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Diffstat (limited to 'js/binary/encoder.js')
-rw-r--r-- | js/binary/encoder.js | 430 |
1 files changed, 430 insertions, 0 deletions
diff --git a/js/binary/encoder.js b/js/binary/encoder.js new file mode 100644 index 00000000..c9b0c2ae --- /dev/null +++ b/js/binary/encoder.js @@ -0,0 +1,430 @@ +// Protocol Buffers - Google's data interchange format +// Copyright 2008 Google Inc. All rights reserved. +// https://developers.google.com/protocol-buffers/ +// +// Redistribution and use in source and binary forms, with or without +// modification, are permitted provided that the following conditions are +// met: +// +// * Redistributions of source code must retain the above copyright +// notice, this list of conditions and the following disclaimer. +// * Redistributions in binary form must reproduce the above +// copyright notice, this list of conditions and the following disclaimer +// in the documentation and/or other materials provided with the +// distribution. +// * Neither the name of Google Inc. nor the names of its +// contributors may be used to endorse or promote products derived from +// this software without specific prior written permission. +// +// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS +// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT +// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR +// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT +// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, +// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT +// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, +// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY +// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT +// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE +// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + +/** + * @fileoverview BinaryEncode defines methods for encoding Javascript values + * into arrays of bytes compatible with the Protocol Buffer wire format. + * + * @author aappleby@google.com (Austin Appleby) + */ + +goog.provide('jspb.BinaryEncoder'); + +goog.require('goog.asserts'); +goog.require('jspb.BinaryConstants'); +goog.require('jspb.utils'); + + + +/** + * BinaryEncoder implements encoders for all the wire types specified in + * https://developers.google.com/protocol-buffers/docs/encoding. + * + * @constructor + * @struct + */ +jspb.BinaryEncoder = function() { + /** @private {!Array.<number>} */ + this.buffer_ = []; +}; + + +/** + * @return {number} + */ +jspb.BinaryEncoder.prototype.length = function() { + return this.buffer_.length; +}; + + +/** + * @return {!Array.<number>} + */ +jspb.BinaryEncoder.prototype.end = function() { + var buffer = this.buffer_; + this.buffer_ = []; + return buffer; +}; + + +/** + * Encodes a 64-bit integer in 32:32 split representation into its wire-format + * varint representation and stores it in the buffer. + * @param {number} lowBits The low 32 bits of the int. + * @param {number} highBits The high 32 bits of the int. + */ +jspb.BinaryEncoder.prototype.writeSplitVarint64 = function(lowBits, highBits) { + goog.asserts.assert(lowBits == Math.floor(lowBits)); + goog.asserts.assert(highBits == Math.floor(highBits)); + goog.asserts.assert((lowBits >= 0) && + (lowBits < jspb.BinaryConstants.TWO_TO_32)); + goog.asserts.assert((highBits >= 0) && + (highBits < jspb.BinaryConstants.TWO_TO_32)); + + // Break the binary representation into chunks of 7 bits, set the 8th bit + // in each chunk if it's not the final chunk, and append to the result. + while (highBits > 0 || lowBits > 127) { + this.buffer_.push((lowBits & 0x7f) | 0x80); + lowBits = ((lowBits >>> 7) | (highBits << 25)) >>> 0; + highBits = highBits >>> 7; + } + this.buffer_.push(lowBits); +}; + + +/** + * Encodes a 32-bit unsigned integer into its wire-format varint representation + * and stores it in the buffer. + * @param {number} value The integer to convert. + */ +jspb.BinaryEncoder.prototype.writeUnsignedVarint32 = function(value) { + goog.asserts.assert(value == Math.floor(value)); + goog.asserts.assert((value >= 0) && + (value < jspb.BinaryConstants.TWO_TO_32)); + + while (value > 127) { + this.buffer_.push((value & 0x7f) | 0x80); + value = value >>> 7; + } + + this.buffer_.push(value); +}; + + +/** + * Encodes a 32-bit signed integer into its wire-format varint representation + * and stores it in the buffer. + * @param {number} value The integer to convert. + */ +jspb.BinaryEncoder.prototype.writeSignedVarint32 = function(value) { + goog.asserts.assert(value == Math.floor(value)); + goog.asserts.assert((value >= -jspb.BinaryConstants.TWO_TO_31) && + (value < jspb.BinaryConstants.TWO_TO_31)); + + // Use the unsigned version if the value is not negative. + if (value >= 0) { + this.writeUnsignedVarint32(value); + return; + } + + // Write nine bytes with a _signed_ right shift so we preserve the sign bit. + for (var i = 0; i < 9; i++) { + this.buffer_.push((value & 0x7f) | 0x80); + value = value >> 7; + } + + // The above loop writes out 63 bits, so the last byte is always the sign bit + // which is always set for negative numbers. + this.buffer_.push(1); +}; + + +/** + * Encodes a 64-bit unsigned integer into its wire-format varint representation + * and stores it in the buffer. Integers that are not representable in 64 bits + * will be truncated. + * @param {number} value The integer to convert. + */ +jspb.BinaryEncoder.prototype.writeUnsignedVarint64 = function(value) { + goog.asserts.assert(value == Math.floor(value)); + goog.asserts.assert((value >= 0) && + (value < jspb.BinaryConstants.TWO_TO_64)); + jspb.utils.splitInt64(value); + this.writeSplitVarint64(jspb.utils.split64Low, + jspb.utils.split64High); +}; + + +/** + * Encodes a 64-bit signed integer into its wire-format varint representation + * and stores it in the buffer. Integers that are not representable in 64 bits + * will be truncated. + * @param {number} value The integer to convert. + */ +jspb.BinaryEncoder.prototype.writeSignedVarint64 = function(value) { + goog.asserts.assert(value == Math.floor(value)); + goog.asserts.assert((value >= -jspb.BinaryConstants.TWO_TO_63) && + (value < jspb.BinaryConstants.TWO_TO_63)); + jspb.utils.splitInt64(value); + this.writeSplitVarint64(jspb.utils.split64Low, + jspb.utils.split64High); +}; + + +/** + * Encodes a JavaScript integer into its wire-format, zigzag-encoded varint + * representation and stores it in the buffer. + * @param {number} value The integer to convert. + */ +jspb.BinaryEncoder.prototype.writeZigzagVarint32 = function(value) { + goog.asserts.assert(value == Math.floor(value)); + goog.asserts.assert((value >= -jspb.BinaryConstants.TWO_TO_31) && + (value < jspb.BinaryConstants.TWO_TO_31)); + this.writeUnsignedVarint32(((value << 1) ^ (value >> 31)) >>> 0); +}; + + +/** + * Encodes a JavaScript integer into its wire-format, zigzag-encoded varint + * representation and stores it in the buffer. Integers not representable in 64 + * bits will be truncated. + * @param {number} value The integer to convert. + */ +jspb.BinaryEncoder.prototype.writeZigzagVarint64 = function(value) { + goog.asserts.assert(value == Math.floor(value)); + goog.asserts.assert((value >= -jspb.BinaryConstants.TWO_TO_63) && + (value < jspb.BinaryConstants.TWO_TO_63)); + jspb.utils.splitZigzag64(value); + this.writeSplitVarint64(jspb.utils.split64Low, + jspb.utils.split64High); +}; + + +/** + * Writes a 8-bit unsigned integer to the buffer. Numbers outside the range + * [0,2^8) will be truncated. + * @param {number} value The value to write. + */ +jspb.BinaryEncoder.prototype.writeUint8 = function(value) { + goog.asserts.assert(value == Math.floor(value)); + goog.asserts.assert((value >= 0) && (value < 256)); + this.buffer_.push((value >>> 0) & 0xFF); +}; + + +/** + * Writes a 16-bit unsigned integer to the buffer. Numbers outside the + * range [0,2^16) will be truncated. + * @param {number} value The value to write. + */ +jspb.BinaryEncoder.prototype.writeUint16 = function(value) { + goog.asserts.assert(value == Math.floor(value)); + goog.asserts.assert((value >= 0) && (value < 65536)); + this.buffer_.push((value >>> 0) & 0xFF); + this.buffer_.push((value >>> 8) & 0xFF); +}; + + +/** + * Writes a 32-bit unsigned integer to the buffer. Numbers outside the + * range [0,2^32) will be truncated. + * @param {number} value The value to write. + */ +jspb.BinaryEncoder.prototype.writeUint32 = function(value) { + goog.asserts.assert(value == Math.floor(value)); + goog.asserts.assert((value >= 0) && + (value < jspb.BinaryConstants.TWO_TO_32)); + this.buffer_.push((value >>> 0) & 0xFF); + this.buffer_.push((value >>> 8) & 0xFF); + this.buffer_.push((value >>> 16) & 0xFF); + this.buffer_.push((value >>> 24) & 0xFF); +}; + + +/** + * Writes a 64-bit unsigned integer to the buffer. Numbers outside the + * range [0,2^64) will be truncated. + * @param {number} value The value to write. + */ +jspb.BinaryEncoder.prototype.writeUint64 = function(value) { + goog.asserts.assert(value == Math.floor(value)); + goog.asserts.assert((value >= 0) && + (value < jspb.BinaryConstants.TWO_TO_64)); + jspb.utils.splitUint64(value); + this.writeUint32(jspb.utils.split64Low); + this.writeUint32(jspb.utils.split64High); +}; + + +/** + * Writes a 8-bit integer to the buffer. Numbers outside the range + * [-2^7,2^7) will be truncated. + * @param {number} value The value to write. + */ +jspb.BinaryEncoder.prototype.writeInt8 = function(value) { + goog.asserts.assert(value == Math.floor(value)); + goog.asserts.assert((value >= -128) && (value < 128)); + this.buffer_.push((value >>> 0) & 0xFF); +}; + + +/** + * Writes a 16-bit integer to the buffer. Numbers outside the range + * [-2^15,2^15) will be truncated. + * @param {number} value The value to write. + */ +jspb.BinaryEncoder.prototype.writeInt16 = function(value) { + goog.asserts.assert(value == Math.floor(value)); + goog.asserts.assert((value >= -32768) && (value < 32768)); + this.buffer_.push((value >>> 0) & 0xFF); + this.buffer_.push((value >>> 8) & 0xFF); +}; + + +/** + * Writes a 32-bit integer to the buffer. Numbers outside the range + * [-2^31,2^31) will be truncated. + * @param {number} value The value to write. + */ +jspb.BinaryEncoder.prototype.writeInt32 = function(value) { + goog.asserts.assert(value == Math.floor(value)); + goog.asserts.assert((value >= -jspb.BinaryConstants.TWO_TO_31) && + (value < jspb.BinaryConstants.TWO_TO_31)); + this.buffer_.push((value >>> 0) & 0xFF); + this.buffer_.push((value >>> 8) & 0xFF); + this.buffer_.push((value >>> 16) & 0xFF); + this.buffer_.push((value >>> 24) & 0xFF); +}; + + +/** + * Writes a 64-bit integer to the buffer. Numbers outside the range + * [-2^63,2^63) will be truncated. + * @param {number} value The value to write. + */ +jspb.BinaryEncoder.prototype.writeInt64 = function(value) { + goog.asserts.assert(value == Math.floor(value)); + goog.asserts.assert((value >= -jspb.BinaryConstants.TWO_TO_63) && + (value < jspb.BinaryConstants.TWO_TO_63)); + jspb.utils.splitInt64(value); + this.writeUint32(jspb.utils.split64Low); + this.writeUint32(jspb.utils.split64High); +}; + + +/** + * Writes a single-precision floating point value to the buffer. Numbers + * requiring more than 32 bits of precision will be truncated. + * @param {number} value The value to write. + */ +jspb.BinaryEncoder.prototype.writeFloat = function(value) { + goog.asserts.assert((value >= -jspb.BinaryConstants.FLOAT32_MAX) && + (value <= jspb.BinaryConstants.FLOAT32_MAX)); + jspb.utils.splitFloat32(value); + this.writeUint32(jspb.utils.split64Low); +}; + + +/** + * Writes a double-precision floating point value to the buffer. As this is + * the native format used by JavaScript, no precision will be lost. + * @param {number} value The value to write. + */ +jspb.BinaryEncoder.prototype.writeDouble = function(value) { + goog.asserts.assert((value >= -jspb.BinaryConstants.FLOAT64_MAX) && + (value <= jspb.BinaryConstants.FLOAT64_MAX)); + jspb.utils.splitFloat64(value); + this.writeUint32(jspb.utils.split64Low); + this.writeUint32(jspb.utils.split64High); +}; + + +/** + * Writes a boolean value to the buffer as a varint. + * @param {boolean} value The value to write. + */ +jspb.BinaryEncoder.prototype.writeBool = function(value) { + goog.asserts.assert(goog.isBoolean(value)); + this.buffer_.push(value ? 1 : 0); +}; + + +/** + * Writes an enum value to the buffer as a varint. + * @param {number} value The value to write. + */ +jspb.BinaryEncoder.prototype.writeEnum = function(value) { + goog.asserts.assert(value == Math.floor(value)); + goog.asserts.assert((value >= -jspb.BinaryConstants.TWO_TO_31) && + (value < jspb.BinaryConstants.TWO_TO_31)); + this.writeSignedVarint32(value); +}; + + +/** + * Writes an arbitrary byte array to the buffer. + * @param {!Uint8Array} bytes The array of bytes to write. + */ +jspb.BinaryEncoder.prototype.writeBytes = function(bytes) { + this.buffer_.push.apply(this.buffer_, bytes); +}; + + +/** + * Writes a 64-bit hash string (8 characters @ 8 bits of data each) to the + * buffer as a varint. + * @param {string} hash The hash to write. + */ +jspb.BinaryEncoder.prototype.writeVarintHash64 = function(hash) { + jspb.utils.splitHash64(hash); + this.writeSplitVarint64(jspb.utils.split64Low, + jspb.utils.split64High); +}; + + +/** + * Writes a 64-bit hash string (8 characters @ 8 bits of data each) to the + * buffer as a fixed64. + * @param {string} hash The hash to write. + */ +jspb.BinaryEncoder.prototype.writeFixedHash64 = function(hash) { + jspb.utils.splitHash64(hash); + this.writeUint32(jspb.utils.split64Low); + this.writeUint32(jspb.utils.split64High); +}; + + +/** + * Writes a UTF16 Javascript string to the buffer encoded as UTF8. + * TODO(aappleby): Add support for surrogate pairs, reject unpaired surrogates. + * @param {string} value The string to write. + * @return {number} The number of bytes used to encode the string. + */ +jspb.BinaryEncoder.prototype.writeString = function(value) { + var oldLength = this.buffer_.length; + + // UTF16 to UTF8 conversion loop swiped from goog.crypt.stringToUtf8ByteArray. + for (var i = 0; i < value.length; i++) { + var c = value.charCodeAt(i); + if (c < 128) { + this.buffer_.push(c); + } else if (c < 2048) { + this.buffer_.push((c >> 6) | 192); + this.buffer_.push((c & 63) | 128); + } else { + this.buffer_.push((c >> 12) | 224); + this.buffer_.push(((c >> 6) & 63) | 128); + this.buffer_.push((c & 63) | 128); + } + } + + var length = this.buffer_.length - oldLength; + return length; +}; |