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love-canvas_getPixel / src / modules / sound / lullaby / Mpg123Decoder.cpp

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/**
 * Copyright (c) 2006-2012 LOVE Development Team
 *
 * This software is provided 'as-is', without any express or implied
 * warranty.  In no event will the authors be held liable for any damages
 * arising from the use of this software.
 *
 * Permission is granted to anyone to use this software for any purpose,
 * including commercial applications, and to alter it and redistribute it
 * freely, subject to the following restrictions:
 *
 * 1. The origin of this software must not be misrepresented; you must not
 *    claim that you wrote the original software. If you use this software
 *    in a product, an acknowledgment in the product documentation would be
 *    appreciated but is not required.
 * 2. Altered source versions must be plainly marked as such, and must not be
 *    misrepresented as being the original software.
 * 3. This notice may not be removed or altered from any source distribution.
 **/

#ifndef LOVE_NOMPG123

#include "Mpg123Decoder.h"

#include "common/Exception.h"

#include <iostream>

namespace love
{
namespace sound
{
namespace lullaby
{

bool Mpg123Decoder::inited = false;

Mpg123Decoder::Mpg123Decoder(Data *data, const std::string &ext, int bufferSize)
	: Decoder(data, ext, bufferSize)
	, handle(0)
	, channels(MPG123_STEREO)
{

	data_size = data->getSize();
	data_offset = 0;

	int ret;

	if (!inited)
	{
		ret = mpg123_init();
		if (ret != MPG123_OK)
			throw love::Exception("Could not initialize mpg123.");
		inited = (ret == MPG123_OK);
	}

	//Intialize the handle
	handle = mpg123_new(NULL, &ret);
	if (handle == NULL)
		throw love::Exception("Could not create handle.");
	ret = mpg123_open_feed(handle);
	if (ret != MPG123_OK)
		throw love::Exception("Could not open feed.");

	ret = feed(16384);

	if (ret != MPG123_OK && ret != MPG123_DONE)
		throw love::Exception("Could not feed!");
}

Mpg123Decoder::~Mpg123Decoder()
{
	mpg123_delete(handle);

}

bool Mpg123Decoder::accepts(const std::string &ext)
{
	static const std::string supported[] =
	{
		"mp3", ""
	};

	for (int i = 0; !(supported[i].empty()); i++)
	{
		if (supported[i].compare(ext) == 0)
			return true;
	}

	return false;
}

void Mpg123Decoder::quit()
{
	if (inited)
		mpg123_exit();
}

love::sound::Decoder *Mpg123Decoder::clone()
{
	return new Mpg123Decoder(data, ext, bufferSize);
}

int Mpg123Decoder::decode()
{
	int size = 0;
	bool done = false;

	while (size < bufferSize && !done && !eof)
	{
		size_t numbytes = 0;

		int r = mpg123_read(handle, (unsigned char *) buffer + size, bufferSize - size, &numbytes);

		switch (r)
		{
		case MPG123_NEW_FORMAT:
		{
			size += numbytes;
			long rate = 0;
			int encoding = 0;
			int ret = mpg123_getformat(handle, &rate, &channels, &encoding);
			if (rate == 0)
				rate = sampleRate;
			else
				sampleRate = rate;
			if (channels == 0)
				channels = MPG123_STEREO;
			if (encoding == 0)
				encoding = MPG123_ENC_SIGNED_16;
			ret = mpg123_format(handle, rate, channels, encoding);
			if (ret != MPG123_OK)
				throw love::Exception("Could not set output format.");
		}
		continue;
		case MPG123_NEED_MORE:
		{
			size += numbytes;
			int v = feed(8192);

			switch (v)
			{
			case MPG123_OK:
				continue;
			case MPG123_DONE:
				if (numbytes == 0)
					eof = true;
				break;
			default:
				done = true;
			}

			continue;
		}
		case MPG123_OK:
			size += numbytes;
			continue;
		case MPG123_DONE:
			// Apparently, mpg123_read does not return MPG123_DONE, but
			// let's keep it here anyway.
			eof = true;
		default:
			done = true;
			break;
		}
	}

	return size;
}

bool Mpg123Decoder::seek(float s)
{
	off_t offset = static_cast<off_t>(s * static_cast<float>(sampleRate));

	if (offset < 0)
		return false;

	if (mpg123_feedseek(handle, offset, SEEK_SET, &offset) >= 0)
	{
		data_offset = offset;
		eof = false;
		return true;
	}
	else
		return false;
}

bool Mpg123Decoder::rewind()
{
	eof = false;
	off_t offset;

	if (mpg123_feedseek(handle, 0, SEEK_SET, &offset) >= 0)
	{
		data_offset = offset;
		return true;
	}
	else
		return false;
}

bool Mpg123Decoder::isSeekable()
{
	return true;
}

int Mpg123Decoder::getChannels() const
{
	return channels;
}

int Mpg123Decoder::getBits() const
{
	return 16;
}

int Mpg123Decoder::feed(int bytes)
{
	int remaining = data_size - data_offset;

	if (remaining <= 0)
		return MPG123_DONE;

	int feed_bytes = remaining < bytes ? remaining : bytes;

	int r = mpg123_feed(handle, (unsigned char *)data->getData() + data_offset, feed_bytes);

	if (r == MPG123_OK || r == MPG123_DONE)
		data_offset += feed_bytes;

	return r;
}

} // lullaby
} // sound
} // love

#endif // LOVE_NOMPG123