300 lines
10 KiB
JavaScript
300 lines
10 KiB
JavaScript
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"use strict";
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Object.defineProperty(exports, "__esModule", {
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value: true
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});
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exports.default = parseDataUrl;
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const removeLeadingAndTrailingHTTPWhitespace = string => string.replace(/^[ \t\n\r]+/, "").replace(/[ \t\n\r]+$/, "");
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const removeTrailingHTTPWhitespace = string => string.replace(/[ \t\n\r]+$/, "");
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const isHTTPWhitespaceChar = char => char === " " || char === "\t" || char === "\n" || char === "\r";
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const solelyContainsHTTPTokenCodePoints = string => /^[-!#$%&'*+.^_`|~A-Za-z0-9]*$/.test(string);
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const soleyContainsHTTPQuotedStringTokenCodePoints = string => /^[\t\u0020-\u007E\u0080-\u00FF]*$/.test(string);
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const asciiLowercase = string => string.replace(/[A-Z]/g, l => l.toLowerCase());
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const collectAnHTTPQuotedString = (input, position) => {
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let value = "";
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// eslint-disable-next-line no-param-reassign
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position += 1;
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// eslint-disable-next-line no-constant-condition
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while (true) {
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while (position < input.length && input[position] !== '"' && input[position] !== "\\") {
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value += input[position];
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// eslint-disable-next-line no-param-reassign
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position += 1;
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}
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if (position >= input.length) {
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break;
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}
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const quoteOrBackslash = input[position];
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// eslint-disable-next-line no-param-reassign
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position += 1;
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if (quoteOrBackslash === "\\") {
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if (position >= input.length) {
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value += "\\";
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break;
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}
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value += input[position];
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// eslint-disable-next-line no-param-reassign
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position += 1;
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} else {
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break;
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}
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}
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return [value, position];
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};
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function isASCIIHex(c) {
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return c >= 0x30 && c <= 0x39 || c >= 0x41 && c <= 0x46 || c >= 0x61 && c <= 0x66;
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}
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function percentDecodeBytes(input) {
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const output = new Uint8Array(input.byteLength);
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let outputIndex = 0;
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for (let i = 0; i < input.byteLength; ++i) {
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const byte = input[i];
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if (byte !== 0x25) {
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output[outputIndex] = byte;
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} else if (byte === 0x25 && (!isASCIIHex(input[i + 1]) || !isASCIIHex(input[i + 2]))) {
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output[outputIndex] = byte;
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} else {
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output[outputIndex] = parseInt(String.fromCodePoint(input[i + 1], input[i + 2]), 16);
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i += 2;
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}
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outputIndex += 1;
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}
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return output.slice(0, outputIndex);
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}
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/**
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* A lookup table for atob(), which converts an ASCII character to the
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* corresponding six-bit number.
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*/
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const characters = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
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function atobLookup(chr) {
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const index = characters.indexOf(chr);
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// Throw exception if character is not in the lookup string; should not be hit in tests
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// eslint-disable-next-line no-undefined
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return index < 0 ? undefined : index;
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}
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/**
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* Implementation of atob() according to the HTML and Infra specs, except that
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* instead of throwing INVALID_CHARACTER_ERR we return null.
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*/
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function atob(input) {
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/* eslint-disable no-bitwise */
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// Web IDL requires DOMStrings to just be converted using ECMAScript
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// ToString, which in our case amounts to using a template literal.
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let data = `${input}`;
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// "Remove all ASCII whitespace from data."
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data = data.replace(/[ \t\n\f\r]/g, "");
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// "If data's length divides by 4 leaving no remainder, then: if data ends
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// with one or two U+003D (=) code points, then remove them from data."
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if (data.length % 4 === 0) {
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data = data.replace(/==?$/, "");
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}
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// "If data's length divides by 4 leaving a remainder of 1, then return
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// failure."
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//
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// "If data contains a code point that is not one of
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//
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// U+002B (+)
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// U+002F (/)
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// ASCII alphanumeric
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//
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// then return failure."
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if (data.length % 4 === 1 || /[^+/0-9A-Za-z]/.test(data)) {
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return null;
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}
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// "Let output be an empty byte sequence."
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let output = "";
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// "Let buffer be an empty buffer that can have bits appended to it."
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//
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// We append bits via left-shift and or. accumulatedBits is used to track
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// when we've gotten to 24 bits.
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let buffer = 0;
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let accumulatedBits = 0;
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// "Let position be a position variable for data, initially pointing at the
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// start of data."
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//
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// "While position does not point past the end of data:"
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for (let i = 0; i < data.length; i++) {
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// "Find the code point pointed to by position in the second column of
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// Table 1: The Base 64 Alphabet of RFC 4648. Let n be the number given in
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// the first cell of the same row.
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//
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// "Append to buffer the six bits corresponding to n, most significant bit
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// first."
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//
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// atobLookup() implements the table from RFC 4648.
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// eslint-disable-next-line no-bitwise
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buffer <<= 6;
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// eslint-disable-next-line no-bitwise
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buffer |= atobLookup(data[i]);
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accumulatedBits += 6;
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// "If buffer has accumulated 24 bits, interpret them as three 8-bit
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// big-endian numbers. Append three bytes with values equal to those
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// numbers to output, in the same order, and then empty buffer."
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if (accumulatedBits === 24) {
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output += String.fromCharCode((buffer & 0xff0000) >> 16);
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output += String.fromCharCode((buffer & 0xff00) >> 8);
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output += String.fromCharCode(buffer & 0xff);
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accumulatedBits = 0;
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buffer = 0;
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}
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// "Advance position by 1."
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}
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// "If buffer is not empty, it contains either 12 or 18 bits. If it contains
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// 12 bits, then discard the last four and interpret the remaining eight as
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// an 8-bit big-endian number. If it contains 18 bits, then discard the last
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// two and interpret the remaining 16 as two 8-bit big-endian numbers. Append
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// the one or two bytes with values equal to those one or two numbers to
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// output, in the same order."
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if (accumulatedBits === 12) {
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buffer >>= 4;
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output += String.fromCharCode(buffer);
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} else if (accumulatedBits === 18) {
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buffer >>= 2;
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output += String.fromCharCode((buffer & 0xff00) >> 8);
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output += String.fromCharCode(buffer & 0xff);
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}
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/* eslint-enable no-bitwise */
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// "Return output."
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return output;
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}
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function parseDataUrl(stringInput) {
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let parsedUrl;
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try {
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parsedUrl = new URL(stringInput);
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} catch (error) {
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return null;
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}
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if (parsedUrl.protocol !== "data:") {
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return null;
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}
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parsedUrl.hash = "";
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// `5` is value of `'data:'.length`
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const input = parsedUrl.toString().substring(5);
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let position = 0;
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let mediaType = "";
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while (position < input.length && input[position] !== ",") {
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mediaType += input[position];
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position += 1;
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}
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mediaType = mediaType.replace(/^[ \t\n\f\r]+/, "").replace(/[ \t\n\f\r]+$/, "");
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if (position === input.length) {
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return null;
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}
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position += 1;
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const encodedBody = input.substring(position);
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let body = Buffer.from(percentDecodeBytes(Buffer.from(encodedBody, "utf-8")));
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// Can't use /i regexp flag because it isn't restricted to ASCII.
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const mimeTypeBase64MatchResult = /(.*); *[Bb][Aa][Ss][Ee]64$/.exec(mediaType);
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if (mimeTypeBase64MatchResult) {
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const stringBody = body.toString("binary");
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const asString = atob(stringBody);
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if (asString === null) {
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return null;
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}
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body = Buffer.from(asString, "binary");
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[, mediaType] = mimeTypeBase64MatchResult;
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}
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if (mediaType.startsWith(";")) {
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mediaType = `text/plain ${mediaType}`;
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}
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const result = {
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// eslint-disable-next-line no-undefined
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type: undefined,
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// eslint-disable-next-line no-undefined
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subtype: undefined,
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parameters: new Map(),
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isBase64: Boolean(mimeTypeBase64MatchResult),
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body
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};
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if (!mediaType) {
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return result;
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}
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const inputMediaType = removeLeadingAndTrailingHTTPWhitespace(mediaType);
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let positionMediaType = 0;
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let type = "";
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while (positionMediaType < inputMediaType.length && inputMediaType[positionMediaType] !== "/") {
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type += inputMediaType[positionMediaType];
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positionMediaType += 1;
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}
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if (type.length === 0 || !solelyContainsHTTPTokenCodePoints(type)) {
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return result;
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}
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if (positionMediaType >= inputMediaType.length) {
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return result;
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}
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// Skips past "/"
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positionMediaType += 1;
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let subtype = "";
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while (positionMediaType < inputMediaType.length && inputMediaType[positionMediaType] !== ";") {
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subtype += inputMediaType[positionMediaType];
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positionMediaType += 1;
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}
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subtype = removeTrailingHTTPWhitespace(subtype);
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if (subtype.length === 0 || !solelyContainsHTTPTokenCodePoints(subtype)) {
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return result;
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}
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result.type = asciiLowercase(type);
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result.subtype = asciiLowercase(subtype);
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while (positionMediaType < inputMediaType.length) {
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// Skip past ";"
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positionMediaType += 1;
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while (isHTTPWhitespaceChar(inputMediaType[positionMediaType])) {
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positionMediaType += 1;
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}
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let parameterName = "";
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while (positionMediaType < inputMediaType.length && inputMediaType[positionMediaType] !== ";" && inputMediaType[positionMediaType] !== "=") {
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parameterName += inputMediaType[positionMediaType];
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positionMediaType += 1;
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}
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parameterName = asciiLowercase(parameterName);
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if (positionMediaType < inputMediaType.length) {
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if (inputMediaType[positionMediaType] === ";") {
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// eslint-disable-next-line no-continue
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continue;
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}
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// Skip past "="
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positionMediaType += 1;
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}
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let parameterValue = "";
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if (inputMediaType[positionMediaType] === '"') {
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[parameterValue, positionMediaType] = collectAnHTTPQuotedString(inputMediaType, positionMediaType);
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while (positionMediaType < inputMediaType.length && inputMediaType[positionMediaType] !== ";") {
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positionMediaType += 1;
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}
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} else {
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while (positionMediaType < inputMediaType.length && inputMediaType[positionMediaType] !== ";") {
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parameterValue += inputMediaType[positionMediaType];
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positionMediaType += 1;
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}
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parameterValue = removeTrailingHTTPWhitespace(parameterValue);
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if (parameterValue === "") {
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// eslint-disable-next-line no-continue
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continue;
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}
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}
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if (parameterName.length > 0 && solelyContainsHTTPTokenCodePoints(parameterName) && soleyContainsHTTPQuotedStringTokenCodePoints(parameterValue) && !result.parameters.has(parameterName)) {
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result.parameters.set(parameterName, parameterValue);
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}
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}
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return result;
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}
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