[FFmpeg-devel] [PATCH] avcodec/dca: remove GetBitContext usage from avpriv_dca_parse_core_frame_header()

[James Almer]

On 7/19/2017 4:43 PM, James Almer wrote:
> This prevents potential ABI issues with GetBitContext.
> 
> Signed-off-by: James Almer <jamrial at gmail.com>
> ---
>  libavcodec/dca.c        | 12 +++++++++++-
>  libavcodec/dca.h        |  7 +++++--
>  libavcodec/dca_core.c   |  2 +-
>  libavcodec/dca_parser.c |  4 +---
>  libavformat/dtsdec.c    |  4 +---
>  5 files changed, 19 insertions(+), 10 deletions(-)
> 
> diff --git a/libavcodec/dca.c b/libavcodec/dca.c
> index 39f8f3d81c..307b21471e 100644
> --- a/libavcodec/dca.c
> +++ b/libavcodec/dca.c
> @@ -88,7 +88,7 @@ int avpriv_dca_convert_bitstream(const uint8_t *src, int src_size, uint8_t *dst,
>      }
>  }
>  
> -int avpriv_dca_parse_core_frame_header(GetBitContext *gb, DCACoreFrameHeader *h)
> +int ff_dca_parse_core_frame_header(DCACoreFrameHeader *h, GetBitContext *gb)
>  {
>      if (get_bits_long(gb, 32) != DCA_SYNCWORD_CORE_BE)
>          return DCA_PARSE_ERROR_SYNC_WORD;
> @@ -145,3 +145,13 @@ int avpriv_dca_parse_core_frame_header(GetBitContext *gb, DCACoreFrameHeader *h)
>      h->dn_code = get_bits(gb, 4);
>      return 0;
>  }
> +
> +int avpriv_dca_parse_core_frame_header(DCACoreFrameHeader *h, uint8_t *buf, int size)
> +{
> +    GetBitContext gb;
> +
> +    if (init_get_bits8(&gb, buf, size) < 0)
> +        return DCA_PARSE_ERROR_INVALIDDATA;
> +
> +    return ff_dca_parse_core_frame_header(h, &gb);
> +}
> diff --git a/libavcodec/dca.h b/libavcodec/dca.h
> index cf6204e554..172c965b3b 100644
> --- a/libavcodec/dca.h
> +++ b/libavcodec/dca.h
> @@ -45,7 +45,8 @@ enum DCAParseError {
>      DCA_PARSE_ERROR_SAMPLE_RATE     = -6,
>      DCA_PARSE_ERROR_RESERVED_BIT    = -7,
>      DCA_PARSE_ERROR_LFE_FLAG        = -8,
> -    DCA_PARSE_ERROR_PCM_RES         = -9
> +    DCA_PARSE_ERROR_PCM_RES         = -9,
> +    DCA_PARSE_ERROR_INVALIDDATA     = -10,
>  };
>  
>  typedef struct DCACoreFrameHeader {
> @@ -212,6 +213,8 @@ int avpriv_dca_convert_bitstream(const uint8_t *src, int src_size, uint8_t *dst,
>   * Parse and validate core frame header
>   * @return 0 on success, negative DCA_PARSE_ERROR_ code on failure
>   */
> -int avpriv_dca_parse_core_frame_header(GetBitContext *gb, DCACoreFrameHeader *h);
> +int avpriv_dca_parse_core_frame_header(DCACoreFrameHeader *h, uint8_t *buf, int size);
> +
> +int ff_dca_parse_core_frame_header(DCACoreFrameHeader *h, GetBitContext *gb);
>  
>  #endif /* AVCODEC_DCA_H */
> diff --git a/libavcodec/dca_core.c b/libavcodec/dca_core.c
> index 3add9f812b..6cb1f30a3c 100644
> --- a/libavcodec/dca_core.c
> +++ b/libavcodec/dca_core.c
> @@ -82,7 +82,7 @@ static void get_array(GetBitContext *s, int32_t *array, int size, int n)
>  static int parse_frame_header(DCACoreDecoder *s)
>  {
>      DCACoreFrameHeader h = { 0 };
> -    int err = avpriv_dca_parse_core_frame_header(&s->gb, &h);
> +    int err = ff_dca_parse_core_frame_header(&h, &s->gb);
>  
>      if (err < 0) {
>          switch (err) {
> diff --git a/libavcodec/dca_parser.c b/libavcodec/dca_parser.c
> index 7e99b16bf0..11ddb8f188 100644
> --- a/libavcodec/dca_parser.c
> +++ b/libavcodec/dca_parser.c
> @@ -263,9 +263,7 @@ static int dca_parse_params(DCAParseContext *pc1, const uint8_t *buf,
>      if ((ret = avpriv_dca_convert_bitstream(buf, DCA_CORE_FRAME_HEADER_SIZE,
>                                              hdr, DCA_CORE_FRAME_HEADER_SIZE)) < 0)
>          return ret;
> -    if ((ret = init_get_bits8(&gb, hdr, ret)) < 0)
> -        return ret;
> -    if (avpriv_dca_parse_core_frame_header(&gb, &h) < 0)
> +    if (avpriv_dca_parse_core_frame_header(&h, hdr, ret) < 0)
>          return AVERROR_INVALIDDATA;
>  
>      *duration = h.npcmblocks * DCA_PCMBLOCK_SAMPLES;
> diff --git a/libavformat/dtsdec.c b/libavformat/dtsdec.c
> index 6e0048f9bc..a3e52cd596 100644
> --- a/libavformat/dtsdec.c
> +++ b/libavformat/dtsdec.c
> @@ -101,9 +101,7 @@ static int dts_probe(AVProbeData *p)
>          if ((ret = avpriv_dca_convert_bitstream(buf - 2, DCA_CORE_FRAME_HEADER_SIZE,
>                                                  hdr,     DCA_CORE_FRAME_HEADER_SIZE)) < 0)
>              continue;
> -        if (init_get_bits8(&gb, hdr, ret) < 0)
> -            continue;
> -        if (avpriv_dca_parse_core_frame_header(&gb, &h) < 0)
> +        if (avpriv_dca_parse_core_frame_header(&h, hdr, ret) < 0)
>              continue;
>  
>          marker += 4 * h.sr_code;
> 

Will apply soon.