Diego Biurrun <[email protected]> writes:

> User-provided data should never trigger an assert; also fix an instance of
> get_bits where get_bits_long should have been used. This fixes the warning:
> libavcodec/vaapi_mpeg2.c:112:14: warning: variable 'start_code' set but not 
> used
> ---
>  libavcodec/vaapi_mpeg2.c |    5 +++--
>  1 files changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/libavcodec/vaapi_mpeg2.c b/libavcodec/vaapi_mpeg2.c
> index 561f4bf..5da873e 100644
> --- a/libavcodec/vaapi_mpeg2.c
> +++ b/libavcodec/vaapi_mpeg2.c
> @@ -115,8 +115,9 @@ static int vaapi_mpeg2_decode_slice(AVCodecContext 
> *avctx, const uint8_t *buffer
>
>      /* Determine macroblock_offset */
>      init_get_bits(&gb, buffer, 8 * size);
> -    start_code = get_bits(&gb, 32);
> -    assert((start_code & 0xffffff00) == 0x00000100);
> +    start_code = get_bits_long(&gb, 32);
> +    if (!((start_code & 0xffffff00) == 0x00000100))
> +        return AVERROR_INVALIDDATA;
>      quantiser_scale_code = get_bits(&gb, 5);
>      intra_slice_flag = get_bits1(&gb);
>      if (intra_slice_flag) {
> -- 

if (foo != bar) is much nicer than if (!(foo == bar)), don't you think?

BTW, if (start_code >> 8 != 1) is another way of writing this.

-- 
Måns Rullgård
[email protected]
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