Get rid of jszip and replace it with a custom library
This commit is contained in:
Jaiwanth
@@ -1,17 +1,278 @@
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/*Not to be reviewed now*/
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// class fileCheckSum {
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// protected CRC32: number;
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// public table: any[];
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// constructor() {
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// this.CRC32 = -1
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// }
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/* global ReadableStream */
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// protected append(data: any[]) {
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// let crc = this.CRC32 | 0;
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// const table = this.table;
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// for (let offset = 0, len = data.length | 0; offset < len; offset++) {
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// crc = (crc >>> 8) ^ table[(crc ^ data[offset]) & 0xFF]
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// }
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// this.CRC32 = crc
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// }
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// }
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type TypedArray =
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| Int8Array
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| Uint8Array
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| Int16Array
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| Uint16Array
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| Int32Array
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| Uint32Array
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| Uint8ClampedArray
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| Float32Array
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| Float64Array;
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/**
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* 32-bit cyclic redundancy check, or CRC-32 - checksum
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*/
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class Crc32 {
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crc: number;
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table: any;
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constructor() {
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this.crc = -1;
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this.table = (() => {
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let i
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let j
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let t;
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const table = [];
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for (i = 0; i < 256; i++) {
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t = i;
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for (j = 0; j < 8; j++) {
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t = (t & 1)
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? (t >>> 1) ^ 0xEDB88320
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: t >>> 1;
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}
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table[i] = t;
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}
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return table
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})()
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}
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append(data: TypedArray) {
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let crc = this.crc | 0;
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const table = this.table;
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for (let offset = 0, len = data.length | 0; offset < len; offset++) {
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crc = (crc >>> 8) ^ table[(crc ^ data[offset]) & 0xFF];
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}
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this.crc = crc;
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}
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get() {
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return ~this.crc;
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}
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}
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type DataHelper = {
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array: Uint8Array,
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view: DataView,
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}
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const getDataHelper = (byteLength: number): DataHelper => {
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const uint8 = new Uint8Array(byteLength)
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return {
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array: uint8,
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view: new DataView(uint8.buffer),
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};
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}
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type FileLike = File & {
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directory: string,
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comment: string,
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stream(): ReadableStream,
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}
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type ZipObj = {
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crc?: Crc32,
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uncompressedLength: number,
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compressedLength: number,
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ctrl: ReadableStreamDefaultController,
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writeFooter: Function,
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writeHeader: Function,
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reader?: ReadableStreamDefaultReader,
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offset: number
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header?: DataHelper,
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fileLike: FileLike,
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level: number,
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directory: boolean,
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}
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const pump = (zipObj: ZipObj) => zipObj.reader ? zipObj.reader.read().then(chunk => {
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if (zipObj.crc) {
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if (chunk.done) return zipObj.writeFooter();
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const outputData = chunk.value;
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zipObj.crc.append(outputData);
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zipObj.uncompressedLength += outputData.length;
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zipObj.compressedLength += outputData.length;
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zipObj.ctrl.enqueue(outputData);
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} else {
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throw new Error('Missing zipObj.crc');
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}
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}) : undefined;
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export default function ZIP(underlyingSource: UnderlyingSource) {
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const files = Object.create(null);
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const filenames: string[] = [];
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const encoder = new TextEncoder();
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let offset = 0;
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let activeZipIndex = 0;
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let ctrl: ReadableStreamDefaultController;
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let activeZipObject: ZipObj;
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let closed: boolean;
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function next() {
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activeZipIndex++;
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activeZipObject = files[filenames[activeZipIndex]];
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if (activeZipObject) processNextChunk();
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else if (closed) closeZip();
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}
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const zipWriter: ReadableStreamDefaultController = {
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desiredSize: null,
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error(err) {
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console.error(err)
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},
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enqueue(fileLike: FileLike) {
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if (closed) {
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throw new TypeError(
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"Cannot enqueue a chunk into a readable stream that is closed or has been requested to be closed",
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);
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}
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let name = fileLike.name.trim();
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const date = new Date(typeof fileLike.lastModified === 'undefined' ? Date.now() : fileLike.lastModified);
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if (fileLike.directory && !name.endsWith('/')) name += '/';
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if (files[name]) throw new Error('File already exists.');
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const nameBuf = encoder.encode(name);
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filenames.push(name);
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const zipObject: ZipObj = files[name] = {
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level: 0,
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ctrl,
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directory: !!fileLike.directory,
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nameBuf,
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comment: encoder.encode(fileLike.comment || ''),
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compressedLength: 0,
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uncompressedLength: 0,
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offset,
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writeHeader() {
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const header = getDataHelper(26)
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const data = getDataHelper(30 + nameBuf.length)
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zipObject.offset = offset;
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zipObject.header = header;
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if (zipObject.level !== 0 && !zipObject.directory) {
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header.view.setUint16(4, 0x0800);
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}
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header.view.setUint32(0, 0x14000808);
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header.view.setUint16(
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6,
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(((date.getHours() << 6) | date.getMinutes()) << 5) | (date.getSeconds() / 2),
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true,
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);
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header.view.setUint16(
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8,
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((((date.getFullYear() - 1980) << 4) | (date.getMonth() + 1)) << 5) |
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date.getDate(),
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true,
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);
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header.view.setUint16(22, nameBuf.length, true);
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data.view.setUint32(0, 0x504b0304);
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data.array.set(header.array, 4);
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data.array.set(nameBuf, 30);
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offset += data.array.length;
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ctrl.enqueue(data.array);
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},
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writeFooter() {
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const footer = getDataHelper(16);
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footer.view.setUint32(0, 0x504b0708);
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if (zipObject.crc && zipObject.header) {
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zipObject.header.view.setUint32(10, zipObject.crc.get(), true);
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zipObject.header.view.setUint32(14, zipObject.compressedLength, true);
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zipObject.header.view.setUint32(18, zipObject.uncompressedLength, true);
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footer.view.setUint32(4, zipObject.crc.get(), true);
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footer.view.setUint32(8, zipObject.compressedLength, true);
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footer.view.setUint32(12, zipObject.uncompressedLength, true);
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}
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ctrl.enqueue(footer.array);
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offset += zipObject.compressedLength + 16;
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next()
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},
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fileLike,
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}
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if (!activeZipObject) {
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activeZipObject = zipObject;
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processNextChunk();
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}
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},
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close() {
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if (closed) {
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throw new TypeError(
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"Cannot close a readable stream that has already been requested to be closed",
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);
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}
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if (!activeZipObject) closeZip();
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closed = true;
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},
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}
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function closeZip() {
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let length = 0;
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let index = 0
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let indexFilename;
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let file;
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for (indexFilename = 0; indexFilename < filenames.length; indexFilename++) {
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file = files[filenames[indexFilename]];
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length += 46 + file.nameBuf.length + file.comment.length;
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}
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const data = getDataHelper(length + 22)
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for (indexFilename = 0; indexFilename < filenames.length; indexFilename++) {
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file = files[filenames[indexFilename]];
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data.view.setUint32(index, 0x504b0102);
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data.view.setUint16(index + 4, 0x1400);
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data.array.set(file.header.array, index + 6);
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data.view.setUint16(index + 32, file.comment.length, true);
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if (file.directory) {
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data.view.setUint8(index + 38, 0x10);
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}
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data.view.setUint32(index + 42, file.offset, true);
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data.array.set(file.nameBuf, index + 46);
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data.array.set(file.comment, index + 46 + file.nameBuf.length);
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index += 46 + file.nameBuf.length + file.comment.length;
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}
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data.view.setUint32(index, 0x504b0506);
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data.view.setUint16(index + 8, filenames.length, true);
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data.view.setUint16(index + 10, filenames.length, true);
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data.view.setUint32(index + 12, length, true);
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data.view.setUint32(index + 16, offset, true);
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ctrl.enqueue(data.array);
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ctrl.close();
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}
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function processNextChunk() {
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if (!activeZipObject) return;
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if (activeZipObject.reader) return pump(activeZipObject);
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if (activeZipObject.fileLike.stream) {
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activeZipObject.crc = new Crc32();
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activeZipObject.reader = activeZipObject.fileLike.stream().getReader();
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activeZipObject.writeHeader();
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} else next();
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}
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return new ReadableStream({
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start: c => {
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ctrl = c;
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underlyingSource.start && Promise.resolve(underlyingSource.start(zipWriter));
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},
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pull() {
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return processNextChunk() || (
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underlyingSource.pull &&
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Promise.resolve(underlyingSource.pull(zipWriter))
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)
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},
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});
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}
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