Method pullBuffer

distrho/src/jackbridge/rtaudio/RtAudio.cpp:3922–3981

attempt to pull a buffer from the ring buffer from the current "out" index

  // attempt to pull a buffer from the ring buffer from the current "out" index
  bool pullBuffer( char* buffer, unsigned int bufferSize, RtAudioFormat format )
  {
    if ( !buffer ||                 // incoming buffer is NULL
         bufferSize == 0 ||         // incoming buffer has no data
         bufferSize > bufferSize_ ) // incoming buffer too large
    {
      return false;
    }

    unsigned int relInIndex = inIndex_;
    unsigned int outIndexEnd = outIndex_ + bufferSize;
    if ( relInIndex < outIndex_ && outIndexEnd >= bufferSize_ ) {
      relInIndex += bufferSize_;
    }

    // the "OUT" index CANNOT BEGIN at the "IN" index
    // the "OUT" index CAN END at the "IN" index
    if ( outIndex_ <= relInIndex && outIndexEnd > relInIndex ) {
      return false; // not enough space between "out" index and "in" index
    }

    // copy buffer from internal to external
    int fromZeroSize = outIndex_ + bufferSize - bufferSize_;
    fromZeroSize = fromZeroSize < 0 ? 0 : fromZeroSize;
    int fromOutSize = bufferSize - fromZeroSize;

    switch( format )
    {
      case RTAUDIO_SINT8:
        memcpy( buffer, &( ( char* ) buffer_ )[outIndex_], fromOutSize * sizeof( char ) );
        memcpy( &( ( char* ) buffer )[fromOutSize], buffer_, fromZeroSize * sizeof( char ) );
        break;
      case RTAUDIO_SINT16:
        memcpy( buffer, &( ( short* ) buffer_ )[outIndex_], fromOutSize * sizeof( short ) );
        memcpy( &( ( short* ) buffer )[fromOutSize], buffer_, fromZeroSize * sizeof( short ) );
        break;
      case RTAUDIO_SINT24:
        memcpy( buffer, &( ( S24* ) buffer_ )[outIndex_], fromOutSize * sizeof( S24 ) );
        memcpy( &( ( S24* ) buffer )[fromOutSize], buffer_, fromZeroSize * sizeof( S24 ) );
        break;
      case RTAUDIO_SINT32:
        memcpy( buffer, &( ( int* ) buffer_ )[outIndex_], fromOutSize * sizeof( int ) );
        memcpy( &( ( int* ) buffer )[fromOutSize], buffer_, fromZeroSize * sizeof( int ) );
        break;
      case RTAUDIO_FLOAT32:
        memcpy( buffer, &( ( float* ) buffer_ )[outIndex_], fromOutSize * sizeof( float ) );
        memcpy( &( ( float* ) buffer )[fromOutSize], buffer_, fromZeroSize * sizeof( float ) );
        break;
      case RTAUDIO_FLOAT64:
        memcpy( buffer, &( ( double* ) buffer_ )[outIndex_], fromOutSize * sizeof( double ) );
        memcpy( &( ( double* ) buffer )[fromOutSize], buffer_, fromZeroSize * sizeof( double ) );
        break;
    }

    // update "out" index
    outIndex_ += bufferSize;
    outIndex_ %= bufferSize_;