[vlc-devel] [PATCH 3/9] demux: mkv: simplify block handling

[Steve Lhomme]

Although I said everything in libmatroska can be used, this class is not 
really supposed to be used, hence the name Internal.

But in reality it should be but with a different name. So we can use it 
and will change the name when/if it does.


On 2018-07-16 5:19, Filip Roséen wrote:
> As KaxSimpleBlock and KaxBlock inherit from the same base we can get
> rid of all these nasty if-else's by creating an object that refers to
> the one we are interested in.
> ---
>   modules/demux/mkv/matroska_segment_seeker.cpp | 17 ++++----
>   modules/demux/mkv/mkv.cpp                     | 39 +++++++------------
>   2 files changed, 21 insertions(+), 35 deletions(-)
>
> diff --git a/modules/demux/mkv/matroska_segment_seeker.cpp b/modules/demux/mkv/matroska_segment_seeker.cpp
> index a4c5daec29..2c17b60328 100644
> --- a/modules/demux/mkv/matroska_segment_seeker.cpp
> +++ b/modules/demux/mkv/matroska_segment_seeker.cpp
> @@ -359,16 +359,13 @@ SegmentSeeker::index_unsearched_range( matroska_segment_c& ms, Range search_area
>           if( ms.BlockGet( block, simpleblock, &b_key_picture, &b_discardable_picture, &i_block_duration ) )
>               break;
>   
> -        if( simpleblock ) {
> -            block_pos = simpleblock->GetElementPosition();
> -            block_pts = simpleblock->GlobalTimecode() / 1000;
> -            track_id  = simpleblock->TrackNum();
> -        }
> -        else {
> -            block_pos = block->GetElementPosition();
> -            block_pts = block->GlobalTimecode() / 1000;
> -            track_id  = block->TrackNum();
> -        }
> +        KaxInternalBlock& internal_block = simpleblock
> +            ? static_cast<KaxInternalBlock&>( *simpleblock )
> +            : static_cast<KaxInternalBlock&>( *block );
> +
> +        block_pos = internal_block.GetElementPosition();
> +        block_pts = internal_block.GlobalTimecode() / 1000;
> +        track_id  = internal_block.TrackNum();
>   
>           bool const b_valid_track = ms.FindTrackByBlock( block, simpleblock ) != NULL;
>   
> diff --git a/modules/demux/mkv/mkv.cpp b/modules/demux/mkv/mkv.cpp
> index 407bc50013..220a061e57 100644
> --- a/modules/demux/mkv/mkv.cpp
> +++ b/modules/demux/mkv/mkv.cpp
> @@ -517,6 +517,10 @@ void BlockDecode( demux_t *p_demux, KaxBlock *block, KaxSimpleBlock *simpleblock
>       demux_sys_t *p_sys = (demux_sys_t *)p_demux->p_sys;
>       matroska_segment_c *p_segment = p_sys->p_current_vsegment->CurrentSegment();
>   
> +    KaxInternalBlock& internal_block = simpleblock
> +        ? static_cast<KaxInternalBlock&>( *simpleblock )
> +        : static_cast<KaxInternalBlock&>( *block );
> +
>       if( !p_segment ) return;
>   
>       mkv_track_t *p_track = p_segment->FindTrackByBlock( block, simpleblock );
> @@ -550,28 +554,14 @@ void BlockDecode( demux_t *p_demux, KaxBlock *block, KaxSimpleBlock *simpleblock
>       }
>   
>       size_t frame_size = 0;
> -    size_t block_size = 0;
> -
> -    if( simpleblock != NULL )
> -        block_size = simpleblock->GetSize();
> -    else
> -        block_size = block->GetSize();
> -
> -    const unsigned int i_number_frames = block != NULL ? block->NumberFrames() :
> -            ( simpleblock != NULL ? simpleblock->NumberFrames() : 0 );
> +    size_t block_size = internal_block.GetSize();
> +    const unsigned i_number_frames = internal_block.NumberFrames();
>   
>       for( unsigned int i_frame = 0; i_frame < i_number_frames; i_frame++ )
>       {
>           block_t *p_block;
> -        DataBuffer *data;
> -        if( simpleblock != NULL )
> -        {
> -            data = &simpleblock->GetBuffer(i_frame);
> -        }
> -        else
> -        {
> -            data = &block->GetBuffer(i_frame);
> -        }
> +        DataBuffer *data = &internal_block.GetBuffer(i_frame);
> +
>           frame_size += data->Size();
>           if( !data->Buffer() || data->Size() > frame_size || frame_size > block_size  )
>           {
> @@ -746,6 +736,10 @@ static int Demux( demux_t *p_demux)
>           return VLC_DEMUXER_EOF;
>       }
>   
> +    KaxInternalBlock& internal_block = block
> +        ? static_cast<KaxInternalBlock&>( *block )
> +        : static_cast<KaxInternalBlock&>( *simpleblock );
> +
>       {
>           mkv_track_t *p_track = p_segment->FindTrackByBlock( block, simpleblock );
>   
> @@ -761,10 +755,7 @@ static int Demux( demux_t *p_demux)
>   
>           if( track.i_skip_until_fpos != std::numeric_limits<uint64_t>::max() ) {
>   
> -            uint64_t block_fpos = 0;
> -
> -            if( block ) block_fpos = block->GetElementPosition();
> -            else        block_fpos = simpleblock->GetElementPosition();
> +            uint64_t block_fpos = internal_block.GetElementPosition();
>   
>               if ( track.i_skip_until_fpos > block_fpos )
>               {
> @@ -811,9 +802,7 @@ static int Demux( demux_t *p_demux)
>       /* set pts */
>       {
>           p_sys->i_pts = p_sys->i_mk_chapter_time + VLC_TICK_0;
> -
> -        if( simpleblock != NULL ) p_sys->i_pts += simpleblock->GlobalTimecode() / INT64_C( 1000 );
> -        else                      p_sys->i_pts +=       block->GlobalTimecode() / INT64_C( 1000 );
> +        p_sys->i_pts += internal_block.GlobalTimecode() / INT64_C( 1000 );
>       }
>   
>       if ( p_vsegment->CurrentEdition() &&
> -- 
> 2.18.0
>
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