OpenRCT2/src/openrct2/audio/MemoryAudioSource.cpp

#pragma region Copyright (c) 2014-2016 OpenRCT2 Developers
/*****************************************************************************
 * OpenRCT2, an open source clone of Roller Coaster Tycoon 2.
 *
 * OpenRCT2 is the work of many authors, a full list can be found in contributors.md
 * For more information, visit https://github.com/OpenRCT2/OpenRCT2
 *
 * OpenRCT2 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.
 *
 * A full copy of the GNU General Public License can be found in licence.txt
 *****************************************************************************/
#pragma endregion

#include "../core/Math.hpp"
#include "../core/Memory.hpp"
#include "AudioMixer.h"
#include "AudioSource.h"

#pragma pack(push, 1)
    struct WaveFormatEx
    {
        uint16 encoding;
        uint16 channels;
        uint32 frequency;
        uint32 byterate;
        uint16 blockalign;
        uint16 bitspersample;
        uint16 extrasize;
    };
    assert_struct_size(WaveFormatEx, 18);
#pragma pack(pop)

/**
 * An audio source where raw PCM data is initially loaded into RAM from
 * a file and then streamed.
 */
class MemoryAudioSource : public IAudioSource
{
private:
    AudioFormat _format = { 0 };
    uint8 *     _data = nullptr;
    size_t      _length = 0;
    bool        _isSDLWav = false;

public:
    ~MemoryAudioSource()
    {
        Unload();
    }

    uint64 GetLength() override
    {
        return _length;
    }

    AudioFormat GetFormat() override
    {
        return _format;
    }

    size_t Read(void * dst, uint64 offset, size_t len) override
    {
        size_t bytesToRead = 0;
        if (offset < _length)
        {
            bytesToRead = (size_t)Math::Min<uint64>(len, _length - offset);
            Memory::Copy<void>(dst, _data + offset, bytesToRead);
        }
        return bytesToRead;
    }

    bool LoadWAV(const utf8 * path)
    {
        log_verbose("MemoryAudioSource::LoadWAV(%s)", path);

        Unload();

        bool result = false;
        SDL_RWops * rw = SDL_RWFromFile(path, "rb");
        if (rw != nullptr)
        {
            SDL_AudioSpec audiospec = { 0 };
            uint32 audioLen;
            SDL_AudioSpec * spec = SDL_LoadWAV_RW(rw, false, &audiospec, &_data, &audioLen);
            if (spec != nullptr)
            {
                _format.freq = spec->freq;
                _format.format = spec->format;
                _format.channels = spec->channels;
                _length = audioLen;
                _isSDLWav = true;
                result = true;
            }
            else
            {
                log_verbose("Error loading %s, unsupported WAV format", path);
            }
            SDL_RWclose(rw);
        }
        else
        {
            log_verbose("Error loading %s", path);
        }
        return result;
    }

    bool LoadCSS1(const utf8 * path, size_t index)
    {
        log_verbose("MemoryAudioSource::LoadCSS1(%s, %d)", path, index);

        Unload();

        bool result = false;
        SDL_RWops * rw = SDL_RWFromFile(path, "rb");
        if (rw != nullptr)
        {
            uint32 numSounds;
            SDL_RWread(rw, &numSounds, sizeof(numSounds), 1);
            if (index < numSounds)
            {
                SDL_RWseek(rw, index * 4, RW_SEEK_CUR);

                uint32 pcmOffset;
                SDL_RWread(rw, &pcmOffset, sizeof(pcmOffset), 1);
                SDL_RWseek(rw, pcmOffset, RW_SEEK_SET);

                uint32 pcmSize;
                SDL_RWread(rw, &pcmSize, sizeof(pcmSize), 1);
                _length = pcmSize;

                WaveFormatEx waveFormat;
                SDL_RWread(rw, &waveFormat, sizeof(waveFormat), 1);
                _format.freq = waveFormat.frequency;
                _format.format = AUDIO_S16LSB;
                _format.channels = waveFormat.channels;

                _data = new (std::nothrow) uint8[_length];
                if (_data != nullptr)
                {
                    SDL_RWread(rw, _data, _length, 1);
                    result = true;
                }
                else
                {
                    log_verbose("Unable to allocate data");
                }
            }
            SDL_RWclose(rw);
        }
        else
        {
            log_verbose("Unable to load %s", path);
        }
        return result;
    }

    bool Convert(const AudioFormat * format)
    {
        if (*format != _format)
        {
            SDL_AudioCVT cvt;
            if (SDL_BuildAudioCVT(&cvt, _format.format, _format.channels, _format.freq, format->format, format->channels, format->freq) >= 0)
            {
                cvt.len = (int)_length;
                cvt.buf = new uint8[cvt.len * cvt.len_mult];
                Memory::Copy(cvt.buf, _data, _length);
                if (SDL_ConvertAudio(&cvt) >= 0)
                {
                    Unload();
                    _data = cvt.buf;
                    _length = cvt.len_cvt;
                    _format = *format;
                    return true;
                }
                else
                {
                    delete[] cvt.buf;
                }
            }
        }
        return false;
    }

private:
    void Unload()
    {
        if (_data != nullptr)
        {
            if (_isSDLWav)
            {
                SDL_FreeWAV(_data);
            }
            else
            {
                delete[] _data;
            }
            _data = nullptr;
        }
        _isSDLWav = false;
        _length = 0;
    }
};

IAudioSource * AudioSource::CreateMemoryFromCSS1(const utf8 * path, size_t index, const AudioFormat * targetFormat)
{
    auto source = new MemoryAudioSource();
    if (source->LoadCSS1(path, index))
    {
        if (targetFormat != nullptr)
        {
            if (!source->Convert(targetFormat))
            {
                SafeDelete(source);
            }
        }
    }
    else
    {
        SafeDelete(source);
    }
    return source;
}

IAudioSource * AudioSource::CreateMemoryFromWAV(const utf8 * path, const AudioFormat * targetFormat)
{
    auto source = new MemoryAudioSource();
    if (source->LoadWAV(path))
    {
        if (targetFormat != nullptr)
        {
            if (!source->Convert(targetFormat))
            {
                SafeDelete(source);
            }
        }
    }
    else
    {
        SafeDelete(source);
    }
    return source;
}