recase.patch

diff --git a/lib/recase.dart b/lib/recase.dart
index da14cec..42a1251 100644
--- a/lib/recase.dart
+++ b/lib/recase.dart
@@ -1,44 +1,94 @@
+import 'dart:typed_data';
+
 /// An instance of text to be re-cased.
 class ReCase {
-  final RegExp _upperAlphaRegex = new RegExp(r'[A-Z]');
-  final RegExp _symbolRegex = new RegExp(r'[ ./_\-]');
-
-  String originalText;
-  List<String> _words;
-
-  ReCase(String text) {
-    this.originalText = text;
-    this._words = _groupIntoWords(text);
+  static const isLowerCase = 1;
+  static const isUpperCase = 2;
+  static const isSymbol = 3;
+  static final Uint8List mapping = (() {
+    final result = Uint8List(256);
+    for (var i = 'a'.codeUnitAt(0); i <= 'z'.codeUnitAt(0); i++) {
+      result[i] = isLowerCase;
+    }
+    for (var i = 'A'.codeUnitAt(0); i <= 'Z'.codeUnitAt(0); i++) {
+      result[i] = isUpperCase;
+    }
+    for (var i in ' ./_\-'.split('').map((e) => e.codeUnitAt(0))) {
+      result[i] = isSymbol;
+    }
+    return result;
+  })();
+
+  final String originalText;
+  final Uint16List codeUnits;
+  final List<int> _wordBoundaries;
+  final int _totalLength;
+  List<String> get _words {
+    List<String> words = List(_wordBoundaries.length >> 1);
+    for (var i = 0; i < _wordBoundaries.length; i += 2) {
+      words[i >> 1] =
+          (originalText.substring(_wordBoundaries[i], _wordBoundaries[i + 1]));
+    }
+    return words;
   }
 
-  List<String> _groupIntoWords(String text) {
-    StringBuffer sb = new StringBuffer();
-    List<String> words = [];
-    bool isAllCaps = !text.contains(RegExp('[a-z]'));
+  ReCase._(this.originalText, this.codeUnits, this._wordBoundaries, this._totalLength);
 
+  factory ReCase(String text) {
+    final Uint16List codeUnits = Uint16List(text.length);
     for (int i = 0; i < text.length; i++) {
-      String char = new String.fromCharCode(text.codeUnitAt(i));
-      String nextChar = (i + 1 == text.length
-          ? null
-          : new String.fromCharCode(text.codeUnitAt(i + 1)));
-
-      if (_symbolRegex.hasMatch(char)) {
-        continue;
-      }
+      codeUnits[i] = text.codeUnitAt(i);
+    }
 
-      sb.write(char);
+    List<int> words = [];
+    int total = 0;
 
-      bool isEndOfWord = nextChar == null ||
-          (_upperAlphaRegex.hasMatch(nextChar) && !isAllCaps) ||
-          _symbolRegex.hasMatch(nextChar);
+    bool isAllCaps = true;
+    for (int i = 0; i < codeUnits.length; i++) {
+      final ch = codeUnits[i];
+      if (ch < 256 && mapping[ch] == isLowerCase) {
+        isAllCaps = false;
+        break;
+      }
+    }
 
-      if (isEndOfWord) {
-        words.add(sb.toString());
-        sb.clear();
+    int wordStart = -1;
+    for (int i = 0; i < codeUnits.length; i++) {
+      final char = codeUnits[i];
+      if (char < 256) {
+        final type = mapping[char];
+        if (type == isSymbol) {
+          if (wordStart != -1) {
+            // We have a word, flush it out.
+            words.add(wordStart);
+            words.add(i);
+            total += (i - wordStart);
+            wordStart = -1;
+          }
+          continue;
+        } else if (type == isUpperCase && !isAllCaps) {
+          if (wordStart != -1) {
+            // We have a word, flush it out.
+            words.add(wordStart);
+            words.add(i);
+            total += (i - wordStart);
+
+          }
+          wordStart = i; // New word begins here.
+          continue;
+        }
+      }
+      if (wordStart == -1) {
+        wordStart = i;
       }
     }
+    if (wordStart != -1) {
+      words.add(wordStart);
+      words.add(codeUnits.length);
+      total += (codeUnits.length - wordStart);
+    }
 
-    return words;
+    return ReCase._(text, codeUnits, words, total);
   }
 
   /// camelCase
@@ -85,9 +135,43 @@ class ReCase {
   }
 
   String _getPascalCase({String separator: ''}) {
-    List<String> words = this._words.map(_upperCaseFirstLetter).toList();
-
-    return words.join(separator);
+    List<String> words =
+        List(_wordBoundaries.length + (_wordBoundaries.length >> 1) - 1);
+    if (separator.length == 1) {
+      final separatorChar = separator.codeUnitAt(0);
+      final result = Uint16List(_totalLength + (_wordBoundaries.length >> 1) - 1);
+      var out = 0;
+      for (var i = 0; i < _wordBoundaries.length; i += 2) {
+        if (i != 0) result[out++] = separatorChar;
+
+        final start = _wordBoundaries[i];
+        final end = _wordBoundaries[i+1];
+
+        int firstChar = codeUnits[start];
+        if (firstChar < 256 && mapping[firstChar] == isLowerCase) {
+          firstChar = firstChar ^ 32;
+        }
+        result[out++] = firstChar;
+
+        for (var j = start + 1; j < end; j++) {
+          int char = codeUnits[j];
+          if (char < 256 && mapping[char] == isUpperCase) {
+            char = char ^ 32;
+          }
+          result[out++] = char;
+        }
+      }
+      return String.fromCharCodes(result);
+    } else {
+      for (var i = 0, j = 0; i < _wordBoundaries.length; i += 2, j += 3) {
+        if (i != 0) words[j - 1] = separator;
+        words[j] = originalText[_wordBoundaries[i]].toUpperCase();
+        words[j + 1] = originalText
+            .substring(_wordBoundaries[i] + 1, _wordBoundaries[i + 1])
+            .toLowerCase();
+      }
+    }
+    return words.join('');
   }
 
   String _getSentenceCase({String separator: ' '}) {
@@ -109,7 +193,6 @@ class ReCase {
 }
 
 extension StringReCase on String {
-
   String get camelCase => ReCase(this).camelCase;
 
   String get constantCase => ReCase(this).constantCase;
diff --git a/pubspec.lock b/pubspec.lock
index 770e733..22625fd 100644
--- a/pubspec.lock
+++ b/pubspec.lock
@@ -7,49 +7,49 @@ packages:
       name: _fe_analyzer_shared
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.0.1"
+    version: "5.0.0"
   analyzer:
     dependency: transitive
     description:
       name: analyzer
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.39.2+1"
+    version: "0.39.12"
   args:
     dependency: transitive
     description:
       name: args
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.5.2"
+    version: "1.6.0"
   async:
     dependency: transitive
     description:
       name: async
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.4.0"
+    version: "2.4.2"
   boolean_selector:
     dependency: transitive
     description:
       name: boolean_selector
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.0.5"
+    version: "2.0.0"
   charcode:
     dependency: transitive
     description:
       name: charcode
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.1.2"
+    version: "1.1.3"
   collection:
     dependency: transitive
     description:
       name: collection
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.14.12"
+    version: "1.14.13"
   convert:
     dependency: transitive
     description:
@@ -63,14 +63,14 @@ packages:
       name: coverage
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.13.3+3"
+    version: "0.14.0"
   crypto:
     dependency: transitive
     description:
       name: crypto
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.1.4"
+    version: "2.1.5"
   csslib:
     dependency: transitive
     description:
@@ -98,56 +98,56 @@ packages:
       name: http
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.12.0+3"
+    version: "0.12.1"
   http_multi_server:
     dependency: transitive
     description:
       name: http_multi_server
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.1.0"
+    version: "2.2.0"
   http_parser:
     dependency: transitive
     description:
       name: http_parser
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "3.1.3"
+    version: "3.1.4"
   io:
     dependency: transitive
     description:
       name: io
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.3.3"
+    version: "0.3.4"
   js:
     dependency: transitive
     description:
       name: js
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.6.1+1"
+    version: "0.6.2"
   logging:
     dependency: transitive
     description:
       name: logging
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.11.3+2"
+    version: "0.11.4"
   matcher:
     dependency: transitive
     description:
       name: matcher
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.12.6"
+    version: "0.12.8"
   meta:
     dependency: transitive
     description:
       name: meta
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.1.8"
+    version: "1.2.1"
   mime:
     dependency: transitive
     description:
@@ -155,62 +155,48 @@ packages:
       url: "https://pub.dartlang.org"
     source: hosted
     version: "0.9.6+3"
-  multi_server_socket:
-    dependency: transitive
-    description:
-      name: multi_server_socket
-      url: "https://pub.dartlang.org"
-    source: hosted
-    version: "1.0.2"
   node_interop:
     dependency: transitive
     description:
       name: node_interop
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.0.3"
+    version: "1.1.1"
   node_io:
     dependency: transitive
     description:
       name: node_io
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.0.1+2"
+    version: "1.1.1"
   node_preamble:
     dependency: transitive
     description:
       name: node_preamble
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.4.8"
+    version: "1.4.12"
   package_config:
     dependency: transitive
     description:
       name: package_config
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.1.0"
-  package_resolver:
-    dependency: transitive
-    description:
-      name: package_resolver
-      url: "https://pub.dartlang.org"
-    source: hosted
-    version: "1.0.10"
+    version: "1.9.3"
   path:
     dependency: transitive
     description:
       name: path
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.6.4"
+    version: "1.7.0"
   pedantic:
     dependency: transitive
     description:
       name: pedantic
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.9.0"
+    version: "1.9.1"
   pool:
     dependency: transitive
     description:
@@ -224,21 +210,21 @@ packages:
       name: pub_semver
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.4.2"
+    version: "1.4.4"
   shelf:
     dependency: transitive
     description:
       name: shelf
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.7.5"
+    version: "0.7.7"
   shelf_packages_handler:
     dependency: transitive
     description:
       name: shelf_packages_handler
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.0.4"
+    version: "2.0.0"
   shelf_static:
     dependency: transitive
     description:
@@ -259,28 +245,28 @@ packages:
       name: source_map_stack_trace
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.1.5"
+    version: "2.0.0"
   source_maps:
     dependency: transitive
     description:
       name: source_maps
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.10.8"
+    version: "0.10.9"
   source_span:
     dependency: transitive
     description:
       name: source_span
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.5.5"
+    version: "1.7.0"
   stack_trace:
     dependency: transitive
     description:
       name: stack_trace
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.9.3"
+    version: "1.9.5"
   stream_channel:
     dependency: transitive
     description:
@@ -308,42 +294,42 @@ packages:
       name: test
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.9.4"
+    version: "1.15.2"
   test_api:
     dependency: transitive
     description:
       name: test_api
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.2.11"
+    version: "0.2.17"
   test_core:
     dependency: transitive
     description:
       name: test_core
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.2.15"
+    version: "0.3.10"
   typed_data:
     dependency: transitive
     description:
       name: typed_data
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.1.6"
+    version: "1.2.0"
   vm_service:
     dependency: transitive
     description:
       name: vm_service
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.2.1"
+    version: "4.1.0"
   watcher:
     dependency: transitive
     description:
       name: watcher
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.9.7+13"
+    version: "0.9.7+15"
   web_socket_channel:
     dependency: transitive
     description:
@@ -351,12 +337,19 @@ packages:
       url: "https://pub.dartlang.org"
     source: hosted
     version: "1.1.0"
+  webkit_inspection_protocol:
+    dependency: transitive
+    description:
+      name: webkit_inspection_protocol
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "0.7.3"
   yaml:
     dependency: transitive
     description:
       name: yaml
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.2.0"
+    version: "2.2.1"
 sdks:
-  dart: ">=2.6.0 <3.0.0"
+  dart: ">=2.7.0 <3.0.0"
diff --git a/pubspec.yaml b/pubspec.yaml
index 0cb2c76..d9b1b1f 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -5,4 +5,4 @@ homepage: https://github.com/techniboogie-dart/recase
 environment:
   sdk: '>=2.6.0 <3.0.0'
 dev_dependencies:
-  test: '^1.0.0'
+  test: any