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