diff --git a/js/binary/encoder.js b/js/binary/encoder.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 BinaryEncode defines methods for encoding Javascript values
+ * into arrays of bytes compatible with the Protocol Buffer wire format.
+ *
+ * @author aappleby@google.com (Austin Appleby)
+ */
+
+goog.provide('jspb.BinaryEncoder');
+
+goog.require('goog.asserts');
+goog.require('jspb.BinaryConstants');
+goog.require('jspb.utils');
+
+
+
+/**
+ * BinaryEncoder implements encoders for all the wire types specified in
+ * https://developers.google.com/protocol-buffers/docs/encoding.
+ *
+ * @constructor
+ * @struct
+ */
+jspb.BinaryEncoder = function() {
+  /** @private {!Array<number>} */
+  this.buffer_ = [];
+};
+
+
+/**
+ * @return {number}
+ */
+jspb.BinaryEncoder.prototype.length = function() {
+  return this.buffer_.length;
+};
+
+
+/**
+ * @return {!Array<number>}
+ */
+jspb.BinaryEncoder.prototype.end = function() {
+  var buffer = this.buffer_;
+  this.buffer_ = [];
+  return buffer;
+};
+
+
+/**
+ * Encodes a 64-bit integer in 32:32 split representation into its wire-format
+ * varint representation and stores it in the buffer.
+ * @param {number} lowBits The low 32 bits of the int.
+ * @param {number} highBits The high 32 bits of the int.
+ */
+jspb.BinaryEncoder.prototype.writeSplitVarint64 = function(lowBits, highBits) {
+  goog.asserts.assert(lowBits == Math.floor(lowBits));
+  goog.asserts.assert(highBits == Math.floor(highBits));
+  goog.asserts.assert((lowBits >= 0) &&
+                      (lowBits < jspb.BinaryConstants.TWO_TO_32));
+  goog.asserts.assert((highBits >= 0) &&
+                      (highBits < jspb.BinaryConstants.TWO_TO_32));
+
+  // Break the binary representation into chunks of 7 bits, set the 8th bit
+  // in each chunk if it's not the final chunk, and append to the result.
+  while (highBits > 0 || lowBits > 127) {
+    this.buffer_.push((lowBits & 0x7f) | 0x80);
+    lowBits = ((lowBits >>> 7) | (highBits << 25)) >>> 0;
+    highBits = highBits >>> 7;
+  }
+  this.buffer_.push(lowBits);
+};
+
+
+/**
+ * Encodes a 64-bit integer in 32:32 split representation into its wire-format
+ * fixed representation and stores it in the buffer.
+ * @param {number} lowBits The low 32 bits of the int.
+ * @param {number} highBits The high 32 bits of the int.
+ */
+jspb.BinaryEncoder.prototype.writeSplitFixed64 = function(lowBits, highBits) {
+  goog.asserts.assert(lowBits == Math.floor(lowBits));
+  goog.asserts.assert(highBits == Math.floor(highBits));
+  goog.asserts.assert((lowBits >= 0) &&
+                      (lowBits < jspb.BinaryConstants.TWO_TO_32));
+  goog.asserts.assert((highBits >= 0) &&
+                      (highBits < jspb.BinaryConstants.TWO_TO_32));
+  this.writeUint32(lowBits);
+  this.writeUint32(highBits);
+};
+
+
+/**
+ * Encodes a 32-bit unsigned integer into its wire-format varint representation
+ * and stores it in the buffer.
+ * @param {number} value The integer to convert.
+ */
+jspb.BinaryEncoder.prototype.writeUnsignedVarint32 = function(value) {
+  goog.asserts.assert(value == Math.floor(value));
+  goog.asserts.assert((value >= 0) &&
+                      (value < jspb.BinaryConstants.TWO_TO_32));
+
+  while (value > 127) {
+    this.buffer_.push((value & 0x7f) | 0x80);
+    value = value >>> 7;
+  }
+
+  this.buffer_.push(value);
+};
+
+
+/**
+ * Encodes a 32-bit signed integer into its wire-format varint representation
+ * and stores it in the buffer.
+ * @param {number} value The integer to convert.
+ */
+jspb.BinaryEncoder.prototype.writeSignedVarint32 = function(value) {
+  goog.asserts.assert(value == Math.floor(value));
+  goog.asserts.assert((value >= -jspb.BinaryConstants.TWO_TO_31) &&
+                      (value < jspb.BinaryConstants.TWO_TO_31));
+
+  // Use the unsigned version if the value is not negative.
+  if (value >= 0) {
+    this.writeUnsignedVarint32(value);
+    return;
+  }
+
+  // Write nine bytes with a _signed_ right shift so we preserve the sign bit.
+  for (var i = 0; i < 9; i++) {
+    this.buffer_.push((value & 0x7f) | 0x80);
+    value = value >> 7;
+  }
+
+  // The above loop writes out 63 bits, so the last byte is always the sign bit
+  // which is always set for negative numbers.
+  this.buffer_.push(1);
+};
+
+
+/**
+ * Encodes a 64-bit unsigned integer into its wire-format varint representation
+ * and stores it in the buffer. Integers that are not representable in 64 bits
+ * will be truncated.
+ * @param {number} value The integer to convert.
+ */
+jspb.BinaryEncoder.prototype.writeUnsignedVarint64 = function(value) {
+  goog.asserts.assert(value == Math.floor(value));
+  goog.asserts.assert((value >= 0) &&
+                      (value < jspb.BinaryConstants.TWO_TO_64));
+  jspb.utils.splitInt64(value);
+  this.writeSplitVarint64(jspb.utils.split64Low,
+                          jspb.utils.split64High);
+};
+
+
+/**
+ * Encodes a 64-bit signed integer into its wire-format varint representation
+ * and stores it in the buffer. Integers that are not representable in 64 bits
+ * will be truncated.
+ * @param {number} value The integer to convert.
+ */
+jspb.BinaryEncoder.prototype.writeSignedVarint64 = function(value) {
+  goog.asserts.assert(value == Math.floor(value));
+  goog.asserts.assert((value >= -jspb.BinaryConstants.TWO_TO_63) &&
+                      (value < jspb.BinaryConstants.TWO_TO_63));
+  jspb.utils.splitInt64(value);
+  this.writeSplitVarint64(jspb.utils.split64Low,
+                          jspb.utils.split64High);
+};
+
+
+/**
+ * Encodes a JavaScript integer into its wire-format, zigzag-encoded varint
+ * representation and stores it in the buffer.
+ * @param {number} value The integer to convert.
+ */
+jspb.BinaryEncoder.prototype.writeZigzagVarint32 = function(value) {
+  goog.asserts.assert(value == Math.floor(value));
+  goog.asserts.assert((value >= -jspb.BinaryConstants.TWO_TO_31) &&
+                      (value < jspb.BinaryConstants.TWO_TO_31));
+  this.writeUnsignedVarint32(((value << 1) ^ (value >> 31)) >>> 0);
+};
+
+
+/**
+ * Encodes a JavaScript integer into its wire-format, zigzag-encoded varint
+ * representation and stores it in the buffer. Integers not representable in 64
+ * bits will be truncated.
+ * @param {number} value The integer to convert.
+ */
+jspb.BinaryEncoder.prototype.writeZigzagVarint64 = function(value) {
+  goog.asserts.assert(value == Math.floor(value));
+  goog.asserts.assert((value >= -jspb.BinaryConstants.TWO_TO_63) &&
+                      (value < jspb.BinaryConstants.TWO_TO_63));
+  jspb.utils.splitZigzag64(value);
+  this.writeSplitVarint64(jspb.utils.split64Low,
+                          jspb.utils.split64High);
+};
+
+
+/**
+ * Encodes a JavaScript decimal string into its wire-format, zigzag-encoded
+ * varint representation and stores it in the buffer. Integers not representable
+ * in 64 bits will be truncated.
+ * @param {string} value The integer to convert.
+ */
+jspb.BinaryEncoder.prototype.writeZigzagVarint64String = function(value) {
+  // TODO(haberman): write lossless 64-bit zig-zag math.
+  this.writeZigzagVarint64(parseInt(value, 10));
+};
+
+
+/**
+ * Writes a 8-bit unsigned integer to the buffer. Numbers outside the range
+ * [0,2^8) will be truncated.
+ * @param {number} value The value to write.
+ */
+jspb.BinaryEncoder.prototype.writeUint8 = function(value) {
+  goog.asserts.assert(value == Math.floor(value));
+  goog.asserts.assert((value >= 0) && (value < 256));
+  this.buffer_.push((value >>> 0) & 0xFF);
+};
+
+
+/**
+ * Writes a 16-bit unsigned integer to the buffer. Numbers outside the
+ * range [0,2^16) will be truncated.
+ * @param {number} value The value to write.
+ */
+jspb.BinaryEncoder.prototype.writeUint16 = function(value) {
+  goog.asserts.assert(value == Math.floor(value));
+  goog.asserts.assert((value >= 0) && (value < 65536));
+  this.buffer_.push((value >>> 0) & 0xFF);
+  this.buffer_.push((value >>> 8) & 0xFF);
+};
+
+
+/**
+ * Writes a 32-bit unsigned integer to the buffer. Numbers outside the
+ * range [0,2^32) will be truncated.
+ * @param {number} value The value to write.
+ */
+jspb.BinaryEncoder.prototype.writeUint32 = function(value) {
+  goog.asserts.assert(value == Math.floor(value));
+  goog.asserts.assert((value >= 0) &&
+                      (value < jspb.BinaryConstants.TWO_TO_32));
+  this.buffer_.push((value >>> 0) & 0xFF);
+  this.buffer_.push((value >>> 8) & 0xFF);
+  this.buffer_.push((value >>> 16) & 0xFF);
+  this.buffer_.push((value >>> 24) & 0xFF);
+};
+
+
+/**
+ * Writes a 64-bit unsigned integer to the buffer. Numbers outside the
+ * range [0,2^64) will be truncated.
+ * @param {number} value The value to write.
+ */
+jspb.BinaryEncoder.prototype.writeUint64 = function(value) {
+  goog.asserts.assert(value == Math.floor(value));
+  goog.asserts.assert((value >= 0) &&
+                      (value < jspb.BinaryConstants.TWO_TO_64));
+  jspb.utils.splitUint64(value);
+  this.writeUint32(jspb.utils.split64Low);
+  this.writeUint32(jspb.utils.split64High);
+};
+
+
+/**
+ * Writes a 8-bit integer to the buffer. Numbers outside the range
+ * [-2^7,2^7) will be truncated.
+ * @param {number} value The value to write.
+ */
+jspb.BinaryEncoder.prototype.writeInt8 = function(value) {
+  goog.asserts.assert(value == Math.floor(value));
+  goog.asserts.assert((value >= -128) && (value < 128));
+  this.buffer_.push((value >>> 0) & 0xFF);
+};
+
+
+/**
+ * Writes a 16-bit integer to the buffer. Numbers outside the range
+ * [-2^15,2^15) will be truncated.
+ * @param {number} value The value to write.
+ */
+jspb.BinaryEncoder.prototype.writeInt16 = function(value) {
+  goog.asserts.assert(value == Math.floor(value));
+  goog.asserts.assert((value >= -32768) && (value < 32768));
+  this.buffer_.push((value >>> 0) & 0xFF);
+  this.buffer_.push((value >>> 8) & 0xFF);
+};
+
+
+/**
+ * Writes a 32-bit integer to the buffer. Numbers outside the range
+ * [-2^31,2^31) will be truncated.
+ * @param {number} value The value to write.
+ */
+jspb.BinaryEncoder.prototype.writeInt32 = function(value) {
+  goog.asserts.assert(value == Math.floor(value));
+  goog.asserts.assert((value >= -jspb.BinaryConstants.TWO_TO_31) &&
+                      (value < jspb.BinaryConstants.TWO_TO_31));
+  this.buffer_.push((value >>> 0) & 0xFF);
+  this.buffer_.push((value >>> 8) & 0xFF);
+  this.buffer_.push((value >>> 16) & 0xFF);
+  this.buffer_.push((value >>> 24) & 0xFF);
+};
+
+
+/**
+ * Writes a 64-bit integer to the buffer. Numbers outside the range
+ * [-2^63,2^63) will be truncated.
+ * @param {number} value The value to write.
+ */
+jspb.BinaryEncoder.prototype.writeInt64 = function(value) {
+  goog.asserts.assert(value == Math.floor(value));
+  goog.asserts.assert((value >= -jspb.BinaryConstants.TWO_TO_63) &&
+                      (value < jspb.BinaryConstants.TWO_TO_63));
+  jspb.utils.splitInt64(value);
+  this.writeSplitFixed64(jspb.utils.split64Low, jspb.utils.split64High);
+};
+
+
+/**
+ * Writes a 64-bit integer decimal strings to the buffer. Numbers outside the
+ * range [-2^63,2^63) will be truncated.
+ * @param {string} value The value to write.
+ */
+jspb.BinaryEncoder.prototype.writeInt64String = function(value) {
+  goog.asserts.assert(value == Math.floor(value));
+  goog.asserts.assert((+value >= -jspb.BinaryConstants.TWO_TO_63) &&
+                      (+value < jspb.BinaryConstants.TWO_TO_63));
+  jspb.utils.splitHash64(jspb.utils.decimalStringToHash64(value));
+  this.writeSplitFixed64(jspb.utils.split64Low, jspb.utils.split64High);
+};
+
+
+/**
+ * Writes a single-precision floating point value to the buffer. Numbers
+ * requiring more than 32 bits of precision will be truncated.
+ * @param {number} value The value to write.
+ */
+jspb.BinaryEncoder.prototype.writeFloat = function(value) {
+  goog.asserts.assert((value >= -jspb.BinaryConstants.FLOAT32_MAX) &&
+                      (value <= jspb.BinaryConstants.FLOAT32_MAX));
+  jspb.utils.splitFloat32(value);
+  this.writeUint32(jspb.utils.split64Low);
+};
+
+
+/**
+ * Writes a double-precision floating point value to the buffer. As this is
+ * the native format used by JavaScript, no precision will be lost.
+ * @param {number} value The value to write.
+ */
+jspb.BinaryEncoder.prototype.writeDouble = function(value) {
+  goog.asserts.assert((value >= -jspb.BinaryConstants.FLOAT64_MAX) &&
+                      (value <= jspb.BinaryConstants.FLOAT64_MAX));
+  jspb.utils.splitFloat64(value);
+  this.writeUint32(jspb.utils.split64Low);
+  this.writeUint32(jspb.utils.split64High);
+};
+
+
+/**
+ * Writes a boolean value to the buffer as a varint. We allow numbers as input
+ * because the JSPB code generator uses 0/1 instead of true/false to save space
+ * in the string representation of the proto.
+ * @param {boolean|number} value The value to write.
+ */
+jspb.BinaryEncoder.prototype.writeBool = function(value) {
+  goog.asserts.assert(goog.isBoolean(value) || goog.isNumber(value));
+  this.buffer_.push(value ? 1 : 0);
+};
+
+
+/**
+ * Writes an enum value to the buffer as a varint.
+ * @param {number} value The value to write.
+ */
+jspb.BinaryEncoder.prototype.writeEnum = function(value) {
+  goog.asserts.assert(value == Math.floor(value));
+  goog.asserts.assert((value >= -jspb.BinaryConstants.TWO_TO_31) &&
+                      (value < jspb.BinaryConstants.TWO_TO_31));
+  this.writeSignedVarint32(value);
+};
+
+
+/**
+ * Writes an arbitrary byte array to the buffer.
+ * @param {!Uint8Array} bytes The array of bytes to write.
+ */
+jspb.BinaryEncoder.prototype.writeBytes = function(bytes) {
+  this.buffer_.push.apply(this.buffer_, bytes);
+};
+
+
+/**
+ * Writes a 64-bit hash string (8 characters @ 8 bits of data each) to the
+ * buffer as a varint.
+ * @param {string} hash The hash to write.
+ */
+jspb.BinaryEncoder.prototype.writeVarintHash64 = function(hash) {
+  jspb.utils.splitHash64(hash);
+  this.writeSplitVarint64(jspb.utils.split64Low,
+                          jspb.utils.split64High);
+};
+
+
+/**
+ * Writes a 64-bit hash string (8 characters @ 8 bits of data each) to the
+ * buffer as a fixed64.
+ * @param {string} hash The hash to write.
+ */
+jspb.BinaryEncoder.prototype.writeFixedHash64 = function(hash) {
+  jspb.utils.splitHash64(hash);
+  this.writeUint32(jspb.utils.split64Low);
+  this.writeUint32(jspb.utils.split64High);
+};
+
+
+/**
+ * Writes a UTF16 Javascript string to the buffer encoded as UTF8.
+ * TODO(aappleby): Add support for surrogate pairs, reject unpaired surrogates.
+ * @param {string} value The string to write.
+ * @return {number} The number of bytes used to encode the string.
+ */
+jspb.BinaryEncoder.prototype.writeString = function(value) {
+  var oldLength = this.buffer_.length;
+
+  for (var i = 0; i < value.length; i++) {
+
+    var c = value.charCodeAt(i);
+
+    if (c < 128) {
+      this.buffer_.push(c);
+    } else if (c < 2048) {
+      this.buffer_.push((c >> 6) | 192);
+      this.buffer_.push((c & 63) | 128);
+    } else if (c < 65536) {
+      // Look for surrogates
+      if (c >= 0xD800 && c <= 0xDBFF && i + 1 < value.length) {
+        var second = value.charCodeAt(i + 1);
+        if (second >= 0xDC00 && second <= 0xDFFF) { // low surrogate
+          // http://mathiasbynens.be/notes/javascript-encoding#surrogate-formulae
+          c = (c - 0xD800) * 0x400 + second - 0xDC00 + 0x10000;
+
+          this.buffer_.push((c >> 18) | 240);
+          this.buffer_.push(((c >> 12) & 63 ) | 128);
+          this.buffer_.push(((c >> 6) & 63) | 128);
+          this.buffer_.push((c & 63) | 128);
+          i++;
+        }
+      }
+      else {
+        this.buffer_.push((c >> 12) | 224);
+        this.buffer_.push(((c >> 6) & 63) | 128);
+        this.buffer_.push((c & 63) | 128);
+      }
+    }
+  }
+
+  var length = this.buffer_.length - oldLength;
+  return length;
+};