mirror of
https://github.com/gchq/CyberChef.git
synced 2025-04-22 15:56:16 -04:00
Added parsing of headers.
This commit is contained in:
mshwed
mshwed
parent
c3994aa8e3
commit
7f97afd3e0
3 changed files with 172 additions and 78 deletions
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@ -7,8 +7,9 @@
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import Operation from "../Operation";
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import OperationError from "../errors/OperationError";
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import Utils from "../Utils";
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import {fromHex} from "../lib/Hex.mjs";
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import { fromHex } from "../lib/Hex.mjs";
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import { fromBase64 } from "../lib/Base64";
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import cptable from "../vendor/js-codepage/cptable.js";
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/**
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* MIME Decoding operation
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@ -23,24 +24,11 @@ class MIMEDecoding extends Operation {
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this.name = "MIME Decoding";
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this.module = "Default";
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this.description = "";
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this.infoURL = "";
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this.description = "Enables the decoding of MIME message header extensions for non-ASCII text";
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this.infoURL = "https://tools.ietf.org/html/rfc2047";
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this.inputType = "byteArray";
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this.outputType = "string";
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this.args = [
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/* Example arguments. See the project wiki for full details.
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{
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name: "First arg",
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type: "string",
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value: "Don't Panic"
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},
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{
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name: "Second arg",
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type: "number",
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value: 42
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}
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*/
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];
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this.args = [];
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}
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/**
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@ -49,73 +37,135 @@ class MIMEDecoding extends Operation {
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* @returns {string}
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*/
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run(input, args) {
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const mimeEncodedText = Utils.byteArrayToUtf8(input);
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const encodedHeaders = mimeEncodedText.replace(/\r\n/g, "\n");
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let mimeEncodedText = Utils.byteArrayToUtf8(input)
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const decodedHeader = this.decodeHeaders(encodedHeaders);
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let parsedString = "";
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let currentPos = 0;
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let pastPosition = 0;
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while (currentPos >= 0) {
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// Find starting text
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currentPos = mimeEncodedText.indexOf("=?", pastPosition);
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console.log('CURRENT POSITION', currentPos);
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if (currentPos < 0) break;
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// Add existing unparsed string
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let fillerText = mimeEncodedText.substring(pastPosition, currentPos);
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console.log("PROCESSING RANGE", pastPosition, ' ' ,currentPos)
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console.log('FILLER TEXT: ', fillerText);
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if (fillerText.indexOf('\r') > 0) console.log('CR detected', fillerText.indexOf('\r'));
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if (fillerText.indexOf('\n') > 0) console.log('LF detected', fillerText.indexOf('\n'));
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if (fillerText.indexOf('\r\n') > 0) console.log('CRLF detected', fillerText.indexOf('\r\n'));
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if (fillerText.indexOf('\x20') > 0) console.log('SPACE detected', fillerText.indexOf('\x20'));
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if (fillerText.indexOf('\n\x20') > 0) console.log('newline SPACE detected', fillerText.indexOf('\x20'));
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if (fillerText !== '\r\n')
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parsedString += fillerText
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pastPosition = currentPos;
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// find ending text
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currentPos = mimeEncodedText.indexOf("?=", pastPosition);
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// Process block
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let encodedTextBlock = mimeEncodedText.substring(pastPosition + 2, currentPos);
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pastPosition = currentPos + 2;
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parsedString += this.parseEncodedWord(encodedTextBlock);
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}
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return parsedString;
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throw new OperationError("Test");
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return decodedHeader;
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}
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parseEncodedWord(encodedWord) {
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let [charset, encoding, encodedBlock] = encodedWord.split('?');
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/**
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* Decode MIME header strings
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*
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* @param headerString
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*/
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decodeHeaders(headerString) {
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// No encoded words detected
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let i = headerString.indexOf("=?");
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if (i === -1) return headerString;
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console.log('CURRENT BLOCK TO PROCESS', encodedBlock);
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console.log('CURRENT CHARSET', charset);
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let decodedHeaders = headerString.slice(0, i);
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let header = headerString.slice(i);
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let encodedText = '';
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if (encoding.toLowerCase() === 'b') {
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encodedText = fromBase64(encodedBlock);
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} else {
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encodedText = encodedBlock;
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let encodedChars = encodedText.indexOf("=");
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if (encodedChars > 0) {
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let extractedHex = encodedText.substring(encodedChars + 1, encodedChars + 3);
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console.log("EXTRACTED HEX", extractedHex)
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encodedText = encodedText.replace(`=${extractedHex}`, Utils.byteArrayToChars(fromHex(`=${extractedHex}`)))
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let isBetweenWords = false;
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let start, cur, charset, encoding, j, end, text;
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while (header.length > -1) {
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start = header.indexOf("=?");
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if (start === -1) break;
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cur = start + "=?".length;
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i = header.slice(cur).indexOf("?");
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if (i === -1) break;
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charset = header.slice(cur, cur + i);
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cur += i + "?".length;
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if (header.length < cur + "Q??=".length) break;
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encoding = header[cur];
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cur += 1;
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if (header[cur] !== "?") break;
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cur += 1;
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j = header.slice(cur).indexOf("?=");
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if (j === -1) break;
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text = header.slice(cur, cur + j);
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end = cur + j + "?=".length;
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if (encoding.toLowerCase() === "b") {
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text = fromBase64(text);
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} else if (encoding.toLowerCase() === "q") {
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text = this.parseQEncodedWord(text);
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} else {
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isBetweenWords = false;
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decodedHeaders += header.slice(0, start + 2);
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header = header.slice(start + 2);
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}
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encodedText = encodedText.replace("_", " ");
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if (start > 0 && (!isBetweenWords || header.slice(0, start).search(/\S/g) > -1)) {
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decodedHeaders += header.slice(0, start);
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}
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decodedHeaders += this.convertFromCharset(charset, text);
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header = header.slice(end);
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isBetweenWords = true;
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}
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return encodedText;
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if (header.length > 0) {
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decodedHeaders += header;
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}
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return decodedHeaders;
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}
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/**
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* Converts decoded text for supported charsets.
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* Supports UTF-8, US-ASCII, ISO-8859-*
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*
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* @param encodedWord
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*/
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convertFromCharset(charset, encodedText) {
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charset = charset.toLowerCase();
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const parsedCharset = charset.split("-");
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if (parsedCharset.length === 2 && parsedCharset[0] === "utf" && charset === "utf-8") {
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return cptable.utils.decode(65001, encodedText);
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} else if (parsedCharset.length === 2 && charset === "us-ascii") {
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return cptable.utils.decode(20127, encodedText);
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} else if (parsedCharset.length === 3 && parsedCharset[0] === "iso" && parsedCharset[1] === "8859") {
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const isoCharset = parseInt(parsedCharset[2], 10);
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if (isoCharset >= 1 && isoCharset <= 16) {
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return cptable.utils.decode(28590 + isoCharset, encodedText);
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}
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}
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throw new OperationError("Unhandled Charset");
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}
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/**
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* Parses a Q encoded word
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*
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* @param encodedWord
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*/
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parseQEncodedWord(encodedWord) {
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let decodedWord = "";
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for (let i = 0; i < encodedWord.length; i++) {
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if (encodedWord[i] === "_") {
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decodedWord += " ";
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// Parse hex encoding
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} else if (encodedWord[i] === "=") {
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if ((i + 2) >= encodedWord.length) throw new OperationError("Incorrectly Encoded Word");
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const decodedHex = Utils.byteArrayToChars(fromHex(encodedWord.substring(i + 1, i + 3)));
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decodedWord += decodedHex;
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i += 2;
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} else if (
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(encodedWord[i].charCodeAt(0) >= " ".charCodeAt(0) && encodedWord[i].charCodeAt(0) <= "~".charCodeAt(0)) ||
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encodedWord[i] === "\n" ||
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encodedWord[i] === "\r" ||
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encodedWord[i] === "\t") {
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decodedWord += encodedWord[i];
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} else {
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throw new OperationError("Incorrectly Encoded Word");
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}
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}
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return decodedWord;
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}
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}
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export default MIMEDecoding;
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