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encoding.js
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encoding.js
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// Copyright 2014 Joshua Bell. All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// If we're in node require encoding-indexes and attach it to the global.
/**
* @fileoverview Global |this| required for resolving indexes in node.
* @suppress {globalThis}
*/
if (typeof module !== "undefined" && module.exports) {
this["encoding-indexes"] =
require("./encoding-indexes.js")["encoding-indexes"];
}
(function(global) {
'use strict';
//
// Utilities
//
/**
* @param {number} a The number to test.
* @param {number} min The minimum value in the range, inclusive.
* @param {number} max The maximum value in the range, inclusive.
* @return {boolean} True if a >= min and a <= max.
*/
function inRange(a, min, max) {
return min <= a && a <= max;
}
/**
* @param {number} n The numerator.
* @param {number} d The denominator.
* @return {number} The result of the integer division of n by d.
*/
function div(n, d) {
return Math.floor(n / d);
}
/**
* @param {*} o
* @return {Object}
*/
function ToDictionary(o) {
if (o === undefined) return {};
if (o === Object(o)) return o;
throw TypeError('Could not convert argument to dictionary');
}
/**
* @param {string} string Input string of UTF-16 code units.
* @return {!Array.<number>} Code points.
*/
function stringToCodePoints(string) {
// http://heycam.github.io/webidl/#dfn-obtain-unicode
// 1. Let S be the DOMString value.
var s = String(string);
// 2. Let n be the length of S.
var n = s.length;
// 3. Initialize i to 0.
var i = 0;
// 4. Initialize U to be an empty sequence of Unicode characters.
var u = [];
// 5. While i < n:
while (i < n) {
// 1. Let c be the code unit in S at index i.
var c = s.charCodeAt(i);
// 2. Depending on the value of c:
// c < 0xD800 or c > 0xDFFF
if (c < 0xD800 || c > 0xDFFF) {
// Append to U the Unicode character with code point c.
u.push(c);
}
// 0xDC00 ≤ c ≤ 0xDFFF
else if (0xDC00 <= c && c <= 0xDFFF) {
// Append to U a U+FFFD REPLACEMENT CHARACTER.
u.push(0xFFFD);
}
// 0xD800 ≤ c ≤ 0xDBFF
else if (0xD800 <= c && c <= 0xDBFF) {
// 1. If i = n−1, then append to U a U+FFFD REPLACEMENT
// CHARACTER.
if (i === n - 1) {
u.push(0xFFFD);
}
// 2. Otherwise, i < n−1:
else {
// 1. Let d be the code unit in S at index i+1.
var d = string.charCodeAt(i + 1);
// 2. If 0xDC00 ≤ d ≤ 0xDFFF, then:
if (0xDC00 <= d && d <= 0xDFFF) {
// 1. Let a be c & 0x3FF.
var a = c & 0x3FF;
// 2. Let b be d & 0x3FF.
var b = d & 0x3FF;
// 3. Append to U the Unicode character with code point
// 2^16+2^10*a+b.
u.push(0x10000 + (a << 10) + b);
// 4. Set i to i+1.
i += 1;
}
// 3. Otherwise, d < 0xDC00 or d > 0xDFFF. Append to U a
// U+FFFD REPLACEMENT CHARACTER.
else {
u.push(0xFFFD);
}
}
}
// 3. Set i to i+1.
i += 1;
}
// 6. Return U.
return u;
}
/**
* @param {!Array.<number>} code_points Array of code points.
* @return {string} string String of UTF-16 code units.
*/
function codePointsToString(code_points) {
var s = '';
for (var i = 0; i < code_points.length; ++i) {
var cp = code_points[i];
if (cp <= 0xFFFF) {
s += String.fromCharCode(cp);
} else {
cp -= 0x10000;
s += String.fromCharCode((cp >> 10) + 0xD800,
(cp & 0x3FF) + 0xDC00);
}
}
return s;
}
//
// Implementation of Encoding specification
// http://dvcs.w3.org/hg/encoding/raw-file/tip/Overview.html
//
//
// 3. Terminology
//
/**
* End-of-stream is a special token that signifies no more tokens
* are in the stream.
* @const
*/ var end_of_stream = -1;
/**
* A stream represents an ordered sequence of tokens.
*
* @constructor
* @param {!(Array.<number>|Uint8Array)} tokens Array of tokens that provide the
* stream.
*/
function Stream(tokens) {
/** @type {!Array.<number>} */
this.tokens = [].slice.call(tokens);
}
Stream.prototype = {
/**
* @return {boolean} True if end-of-stream has been hit.
*/
endOfStream: function() {
return !this.tokens.length;
},
/**
* When a token is read from a stream, the first token in the
* stream must be returned and subsequently removed, and
* end-of-stream must be returned otherwise.
*
* @return {number} Get the next token from the stream, or
* end_of_stream.
*/
read: function() {
if (!this.tokens.length)
return end_of_stream;
return this.tokens.shift();
},
/**
* When one or more tokens are prepended to a stream, those tokens
* must be inserted, in given order, before the first token in the
* stream.
*
* @param {(number|!Array.<number>)} token The token(s) to prepend to the stream.
*/
prepend: function(token) {
if (Array.isArray(token)) {
var tokens = /**@type {!Array.<number>}*/(token);
while (tokens.length)
this.tokens.unshift(tokens.pop());
} else {
this.tokens.unshift(token);
}
},
/**
* When one or more tokens are pushed to a stream, those tokens
* must be inserted, in given order, after the last token in the
* stream.
*
* @param {(number|!Array.<number>)} token The tokens(s) to prepend to the stream.
*/
push: function(token) {
if (Array.isArray(token)) {
var tokens = /**@type {!Array.<number>}*/(token);
while (tokens.length)
this.tokens.push(tokens.shift());
} else {
this.tokens.push(token);
}
}
};
//
// 4. Encodings
//
// 4.1 Encoders and decoders
/** @const */
var finished = -1;
/**
* @param {boolean} fatal If true, decoding errors raise an exception.
* @param {number=} opt_code_point Override the standard fallback code point.
* @return {number} The code point to insert on a decoding error.
*/
function decoderError(fatal, opt_code_point) {
if (fatal)
throw TypeError('Decoder error');
return opt_code_point || 0xFFFD;
}
/**
* @param {number} code_point The code point that could not be encoded.
* @return {number} Always throws, no value is actually returned.
*/
function encoderError(code_point) {
throw TypeError('The code point ' + code_point + ' could not be encoded.');
}
/** @interface */
function Decoder() {}
Decoder.prototype = {
/**
* @param {Stream} stream The stream of bytes being decoded.
* @param {number} bite The next byte read from the stream.
* @return {?(number|!Array.<number>)} The next code point(s)
* decoded, or null if not enough data exists in the input
* stream to decode a complete code point, or |finished|.
*/
handler: function(stream, bite) {}
};
/** @interface */
function Encoder() {}
Encoder.prototype = {
/**
* @param {Stream} stream The stream of code points being encoded.
* @param {number} code_point Next code point read from the stream.
* @return {(number|!Array.<number>)} Byte(s) to emit, or |finished|.
*/
handler: function(stream, code_point) {}
};
// 4.2 Names and labels
// TODO: Define @typedef for Encoding: {name:string,labels:Array.<string>}
// https://github.com/google/closure-compiler/issues/247
/**
* @param {string} label The encoding label.
* @return {?{name:string,labels:Array.<string>}}
*/
function getEncoding(label) {
// 1. Remove any leading and trailing ASCII whitespace from label.
label = String(label).trim().toLowerCase();
// 2. If label is an ASCII case-insensitive match for any of the
// labels listed in the table below, return the corresponding
// encoding, and failure otherwise.
if (Object.prototype.hasOwnProperty.call(label_to_encoding, label)) {
return label_to_encoding[label];
}
return null;
}
/**
* Encodings table: http://encoding.spec.whatwg.org/encodings.json
* @const
* @type {!Array.<{
* heading: string,
* encodings: Array.<{name:string,labels:Array.<string>}>
* }>}
*/
var encodings = [
{
"encodings": [
{
"labels": [
"unicode-1-1-utf-8",
"utf-8",
"utf8"
],
"name": "utf-8"
}
],
"heading": "The Encoding"
},
{
"encodings": [
{
"labels": [
"866",
"cp866",
"csibm866",
"ibm866"
],
"name": "ibm866"
},
{
"labels": [
"csisolatin2",
"iso-8859-2",
"iso-ir-101",
"iso8859-2",
"iso88592",
"iso_8859-2",
"iso_8859-2:1987",
"l2",
"latin2"
],
"name": "iso-8859-2"
},
{
"labels": [
"csisolatin3",
"iso-8859-3",
"iso-ir-109",
"iso8859-3",
"iso88593",
"iso_8859-3",
"iso_8859-3:1988",
"l3",
"latin3"
],
"name": "iso-8859-3"
},
{
"labels": [
"csisolatin4",
"iso-8859-4",
"iso-ir-110",
"iso8859-4",
"iso88594",
"iso_8859-4",
"iso_8859-4:1988",
"l4",
"latin4"
],
"name": "iso-8859-4"
},
{
"labels": [
"csisolatincyrillic",
"cyrillic",
"iso-8859-5",
"iso-ir-144",
"iso8859-5",
"iso88595",
"iso_8859-5",
"iso_8859-5:1988"
],
"name": "iso-8859-5"
},
{
"labels": [
"arabic",
"asmo-708",
"csiso88596e",
"csiso88596i",
"csisolatinarabic",
"ecma-114",
"iso-8859-6",
"iso-8859-6-e",
"iso-8859-6-i",
"iso-ir-127",
"iso8859-6",
"iso88596",
"iso_8859-6",
"iso_8859-6:1987"
],
"name": "iso-8859-6"
},
{
"labels": [
"csisolatingreek",
"ecma-118",
"elot_928",
"greek",
"greek8",
"iso-8859-7",
"iso-ir-126",
"iso8859-7",
"iso88597",
"iso_8859-7",
"iso_8859-7:1987",
"sun_eu_greek"
],
"name": "iso-8859-7"
},
{
"labels": [
"csiso88598e",
"csisolatinhebrew",
"hebrew",
"iso-8859-8",
"iso-8859-8-e",
"iso-ir-138",
"iso8859-8",
"iso88598",
"iso_8859-8",
"iso_8859-8:1988",
"visual"
],
"name": "iso-8859-8"
},
{
"labels": [
"csiso88598i",
"iso-8859-8-i",
"logical"
],
"name": "iso-8859-8-i"
},
{
"labels": [
"csisolatin6",
"iso-8859-10",
"iso-ir-157",
"iso8859-10",
"iso885910",
"l6",
"latin6"
],
"name": "iso-8859-10"
},
{
"labels": [
"iso-8859-13",
"iso8859-13",
"iso885913"
],
"name": "iso-8859-13"
},
{
"labels": [
"iso-8859-14",
"iso8859-14",
"iso885914"
],
"name": "iso-8859-14"
},
{
"labels": [
"csisolatin9",
"iso-8859-15",
"iso8859-15",
"iso885915",
"iso_8859-15",
"l9"
],
"name": "iso-8859-15"
},
{
"labels": [
"iso-8859-16"
],
"name": "iso-8859-16"
},
{
"labels": [
"cskoi8r",
"koi",
"koi8",
"koi8-r",
"koi8_r"
],
"name": "koi8-r"
},
{
"labels": [
"koi8-u"
],
"name": "koi8-u"
},
{
"labels": [
"csmacintosh",
"mac",
"macintosh",
"x-mac-roman"
],
"name": "macintosh"
},
{
"labels": [
"dos-874",
"iso-8859-11",
"iso8859-11",
"iso885911",
"tis-620",
"windows-874"
],
"name": "windows-874"
},
{
"labels": [
"cp1250",
"windows-1250",
"x-cp1250"
],
"name": "windows-1250"
},
{
"labels": [
"cp1251",
"windows-1251",
"x-cp1251"
],
"name": "windows-1251"
},
{
"labels": [
"ansi_x3.4-1968",
"ascii",
"cp1252",
"cp819",
"csisolatin1",
"ibm819",
"iso-8859-1",
"iso-ir-100",
"iso8859-1",
"iso88591",
"iso_8859-1",
"iso_8859-1:1987",
"l1",
"latin1",
"us-ascii",
"windows-1252",
"x-cp1252"
],
"name": "windows-1252"
},
{
"labels": [
"cp1253",
"windows-1253",
"x-cp1253"
],
"name": "windows-1253"
},
{
"labels": [
"cp1254",
"csisolatin5",
"iso-8859-9",
"iso-ir-148",
"iso8859-9",
"iso88599",
"iso_8859-9",
"iso_8859-9:1989",
"l5",
"latin5",
"windows-1254",
"x-cp1254"
],
"name": "windows-1254"
},
{
"labels": [
"cp1255",
"windows-1255",
"x-cp1255"
],
"name": "windows-1255"
},
{
"labels": [
"cp1256",
"windows-1256",
"x-cp1256"
],
"name": "windows-1256"
},
{
"labels": [
"cp1257",
"windows-1257",
"x-cp1257"
],
"name": "windows-1257"
},
{
"labels": [
"cp1258",
"windows-1258",
"x-cp1258"
],
"name": "windows-1258"
},
{
"labels": [
"x-mac-cyrillic",
"x-mac-ukrainian"
],
"name": "x-mac-cyrillic"
}
],
"heading": "Legacy single-byte encodings"
},
{
"encodings": [
{
"labels": [
"chinese",
"csgb2312",
"csiso58gb231280",
"gb2312",
"gb_2312",
"gb_2312-80",
"gbk",
"iso-ir-58",
"x-gbk"
],
"name": "gbk"
},
{
"labels": [
"gb18030"
],
"name": "gb18030"
}
],
"heading": "Legacy multi-byte Chinese (simplified) encodings"
},
{
"encodings": [
{
"labels": [
"big5",
"big5-hkscs",
"cn-big5",
"csbig5",
"x-x-big5"
],
"name": "big5"
}
],
"heading": "Legacy multi-byte Chinese (traditional) encodings"
},
{
"encodings": [
{
"labels": [
"cseucpkdfmtjapanese",
"euc-jp",
"x-euc-jp"
],
"name": "euc-jp"
},
{
"labels": [
"csiso2022jp",
"iso-2022-jp"
],
"name": "iso-2022-jp"
},
{
"labels": [
"csshiftjis",
"ms_kanji",
"shift-jis",
"shift_jis",
"sjis",
"windows-31j",
"x-sjis"
],
"name": "shift_jis"
}
],
"heading": "Legacy multi-byte Japanese encodings"
},
{
"encodings": [
{
"labels": [
"cseuckr",
"csksc56011987",
"euc-kr",
"iso-ir-149",
"korean",
"ks_c_5601-1987",
"ks_c_5601-1989",
"ksc5601",
"ksc_5601",
"windows-949"
],
"name": "euc-kr"
}
],
"heading": "Legacy multi-byte Korean encodings"
},
{
"encodings": [
{
"labels": [
"csiso2022kr",
"hz-gb-2312",
"iso-2022-cn",
"iso-2022-cn-ext",
"iso-2022-kr"
],
"name": "replacement"
},
{
"labels": [
"utf-16be"
],
"name": "utf-16be"
},
{
"labels": [
"utf-16",
"utf-16le"
],
"name": "utf-16le"
},
{
"labels": [
"x-user-defined"
],
"name": "x-user-defined"
}
],
"heading": "Legacy miscellaneous encodings"
}
];
// Label to encoding registry.
/** @type {Object.<string,{name:string,labels:Array.<string>}>} */
var label_to_encoding = {};
encodings.forEach(function(category) {
category.encodings.forEach(function(encoding) {
encoding.labels.forEach(function(label) {
label_to_encoding[label] = encoding;
});
});
});
// Registry of of encoder/decoder factories, by encoding name.
/** @type {Object.<string, function({fatal:boolean}): Encoder>} */
var encoders = {};
/** @type {Object.<string, function({fatal:boolean}): Decoder>} */
var decoders = {};
//
// 5. Indexes
//
/**
* @param {number} pointer The |pointer| to search for.
* @param {(!Array.<?number>|undefined)} index The |index| to search within.
* @return {?number} The code point corresponding to |pointer| in |index|,
* or null if |code point| is not in |index|.
*/
function indexCodePointFor(pointer, index) {
if (!index) return null;
return index[pointer] || null;
}
/**
* @param {number} code_point The |code point| to search for.
* @param {!Array.<?number>} index The |index| to search within.
* @return {?number} The first pointer corresponding to |code point| in
* |index|, or null if |code point| is not in |index|.
*/
function indexPointerFor(code_point, index) {
var pointer = index.indexOf(code_point);
return pointer === -1 ? null : pointer;
}
/**
* @param {string} name Name of the index.
* @return {(!Array.<number>|!Array.<Array.<number>>)}
* */
function index(name) {
if (!('encoding-indexes' in global)) {
throw Error("Indexes missing." +
" Did you forget to include encoding-indexes.js?");
}
return global['encoding-indexes'][name];
}
/**
* @param {number} pointer The |pointer| to search for in the gb18030 index.
* @return {?number} The code point corresponding to |pointer| in |index|,
* or null if |code point| is not in the gb18030 index.
*/
function indexGB18030RangesCodePointFor(pointer) {
// 1. If pointer is greater than 39419 and less than 189000, or
// pointer is greater than 1237575, return null.
if ((pointer > 39419 && pointer < 189000) || (pointer > 1237575))
return null;
// 2. Let offset be the last pointer in index gb18030 ranges that
// is equal to or less than pointer and let code point offset be
// its corresponding code point.
var offset = 0;
var code_point_offset = 0;
var idx = index('gb18030');
var i;
for (i = 0; i < idx.length; ++i) {
/** @type {!Array.<number>} */
var entry = idx[i];
if (entry[0] <= pointer) {
offset = entry[0];
code_point_offset = entry[1];
} else {
break;
}
}
// 3. Return a code point whose value is code point offset +
// pointer − offset.
return code_point_offset + pointer - offset;
}
/**
* @param {number} code_point The |code point| to locate in the gb18030 index.
* @return {number} The first pointer corresponding to |code point| in the
* gb18030 index.
*/
function indexGB18030RangesPointerFor(code_point) {
// 1. Let offset be the last code point in index gb18030 ranges
// that is equal to or less than code point and let pointer offset
// be its corresponding pointer.
var offset = 0;
var pointer_offset = 0;
var idx = index('gb18030');
var i;
for (i = 0; i < idx.length; ++i) {
/** @type {!Array.<number>} */
var entry = idx[i];
if (entry[1] <= code_point) {
offset = entry[1];
pointer_offset = entry[0];
} else {
break;
}
}
// 2. Return a pointer whose value is pointer offset + code point
// − offset.
return pointer_offset + code_point - offset;
}
/**
* @param {number} code_point The |code_point| to search for in the shift_jis index.
* @return {?number} The code point corresponding to |pointer| in |index|,
* or null if |code point| is not in the shift_jis index.
*/
function indexShiftJISPointerFor(code_point) {
// 1. Let index be index jis0208 excluding all pointers in the
// range 8272 to 8835.
var pointer = indexPointerFor(code_point, index('jis0208'));
if (pointer === null || inRange(pointer, 8272, 8835))
return null;
// 2. Return the index pointer for code point in index.
return pointer;
}
//
// 7. API
//
/** @const */ var DEFAULT_ENCODING = 'utf-8';
// 7.1 Interface TextDecoder
/**
* @constructor
* @param {string=} encoding The label of the encoding;
* defaults to 'utf-8'.
* @param {Object=} options
*/
function TextDecoder(encoding, options) {
if (!(this instanceof TextDecoder)) {
return new TextDecoder(encoding, options);
}
encoding = encoding !== undefined ? String(encoding) : DEFAULT_ENCODING;
options = ToDictionary(options);
/** @private */
this._encoding = getEncoding(encoding);
if (this._encoding === null || this._encoding.name === 'replacement')
throw RangeError('Unknown encoding: ' + encoding);
if (!decoders[this._encoding.name]) {
throw Error('Decoder not present.' +
' Did you forget to include encoding-indexes.js?');
}
/** @private @type {boolean} */
this._streaming = false;
/** @private @type {boolean} */
this._BOMseen = false;
/** @private @type {?Decoder} */
this._decoder = null;
/** @private @type {boolean} */
this._fatal = Boolean(options['fatal']);
/** @private @type {boolean} */
this._ignoreBOM = Boolean(options['ignoreBOM']);
if (Object.defineProperty) {
Object.defineProperty(this, 'encoding', {value: this._encoding.name});
Object.defineProperty(this, 'fatal', {value: this._fatal});
Object.defineProperty(this, 'ignoreBOM', {value: this._ignoreBOM});
} else {
this.encoding = this._encoding.name;
this.fatal = this._fatal;
this.ignoreBOM = this._ignoreBOM;
}
return this;
}
TextDecoder.prototype = {
/**
* @param {ArrayBufferView=} input The buffer of bytes to decode.
* @param {Object=} options
* @return {string} The decoded string.
*/
decode: function decode(input, options) {
var bytes;
if (typeof input === 'object' && input instanceof ArrayBuffer) {
bytes = new Uint8Array(input);
} else if (typeof input === 'object' && 'buffer' in input &&
input.buffer instanceof ArrayBuffer) {
bytes = new Uint8Array(input.buffer,
input.byteOffset,
input.byteLength);
} else {
bytes = new Uint8Array(0);
}
options = ToDictionary(options);
if (!this._streaming) {
this._decoder = decoders[this._encoding.name]({fatal: this._fatal});
this._BOMseen = false;
}
this._streaming = Boolean(options['stream']);
var input_stream = new Stream(bytes);