axmol/core/audio/AudioDecoderEXT.h

/****************************************************************************
 Copyright (c) 2016 Chukong Technologies Inc.
 Copyright (c) 2017-2018 Xiamen Yaji Software Co., Ltd.
 Copyright (c) 2018 HALX99.

 https://axmolengine.github.io/

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 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 <stdint.h>
#import <AudioToolbox/ExtendedAudioFile.h>
#include "audio/AudioDecoder.h"
#include "platform/FileStream.h"

NS_AX_BEGIN

/**
 * @brief The class for decoding compressed audio file to PCM buffer.
 */
class AudioDecoderEXT : public AudioDecoder
{
public:
    static const uint32_t INVALID_FRAME_INDEX = UINT32_MAX;

    AudioDecoderEXT();
    ~AudioDecoderEXT();

    /**
     * @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 Reads fixed 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.
     * @note The different between |read| and |readFixedFrames| is |readFixedFrames| will do multiple reading operations
     * if |framesToRead| frames isn't filled entirely, while |read| just does reading operation once whatever
     * |framesToRead| is or isn't filled entirely. If current position reaches the end of frames, the return value may
     * smaller than |framesToRead| and the remaining buffer in |pcmBuf| will be set with silence data (0x00).
     */
    // uint32_t readFixedFrames(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;

private:
    void closeInternal();

    static OSStatus readCallback(void* inClientData,
                                 SInt64 inPosition,
                                 UInt32 requestCount,
                                 void* buffer,
                                 UInt32* actualCount);
    static SInt64 getSizeCallback(void* inClientData);

    ExtAudioFileRef _extRef;
    std::unique_ptr<ax::FileStream> _fileStream;
    SInt64 _streamSize;
    AudioFileID _audioFileId;

    AudioStreamBasicDescription _outputFormat;
};

NS_AX_END  // namespace ax