Use iterator, moveNext(), current.

sdk/lib/utf/utf16.dart

Index: sdk/lib/utf/utf16.dart
diff --git a/sdk/lib/utf/utf16.dart b/sdk/lib/utf/utf16.dart
index 431d695ad83a233f5e8130f82264945a07788d5e..7d318aaf2c1fe2f1638b24d4e315c9b368ad3238 100644
--- a/sdk/lib/utf/utf16.dart
+++ b/sdk/lib/utf/utf16.dart
@@ -221,7 +221,7 @@ class IterableUtf16Decoder extends Iterable<int> {
 
   IterableUtf16Decoder._(this.codeunitsProvider, this.replacementCodepoint);
 
-  Utf16CodeUnitDecoder iterator() =>
+  Utf16CodeUnitDecoder get iterator =>
       new Utf16CodeUnitDecoder.fromListRangeIterator(codeunitsProvider(),
           replacementCodepoint);
 }
@@ -234,6 +234,7 @@ class IterableUtf16Decoder extends Iterable<int> {
 class Utf16BytesToCodeUnitsDecoder implements _ListRangeIterator {
   final _ListRangeIterator utf16EncodedBytesIterator;
   final int replacementCodepoint;
+  int _current = -1;
 
   Utf16BytesToCodeUnitsDecoder._fromListRangeIterator(
       this.utf16EncodedBytesIterator, this.replacementCodepoint);
@@ -264,8 +265,8 @@ class Utf16BytesToCodeUnitsDecoder implements _ListRangeIterator {
   List<int> decodeRest() {
     List<int> codeunits = new List<int>(remaining);
     int i = 0;
-    while (hasNext) {
-      codeunits[i++] = next();
+    while (moveNext()) {
+      codeunits[i++] = current;
     }
     if (i == codeunits.length) {
       return codeunits;
@@ -276,19 +277,27 @@ class Utf16BytesToCodeUnitsDecoder implements _ListRangeIterator {
     }
   }
 
-  bool get hasNext => utf16EncodedBytesIterator.hasNext;
+  int get current {
+    if (_current == -1) {
+      // TODO(floitsch): bad error message.
+      throw new StateError("No more elements");
+    }
+  }
 
-  int next() {
+  bool moveNext() {
+    _current = -1;
     if (utf16EncodedBytesIterator.remaining < 2) {
-      utf16EncodedBytesIterator.next();
+      utf16EncodedBytesIterator.moveNext();
       if (replacementCodepoint != null) {
-        return replacementCodepoint;
+        _current = replacementCodepoint;
+        return true;
       } else {
         throw new ArgumentError(
             "Invalid UTF16 at ${utf16EncodedBytesIterator.position}");
       }
     } else {
-      return decode();
+      _current = decode();
+      return true;
     }
   }
 
@@ -315,16 +324,19 @@ class Utf16beBytesToCodeUnitsDecoder extends Utf16BytesToCodeUnitsDecoder {
   Utf16beBytesToCodeUnitsDecoder(List<int> utf16EncodedBytes, [
       int offset = 0, int length, bool stripBom = true,
       int replacementCodepoint = UNICODE_REPLACEMENT_CHARACTER_CODEPOINT]) :
-      super._fromListRangeIterator((new _ListRange(utf16EncodedBytes, offset,
-      length)).iterator(), replacementCodepoint) {
+      super._fromListRangeIterator(
+          (new _ListRange(utf16EncodedBytes, offset, length)).iterator,
+          replacementCodepoint) {
     if (stripBom && hasUtf16beBom(utf16EncodedBytes, offset, length)) {
       skip();
     }
   }
 
   int decode() {
-    int hi = utf16EncodedBytesIterator.next();
-    int lo = utf16EncodedBytesIterator.next();
+    utf16EncodedBytesIterator.moveNext();
+    int hi = utf16EncodedBytesIterator.current;
+    utf16EncodedBytesIterator.moveNext();
+    int lo = utf16EncodedBytesIterator.current;
     return (hi << 8) + lo;
   }
 }
@@ -337,16 +349,19 @@ class Utf16leBytesToCodeUnitsDecoder extends Utf16BytesToCodeUnitsDecoder {
   Utf16leBytesToCodeUnitsDecoder(List<int> utf16EncodedBytes, [
       int offset = 0, int length, bool stripBom = true,
       int replacementCodepoint = UNICODE_REPLACEMENT_CHARACTER_CODEPOINT]) :
-      super._fromListRangeIterator((new _ListRange(utf16EncodedBytes, offset,
-      length)).iterator(), replacementCodepoint) {
+      super._fromListRangeIterator(
+          (new _ListRange(utf16EncodedBytes, offset, length)).iterator,
+          replacementCodepoint) {
     if (stripBom && hasUtf16leBom(utf16EncodedBytes, offset, length)) {
       skip();
     }
   }
 
   int decode() {
-    int lo = utf16EncodedBytesIterator.next();
-    int hi = utf16EncodedBytesIterator.next();
+    utf16EncodedBytesIterator.moveNext();
+    int lo = utf16EncodedBytesIterator.current;
+    utf16EncodedBytesIterator.moveNext();
+    int hi = utf16EncodedBytesIterator.current;
     return (hi << 8) + lo;
   }
 }