CasperSecurity
'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';
}