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624 lines
23 KiB
JavaScript
624 lines
23 KiB
JavaScript
/**
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* unzip.js
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*
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* Copyright(c) 2011 Google Inc.
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* Copyright(c) 2011 antimatter15
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*
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* Reference Documentation:
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*
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* ZIP format: http://www.pkware.com/documents/casestudies/APPNOTE.TXT
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* DEFLATE format: http://tools.ietf.org/html/rfc1951
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*/
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/* global bitjs, importScripts, Uint8Array */
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// This file expects to be invoked as a Worker (see onmessage below).
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importScripts("io.js");
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importScripts("archive.js");
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// Progress variables.
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var currentFilename = "";
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var currentFileNumber = 0;
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var currentBytesUnarchivedInFile = 0;
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var currentBytesUnarchived = 0;
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var totalUncompressedBytesInArchive = 0;
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var totalFilesInArchive = 0;
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// Helper functions.
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var info = function(str) {
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postMessage(new bitjs.archive.UnarchiveInfoEvent(str));
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};
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var err = function(str) {
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postMessage(new bitjs.archive.UnarchiveErrorEvent(str));
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};
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var postProgress = function() {
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postMessage(new bitjs.archive.UnarchiveProgressEvent(
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currentFilename,
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currentFileNumber,
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currentBytesUnarchivedInFile,
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currentBytesUnarchived,
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totalUncompressedBytesInArchive,
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totalFilesInArchive));
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};
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var zLocalFileHeaderSignature = 0x04034b50;
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var zArchiveExtraDataSignature = 0x08064b50;
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var zCentralFileHeaderSignature = 0x02014b50;
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var zDigitalSignatureSignature = 0x05054b50;
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//var zEndOfCentralDirSignature = 0x06064b50;
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//var zEndOfCentralDirLocatorSignature = 0x07064b50;
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// takes a ByteStream and parses out the local file information
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var ZipLocalFile = function(bstream) {
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if (typeof bstream !== typeof {} || !bstream.readNumber || typeof bstream.readNumber !== typeof function() {} ) {
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return null;
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}
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bstream.readNumber(4); // swallow signature
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this.version = bstream.readNumber(2);
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this.generalPurpose = bstream.readNumber(2);
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this.compressionMethod = bstream.readNumber(2);
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this.lastModFileTime = bstream.readNumber(2);
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this.lastModFileDate = bstream.readNumber(2);
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this.crc32 = bstream.readNumber(4);
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this.compressedSize = bstream.readNumber(4);
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this.uncompressedSize = bstream.readNumber(4);
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this.fileNameLength = bstream.readNumber(2);
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this.extraFieldLength = bstream.readNumber(2);
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this.filename = null;
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if (this.fileNameLength > 0) {
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this.filename = bstream.readString(this.fileNameLength);
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}
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info("Zip Local File Header:");
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info(" version=" + this.version);
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info(" general purpose=" + this.generalPurpose);
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info(" compression method=" + this.compressionMethod);
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info(" last mod file time=" + this.lastModFileTime);
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info(" last mod file date=" + this.lastModFileDate);
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info(" crc32=" + this.crc32);
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info(" compressed size=" + this.compressedSize);
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info(" uncompressed size=" + this.uncompressedSize);
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info(" file name length=" + this.fileNameLength);
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info(" extra field length=" + this.extraFieldLength);
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info(" filename = '" + this.filename + "'");
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this.extraField = null;
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if (this.extraFieldLength > 0) {
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this.extraField = bstream.readString(this.extraFieldLength);
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info(" extra field=" + this.extraField);
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}
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// read in the compressed data
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this.fileData = null;
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if (this.compressedSize > 0) {
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this.fileData = new Uint8Array(bstream.bytes.buffer, bstream.ptr, this.compressedSize);
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bstream.ptr += this.compressedSize;
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}
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// TODO: deal with data descriptor if present (we currently assume no data descriptor!)
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// "This descriptor exists only if bit 3 of the general purpose bit flag is set"
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// But how do you figure out how big the file data is if you don't know the compressedSize
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// from the header?!?
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if ((this.generalPurpose & bitjs.BIT[3]) !== 0) {
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this.crc32 = bstream.readNumber(4);
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this.compressedSize = bstream.readNumber(4);
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this.uncompressedSize = bstream.readNumber(4);
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}
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};
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// determine what kind of compressed data we have and decompress
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ZipLocalFile.prototype.unzip = function() {
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// Zip Version 1.0, no compression (store only)
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if (this.compressionMethod === 0 ) {
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info("ZIP v" + this.version + ", store only: " + this.filename + " (" + this.compressedSize + " bytes)");
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currentBytesUnarchivedInFile = this.compressedSize;
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currentBytesUnarchived += this.compressedSize;
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} else if (this.compressionMethod === 8) {
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// version == 20, compression method == 8 (DEFLATE)
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info("ZIP v2.0, DEFLATE: " + this.filename + " (" + this.compressedSize + " bytes)");
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this.fileData = inflate(this.fileData, this.uncompressedSize);
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} else {
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err("UNSUPPORTED VERSION/FORMAT: ZIP v" + this.version + ", compression method=" + this.compressionMethod + ": " + this.filename + " (" + this.compressedSize + " bytes)");
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this.fileData = null;
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}
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};
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// Takes an ArrayBuffer of a zip file in
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// returns null on error
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// returns an array of DecompressedFile objects on success
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var unzip = function(arrayBuffer) {
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postMessage(new bitjs.archive.UnarchiveStartEvent());
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currentFilename = "";
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currentFileNumber = 0;
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currentBytesUnarchivedInFile = 0;
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currentBytesUnarchived = 0;
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totalUncompressedBytesInArchive = 0;
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totalFilesInArchive = 0;
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currentBytesUnarchived = 0;
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var bstream = new bitjs.io.ByteStream(arrayBuffer);
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// detect local file header signature or return null
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if (bstream.peekNumber(4) === zLocalFileHeaderSignature) {
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var localFiles = [];
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// loop until we don't see any more local files
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while (bstream.peekNumber(4) === zLocalFileHeaderSignature) {
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var oneLocalFile = new ZipLocalFile(bstream);
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// this should strip out directories/folders
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if (oneLocalFile && oneLocalFile.uncompressedSize > 0 && oneLocalFile.fileData) {
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localFiles.push(oneLocalFile);
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totalUncompressedBytesInArchive += oneLocalFile.uncompressedSize;
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}
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}
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totalFilesInArchive = localFiles.length;
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// got all local files, now sort them
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localFiles.sort(function(a, b) {
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var aname = a.filename.toLowerCase();
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var bname = b.filename.toLowerCase();
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return aname > bname ? 1 : -1;
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});
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// archive extra data record
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if (bstream.peekNumber(4) === zArchiveExtraDataSignature) {
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info(" Found an Archive Extra Data Signature");
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// skipping this record for now
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bstream.readNumber(4);
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var archiveExtraFieldLength = bstream.readNumber(4);
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bstream.readString(archiveExtraFieldLength);
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}
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// central directory structure
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// TODO: handle the rest of the structures (Zip64 stuff)
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if (bstream.peekNumber(4) === zCentralFileHeaderSignature) {
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info(" Found a Central File Header");
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// read all file headers
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while (bstream.peekNumber(4) === zCentralFileHeaderSignature) {
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bstream.readNumber(4); // signature
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bstream.readNumber(2); // version made by
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bstream.readNumber(2); // version needed to extract
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bstream.readNumber(2); // general purpose bit flag
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bstream.readNumber(2); // compression method
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bstream.readNumber(2); // last mod file time
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bstream.readNumber(2); // last mod file date
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bstream.readNumber(4); // crc32
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bstream.readNumber(4); // compressed size
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bstream.readNumber(4); // uncompressed size
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var fileNameLength = bstream.readNumber(2); // file name length
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var extraFieldLength = bstream.readNumber(2); // extra field length
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var fileCommentLength = bstream.readNumber(2); // file comment length
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bstream.readNumber(2); // disk number start
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bstream.readNumber(2); // internal file attributes
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bstream.readNumber(4); // external file attributes
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bstream.readNumber(4); // relative offset of local header
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bstream.readString(fileNameLength); // file name
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bstream.readString(extraFieldLength); // extra field
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bstream.readString(fileCommentLength); // file comment
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}
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}
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// digital signature
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if (bstream.peekNumber(4) === zDigitalSignatureSignature) {
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info(" Found a Digital Signature");
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bstream.readNumber(4);
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var sizeOfSignature = bstream.readNumber(2);
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bstream.readString(sizeOfSignature); // digital signature data
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}
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// report # files and total length
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if (localFiles.length > 0) {
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postProgress();
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}
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// now do the unzipping of each file
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for (var i = 0; i < localFiles.length; ++i) {
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var localfile = localFiles[i];
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// update progress
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currentFilename = localfile.filename;
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currentFileNumber = i;
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currentBytesUnarchivedInFile = 0;
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// actually do the unzipping
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localfile.unzip();
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if (localfile.fileData !== null) {
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postMessage(new bitjs.archive.UnarchiveExtractEvent(localfile));
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postProgress();
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}
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}
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postProgress();
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postMessage(new bitjs.archive.UnarchiveFinishEvent());
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}
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};
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// returns a table of Huffman codes
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// each entry's index is its code and its value is a JavaScript object
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// containing {length: 6, symbol: X}
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function getHuffmanCodes(bitLengths) {
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var len;
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// ensure bitLengths is an array containing at least one element
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if (typeof bitLengths !== typeof [] || bitLengths.length < 1) {
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err("Error! getHuffmanCodes() called with an invalid array");
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return null;
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}
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// Reference: http://tools.ietf.org/html/rfc1951#page-8
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var numLengths = bitLengths.length,
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blCount = [],
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MAX_BITS = 1;
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// Step 1: count up how many codes of each length we have
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for (var i = 0; i < numLengths; ++i) {
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len = bitLengths[i];
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// test to ensure each bit length is a positive, non-zero number
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if (typeof len !== typeof 1 || len < 0) {
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err("bitLengths contained an invalid number in getHuffmanCodes(): " + len + " of type " + (typeof len));
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return null;
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}
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// increment the appropriate bitlength count
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if (blCount[len] === undefined) blCount[len] = 0;
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// a length of zero means this symbol is not participating in the huffman coding
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if (len > 0) blCount[len]++;
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if (len > MAX_BITS) MAX_BITS = len;
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}
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// Step 2: Find the numerical value of the smallest code for each code length
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var nextCode = [],
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code = 0;
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for (var bits = 1; bits <= MAX_BITS; ++bits) {
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len = bits - 1;
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// ensure undefined lengths are zero
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if (blCount[len] === undefined) blCount[len] = 0;
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code = (code + blCount[bits - 1]) << 1;
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nextCode[bits] = code;
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}
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// Step 3: Assign numerical values to all codes
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var table = {}, tableLength = 0;
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for (var n = 0; n < numLengths; ++n) {
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len = bitLengths[n];
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if (len !== 0) {
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table[nextCode[len]] = { length: len, symbol: n }; //, bitstring: binaryValueToString(nextCode[len],len) };
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tableLength++;
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nextCode[len]++;
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}
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}
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table.maxLength = tableLength;
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return table;
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}
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/*
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The Huffman codes for the two alphabets are fixed, and are not
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represented explicitly in the data. The Huffman code lengths
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for the literal/length alphabet are:
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Lit Value Bits Codes
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--------- ---- -----
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0 - 143 8 00110000 through
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10111111
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144 - 255 9 110010000 through
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111111111
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256 - 279 7 0000000 through
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0010111
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280 - 287 8 11000000 through
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11000111
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*/
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// fixed Huffman codes go from 7-9 bits, so we need an array whose index can hold up to 9 bits
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var fixedHCtoLiteral = null;
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var fixedHCtoDistance = null;
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function getFixedLiteralTable() {
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var i;
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// create once
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if (!fixedHCtoLiteral) {
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var bitlengths = new Array(288);
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for (i = 0; i <= 143; ++i) bitlengths[i] = 8;
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for (i = 144; i <= 255; ++i) bitlengths[i] = 9;
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for (i = 256; i <= 279; ++i) bitlengths[i] = 7;
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for (i = 280; i <= 287; ++i) bitlengths[i] = 8;
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// get huffman code table
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fixedHCtoLiteral = getHuffmanCodes(bitlengths);
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}
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return fixedHCtoLiteral;
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}
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function getFixedDistanceTable() {
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// create once
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if (!fixedHCtoDistance) {
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var bitlengths = new Array(32);
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for (var i = 0; i < 32; ++i) {
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bitlengths[i] = 5;
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}
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// get huffman code table
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fixedHCtoDistance = getHuffmanCodes(bitlengths);
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}
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return fixedHCtoDistance;
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}
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// extract one bit at a time until we find a matching Huffman Code
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// then return that symbol
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function decodeSymbol(bstream, hcTable) {
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var code = 0, len = 0;
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// var match = false;
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// loop until we match
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for (;;) {
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// read in next bit
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var bit = bstream.readBits(1);
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code = (code << 1) | bit;
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++len;
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// check against Huffman Code table and break if found
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if (hcTable.hasOwnProperty(code) && hcTable[code].length === len) {
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break;
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}
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if (len > hcTable.maxLength) {
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err("Bit stream out of sync, didn't find a Huffman Code, length was " + len +
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" and table only max code length of " + hcTable.maxLength);
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break;
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}
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}
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return hcTable[code].symbol;
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}
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var CodeLengthCodeOrder = [16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15];
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/*
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Extra Extra Extra
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Code Bits Length(s) Code Bits Lengths Code Bits Length(s)
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---- ---- ------ ---- ---- ------- ---- ---- -------
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257 0 3 267 1 15,16 277 4 67-82
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258 0 4 268 1 17,18 278 4 83-98
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259 0 5 269 2 19-22 279 4 99-114
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260 0 6 270 2 23-26 280 4 115-130
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261 0 7 271 2 27-30 281 5 131-162
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262 0 8 272 2 31-34 282 5 163-194
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263 0 9 273 3 35-42 283 5 195-226
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264 0 10 274 3 43-50 284 5 227-257
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265 1 11,12 275 3 51-58 285 0 258
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266 1 13,14 276 3 59-66
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*/
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var LengthLookupTable = [
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[0, 3], [0, 4], [0, 5], [0, 6],
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[0, 7], [0, 8], [0, 9], [0, 10],
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[1, 11], [1, 13], [1, 15], [1, 17],
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[2, 19], [2, 23], [2, 27], [2, 31],
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[3, 35], [3, 43], [3, 51], [3, 59],
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[4, 67], [4, 83], [4, 99], [4, 115],
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[5, 131], [5, 163], [5, 195], [5, 227],
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[0, 258]
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];
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/*
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Extra Extra Extra
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Code Bits Dist Code Bits Dist Code Bits Distance
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---- ---- ---- ---- ---- ------ ---- ---- --------
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0 0 1 10 4 33-48 20 9 1025-1536
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1 0 2 11 4 49-64 21 9 1537-2048
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2 0 3 12 5 65-96 22 10 2049-3072
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3 0 4 13 5 97-128 23 10 3073-4096
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4 1 5,6 14 6 129-192 24 11 4097-6144
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5 1 7,8 15 6 193-256 25 11 6145-8192
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6 2 9-12 16 7 257-384 26 12 8193-12288
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7 2 13-16 17 7 385-512 27 12 12289-16384
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8 3 17-24 18 8 513-768 28 13 16385-24576
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9 3 25-32 19 8 769-1024 29 13 24577-32768
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*/
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var DistLookupTable = [
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[0, 1], [0, 2], [0, 3], [0, 4],
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[1, 5], [1, 7],
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[2, 9], [2, 13],
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[3, 17], [3, 25],
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[4, 33], [4, 49],
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[5, 65], [5, 97],
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[6, 129], [6, 193],
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[7, 257], [7, 385],
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[8, 513], [8, 769],
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[9, 1025], [9, 1537],
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[10, 2049], [10, 3073],
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[11, 4097], [11, 6145],
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[12, 8193], [12, 12289],
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[13, 16385], [13, 24577]
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];
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function inflateBlockData(bstream, hcLiteralTable, hcDistanceTable, buffer) {
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/*
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loop (until end of block code recognized)
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decode literal/length value from input stream
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if value < 256
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copy value (literal byte) to output stream
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otherwise
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if value = end of block (256)
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break from loop
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otherwise (value = 257..285)
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decode distance from input stream
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move backwards distance bytes in the output
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stream, and copy length bytes from this
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position to the output stream.
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*/
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var blockSize = 0;
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for (;;) {
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var symbol = decodeSymbol(bstream, hcLiteralTable);
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// ++numSymbols;
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if (symbol < 256) {
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// copy literal byte to output
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buffer.insertByte(symbol);
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blockSize++;
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}
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else {
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// end of block reached
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if (symbol === 256) {
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break;
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}
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else {
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var lengthLookup = LengthLookupTable[symbol - 257],
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length = lengthLookup[1] + bstream.readBits(lengthLookup[0]),
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distLookup = DistLookupTable[decodeSymbol(bstream, hcDistanceTable)],
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distance = distLookup[1] + bstream.readBits(distLookup[0]);
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// now apply length and distance appropriately and copy to output
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// TODO: check that backward distance < data.length?
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// http://tools.ietf.org/html/rfc1951#page-11
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// "Note also that the referenced string may overlap the current
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// position; for example, if the last 2 bytes decoded have values
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// X and Y, a string reference with <length = 5, distance = 2>
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// adds X,Y,X,Y,X to the output stream."
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//
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// loop for each character
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var ch = buffer.ptr - distance;
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blockSize += length;
|
|
if (length > distance) {
|
|
var data = buffer.data;
|
|
while (length--) {
|
|
buffer.insertByte(data[ch++]);
|
|
}
|
|
} else {
|
|
buffer.insertBytes(buffer.data.subarray(ch, ch + length));
|
|
}
|
|
|
|
} // length-distance pair
|
|
} // length-distance pair or end-of-block
|
|
} // loop until we reach end of block
|
|
return blockSize;
|
|
}
|
|
|
|
// {Uint8Array} compressedData A Uint8Array of the compressed file data.
|
|
// compression method 8
|
|
// deflate: http://tools.ietf.org/html/rfc1951
|
|
function inflate(compressedData, numDecompressedBytes) {
|
|
// Bit stream representing the compressed data.
|
|
var bstream = new bitjs.io.BitStream(compressedData.buffer,
|
|
false /* rtl */,
|
|
compressedData.byteOffset,
|
|
compressedData.byteLength);
|
|
var buffer = new bitjs.io.ByteBuffer(numDecompressedBytes);
|
|
//var numBlocks = 0;
|
|
var blockSize = 0;
|
|
var bFinal;
|
|
// block format: http://tools.ietf.org/html/rfc1951#page-9
|
|
do {
|
|
bFinal = bstream.readBits(1);
|
|
var bType = bstream.readBits(2);
|
|
blockSize = 0;
|
|
// ++numBlocks;
|
|
// no compression
|
|
if (bType === 0) {
|
|
// skip remaining bits in this byte
|
|
while (bstream.bitPtr !== 0) bstream.readBits(1);
|
|
var len = bstream.readBits(16),
|
|
// nlen = bstream.readBits(16);
|
|
// TODO: check if nlen is the ones-complement of len?
|
|
|
|
if (len > 0) buffer.insertBytes(bstream.readBytes(len));
|
|
blockSize = len;
|
|
}
|
|
// fixed Huffman codes
|
|
else if (bType === 1) {
|
|
blockSize = inflateBlockData(bstream, getFixedLiteralTable(), getFixedDistanceTable(), buffer);
|
|
}
|
|
// dynamic Huffman codes
|
|
else if (bType === 2) {
|
|
var numLiteralLengthCodes = bstream.readBits(5) + 257;
|
|
var numDistanceCodes = bstream.readBits(5) + 1,
|
|
numCodeLengthCodes = bstream.readBits(4) + 4;
|
|
|
|
// populate the array of code length codes (first de-compaction)
|
|
var codeLengthsCodeLengths = [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0];
|
|
for (var i = 0; i < numCodeLengthCodes; ++i) {
|
|
codeLengthsCodeLengths[ CodeLengthCodeOrder[i] ] = bstream.readBits(3);
|
|
}
|
|
|
|
// get the Huffman Codes for the code lengths
|
|
var codeLengthsCodes = getHuffmanCodes(codeLengthsCodeLengths);
|
|
|
|
// now follow this mapping
|
|
/*
|
|
0 - 15: Represent code lengths of 0 - 15
|
|
16: Copy the previous code length 3 - 6 times.
|
|
The next 2 bits indicate repeat length
|
|
(0 = 3, ... , 3 = 6)
|
|
Example: Codes 8, 16 (+2 bits 11),
|
|
16 (+2 bits 10) will expand to
|
|
12 code lengths of 8 (1 + 6 + 5)
|
|
17: Repeat a code length of 0 for 3 - 10 times.
|
|
(3 bits of length)
|
|
18: Repeat a code length of 0 for 11 - 138 times
|
|
(7 bits of length)
|
|
*/
|
|
// to generate the true code lengths of the Huffman Codes for the literal
|
|
// and distance tables together
|
|
var literalCodeLengths = [];
|
|
var prevCodeLength = 0;
|
|
while (literalCodeLengths.length < numLiteralLengthCodes + numDistanceCodes) {
|
|
var symbol = decodeSymbol(bstream, codeLengthsCodes);
|
|
var repeat;
|
|
if (symbol <= 15) {
|
|
literalCodeLengths.push(symbol);
|
|
prevCodeLength = symbol;
|
|
}
|
|
else if (symbol === 16) {
|
|
repeat = bstream.readBits(2) + 3;
|
|
while (repeat--) {
|
|
literalCodeLengths.push(prevCodeLength);
|
|
}
|
|
}
|
|
else if (symbol === 17) {
|
|
repeat = bstream.readBits(3) + 3;
|
|
while (repeat--) {
|
|
literalCodeLengths.push(0);
|
|
}
|
|
}
|
|
else if (symbol === 18) {
|
|
repeat = bstream.readBits(7) + 11;
|
|
while (repeat--) {
|
|
literalCodeLengths.push(0);
|
|
}
|
|
}
|
|
}
|
|
|
|
// now split the distance code lengths out of the literal code array
|
|
var distanceCodeLengths = literalCodeLengths.splice(numLiteralLengthCodes, numDistanceCodes);
|
|
|
|
// now generate the true Huffman Code tables using these code lengths
|
|
var hcLiteralTable = getHuffmanCodes(literalCodeLengths),
|
|
hcDistanceTable = getHuffmanCodes(distanceCodeLengths);
|
|
blockSize = inflateBlockData(bstream, hcLiteralTable, hcDistanceTable, buffer);
|
|
}
|
|
// error
|
|
else {
|
|
err("Error! Encountered deflate block of type 3");
|
|
return null;
|
|
}
|
|
|
|
// update progress
|
|
currentBytesUnarchivedInFile += blockSize;
|
|
currentBytesUnarchived += blockSize;
|
|
postProgress();
|
|
|
|
} while (bFinal !== 1);
|
|
// we are done reading blocks if the bFinal bit was set for this block
|
|
|
|
// return the buffer data bytes
|
|
return buffer.data;
|
|
}
|
|
|
|
// event.data.file has the ArrayBuffer.
|
|
onmessage = function(event) {
|
|
unzip(event.data.file, true);
|
|
};
|