public static String normalizeBranchName()

in org.eclipse.jgit/src/org/eclipse/jgit/lib/Repository.java [1451:1518]
62 lines of code
27 McCabe index (conditional complexity)

	public static String normalizeBranchName(String name) {
		if (name == null || name.isEmpty()) {
			return ""; //$NON-NLS-1$
		}
		String result = name.trim();
		String fullName = result.startsWith(Constants.R_HEADS) ? result
				: Constants.R_HEADS + result;
		if (isValidRefName(fullName)) {
			return result;
		}

		// All Unicode blanks to underscore
		result = result.replaceAll("(?:\\h|\\v)+", "_"); //$NON-NLS-1$ //$NON-NLS-2$
		StringBuilder b = new StringBuilder();
		char p = '/';
		for (int i = 0, len = result.length(); i < len; i++) {
			char c = result.charAt(i);
			if (c < ' ' || c == 127) {
				continue;
			}
			// Substitute a dash for problematic characters
			switch (c) {
			case '\\':
			case '^':
			case '~':
			case ':':
			case '?':
			case '*':
			case '[':
			case '@':
			case '<':
			case '>':
			case '|':
			case '"':
				c = '-';
				break;
			default:
				break;
			}
			// Collapse multiple slashes, dashes, dots, underscores, and omit
			// dashes, dots, and underscores following a slash.
			switch (c) {
			case '/':
				if (p == '/') {
					continue;
				}
				p = '/';
				break;
			case '.':
			case '_':
			case '-':
				if (p == '/' || p == '-') {
					continue;
				}
				p = '-';
				break;
			default:
				p = c;
				break;
			}
			b.append(c);
		}
		// Strip trailing special characters, and avoid the .lock extension
		result = b.toString().replaceFirst("[/_.-]+$", "") //$NON-NLS-1$ //$NON-NLS-2$
				.replaceAll("\\.lock($|/)", "_lock$1"); //$NON-NLS-1$ //$NON-NLS-2$
		return FORBIDDEN_BRANCH_NAME_COMPONENTS.matcher(result)
				.replaceAll("$1+$2$3"); //$NON-NLS-1$
	}