A code snippet to create and write audio data to .WAV audio file format

WAVExporter.cpp

#include <iostream>
#include <cstdint>
/*******************************************************************************
    WAVE File chunks overview
    ____________________________
    | RIFF WAVE Chunk	       |
    |   groupID  = 'RIFF'      |
    |   riffType = 'WAVE'      |
    |    __________________    |
    |   | Format Chunk     |   |
    |   |   ckID = 'fmt '  |   |
    |   |__________________|   |
    |    __________________    |
    |   | Sound Data Chunk |   |
    |   |   ckID = 'data'  |   |
    |   |__________________|   |
    |__________________________|
*******************************************************************************/
/*
 * Note:- Do not change the order of the variables as it represents the canonical format
 * any changes or re-ordering of the variables order can result in corrupted .wav files
 */
struct SimpleWaveFileFormat
{
    // RIFF Wave Chunk
    unsigned char   m_RIFFChunkID[4];
    std::uint32_t   m_RIFFChunkSize;
    unsigned char   m_Format[4];

    // Format Chunk
    unsigned char   m_FormatChunkID[4];
    std::uint32_t   m_FormatChunkSize;
    std::uint16_t   m_AudioFormat;
    std::uint16_t   m_NumChannels;
    std::uint32_t   m_SampleRate;
    std::uint32_t   m_ByteRate;
    std::uint16_t   m_BlockAlign;
    std::uint16_t   m_BitsPerSample;

    // Sound Data Chunk
    unsigned char   m_SoundChunkID[4];
    std::uint32_t   m_SoundChunkSize;
};

bool ExportWAVEFile(const char* fileName, void* soundData, std::int32_t sampleRate, std::int32_t bitsPerSample, std::int16_t numChannels, std::int32_t dataSize)
{
    // Try opening the file
    FILE *audioFile = fopen(fileName, "w+b"); // w+ => write as well as update after opening the file, b indicates open file as binary file
    if (!audioFile)
    {
        std::cerr << "Error opening the file" << std::endl;
        return false;
    }

    SimpleWaveFileFormat wavFileFormat;

    // Fill RIFF Wave chunk data
    memcpy(wavFileFormat.m_RIFFChunkID, "RIFF", 4);     /* Group ID string */
    wavFileFormat.m_RIFFChunkSize = dataSize + 4;       /* +4 because we added a 4 byte string */
    memcpy(wavFileFormat.m_Format, "WAVE", 4);

    // Fill the Format Chunk
    memcpy(wavFileFormat.m_FormatChunkID, "fmt ", 4);
    wavFileFormat.m_FormatChunkSize = 16;
    wavFileFormat.m_AudioFormat = 1;
    wavFileFormat.m_NumChannels = numChannels;
    wavFileFormat.m_SampleRate = sampleRate;
    wavFileFormat.m_ByteRate = sampleRate * numChannels * bitsPerSample / 8;
    wavFileFormat.m_BlockAlign = numChannels * bitsPerSample / 8;
    wavFileFormat.m_BitsPerSample = bitsPerSample;

    // Fill Sound Data Chunk
    memcpy(wavFileFormat.m_SoundChunkID, "data", 4);
    wavFileFormat.m_SoundChunkSize = dataSize;

    // Write the file format to the file
    fwrite(&wavFileFormat, sizeof(SimpleWaveFileFormat), 1, audioFile);

    // Write the data to the file with the simple wav format style
    fwrite(soundData, dataSize, 1, audioFile);

    // Close the file and indicate success
    fclose(audioFile);
    return true;
}

uint8_t* LoadWAVEFile(const char* filePath, SimpleWaveFileFormat& fileFormat)
{
    std::cout << "Here";
    FILE* fp = fopen(filePath,"rb");
    if (!fp) {
        printf("%s can't open audio file\n",filePath);
        exit(1);
    }

    // Read the data format information from the header file
    fread(&fileFormat, sizeof(SimpleWaveFileFormat), 1, fp);
    // Find how many bytes to read
    uint32_t bytesToRead=0;
    bytesToRead = fileFormat.m_SoundChunkSize - sizeof(SimpleWaveFileFormat);
    uint8_t* buf;
    for (; bytesToRead > 0; bytesToRead--)
    {
        fread(&buf, 1, 1, fp);
    }
    return buf;
}