%PDF-
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Mini Shell
Mini Shell
'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 = null;
}
Utf32Decoder.prototype.write = function(src) {
if (src.length === 0)
return '';
if (this.overflow)
src = Buffer.concat([this.overflow, src]);
var goodLength = src.length - src.length % 4;
if (src.length !== goodLength) {
this.overflow = src.slice(goodLength);
src = src.slice(0, goodLength);
}
else
this.overflow = null;
var dst = Buffer.alloc(goodLength);
var offset = 0;
for (var i = 0; i < goodLength; i += 4) {
var codepoint = this.isLE ? src.readUInt32LE(i) : src.readUInt32BE(i);
if (codepoint < 0x10000) {
// Simple 16-bit character
dst.writeUInt16LE(codepoint, offset);
offset += 2;
}
else {
if (codepoint > 0x10FFFF) {
// Not a valid Unicode codepoint
dst.writeUInt16LE(this.badChar, offset);
offset += 2;
}
else {
// Create high and low surrogates.
codepoint -= 0x10000;
var high = 0xD800 | (codepoint >> 10);
var low = 0xDC00 + (codepoint & 0x3FF);
dst.writeUInt16LE(high, offset);
offset += 2;
dst.writeUInt16LE(low, offset);
offset += 2;
}
}
}
return dst.slice(0, offset).toString('ucs2');
};
Utf32Decoder.prototype.end = function() {
this.overflow = null;
};
// == 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 = Utf32AutoCodec;
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.initialBytes = [];
this.initialBytesLen = 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.initialBytes.push(buf);
this.initialBytesLen += buf.length;
if (this.initialBytesLen < 32) // We need more bytes to use space heuristic (see below)
return '';
// We have enough bytes -> detect endianness.
var buf2 = Buffer.concat(this.initialBytes),
encoding = detectEncoding(buf2, this.options.defaultEncoding);
this.decoder = this.iconv.getDecoder(encoding, this.options);
this.initialBytes.length = this.initialBytesLen = 0;
}
return this.decoder.write(buf);
};
Utf32AutoDecoder.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-32le';
if (buf.length >= 4) {
// Check BOM.
if (buf.readUInt32BE(0) === 0xFEFF) // UTF-32LE BOM
enc = 'utf-32be';
else if (buf.readUInt32LE(0) === 0xFEFF) // UTF-32LE BOM
enc = 'utf-32le';
else {
// No BOM found. Try to deduce encoding from initial content.
// Using the wrong endian-ism for UTF-32 will very often result in codepoints that are beyond
// the valid Unicode limit of 0x10FFFF. That will be used as the primary determinant.
//
// Further, we can suppose the content is mostly plain ASCII chars (U+00**).
// So, we count ASCII as if it was LE or BE, and decide from that.
var invalidLE = 0, invalidBE = 0;
var asciiCharsLE = 0, asciiCharsBE = 0, // Counts of chars in both positions
_len = Math.min(buf.length - (buf.length % 4), 128); // Len is always even.
for (var i = 0; i < _len; i += 4) {
var b0 = buf[i], b1 = buf[i + 1], b2 = buf[i + 2], b3 = buf[i + 3];
if (b0 !== 0 || b1 > 0x10) ++invalidBE;
if (b3 !== 0 || b2 > 0x10) ++invalidLE;
if (b0 === 0 && b1 === 0 && b2 === 0 && b3 !== 0) asciiCharsBE++;
if (b0 !== 0 && b1 === 0 && b2 === 0 && b3 === 0) asciiCharsLE++;
}
if (invalidBE < invalidLE)
enc = 'utf-32be';
else if (invalidLE < invalidBE)
enc = 'utf-32le';
if (asciiCharsBE > asciiCharsLE)
enc = 'utf-32be';
else if (asciiCharsBE < asciiCharsLE)
enc = 'utf-32le';
}
}
return enc;
}
Zerion Mini Shell 1.0