diff options
Diffstat (limited to 'sound/decoders/raw.cpp')
-rw-r--r-- | sound/decoders/raw.cpp | 217 |
1 files changed, 124 insertions, 93 deletions
diff --git a/sound/decoders/raw.cpp b/sound/decoders/raw.cpp index 3614975d57..04f6e4255c 100644 --- a/sound/decoders/raw.cpp +++ b/sound/decoders/raw.cpp @@ -51,47 +51,19 @@ namespace Audio { */ template<bool is16Bit, bool isUnsigned, bool isLE> class RawStream : public SeekableAudioStream { - -// Allow backends to override buffer size -#ifdef CUSTOM_AUDIO_BUFFER_SIZE - static const int32 BUFFER_SIZE = CUSTOM_AUDIO_BUFFER_SIZE; -#else - static const int32 BUFFER_SIZE = 16384; -#endif - -protected: - byte *_buffer; ///< Streaming buffer - const byte *_ptr; ///< Pointer to current position in stream buffer - const int _rate; ///< Sample rate of stream - const bool _isStereo; ///< Whether this is an stereo stream - - Timestamp _playtime; ///< Calculated total play time - Common::SeekableReadStream *_stream; ///< Stream to read data from - int32 _filePos; ///< Current position in stream - int32 _diskLeft; ///< Samples left in stream in current block not yet read to buffer - int32 _bufferLeft; ///< Samples left in buffer in current block - const DisposeAfterUse::Flag _disposeAfterUse; ///< Indicates whether the stream object should be deleted when this RawStream is destructed - - const RawStreamBlockList _blocks; ///< Audio block list - RawStreamBlockList::const_iterator _curBlock; ///< Current audio block number public: RawStream(int rate, bool stereo, DisposeAfterUse::Flag disposeStream, Common::SeekableReadStream *stream, const RawStreamBlockList &blocks) - : _rate(rate), _isStereo(stereo), _playtime(0, rate), _stream(stream), _disposeAfterUse(disposeStream), _blocks(blocks), _curBlock(_blocks.begin()) { + : _rate(rate), _isStereo(stereo), _playtime(0, rate), _stream(stream), _disposeAfterUse(disposeStream), _blocks(blocks), _curBlock(_blocks.begin()), _blockLeft(0), _buffer(0) { assert(_blocks.size() > 0); - // Allocate streaming buffer - if (is16Bit) - _buffer = (byte *)malloc(BUFFER_SIZE * sizeof(int16)); - else - _buffer = (byte *)malloc(BUFFER_SIZE * sizeof(byte)); - - _ptr = _buffer; - _bufferLeft = 0; + // Setup our buffer for readBuffer + _buffer = new byte[kSampleBufferLength * (is16Bit ? 2 : 1)]; + assert(_buffer); // Set current buffer state, playing first block - _filePos = _curBlock->pos; - _diskLeft = _curBlock->len; + _stream->seek(_curBlock->pos, SEEK_SET); + _blockLeft = _curBlock->len; // Add up length of all blocks in order to caluclate total play time int32 len = 0; @@ -103,92 +75,151 @@ public: _playtime = Timestamp(0, len / (_isStereo ? 2 : 1), rate); } - - virtual ~RawStream() { + ~RawStream() { if (_disposeAfterUse == DisposeAfterUse::YES) delete _stream; - free(_buffer); + delete[] _buffer; } int readBuffer(int16 *buffer, const int numSamples); bool isStereo() const { return _isStereo; } - bool endOfData() const { return (_curBlock == _blocks.end()) && (_diskLeft == 0) && (_bufferLeft == 0); } + bool endOfData() const { return (_curBlock == _blocks.end()) && (_blockLeft == 0); } int getRate() const { return _rate; } Timestamp getLength() const { return _playtime; } bool seek(const Timestamp &where); +private: + const int _rate; ///< Sample rate of stream + const bool _isStereo; ///< Whether this is an stereo stream + Timestamp _playtime; ///< Calculated total play time + Common::SeekableReadStream *_stream; ///< Stream to read data from + const DisposeAfterUse::Flag _disposeAfterUse; ///< Indicates whether the stream object should be deleted when this RawStream is destructed + const RawStreamBlockList _blocks; ///< Audio block list + + RawStreamBlockList::const_iterator _curBlock; ///< Current audio block number + int32 _blockLeft; ///< How many bytes are still left in the current block + + /** + * Advance one block in the stream in case + * the current one is empty. + */ + void updateBlockIfNeeded(); + + byte *_buffer; ///< Buffer used in readBuffer + enum { + /** + * How many samples we can buffer at once. + * + * TODO: Check whether this size suffices + * for systems with slow disk I/O. + */ + kSampleBufferLength = 2048 + }; + + /** + * Fill the temporary sample buffer used in readBuffer. + * + * @param maxSamples Maximum samples to read. + * @return actual count of samples read. + */ + int fillBuffer(int maxSamples); }; template<bool is16Bit, bool isUnsigned, bool isLE> int RawStream<is16Bit, isUnsigned, isLE>::readBuffer(int16 *buffer, const int numSamples) { - int oldPos = _stream->pos(); - bool restoreFilePosition = false; - - int samples = numSamples; + int samplesLeft = numSamples; + + while (samplesLeft > 0) { + // Try to read up to "samplesLeft" samples. + int len = fillBuffer(samplesLeft); + + // In case we were not able to read any samples + // and we reached the end of the stream we will + // skip reading here. We do not check endOfData + // alone here to allow empty blocks in the stream. + // (TODO/FIXME: Do we really need that?) + if (!len && endOfData()) + break; - while (samples > 0 && ((_diskLeft > 0 || _bufferLeft > 0) || _curBlock != _blocks.end())) { - // Output samples in the buffer to the output - int len = MIN<int>(samples, _bufferLeft); - samples -= len; - _bufferLeft -= len; + // Adjust the samples left to read. + samplesLeft -= len; - while (len > 0) { - *buffer++ = READ_ENDIAN_SAMPLE(is16Bit, isUnsigned, _ptr, isLE); - _ptr += (is16Bit ? 2 : 1); - len--; + // Copy the data to the caller's buffer. + const byte *src = _buffer; + while (len-- > 0) { + *buffer++ = READ_ENDIAN_SAMPLE(is16Bit, isUnsigned, src, isLE); + src += (is16Bit ? 2 : 1); } + } - // Have we now finished this block? If so, read the next block - if ((_bufferLeft == 0) && (_diskLeft == 0) && _curBlock != _blocks.end()) { - // Next block - ++_curBlock; - - if (_curBlock != _blocks.end()) { - _filePos = _curBlock->pos; - _diskLeft = _curBlock->len; - } - } + return numSamples - samplesLeft; +} - // Now read more data from disk if there is more to be read - if (_bufferLeft == 0 && _diskLeft > 0) { - int32 readAmount = MIN(_diskLeft, BUFFER_SIZE); - - // TODO: We should check for both seek and read to success. - // If that is not the case, we should probably stop the - // stream playback. - _stream->seek(_filePos, SEEK_SET); - _stream->read(_buffer, readAmount * (is16Bit ? 2 : 1)); - - // Amount of data in buffer is now the amount read in, and - // the amount left to read on disk is decreased by the same amount - _bufferLeft = readAmount; - _diskLeft -= readAmount; - _ptr = (byte *)_buffer; - _filePos += readAmount * (is16Bit ? 2 : 1); - - // Set this flag now we've used the file, it restores it's - // original position. - restoreFilePosition = true; - } +template<bool is16Bit, bool isUnsigned, bool isLE> +int RawStream<is16Bit, isUnsigned, isLE>::fillBuffer(int maxSamples) { + int bufferedSamples = 0; + byte *dst = _buffer; + + // We can only read up to "kSampleBufferLength" samples + // so we take this into consideration, when trying to + // read up to maxSamples. + maxSamples = MIN<int>(kSampleBufferLength, maxSamples); + + // We will only read up to maxSamples + while (maxSamples > 0 && !endOfData()) { + // Calculate how many samples we can safely read + // from the current block. + const int len = MIN<int>(maxSamples, _blockLeft); + + // Try to read all the sample data and update the + // destination pointer. + const int bytesRead = _stream->read(dst, len * (is16Bit ? 2 : 1)); + dst += bytesRead; + + // Calculate how many samples we actually read. + const int samplesRead = bytesRead / (is16Bit ? 2 : 1); + + // Update all status variables + bufferedSamples += samplesRead; + maxSamples -= samplesRead; + _blockLeft -= samplesRead; + + // TODO: Check for possible read errors + + // Advance to the next block in case the current + // one is already finished. + updateBlockIfNeeded(); } - // In case calling code relies on the position of this stream staying - // constant, I restore the location if I've changed it. This is probably - // not necessary. - if (restoreFilePosition) - _stream->seek(oldPos, SEEK_SET); + return bufferedSamples; +} + +template<bool is16Bit, bool isUnsigned, bool isLE> +void RawStream<is16Bit, isUnsigned, isLE>::updateBlockIfNeeded() { + // Have we now finished this block? If so, read the next block + if (_blockLeft == 0 && _curBlock != _blocks.end()) { + // Next block + ++_curBlock; - return numSamples - samples; + // Check whether we reached the end of the stream + // yet. In case we did not do this, we will just + // setup the next block as new block. + if (_curBlock != _blocks.end()) { + _stream->seek(_curBlock->pos, SEEK_SET); + + // TODO: Check for errors while seeking + + _blockLeft = _curBlock->len; + } + } } template<bool is16Bit, bool isUnsigned, bool isLE> bool RawStream<is16Bit, isUnsigned, isLE>::seek(const Timestamp &where) { - _filePos = 0; - _diskLeft = 0; - _bufferLeft = 0; + _blockLeft = 0; _curBlock = _blocks.end(); if (where > _playtime) @@ -212,8 +243,8 @@ bool RawStream<is16Bit, isUnsigned, isLE>::seek(const Timestamp &where) { } else { const uint32 offset = seekSample - curSample; - _filePos = _curBlock->pos + offset * (is16Bit ? 2 : 1); - _diskLeft = _curBlock->len - offset; + _stream->seek(_curBlock->pos + offset * (is16Bit ? 2 : 1), SEEK_SET); + _blockLeft = _curBlock->len - offset; return true; } |