120 lines
3.9 KiB
JavaScript
120 lines
3.9 KiB
JavaScript
var Buffer = require('buffer').Buffer;
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var semver = require('semver');
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if (semver.gte(process.version, '6.0.0')) {
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function allocateAsciiBuffer(length) {
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return Buffer.alloc(length, 'ascii');
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}
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} else {
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function allocateAsciiBuffer(length) {
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return new Buffer(length, 'ascii');
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}
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}
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function encode(str) {
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var b = allocateAsciiBuffer(str.length * 2);
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for (var i = 0, bi = 0; i < str.length; i++) {
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// Note that we can't simply convert a UTF-8 string to Base64 because
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// UTF-8 uses a different encoding. In modified UTF-7, all characters
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// are represented by their two byte Unicode ID.
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var c = str.charCodeAt(i);
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// Upper 8 bits shifted into lower 8 bits so that they fit into 1 byte.
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b[bi++] = c >> 8;
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// Lower 8 bits. Cut off the upper 8 bits so that they fit into 1 byte.
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b[bi++] = c & 0xFF;
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}
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// Modified Base64 uses , instead of / and omits trailing =.
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return b.toString('base64').replace(/=+$/, '');
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}
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if (semver.gte(process.version, '6.0.0')) {
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function allocateBase64Buffer(str) {
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return Buffer.from(str, 'base64');
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}
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} else {
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function allocateBase64Buffer(str) {
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return new Buffer(str, 'base64');
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}
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}
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function decode(str) {
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var b = allocateBase64Buffer(str);
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var r = [];
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for (var i = 0; i < b.length;) {
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// Calculate charcode from two adjacent bytes.
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r.push(String.fromCharCode(b[i++] << 8 | b[i++]));
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}
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return r.join('');
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}
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// Escape RegEx from http://simonwillison.net/2006/Jan/20/escape/
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function escape(chars) {
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return chars.replace(/[-[\]{}()*+?.,\\^$|#\s]/g, "\\$&");
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}
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// Character classes defined by RFC 2152.
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var setD = "A-Za-z0-9" + escape("'(),-./:?");
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var setO = escape("!\"#$%&*;<=>@[]^_'{|}");
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var setW = escape(" \r\n\t");
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// Stores compiled regexes for various replacement pattern.
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var regexes = {};
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var regexAll = new RegExp("[^" + setW + setD + setO + "]+", 'g');
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exports.imap = {};
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// RFC 2152 UTF-7 encoding.
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exports.encode = function(str, mask) {
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// Generate a RegExp object from the string of mask characters.
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if (!mask) {
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mask = '';
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}
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if (!regexes[mask]) {
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regexes[mask] = new RegExp("[^" + setD + escape(mask) + "]+", 'g');
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}
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// We replace subsequent disallowed chars with their escape sequence.
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return str.replace(regexes[mask], function(chunk) {
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// + is represented by an empty sequence +-, otherwise call encode().
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return '+' + (chunk === '+' ? '' : encode(chunk)) + '-';
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});
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};
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// RFC 2152 UTF-7 encoding with all optionals.
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exports.encodeAll = function(str) {
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// We replace subsequent disallowed chars with their escape sequence.
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return str.replace(regexAll, function(chunk) {
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// + is represented by an empty sequence +-, otherwise call encode().
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return '+' + (chunk === '+' ? '' : encode(chunk)) + '-';
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});
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};
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// RFC 3501, section 5.1.3 UTF-7 encoding.
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exports.imap.encode = function(str) {
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// All printable ASCII chars except for & must be represented by themselves.
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// We replace subsequent non-representable chars with their escape sequence.
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return str.replace(/&/g, '&-').replace(/[^\x20-\x7e]+/g, function(chunk) {
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// & is represented by an empty sequence &-, otherwise call encode().
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chunk = (chunk === '&' ? '' : encode(chunk)).replace(/\//g, ',');
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return '&' + chunk + '-';
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});
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};
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// RFC 2152 UTF-7 decoding.
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exports.decode = function(str) {
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return str.replace(/\+([A-Za-z0-9\/]*)-?/gi, function(_, chunk) {
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// &- represents &.
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if (chunk === '') return '+';
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return decode(chunk);
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});
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};
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// RFC 3501, section 5.1.3 UTF-7 decoding.
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exports.imap.decode = function(str) {
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return str.replace(/&([^-]*)-/g, function(_, chunk) {
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// &- represents &.
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if (chunk === '') return '&';
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return decode(chunk.replace(/,/g, '/'));
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});
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};
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