rate.h

/* 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 3 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, see <http://www.gnu.org/licenses/>.
 *
 */

#ifndef AUDIO_RATE_H
#define AUDIO_RATE_H

#include "common/frac.h"

namespace Audio {
class AudioStream;

typedef int16 st_sample_t;
typedef uint16 st_volume_t;
typedef uint32 st_size_t;
typedef uint32 st_rate_t;

/* Minimum and maximum values a sample can hold. */
enum {
    ST_SAMPLE_MAX = 0x7fffL,
    ST_SAMPLE_MIN = (-ST_SAMPLE_MAX - 1L)
};

static inline void clampedAdd(int16& a, int b) {
    int val;
#ifdef OUTPUT_UNSIGNED_AUDIO
    val = (a ^ 0x8000) + b;
#else
    val = a + b;
#endif

    if (val > ST_SAMPLE_MAX)
        val = ST_SAMPLE_MAX;
    else if (val < ST_SAMPLE_MIN)
        val = ST_SAMPLE_MIN;

#ifdef OUTPUT_UNSIGNED_AUDIO
    a = ((int16)val) ^ 0x8000;
#else
    a = val;
#endif
}

class RateConverter {
public:
    RateConverter() {}
    virtual ~RateConverter() {}

    virtual int convert(AudioStream &input, st_sample_t *outBuffer, st_size_t numSamples, st_volume_t vol_l, st_volume_t vol_r) = 0;

    virtual void setInputRate(st_rate_t inputRate) = 0;
    virtual void setOutputRate(st_rate_t outputRate) = 0;

    virtual st_rate_t getInputRate() const = 0;
    virtual st_rate_t getOutputRate() const = 0;

    virtual bool needsDraining() const = 0;
};

RateConverter *makeRateConverter(st_rate_t inRate, st_rate_t outRate, bool inStereo, bool outStereo, bool reverseStereo);

} // End of namespace Audio

#endif