/**

 * Scan a single directory (and recursively it's children) and add

 * any graphics sets that are found.

 * @param extension       the extension of files to search for.

 * @param path            full path we're currently at

 * @param basepath_length from where in the path are we 'based' on the search path

 */

static uint ScanPath(FileScanner *fs, const char *extension, const char *path, size_t basepath_length)

{

	extern bool FiosIsValidFile(const char *path, const struct dirent *ent, struct stat *sb);

	uint num = 0;

	struct stat sb;

	struct dirent *dirent;

	DIR *dir;

	if (path == NULL || (dir = ttd_opendir(path)) == NULL) return 0;

	while ((dirent = readdir(dir)) != NULL) {

		const char *d_name = FS2OTTD(dirent->d_name);

		char filename[MAX_PATH];

		if (!FiosIsValidFile(path, dirent, &sb)) continue;

		snprintf(filename, lengthof(filename), "%s%s", path, d_name);

		if (sb.st_mode & S_IFDIR) {

			/* Directory */

			if (strcmp(d_name, ".") == 0 || strcmp(d_name, "..") == 0) continue;

			AppendPathSeparator(filename, lengthof(filename));

			num += ScanPath(fs, extension, filename, basepath_length);

		} else if (sb.st_mode & S_IFREG) {

			/* File */

			char *ext = strrchr(filename, '.');

			/* If no extension or extension isn't .grf, skip the file */

			if (ext == NULL) continue;

			if (strcasecmp(ext, extension) != 0) continue;

			if (fs->AddFile(filename, basepath_length)) num++;

		}

	}

	closedir(dir);

	return num;

}

/**

 * Scan the given tar and add graphics sets when it finds one.

 * @param extension the extension of files to search for.

 * @param tar       the tar to search in.

 */

static uint ScanTar(FileScanner *fs, const char *extension, TarFileList::iterator tar)

{

	uint num = 0;

	const char *filename = (*tar).first.c_str();

	const char *ext = strrchr(filename, '.');

	/* If no extension or extension isn't .grf, skip the file */

	if (ext == NULL) return false;

	if (strcasecmp(ext, extension) != 0) return false;

	if (fs->AddFile(filename, 0)) num++;

	return num;

}

/**

 * Scan for files with the given extention in the given search path.

 * @param extension the extension of files to search for.

 * @param sp        the sub directory to search in.

 * @param tars      whether to search in the tars too.

 * @return the number of found files, i.e. the number of times that

 *         AddFile returned true.

 */

uint FileScanner::Scan(const char *extension, Subdirectory sd, bool tars)

{

	Searchpath sp;

	char path[MAX_PATH];

	TarFileList::iterator tar;

	uint num = 0;

	FOR_ALL_SEARCHPATHS(sp) {

		FioAppendDirectory(path, MAX_PATH, sp, sd);

		num += ScanPath(this, extension, path, strlen(path));

	}

	FOR_ALL_TARS(tar) {

		num += ScanTar(this, extension, tar);

	}

	return num;

}

/** Helper for scanning for files with a given name */

class FileScanner

{

public:

	uint Scan(const char *extension, Subdirectory sd, bool tars = true);

	/**

	 * Add a file with the given filename.

	 * @param filename        the full path to the file to read

	 * @param basepath_length amount of characters to chop of before to get a

	 *                        filename relative to the search path.

	 * @return true if the file is added.

	 */

	virtual bool AddFile(const char *filename, size_t basepath_length) = 0;

};

/** Helper for scanning for files with GRF as extension */

class GRFFileScanner : FileScanner {

public:

	/* virtual */ bool AddFile(const char *filename, size_t basepath_length);

	/** Do the scan for GRFs. */

	static uint DoScan()

	{

		GRFFileScanner fs;

		return fs.Scan(".grf", DATA_DIR);

	}

};

bool GRFFileScanner::AddFile(const char *filename, size_t basepath_length)

	c->filename = strdup(filename + basepath_length);

	uint num = GRFFileScanner::DoScan();