[PATCH xserver] Add unit tests for the byte swapping macros.

[Peter Hutterer]

On Tue, Mar 28, 2017 at 01:17:21PM -0700, Eric Anholt wrote:
> Peter noted a weirdness in my new bswap code, which could use some
> tests to justify it.
> 
> Signed-off-by: Eric Anholt <eric at anholt.net>

Reviewed-by: Peter Hutterer <peter.hutterer at who-t.net>

thanks

Cheers,
   Peter
> ---
>  test/misc.c | 43 +++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 43 insertions(+)
> 
> diff --git a/test/misc.c b/test/misc.c
> index ae46ccccbab9..c10a2b935bc4 100644
> --- a/test/misc.c
> +++ b/test/misc.c
> @@ -192,6 +192,48 @@ dix_request_size_checks(void)
>      assert(rc == Success);
>  }
>  
> +static void
> +bswap_test(void)
> +{
> +    const uint16_t test_16 = 0xaabb;
> +    const uint16_t expect_16 = 0xbbaa;
> +    const uint32_t test_32 = 0xaabbccdd;
> +    const uint32_t expect_32 = 0xddccbbaa;
> +    const uint64_t test_64 = 0x11223344aabbccddull;
> +    const uint64_t expect_64 = 0xddccbbaa44332211ull;
> +    uint16_t result_16;
> +    uint32_t result_32;
> +    uint64_t result_64;
> +    unsigned buffer[sizeof(test_64) + 4];
> +    void *unaligned = &buffer[1];
> +
> +    assert(bswap_16(test_16) == expect_16);
> +    assert(bswap_32(test_32) == expect_32);
> +    assert(bswap_64(test_64) == expect_64);
> +
> +    /* Test the swapping-in-a-pointer functions, with unaligned
> +     * addresses (the functions shouldn't cause traps in that case).
> +     */
> +    for (int i = 0; i < 2; i++) {
> +        unaligned = buffer + i;
> +        if (((uintptr_t)unaligned & 1) == 1)
> +            break;
> +    }
> +    memcpy(unaligned, &test_16, sizeof(test_16));
> +    swaps((uint16_t *)unaligned);
> +    memcpy(&result_16, unaligned, sizeof(result_16));
> +    assert(result_16 == expect_16);
> +
> +    memcpy(unaligned, &test_32, sizeof(test_32));
> +    swapl((uint32_t *)unaligned);
> +    memcpy(&result_32, unaligned, sizeof(result_32));
> +    assert(result_32 == expect_32);
> +
> +    memcpy(unaligned, &test_64, sizeof(test_64));
> +    swapll((uint64_t *)unaligned);
> +    memcpy(&result_64, unaligned, sizeof(result_64));
> +    assert(result_64 == expect_64);
> +}
>  
>  int
>  misc_test(void)
> @@ -199,6 +241,7 @@ misc_test(void)
>      dix_version_compare();
>      dix_update_desktop_dimensions();
>      dix_request_size_checks();
> +    bswap_test();
>  
>      return 0;
>  }
> -- 
> 2.11.0
> 
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