axmol/cocos/audio/win32/AudioDecoderMp3.cpp

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

 http://www.cocos2d-x.org

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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.

 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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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 {