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Diffstat (limited to 'js/binary/decoder.js')
| -rw-r--r-- | js/binary/decoder.js | 1007 |
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diff --git a/js/binary/decoder.js b/js/binary/decoder.js deleted file mode 100644 index 41094a36..00000000 --- a/js/binary/decoder.js +++ /dev/null @@ -1,1007 +0,0 @@ -// 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('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>} */ - 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 ? 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. Those - // bits _must_ be zero, or the encoding is invalid. - goog.asserts.assert((temp & 0xF0) == 0); - this.cursor_ += 5; - goog.asserts.assert(this.cursor_ <= this.end_); - return x >>> 0; - } - - // If we get here, we're reading the sign extension of a negative 32-bit int. - // We can skip these bytes, as we know in advance that they have to be all - // 1's if the varint is correctly encoded. Since we also know the value is - // negative, we don't have to coerce it to unsigned before we return it. - - goog.asserts.assert((temp & 0xF0) == 0xF0); - goog.asserts.assert(bytes[this.cursor_ + 5] == 0xFF); - goog.asserts.assert(bytes[this.cursor_ + 6] == 0xFF); - goog.asserts.assert(bytes[this.cursor_ + 7] == 0xFF); - goog.asserts.assert(bytes[this.cursor_ + 8] == 0xFF); - goog.asserts.assert(bytes[this.cursor_ + 9] == 0x01); - - this.cursor_ += 10; - 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 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 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 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, with - * the exception that the implementation here does not get confused if it - * encounters characters longer than three bytes. These characters are ignored - * though, as they are extremely rare: three UTF-8 bytes cover virtually all - * characters in common use (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 chars = []; - - while (cursor < end) { - var c = bytes[cursor++]; - if (c < 128) { // Regular 7-bit ASCII. - chars.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 three bytes. - continue; - } else if (c < 224) { // UTF-8 with two bytes. - var c2 = bytes[cursor++]; - chars.push(((c & 31) << 6) | (c2 & 63)); - } else if (c < 240) { // UTF-8 with three bytes. - var c2 = bytes[cursor++]; - var c3 = bytes[cursor++]; - chars.push(((c & 15) << 12) | ((c2 & 63) << 6) | (c3 & 63)); - } - } - - // String.fromCharCode.apply is faster than manually appending characters on - // Chrome 25+, and generates no additional cons string garbage. - var result = String.fromCharCode.apply(null, chars); - 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); -}; |