RedCore/cocos2d/cocos/audio/win32/AudioDecoderMp3.cpp

/****************************************************************************
 Copyright (c) 2016-2017 Chukong Technologies Inc.

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#include "audio/win32/AudioDecoderMp3.h"
#include "audio/win32/AudioMacros.h"
#include "platform/CCFileUtils.h"

#include "base/CCConsole.h"
#include "mpg123.h"

#define LOG_TAG "AudioDecoderMp3"

namespace cocos2d { namespace experimental {

    static bool __mp3Inited = false;

    bool AudioDecoderMp3::lazyInit()
    {
        bool ret = true;
        if (!__mp3Inited)
        {
            int error = mpg123_init();
            if (error == MPG123_OK)
            {
                __mp3Inited = true;
            }
            else
            {
                ALOGE("Basic setup goes wrong: %s", mpg123_plain_strerror(error));
                ret = false;
            }
        }
        return ret;
    }

    void AudioDecoderMp3::destroy()
    {
        if (__mp3Inited)
        {
            mpg123_exit();
            __mp3Inited = false;
        }
    }

    AudioDecoderMp3::AudioDecoderMp3()
    : _mpg123handle(nullptr)
    {
        lazyInit();
    }

    AudioDecoderMp3::~AudioDecoderMp3()
    {
        close();
    }

    bool AudioDecoderMp3::open(const char* path)
    {
        std::string fullPath = FileUtils::getInstance()->fullPathForFilename(path);

        long rate = 0;
        int error = MPG123_OK;
        int mp3Encoding = 0;
        int channel = 0;
        do
        {
            _mpg123handle = mpg123_new(nullptr, &error);
            if (nullptr == _mpg123handle)
            {
                ALOGE("Basic setup goes wrong: %s", mpg123_plain_strerror(error));
                break;
            }

            if (mpg123_open(_mpg123handle, fullPath.c_str()) != MPG123_OK
                || mpg123_getformat(_mpg123handle, &rate, &channel, &mp3Encoding) != MPG123_OK)
            {
                ALOGE("Trouble with mpg123: %s\n", mpg123_strerror(_mpg123handle) );
                break;
            }

            _channelCount = channel;
            _sampleRate = rate;

            if (mp3Encoding == MPG123_ENC_SIGNED_16)
            {
                _bytesPerFrame = 2 * _channelCount;
            }
            else if (mp3Encoding == MPG123_ENC_FLOAT_32)
            {
                _bytesPerFrame = 4 * _channelCount;
            }
            else
            {
                ALOGE("Bad encoding: 0x%x!\n", mp3Encoding);
                break;
            }

            /* Ensure that this output format will not change (it could, when we allow it). */
            mpg123_format_none(_mpg123handle);
            mpg123_format(_mpg123handle, rate, channel, mp3Encoding);
            /* Ensure that we can get accurate length by call mpg123_length */
            mpg123_scan(_mpg123handle);

            _totalFrames = mpg123_length(_mpg123handle);

            _isOpened = true;
            return true;
        } while (false);

        if (_mpg123handle != nullptr)
        {
            mpg123_close(_mpg123handle);
            mpg123_delete(_mpg123handle);
            _mpg123handle = nullptr;
        }
        return false;
    }

    void AudioDecoderMp3::close()
    {
        if (isOpened())
        {
            if (_mpg123handle != nullptr)
            {
                mpg123_close(_mpg123handle);
                mpg123_delete(_mpg123handle);
                _mpg123handle = nullptr;
            }
            _isOpened = false;
        }
    }

    uint32_t AudioDecoderMp3::read(uint32_t framesToRead, char* pcmBuf)
    {
        int bytesToRead = framesToRead * _bytesPerFrame;
        size_t bytesRead = 0;
        int err = mpg123_read(_mpg123handle, (unsigned char*)pcmBuf, bytesToRead, &bytesRead);
        if (err == MPG123_ERR)
        {
            ALOGE("Trouble with mpg123: %s\n", mpg123_strerror(_mpg123handle) );
            return 0;
        }

        return static_cast<uint32_t>(bytesRead / _bytesPerFrame);
    }

    bool AudioDecoderMp3::seek(uint32_t frameOffset)
    {
        off_t offset = mpg123_seek(_mpg123handle, frameOffset, SEEK_SET);
        //ALOGD("mpg123_seek return: %d", (int)offset);
        if (offset >= 0 && offset == frameOffset)
        {
            return true;
        }
        return false;
    }

    uint32_t AudioDecoderMp3::tell() const
    {
        return static_cast<uint32_t>(mpg123_tell(_mpg123handle));
    }

}} // namespace cocos2d { namespace experimental {