Fix UTF8 encoder for Unicode runes > 0xFFFF.

sdk/lib/convert/utf.dart

Index: sdk/lib/convert/utf.dart
diff --git a/sdk/lib/convert/utf.dart b/sdk/lib/convert/utf.dart
index 6abaa0519b959200fe49ec33d7df190bd23fc352..b350f7d5efab7583a474f7a7da2858b8741a2736 100644
--- a/sdk/lib/convert/utf.dart
+++ b/sdk/lib/convert/utf.dart
@@ -7,6 +7,9 @@ part of dart.convert;
 /** The Unicode Replacement character `U+FFFD` (�). */
 const UNICODE_REPLACEMENT_CHARACTER_RUNE = 0xFFFD;
 
+/** The Unicode Byte Order Marker (BOM) character `U+FEFF`. */
+const UNICODE_BOM_CHARACTER_RUNE = 0xFEFF;
+
 /**
  * An instance of the default implementation of the [Utf8Codec].
  *
@@ -48,6 +51,9 @@ class Utf8Codec extends Encoding {
    * Decodes the UTF-8 [codeUnits] (a list of unsigned 8-bit integers) to the
    * corresponding string.
    *
+   * If the [codeUnits] start with a leading [UNICODE_BOM_CHARACTER_RUNE] this

[Anders Johnsen, 2013/10/01 11:32:29]

Is this really happening? I don't see any usage of 'UNICODE_BOM_CHARACTER_RUNE'.

[floitsch, 2013/10/01 11:37:42]

There was a private copy of it. I removed that one.

+   * character is discarded.
+   *
    * If [allowMalformed] is `true` the decoder replaces invalid (or
    * unterminated) character sequences with the Unicode Replacement character
    * `U+FFFD` (�). Otherwise it throws a [FormatException].
@@ -303,6 +309,9 @@ class Utf8Decoder extends Converter<List<int>, String> {
   /**
    * Converts the UTF-8 [codeUnits] (a list of unsigned 8-bit integers) to the
    * corresponding string.
+   *
+   * If the [codeUnits] start with a leading [UNICODE_BOM_CHARACTER_RUNE] this
+   * character is discarded.
    */
   String convert(List<int> codeUnits) {
     StringBuffer buffer = new StringBuffer();
@@ -356,7 +365,7 @@ bool _isLeadSurrogate(int codeUnit) =>
 bool _isTailSurrogate(int codeUnit) =>
     (codeUnit & _SURROGATE_TAG_MASK) == _TAIL_SURROGATE_MIN;
 int _combineSurrogatePair(int lead, int tail) =>
-    0x10000 | ((lead & _SURROGATE_VALUE_MASK) << 10)
+    0x10000 + ((lead & _SURROGATE_VALUE_MASK) << 10)
             | (tail & _SURROGATE_VALUE_MASK);