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Diffstat (limited to 'node_modules/iconv-lite/encodings/utf32.js')
| -rw-r--r-- | node_modules/iconv-lite/encodings/utf32.js | 319 |
1 files changed, 319 insertions, 0 deletions
diff --git a/node_modules/iconv-lite/encodings/utf32.js b/node_modules/iconv-lite/encodings/utf32.js new file mode 100644 index 000000000..2fa900a12 --- /dev/null +++ b/node_modules/iconv-lite/encodings/utf32.js @@ -0,0 +1,319 @@ +'use strict'; + +var Buffer = require('safer-buffer').Buffer; + +// == UTF32-LE/BE codec. ========================================================== + +exports._utf32 = Utf32Codec; + +function Utf32Codec(codecOptions, iconv) { + this.iconv = iconv; + this.bomAware = true; + this.isLE = codecOptions.isLE; +} + +exports.utf32le = { type: '_utf32', isLE: true }; +exports.utf32be = { type: '_utf32', isLE: false }; + +// Aliases +exports.ucs4le = 'utf32le'; +exports.ucs4be = 'utf32be'; + +Utf32Codec.prototype.encoder = Utf32Encoder; +Utf32Codec.prototype.decoder = Utf32Decoder; + +// -- Encoding + +function Utf32Encoder(options, codec) { + this.isLE = codec.isLE; + this.highSurrogate = 0; +} + +Utf32Encoder.prototype.write = function(str) { + var src = Buffer.from(str, 'ucs2'); + var dst = Buffer.alloc(src.length * 2); + var write32 = this.isLE ? dst.writeUInt32LE : dst.writeUInt32BE; + var offset = 0; + + for (var i = 0; i < src.length; i += 2) { + var code = src.readUInt16LE(i); + var isHighSurrogate = (0xD800 <= code && code < 0xDC00); + var isLowSurrogate = (0xDC00 <= code && code < 0xE000); + + if (this.highSurrogate) { + if (isHighSurrogate || !isLowSurrogate) { + // There shouldn't be two high surrogates in a row, nor a high surrogate which isn't followed by a low + // surrogate. If this happens, keep the pending high surrogate as a stand-alone semi-invalid character + // (technically wrong, but expected by some applications, like Windows file names). + write32.call(dst, this.highSurrogate, offset); + offset += 4; + } + else { + // Create 32-bit value from high and low surrogates; + var codepoint = (((this.highSurrogate - 0xD800) << 10) | (code - 0xDC00)) + 0x10000; + + write32.call(dst, codepoint, offset); + offset += 4; + this.highSurrogate = 0; + + continue; + } + } + + if (isHighSurrogate) + this.highSurrogate = code; + else { + // Even if the current character is a low surrogate, with no previous high surrogate, we'll + // encode it as a semi-invalid stand-alone character for the same reasons expressed above for + // unpaired high surrogates. + write32.call(dst, code, offset); + offset += 4; + this.highSurrogate = 0; + } + } + + if (offset < dst.length) + dst = dst.slice(0, offset); + + return dst; +}; + +Utf32Encoder.prototype.end = function() { + // Treat any leftover high surrogate as a semi-valid independent character. + if (!this.highSurrogate) + return; + + var buf = Buffer.alloc(4); + + if (this.isLE) + buf.writeUInt32LE(this.highSurrogate, 0); + else + buf.writeUInt32BE(this.highSurrogate, 0); + + this.highSurrogate = 0; + + return buf; +}; + +// -- Decoding + +function Utf32Decoder(options, codec) { + this.isLE = codec.isLE; + this.badChar = codec.iconv.defaultCharUnicode.charCodeAt(0); + this.overflow = []; +} + +Utf32Decoder.prototype.write = function(src) { + if (src.length === 0) + return ''; + + var i = 0; + var codepoint = 0; + var dst = Buffer.alloc(src.length + 4); + var offset = 0; + var isLE = this.isLE; + var overflow = this.overflow; + var badChar = this.badChar; + + if (overflow.length > 0) { + for (; i < src.length && overflow.length < 4; i++) + overflow.push(src[i]); + + if (overflow.length === 4) { + // NOTE: codepoint is a signed int32 and can be negative. + // NOTE: We copied this block from below to help V8 optimize it (it works with array, not buffer). + if (isLE) { + codepoint = overflow[i] | (overflow[i+1] << 8) | (overflow[i+2] << 16) | (overflow[i+3] << 24); + } else { + codepoint = overflow[i+3] | (overflow[i+2] << 8) | (overflow[i+1] << 16) | (overflow[i] << 24); + } + overflow.length = 0; + + offset = _writeCodepoint(dst, offset, codepoint, badChar); + } + } + + // Main loop. Should be as optimized as possible. + for (; i < src.length - 3; i += 4) { + // NOTE: codepoint is a signed int32 and can be negative. + if (isLE) { + codepoint = src[i] | (src[i+1] << 8) | (src[i+2] << 16) | (src[i+3] << 24); + } else { + codepoint = src[i+3] | (src[i+2] << 8) | (src[i+1] << 16) | (src[i] << 24); + } + offset = _writeCodepoint(dst, offset, codepoint, badChar); + } + + // Keep overflowing bytes. + for (; i < src.length; i++) { + overflow.push(src[i]); + } + + return dst.slice(0, offset).toString('ucs2'); +}; + +function _writeCodepoint(dst, offset, codepoint, badChar) { + // NOTE: codepoint is signed int32 and can be negative. We keep it that way to help V8 with optimizations. + if (codepoint < 0 || codepoint > 0x10FFFF) { + // Not a valid Unicode codepoint + codepoint = badChar; + } + + // Ephemeral Planes: Write high surrogate. + if (codepoint >= 0x10000) { + codepoint -= 0x10000; + + var high = 0xD800 | (codepoint >> 10); + dst[offset++] = high & 0xff; + dst[offset++] = high >> 8; + + // Low surrogate is written below. + var codepoint = 0xDC00 | (codepoint & 0x3FF); + } + + // Write BMP char or low surrogate. + dst[offset++] = codepoint & 0xff; + dst[offset++] = codepoint >> 8; + + return offset; +}; + +Utf32Decoder.prototype.end = function() { + this.overflow.length = 0; +}; + +// == UTF-32 Auto codec ============================================================= +// Decoder chooses automatically from UTF-32LE and UTF-32BE using BOM and space-based heuristic. +// Defaults to UTF-32LE. http://en.wikipedia.org/wiki/UTF-32 +// Encoder/decoder default can be changed: iconv.decode(buf, 'utf32', {defaultEncoding: 'utf-32be'}); + +// Encoder prepends BOM (which can be overridden with (addBOM: false}). + +exports.utf32 = Utf32AutoCodec; +exports.ucs4 = 'utf32'; + +function Utf32AutoCodec(options, iconv) { + this.iconv = iconv; +} + +Utf32AutoCodec.prototype.encoder = Utf32AutoEncoder; +Utf32AutoCodec.prototype.decoder = Utf32AutoDecoder; + +// -- Encoding + +function Utf32AutoEncoder(options, codec) { + options = options || {}; + + if (options.addBOM === undefined) + options.addBOM = true; + + this.encoder = codec.iconv.getEncoder(options.defaultEncoding || 'utf-32le', options); +} + +Utf32AutoEncoder.prototype.write = function(str) { + return this.encoder.write(str); +}; + +Utf32AutoEncoder.prototype.end = function() { + return this.encoder.end(); +}; + +// -- Decoding + +function Utf32AutoDecoder(options, codec) { + this.decoder = null; + this.initialBufs = []; + this.initialBufsLen = 0; + this.options = options || {}; + this.iconv = codec.iconv; +} + +Utf32AutoDecoder.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 < 32) // 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); +}; + +Utf32AutoDecoder.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 invalidLE = 0, invalidBE = 0; // Number of invalid chars when decoded as LE or BE. + var bmpCharsLE = 0, bmpCharsBE = 0; // Number of BMP 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 === 4) { + if (charsProcessed === 0) { + // Check BOM first. + if (b[0] === 0xFF && b[1] === 0xFE && b[2] === 0 && b[3] === 0) { + return 'utf-32le'; + } + if (b[0] === 0 && b[1] === 0 && b[2] === 0xFE && b[3] === 0xFF) { + return 'utf-32be'; + } + } + + if (b[0] !== 0 || b[1] > 0x10) invalidBE++; + if (b[3] !== 0 || b[2] > 0x10) invalidLE++; + + if (b[0] === 0 && b[1] === 0 && (b[2] !== 0 || b[3] !== 0)) bmpCharsBE++; + if ((b[0] !== 0 || b[1] !== 0) && b[2] === 0 && b[3] === 0) bmpCharsLE++; + + b.length = 0; + charsProcessed++; + + if (charsProcessed >= 100) { + break outer_loop; + } + } + } + } + + // Make decisions. + if (bmpCharsBE - invalidBE > bmpCharsLE - invalidLE) return 'utf-32be'; + if (bmpCharsBE - invalidBE < bmpCharsLE - invalidLE) return 'utf-32le'; + + // Couldn't decide (likely all zeros or not enough data). + return defaultEncoding || 'utf-32le'; +} |