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Direktori : /opt/alt/alt-nodejs16/root/lib/node_modules/npm/node_modules/iconv-lite/encodings/ |
Current File : //opt/alt/alt-nodejs16/root/lib/node_modules/npm/node_modules/iconv-lite/encodings/utf16.js |
"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() { this.overflowByte = -1; } // == 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.initialBufs = []; this.initialBufsLen = 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.initialBufs.push(buf); this.initialBufsLen += buf.length; if (this.initialBufsLen < 16) // We need more bytes to use space heuristic (see below) return ''; // We have enough bytes -> detect endianness. var encoding = detectEncoding(this.initialBufs, this.options.defaultEncoding); this.decoder = this.iconv.getDecoder(encoding, this.options); var resStr = ''; for (var i = 0; i < this.initialBufs.length; i++) resStr += this.decoder.write(this.initialBufs[i]); this.initialBufs.length = this.initialBufsLen = 0; return resStr; } return this.decoder.write(buf); } Utf16Decoder.prototype.end = function() { if (!this.decoder) { var encoding = detectEncoding(this.initialBufs, this.options.defaultEncoding); this.decoder = this.iconv.getDecoder(encoding, this.options); var resStr = ''; for (var i = 0; i < this.initialBufs.length; i++) resStr += this.decoder.write(this.initialBufs[i]); var trail = this.decoder.end(); if (trail) resStr += trail; this.initialBufs.length = this.initialBufsLen = 0; return resStr; } return this.decoder.end(); } function detectEncoding(bufs, defaultEncoding) { var b = []; var charsProcessed = 0; var asciiCharsLE = 0, asciiCharsBE = 0; // Number of ASCII chars when decoded as LE or BE. outer_loop: for (var i = 0; i < bufs.length; i++) { var buf = bufs[i]; for (var j = 0; j < buf.length; j++) { b.push(buf[j]); if (b.length === 2) { if (charsProcessed === 0) { // Check BOM first. if (b[0] === 0xFF && b[1] === 0xFE) return 'utf-16le'; if (b[0] === 0xFE && b[1] === 0xFF) return 'utf-16be'; } if (b[0] === 0 && b[1] !== 0) asciiCharsBE++; if (b[0] !== 0 && b[1] === 0) asciiCharsLE++; b.length = 0; charsProcessed++; if (charsProcessed >= 100) { break outer_loop; } } } } // Make decisions. // 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. if (asciiCharsBE > asciiCharsLE) return 'utf-16be'; if (asciiCharsBE < asciiCharsLE) return 'utf-16le'; // Couldn't decide (likely all zeros or not enough data). return defaultEncoding || 'utf-16le'; }