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290 lines
9.0 KiB
290 lines
9.0 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 + buf.slice(lastI, i).toString(); |
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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 + buf.slice(lastI).toString(); |
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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 + buf.slice(lastI, i).toString().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 + buf.slice(lastI).toString().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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