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petitparser/lib/src/core/characters.dart

-part of petitparser;
-
-/**
- * Parser class for individual character classes.
- */
-class CharacterParser extends Parser {
-  final CharacterPredicate _predicate;
-
-  final String _message;
-
-  CharacterParser(this._predicate, this._message);
-
-  @override
-  Result parseOn(Context context) {
-    var buffer = context.buffer;
-    var position = context.position;
-    if (position < buffer.length &&
-        _predicate.test(buffer.codeUnitAt(position))) {
-      return context.success(buffer[position], position + 1);
-    }
-    return context.failure(_message);
-  }
-
-  @override
-  String toString() => '${super.toString()}[$_message]';
-
-  @override
-  Parser copy() => new CharacterParser(_predicate, _message);
-
-  @override
-  bool hasEqualProperties(Parser other) {
-    return other is CharacterParser
-        && super.hasEqualProperties(other)
-        && _predicate == other._predicate
-        && _message == other._message;
-  }
-}
-
-/**
- * Abstract character predicate class.
- */
-abstract class CharacterPredicate {
-
-  /**
-   * Tests if the character predicate is satisfied.
-   */
-  bool test(int value);
-}
-
-class _NotCharacterPredicate implements CharacterPredicate {
-  final CharacterPredicate predicate;
-
-  _NotCharacterPredicate(this.predicate);
-
-  @override
-  bool test(int value) => !predicate.test(value);
-}
-
-/**
- * Returns a parser that accepts any of the specified characters.
- */
-Parser anyOf(String string, [String message]) {
-  return new CharacterParser(_optimizedString(string),
-      message != null ? message : 'any of "$string" expected');
-}
-
-CharacterPredicate _optimizedString(String string) {
-  var ranges =
-      string.codeUnits.map((value) => new _RangeCharPredicate(value, value));
-  return _optimizedRanges(ranges);
-}
-
-CharacterPredicate _optimizedRanges(Iterable<_RangeCharPredicate> ranges) {
-
-  // 1. sort the ranges
-  var sortedRanges = new List.from(ranges, growable: false);
-  sortedRanges.sort((first, second) {
-    return first.start != second.start
-        ? first.start - second.start
-        : first.stop - second.stop;
-  });
-
-  // 2. merge adjacent or overlapping ranges
-  var mergedRanges = new List();
-  for (var thisRange in sortedRanges) {
-    if (mergedRanges.isEmpty) {
-      mergedRanges.add(thisRange);
-    } else {
-      var lastRange = mergedRanges.last;
-      if (lastRange.stop + 1 >= thisRange.start) {
-        var characterRange = new _RangeCharPredicate(lastRange.start, thisRange.stop);
-        mergedRanges[mergedRanges.length - 1] = characterRange;
-      } else {
-        mergedRanges.add(thisRange);
-      }
-    }
-  }
-
-  // 3. build the best resulting predicates
-  if (mergedRanges.length == 1) {
-    return mergedRanges[0].start == mergedRanges[0].stop
-        ? new _SingleCharPredicate(mergedRanges[0].start)
-        : mergedRanges[0];
-  } else {
-    return new _RangesCharPredicate(mergedRanges.length,
-        mergedRanges.map((range) => range.start).toList(growable: false),
-        mergedRanges.map((range) => range.stop).toList(growable: false));
-  }
-}
-
-/**
- * Returns a parser that accepts none of the specified characters.
- */
-Parser noneOf(String string, [String message]) {
-  return new CharacterParser(
-      new _NotCharacterPredicate(_optimizedString(string)),
-      message != null ? message : 'none of "$string" expected');
-}
-
-/**
- * Returns a parser that accepts a specific character only.
- */
-Parser char(element, [String message]) {
-  return new CharacterParser(new _SingleCharPredicate(_toCharCode(element)),
-      message != null ? message : '"$element" expected');
-}
-
-class _SingleCharPredicate implements CharacterPredicate {
-  final int value;
-
-  const _SingleCharPredicate(this.value);
-
-  @override
-  bool test(int value) => identical(this.value, value);
-}
-
-/**
- * Returns a parser that accepts any digit character.
- */
-Parser digit([String message]) {
-  return new CharacterParser(
-      _digitCharPredicate, message != null ? message : 'digit expected');
-}
-
-class _DigitCharPredicate implements CharacterPredicate {
-  const _DigitCharPredicate();
-
-  @override
-  bool test(int value) => 48 <= value && value <= 57;
-}
-
-const _digitCharPredicate = const _DigitCharPredicate();
-
-/**
- * Returns a parser that accepts any letter character.
- */
-Parser letter([String message]) {
-  return new CharacterParser(
-      _letterCharPredicate, message != null ? message : 'letter expected');
-}
-
-class _LetterCharPredicate implements CharacterPredicate {
-  const _LetterCharPredicate();
-
-  @override
-  bool test(int value) =>
-      (65 <= value && value <= 90) || (97 <= value && value <= 122);
-}
-
-const _letterCharPredicate = const _LetterCharPredicate();
-
-/**
- * Returns a parser that accepts any lowercase character.
- */
-Parser lowercase([String message]) {
-  return new CharacterParser(_lowercaseCharPredicate,
-      message != null ? message : 'lowercase letter expected');
-}
-
-class _LowercaseCharPredicate implements CharacterPredicate {
-  const _LowercaseCharPredicate();
-
-  @override
-  bool test(int value) => 97 <= value && value <= 122;
-}
-
-const _lowercaseCharPredicate = const _LowercaseCharPredicate();
-
-/**
- * Returns a parser that accepts the given character class pattern.
- */
-Parser pattern(String element, [String message]) {
-  return new CharacterParser(_patternParser.parse(element).value,
-      message != null ? message : '[$element] expected');
-}
-
-Parser _createPatternParser() {
-  var single = any().map(
-      (each) => new _RangeCharPredicate(_toCharCode(each), _toCharCode(each)));
-  var multiple = any().seq(char('-')).seq(any()).map((each) =>
-      new _RangeCharPredicate(_toCharCode(each[0]), _toCharCode(each[2])));
-  var positive =
-      multiple.or(single).plus().map((each) => _optimizedRanges(each));
-  return char('^').optional().seq(positive).map((each) =>
-      each[0] == null ? each[1] : new _NotCharacterPredicate(each[1]));
-}
-
-final _patternParser = _createPatternParser();
-
-class _RangesCharPredicate implements CharacterPredicate {
-  final int length;
-  final List<int> starts;
-  final List<int> stops;
-
-  _RangesCharPredicate(this.length, this.starts, this.stops);
-
-  @override
-  bool test(int value) {
-    var min = 0;
-    var max = length;
-    while (min < max) {
-      var mid = min + ((max - min) >> 1);
-      var comp = starts[mid] - value;
-      if (comp == 0) {
-        return true;
-      } else if (comp < 0) {
-        min = mid + 1;
-      } else {
-        max = mid;
-      }
-    }
-    return 0 < min && value <= stops[min - 1];
-  }
-}
-
-/**
- * Returns a parser that accepts any character in the range
- * between [start] and [stop].
- */
-Parser range(start, stop, [String message]) {
-  return new CharacterParser(
-      new _RangeCharPredicate(_toCharCode(start), _toCharCode(stop)),
-      message != null ? message : '$start..$stop expected');
-}
-
-class _RangeCharPredicate implements CharacterPredicate {
-  final int start;
-  final int stop;
-
-  _RangeCharPredicate(this.start, this.stop);
-
-  @override
-  bool test(int value) => start <= value && value <= stop;
-}
-
-/**
- * Returns a parser that accepts any uppercase character.
- */
-Parser uppercase([String message]) {
-  return new CharacterParser(_uppercaseCharPredicate,
-      message != null ? message : 'uppercase letter expected');
-}
-
-class _UppercaseCharPredicate implements CharacterPredicate {
-  const _UppercaseCharPredicate();
-
-  @override
-  bool test(int value) => 65 <= value && value <= 90;
-}
-
-const _uppercaseCharPredicate = const _UppercaseCharPredicate();
-
-/**
- * Returns a parser that accepts any whitespace character.
- */
-Parser whitespace([String message]) {
-  return new CharacterParser(_whitespaceCharPredicate,
-      message != null ? message : 'whitespace expected');
-}
-
-class _WhitespaceCharPredicate implements CharacterPredicate {
-  const _WhitespaceCharPredicate();
-
-  @override
-  bool test(int value) {
-    if (value < 256) {
-      return value == 0x09 ||
-          value == 0x0A ||
-          value == 0x0B ||
-          value == 0x0C ||
-          value == 0x0D ||
-          value == 0x20 ||
-          value == 0x85 ||
-          value == 0xA0;
-    } else {
-      return value == 0x1680 ||
-          value == 0x180E ||
-          value == 0x2000 ||
-          value == 0x2001 ||
-          value == 0x2002 ||
-          value == 0x2003 ||
-          value == 0x2004 ||
-          value == 0x2005 ||
-          value == 0x2006 ||
-          value == 0x2007 ||
-          value == 0x2008 ||
-          value == 0x2009 ||
-          value == 0x200A ||
-          value == 0x2028 ||
-          value == 0x2029 ||
-          value == 0x202F ||
-          value == 0x205F ||
-          value == 0x3000 ||
-          value == 0xFEFF;
-    }
-  }
-}
-
-const _whitespaceCharPredicate = const _WhitespaceCharPredicate();
-
-/**
- * Returns a parser that accepts any word character.
- */
-Parser word([String message]) {
-  return new CharacterParser(_wordCharPredicate,
-      message != null ? message : 'letter or digit expected');
-}
-
-class _WordCharPredicate implements CharacterPredicate {
-  const _WordCharPredicate();
-
-  @override
-  bool test(int value) => (65 <= value && value <= 90) ||
-      (97 <= value && value <= 122) ||
-      (48 <= value && value <= 57) ||
-      (value == 95);
-}
-
-const _wordCharPredicate = const _WordCharPredicate();
-
-// internal converter for character codes
-int _toCharCode(element) {
-  if (element is num) {
-    return element.round();
-  }
-  var value = element.toString();
-  if (value.length != 1) {
-    throw new ArgumentError('$value is not a character');
-  }
-  return value.codeUnitAt(0);
-}