axmol/cocos/audio/include/AudioDecoderMp3.h

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

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#pragma once

#include "audio/include/AudioDecoder.h"
#include "platform/PXFileStream.h"

struct mpg123_handle_struct;

namespace cocos2d {

/**
 * @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.
     */
    virtual bool open(const char* path) override;

    /**
     * @brief Closes opened audio file.
     * @note The method will also be automatically invoked in the destructor.
     */
    virtual 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| * _bytesPerFrame.
     * @return The number of frames actually read, it's probably less than 'framesToRead'. Returns 0 means reach the end of file.
     */
    virtual 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
     */
    virtual bool seek(uint32_t frameOffset) override;

    /**
     * @brief Tells the current frame offset.
     * @return The current frame offset.
     */
    virtual uint32_t tell() const override;

protected:

    AudioDecoderMp3();
    ~AudioDecoderMp3();

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

    PXFileStream _fileStream;
    struct mpg123_handle_struct* _mpg123handle;

    friend class AudioDecoderManager;
};

} // namespace cocos2d {