mirror of
https://github.com/libretro/scummvm.git
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225 lines
7.6 KiB
C++
225 lines
7.6 KiB
C++
/* ScummVM - Graphic Adventure Engine
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*
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* ScummVM is the legal property of its developers, whose names
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* are too numerous to list here. Please refer to the COPYRIGHT
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* file distributed with this source distribution.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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*
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*/
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#include "common/endian.h"
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#include "common/memstream.h"
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#include "common/textconsole.h"
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#include "common/util.h"
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#include "audio/audiostream.h"
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#include "audio/decoders/raw.h"
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namespace Audio {
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// This used to be an inline template function, but
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// buggy template function handling in MSVC6 forced
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// us to go with the macro approach. So far this is
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// the only template function that MSVC6 seemed to
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// compile incorrectly. Knock on wood.
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#define READ_ENDIAN_SAMPLE(is16Bit, isUnsigned, ptr, isLE) \
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((is16Bit ? (isLE ? READ_LE_UINT16(ptr) : READ_BE_UINT16(ptr)) : (*ptr << 8)) ^ (isUnsigned ? 0x8000 : 0))
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#pragma mark -
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#pragma mark --- RawStream ---
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#pragma mark -
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/**
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* This is a stream, which allows for playing raw PCM data from a stream.
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*/
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template<bool is16Bit, bool isUnsigned, bool isLE>
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class RawStream : public SeekableAudioStream {
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public:
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RawStream(int rate, bool stereo, DisposeAfterUse::Flag disposeStream, Common::SeekableReadStream *stream)
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: _rate(rate), _isStereo(stereo), _playtime(0, rate), _stream(stream, disposeStream), _endOfData(false), _buffer(0) {
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// Setup our buffer for readBuffer
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_buffer = new byte[kSampleBufferLength * (is16Bit ? 2 : 1)];
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assert(_buffer);
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// Calculate the total playtime of the stream
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_playtime = Timestamp(0, _stream->size() / (_isStereo ? 2 : 1) / (is16Bit ? 2 : 1), rate);
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}
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~RawStream() {
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delete[] _buffer;
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}
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int readBuffer(int16 *buffer, const int numSamples);
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bool isStereo() const { return _isStereo; }
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bool endOfData() const { return _endOfData; }
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int getRate() const { return _rate; }
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Timestamp getLength() const { return _playtime; }
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bool seek(const Timestamp &where);
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private:
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const int _rate; ///< Sample rate of stream
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const bool _isStereo; ///< Whether this is an stereo stream
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Timestamp _playtime; ///< Calculated total play time
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Common::DisposablePtr<Common::SeekableReadStream> _stream; ///< Stream to read data from
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bool _endOfData; ///< Whether the stream end has been reached
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byte *_buffer; ///< Buffer used in readBuffer
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enum {
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/**
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* How many samples we can buffer at once.
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*
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* TODO: Check whether this size suffices
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* for systems with slow disk I/O.
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*/
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kSampleBufferLength = 2048
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};
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/**
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* Fill the temporary sample buffer used in readBuffer.
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*
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* @param maxSamples Maximum samples to read.
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* @return actual count of samples read.
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*/
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int fillBuffer(int maxSamples);
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};
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template<bool is16Bit, bool isUnsigned, bool isLE>
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int RawStream<is16Bit, isUnsigned, isLE>::readBuffer(int16 *buffer, const int numSamples) {
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int samplesLeft = numSamples;
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while (samplesLeft > 0) {
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// Try to read up to "samplesLeft" samples.
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int len = fillBuffer(samplesLeft);
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// In case we were not able to read any samples
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// we will stop reading here.
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if (!len)
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break;
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// Adjust the samples left to read.
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samplesLeft -= len;
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// Copy the data to the caller's buffer.
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const byte *src = _buffer;
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while (len-- > 0) {
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*buffer++ = READ_ENDIAN_SAMPLE(is16Bit, isUnsigned, src, isLE);
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src += (is16Bit ? 2 : 1);
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}
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}
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return numSamples - samplesLeft;
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}
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template<bool is16Bit, bool isUnsigned, bool isLE>
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int RawStream<is16Bit, isUnsigned, isLE>::fillBuffer(int maxSamples) {
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int bufferedSamples = 0;
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byte *dst = _buffer;
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// We can only read up to "kSampleBufferLength" samples
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// so we take this into consideration, when trying to
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// read up to maxSamples.
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maxSamples = MIN<int>(kSampleBufferLength, maxSamples);
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// We will only read up to maxSamples
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while (maxSamples > 0 && !endOfData()) {
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// Try to read all the sample data and update the
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// destination pointer.
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const int bytesRead = _stream->read(dst, maxSamples * (is16Bit ? 2 : 1));
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dst += bytesRead;
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// Calculate how many samples we actually read.
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const int samplesRead = bytesRead / (is16Bit ? 2 : 1);
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// Update all status variables
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bufferedSamples += samplesRead;
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maxSamples -= samplesRead;
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// We stop stream playback, when we reached the end of the data stream.
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// We also stop playback when an error occures.
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if (_stream->pos() == _stream->size() || _stream->err() || _stream->eos())
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_endOfData = true;
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}
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return bufferedSamples;
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}
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template<bool is16Bit, bool isUnsigned, bool isLE>
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bool RawStream<is16Bit, isUnsigned, isLE>::seek(const Timestamp &where) {
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_endOfData = true;
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if (where > _playtime)
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return false;
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const uint32 seekSample = convertTimeToStreamPos(where, getRate(), isStereo()).totalNumberOfFrames();
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_stream->seek(seekSample * (is16Bit ? 2 : 1), SEEK_SET);
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// In case of an error we will not continue stream playback.
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if (!_stream->err() && !_stream->eos() && _stream->pos() != _stream->size())
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_endOfData = false;
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return true;
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}
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#pragma mark -
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#pragma mark --- Raw stream factories ---
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#pragma mark -
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/* In the following, we use preprocessor / macro tricks to simplify the code
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* which instantiates the input streams. We used to use template functions for
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* this, but MSVC6 / EVC 3-4 (used for WinCE builds) are extremely buggy when it
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* comes to this feature of C++... so as a compromise we use macros to cut down
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* on the (source) code duplication a bit.
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* So while normally macro tricks are said to make maintenance harder, in this
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* particular case it should actually help it :-)
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*/
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#define MAKE_RAW_STREAM(UNSIGNED) \
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if (is16Bit) { \
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if (isLE) \
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return new RawStream<true, UNSIGNED, true>(rate, isStereo, disposeAfterUse, stream); \
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else \
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return new RawStream<true, UNSIGNED, false>(rate, isStereo, disposeAfterUse, stream); \
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} else \
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return new RawStream<false, UNSIGNED, false>(rate, isStereo, disposeAfterUse, stream)
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SeekableAudioStream *makeRawStream(Common::SeekableReadStream *stream,
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int rate, byte flags,
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DisposeAfterUse::Flag disposeAfterUse) {
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const bool isStereo = (flags & Audio::FLAG_STEREO) != 0;
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const bool is16Bit = (flags & Audio::FLAG_16BITS) != 0;
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const bool isUnsigned = (flags & Audio::FLAG_UNSIGNED) != 0;
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const bool isLE = (flags & Audio::FLAG_LITTLE_ENDIAN) != 0;
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assert(stream->size() % ((is16Bit ? 2 : 1) * (isStereo ? 2 : 1)) == 0);
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if (isUnsigned) {
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MAKE_RAW_STREAM(true);
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} else {
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MAKE_RAW_STREAM(false);
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}
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}
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SeekableAudioStream *makeRawStream(const byte *buffer, uint32 size,
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int rate, byte flags,
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DisposeAfterUse::Flag disposeAfterUse) {
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return makeRawStream(new Common::MemoryReadStream(buffer, size, disposeAfterUse), rate, flags, DisposeAfterUse::YES);
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}
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} // End of namespace Audio
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