| // Copyright (c) 2014, the Dart project authors. Please see the AUTHORS file |
| // for details. All rights reserved. Use of this source code is governed by a |
| // BSD-style license that can be found in the LICENSE file. |
| |
| /// Validates the arguments passed to [StringScanner.error]. |
| void validateErrorArgs(String string, Match match, int position, int length) { |
| if (match != null && (position != null || length != null)) { |
| throw new ArgumentError("Can't pass both match and position/length."); |
| } |
| |
| if (position != null) { |
| if (position < 0) { |
| throw new RangeError("position must be greater than or equal to 0."); |
| } else if (position > string.length) { |
| throw new RangeError("position must be less than or equal to the " |
| "string length."); |
| } |
| } |
| |
| if (length != null && length < 0) { |
| throw new RangeError("length must be greater than or equal to 0."); |
| } |
| |
| if (position != null && length != null && position + length > string.length) { |
| throw new RangeError("position plus length must not go beyond the end of " |
| "the string."); |
| } |
| } |