279 lines
No EOL
10 KiB
JavaScript
279 lines
No EOL
10 KiB
JavaScript
// parse a 512-byte header block to a data object, or vice-versa
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// encode returns `true` if a pax extended header is needed, because
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// the data could not be faithfully encoded in a simple header.
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// (Also, check header.needPax to see if it needs a pax header.)
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import { posix as pathModule } from 'node:path';
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import * as large from './large-numbers.js';
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import * as types from './types.js';
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export class Header {
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cksumValid = false;
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needPax = false;
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nullBlock = false;
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block;
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path;
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mode;
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uid;
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gid;
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size;
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cksum;
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#type = 'Unsupported';
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linkpath;
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uname;
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gname;
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devmaj = 0;
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devmin = 0;
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atime;
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ctime;
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mtime;
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charset;
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comment;
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constructor(data, off = 0, ex, gex) {
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if (Buffer.isBuffer(data)) {
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this.decode(data, off || 0, ex, gex);
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}
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else if (data) {
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this.#slurp(data);
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}
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}
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decode(buf, off, ex, gex) {
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if (!off) {
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off = 0;
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}
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if (!buf || !(buf.length >= off + 512)) {
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throw new Error('need 512 bytes for header');
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}
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this.path = decString(buf, off, 100);
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this.mode = decNumber(buf, off + 100, 8);
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this.uid = decNumber(buf, off + 108, 8);
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this.gid = decNumber(buf, off + 116, 8);
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this.size = decNumber(buf, off + 124, 12);
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this.mtime = decDate(buf, off + 136, 12);
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this.cksum = decNumber(buf, off + 148, 12);
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// if we have extended or global extended headers, apply them now
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// See https://github.com/npm/node-tar/pull/187
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// Apply global before local, so it overrides
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if (gex)
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this.#slurp(gex, true);
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if (ex)
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this.#slurp(ex);
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// old tar versions marked dirs as a file with a trailing /
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const t = decString(buf, off + 156, 1);
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if (types.isCode(t)) {
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this.#type = t || '0';
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}
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if (this.#type === '0' && this.path.slice(-1) === '/') {
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this.#type = '5';
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}
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// tar implementations sometimes incorrectly put the stat(dir).size
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// as the size in the tarball, even though Directory entries are
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// not able to have any body at all. In the very rare chance that
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// it actually DOES have a body, we weren't going to do anything with
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// it anyway, and it'll just be a warning about an invalid header.
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if (this.#type === '5') {
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this.size = 0;
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}
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this.linkpath = decString(buf, off + 157, 100);
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if (buf.subarray(off + 257, off + 265).toString() ===
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'ustar\u000000') {
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this.uname = decString(buf, off + 265, 32);
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this.gname = decString(buf, off + 297, 32);
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/* c8 ignore start */
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this.devmaj = decNumber(buf, off + 329, 8) ?? 0;
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this.devmin = decNumber(buf, off + 337, 8) ?? 0;
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/* c8 ignore stop */
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if (buf[off + 475] !== 0) {
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// definitely a prefix, definitely >130 chars.
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const prefix = decString(buf, off + 345, 155);
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this.path = prefix + '/' + this.path;
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}
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else {
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const prefix = decString(buf, off + 345, 130);
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if (prefix) {
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this.path = prefix + '/' + this.path;
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}
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this.atime = decDate(buf, off + 476, 12);
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this.ctime = decDate(buf, off + 488, 12);
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}
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}
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let sum = 8 * 0x20;
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for (let i = off; i < off + 148; i++) {
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sum += buf[i];
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}
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for (let i = off + 156; i < off + 512; i++) {
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sum += buf[i];
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}
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this.cksumValid = sum === this.cksum;
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if (this.cksum === undefined && sum === 8 * 0x20) {
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this.nullBlock = true;
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}
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}
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#slurp(ex, gex = false) {
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Object.assign(this, Object.fromEntries(Object.entries(ex).filter(([k, v]) => {
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// we slurp in everything except for the path attribute in
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// a global extended header, because that's weird. Also, any
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// null/undefined values are ignored.
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return !(v === null ||
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v === undefined ||
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(k === 'path' && gex) ||
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(k === 'linkpath' && gex) ||
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k === 'global');
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})));
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}
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encode(buf, off = 0) {
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if (!buf) {
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buf = this.block = Buffer.alloc(512);
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}
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if (this.#type === 'Unsupported') {
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this.#type = '0';
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}
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if (!(buf.length >= off + 512)) {
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throw new Error('need 512 bytes for header');
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}
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const prefixSize = this.ctime || this.atime ? 130 : 155;
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const split = splitPrefix(this.path || '', prefixSize);
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const path = split[0];
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const prefix = split[1];
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this.needPax = !!split[2];
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this.needPax = encString(buf, off, 100, path) || this.needPax;
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this.needPax =
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encNumber(buf, off + 100, 8, this.mode) || this.needPax;
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this.needPax =
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encNumber(buf, off + 108, 8, this.uid) || this.needPax;
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this.needPax =
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encNumber(buf, off + 116, 8, this.gid) || this.needPax;
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this.needPax =
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encNumber(buf, off + 124, 12, this.size) || this.needPax;
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this.needPax =
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encDate(buf, off + 136, 12, this.mtime) || this.needPax;
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buf[off + 156] = this.#type.charCodeAt(0);
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this.needPax =
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encString(buf, off + 157, 100, this.linkpath) || this.needPax;
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buf.write('ustar\u000000', off + 257, 8);
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this.needPax =
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encString(buf, off + 265, 32, this.uname) || this.needPax;
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this.needPax =
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encString(buf, off + 297, 32, this.gname) || this.needPax;
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this.needPax =
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encNumber(buf, off + 329, 8, this.devmaj) || this.needPax;
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this.needPax =
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encNumber(buf, off + 337, 8, this.devmin) || this.needPax;
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this.needPax =
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encString(buf, off + 345, prefixSize, prefix) || this.needPax;
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if (buf[off + 475] !== 0) {
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this.needPax =
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encString(buf, off + 345, 155, prefix) || this.needPax;
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}
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else {
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this.needPax =
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encString(buf, off + 345, 130, prefix) || this.needPax;
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this.needPax =
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encDate(buf, off + 476, 12, this.atime) || this.needPax;
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this.needPax =
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encDate(buf, off + 488, 12, this.ctime) || this.needPax;
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}
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let sum = 8 * 0x20;
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for (let i = off; i < off + 148; i++) {
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sum += buf[i];
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}
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for (let i = off + 156; i < off + 512; i++) {
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sum += buf[i];
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}
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this.cksum = sum;
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encNumber(buf, off + 148, 8, this.cksum);
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this.cksumValid = true;
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return this.needPax;
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}
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get type() {
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return (this.#type === 'Unsupported' ?
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this.#type
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: types.name.get(this.#type));
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}
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get typeKey() {
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return this.#type;
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}
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set type(type) {
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const c = String(types.code.get(type));
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if (types.isCode(c) || c === 'Unsupported') {
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this.#type = c;
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}
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else if (types.isCode(type)) {
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this.#type = type;
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}
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else {
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throw new TypeError('invalid entry type: ' + type);
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}
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}
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}
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const splitPrefix = (p, prefixSize) => {
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const pathSize = 100;
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let pp = p;
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let prefix = '';
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let ret = undefined;
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const root = pathModule.parse(p).root || '.';
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if (Buffer.byteLength(pp) < pathSize) {
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ret = [pp, prefix, false];
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}
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else {
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// first set prefix to the dir, and path to the base
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prefix = pathModule.dirname(pp);
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pp = pathModule.basename(pp);
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do {
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if (Buffer.byteLength(pp) <= pathSize &&
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Buffer.byteLength(prefix) <= prefixSize) {
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// both fit!
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ret = [pp, prefix, false];
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}
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else if (Buffer.byteLength(pp) > pathSize &&
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Buffer.byteLength(prefix) <= prefixSize) {
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// prefix fits in prefix, but path doesn't fit in path
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ret = [pp.slice(0, pathSize - 1), prefix, true];
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}
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else {
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// make path take a bit from prefix
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pp = pathModule.join(pathModule.basename(prefix), pp);
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prefix = pathModule.dirname(prefix);
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}
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} while (prefix !== root && ret === undefined);
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// at this point, found no resolution, just truncate
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if (!ret) {
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ret = [p.slice(0, pathSize - 1), '', true];
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}
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}
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return ret;
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};
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const decString = (buf, off, size) => buf
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.subarray(off, off + size)
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.toString('utf8')
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.replace(/\0.*/, '');
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const decDate = (buf, off, size) => numToDate(decNumber(buf, off, size));
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const numToDate = (num) => num === undefined ? undefined : new Date(num * 1000);
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const decNumber = (buf, off, size) => Number(buf[off]) & 0x80 ?
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large.parse(buf.subarray(off, off + size))
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: decSmallNumber(buf, off, size);
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const nanUndef = (value) => (isNaN(value) ? undefined : value);
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const decSmallNumber = (buf, off, size) => nanUndef(parseInt(buf
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.subarray(off, off + size)
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.toString('utf8')
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.replace(/\0.*$/, '')
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.trim(), 8));
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// the maximum encodable as a null-terminated octal, by field size
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const MAXNUM = {
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12: 0o77777777777,
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8: 0o7777777,
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};
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const encNumber = (buf, off, size, num) => num === undefined ? false
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: num > MAXNUM[size] || num < 0 ?
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(large.encode(num, buf.subarray(off, off + size)), true)
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: (encSmallNumber(buf, off, size, num), false);
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const encSmallNumber = (buf, off, size, num) => buf.write(octalString(num, size), off, size, 'ascii');
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const octalString = (num, size) => padOctal(Math.floor(num).toString(8), size);
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const padOctal = (str, size) => (str.length === size - 1 ?
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str
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: new Array(size - str.length - 1).join('0') + str + ' ') + '\0';
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const encDate = (buf, off, size, date) => date === undefined ? false : (encNumber(buf, off, size, date.getTime() / 1000));
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// enough to fill the longest string we've got
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const NULLS = new Array(156).join('\0');
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// pad with nulls, return true if it's longer or non-ascii
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const encString = (buf, off, size, str) => str === undefined ? false : ((buf.write(str + NULLS, off, size, 'utf8'),
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str.length !== Buffer.byteLength(str) || str.length > size));
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//# sourceMappingURL=header.js.map
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