262 lines
12 KiB
JavaScript
262 lines
12 KiB
JavaScript
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"use strict";
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var readerFor = require("./reader/readerFor");
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var utils = require("./utils");
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var sig = require("./signature");
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var ZipEntry = require("./zipEntry");
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var support = require("./support");
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// class ZipEntries {{{
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/**
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* All the entries in the zip file.
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* @constructor
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* @param {Object} loadOptions Options for loading the stream.
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*/
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function ZipEntries(loadOptions) {
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this.files = [];
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this.loadOptions = loadOptions;
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}
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ZipEntries.prototype = {
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/**
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* Check that the reader is on the specified signature.
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* @param {string} expectedSignature the expected signature.
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* @throws {Error} if it is an other signature.
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*/
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checkSignature: function(expectedSignature) {
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if (!this.reader.readAndCheckSignature(expectedSignature)) {
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this.reader.index -= 4;
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var signature = this.reader.readString(4);
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throw new Error("Corrupted zip or bug: unexpected signature " + "(" + utils.pretty(signature) + ", expected " + utils.pretty(expectedSignature) + ")");
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}
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},
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/**
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* Check if the given signature is at the given index.
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* @param {number} askedIndex the index to check.
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* @param {string} expectedSignature the signature to expect.
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* @return {boolean} true if the signature is here, false otherwise.
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*/
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isSignature: function(askedIndex, expectedSignature) {
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var currentIndex = this.reader.index;
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this.reader.setIndex(askedIndex);
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var signature = this.reader.readString(4);
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var result = signature === expectedSignature;
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this.reader.setIndex(currentIndex);
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return result;
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},
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/**
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* Read the end of the central directory.
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*/
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readBlockEndOfCentral: function() {
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this.diskNumber = this.reader.readInt(2);
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this.diskWithCentralDirStart = this.reader.readInt(2);
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this.centralDirRecordsOnThisDisk = this.reader.readInt(2);
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this.centralDirRecords = this.reader.readInt(2);
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this.centralDirSize = this.reader.readInt(4);
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this.centralDirOffset = this.reader.readInt(4);
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this.zipCommentLength = this.reader.readInt(2);
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// warning : the encoding depends of the system locale
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// On a linux machine with LANG=en_US.utf8, this field is utf8 encoded.
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// On a windows machine, this field is encoded with the localized windows code page.
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var zipComment = this.reader.readData(this.zipCommentLength);
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var decodeParamType = support.uint8array ? "uint8array" : "array";
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// To get consistent behavior with the generation part, we will assume that
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// this is utf8 encoded unless specified otherwise.
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var decodeContent = utils.transformTo(decodeParamType, zipComment);
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this.zipComment = this.loadOptions.decodeFileName(decodeContent);
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},
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/**
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* Read the end of the Zip 64 central directory.
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* Not merged with the method readEndOfCentral :
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* The end of central can coexist with its Zip64 brother,
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* I don't want to read the wrong number of bytes !
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*/
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readBlockZip64EndOfCentral: function() {
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this.zip64EndOfCentralSize = this.reader.readInt(8);
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this.reader.skip(4);
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// this.versionMadeBy = this.reader.readString(2);
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// this.versionNeeded = this.reader.readInt(2);
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this.diskNumber = this.reader.readInt(4);
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this.diskWithCentralDirStart = this.reader.readInt(4);
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this.centralDirRecordsOnThisDisk = this.reader.readInt(8);
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this.centralDirRecords = this.reader.readInt(8);
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this.centralDirSize = this.reader.readInt(8);
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this.centralDirOffset = this.reader.readInt(8);
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this.zip64ExtensibleData = {};
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var extraDataSize = this.zip64EndOfCentralSize - 44,
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index = 0,
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extraFieldId,
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extraFieldLength,
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extraFieldValue;
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while (index < extraDataSize) {
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extraFieldId = this.reader.readInt(2);
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extraFieldLength = this.reader.readInt(4);
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extraFieldValue = this.reader.readData(extraFieldLength);
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this.zip64ExtensibleData[extraFieldId] = {
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id: extraFieldId,
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length: extraFieldLength,
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value: extraFieldValue
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};
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}
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},
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/**
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* Read the end of the Zip 64 central directory locator.
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*/
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readBlockZip64EndOfCentralLocator: function() {
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this.diskWithZip64CentralDirStart = this.reader.readInt(4);
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this.relativeOffsetEndOfZip64CentralDir = this.reader.readInt(8);
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this.disksCount = this.reader.readInt(4);
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if (this.disksCount > 1) {
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throw new Error("Multi-volumes zip are not supported");
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}
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},
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/**
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* Read the local files, based on the offset read in the central part.
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*/
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readLocalFiles: function() {
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var i, file;
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for (i = 0; i < this.files.length; i++) {
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file = this.files[i];
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this.reader.setIndex(file.localHeaderOffset);
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this.checkSignature(sig.LOCAL_FILE_HEADER);
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file.readLocalPart(this.reader);
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file.handleUTF8();
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file.processAttributes();
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}
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},
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/**
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* Read the central directory.
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*/
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readCentralDir: function() {
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var file;
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this.reader.setIndex(this.centralDirOffset);
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while (this.reader.readAndCheckSignature(sig.CENTRAL_FILE_HEADER)) {
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file = new ZipEntry({
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zip64: this.zip64
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}, this.loadOptions);
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file.readCentralPart(this.reader);
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this.files.push(file);
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}
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if (this.centralDirRecords !== this.files.length) {
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if (this.centralDirRecords !== 0 && this.files.length === 0) {
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// We expected some records but couldn't find ANY.
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// This is really suspicious, as if something went wrong.
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throw new Error("Corrupted zip or bug: expected " + this.centralDirRecords + " records in central dir, got " + this.files.length);
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} else {
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// We found some records but not all.
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// Something is wrong but we got something for the user: no error here.
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// console.warn("expected", this.centralDirRecords, "records in central dir, got", this.files.length);
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}
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}
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},
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/**
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* Read the end of central directory.
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*/
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readEndOfCentral: function() {
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var offset = this.reader.lastIndexOfSignature(sig.CENTRAL_DIRECTORY_END);
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if (offset < 0) {
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// Check if the content is a truncated zip or complete garbage.
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// A "LOCAL_FILE_HEADER" is not required at the beginning (auto
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// extractible zip for example) but it can give a good hint.
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// If an ajax request was used without responseType, we will also
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// get unreadable data.
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var isGarbage = !this.isSignature(0, sig.LOCAL_FILE_HEADER);
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if (isGarbage) {
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throw new Error("Can't find end of central directory : is this a zip file ? " +
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"If it is, see https://stuk.github.io/jszip/documentation/howto/read_zip.html");
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} else {
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throw new Error("Corrupted zip: can't find end of central directory");
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}
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}
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this.reader.setIndex(offset);
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var endOfCentralDirOffset = offset;
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this.checkSignature(sig.CENTRAL_DIRECTORY_END);
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this.readBlockEndOfCentral();
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/* extract from the zip spec :
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4) If one of the fields in the end of central directory
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record is too small to hold required data, the field
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should be set to -1 (0xFFFF or 0xFFFFFFFF) and the
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ZIP64 format record should be created.
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5) The end of central directory record and the
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Zip64 end of central directory locator record must
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reside on the same disk when splitting or spanning
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an archive.
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*/
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if (this.diskNumber === utils.MAX_VALUE_16BITS || this.diskWithCentralDirStart === utils.MAX_VALUE_16BITS || this.centralDirRecordsOnThisDisk === utils.MAX_VALUE_16BITS || this.centralDirRecords === utils.MAX_VALUE_16BITS || this.centralDirSize === utils.MAX_VALUE_32BITS || this.centralDirOffset === utils.MAX_VALUE_32BITS) {
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this.zip64 = true;
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/*
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Warning : the zip64 extension is supported, but ONLY if the 64bits integer read from
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the zip file can fit into a 32bits integer. This cannot be solved : JavaScript represents
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all numbers as 64-bit double precision IEEE 754 floating point numbers.
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So, we have 53bits for integers and bitwise operations treat everything as 32bits.
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see https://developer.mozilla.org/en-US/docs/JavaScript/Reference/Operators/Bitwise_Operators
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and http://www.ecma-international.org/publications/files/ECMA-ST/ECMA-262.pdf section 8.5
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*/
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// should look for a zip64 EOCD locator
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offset = this.reader.lastIndexOfSignature(sig.ZIP64_CENTRAL_DIRECTORY_LOCATOR);
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if (offset < 0) {
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throw new Error("Corrupted zip: can't find the ZIP64 end of central directory locator");
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}
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this.reader.setIndex(offset);
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this.checkSignature(sig.ZIP64_CENTRAL_DIRECTORY_LOCATOR);
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this.readBlockZip64EndOfCentralLocator();
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// now the zip64 EOCD record
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if (!this.isSignature(this.relativeOffsetEndOfZip64CentralDir, sig.ZIP64_CENTRAL_DIRECTORY_END)) {
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// console.warn("ZIP64 end of central directory not where expected.");
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this.relativeOffsetEndOfZip64CentralDir = this.reader.lastIndexOfSignature(sig.ZIP64_CENTRAL_DIRECTORY_END);
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if (this.relativeOffsetEndOfZip64CentralDir < 0) {
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throw new Error("Corrupted zip: can't find the ZIP64 end of central directory");
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}
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}
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this.reader.setIndex(this.relativeOffsetEndOfZip64CentralDir);
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this.checkSignature(sig.ZIP64_CENTRAL_DIRECTORY_END);
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this.readBlockZip64EndOfCentral();
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}
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var expectedEndOfCentralDirOffset = this.centralDirOffset + this.centralDirSize;
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if (this.zip64) {
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expectedEndOfCentralDirOffset += 20; // end of central dir 64 locator
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expectedEndOfCentralDirOffset += 12 /* should not include the leading 12 bytes */ + this.zip64EndOfCentralSize;
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}
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var extraBytes = endOfCentralDirOffset - expectedEndOfCentralDirOffset;
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if (extraBytes > 0) {
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// console.warn(extraBytes, "extra bytes at beginning or within zipfile");
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if (this.isSignature(endOfCentralDirOffset, sig.CENTRAL_FILE_HEADER)) {
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// The offsets seem wrong, but we have something at the specified offset.
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// So… we keep it.
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} else {
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// the offset is wrong, update the "zero" of the reader
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// this happens if data has been prepended (crx files for example)
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this.reader.zero = extraBytes;
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}
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} else if (extraBytes < 0) {
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throw new Error("Corrupted zip: missing " + Math.abs(extraBytes) + " bytes.");
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}
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},
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prepareReader: function(data) {
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this.reader = readerFor(data);
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},
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/**
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* Read a zip file and create ZipEntries.
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* @param {String|ArrayBuffer|Uint8Array|Buffer} data the binary string representing a zip file.
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*/
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load: function(data) {
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this.prepareReader(data);
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this.readEndOfCentral();
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this.readCentralDir();
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this.readLocalFiles();
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}
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};
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// }}} end of ZipEntries
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module.exports = ZipEntries;
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