// Copyright 2017 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
/**
 * @fileoverview Protocol Buffer 2 Serializer which serializes and deserializes
 * messages using the wire format. Note that this serializer requires protocol
 * buffer reflection, which carries some overhead.
 * @supported any browser with DataView implemented. For now Chrome9, FF15, IE10
 *
 * @see https://developers.google.com/protocol-buffers/docs/encoding
 *
 * TODO(feinberg): Replace goog.math.Long with mutable long representation that
 * permits in-place arithmetic to avoid allocations.
 */


goog.provide('net.proto2.contrib.WireSerializer');

goog.require('goog.array');
goog.require('goog.asserts');
goog.require('goog.math.Long');
goog.require('goog.proto2.Message');
goog.require('goog.proto2.Serializer');



/**
 * Wire format serializer.
 *
 * @constructor
 * @extends {goog.proto2.Serializer}
 */
net.proto2.contrib.WireSerializer = function() {
  /**
   * This array is where proto bytes go during serialization.
   * It must be reset for each serialization.
   * @type {!Array.<number>}
   * @private
   */
  this.buffer_ = [];

  /**
   * Scratch workspace to avoid allocations during serialization.
   * @type {{value: number, length: number}}
   * @private
   */
  this.scratchTag32_ = {value: 0, length: 0};

  /**
   * Scratch workspace to avoid allocations during serialization.
   * @type {{value: !goog.math.Long, length: number}}
   * @private
   */
  this.scratchTag64_ = {value: goog.math.Long.getZero(), length: 0};

  /**
   * Scratch data view for coding/decoding little-endian numbers.
   * @type {!DataView}
   * @private
   */
  this.dataView_ = new DataView(new ArrayBuffer(8));
};
goog.inherits(net.proto2.contrib.WireSerializer, goog.proto2.Serializer);


/**
 * @return {!Array.<number>} The serialized form of the message.
 * @override
 */
net.proto2.contrib.WireSerializer.prototype.serialize = function(message) {
  if (message == null) {
    return [];
  }

  this.buffer_ = [];

  var descriptor = message.getDescriptor();
  var fields = descriptor.getFields();

  // Add the known fields.
  for (var i = 0; i < fields.length; i++) {
    var field = fields[i];

    if (!message.has(field)) {
      continue;
    }

    if (field.isRepeated()) {
      if (field.isPacked()) {
        this.serializePackedField_(message, field);
      } else {
        for (var j = 0, n = message.countOf(field); j < n; j++) {
          var val = message.get(field, j);
          this.getSerializedValue(field, val);
        }
      }
    } else {
      this.getSerializedValue(field, message.get(field));
    }
  }

  return this.buffer_;
};


/**
 * Append the serialized packed field to our serialization buffer.
 * @param {!goog.proto2.Message} message The message containing the field
 *     to serialize.
 * @param {!goog.proto2.FieldDescriptor} field The field to serialize.
 * @return {boolean} Whether the field tag was serialized.
 * @private
 */
net.proto2.contrib.WireSerializer.prototype.serializePackedField_ =
    function(message, field) {
  var buf = this.buffer_;

  var wireType = 2;  // Per definition.

  // Tag.
  this.serializeVarint_((field.getTag() << 3) | wireType);

  // Make note of the current buffer size. After serializing the repeated
  // fields, splice the size header at the current position.
  var savedBufferSize = buf.length;
  for (var j = 0, n = message.countOf(field); j < n; j++) {
    var val = message.get(field, j);
    this.getSerializedValue(field, val, true /* omit tag */);
  }
  var serializedData = buf.splice(
      savedBufferSize, buf.length - savedBufferSize);
  this.serializeVarint_(serializedData.length);

  var args = [buf.length, 0].concat(serializedData);
  buf.splice.apply(buf, args);

  return true;
};


/**
 * Append the serialized field tag to our serialization buffer.
 * @param {goog.proto2.FieldDescriptor} field The field to serialize.
 * @return {boolean} Whether the field tag was serialized.
 * @private
 */
net.proto2.contrib.WireSerializer.prototype.serializeFieldTag_ =
    function(field) {
  var wireType = 0;
  switch (field.getFieldType()) {
    default:
      return false;
    case goog.proto2.Message.FieldType.SINT32:
    case goog.proto2.Message.FieldType.SINT64:
    case goog.proto2.Message.FieldType.BOOL:
    case goog.proto2.Message.FieldType.INT64:
    case goog.proto2.Message.FieldType.ENUM:
    case goog.proto2.Message.FieldType.INT32:
    case goog.proto2.Message.FieldType.UINT32:
    case goog.proto2.Message.FieldType.UINT64:
      wireType = 0;
      break;
    case goog.proto2.Message.FieldType.FIXED64:
    case goog.proto2.Message.FieldType.SFIXED64:
    case goog.proto2.Message.FieldType.DOUBLE:
      wireType = 1;
      break;
    case goog.proto2.Message.FieldType.STRING:
    case goog.proto2.Message.FieldType.BYTES:
    case goog.proto2.Message.FieldType.MESSAGE:
      wireType = 2;
      break;
    case goog.proto2.Message.FieldType.GROUP:
      wireType = 3;
      break;
    case goog.proto2.Message.FieldType.FIXED32:
    case goog.proto2.Message.FieldType.SFIXED32:
    case goog.proto2.Message.FieldType.FLOAT:
      wireType = 5;
      break;
  }
  this.serializeVarint_((field.getTag() << 3) | wireType);
  return true;
};


/**
 * Returns the serialized form of the given value for the given field if the
 * field is a Message or Group and returns the value unchanged otherwise, except
 * for Infinity, -Infinity and NaN numerical values which are converted to
 * string representation.
 *
 * @param {goog.proto2.FieldDescriptor} field The field from which this
 *     value came.
 * @param {*} value The value of the field.
 * @param {boolean=} opt_omitTag If present and true, do not serialize a field
 *     tag.
 *
 * @return {*} The value.
 * @protected
 */
net.proto2.contrib.WireSerializer.prototype.getSerializedValue =
    function(field, value, opt_omitTag) {
  if (!opt_omitTag) {
    if (!this.serializeFieldTag_(field)) {
      return false;
    }
  }

  switch (field.getFieldType()) {
    default:
      throw new Error('Unknown field type ' + field.getFieldType());
    case goog.proto2.Message.FieldType.SINT32:
      this.serializeVarint_(this.zigZagEncode(/** @type {number} */ (value)));
      break;
    case goog.proto2.Message.FieldType.SINT64:
      this.serializeVarint64_(this.zigZagEncode64_(
          goog.math.Long.fromString(/** @type {string} */(value))));
      break;
    case goog.proto2.Message.FieldType.BOOL:
      this.serializeVarint_(value ? 1 : 0);
      break;
    case goog.proto2.Message.FieldType.INT32:
      var numericValue = /** @type {number} */ (value);
      if (numericValue > 0) {
        this.serializeVarint_(numericValue);
      } else {
        // Negative 32 bit quantities are always 10 bytes long.
        this.serializeVarint64_(goog.math.Long.fromInt(numericValue));
      }
      break;
    case goog.proto2.Message.FieldType.INT64:
    case goog.proto2.Message.FieldType.UINT64:
      this.serializeVarint64_(
          goog.math.Long.fromString(/** @type {string} */(value)));
      break;
    case goog.proto2.Message.FieldType.ENUM:
    case goog.proto2.Message.FieldType.UINT32:
      this.serializeVarint_(/** @type {number} */ (value));
      break;
    case goog.proto2.Message.FieldType.FIXED64:
    case goog.proto2.Message.FieldType.SFIXED64:
      this.serializeFixed_(
          goog.math.Long.fromString(/** @type {string} */ (value)), 8);
      break;
    case goog.proto2.Message.FieldType.DOUBLE:
      this.serializeDouble_(/** @type {number} */ (value));
      break;
    case goog.proto2.Message.FieldType.STRING:
      this.serializeString(value);
      break;
    case goog.proto2.Message.FieldType.BYTES:
      this.serializeBytes(value);
      break;
    case goog.proto2.Message.FieldType.GROUP:
      var serialized = new net.proto2.contrib.WireSerializer().serialize(
          /** @type {goog.proto2.Message} */ (value));
      goog.array.extend(this.buffer_, serialized);
      this.serializeVarint_((field.getTag() << 3) | 4);
      break;
    case goog.proto2.Message.FieldType.MESSAGE:
      var serialized = new net.proto2.contrib.WireSerializer().serialize(
          /** @type {goog.proto2.Message} */ (value));
      this.serializeVarint_(serialized.length);
      goog.array.extend(this.buffer_, serialized);
      break;
    case goog.proto2.Message.FieldType.FIXED32:
      this.serializeFixed_(
          goog.math.Long.fromNumber(/** @type {number} */ (value)), 4);
      break;
    case goog.proto2.Message.FieldType.SFIXED32:
      this.serializeFixed_(
          goog.math.Long.fromInt(/** @type {number} */ (value)), 4);
      break;
    case goog.proto2.Message.FieldType.FLOAT:
      this.serializeFloat_(/** @type {number} */ (value));
      break;
  }
  // To avoid allocations, this method serializes into a pre-existing buffer,
  // rather than serializing into a new value object.
  return null;
};


/** @override */
net.proto2.contrib.WireSerializer.prototype.deserializeTo =
    function(message, buffer) {
  if (buffer == null) {
    // Since value double-equals null, it may be either null or undefined.
    // Ensure we return the same one, since they have different meanings.
    return buffer;
  }

  if (buffer instanceof ArrayBuffer) {
    buffer = new Uint8Array(buffer);
  }

  var descriptor = message.getDescriptor();
  var offset = 0;
  var size = buffer.length;
  var view = function() {
    return buffer.subarray(offset);
  };
  // Because subarray is broken on ie10, we can't simply advance our view of the
  // buffer. Instead, we keep track of an offset.
  while (offset < buffer.length) {
    var tag = this.parseUnsignedVarInt_(view());
    var tagValue = tag.value;
    var tagLength = tag.length;
    var index = tagValue >> 3;
    var wireType = tagValue & 0x7;  // Last 3 bits.

    // Advance.
    offset += tagLength;

    var field = descriptor.findFieldByTag(index);
    if (!field) {
      // Unknown field; skip it.
      offset += this.lengthForWireType_(wireType, view());
      continue;
    } else if (field.isPacked()) {  // Packed repeated.
      // Read byte length.
      var v = this.parseUnsignedVarInt_(view());
      var remaining = v.value;
      offset += v.length;
      while (remaining > 0 && offset < buffer.length) {
        var packedValue =
            this.getDeserializedValue(field, view());
        if (!packedValue) {
          throw new Error('Expected ' + field.getFieldType());
        }
        message.add(field, packedValue.value);
        offset += packedValue.length;
        remaining -= packedValue.length;
      }
    } else {
      var value = this.getDeserializedValue(field, view());
      if (!value) {
        throw new Error('Expected ' + field.getFieldType());
      }
      offset += value.length;
      if (field.isRepeated()) {
        message.add(field, value.value);
      } else {
        message.set(field, value.value);
      }
    }
  }
};


/**
 * @param {number} wireType
 * @param {*} buffer The data of the message.
 * @return {number} Default length to use for a given fieldType.
 * @private
 */
net.proto2.contrib.WireSerializer.prototype.lengthForWireType_ = function(
    wireType, buffer) {
  var length = 0;
  switch (wireType) {
    case 0:  // int32, int64, uint32, uint64, sint32, sint64, bool, enum.
      length = this.parseVarInt64_(buffer).length;
      break;
    case 1:  // fixed64, sfixed64, double.
      length = 8;
      break;
    case 2:  // Length-delimited: string, bytes, messages, repeated fields.
      var bufferLength = this.parseVarInt64_(buffer);
      length = bufferLength.length + bufferLength.value.toInt();
      break;
    case 3:  // "Start group". Not supported.
    case 4:  // "End group". Not supported.
      goog.asserts.fail('Error deserializing group');
      break;
    case 5:  // fixed32, sfixed32, float.
      length = 4;
      break;
  }
  return length;
};


/**
 * Deserializes a message from the expected format and places the
 * data in the message. The message must correspond to a group. Moreover
 * the buffer must be positioned after the initial START_GROUP tag for the
 * group. The message will be terminated by the first END_GROUP tag at the
 * same nesting level. It is the responsibility of the caller to validate that
 * its field index matches the one in the opening START_GROUP tag. Since groups
 * are not length-delimited, this method returns the length of the parsed
 * data excluding the END_GROUP tag.
 *
 * @param {goog.proto2.Message} message The message in which to
 *     place the information.
 * @param {*} buffer The data of the message.
 * @return {number} the length of the parsed message, excluding the closing tag.
 * @protected
 */
 net.proto2.contrib.WireSerializer.prototype.deserializeGroupTo =
    function(message, buffer) {
  var descriptor = message.getDescriptor();
  var parsedLength = 0;

  while (true) {
    var tag = this.parseUnsignedVarInt_(buffer);
    var tagValue = tag.value;
    var tagLength = tag.length;
    var index = tagValue >> 3;
    var wiretype = tagValue & 7;
    if (wiretype == 4) {
      // Got an end group.
      break;
    }
    parsedLength += tagLength;
    var value = {value: undefined, length: 0};
    var field = descriptor.findFieldByTag(index);
    if (field) {
      value = this.getDeserializedValue(field, buffer.subarray(tagLength));
      if (value && value.value !== null) {
        if (field.isRepeated()) {
          message.add(field, value.value);
        } else {
          message.set(field, value.value);
        }
      }
    }
    parsedLength += value.length;
    if (buffer.length < tagLength + value.length) {
      break;
    }
    buffer = buffer.subarray(tagLength + value.length);
  }
  return parsedLength;
};


/**
 * @override
 */
net.proto2.contrib.WireSerializer.prototype.getDeserializedValue =
    function(field, buffer) {
  var value = null;
  var t = field.getFieldType();
  var varInt = this.parseVarInt64_(buffer);
  var length = varInt.length;
  switch (t) {
    case goog.proto2.Message.FieldType.SINT32:
      value = this.zigZagDecode_(varInt.value.toInt());
      break;
    case goog.proto2.Message.FieldType.SINT64:
      value = this.zigZagDecode64_(varInt.value).toString();
      break;
    case goog.proto2.Message.FieldType.BOOL:
      value = varInt.value.equals(goog.math.Long.getOne());
      break;
    case goog.proto2.Message.FieldType.INT64:
    case goog.proto2.Message.FieldType.UINT64:
      value = varInt.value.toString();
      break;
    case goog.proto2.Message.FieldType.INT32:
      value = varInt.value.toInt();
      break;
    case goog.proto2.Message.FieldType.ENUM:
    case goog.proto2.Message.FieldType.UINT32:
      value = varInt.value.getLowBitsUnsigned();
      break;
    case goog.proto2.Message.FieldType.FIXED64:
    case goog.proto2.Message.FieldType.SFIXED64:
      value = this.parseFixed64_(buffer.subarray(0, 8)).toString();
      length = 8;
      break;
    case goog.proto2.Message.FieldType.DOUBLE:
      value = this.parseDouble_(buffer.subarray(0, 8));
      length = 8;
      break;
    case goog.proto2.Message.FieldType.STRING:
      var strBuffer =
          buffer.subarray(varInt.length, varInt.length + varInt.value.toInt());
      value = this.arrayBufferToUtf8String_(strBuffer);
      length = varInt.length + varInt.value.toInt();
      break;
    case goog.proto2.Message.FieldType.BYTES:
      var strBuffer =
          buffer.subarray(varInt.length, varInt.length + varInt.value.toInt());
      // Store the bytes using a String.
      value = this.arrayBufferToString_(strBuffer);
      length = varInt.length + varInt.value.toInt();
      break;
    case goog.proto2.Message.FieldType.GROUP:
      value = field.getFieldMessageType().createMessageInstance();
      var groupLength = this.deserializeGroupTo(value, buffer);
      var next = buffer.subarray(groupLength);
      var closingTag = this.parseVarInt64_(next);
      var expected = (field.getTag() << 3) | 4;
      goog.asserts.assert(closingTag.value.toInt() == expected,
          'Error deserializing group');
      length = groupLength + closingTag.length;
      break;
    case goog.proto2.Message.FieldType.MESSAGE:
      length = varInt.length + varInt.value.toInt();
      var data = buffer.subarray(varInt.length, length);
      value = field.getFieldMessageType().createMessageInstance();
      this.deserializeTo(value, data);
      break;
    case goog.proto2.Message.FieldType.FIXED32:
    case goog.proto2.Message.FieldType.SFIXED32:
      value = this.parseFixed32_(
          buffer.subarray(0, 4), t == goog.proto2.Message.FieldType.SFIXED32);
      length = 4;
      break;
    case goog.proto2.Message.FieldType.FLOAT:
      value = this.parseFloat_(buffer.subarray(0, 4));
      length = 4;
      break;
  }
  return {value: value, length: length};
};


/**
 * @param {*} value Binary string that needs to be converted to bytes.
 */
net.proto2.contrib.WireSerializer.prototype.serializeBytes = function(value) {
  if (goog.isDefAndNotNull(value)) {
    var valueStr = /** @type {string} */ (value);
    // Serialize the number of bytes, per spec of the wire format.
    this.serializeVarint_(valueStr.length);
    for (var i = 0; i < valueStr.length; i++) {
      this.buffer_.push(valueStr.charCodeAt(i));
    }
  }
};


/**
 * @param {*} value String (possibly utf-8) that needs to be converted to bytes.
 */
net.proto2.contrib.WireSerializer.prototype.serializeString = function(value) {
  if (goog.isDefAndNotNull(value)) {
    var valueStr = /** @type {string} */ (value);
    // Inspired by:
    // http://ecmanaut.blogspot.com/2006/07/encoding-decoding-utf8-in-javascript.html
    var utf8 = unescape(encodeURIComponent(valueStr));
    // Serialize the length of the encoded string: what we want is the number
    // of bytes, not the number of characters, per spec of the wire format.
    this.serializeVarint_(utf8.length);
    for (var i = 0; i < utf8.length; i++) {
      this.buffer_.push(utf8.charCodeAt(i));
    }
  }
};


/**
 * @param {*} buffer to parse as String.
 * @return {{value: string, length: number}}
 */
net.proto2.contrib.WireSerializer.prototype.parseString = function(buffer) {
  var length = this.parseUnsignedVarInt_(buffer);
  var strBuffer = buffer.subarray(length.length, length.length + length.value);
  return {
    value: this.arrayBufferToUtf8String_(strBuffer),
    length: length.length + length.value
  };
};


/**
 * @param {number} number signed number that needs to be converted to unsigned.
 * @return {number}
 */
net.proto2.contrib.WireSerializer.prototype.zigZagEncode =
    function(number) {
  var sign = number >>> 31;
  return (number << 1) ^ -sign;
};


/**
 * @param {number} number Unsigned number in zigzag format that needs
                   to be converted to signed.
 * @return {number} signed.
 * @private
 */
net.proto2.contrib.WireSerializer.prototype.zigZagDecode_ =
    function(number) {
  return (number >>> 1) ^ -(number & 1);
};


/**
 * @param {!goog.math.Long} number signed number that needs to be converted to
 * unsigned.
 * @return {!goog.math.Long}
 * @private
 */
net.proto2.contrib.WireSerializer.prototype.zigZagEncode64_ =
    function(number) {
  var sign = number.shiftRightUnsigned(63);
  return number.shiftLeft(1).xor(sign.negate());
};


/**
 * @param {!goog.math.Long} number Unsigned number in zigzag format that needs
                   to be converted to signed.
 * @return {!goog.math.Long}
 * @private
 */
net.proto2.contrib.WireSerializer.prototype.zigZagDecode64_ =
    function(number) {
  return number.shiftRightUnsigned(1).xor(
      number.and(goog.math.Long.getOne()).negate());
};


/**
 * Serialize the given number as a varint into our buffer.
 * @param {number} number that needs to be converted to varint.
 * @private
 */
net.proto2.contrib.WireSerializer.prototype.serializeVarint_ =
    function(number) {
  do {
    var chunk = number & 0x7F;
    number = number >>> 7;
    if (number > 0) {
      chunk = chunk | 0x80;
    }
    this.buffer_.push(chunk);
  } while (number > 0);
};


/**
 * Serialize the given 64-bit number as a varint into our buffer.
 * @param {!goog.math.Long} number that needs to be encoded as varint.
 * @private
 */
net.proto2.contrib.WireSerializer.prototype.serializeVarint64_ =
    function(number) {
  var mask = goog.math.Long.fromInt(0x7F);
  do {
    var chunk = number.and(mask).toInt();
    number = number.shiftRightUnsigned(7);
    if (number.greaterThan(goog.math.Long.getZero())) {
      chunk = chunk | 0x80;
    }
    this.buffer_.push(chunk);
  } while (number.greaterThan(goog.math.Long.getZero()));
};


/**
 * @param {*} buffer from which field number and type needs to be extracted.
 * @return {{value: !goog.math.Long, length: number}}
 * @private
 */
net.proto2.contrib.WireSerializer.prototype.parseVarInt64_ = function(buffer) {
  var valueInfo = this.scratchTag64_;
  var number = goog.math.Long.fromNumber(0);
  var i = 0;
  for (; i < buffer.length; i++) {
    var bits = goog.math.Long.fromInt(buffer[i] & 0x7F).shiftLeft(i * 7);
    number = number.or(bits);
    if ((buffer[i] & 0x80) == 0) {
      break;
    }
  }
  valueInfo.value = number;
  valueInfo.length = i + 1;
  return valueInfo;
};


/**
 * A special case parser for unsigned 32-bit varints, which can fit comfortably
 * in 32 bits during decoding.
 * @param {*} buffer from which field number and type needs to be extracted.
 * @return {{value: number, length: number}}
 * @private
 */
net.proto2.contrib.WireSerializer.prototype.parseUnsignedVarInt_ =
    function(buffer) {
  var valueInfo = this.scratchTag32_;
  var result = 0;
  var i = 0;
  for (; i < buffer.length; i++) {
    result = result | ((buffer[i] & 0x7F) << (i * 7));
    if ((buffer[i] & 0x80) == 0) {
      break;
    }
  }
  valueInfo.value = result;
  valueInfo.length = i + 1;
  return valueInfo;
};


/**
 * @param {goog.math.Long} number that needs to be converted to little endian
 *     order.
 * @param {number} size of the result array (4 = 32bit, 8 = 64bit).
 * @private
 */
net.proto2.contrib.WireSerializer.prototype.serializeFixed_ =
    function(number, size) {
  var mask = goog.math.Long.fromInt(0xFF);
  for (var i = 0; i < size; i++) {
    var chunk = number.and(mask).toInt();
    this.buffer_.push(chunk);
    number = number.shiftRightUnsigned(8);
  }
};


/**
 * @param {*} buffer from which the fixed32 value needs to be extracted.
 * @param {boolean} signed if the fixed32 value represents a signed value
 *     (i.e. sfixed32).
 * @return {number}
 * @private
 */
net.proto2.contrib.WireSerializer.prototype.parseFixed32_ = function(
    buffer, signed) {
  var number = 0;
  for (var i = 0; i < buffer.length; i++) {
    number = number | (buffer[i] << (i * 8));
  }
  if (!signed) {
    // The bitwise operations above treat numbers as signed int32 values.
    // Correct for this in the unsigned case by using >>> to coerce to unsigned.
    number = number >>> 0;
  }
  return number;
};


/**
 * @param {*} buffer from which the fixed64 value needs to be extracted.
 * @return {!goog.math.Long}
 * @private
 */
net.proto2.contrib.WireSerializer.prototype.parseFixed64_ = function(buffer) {
  // Javascript numbers are only accurate up to 51 bits as they are stored as
  // 64-bit floating points. We store the result in a goog.math.Long object to
  // preserve full precision.
  return new goog.math.Long(
      this.parseFixed32_(buffer.subarray(0, 4), true),
      this.parseFixed32_(buffer.subarray(4, 8), true));
};


/**
 * @param {*} buffer from which double needs to be extracted.
 * @return {number}
 * @private
 */
net.proto2.contrib.WireSerializer.prototype.parseDouble_ = function(buffer) {
  for (var i = 0; i < 8; i++) {
    this.dataView_.setUint8(i, buffer[i]);
  }
  return this.dataView_.getFloat64(0, true);  // little-endian
};


/**
 * @param {*} buffer from which float needs to be extracted.
 * @return {number}
 * @private
 */
net.proto2.contrib.WireSerializer.prototype.parseFloat_ = function(buffer) {
  for (var i = 0; i < 4; i++) {
    this.dataView_.setUint8(i, buffer[i]);
  }
  return this.dataView_.getFloat32(0, true);  // little-endian
};


/**
 * @param {number} number to be serialized to 8 bytes.
 * @private
 */
net.proto2.contrib.WireSerializer.prototype.serializeDouble_ =
    function(number) {
  this.dataView_.setFloat64(0, number, true);  // little-endian
  for (var i = 0; i < 8; i++) {
    this.buffer_.push(this.dataView_.getUint8(i));
  }
};


/**
 * @param {number} number to be serialized to 4 bytes.
 * @private
 */
net.proto2.contrib.WireSerializer.prototype.serializeFloat_ = function(number) {
  this.dataView_.setFloat32(0, number, true);  // little-endian
  for (var i = 0; i < 4; i++) {
    this.buffer_.push(this.dataView_.getUint8(i));
  }
};


/**
 * This method converts an ArrayBuffer into a string (with utf8 encoding).
 *
 * @param {ArrayBuffer} buffer The buffer to convert to a string
 * @return {string}
 * @private
 */
net.proto2.contrib.WireSerializer.prototype.arrayBufferToUtf8String_ = function(
    buffer) {
  var str = this.arrayBufferToString_(buffer);
  // Inspired by:
  // http://ecmanaut.blogspot.com/2006/07/encoding-decoding-utf8-in-javascript.html
  return decodeURIComponent(escape(str));
};


/**
 * This method converts an ArrayBuffer into a string (each index is 1 byte).
 *
 * The maximum stack size in chrome is ~125k.  This means that using
 * String.fromCharCode.apply will fail for strings larger than the maximum stack
 * size.  This method breaks up the calls to fromCharCode into ~64k chunks to
 * work around this limitation.
 *
 * @param {ArrayBuffer} buffer The buffer to convert to a string
 * @return {string}
 * @private
 */
net.proto2.contrib.WireSerializer.prototype.arrayBufferToString_ = function(
    buffer) {
  var CHUNK_SIZE = 65536;
  var str = '';
  var view = new Uint16Array(buffer);
  for (var offset = 0; offset < view.length; offset += CHUNK_SIZE) {
    var len = Math.min(CHUNK_SIZE, view.length - offset);
    var subview = view.subarray(offset, offset + len);
    str += String.fromCharCode.apply(null, subview);
  }
  return str;
};