Recorder: save base WAV header in const variable

/*

 * Copyright (C) 2017 The LineageOS Project

 * Copyright (C) 2017-2022 The LineageOS Project

 *

 * Licensed under the Apache License, Version 2.0 (the "License");

 * you may not use this file except in compliance with the License.

import java.io.OutputStream;

import java.nio.file.Files;

import java.nio.file.Path;

import java.util.Arrays;

public final class PcmConverter {

    private static final long SAMPLE_RATE = 44100;

    private static final int RECORDER_BPP = 16;

    private static final int CHANNELS = 1;

    private static final byte RECORDER_BPP = 16;

    private static final byte CHANNELS = 1;

    private static final long BYTE_RATE = CHANNELS * SAMPLE_RATE * RECORDER_BPP / 8;

    private static final byte[] WAV_HEADER = {

            'R', 'I', 'F', 'F',

            0, 0, 0, 0, // data length placeholder

            'W', 'A', 'V', 'E',

            'f', 'm', 't', ' ', // 'fmt ' chunk

            16, // 4 bytes: size of 'fmt ' chunk

            0, 0, 0, 1, // format = 1

            0,

            CHANNELS,

            0,

            (byte) (SAMPLE_RATE & 0xff), (byte) ((SAMPLE_RATE >> 8) & 0xff), 0, 0, // sample rate

            (byte) (BYTE_RATE & 0xff), (byte) ((BYTE_RATE >> 8) & 0xff),

            (byte) ((BYTE_RATE >> 16) & 0xff), 0, // byte rate

            (byte) (CHANNELS * RECORDER_BPP / 8),  // block align

            0,

            RECORDER_BPP, // bits per sample

            0,

            'd', 'a', 't', 'a',

            0, 0, 0, 0, // audio length placeholder

    };

    private static final String TAG = "PcmConverter";

    private PcmConverter() {

    // http://stackoverflow.com/questions/4440015/java-pcm-to-wav

    private static void writeWaveHeader(OutputStream out, long audioLength,

                                        long dataLength) throws IOException {

        byte[] header = new byte[44];

        byte[] header = Arrays.copyOf(WAV_HEADER, WAV_HEADER.length);

        header[0] = 'R';  // RIFF/WAVE header

        header[1] = 'I';

        header[2] = 'F';

        header[3] = 'F';

        header[4] = (byte) (dataLength & 0xff);

        header[5] = (byte) ((dataLength >> 8) & 0xff);

        header[6] = (byte) ((dataLength >> 16) & 0xff);

        header[7] = (byte) ((dataLength >> 24) & 0xff);

        header[8] = 'W';

        header[9] = 'A';

        header[10] = 'V';

        header[11] = 'E';

        header[12] = 'f';  // 'fmt ' chunk

        header[13] = 'm';

        header[14] = 't';

        header[15] = ' ';

        header[16] = 16;  // 4 bytes: size of 'fmt ' chunk

        header[17] = 0;

        header[18] = 0;

        header[19] = 0;

        header[20] = 1;  // format = 1

        header[21] = 0;

        header[22] = (byte) CHANNELS;

        header[23] = 0;

        header[24] = (byte) (SAMPLE_RATE & 0xff);

        header[25] = (byte) ((SAMPLE_RATE >> 8) & 0xff);

        header[26] = (byte) (0L);

        header[27] = (byte) (0L);

        header[28] = (byte) (BYTE_RATE & 0xff);

        header[29] = (byte) ((BYTE_RATE >> 8) & 0xff);

        header[30] = (byte) ((BYTE_RATE >> 16) & 0xff);

        header[31] = (byte) (0L);

        header[32] = (byte) (CHANNELS * RECORDER_BPP / 8);  // block align

        header[33] = 0;

        header[34] = RECORDER_BPP;  // bits per sample

        header[35] = 0;

        header[36] = 'd';

        header[37] = 'a';

        header[38] = 't';

        header[39] = 'a';

        header[40] = (byte) (audioLength & 0xff);

        header[41] = (byte) ((audioLength >> 8) & 0xff);

        header[42] = (byte) ((audioLength >> 16) & 0xff);

        header[43] = (byte) ((audioLength >> 24) & 0xff);

        out.write(header, 0, 44);

        out.write(header, 0, header.length);

    }

}