __x)
> +__bswap_64 (unsigned long long __x)
>  {
> -  return (((unsigned long long) bswap_32 (__x & 0xffffffffull)) << 32) | (bswap_32 (__x >> 32));
> +  return (((unsigned long long) __bswap_32 (__x & 0xffffffffull)) << 32) | (__bswap_32 (__x >> 32));
>  }
>
> +#define bswap_16(x) __bswap_16(x)
> +#define bswap_32(x) __bswap_32(x)
> +#define bswap_64(x) __bswap_64(x)
> +
>  #ifdef __cplusplus
>  }
>  #endif
> --
> 2.7.0
>



-- 
VH



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