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/* ScummVM - Scumm Interpreter
* Copyright (C) 2001-2004 The ScummVM project
*
* 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*
* $Header$
*
*/
#ifndef AUDIOSTREAM_H
#define AUDIOSTREAM_H
#include "stdafx.h"
#include "common/scummsys.h"
#include "common/util.h"
/**
* Generic input stream for the resampling code.
*/
class AudioStream {
public:
virtual ~AudioStream() {}
/**
* Fill the given buffer with up to numSamples samples.
* Returns the actual number of samples read, or -1 if
* a critical error occured (note: you *must* check if
* this value is less than what you requested, this can
* happen when the stream is fully used up).
* For stereo stream, buffer will be filled with interleaved
* left and right channel samples.
*/
virtual int readBuffer(int16 *buffer, const int numSamples) = 0;
/**
* Read a single (16 bit signed) sample from the stream.
*/
// virtual int16 read() = 0;
/** Is this a stereo stream? */
virtual bool isStereo() const = 0;
/**
* End of data reached? If this returns true, it means that at this
* time there is no data available in the stream. However there may be
* more data in the future.
* This is used by e.g. a rate converter to decide whether to keep on
* converting data or stop.
*/
virtual bool endOfData() const = 0;
/**
* End of stream reached? If this returns true, it means that all data
* in this stream is used up and no additional data will appear in it
* in the future.
* This is used by the mixer to decide whether a given stream shall be
* removed from the list of active streams (and thus be destroyed).
* By default this maps to endOfData()
*/
virtual bool endOfStream() const { return endOfData(); }
/** Sample rate of the stream. */
virtual int getRate() const = 0;
/**
* This function returns the number of samples that were delivered to
* the mixer which is a rough estimate of how moch time of the stream
* has been played.
* The exact value is not available as it needs information from the
* audio device on how many samples have been already played
* As our buffer is relatively short the estimate is exact enough
* The return -1 is kind of a hack as this function is only required
* for the video audio sync in the bs2 cutscenes I am to lazy to
* implement it for all subclasses
*/
virtual int getSamplesPlayed() const { return -1; }
};
class AppendableAudioStream : public AudioStream {
public:
virtual void append(const byte *data, uint32 len) = 0;
virtual void finish() = 0;
};
class ZeroInputStream : public AudioStream {
private:
int _len;
public:
ZeroInputStream(uint len) : _len(len) { }
int readBuffer(int16 *buffer, const int numSamples) {
int samples = MIN(_len, numSamples);
memset(buffer, 0, samples * 2);
_len -= samples;
return samples;
}
int16 read() { assert(_len > 0); _len--; return 0; }
bool isStereo() const { return false; }
bool eos() const { return _len <= 0; }
int getRate() const { return -1; }
};
AudioStream *makeLinearInputStream(int rate, byte _flags, const byte *ptr, uint32 len, uint loopOffset, uint loopLen);
AppendableAudioStream *makeAppendableAudioStream(int rate, byte _flags, uint32 len);
#endif
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