/*
* UTF8.js - Implement Unicode Transformation Format 8-bit mappings
*
* Copyright © 2014-2015, 2018, JEDLSoft
*
* 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.
*/
// !data charset/UTF-8
var Charset = require("./Charset.js");
var Charmap = require("./Charmap.js");
var IString = require("./IString.js");
/**
* @class
* Create a new UTF-8 mapping instance
* @constructor
* @extends Charmap
*/
var UTF8 = function (options) {
options = options || {sync: true};
if (typeof(options.charset) === "object" && options.charset instanceof Charset) {
this.charset = options.charset;
this._init(options);
} else {
new Charset({
name: "UTF-8",
sync: options.sync,
loadParams: options.loadParams,
onLoad: ilib.bind(this, function(cs) {
this.charset = cs;
this._init(options);
})
});
}
};
UTF8.prototype = new Charmap({noinstance: true});
UTF8.prototype.parent = Charmap;
UTF8.prototype.constructor = UTF8;
/**
* Initialize the charmap instance
* @private
*/
UTF8.prototype._init = function(options) {
this._calcExpansionFactor();
if (typeof(options.onLoad) === "function") {
options.onLoad(this);
}
};
UTF8.prototype.validate = function(bytes) {
var i = 0;
while (i < bytes.length) {
if ((bytes[i] & 0x80) === 0) {
i++;
} else {
var len;
if ((bytes[i] & 0xC0) === 0xC0) {
len = 2;
} else if ((bytes[i] & 0xE0) === 0xE0) {
len = 3;
} else if ((bytes[i] & 0xF0) === 0xF0) {
len = 4;
} else {
// invalid lead byte
return false;
}
if (i + len > bytes.length) {
// not enough trailing bytes
return false;
}
for (var j = 1; j < len; j++) {
// check each trailing byte to see if it has the correct form
if ((bytes[i+j] & 0x80) !== 0x80) {
return false;
}
}
i += len;
}
}
return true;
};
UTF8.prototype.mapToUnicode = function (bytes) {
if (typeof(Buffer) !== "undefined") {
// nodejs can convert it quickly in native code
var b = Buffer.from(bytes);
return b.toString("utf8");
}
// otherwise we have to implement it in pure JS
var ret = "";
var i = 0;
while (i < bytes.length) {
if (bytes[i] === 0) {
// null-terminator
i = bytes.length;
} else if ((bytes[i] & 0x80) === 0) {
// 1 byte char
ret += String.fromCharCode(bytes[i++]);
} else if ((bytes[i] & 0xE0) === 0xC0) {
// 2 byte char
if (i + 1 >= bytes.length || (bytes[i+1] & 0x80) !== 0x80) {
throw "invalid utf-8 bytes";
}
// xxx xxyyyyyy
ret += String.fromCharCode((bytes[i] & 0x1F) << 6 | (bytes[i+1] & 0x3F));
i += 2;
} else if ((bytes[i] & 0xF0) === 0xE0) {
// 3 byte char
if (i + 2 >= bytes.length || (bytes[i+1] & 0x80) !== 0x80 || (bytes[i+2] & 0x80) !== 0x80) {
throw "invalid utf-8 bytes";
}
// xxxxyyyy yyzzzzzz
ret += String.fromCharCode((bytes[i] & 0xF) << 12 | (bytes[i+1] & 0x3F) << 6 | (bytes[i+2] & 0x3F));
i += 3;
} else if ((bytes[i] & 0xF8) === 0xF0) {
// 4 byte char
if (i + 3 >= bytes.length || (bytes[i+1] & 0x80) !== 0x80 || (bytes[i+2] & 0x80) !== 0x80 || (bytes[i+3] & 0x80) !== 0x80) {
throw "invalid utf-8 bytes";
}
// wwwxx xxxxyyyy yyzzzzzz
ret += IString.fromCodePoint((bytes[i] & 0x7) << 18 | (bytes[i+1] & 0x3F) << 12 | (bytes[i+2] & 0x3F) << 6 | (bytes[i+3] & 0x3F));
i += 4;
} else {
throw "invalid utf-8 bytes";
}
}
return ret;
};
UTF8.prototype.mapToNative = function(str) {
if (typeof(Buffer) !== "undefined") {
// nodejs can convert it quickly in native code
var b = Buffer.from(str, "utf8");
return new Uint8Array(b);
}
// otherwise we have to implement it in pure JS
var istr = (str instanceof IString) ? str : new IString(str);
// step through the surrogate pairs as single code points by using
// IString's iterator
var it = istr.iterator();
// multiply by 4 because the max size of a UTF-8 char is 4 bytes, so
// this will at least get us enough room to encode everything. Add 1
// for the null terminator
var ret = new Uint8Array(istr.length * 4 + 1);
var i = 0;
while (it.hasNext()) {
var c = it.next();
if (c > 0x7F) {
if (c > 0x7FF) {
if (c > 0xFFFF) {
// astral planes char
ret[i] = 0xF0 | ((c >> 18) & 0x3);
ret[i+1] = 0x80 | ((c >> 12) & 0x3F);
ret[i+2] = 0x80 | ((c >> 6) & 0x3F);
ret[i+3] = 0x80 | (c & 0x3F);
i += 4;
} else {
ret[i] = 0xE0 | ((c >> 12) & 0xF);
ret[i+1] = 0x80 | ((c >> 6) & 0x3F);
ret[i+2] = 0x80 | (c & 0x3F);
i += 3;
}
} else {
ret[i] = 0xC0 | ((c >> 6) & 0x1F);
ret[i+1] = 0x80 | (c & 0x3F);
i += 2;
}
} else {
ret[i++] = (c & 0x7F);
}
}
ret[i] = 0; // null-terminate it
return ret;
};
Charmap._algorithms["UTF-8"] = UTF8;
module.exports = UTF8;Source