diff options
Diffstat (limited to 'middleware/node_modules/iconv-lite/encodings/utf16.js')
-rw-r--r-- | middleware/node_modules/iconv-lite/encodings/utf16.js | 177 |
1 files changed, 177 insertions, 0 deletions
diff --git a/middleware/node_modules/iconv-lite/encodings/utf16.js b/middleware/node_modules/iconv-lite/encodings/utf16.js new file mode 100644 index 0000000..54765ae --- /dev/null +++ b/middleware/node_modules/iconv-lite/encodings/utf16.js @@ -0,0 +1,177 @@ +"use strict"; +var Buffer = require("safer-buffer").Buffer; + +// Note: UTF16-LE (or UCS2) codec is Node.js native. See encodings/internal.js + +// == UTF16-BE codec. ========================================================== + +exports.utf16be = Utf16BECodec; +function Utf16BECodec() { +} + +Utf16BECodec.prototype.encoder = Utf16BEEncoder; +Utf16BECodec.prototype.decoder = Utf16BEDecoder; +Utf16BECodec.prototype.bomAware = true; + + +// -- Encoding + +function Utf16BEEncoder() { +} + +Utf16BEEncoder.prototype.write = function(str) { + var buf = Buffer.from(str, 'ucs2'); + for (var i = 0; i < buf.length; i += 2) { + var tmp = buf[i]; buf[i] = buf[i+1]; buf[i+1] = tmp; + } + return buf; +} + +Utf16BEEncoder.prototype.end = function() { +} + + +// -- Decoding + +function Utf16BEDecoder() { + this.overflowByte = -1; +} + +Utf16BEDecoder.prototype.write = function(buf) { + if (buf.length == 0) + return ''; + + var buf2 = Buffer.alloc(buf.length + 1), + i = 0, j = 0; + + if (this.overflowByte !== -1) { + buf2[0] = buf[0]; + buf2[1] = this.overflowByte; + i = 1; j = 2; + } + + for (; i < buf.length-1; i += 2, j+= 2) { + buf2[j] = buf[i+1]; + buf2[j+1] = buf[i]; + } + + this.overflowByte = (i == buf.length-1) ? buf[buf.length-1] : -1; + + return buf2.slice(0, j).toString('ucs2'); +} + +Utf16BEDecoder.prototype.end = function() { +} + + +// == UTF-16 codec ============================================================= +// Decoder chooses automatically from UTF-16LE and UTF-16BE using BOM and space-based heuristic. +// Defaults to UTF-16LE, as it's prevalent and default in Node. +// http://en.wikipedia.org/wiki/UTF-16 and http://encoding.spec.whatwg.org/#utf-16le +// Decoder default can be changed: iconv.decode(buf, 'utf16', {defaultEncoding: 'utf-16be'}); + +// Encoder uses UTF-16LE and prepends BOM (which can be overridden with addBOM: false). + +exports.utf16 = Utf16Codec; +function Utf16Codec(codecOptions, iconv) { + this.iconv = iconv; +} + +Utf16Codec.prototype.encoder = Utf16Encoder; +Utf16Codec.prototype.decoder = Utf16Decoder; + + +// -- Encoding (pass-through) + +function Utf16Encoder(options, codec) { + options = options || {}; + if (options.addBOM === undefined) + options.addBOM = true; + this.encoder = codec.iconv.getEncoder('utf-16le', options); +} + +Utf16Encoder.prototype.write = function(str) { + return this.encoder.write(str); +} + +Utf16Encoder.prototype.end = function() { + return this.encoder.end(); +} + + +// -- Decoding + +function Utf16Decoder(options, codec) { + this.decoder = null; + this.initialBytes = []; + this.initialBytesLen = 0; + + this.options = options || {}; + this.iconv = codec.iconv; +} + +Utf16Decoder.prototype.write = function(buf) { + if (!this.decoder) { + // Codec is not chosen yet. Accumulate initial bytes. + this.initialBytes.push(buf); + this.initialBytesLen += buf.length; + + if (this.initialBytesLen < 16) // We need more bytes to use space heuristic (see below) + return ''; + + // We have enough bytes -> detect endianness. + var buf = Buffer.concat(this.initialBytes), + encoding = detectEncoding(buf, this.options.defaultEncoding); + this.decoder = this.iconv.getDecoder(encoding, this.options); + this.initialBytes.length = this.initialBytesLen = 0; + } + + return this.decoder.write(buf); +} + +Utf16Decoder.prototype.end = function() { + if (!this.decoder) { + var buf = Buffer.concat(this.initialBytes), + encoding = detectEncoding(buf, this.options.defaultEncoding); + this.decoder = this.iconv.getDecoder(encoding, this.options); + + var res = this.decoder.write(buf), + trail = this.decoder.end(); + + return trail ? (res + trail) : res; + } + return this.decoder.end(); +} + +function detectEncoding(buf, defaultEncoding) { + var enc = defaultEncoding || 'utf-16le'; + + if (buf.length >= 2) { + // Check BOM. + if (buf[0] == 0xFE && buf[1] == 0xFF) // UTF-16BE BOM + enc = 'utf-16be'; + else if (buf[0] == 0xFF && buf[1] == 0xFE) // UTF-16LE BOM + enc = 'utf-16le'; + else { + // No BOM found. Try to deduce encoding from initial content. + // Most of the time, the content has ASCII chars (U+00**), but the opposite (U+**00) is uncommon. + // So, we count ASCII as if it was LE or BE, and decide from that. + var asciiCharsLE = 0, asciiCharsBE = 0, // Counts of chars in both positions + _len = Math.min(buf.length - (buf.length % 2), 64); // Len is always even. + + for (var i = 0; i < _len; i += 2) { + if (buf[i] === 0 && buf[i+1] !== 0) asciiCharsBE++; + if (buf[i] !== 0 && buf[i+1] === 0) asciiCharsLE++; + } + + if (asciiCharsBE > asciiCharsLE) + enc = 'utf-16be'; + else if (asciiCharsBE < asciiCharsLE) + enc = 'utf-16le'; + } + } + + return enc; +} + + |