Avoid calling ByteData.setUint64.

lib/src/hash_sink.dart

Index: lib/src/hash_sink.dart
diff --git a/lib/src/hash_sink.dart b/lib/src/hash_sink.dart
index a3cef94c4a9a17c760072dd87a84bac3a5dce16b..f4adcb3da61e7ffee13c474d69b22c6eaa7bde45 100644
--- a/lib/src/hash_sink.dart
+++ b/lib/src/hash_sink.dart
@@ -128,7 +128,20 @@ abstract class HashSink implements Sink<List<int>> {
     // hash.
     var offset = _pendingData.length;
     _pendingData.addAll(new Uint8List(8));
-    _pendingData.buffer.asByteData().setUint64(offset, lengthInBits, _endian);
+    var byteData = _pendingData.buffer.asByteData();
+
+    // We're essentially doing byteData.setUint64(offset, lengthInBits, _endian)
+    // here, but that method isn't supported on dart2js so we implement it
+    // manually instead.
+    var highBits = lengthInBits >> 32;

[sra1, 2016/03/23 22:15:50]

This won't actually do what you want in dart2js.
dart2js bit operations assume the inputs are 32 bit unsigned values.
The result will always be zero.  It is probably always zero in practice.

You could use
 
   lengthInBits ~/ 4294967296

if you want it to work in JS for data of size 0.5GB.

[nweiz, 2016/03/23 22:21:26]

Presumably in dart2js, lengthInBits can't be higher than 2^32 anyway, right? 

+    var lowBits = lengthInBits & mask32;
+    if (_endian == Endianness.BIG_ENDIAN) {
+      byteData.setUint32(offset, highBits, _endian);
+      byteData.setUint32(offset + bytesPerWord, lowBits, _endian);
+    } else {
+      byteData.setUint32(offset, lowBits, _endian);
+      byteData.setUint32(offset + bytesPerWord, highBits, _endian);
+    }
   }
 
   /// Rounds [val] up to the next multiple of [n], as long as [n] is a power of