axmol/core/audio/AudioDecoderMp3.h

/****************************************************************************
 Copyright (c) 2016 Chukong Technologies Inc.
 Copyright (c) 2017-2018 Xiamen Yaji Software Co., Ltd.
 Copyright (c) 2019-present Axmol Engine contributors (see AUTHORS.md).

 https://axmol.dev/

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 of this software and associated documentation files (the "Software"), to deal
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 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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#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<IFileStream> _fileStream{};
    mp3dec_handle_t _handle;

    friend class AudioDecoderManager;
};

NS_AX_END  // namespace ax