24 lines
671 B
JavaScript
24 lines
671 B
JavaScript
'use strict';
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var GetIntrinsic = require('../GetIntrinsic');
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var $TypeError = GetIntrinsic('%TypeError%');
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var $fromCharCode = GetIntrinsic('%String.fromCharCode%');
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var floor = require('./floor');
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var modulo = require('./modulo');
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// https://ecma-international.org/ecma-262/7.0/#sec-utf16encoding
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module.exports = function UTF16Encoding(cp) {
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if (typeof cp !== 'number' || cp < 0 || cp > 0x10FFFF) {
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throw new $TypeError('Assertion failed: `cp` must be >= 0 and <= 0x10FFFF');
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}
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if (cp <= 65535) {
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return cp;
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}
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var cu1 = floor((cp - 65536) / 1024) + 0xD800;
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var cu2 = modulo(cp - 65536, 1024) + 0xDC00;
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return $fromCharCode(cu1) + $fromCharCode(cu2);
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};
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