text: // 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 This file contains utilities for decoding primitive values
   * (signed and unsigned integers, varints, booleans, enums, hashes, strings,
   * and raw bytes) embedded in Uint8Arrays into their corresponding Javascript
   * types.
   *
   * Major caveat - Javascript is unable to accurately represent integers larger
   * than 2^53 due to its use of a double-precision floating point format or all
   * numbers. If you need to guarantee that 64-bit values survive with all bits
   * intact, you _must_ read them using one of the Hash64 methods, which return
   * an 8-character string.
   *
   * @author aappleby@google.com (Austin Appleby)
   */
  
  goog.provide('jspb.BinaryDecoder');
  goog.provide('jspb.BinaryIterator');
  
  goog.require('goog.asserts');
  goog.require('goog.crypt');
  goog.require('jspb.utils');
  
  
  
  /**
   * Simple helper class for traversing the contents of repeated scalar fields.
   * that may or may not have been packed into a wire-format blob.
   * @param {?jspb.BinaryDecoder=} opt_decoder
   * @param {?function(this:jspb.BinaryDecoder):(number|boolean|string)=}
   *     opt_next The decoder method to use for next().
   * @param {?Array<number|boolean|string>=} opt_elements
   * @constructor
   * @struct
   */
  jspb.BinaryIterator = function(opt_decoder, opt_next, opt_elements) {
    /** @private {jspb.BinaryDecoder} */
    this.decoder_ = null;
  
    /**
     * The BinaryDecoder member function used when iterating over packed data.
     * @private {?function(this:jspb.BinaryDecoder):(number|boolean|string)}
     */
    this.nextMethod_ = null;
  
    /** @private {?Array<number|boolean|string>} */
    this.elements_ = null;
  
    /** @private {number} */
    this.cursor_ = 0;
  
    /** @private {number|boolean|string|null} */
    this.nextValue_ = null;
  
    /** @private {boolean} */
    this.atEnd_ = true;
  
    this.init_(opt_decoder, opt_next, opt_elements);
  };
  
  
  /**
   * @param {?jspb.BinaryDecoder=} opt_decoder
   * @param {?function(this:jspb.BinaryDecoder):(number|boolean|string)=}
   *     opt_next The decoder method to use for next().
   * @param {?Array<number|boolean|string>=} opt_elements
   * @private
   */
  jspb.BinaryIterator.prototype.init_ =
      function(opt_decoder, opt_next, opt_elements) {
    if (opt_decoder && opt_next) {
      this.decoder_ = opt_decoder;
      this.nextMethod_ = opt_next;
    }
    this.elements_ = opt_elements || null;
    this.cursor_ = 0;
    this.nextValue_ = null;
    this.atEnd_ = !this.decoder_ && !this.elements_;
  
    this.next();
  };
  
  
  /**
   * Global pool of BinaryIterator instances.
   * @private {!Array<!jspb.BinaryIterator>}
   */
  jspb.BinaryIterator.instanceCache_ = [];
  
  
  /**
   * Allocates a BinaryIterator from the cache, creating a new one if the cache
   * is empty.
   * @param {?jspb.BinaryDecoder=} opt_decoder
   * @param {?function(this:jspb.BinaryDecoder):(number|boolean|string)=}
   *     opt_next The decoder method to use for next().
   * @param {?Array<number|boolean|string>=} opt_elements
   * @return {!jspb.BinaryIterator}
   */
  jspb.BinaryIterator.alloc = function(opt_decoder, opt_next, opt_elements) {
    if (jspb.BinaryIterator.instanceCache_.length) {
      var iterator = jspb.BinaryIterator.instanceCache_.pop();
      iterator.init_(opt_decoder, opt_next, opt_elements);
      return iterator;
    } else {
      return new jspb.BinaryIterator(opt_decoder, opt_next, opt_elements);
    }
  };
  
  
  /**
   * Puts this instance back in the instance cache.
   */
  jspb.BinaryIterator.prototype.free = function() {
    this.clear();
    if (jspb.BinaryIterator.instanceCache_.length < 100) {
      jspb.BinaryIterator.instanceCache_.push(this);
    }
  };
  
  
  /**
   * Clears the iterator.
   */
  jspb.BinaryIterator.prototype.clear = function() {
    if (this.decoder_) {
      this.decoder_.free();
    }
    this.decoder_ = null;
    this.nextMethod_ = null;
    this.elements_ = null;
    this.cursor_ = 0;
    this.nextValue_ = null;
    this.atEnd_ = true;
  };
  
  
  /**
   * Returns the element at the iterator, or null if the iterator is invalid or
   * past the end of the decoder/array.
   * @return {number|boolean|string|null}
   */
  jspb.BinaryIterator.prototype.get = function() {
    return this.nextValue_;
  };
  
  
  /**
   * Returns true if the iterator is at the end of the decoder/array.
   * @return {boolean}
   */
  jspb.BinaryIterator.prototype.atEnd = function() {
    return this.atEnd_;
  };
  
  
  /**
   * Returns the element at the iterator and steps to the next element,
   * equivalent to '*pointer++' in C.
   * @return {number|boolean|string|null}
   */
  jspb.BinaryIterator.prototype.next = function() {
    var lastValue = this.nextValue_;
    if (this.decoder_) {
      if (this.decoder_.atEnd()) {
        this.nextValue_ = null;
        this.atEnd_ = true;
      } else {
        this.nextValue_ = this.nextMethod_.call(this.decoder_);
      }
    } else if (this.elements_) {
      if (this.cursor_ == this.elements_.length) {
        this.nextValue_ = null;
        this.atEnd_ = true;
      } else {
        this.nextValue_ = this.elements_[this.cursor_++];
      }
    }
    return lastValue;
  };
  
  
  
  /**
   * BinaryDecoder implements the decoders for all the wire types specified in
   * https://developers.google.com/protocol-buffers/docs/encoding.
   *
   * @param {jspb.ByteSource=} opt_bytes The bytes we're reading from.
   * @param {number=} opt_start The optional offset to start reading at.
   * @param {number=} opt_length The optional length of the block to read -
   *     we'll throw an assertion if we go off the end of the block.
   * @constructor
   * @struct
   */
  jspb.BinaryDecoder = function(opt_bytes, opt_start, opt_length) {
    /**
     * Typed byte-wise view of the source buffer.
     * @private {?Uint8Array}
     */
    this.bytes_ = null;
  
    /**
     * Start point of the block to read.
     * @private {number}
     */
    this.start_ = 0;
  
    /**
     * End point of the block to read.
     * @private {number}
     */
    this.end_ = 0;
  
    /**
     * Current read location in bytes_.
     * @private {number}
     */
    this.cursor_ = 0;
  
    /**
     * Temporary storage for the low 32 bits of 64-bit data types that we're
     * decoding.
     * @private {number}
     */
    this.tempLow_ = 0;
  
    /**
     * Temporary storage for the high 32 bits of 64-bit data types that we're
     * decoding.
     * @private {number}
     */
    this.tempHigh_ = 0;
  
    /**
     * Set to true if this decoder encountered an error due to corrupt data.
     * @private {boolean}
     */
    this.error_ = false;
  
    if (opt_bytes) {
      this.setBlock(opt_bytes, opt_start, opt_length);
    }
  };
  
  
  /**
   * Global pool of BinaryDecoder instances.
   * @private {!Array<!jspb.BinaryDecoder>}
   */
  jspb.BinaryDecoder.instanceCache_ = [];
  
  
  /**
   * Pops an instance off the instance cache, or creates one if the cache is
   * empty.
   * @param {jspb.ByteSource=} opt_bytes The bytes we're reading from.
   * @param {number=} opt_start The optional offset to start reading at.
   * @param {number=} opt_length The optional length of the block to read -
   *     we'll throw an assertion if we go off the end of the block.
   * @return {!jspb.BinaryDecoder}
   */
  jspb.BinaryDecoder.alloc = function(opt_bytes, opt_start, opt_length) {
    if (jspb.BinaryDecoder.instanceCache_.length) {
      var newDecoder = jspb.BinaryDecoder.instanceCache_.pop();
      if (opt_bytes) {
        newDecoder.setBlock(opt_bytes, opt_start, opt_length);
      }
      return newDecoder;
    } else {
      return new jspb.BinaryDecoder(opt_bytes, opt_start, opt_length);
    }
  };
  
  
  /**
   * Puts this instance back in the instance cache.
   */
  jspb.BinaryDecoder.prototype.free = function() {
    this.clear();
    if (jspb.BinaryDecoder.instanceCache_.length < 100) {
      jspb.BinaryDecoder.instanceCache_.push(this);
    }
  };
  
  
  /**
   * Makes a copy of this decoder.
   * @return {!jspb.BinaryDecoder}
   */
  jspb.BinaryDecoder.prototype.clone = function() {
    return jspb.BinaryDecoder.alloc(this.bytes_,
        this.start_, this.end_ - this.start_);
  };
  
  
  /**
   * Clears the decoder.
   */
  jspb.BinaryDecoder.prototype.clear = function() {
    this.bytes_ = null;
    this.start_ = 0;
    this.end_ = 0;
    this.cursor_ = 0;
    this.error_ = false;
  };
  
  
  /**
   * Returns the raw buffer.
   * @return {?Uint8Array} The raw buffer.
   */
  jspb.BinaryDecoder.prototype.getBuffer = function() {
    return this.bytes_;
  };
  
  
  /**
   * Changes the block of bytes we're decoding.
   * @param {!jspb.ByteSource} data The bytes we're reading from.
   * @param {number=} opt_start The optional offset to start reading at.
   * @param {number=} opt_length The optional length of the block to read -
   *     we'll throw an assertion if we go off the end of the block.
   */
  jspb.BinaryDecoder.prototype.setBlock =
      function(data, opt_start, opt_length) {
    this.bytes_ = jspb.utils.byteSourceToUint8Array(data);
    this.start_ = goog.isDef(opt_start) ? opt_start : 0;
    this.end_ =
        goog.isDef(opt_length) ? this.start_ + opt_length : this.bytes_.length;
    this.cursor_ = this.start_;
  };
  
  
  /**
   * @return {number}
   */
  jspb.BinaryDecoder.prototype.getEnd = function() {
    return this.end_;
  };
  
  
  /**
   * @param {number} end
   */
  jspb.BinaryDecoder.prototype.setEnd = function(end) {
    this.end_ = end;
  };
  
  
  /**
   * Moves the read cursor back to the start of the block.
   */
  jspb.BinaryDecoder.prototype.reset = function() {
    this.cursor_ = this.start_;
  };
  
  
  /**
   * Returns the internal read cursor.
   * @return {number} The internal read cursor.
   */
  jspb.BinaryDecoder.prototype.getCursor = function() {
    return this.cursor_;
  };
  
  
  /**
   * Returns the internal read cursor.
   * @param {number} cursor The new cursor.
   */
  jspb.BinaryDecoder.prototype.setCursor = function(cursor) {
    this.cursor_ = cursor;
  };
  
  
  /**
   * Advances the stream cursor by the given number of bytes.
   * @param {number} count The number of bytes to advance by.
   */
  jspb.BinaryDecoder.prototype.advance = function(count) {
    this.cursor_ += count;
    goog.asserts.assert(this.cursor_ <= this.end_);
  };
  
  
  /**
   * Returns true if this decoder is at the end of the block.
   * @return {boolean}
   */
  jspb.BinaryDecoder.prototype.atEnd = function() {
    return this.cursor_ == this.end_;
  };
  
  
  /**
   * Returns true if this decoder is at the end of the block.
   * @return {boolean}
   */
  jspb.BinaryDecoder.prototype.pastEnd = function() {
    return this.cursor_ > this.end_;
  };
  
  
  /**
   * Returns true if this decoder encountered an error due to corrupt data.
   * @return {boolean}
   */
  jspb.BinaryDecoder.prototype.getError = function() {
    return this.error_ ||
           (this.cursor_ < 0) ||
           (this.cursor_ > this.end_);
  };
  
  
  /**
   * Reads an unsigned varint from the binary stream and stores it as a split
   * 64-bit integer. Since this does not convert the value to a number, no
   * precision is lost.
   *
   * It's possible for an unsigned varint to be incorrectly encoded - more than
   * 64 bits' worth of data could be present. If this happens, this method will
   * throw an error.
   *
   * Decoding varints requires doing some funny base-128 math - for more
   * details on the format, see
   * https://developers.google.com/protocol-buffers/docs/encoding
   *
   * @private
   */
  jspb.BinaryDecoder.prototype.readSplitVarint64_ = function() {
    var temp;
    var lowBits = 0;
    var highBits = 0;
  
    // Read the first four bytes of the varint, stopping at the terminator if we
    // see it.
    for (var i = 0; i < 4; i++) {
      temp = this.bytes_[this.cursor_++];
      lowBits |= (temp & 0x7F) << (i * 7);
      if (temp < 128) {
        this.tempLow_ = lowBits >>> 0;
        this.tempHigh_ = 0;
        return;
      }
    }
  
    // Read the fifth byte, which straddles the low and high dwords.
    temp = this.bytes_[this.cursor_++];
    lowBits |= (temp & 0x7F) << 28;
    highBits |= (temp & 0x7F) >> 4;
    if (temp < 128) {
      this.tempLow_ = lowBits >>> 0;
      this.tempHigh_ = highBits >>> 0;
      return;
    }
  
    // Read the sixth through tenth byte.
    for (var i = 0; i < 5; i++) {
      temp = this.bytes_[this.cursor_++];
      highBits |= (temp & 0x7F) << (i * 7 + 3);
      if (temp < 128) {
        this.tempLow_ = lowBits >>> 0;
        this.tempHigh_ = highBits >>> 0;
        return;
      }
    }
  
    // If we did not see the terminator, the encoding was invalid.
    goog.asserts.fail('Failed to read varint, encoding is invalid.');
    this.error_ = true;
  };
  
  
  /**
   * Skips over a varint in the block without decoding it.
   */
  jspb.BinaryDecoder.prototype.skipVarint = function() {
    while (this.bytes_[this.cursor_] & 0x80) {
      this.cursor_++;
    }
    this.cursor_++;
  };
  
  
  /**
   * Skips backwards over a varint in the block - to do this correctly, we have
   * to know the value we're skipping backwards over or things are ambiguous.
   * @param {number} value The varint value to unskip.
   */
  jspb.BinaryDecoder.prototype.unskipVarint = function(value) {
    while (value > 128) {
      this.cursor_--;
      value = value >>> 7;
    }
    this.cursor_--;
  };
  
  
  /**
   * Reads a 32-bit varint from the binary stream. Due to a quirk of the encoding
   * format and Javascript's handling of bitwise math, this actually works
   * correctly for both signed and unsigned 32-bit varints.
   *
   * This function is called vastly more frequently than any other in
   * BinaryDecoder, so it has been unrolled and tweaked for performance.
   *
   * If there are more than 32 bits of data in the varint, it _must_ be due to
   * sign-extension. If we're in debug mode and the high 32 bits don't match the
   * expected sign extension, this method will throw an error.
   *
   * Decoding varints requires doing some funny base-128 math - for more
   * details on the format, see
   * https://developers.google.com/protocol-buffers/docs/encoding
   *
   * @return {number} The decoded unsigned 32-bit varint.
   */
  jspb.BinaryDecoder.prototype.readUnsignedVarint32 = function() {
    var temp;
    var bytes = this.bytes_;
  
    temp = bytes[this.cursor_ + 0];
    var x = (temp & 0x7F);
    if (temp < 128) {
      this.cursor_ += 1;
      goog.asserts.assert(this.cursor_ <= this.end_);
      return x;
    }
  
    temp = bytes[this.cursor_ + 1];
    x |= (temp & 0x7F) << 7;
    if (temp < 128) {
      this.cursor_ += 2;
      goog.asserts.assert(this.cursor_ <= this.end_);
      return x;
    }
  
    temp = bytes[this.cursor_ + 2];
    x |= (temp & 0x7F) << 14;
    if (temp < 128) {
      this.cursor_ += 3;
      goog.asserts.assert(this.cursor_ <= this.end_);
      return x;
    }
  
    temp = bytes[this.cursor_ + 3];
    x |= (temp & 0x7F) << 21;
    if (temp < 128) {
      this.cursor_ += 4;
      goog.asserts.assert(this.cursor_ <= this.end_);
      return x;
    }
  
    temp = bytes[this.cursor_ + 4];
    x |= (temp & 0x0F) << 28;
    if (temp < 128) {
      // We're reading the high bits of an unsigned varint. The byte we just read
      // also contains bits 33 through 35, which we're going to discard.
      this.cursor_ += 5;
      goog.asserts.assert(this.cursor_ <= this.end_);
      return x >>> 0;
    }
  
    // If we get here, we need to truncate coming bytes. However we need to make
    // sure cursor place is correct.
    this.cursor_ += 5;
    if (bytes[this.cursor_++] >= 128 &&
        bytes[this.cursor_++] >= 128 &&
        bytes[this.cursor_++] >= 128 &&
        bytes[this.cursor_++] >= 128 &&
        bytes[this.cursor_++] >= 128) {
      // If we get here, the varint is too long.
      goog.asserts.assert(false);
    }
  
    goog.asserts.assert(this.cursor_ <= this.end_);
    return x;
  };
  
  
  /**
   * The readUnsignedVarint32 above deals with signed 32-bit varints correctly,
   * so this is just an alias.
   *
   * @return {number} The decoded signed 32-bit varint.
   */
  jspb.BinaryDecoder.prototype.readSignedVarint32 =
      jspb.BinaryDecoder.prototype.readUnsignedVarint32;
  
  
  /**
   * Reads a 32-bit unsigned variant and returns its value as a string.
   *
   * @return {string} The decoded unsigned 32-bit varint as a string.
   */
  jspb.BinaryDecoder.prototype.readUnsignedVarint32String = function() {
    // 32-bit integers fit in JavaScript numbers without loss of precision, so
    // string variants of 32-bit varint readers can simply delegate then convert
    // to string.
    var value = this.readUnsignedVarint32();
    return value.toString();
  };
  
  
  /**
   * Reads a 32-bit signed variant and returns its value as a string.
   *
   * @return {string} The decoded signed 32-bit varint as a string.
   */
  jspb.BinaryDecoder.prototype.readSignedVarint32String = function() {
    // 32-bit integers fit in JavaScript numbers without loss of precision, so
    // string variants of 32-bit varint readers can simply delegate then convert
    // to string.
    var value = this.readSignedVarint32();
    return value.toString();
  };
  
  
  /**
   * Reads a signed, zigzag-encoded 32-bit varint from the binary stream.
   *
   * Zigzag encoding is a modification of varint encoding that reduces the
   * storage overhead for small negative integers - for more details on the
   * format, see https://developers.google.com/protocol-buffers/docs/encoding
   *
   * @return {number} The decoded signed, zigzag-encoded 32-bit varint.
   */
  jspb.BinaryDecoder.prototype.readZigzagVarint32 = function() {
    var result = this.readUnsignedVarint32();
    return (result >>> 1) ^ - (result & 1);
  };
  
  
  /**
   * Reads an unsigned 64-bit varint from the binary stream. Note that since
   * Javascript represents all numbers as double-precision floats, there will be
   * precision lost if the absolute value of the varint is larger than 2^53.
   *
   * @return {number} The decoded unsigned varint. Precision will be lost if the
   *     integer exceeds 2^53.
   */
  jspb.BinaryDecoder.prototype.readUnsignedVarint64 = function() {
    this.readSplitVarint64_();
    return jspb.utils.joinUint64(this.tempLow_, this.tempHigh_);
  };
  
  
  /**
   * Reads an unsigned 64-bit varint from the binary stream and returns the value
   * as a decimal string.
   *
   * @return {string} The decoded unsigned varint as a decimal string.
   */
  jspb.BinaryDecoder.prototype.readUnsignedVarint64String = function() {
    this.readSplitVarint64_();
    return jspb.utils.joinUnsignedDecimalString(this.tempLow_, this.tempHigh_);
  };
  
  
  /**
   * Reads a signed 64-bit varint from the binary stream. Note that since
   * Javascript represents all numbers as double-precision floats, there will be
   * precision lost if the absolute value of the varint is larger than 2^53.
   *
   * @return {number} The decoded signed varint. Precision will be lost if the
   *     integer exceeds 2^53.
   */
  jspb.BinaryDecoder.prototype.readSignedVarint64 = function() {
    this.readSplitVarint64_();
    return jspb.utils.joinInt64(this.tempLow_, this.tempHigh_);
  };
  
  
  /**
   * Reads an signed 64-bit varint from the binary stream and returns the value
   * as a decimal string.
   *
   * @return {string} The decoded signed varint as a decimal string.
   */
  jspb.BinaryDecoder.prototype.readSignedVarint64String = function() {
    this.readSplitVarint64_();
    return jspb.utils.joinSignedDecimalString(this.tempLow_, this.tempHigh_);
  };
  
  
  /**
   * Reads a signed, zigzag-encoded 64-bit varint from the binary stream. Note
   * that since Javascript represents all numbers as double-precision floats,
   * there will be precision lost if the absolute value of the varint is larger
   * than 2^53.
   *
   * Zigzag encoding is a modification of varint encoding that reduces the
   * storage overhead for small negative integers - for more details on the
   * format, see https://developers.google.com/protocol-buffers/docs/encoding
   *
   * @return {number} The decoded zigzag varint. Precision will be lost if the
   *     integer exceeds 2^53.
   */
  jspb.BinaryDecoder.prototype.readZigzagVarint64 = function() {
    this.readSplitVarint64_();
    return jspb.utils.joinZigzag64(this.tempLow_, this.tempHigh_);
  };
  
  
  /**
   * Reads a signed, zigzag-encoded 64-bit varint from the binary stream and
   * returns its valud as a string.
   *
   * Zigzag encoding is a modification of varint encoding that reduces the
   * storage overhead for small negative integers - for more details on the
   * format, see https://developers.google.com/protocol-buffers/docs/encoding
   *
   * @return {string} The decoded signed, zigzag-encoded 64-bit varint as a
   * string.
   */
  jspb.BinaryDecoder.prototype.readZigzagVarint64String = function() {
    // TODO(haberman): write lossless 64-bit zig-zag math.
    var value = this.readZigzagVarint64();
    return value.toString();
  };
  
  
  /**
   * Reads a raw unsigned 8-bit integer from the binary stream.
   *
   * @return {number} The unsigned 8-bit integer read from the binary stream.
   */
  jspb.BinaryDecoder.prototype.readUint8 = function() {
    var a = this.bytes_[this.cursor_ + 0];
    this.cursor_ += 1;
    goog.asserts.assert(this.cursor_ <= this.end_);
    return a;
  };
  
  
  /**
   * Reads a raw unsigned 16-bit integer from the binary stream.
   *
   * @return {number} The unsigned 16-bit integer read from the binary stream.
   */
  jspb.BinaryDecoder.prototype.readUint16 = function() {
    var a = this.bytes_[this.cursor_ + 0];
    var b = this.bytes_[this.cursor_ + 1];
    this.cursor_ += 2;
    goog.asserts.assert(this.cursor_ <= this.end_);
    return (a << 0) | (b << 8);
  };
  
  
  /**
   * Reads a raw unsigned 32-bit integer from the binary stream.
   *
   * @return {number} The unsigned 32-bit integer read from the binary stream.
   */
  jspb.BinaryDecoder.prototype.readUint32 = function() {
    var a = this.bytes_[this.cursor_ + 0];
    var b = this.bytes_[this.cursor_ + 1];
    var c = this.bytes_[this.cursor_ + 2];
    var d = this.bytes_[this.cursor_ + 3];
    this.cursor_ += 4;
    goog.asserts.assert(this.cursor_ <= this.end_);
    return ((a << 0) | (b << 8) | (c << 16) | (d << 24)) >>> 0;
  };
  
  
  /**
   * Reads a raw unsigned 64-bit integer from the binary stream. Note that since
   * Javascript represents all numbers as double-precision floats, there will be
   * precision lost if the absolute value of the integer is larger than 2^53.
   *
   * @return {number} The unsigned 64-bit integer read from the binary stream.
   *     Precision will be lost if the integer exceeds 2^53.
   */
  jspb.BinaryDecoder.prototype.readUint64 = function() {
    var bitsLow = this.readUint32();
    var bitsHigh = this.readUint32();
    return jspb.utils.joinUint64(bitsLow, bitsHigh);
  };
  
  
  /**
   * Reads a raw unsigned 64-bit integer from the binary stream. Note that since
   * Javascript represents all numbers as double-precision floats, there will be
   * precision lost if the absolute value of the integer is larger than 2^53.
   *
   * @return {string} The unsigned 64-bit integer read from the binary stream.
   */
  jspb.BinaryDecoder.prototype.readUint64String = function() {
    var bitsLow = this.readUint32();
    var bitsHigh = this.readUint32();
    return jspb.utils.joinUnsignedDecimalString(bitsLow, bitsHigh);
  };
  
  
  /**
   * Reads a raw signed 8-bit integer from the binary stream.
   *
   * @return {number} The signed 8-bit integer read from the binary stream.
   */
  jspb.BinaryDecoder.prototype.readInt8 = function() {
    var a = this.bytes_[this.cursor_ + 0];
    this.cursor_ += 1;
    goog.asserts.assert(this.cursor_ <= this.end_);
    return (a << 24) >> 24;
  };
  
  
  /**
   * Reads a raw signed 16-bit integer from the binary stream.
   *
   * @return {number} The signed 16-bit integer read from the binary stream.
   */
  jspb.BinaryDecoder.prototype.readInt16 = function() {
    var a = this.bytes_[this.cursor_ + 0];
    var b = this.bytes_[this.cursor_ + 1];
    this.cursor_ += 2;
    goog.asserts.assert(this.cursor_ <= this.end_);
    return (((a << 0) | (b << 8)) << 16) >> 16;
  };
  
  
  /**
   * Reads a raw signed 32-bit integer from the binary stream.
   *
   * @return {number} The signed 32-bit integer read from the binary stream.
   */
  jspb.BinaryDecoder.prototype.readInt32 = function() {
    var a = this.bytes_[this.cursor_ + 0];
    var b = this.bytes_[this.cursor_ + 1];
    var c = this.bytes_[this.cursor_ + 2];
    var d = this.bytes_[this.cursor_ + 3];
    this.cursor_ += 4;
    goog.asserts.assert(this.cursor_ <= this.end_);
    return (a << 0) | (b << 8) | (c << 16) | (d << 24);
  };
  
  
  /**
   * Reads a raw signed 64-bit integer from the binary stream. Note that since
   * Javascript represents all numbers as double-precision floats, there will be
   * precision lost if the absolute vlaue of the integer is larger than 2^53.
   *
   * @return {number} The signed 64-bit integer read from the binary stream.
   *     Precision will be lost if the integer exceeds 2^53.
   */
  jspb.BinaryDecoder.prototype.readInt64 = function() {
    var bitsLow = this.readUint32();
    var bitsHigh = this.readUint32();
    return jspb.utils.joinInt64(bitsLow, bitsHigh);
  };
  
  
  /**
   * Reads a raw signed 64-bit integer from the binary stream and returns it as a
   * string.
   *
   * @return {string} The signed 64-bit integer read from the binary stream.
   *     Precision will be lost if the integer exceeds 2^53.
   */
  jspb.BinaryDecoder.prototype.readInt64String = function() {
    var bitsLow = this.readUint32();
    var bitsHigh = this.readUint32();
    return jspb.utils.joinSignedDecimalString(bitsLow, bitsHigh);
  };
  
  
  /**
   * Reads a 32-bit floating-point number from the binary stream, using the
   * temporary buffer to realign the data.
   *
   * @return {number} The float read from the binary stream.
   */
  jspb.BinaryDecoder.prototype.readFloat = function() {
    var bitsLow = this.readUint32();
    var bitsHigh = 0;
    return jspb.utils.joinFloat32(bitsLow, bitsHigh);
  };
  
  
  /**
   * Reads a 64-bit floating-point number from the binary stream, using the
   * temporary buffer to realign the data.
   *
   * @return {number} The double read from the binary stream.
   */
  jspb.BinaryDecoder.prototype.readDouble = function() {
    var bitsLow = this.readUint32();
    var bitsHigh = this.readUint32();
    return jspb.utils.joinFloat64(bitsLow, bitsHigh);
  };
  
  
  /**
   * Reads a boolean value from the binary stream.
   * @return {boolean} The boolean read from the binary stream.
   */
  jspb.BinaryDecoder.prototype.readBool = function() {
    return !!this.bytes_[this.cursor_++];
  };
  
  
  /**
   * Reads an enum value from the binary stream, which are always encoded as
   * signed varints.
   * @return {number} The enum value read from the binary stream.
   */
  jspb.BinaryDecoder.prototype.readEnum = function() {
    return this.readSignedVarint32();
  };
  
  
  /**
   * Reads and parses a UTF-8 encoded unicode string from the stream.
   * The code is inspired by maps.vectortown.parse.StreamedDataViewReader.
   * Supports codepoints from U+0000 up to U+10FFFF.
   * (http://en.wikipedia.org/wiki/UTF-8).
   * @param {number} length The length of the string to read.
   * @return {string} The decoded string.
   */
  jspb.BinaryDecoder.prototype.readString = function(length) {
    var bytes = this.bytes_;
    var cursor = this.cursor_;
    var end = cursor + length;
    var codeUnits = [];
  
    var result = '';
    while (cursor < end) {
      var c = bytes[cursor++];
      if (c < 128) { // Regular 7-bit ASCII.
        codeUnits.push(c);
      } else if (c < 192) {
        // UTF-8 continuation mark. We are out of sync. This
        // might happen if we attempted to read a character
        // with more than four bytes.
        continue;
      } else if (c < 224) { // UTF-8 with two bytes.
        var c2 = bytes[cursor++];
        codeUnits.push(((c & 31) << 6) | (c2 & 63));
      } else if (c < 240) { // UTF-8 with three bytes.
        var c2 = bytes[cursor++];
        var c3 = bytes[cursor++];
        codeUnits.push(((c & 15) << 12) | ((c2 & 63) << 6) | (c3 & 63));
      } else if (c < 248) { // UTF-8 with 4 bytes.
        var c2 = bytes[cursor++];
        var c3 = bytes[cursor++];
        var c4 = bytes[cursor++];
        // Characters written on 4 bytes have 21 bits for a codepoint.
        // We can't fit that on 16bit characters, so we use surrogates.
        var codepoint = ((c & 7) << 18) | ((c2 & 63) << 12) | ((c3 & 63) << 6) | (c4 & 63);
        // Surrogates formula from wikipedia.
        // 1. Subtract 0x10000 from codepoint
        codepoint -= 0x10000;
        // 2. Split this into the high 10-bit value and the low 10-bit value
        // 3. Add 0xD800 to the high value to form the high surrogate
        // 4. Add 0xDC00 to the low value to form the low surrogate:
        var low = (codepoint & 1023) + 0xDC00;
        var high = ((codepoint >> 10) & 1023) + 0xD800;
        codeUnits.push(high, low);
      }
  
      // Avoid exceeding the maximum stack size when calling `apply`.
      if (codeUnits.length >= 8192) {
        result += String.fromCharCode.apply(null, codeUnits);
        codeUnits.length = 0;
      }
    }
    result += goog.crypt.byteArrayToString(codeUnits);
    this.cursor_ = cursor;
    return result;
  };
  
  
  /**
   * Reads and parses a UTF-8 encoded unicode string (with length prefix) from
   * the stream.
   * @return {string} The decoded string.
   */
  jspb.BinaryDecoder.prototype.readStringWithLength = function() {
    var length = this.readUnsignedVarint32();
    return this.readString(length);
  };
  
  
  /**
   * Reads a block of raw bytes from the binary stream.
   *
   * @param {number} length The number of bytes to read.
   * @return {!Uint8Array} The decoded block of bytes, or an empty block if the
   *     length was invalid.
   */
  jspb.BinaryDecoder.prototype.readBytes = function(length) {
    if (length < 0 ||
        this.cursor_ + length > this.bytes_.length) {
      this.error_ = true;
      goog.asserts.fail('Invalid byte length!');
      return new Uint8Array(0);
    }
  
    var result = this.bytes_.subarray(this.cursor_, this.cursor_ + length);
  
    this.cursor_ += length;
    goog.asserts.assert(this.cursor_ <= this.end_);
    return result;
  };
  
  
  /**
   * Reads a 64-bit varint from the stream and returns it as an 8-character
   * Unicode string for use as a hash table key.
   *
   * @return {string} The hash value.
   */
  jspb.BinaryDecoder.prototype.readVarintHash64 = function() {
    this.readSplitVarint64_();
    return jspb.utils.joinHash64(this.tempLow_, this.tempHigh_);
  };
  
  
  /**
   * Reads a 64-bit fixed-width value from the stream and returns it as an
   * 8-character Unicode string for use as a hash table key.
   *
   * @return {string} The hash value.
   */
  jspb.BinaryDecoder.prototype.readFixedHash64 = function() {
    var bytes = this.bytes_;
    var cursor = this.cursor_;
  
    var a = bytes[cursor + 0];
    var b = bytes[cursor + 1];
    var c = bytes[cursor + 2];
    var d = bytes[cursor + 3];
    var e = bytes[cursor + 4];
    var f = bytes[cursor + 5];
    var g = bytes[cursor + 6];
    var h = bytes[cursor + 7];
  
    this.cursor_ += 8;
  
    return String.fromCharCode(a, b, c, d, e, f, g, h);
  };
  