SoundData.h

// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at

//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
// Copyright 2020 Phil Schatzmann

#pragma once

#include <stdint.h>
#include <stdbool.h>
#include <algorithm>    // std::min

/**
 * @brief Utility structure that can be used to split a int32_t up into 2 separate channels with int16_t data.
 * @author Phil Schatzmann
 * @copyright Apache License Version 2
 */
struct __attribute__((packed)) Frame {
  int16_t channel1;
  int16_t channel2;

  Frame(int v=0){
    channel1 = channel2 = v;
  }
  
  Frame(int ch1, int ch2){
    channel1 = ch1;
    channel2 = ch2;
  }

};

// support for legacy name;
using Channels = Frame;

/**
 * @brief Channel Information
 * @author Phil Schatzmann
 * @copyright Apache License Version 2
 */
enum ChannelInfo {
    Both,
    Left,
    Right
};

/**
 * @brief Sound data as byte stream. We support TwoChannelSoundData (uint16_t + uint16_t) and 
 * OneChannelSoundData which stores the data as array of uint16_t 
 * We provide the complete sound data as a simple c array which 
 * can be prepared e.g. in the following way
 *
 * - Open any sound file in Audacity. Make sure that it contains 2 channels
 *   - Select Tracks -> Resample and select 44100
 *   - Export -> Export Audio -> Header Raw ; Signed 16 bit PCM
 * - Convert to c file e.g. with "xxd -i file_example_WAV_1MG.raw file_example_WAV_1MG.c"
 *   - add the const qualifier to the array definition. E.g const unsigned char file_example_WAV_1MG_raw[] = {
 * @ingroup a2dp
 * @author Phil Schatzmann
 * @copyright Apache License Version 2
 */

class SoundData {
  public:
     virtual int32_t get2ChannelData(int32_t pos, int32_t len, uint8_t *data);
     virtual int32_t getData(int32_t pos, Frame &channels);
     virtual void setDataRaw( uint8_t* data, int32_t len);
     /**
      * Automatic restart playing on end
      */
     bool doLoop();
     void setLoop(bool loop);

  private:
     bool automatic_loop;
};


/**
 * @brief Data is provided in two channels of int16 data: so 
 * len is in 4 byte entries (int16 + int16)
 * @author Phil Schatzmann
 * @copyright Apache License Version 2
 */
class TwoChannelSoundData : public SoundData {
public:
    TwoChannelSoundData(bool loop=false);
    TwoChannelSoundData(Frame *data, int32_t len, bool loop=false);
    void setData( Frame *data, int32_t len);
    void setDataRaw( uint8_t* data, int32_t len);
    int32_t getData(int32_t pos, int32_t len, Frame *data);
    int32_t getData(int32_t pos, Frame &channels);
    int32_t get2ChannelData(int32_t pos, int32_t len, uint8_t *data);
    // the number of frames
    int32_t count(){
      return len;
    }
private:
    Frame* data;
    int32_t len; // length of all data in base unit of subclass
};


/**
 * @brief 1 Channel data is provided as int16 values
 * @author Phil Schatzmann
 * @copyright Apache License Version 2
 */
class OneChannelSoundData : public SoundData {
  public:
    OneChannelSoundData(bool loop=false, ChannelInfo channelInfo=Both);
    OneChannelSoundData(int16_t *data, int32_t len, bool loop=false, ChannelInfo channelInfo=Both);
    void setData( int16_t *data, int32_t len);
    void setDataRaw( uint8_t* data, int32_t len);
    int32_t getData(int32_t pos, int32_t len, int16_t *data);
    int32_t getData(int32_t pos, Frame &frame);
    int32_t get2ChannelData(int32_t pos, int32_t len, uint8_t *data);
  private:
    int16_t* data;
    int32_t len;
    ChannelInfo channelInfo;
};


/**
 * @brief 1 Channel data is provided as signed int8 values.
 * @author Phil Schatzmann
 * @copyright Apache License Version 2
 */
class OneChannel8BitSoundData : public SoundData {
  public:
    OneChannel8BitSoundData(bool loop=false, ChannelInfo channelInfo=Both);
    OneChannel8BitSoundData(int8_t *data, int32_t len, bool loop=false, ChannelInfo channelInfo=Both);
    void setData( int8_t *data, int32_t len);
    void setDataRaw( uint8_t* data, int32_t len);
    int32_t getData(int32_t pos, int32_t len, int8_t *data);
    int32_t getData(int32_t pos, Frame &frame);
    int32_t get2ChannelData(int32_t pos, int32_t len, uint8_t *data);
  private:
    int8_t* data;
    int32_t len;
    ChannelInfo channelInfo;
};