[PATCH 4/8] Introduce swap_uint{16, 32} functions, used in swap{l, s}

[Aaron Plattner]

On 08/16/2011 07:58 PM, Matt Turner wrote:
> Signed-off-by: Matt Turner<mattst88 at gmail.com>
> ---
>   include/misc.h |   30 ++++++++++++++++++++----------
>   1 files changed, 20 insertions(+), 10 deletions(-)
> 
> diff --git a/include/misc.h b/include/misc.h
> index d991c0a..6034c72 100644
> --- a/include/misc.h
> +++ b/include/misc.h
> @@ -259,20 +259,30 @@ version_compare(uint16_t a_major, uint16_t a_minor,
>       SwapLongs((CARD32 *)(stuff + 1), LengthRestL(stuff))
> 
>   /* byte swap a 32-bit value */
> +static inline void swap_uint32(uint32_t *x)
> +{
> +	char n = ((char *)&x)[0];
> +	((char *) x)[0] = ((char *) x)[3];
> +	((char *) x)[3] = n;
> +	n = ((char *) x)[1];
> +	((char *) x)[1] = ((char *) x)[2];
> +	((char *) x)[2] = n;
> +}
> +
>   #define swapl(x) do { \
> -		 char n = ((char *) (x))[0];\
> -		 ((char *) (x))[0] = ((char *) (x))[3];\
> -		 ((char *) (x))[3] = n;\
> -		 n = ((char *) (x))[1];\
> -		 ((char *) (x))[1] = ((char *) (x))[2];\
> -		 ((char *) (x))[2] = n;\
> +		swap_uint32((uint32_t *)(x)); \
>   	} while (0)
> 
> -/* byte swap a short */
> +/* byte swap a 16-bit value */
> +static inline void swap_uint16(uint16_t *x)
> +{
> +	char  n = ((char *) x)[0];
> +	((char *) x)[0] = ((char *) x)[1];
> +	((char *) x)[1] = n;
> +}
> +
>   #define swaps(x) do { \
> -		 char  n = ((char *) (x))[0];\
> -		 ((char *) (x))[0] = ((char *) (x))[1];\
> -		 ((char *) (x))[1] = n;\
> +		swap_uint16((uint16_t *)(x)); \
>   	} while (0)
> 
>   /* copy 32-bit value from src to dst byteswapping on the way */

This change (commit 893e86a49e3e381cff48a9e86dc2d9b3d5431d95) caused an XTS regression:

400|0 1 1 12:42:31|IC Start
200|0 1 12:42:31|TP Start
520|0 1 00012000 1 1|VSW5TESTSUITE PURPOSE 1
520|0 1 00012000 1 2|Assertion AllocColor-1.(A)
520|0 1 00012000 1 3|When a client sends a valid AllocColor protocol request to
520|0 1 00012000 1 4|the X server, then the X server sends back a reply to the
520|0 1 00012000 1 5|client with the minimum required length.
520|0 1 00012000 1 6|METH: Call library function testfunc() to do the following:
520|0 1 00012000 1 7|METH: Open a connection to the X server using native byte sex.
520|0 1 00012000 1 8|METH: Create colourmap with alloc set to AllocNone.
520|0 1 00012000 1 9|METH: Send a valid AllocColor protocol request to the X server.
520|0 1 00012000 1 10|METH: Verify that the X server sends back a reply.
520|0 1 00012000 1 11|METH: Open a connection to the X server using reversed byte sex.
520|0 1 00012000 1 12|METH: Create colourmap with alloc set to AllocNone.
520|0 1 00012000 1 13|METH: Send a valid AllocColor protocol request to the X server.
520|0 1 00012000 1 14|METH: Verify that the X server sends back a reply.
520|0 1 00012004 1 1|REPORT: Expect: wanted NOTHING, got ERROR - BadIDChoice
520|0 1 00012004 1 2|REPORT: Expect: wanted NOTHING, got ERROR - BadIDChoice
520|0 1 00012004 1 3|REPORT: Expect: wanted REPLY - X_AllocColor , got ERROR - BadColor
520|0 1 00012004 1 4|REPORT: client 0 failed to receive AllocColor reply
520|0 1 00012004 1 5|REPORT: Test AllocColor unresolved with 2 reasons.
220|0 1 2 12:42:31|UNRESOLVED
410|0 1 1 12:42:31|IC End