Move UTF-8 decoder to utils.

dart/utils/utf8/utf8.dart

-// Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
+// Copyright (c) 2012, 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.
 
-/**
- * An abstract string representation.
- */
-class ByteString implements SourceString {
+#library('utf8');
+
+class Utf8Decoder {
   final List<int> bytes;
   final int offset;
   final int length;
-  int _hashCode;
 
-  ByteString(List<int> this.bytes, int this.offset, int this.length);
-
-  abstract String get charset();
+  Utf8Decoder(List<int> this.bytes, int this.offset, int this.length);
 
   String toString() {
-    var list;
-    try {
-      list = bytes.getRange(offset, length);
-    } catch (var ignored) {
-      // An exception may occur when running this on node. This is
-      // because [bytes] really is a buffer (or typed array).
-      list = new List<int>(length);
-      for (int i = 0; i < length; i++) {
-        list[i] = bytes[i + offset];
-      }
-    }
-    return new String.fromCharCodes(decodeUtf8(list));
+    return new String.fromCharCodes(decodeUtf8(bytes.getRange(offset, length)));
   }
 
   static int decodeTrailing(int byte) {
     if (byte < 0x80 || 0xBF < byte) {
-      throw new MalformedInputException('Cannot decode UTF-8 $byte');
+      throw new Exception('Cannot decode UTF-8 $byte');
     } else {
       return byte & 0x3F;
     }
   }
 
   static List<int> decodeUtf8(List<int> bytes) {
     List<int> result = new List<int>();
     for (int i = 0; i < bytes.length; i++) {
       if (bytes[i] < 0x80) {
         result.add(bytes[i]);
       } else if (bytes[i] < 0xC2) {
-        throw new MalformedInputException('Cannot decode UTF-8 @ $i');
+        throw new Exception('Cannot decode UTF-8 @ $i');
       } else if (bytes[i] < 0xE0) {
         int char = (bytes[i++] & 0x1F) << 6;
         char += decodeTrailing(bytes[i]);
         if (char < 0x80) {
-          throw new MalformedInputException('Cannot decode UTF-8 @ ${i-1}');
+          throw new Exception('Cannot decode UTF-8 @ ${i-1}');
         } else {
           result.add(char);
         }
       } else if (bytes[i] < 0xF0) {
         int char = (bytes[i++] & 0x0F) << 6;
         char += decodeTrailing(bytes[i++]);
         char <<= 6;
         char += decodeTrailing(bytes[i]);
         if (char < 0x800 || (0xD800 <= char && char <= 0xDFFF)) {
-          throw new MalformedInputException('Cannot decode UTF-8 @ ${i-2}');
+          throw new Exception('Cannot decode UTF-8 @ ${i-2}');
         } else {
           result.add(char);
         }
       } else if (bytes[i] < 0xF8) {
         int char = (bytes[i++] & 0x07) << 6;
         char += decodeTrailing(bytes[i++]);
         char <<= 6;
         char += decodeTrailing(bytes[i++]);
         char <<= 6;
         char += decodeTrailing(bytes[i]);
         if (char < 0x10000) {
-          throw new MalformedInputException('Cannot decode UTF-8 @ ${i-3}');
+          throw new Exception('Cannot decode UTF-8 @ ${i-3}');
         } else {
           result.add(char);
         }
       } else {
-        throw new MalformedInputException('Cannot decode UTF-8 @ $i');
+        throw new Exception('Cannot decode UTF-8 @ $i');
       }
     }
     return result;
   }
-
-  bool operator ==(other) {
-    throw "should be overridden in subclass";
-  }
-
-  int hashCode() {
-    if (_hashCode === null) {
-      _hashCode = computeHashCode();
-    }
-    return _hashCode;
-  }
-
-  int computeHashCode() {
-    int code = 1;
-    int end = offset + length;
-    for (int i = offset; i < end; i++) {
-      code += 19 * code + bytes[i];
-    }
-    return code;
-  }
-
-  printOn(StringBuffer sb) {
-    sb.add(toString());
-  }
 }
-
-/**
- * A string that consists purely of 7bit ASCII characters.
- */
-class AsciiString extends ByteString {
-  final String charset = "ASCII";
-
-  AsciiString(List<int> bytes, int offset, int length)
-    : super(bytes, offset, length);
-
-  static AsciiString of(List<int> bytes, int offset, int length) {
-    AsciiString string = new AsciiString(bytes, offset, length);
-    return string;
-  }
-
-  static AsciiString fromString(String string) {
-    List<int> bytes = string.charCodes();
-    return AsciiString.of(bytes, 0, bytes.length);
-  }
-}
-
-/**
- * A string that consists of characters that can be encoded as UTF-8.
- */
-class Utf8String extends ByteString {
-  final String charset = "UTF8";
-
-  Utf8String(List<int> bytes, int offset, int length)
-    : super(bytes, offset, length);
-
-  static Utf8String of(List<int> bytes, int offset, int length) {
-    return new Utf8String(bytes, offset, length);
-  }
-
-  static Utf8String fromString(String string) {
-    throw "not implemented yet";
-  }
-}
-
-/**
- * A ByteString-valued token.
- */
-class ByteStringToken extends Token {
-  final ByteString value;
-
-  ByteStringToken(PrecedenceInfo info, ByteString this.value, int charOffset)
-    : super(info, charOffset);
-
-  String toString() => value.toString();
-}