// 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,
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// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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// 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);
};
