解图片存到Mat

Mat Canvas::http_get_image(string url)
{
	//http://192.168.0.129/cache/convert/58d17d693f85fb3708f95da032e4342e/0.png

	string host = "";
	string port = "80";
	string page = "";
	size_t datalen = 0;

	int p2 = 0;
	for (int i = 0; i < 2; i++)
	{
		p2 = url.find('/', i == 0 ? 0 : p2 + 1);
		if (p2 == -1)
		{
			std::cout << "该字符似乎没有出现这么多次" << std::endl;
			break;
		}

	}
	int p3 = 0;
	for (int i = 0; i < 3; i++)
	{
		p3 = url.find('/', i == 0 ? 0 : p3 + 1);
		if (p3 == -1)
		{
			std::cout << "该字符似乎没有出现这么多次" << std::endl;
			break;
		}

	}

	host = url.substr(p2 + 1, p3 - p2 - 1);
	page = url.substr(p3, url.length() - p3);

	uint8_t * inImage = get(host, port, page, datalen);

	Mat image;
	if (datalen != 0)
	{
		std::vector<unsigned char> buff;
		for (int i = 0; i < datalen; i++)
		{
			buff.push_back(inImage[i]);
		}
		image = imdecode(Mat(buff), CV_LOAD_IMAGE_COLOR);

	}
	else
	{
		cout << "没有读到文件" << endl;
	}

	return image;
}