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290 lines
9.1 KiB
290 lines
9.1 KiB
"use strict";
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var Buffer = require("safer-buffer").Buffer;
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// UTF-7 codec, according to https://tools.ietf.org/html/rfc2152
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// See also below a UTF-7-IMAP codec, according to http://tools.ietf.org/html/rfc3501#section-5.1.3
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exports.utf7 = Utf7Codec;
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exports.unicode11utf7 = 'utf7'; // Alias UNICODE-1-1-UTF-7
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function Utf7Codec(codecOptions, iconv) {
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this.iconv = iconv;
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};
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Utf7Codec.prototype.encoder = Utf7Encoder;
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Utf7Codec.prototype.decoder = Utf7Decoder;
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Utf7Codec.prototype.bomAware = true;
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// -- Encoding
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var nonDirectChars = /[^A-Za-z0-9'\(\),-\.\/:\? \n\r\t]+/g;
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function Utf7Encoder(options, codec) {
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this.iconv = codec.iconv;
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}
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Utf7Encoder.prototype.write = function(str) {
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// Naive implementation.
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// Non-direct chars are encoded as "+<base64>-"; single "+" char is encoded as "+-".
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return Buffer.from(str.replace(nonDirectChars, function(chunk) {
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return "+" + (chunk === '+' ? '' :
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this.iconv.encode(chunk, 'utf16-be').toString('base64').replace(/=+$/, ''))
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+ "-";
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}.bind(this)));
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}
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Utf7Encoder.prototype.end = function() {
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}
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// -- Decoding
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function Utf7Decoder(options, codec) {
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this.iconv = codec.iconv;
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this.inBase64 = false;
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this.base64Accum = '';
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}
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var base64Regex = /[A-Za-z0-9\/+]/;
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var base64Chars = [];
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for (var i = 0; i < 256; i++)
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base64Chars[i] = base64Regex.test(String.fromCharCode(i));
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var plusChar = '+'.charCodeAt(0),
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minusChar = '-'.charCodeAt(0),
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andChar = '&'.charCodeAt(0);
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Utf7Decoder.prototype.write = function(buf) {
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var res = "", lastI = 0,
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inBase64 = this.inBase64,
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base64Accum = this.base64Accum;
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// The decoder is more involved as we must handle chunks in stream.
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for (var i = 0; i < buf.length; i++) {
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if (!inBase64) { // We're in direct mode.
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// Write direct chars until '+'
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if (buf[i] == plusChar) {
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res += this.iconv.decode(buf.slice(lastI, i), "ascii"); // Write direct chars.
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lastI = i+1;
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inBase64 = true;
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}
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} else { // We decode base64.
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if (!base64Chars[buf[i]]) { // Base64 ended.
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if (i == lastI && buf[i] == minusChar) {// "+-" -> "+"
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res += "+";
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} else {
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var b64str = base64Accum + this.iconv.decode(buf.slice(lastI, i), "ascii");
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res += this.iconv.decode(Buffer.from(b64str, 'base64'), "utf16-be");
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}
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if (buf[i] != minusChar) // Minus is absorbed after base64.
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i--;
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lastI = i+1;
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inBase64 = false;
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base64Accum = '';
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}
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}
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}
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if (!inBase64) {
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res += this.iconv.decode(buf.slice(lastI), "ascii"); // Write direct chars.
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} else {
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var b64str = base64Accum + this.iconv.decode(buf.slice(lastI), "ascii");
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var canBeDecoded = b64str.length - (b64str.length % 8); // Minimal chunk: 2 quads -> 2x3 bytes -> 3 chars.
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base64Accum = b64str.slice(canBeDecoded); // The rest will be decoded in future.
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b64str = b64str.slice(0, canBeDecoded);
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res += this.iconv.decode(Buffer.from(b64str, 'base64'), "utf16-be");
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}
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this.inBase64 = inBase64;
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this.base64Accum = base64Accum;
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return res;
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}
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Utf7Decoder.prototype.end = function() {
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var res = "";
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if (this.inBase64 && this.base64Accum.length > 0)
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res = this.iconv.decode(Buffer.from(this.base64Accum, 'base64'), "utf16-be");
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this.inBase64 = false;
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this.base64Accum = '';
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return res;
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}
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// UTF-7-IMAP codec.
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// RFC3501 Sec. 5.1.3 Modified UTF-7 (http://tools.ietf.org/html/rfc3501#section-5.1.3)
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// Differences:
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// * Base64 part is started by "&" instead of "+"
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// * Direct characters are 0x20-0x7E, except "&" (0x26)
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// * In Base64, "," is used instead of "/"
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// * Base64 must not be used to represent direct characters.
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// * No implicit shift back from Base64 (should always end with '-')
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// * String must end in non-shifted position.
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// * "-&" while in base64 is not allowed.
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exports.utf7imap = Utf7IMAPCodec;
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function Utf7IMAPCodec(codecOptions, iconv) {
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this.iconv = iconv;
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};
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Utf7IMAPCodec.prototype.encoder = Utf7IMAPEncoder;
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Utf7IMAPCodec.prototype.decoder = Utf7IMAPDecoder;
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Utf7IMAPCodec.prototype.bomAware = true;
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// -- Encoding
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function Utf7IMAPEncoder(options, codec) {
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this.iconv = codec.iconv;
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this.inBase64 = false;
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this.base64Accum = Buffer.alloc(6);
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this.base64AccumIdx = 0;
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}
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Utf7IMAPEncoder.prototype.write = function(str) {
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var inBase64 = this.inBase64,
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base64Accum = this.base64Accum,
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base64AccumIdx = this.base64AccumIdx,
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buf = Buffer.alloc(str.length*5 + 10), bufIdx = 0;
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for (var i = 0; i < str.length; i++) {
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var uChar = str.charCodeAt(i);
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if (0x20 <= uChar && uChar <= 0x7E) { // Direct character or '&'.
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if (inBase64) {
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if (base64AccumIdx > 0) {
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bufIdx += buf.write(base64Accum.slice(0, base64AccumIdx).toString('base64').replace(/\//g, ',').replace(/=+$/, ''), bufIdx);
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base64AccumIdx = 0;
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}
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buf[bufIdx++] = minusChar; // Write '-', then go to direct mode.
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inBase64 = false;
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}
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if (!inBase64) {
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buf[bufIdx++] = uChar; // Write direct character
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if (uChar === andChar) // Ampersand -> '&-'
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buf[bufIdx++] = minusChar;
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}
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} else { // Non-direct character
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if (!inBase64) {
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buf[bufIdx++] = andChar; // Write '&', then go to base64 mode.
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inBase64 = true;
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}
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if (inBase64) {
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base64Accum[base64AccumIdx++] = uChar >> 8;
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base64Accum[base64AccumIdx++] = uChar & 0xFF;
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if (base64AccumIdx == base64Accum.length) {
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bufIdx += buf.write(base64Accum.toString('base64').replace(/\//g, ','), bufIdx);
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base64AccumIdx = 0;
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}
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}
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}
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}
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this.inBase64 = inBase64;
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this.base64AccumIdx = base64AccumIdx;
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return buf.slice(0, bufIdx);
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}
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Utf7IMAPEncoder.prototype.end = function() {
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var buf = Buffer.alloc(10), bufIdx = 0;
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if (this.inBase64) {
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if (this.base64AccumIdx > 0) {
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bufIdx += buf.write(this.base64Accum.slice(0, this.base64AccumIdx).toString('base64').replace(/\//g, ',').replace(/=+$/, ''), bufIdx);
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this.base64AccumIdx = 0;
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}
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buf[bufIdx++] = minusChar; // Write '-', then go to direct mode.
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this.inBase64 = false;
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}
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return buf.slice(0, bufIdx);
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}
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// -- Decoding
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function Utf7IMAPDecoder(options, codec) {
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this.iconv = codec.iconv;
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this.inBase64 = false;
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this.base64Accum = '';
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}
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var base64IMAPChars = base64Chars.slice();
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base64IMAPChars[','.charCodeAt(0)] = true;
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Utf7IMAPDecoder.prototype.write = function(buf) {
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var res = "", lastI = 0,
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inBase64 = this.inBase64,
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base64Accum = this.base64Accum;
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// The decoder is more involved as we must handle chunks in stream.
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// It is forgiving, closer to standard UTF-7 (for example, '-' is optional at the end).
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for (var i = 0; i < buf.length; i++) {
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if (!inBase64) { // We're in direct mode.
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// Write direct chars until '&'
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if (buf[i] == andChar) {
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res += this.iconv.decode(buf.slice(lastI, i), "ascii"); // Write direct chars.
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lastI = i+1;
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inBase64 = true;
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}
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} else { // We decode base64.
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if (!base64IMAPChars[buf[i]]) { // Base64 ended.
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if (i == lastI && buf[i] == minusChar) { // "&-" -> "&"
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res += "&";
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} else {
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var b64str = base64Accum + this.iconv.decode(buf.slice(lastI, i), "ascii").replace(/,/g, '/');
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res += this.iconv.decode(Buffer.from(b64str, 'base64'), "utf16-be");
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}
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if (buf[i] != minusChar) // Minus may be absorbed after base64.
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i--;
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lastI = i+1;
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inBase64 = false;
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base64Accum = '';
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}
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}
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}
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if (!inBase64) {
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res += this.iconv.decode(buf.slice(lastI), "ascii"); // Write direct chars.
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} else {
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var b64str = base64Accum + this.iconv.decode(buf.slice(lastI), "ascii").replace(/,/g, '/');
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var canBeDecoded = b64str.length - (b64str.length % 8); // Minimal chunk: 2 quads -> 2x3 bytes -> 3 chars.
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base64Accum = b64str.slice(canBeDecoded); // The rest will be decoded in future.
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b64str = b64str.slice(0, canBeDecoded);
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res += this.iconv.decode(Buffer.from(b64str, 'base64'), "utf16-be");
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}
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this.inBase64 = inBase64;
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this.base64Accum = base64Accum;
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return res;
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}
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Utf7IMAPDecoder.prototype.end = function() {
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var res = "";
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if (this.inBase64 && this.base64Accum.length > 0)
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res = this.iconv.decode(Buffer.from(this.base64Accum, 'base64'), "utf16-be");
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this.inBase64 = false;
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this.base64Accum = '';
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return res;
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}
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