Parsing id3 title, album, artist info using mpg123

parse_id3.cpp

// returns a size-3 vector of: (title, artist, album)
std::vector<std::string> CST_GetMusicInfo(Mix_Music* music) {
	std::vector<std::string> info;
	// these three methods require a recent (late 2019) sdl_mixer verison
	// info.push_back(Mix_GetMusicTitle(music));
	// info.push_back(Mix_GetMusicArtistTag(music));
	// info.push_back(Mix_GetMusicAlbumTag(music));

	// adapted from https://gist.github.com/deepakjois/988032/640b7a41b0e62a394515697c142777ad3a1b8905
	auto m = mpg123_new(NULL, NULL);
	mpg123_open(m, "./background.mp3");
	mpg123_scan(m);
	auto meta = mpg123_meta_check(m);

	mpg123_id3v1* v1;
	mpg123_id3v2* v2;

	if (meta == MPG123_ID3 && mpg123_id3(m, &v1, &v2) == MPG123_OK) {
		if (v2 != NULL) {
			// fmt.Println("ID3V2 tag found")
			info.push_back(v2->title && v2->title->p  ? v2->title->p  : "");
			info.push_back(v2->artist && v2->artist->p ? v2->artist->p : "");
			info.push_back(v2->album && v2->album->p  ? v2->album->p  : "");
			return info;
		}
		if (v1 != NULL) {
			// fmt.Println("ID3V1 tag found")
			info.push_back(v1->title[0]  ? v1->title  : "");
			info.push_back(v1->artist[0] ? v1->artist : "");
			info.push_back(v1->album[0]  ? v1->album  : "");
			return info;			
		}
	}

	info.push_back("background.mp3");
	info.push_back("");
	info.push_back("");
	return info;
}