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