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audiostream.cpp

/* 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.
 *
 * $URL: https://scummvm.svn.sourceforge.net/svnroot/scummvm/scummvm/tags/release-0-11-1/sound/audiostream.cpp $
 * $Id: audiostream.cpp 30944 2008-02-23 22:50:18Z sev $
 *
 */

#include "common/endian.h"
#include "common/file.h"
#include "common/list.h"
#include "common/util.h"

#include "sound/audiostream.h"
#include "sound/mixer.h"
#include "sound/mp3.h"
#include "sound/vorbis.h"
#include "sound/flac.h"


// 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))


namespace Audio {

struct StreamFileFormat {
      /** Decodername */
      const char* decoderName;
      const char* fileExtension;
      /**
       * Pointer to a function which tries to open a file of type StreamFormat.
       * Return NULL in case of an error (invalid/nonexisting file).
       */
      AudioStream* (*openStreamFile)(Common::SeekableReadStream *stream, bool disposeAfterUse,
                              uint32 startTime, uint32 duration, uint numLoops);
};

static const StreamFileFormat STREAM_FILEFORMATS[] = {
      /* decoderName,         fileExt, openStreamFuntion */
#ifdef USE_FLAC
      { "Flac",               ".flac", makeFlacStream },
      { "Flac",               ".fla",  makeFlacStream },
#endif
#ifdef USE_VORBIS
      { "Ogg Vorbis",         ".ogg",  makeVorbisStream },
#endif
#ifdef USE_MAD
      { "MPEG Layer 3", ".mp3",  makeMP3Stream },
#endif

      { NULL, NULL, NULL } // Terminator
};

00077 AudioStream* AudioStream::openStreamFile(const Common::String &basename, uint32 startTime, uint32 duration, uint numLoops) {
      AudioStream* stream = NULL;
      Common::File *fileHandle = new Common::File();

      for (int i = 0; i < ARRAYSIZE(STREAM_FILEFORMATS)-1 && stream == NULL; ++i) {
            Common::String filename = basename + STREAM_FILEFORMATS[i].fileExtension;
            fileHandle->open(filename);
            if (fileHandle->isOpen()) {
                  // Create the stream object
                  stream = STREAM_FILEFORMATS[i].openStreamFile(fileHandle, true, startTime, duration, numLoops);
                  fileHandle = 0;
                  break;
            }
      }

      delete fileHandle;

      if (stream == NULL) {
            debug(1, "AudioStream: Could not open compressed AudioFile %s", basename.c_str());
      }

      return stream;
}

#pragma mark -
#pragma mark --- LinearMemoryStream ---
#pragma mark -


/**
 * A simple raw audio stream, purely memory based. It operates on a single
 * block of data, which is passed to it upon creation.
 * Optionally supports looping the sound.
 *
 * Design note: This code tries to be as efficient as possible (without
 * resorting to assembly, that is). To this end, it is written as a template
 * class. This way the compiler can create optimized code for each special
 * case. This results in a total of 12 versions of the code being generated.
 */
template<bool stereo, bool is16Bit, bool isUnsigned, bool isLE>
00117 class LinearMemoryStream : public AudioStream {
protected:
      const byte *_ptr;
      const byte *_end;
      const byte *_loopPtr;
      const byte *_loopEnd;
      const int _rate;
      const byte *_origPtr;

public:
      LinearMemoryStream(int rate, const byte *ptr, uint len, uint loopOffset, uint loopLen, bool autoFreeMemory)
            : _ptr(ptr), _end(ptr+len), _loopPtr(0), _loopEnd(0), _rate(rate) {

            // Verify the buffer sizes are sane
            if (is16Bit && stereo)
                  assert((len & 3) == 0 && (loopLen & 3) == 0);
            else if (is16Bit || stereo)
                  assert((len & 1) == 0 && (loopLen & 1) == 0);

            if (loopLen) {
                  _loopPtr = _ptr + loopOffset;
                  _loopEnd = _loopPtr + loopLen;
            }
            if (stereo) // Stereo requires even sized data
                  assert(len % 2 == 0);

            _origPtr = autoFreeMemory ? ptr : 0;
      }
      virtual ~LinearMemoryStream() {
            free(const_cast<byte *>(_origPtr));
      }
      int readBuffer(int16 *buffer, const int numSamples);

00150       bool isStereo() const         { return stereo; }
00151       bool endOfData() const        { return _ptr >= _end; }

00153       int getRate() const                 { return _rate; }
};

template<bool stereo, bool is16Bit, bool isUnsigned, bool isLE>
00157 int LinearMemoryStream<stereo, is16Bit, isUnsigned, isLE>::readBuffer(int16 *buffer, const int numSamples) {
      int samples = numSamples;
      while (samples > 0 && _ptr < _end) {
            int len = MIN(samples, (int)(_end - _ptr) / (is16Bit ? 2 : 1));
            samples -= len;
            do {
                  *buffer++ = READ_ENDIAN_SAMPLE(is16Bit, isUnsigned, _ptr, isLE);
                  _ptr += (is16Bit ? 2 : 1);
            } while (--len);
            // Loop, if looping was specified
            if (_loopPtr && _ptr >= _end) {
                  _ptr = _loopPtr;
                  _end = _loopEnd;
            }
      }
      return numSamples-samples;
}


#pragma mark -
#pragma mark --- Input stream factory ---
#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_LINEAR(STEREO, UNSIGNED) \
            if (is16Bit) { \
                  if (isLE) \
                        return new LinearMemoryStream<STEREO, true, UNSIGNED, true>(rate, ptr, len, loopOffset, loopLen, autoFree); \
                  else  \
                        return new LinearMemoryStream<STEREO, true, UNSIGNED, false>(rate, ptr, len, loopOffset, loopLen, autoFree); \
            } else \
                  return new LinearMemoryStream<STEREO, false, UNSIGNED, false>(rate, ptr, len, loopOffset, loopLen, autoFree)

AudioStream *makeLinearInputStream(const byte *ptr, uint32 len, int rate, byte flags, uint loopStart, uint loopEnd) {
      const bool isStereo   = (flags & Audio::Mixer::FLAG_STEREO) != 0;
      const bool is16Bit    = (flags & Audio::Mixer::FLAG_16BITS) != 0;
      const bool isUnsigned = (flags & Audio::Mixer::FLAG_UNSIGNED) != 0;
      const bool isLE       = (flags & Audio::Mixer::FLAG_LITTLE_ENDIAN) != 0;
      const bool autoFree   = (flags & Audio::Mixer::FLAG_AUTOFREE) != 0;

      uint loopOffset = 0, loopLen = 0;
      if (flags & Audio::Mixer::FLAG_LOOP) {
            if (loopEnd == 0)
                  loopEnd = len;
            assert(loopStart <= loopEnd);
            assert(loopEnd <= len);

            loopOffset = loopStart;
            loopLen = loopEnd - loopStart;
      }

      if (isStereo) {
            if (isUnsigned) {
                  MAKE_LINEAR(true, true);
            } else {
                  MAKE_LINEAR(true, false);
            }
      } else {
            if (isUnsigned) {
                  MAKE_LINEAR(false, true);
            } else {
                  MAKE_LINEAR(false, false);
            }
      }
}


#pragma mark -
#pragma mark --- Appendable audio stream ---
#pragma mark -

struct Buffer {
      byte *start;
      byte *end;
};

/**
 * Wrapped memory stream.
 */
template<bool stereo, bool is16Bit, bool isUnsigned, bool isLE>
00245 class AppendableMemoryStream : public AppendableAudioStream {
protected:

      // A mutex to avoid access problems (causing e.g. corruption of
      // the linked list) in thread aware environments.
      Common::Mutex _mutex;

      // List of all queued buffers
      Common::List<Buffer> _bufferQueue;

      // Position in the front buffer, if any
      bool _finalized;
      const int _rate;
      byte *_pos;

      inline bool eosIntern() const { return _bufferQueue.empty(); };
public:
      AppendableMemoryStream(int rate);
      ~AppendableMemoryStream();
      int readBuffer(int16 *buffer, const int numSamples);

00266       bool isStereo() const         { return stereo; }
00267       bool endOfStream() const      { return _finalized && eosIntern(); }
00268       bool endOfData() const        { return eosIntern(); }

00270       int getRate() const                 { return _rate; }

      void queueBuffer(byte *data, uint32 size);
00273       void finish()                       { _finalized = true; }
};

template<bool stereo, bool is16Bit, bool isUnsigned, bool isLE>
AppendableMemoryStream<stereo, is16Bit, isUnsigned, isLE>::AppendableMemoryStream(int rate)
 : _finalized(false), _rate(rate), _pos(0) {

}

template<bool stereo, bool is16Bit, bool isUnsigned, bool isLE>
AppendableMemoryStream<stereo, is16Bit, isUnsigned, isLE>::~AppendableMemoryStream() {
      // Clear the queue
      Common::List<Buffer>::iterator iter;
      for (iter = _bufferQueue.begin(); iter != _bufferQueue.end(); ++iter)
            delete[] iter->start;
}

template<bool stereo, bool is16Bit, bool isUnsigned, bool isLE>
00291 int AppendableMemoryStream<stereo, is16Bit, isUnsigned, isLE>::readBuffer(int16 *buffer, const int numSamples) {
      Common::StackLock lock(_mutex);

      int samples = numSamples;
      while (samples > 0 && !eosIntern()) {
            Buffer buf = *_bufferQueue.begin();
            if (_pos == 0)
                  _pos = buf.start;

            assert(buf.start <= _pos && _pos <= buf.end);
            const int samplesLeftInCurBuffer = buf.end - _pos;
            if (samplesLeftInCurBuffer == 0) {
                  delete [] buf.start;
                  _bufferQueue.erase(_bufferQueue.begin());
                  _pos = 0;
                  continue;
            }

            int len = MIN(samples, samplesLeftInCurBuffer / (is16Bit ? 2 : 1));
            samples -= len;
            do {
                  *buffer++ = READ_ENDIAN_SAMPLE(is16Bit, isUnsigned, _pos, isLE);
                  _pos += (is16Bit ? 2 : 1);
            } while (--len);
      }

      return numSamples-samples;
}

template<bool stereo, bool is16Bit, bool isUnsigned, bool isLE>
00321 void AppendableMemoryStream<stereo, is16Bit, isUnsigned, isLE>::queueBuffer(byte *data, uint32 size) {
      Common::StackLock lock(_mutex);

      // Verify the buffer size is sane
      if (is16Bit && stereo)
            assert((size & 3) == 0);
      else if (is16Bit || stereo)
            assert((size & 1) == 0);

      // Verify that the stream has not yet been finalized (by a call to finish())
      assert(!_finalized);

      // Queue the buffer
      Buffer buf = {data, data+size};
      _bufferQueue.push_back(buf);


#if 0
      // Output some stats
      uint totalSize = 0;
      Common::List<Buffer>::iterator iter;
      for (iter = _bufferQueue.begin(); iter != _bufferQueue.end(); ++iter)
            totalSize += iter->end - iter->start;
      printf("AppendableMemoryStream::queueBuffer: added a %d byte buf, a total of %d bytes are queued\n",
                        size, totalSize);
#endif
}


#define MAKE_WRAPPED(STEREO, UNSIGNED) \
            if (is16Bit) { \
                  if (isLE) \
                        return new AppendableMemoryStream<STEREO, true, UNSIGNED, true>(rate); \
                  else  \
                        return new AppendableMemoryStream<STEREO, true, UNSIGNED, false>(rate); \
            } else \
                  return new AppendableMemoryStream<STEREO, false, UNSIGNED, false>(rate)

AppendableAudioStream *makeAppendableAudioStream(int rate, byte _flags) {
      const bool isStereo = (_flags & Audio::Mixer::FLAG_STEREO) != 0;
      const bool is16Bit = (_flags & Audio::Mixer::FLAG_16BITS) != 0;
      const bool isUnsigned = (_flags & Audio::Mixer::FLAG_UNSIGNED) != 0;
      const bool isLE       = (_flags & Audio::Mixer::FLAG_LITTLE_ENDIAN) != 0;

      if (isStereo) {
            if (isUnsigned) {
                  MAKE_WRAPPED(true, true);
            } else {
                  MAKE_WRAPPED(true, false);
            }
      } else {
            if (isUnsigned) {
                  MAKE_WRAPPED(false, true);
            } else {
                  MAKE_WRAPPED(false, false);
            }
      }
}


} // End of namespace Audio

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