diff --git a/js/binary/decoder_test.js b/js/binary/decoder_test.js
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+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+/**
+ * @fileoverview Test cases for jspb's binary protocol buffer decoder.
+ *
+ * There are two particular magic numbers that need to be pointed out -
+ * 2^64-1025 is the largest number representable as both a double and an
+ * unsigned 64-bit integer, and 2^63-513 is the largest number representable as
+ * both a double and a signed 64-bit integer.
+ *
+ * Test suite is written using Jasmine -- see http://jasmine.github.io/
+ *
+ * @author aappleby@google.com (Austin Appleby)
+ */
+
+goog.require('goog.testing.asserts');
+goog.require('jspb.BinaryConstants');
+goog.require('jspb.BinaryDecoder');
+goog.require('jspb.BinaryWriter');
+
+
+/**
+ * Tests raw encoding and decoding of unsigned types.
+ * @param {Function} readValue
+ * @param {Function} writeValue
+ * @param {number} epsilon
+ * @param {number} upperLimit
+ * @param {Function} filter
+ * @suppress {missingProperties|visibility}
+ */
+function doTestUnsignedValue(readValue,
+    writeValue, epsilon, upperLimit, filter) {
+  var writer = new jspb.BinaryWriter();
+
+  // Encode zero and limits.
+  writeValue.call(writer, filter(0));
+  writeValue.call(writer, filter(epsilon));
+  writeValue.call(writer, filter(upperLimit));
+
+  // Encode positive values.
+  for (var cursor = epsilon; cursor < upperLimit; cursor *= 1.1) {
+    writeValue.call(writer, filter(cursor));
+  }
+
+  var reader = jspb.BinaryDecoder.alloc(writer.getResultBuffer());
+
+  // Check zero and limits.
+  assertEquals(filter(0), readValue.call(reader));
+  assertEquals(filter(epsilon), readValue.call(reader));
+  assertEquals(filter(upperLimit), readValue.call(reader));
+
+  // Check positive values.
+  for (var cursor = epsilon; cursor < upperLimit; cursor *= 1.1) {
+    if (filter(cursor) != readValue.call(reader)) throw 'fail!';
+  }
+}
+
+
+/**
+ * Tests raw encoding and decoding of signed types.
+ * @param {Function} readValue
+ * @param {Function} writeValue
+ * @param {number} epsilon
+ * @param {number} lowerLimit
+ * @param {number} upperLimit
+ * @param {Function} filter
+ * @suppress {missingProperties}
+ */
+function doTestSignedValue(readValue,
+    writeValue, epsilon, lowerLimit, upperLimit, filter) {
+  var writer = new jspb.BinaryWriter();
+
+  // Encode zero and limits.
+  writeValue.call(writer, filter(lowerLimit));
+  writeValue.call(writer, filter(-epsilon));
+  writeValue.call(writer, filter(0));
+  writeValue.call(writer, filter(epsilon));
+  writeValue.call(writer, filter(upperLimit));
+
+  var inputValues = [];
+
+  // Encode negative values.
+  for (var cursor = lowerLimit; cursor < -epsilon; cursor /= 1.1) {
+    var val = filter(cursor);
+    writeValue.call(writer, val);
+    inputValues.push(val);
+  }
+
+  // Encode positive values.
+  for (var cursor = epsilon; cursor < upperLimit; cursor *= 1.1) {
+    var val = filter(cursor);
+    writeValue.call(writer, val);
+    inputValues.push(val);
+  }
+
+  var reader = jspb.BinaryDecoder.alloc(writer.getResultBuffer());
+
+  // Check zero and limits.
+  assertEquals(filter(lowerLimit), readValue.call(reader));
+  assertEquals(filter(-epsilon), readValue.call(reader));
+  assertEquals(filter(0), readValue.call(reader));
+  assertEquals(filter(epsilon), readValue.call(reader));
+  assertEquals(filter(upperLimit), readValue.call(reader));
+
+  // Verify decoded values.
+  for (var i = 0; i < inputValues.length; i++) {
+    assertEquals(inputValues[i], readValue.call(reader));
+  }
+}
+
+describe('binaryDecoderTest', function() {
+  /**
+   * Tests the decoder instance cache.
+   * @suppress {visibility}
+   */
+  it('testInstanceCache', function() {
+    // Empty the instance caches.
+    jspb.BinaryDecoder.instanceCache_ = [];
+
+    // Allocating and then freeing a decoder should put it in the instance
+    // cache.
+    jspb.BinaryDecoder.alloc().free();
+
+    assertEquals(1, jspb.BinaryDecoder.instanceCache_.length);
+
+    // Allocating and then freeing three decoders should leave us with three in
+    // the cache.
+
+    var decoder1 = jspb.BinaryDecoder.alloc();
+    var decoder2 = jspb.BinaryDecoder.alloc();
+    var decoder3 = jspb.BinaryDecoder.alloc();
+    decoder1.free();
+    decoder2.free();
+    decoder3.free();
+
+    assertEquals(3, jspb.BinaryDecoder.instanceCache_.length);
+  });
+
+
+  /**
+   * Tests reading 64-bit integers as hash strings.
+   */
+  it('testHashStrings', function() {
+    var writer = new jspb.BinaryWriter();
+
+    var hashA = String.fromCharCode(0x00, 0x00, 0x00, 0x00,
+                                    0x00, 0x00, 0x00, 0x00);
+    var hashB = String.fromCharCode(0x12, 0x34, 0x00, 0x00,
+                                    0x00, 0x00, 0x00, 0x00);
+    var hashC = String.fromCharCode(0x12, 0x34, 0x56, 0x78,
+                                    0x87, 0x65, 0x43, 0x21);
+    var hashD = String.fromCharCode(0xFF, 0xFF, 0xFF, 0xFF,
+                                    0xFF, 0xFF, 0xFF, 0xFF);
+
+    writer.rawWriteVarintHash64(hashA);
+    writer.rawWriteVarintHash64(hashB);
+    writer.rawWriteVarintHash64(hashC);
+    writer.rawWriteVarintHash64(hashD);
+
+    writer.rawWriteFixedHash64(hashA);
+    writer.rawWriteFixedHash64(hashB);
+    writer.rawWriteFixedHash64(hashC);
+    writer.rawWriteFixedHash64(hashD);
+
+    var decoder = jspb.BinaryDecoder.alloc(writer.getResultBuffer());
+
+    assertEquals(hashA, decoder.readVarintHash64());
+    assertEquals(hashB, decoder.readVarintHash64());
+    assertEquals(hashC, decoder.readVarintHash64());
+    assertEquals(hashD, decoder.readVarintHash64());
+
+    assertEquals(hashA, decoder.readFixedHash64());
+    assertEquals(hashB, decoder.readFixedHash64());
+    assertEquals(hashC, decoder.readFixedHash64());
+    assertEquals(hashD, decoder.readFixedHash64());
+  });
+
+
+  /**
+   * Verifies that misuse of the decoder class triggers assertions.
+   * @suppress {checkTypes|visibility}
+   */
+  it('testDecodeErrors', function() {
+    // Reading a value past the end of the stream should trigger an assertion.
+    var decoder = jspb.BinaryDecoder.alloc([0, 1, 2]);
+    assertThrows(function() {decoder.readUint64()});
+
+    // Overlong varints should trigger assertions.
+    decoder.setBlock(
+        [255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 0]);
+    assertThrows(function() {decoder.readUnsignedVarint64()});
+    decoder.reset();
+    assertThrows(function() {decoder.readSignedVarint64()});
+    decoder.reset();
+    assertThrows(function() {decoder.readZigzagVarint64()});
+
+    // Positive 32-bit varints encoded with 1 bits in positions 33 through 35
+    // should trigger assertions.
+    decoder.setBlock([255, 255, 255, 255, 0x1F]);
+    assertThrows(function() {decoder.readUnsignedVarint32()});
+
+    decoder.setBlock([255, 255, 255, 255, 0x2F]);
+    assertThrows(function() {decoder.readUnsignedVarint32()});
+
+    decoder.setBlock([255, 255, 255, 255, 0x4F]);
+    assertThrows(function() {decoder.readUnsignedVarint32()});
+
+    // Negative 32-bit varints encoded with non-1 bits in the high dword should
+    // trigger assertions.
+    decoder.setBlock([255, 255, 255, 255, 255, 255, 0, 255, 255, 1]);
+    assertThrows(function() {decoder.readUnsignedVarint32()});
+
+    decoder.setBlock([255, 255, 255, 255, 255, 255, 255, 255, 255, 0]);
+    assertThrows(function() {decoder.readUnsignedVarint32()});
+  });
+
+
+  /**
+   * Tests raw encoding and decoding of unsigned integers.
+   */
+  it('testRawUnsigned', function() {
+    doTestUnsignedValue(
+        jspb.BinaryDecoder.prototype.readUint8,
+        jspb.BinaryWriter.prototype.rawWriteUint8,
+        1, 0xFF, Math.round);
+
+    doTestUnsignedValue(
+        jspb.BinaryDecoder.prototype.readUint16,
+        jspb.BinaryWriter.prototype.rawWriteUint16,
+        1, 0xFFFF, Math.round);
+
+    doTestUnsignedValue(
+        jspb.BinaryDecoder.prototype.readUint32,
+        jspb.BinaryWriter.prototype.rawWriteUint32,
+        1, 0xFFFFFFFF, Math.round);
+
+    doTestUnsignedValue(
+        jspb.BinaryDecoder.prototype.readUint64,
+        jspb.BinaryWriter.prototype.rawWriteUint64,
+        1, Math.pow(2, 64) - 1025, Math.round);
+  });
+
+
+  /**
+   * Tests raw encoding and decoding of signed integers.
+   */
+  it('testRawSigned', function() {
+    doTestSignedValue(
+        jspb.BinaryDecoder.prototype.readInt8,
+        jspb.BinaryWriter.prototype.rawWriteInt8,
+        1, -0x80, 0x7F, Math.round);
+
+    doTestSignedValue(
+        jspb.BinaryDecoder.prototype.readInt16,
+        jspb.BinaryWriter.prototype.rawWriteInt16,
+        1, -0x8000, 0x7FFF, Math.round);
+
+    doTestSignedValue(
+        jspb.BinaryDecoder.prototype.readInt32,
+        jspb.BinaryWriter.prototype.rawWriteInt32,
+        1, -0x80000000, 0x7FFFFFFF, Math.round);
+
+    doTestSignedValue(
+        jspb.BinaryDecoder.prototype.readInt64,
+        jspb.BinaryWriter.prototype.rawWriteInt64,
+        1, -Math.pow(2, 63), Math.pow(2, 63) - 513, Math.round);
+  });
+
+
+  /**
+   * Tests raw encoding and decoding of floats.
+   */
+  it('testRawFloats', function() {
+    /**
+     * @param {number} x
+     * @return {number}
+     */
+    function truncate(x) {
+      var temp = new Float32Array(1);
+      temp[0] = x;
+      return temp[0];
+    }
+    doTestSignedValue(
+        jspb.BinaryDecoder.prototype.readFloat,
+        jspb.BinaryWriter.prototype.rawWriteFloat,
+        jspb.BinaryConstants.FLOAT32_EPS,
+        -jspb.BinaryConstants.FLOAT32_MAX,
+        jspb.BinaryConstants.FLOAT32_MAX,
+        truncate);
+
+    doTestSignedValue(
+        jspb.BinaryDecoder.prototype.readDouble,
+        jspb.BinaryWriter.prototype.rawWriteDouble,
+        jspb.BinaryConstants.FLOAT64_EPS * 10,
+        -jspb.BinaryConstants.FLOAT64_MAX,
+        jspb.BinaryConstants.FLOAT64_MAX,
+        function(x) { return x; });
+  });
+});