private static List parseStandardHeader()

in utils/src/main/java/org/apache/felix/utils/resource/ResourceBuilder.java [1006:1122]
113 lines of code
33 McCabe index (conditional complexity)

    private static List<ParsedHeaderClause> parseStandardHeader(String header) {
        List<ParsedHeaderClause> clauses = new ArrayList<>();
        if (header == null) {
            return clauses;
        }
        ParsedHeaderClause clause = null;
        String key = null;
        Map targetMap = null;
        int state = CLAUSE_START;
        int currentPosition = 0;
        int startPosition = 0;
        int length = header.length();
        boolean quoted = false;
        boolean escaped = false;

        char currentChar;
        do {
            currentChar = charAt(currentPosition, header, length);
            switch (state) {
            case CLAUSE_START:
                clause = new ParsedHeaderClause();
                clauses.add(clause);
                // Fall through
            case PARAMETER_START:
                startPosition = currentPosition;
                state = KEY;
                // Fall through
            case KEY:
                switch (currentChar) {
                case ':':
                case '=':
                    key = header.substring(startPosition, currentPosition).trim();
                    startPosition = currentPosition + 1;
                    targetMap = clause.attrs;
                    state = currentChar == ':' ? DIRECTIVE_OR_TYPEDATTRIBUTE : ARGUMENT;
                    break;
                case EOF:
                case ',':
                case ';':
                    clause.paths.add(header.substring(startPosition, currentPosition).trim());
                    state = currentChar == ',' ? CLAUSE_START : PARAMETER_START;
                    break;
                default:
                    break;
                }
                currentPosition++;
                break;
            case DIRECTIVE_OR_TYPEDATTRIBUTE:
                switch (currentChar) {
                case '=':
                    if (startPosition != currentPosition) {
                        clause.types.put(key, header.substring(startPosition, currentPosition).trim());
                    } else {
                        targetMap = clause.dirs;
                    }
                    state = ARGUMENT;
                    startPosition = currentPosition + 1;
                    break;
                default:
                    break;
                }
                currentPosition++;
                break;
            case ARGUMENT:
                if (currentChar == '\"') {
                    quoted = true;
                    currentPosition++;
                } else {
                    quoted = false;
                }
                if (!Character.isWhitespace(currentChar)) {
                    state = VALUE;
                } else {
                    currentPosition++;
                }
                break;
            case VALUE:
                if (escaped) {
                    escaped = false;
                } else {
                    if (currentChar == '\\') {
                        escaped = true;
                    } else if (quoted && currentChar == '\"') {
                        quoted = false;
                    } else if (!quoted) {
                        String value;
                        switch (currentChar) {
                        case EOF:
                        case ';':
                        case ',':
                            value = header.substring(startPosition, currentPosition).trim();
                            if (value.startsWith("\"") && value.endsWith("\"")) {
                                value = value.substring(1, value.length() - 1);
                            }
                            if (targetMap.put(key, value) != null) {
                                throw new IllegalArgumentException(
                                        "Duplicate '" + key + "' in: " + header);
                            }
                            state = currentChar == ';' ? PARAMETER_START : CLAUSE_START;
                            break;
                        default:
                            break;
                        }
                    }
                }
                currentPosition++;
                break;
            default:
                break;
            }
        } while (currentChar != EOF);

        if (state > PARAMETER_START) {
            throw new IllegalArgumentException("Unable to parse header: " + header);
        }
        return clauses;
    }