axmol/core/audio/AudioDecoderMp3.h

/****************************************************************************
 Copyright (c) 2016 Chukong Technologies Inc.
 Copyright (c) 2017-2018 Xiamen Yaji Software Co., Ltd.
 Copyright (c) 2021 Bytedance Inc.

 https://axmolengine.github.io/

 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
 in the Software without restriction, including without limitation the rights
 to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 copies of the Software, and to permit persons to whom the Software is
 furnished to do so, subject to the following conditions:

 The above copyright notice and this permission notice shall be included in
 all copies or substantial portions of the Software.

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 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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 LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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 ****************************************************************************/

#pragma once

#include "audio/AudioDecoder.h"
#include <memory>

#if !defined(AX_USE_MPG123)
#    define AX_USE_MPG123 0
#endif

#if !AX_USE_MPG123
typedef struct mp3dec_impl* mp3dec_handle_t;
#else
typedef struct mpg123_handle_struct* mp3dec_handle_t;
#endif

NS_AX_BEGIN

/**
 * @brief The class for decoding compressed audio file to PCM buffer.
 */
class AudioDecoderMp3 : public AudioDecoder
{
public:
    /**
     * @brief Opens an audio file specified by a file path.
     * @return true if succeed, otherwise false.
     */
    bool open(std::string_view path) override;

    /**
     * @brief Closes opened audio file.
     * @note The method will also be automatically invoked in the destructor.
     */
    void close() override;

    /**
     * @brief Reads audio frames of PCM format.
     * @param framesToRead The number of frames excepted to be read.
     * @param pcmBuf The buffer to hold the frames to be read, its size should be >= |framesToRead| / samplesPerBlock *
     * _bytesPerBlock.
     * @return The number of frames actually read, it's probably less than 'framesToRead'. Returns 0 means reach the end
     * of file.
     */
    uint32_t read(uint32_t framesToRead, char* pcmBuf) override;

    /**
     * @brief Sets frame offest to be read.
     * @param frameOffset The frame offest to be set.
     * @return true if succeed, otherwise false
     */
    bool seek(uint32_t frameOffset) override;

protected:
    AudioDecoderMp3();
    ~AudioDecoderMp3();

    static bool lazyInit();
    static void destroy();

    std::unique_ptr<FileStream> _fileStream{};
    mp3dec_handle_t _handle;

    friend class AudioDecoderManager;
};

NS_AX_END  // namespace ax