mirror of
https://github.com/Ylianst/MeshAgent
synced 2025-12-06 00:13:33 +00:00
initial rev of streaming tar encoder
This commit is contained in:
Bryan Roe
260
modules/tar-encoder.js
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260
modules/tar-encoder.js
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@@ -0,0 +1,260 @@
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/*
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Copyright 2019 Intel Corporation
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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var readable = require('stream').Readable;
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function loadUstarHeader(path, offset)
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{
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var fd = require('fs').openSync(path, 'rb');
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var buffer = Buffer.alloc(512);
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var result = require('fs').readSync(fd, buffer, 0, 512, offset);
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require('fs').closeSync(fd);
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var v = 0;
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for (var i = 0; i < 512; ++i)
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{
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if (i >= 148 && i < 155)
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{
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v += 32;
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}
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else
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{
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v += buffer[i];
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}
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}
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if (parseInt(buffer.slice(148, 148 + 8).toString(), 8) != (new Uint32Array([v]))[0])
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{
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return (null);
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}
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else
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{
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return (buffer);
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}
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}
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function generateUstarHeader(path, basePath, uidtable, gidtable)
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{
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var ret = Buffer.alloc(512);
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var stats = require('fs').statSync(path);
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var name = process.platform == 'win32' ? path.split('\\').join('/') : path;
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if (basePath) { name = name.substring(basePath.endsWith('/') ? basePath.length : (basePath.length + 1)); }
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if (stats.isFile())
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{
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Buffer.from(stats.size.toString(8), 'binary').copy(ret, 124, 0, 12);
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Object.defineProperty(ret, 'isFile', { value: true });
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}
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else
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{
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Buffer.from('0').copy(ret, 124, 0, 12);
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Object.defineProperty(ret, 'isFile', { value: false });
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name += '/';
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}
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Buffer.from(name, 'binary').copy(ret, 0, 0, 100);
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ret[156] = stats.isFile() ? 48 : 53;
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Buffer.from((Date.parse(stats.mtime) / 1000).toString(8), 'binary').copy(ret, 136, 0, 12);
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Buffer.from('USTAR', 'binary').copy(ret, 257, 0, 5);
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if (process.platform == 'win32')
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{
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// Windows Platforms, set UID/GID to 0
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Buffer.from('0', 'binary').copy(ret, 108, 0, 8); // uid
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Buffer.from('0', 'binary').copy(ret, 116, 0, 8); // gid
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// Windows Platforms, set uname/gname to root/root
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Buffer.from('root', 'binary').copy(ret, 265, 0, 32);
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Buffer.from('root', 'binary').copy(ret, 297, 0, 32);
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// Windows Platforms, set mode to (S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH)
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var m = require('fs').CHMOD_MODES;
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Buffer.from((m.S_IRUSR | m.S_IWUSR | m.S_IRGRP | m.S_IWGRP | m.S_IROTH | m.S_IWOTH).toString(8), 'binary').copy(ret, 100, 0, 8);
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}
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else
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{
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// POSIX platforms, set the UID/GID
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Buffer.from(stats.uid.toString(8), 'binary').copy(ret, 108, 0, 8); // uid
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Buffer.from(stats.gid.toString(8), 'binary').copy(ret, 116, 0, 8); // gid
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if (!uidtable[stats.uid]) { uidtable[stats.uid] = require('user-sessions').getUsername(stats.uid); }
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if (!gidtable[stats.gid]) { gidtable[stats.gid] = require('user-sessions').getGroupname(stats.gid); }
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Buffer.from(uidtable[stats.uid], 'binary').copy(ret, 265, 0, 32);
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Buffer.from(gidtable[stats.gid], 'binary').copy(ret, 297, 0, 32);
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// Set Mode
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Buffer.from(stats.mode.toString(8), 'binary').copy(ret, 100, 0, 8);
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}
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var checksum = 0;
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for (var i = 0; i < 8; ++i)
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{
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ret[148 + i] = 32; // Blank out the checksum, so we can calculate the checksum, then write it back
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}
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for (var i = 0; i < 512; ++i)
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{
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checksum += ret[i];
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}
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Buffer.from(checksum.toString(8), 'binary').copy(ret, 148, 0, 8); // Write the checksum
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return (ret);
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}
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function encodeFiles(files, basePath)
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{
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var ret = new readable(
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{
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read: function read()
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{
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var bytesRead;
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var ok = true;
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if(this._fd == null)
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{
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if (this.files.length > 0)
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{
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var name = this.files.shift();
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var header = generateUstarHeader(name, this._basePath, this._uidTable, this._gidTable);
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if (header.isFile) { this._fd = require('fs').openSync(name, 'rb'); }
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ok = this.push(header);
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}
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else
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{
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this.pause();
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this.push(null);
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return;
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}
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}
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while(this._fd != null && ok)
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{
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bytesRead = require('fs').readSync(this._fd, this._buffer, 0, 512);
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this._buffer.fill(0, bytesRead, 512);
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if (bytesRead < 512)
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{
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require('fs').closeSync(this._fd);
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this._fd = null;
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}
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ok = this.push(this._buffer);
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}
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}
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});
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ret.files = files;
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ret._basePath = basePath;
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ret._fd = null;
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ret._buffer = Buffer.alloc(512);
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ret._uidTable = {};
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ret._gidTable = {};
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return (ret);
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}
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function expandFolderPaths(folderPath, recurse, arr)
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{
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var files = require('fs').readdirSync(folderPath);
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for(var f in files)
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{
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if(require('fs').statSync(folderPath + '/' + files[f]).isDirectory())
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{
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if (recurse)
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{
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arr.push(folderPath + '/' + files[f]);
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expandFolderPaths(folderPath + '/' + files[f], recurse, arr);
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}
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}
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else
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{
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arr.push(folderPath + '/' + files[f]);
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}
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}
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}
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function encodeFolder(folderPath, recurse)
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{
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var files = [];
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expandFolderPaths(folderPath, recurse, files);
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return (encodeFiles(files, folderPath));
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}
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function showHeader(path, offset)
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{
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do
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{
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var b = loadUstarHeader(path, offset);
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if (b == null) { break; }
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if (offset != null && isNaN(offset)) { process.exit();}
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console.log('-----------------------------');
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console.log('THIS Offset: ' + (offset == null ? 0 : offset));
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var mtime = parseInt(b.slice(136, 136 + 12).toString(), 8) * 1000;
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console.log('name: ' + b.slice(0, 100).toString());
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console.log('size: ' + parseInt(b.slice(124, 124 + 12).toString(), 8));
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console.log('mtime: ' + (new Date(mtime)).toString());
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console.log('type: ' + String.fromCharCode(b[156]));
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console.log('linkname: ' + b.slice(157, 257).toString());
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console.log('magic: ' + b.slice(257, 257 + 6).toString());
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console.log('version: ' + b.slice(263, 265).toString('hex'));
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console.log('uname: ' + b.slice(265, 265 + 32).toString());
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console.log('uid: ' + parseInt(b.slice(108, 108 + 8).toString(), 8));
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console.log('gname: ' + b.slice(297, 297 + 32).toString());
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console.log('gid: ' + parseInt(b.slice(116, 116 + 8).toString(), 8));
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console.log('prefix: ' + b.slice(345, 345 + 155).toString());
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console.log('mode: ' + b.slice(100, 100 + 8).toString());
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console.log('checksum: ' + parseInt(b.slice(148, 148 + 8).toString(), 8).toString());
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// Calculate Checksum
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for (var i = 0; i < 8; ++i)
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{
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b[148 + i] = 32;
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}
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var v = 0;
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for (var i = 0; i < 512; ++i)
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{
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v += b[i];
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}
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v = (new Uint32Array([v]))[0]
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console.log('Computed Checksum: ' + v.toString());
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console.log('');
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if (String.fromCharCode(b[156]) == '5')
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{
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if(offset == null)
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{
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offset = 512;
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}
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else
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{
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offset += 512;
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}
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}
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else
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{
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var filesize = parseInt(b.slice(124, 124 + 12).toString(), 8);
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var recordskip = Math.floor(filesize / 512);
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if (filesize % 512 != 0) { ++recordskip; }
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if (offset == null)
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{
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offset = recordskip * 512;
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}
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else
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{
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offset += (recordskip * 512);
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}
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offset += 512;
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}
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} while (offset != null);
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}
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module.exports = { encodeFolder: encodeFolder, encodeFiles: encodeFiles, showHeader: showHeader };
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