164 lines
4.4 KiB
JavaScript
164 lines
4.4 KiB
JavaScript
// GPG4Browsers - An OpenPGP implementation in javascript
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// Copyright (C) 2011 Recurity Labs GmbH
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//
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// This library is free software; you can redistribute it and/or
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// modify it under the terms of the GNU Lesser General Public
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// License as published by the Free Software Foundation; either
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// version 3.0 of the License, or (at your option) any later version.
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//
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// This library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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// Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public
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// License along with this library; if not, write to the Free Software
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// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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/**
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* Implementation of the Compressed Data Packet (Tag 8)<br/>
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* <br/>
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* {@link http://tools.ietf.org/html/rfc4880#section-5.6|RFC4880 5.6}: The Compressed Data packet contains compressed data. Typically,
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* this packet is found as the contents of an encrypted packet, or following
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* a Signature or One-Pass Signature packet, and contains a literal data packet.
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* @requires compression/zlib
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* @requires compression/rawinflate
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* @requires compression/rawdeflate
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* @requires enums
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* @requires util
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* @module packet/compressed
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*/
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'use strict';
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import enums from '../enums.js';
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import util from '../util.js';
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import Zlib from '../compression/zlib.min.js';
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import RawInflate from '../compression/rawinflate.min.js';
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import RawDeflate from '../compression/rawdeflate.min.js';
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/**
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* @constructor
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*/
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export default function Compressed() {
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/**
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* Packet type
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* @type {module:enums.packet}
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*/
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this.tag = enums.packet.compressed;
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/**
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* List of packets
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* @type {module:packet/packetlist}
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*/
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this.packets = null;
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/**
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* Compression algorithm
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* @type {compression}
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*/
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this.algorithm = 'zip';
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/**
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* Compressed packet data
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* @type {String}
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*/
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this.compressed = null;
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}
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/**
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* Parsing function for the packet.
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* @param {String} bytes Payload of a tag 8 packet
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*/
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Compressed.prototype.read = function (bytes) {
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// One octet that gives the algorithm used to compress the packet.
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this.algorithm = enums.read(enums.compression, bytes[0]);
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// Compressed data, which makes up the remainder of the packet.
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this.compressed = bytes.subarray(1, bytes.length);
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this.decompress();
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};
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/**
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* Return the compressed packet.
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* @return {String} binary compressed packet
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*/
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Compressed.prototype.write = function () {
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if (this.compressed === null) {
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this.compress();
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}
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return util.concatUint8Array(new Uint8Array([enums.write(enums.compression, this.algorithm)]), this.compressed);
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};
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/**
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* Decompression method for decompressing the compressed data
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* read by read_packet
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*/
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Compressed.prototype.decompress = function () {
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var decompressed, inflate;
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switch (this.algorithm) {
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case 'uncompressed':
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decompressed = this.compressed;
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break;
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case 'zip':
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inflate = new RawInflate.Zlib.RawInflate(this.compressed);
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decompressed = inflate.decompress();
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break;
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case 'zlib':
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inflate = new Zlib.Zlib.Inflate(this.compressed);
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decompressed = inflate.decompress();
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break;
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case 'bzip2':
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// TODO: need to implement this
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throw new Error('Compression algorithm BZip2 [BZ2] is not implemented.');
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default:
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throw new Error("Compression algorithm unknown :" + this.alogrithm);
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}
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this.packets.read(decompressed);
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};
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/**
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* Compress the packet data (member decompressedData)
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*/
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Compressed.prototype.compress = function () {
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var uncompressed, deflate;
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uncompressed = this.packets.write();
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switch (this.algorithm) {
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case 'uncompressed':
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// - Uncompressed
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this.compressed = uncompressed;
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break;
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case 'zip':
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// - ZIP [RFC1951]
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deflate = new RawDeflate.Zlib.RawDeflate(uncompressed);
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this.compressed = deflate.compress();
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break;
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case 'zlib':
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// - ZLIB [RFC1950]
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deflate = new Zlib.Zlib.Deflate(uncompressed);
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this.compressed = deflate.compress();
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break;
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case 'bzip2':
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// - BZip2 [BZ2]
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// TODO: need to implement this
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throw new Error("Compression algorithm BZip2 [BZ2] is not implemented.");
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default:
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throw new Error("Compression algorithm unknown :" + this.type);
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}
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};
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