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Move some common type definitions into archive/common.js and some comments.

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This commit is contained in:
Jeff Schiller 2024-01-20 16:12:55 -08:00
parent 4fc0c3da2b
commit 45fdedd663
11 changed files with 75 additions and 83 deletions
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36
archive/unzip.js
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@ -15,6 +15,9 @@
import { BitStream } from '../io/bitstream.js';
import { ByteBuffer } from '../io/bytebuffer.js';
import { ByteStream } from '../io/bytestream.js';
import { ARCHIVE_EXTRA_DATA_SIG, CENTRAL_FILE_HEADER_SIG, CRC32_MAGIC_NUMBER,
DATA_DESCRIPTOR_SIG, DIGITAL_SIGNATURE_SIG, END_OF_CENTRAL_DIR_SIG,
LOCAL_FILE_HEADER_SIG } from './common.js';
const UnarchiveState = {
NOT_STARTED: 0,
@ -28,6 +31,7 @@ let hostPort;
// State - consider putting these into a class.
let unarchiveState = UnarchiveState.NOT_STARTED;
/** @type {ByteStream} */
let bytestream = null;
let allLocalFiles = null;
let logToConsole = false;
@ -60,14 +64,6 @@ const postProgress = function () {
});
};
const zLocalFileHeaderSignature = 0x04034b50;
const zArchiveExtraDataSignature = 0x08064b50;
const zCentralFileHeaderSignature = 0x02014b50;
const zDigitalSignatureSignature = 0x05054b50;
const zEndOfCentralDirSignature = 0x06054b50;
const zEndOfCentralDirLocatorSignature = 0x07064b50;
const zDataDescriptorSignature = 0x08074b50;
// mask for getting the Nth bit (zero-based)
const BIT = [0x01, 0x02, 0x04, 0x08,
0x10, 0x20, 0x40, 0x80,
@ -75,9 +71,7 @@ const BIT = [0x01, 0x02, 0x04, 0x08,
0x1000, 0x2000, 0x4000, 0x8000];
class ZipLocalFile {
/**
* @param {ByteStream} bstream
*/
/** @param {ByteStream} bstream */
constructor(bstream) {
if (typeof bstream != typeof {} || !bstream.readNumber || typeof bstream.readNumber != typeof function () { }) {
return null;
@ -125,9 +119,9 @@ class ZipLocalFile {
let foundDataDescriptor = false;
let numBytesSeeked = 0;
while (!foundDataDescriptor) {
while (bstream.peekNumber(4) !== zLocalFileHeaderSignature &&
bstream.peekNumber(4) !== zArchiveExtraDataSignature &&
bstream.peekNumber(4) !== zCentralFileHeaderSignature) {
while (bstream.peekNumber(4) !== LOCAL_FILE_HEADER_SIG &&
bstream.peekNumber(4) !== ARCHIVE_EXTRA_DATA_SIG &&
bstream.peekNumber(4) !== CENTRAL_FILE_HEADER_SIG) {
numBytesSeeked++;
bstream.readBytes(1);
}
@ -143,7 +137,7 @@ class ZipLocalFile {
// From the PKZIP App Note: "The signature value 0x08074b50 is also used by some ZIP
// implementations as a marker for the Data Descriptor record".
if (maybeDescriptorSig === zDataDescriptorSignature) {
if (maybeDescriptorSig === DATA_DESCRIPTOR_SIG) {
if (maybeCompressedSize === (numBytesSeeked - 16)) {
foundDataDescriptor = true;
descriptorSize = 16;
@ -606,7 +600,7 @@ function archiveUnzip() {
let bstream = bytestream.tee();
// loop until we don't see any more local files or we find a data descriptor.
while (bstream.peekNumber(4) == zLocalFileHeaderSignature) {
while (bstream.peekNumber(4) == LOCAL_FILE_HEADER_SIG) {
// Note that this could throw an error if the bstream overflows, which is caught in the
// message handler.
const oneLocalFile = new ZipLocalFile(bstream);
@ -636,7 +630,7 @@ function archiveUnzip() {
totalFilesInArchive = allLocalFiles.length;
// archive extra data record
if (bstream.peekNumber(4) == zArchiveExtraDataSignature) {
if (bstream.peekNumber(4) == ARCHIVE_EXTRA_DATA_SIG) {
if (logToConsole) {
info(' Found an Archive Extra Data Signature');
}
@ -649,13 +643,13 @@ function archiveUnzip() {
// central directory structure
// TODO: handle the rest of the structures (Zip64 stuff)
if (bstream.peekNumber(4) == zCentralFileHeaderSignature) {
if (bstream.peekNumber(4) == CENTRAL_FILE_HEADER_SIG) {
if (logToConsole) {
info(' Found a Central File Header');
}
// read all file headers
while (bstream.peekNumber(4) == zCentralFileHeaderSignature) {
while (bstream.peekNumber(4) == CENTRAL_FILE_HEADER_SIG) {
bstream.readNumber(4); // signature
const cdfh = {
versionMadeBy: bstream.readNumber(2),
@ -688,7 +682,7 @@ function archiveUnzip() {
}
// digital signature
if (bstream.peekNumber(4) == zDigitalSignatureSignature) {
if (bstream.peekNumber(4) == DIGITAL_SIGNATURE_SIG) {
if (logToConsole) {
info(' Found a Digital Signature');
}
@ -699,7 +693,7 @@ function archiveUnzip() {
}
let metadata = {};
if (bstream.peekNumber(4) == zEndOfCentralDirSignature) {
if (bstream.peekNumber(4) == END_OF_CENTRAL_DIR_SIG) {
bstream.readNumber(4); // signature
const eocds = {
numberOfThisDisk: bstream.readNumber(2),