59 lines
1.8 KiB
JavaScript
59 lines
1.8 KiB
JavaScript
'use strict';
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var $SyntaxError = require('es-errors/syntax');
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var $TypeError = require('es-errors/type');
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var GetValueFromBuffer = require('./GetValueFromBuffer');
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var IsDetachedBuffer = require('./IsDetachedBuffer');
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var IsInteger = require('./IsInteger');
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var isNegativeZero = require('../helpers/isNegativeZero');
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var typedArrayLength = require('typed-array-length');
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var typedArrayBuffer = require('typed-array-buffer');
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var typedArrayByteOffset = require('typed-array-byte-offset');
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var whichTypedArray = require('which-typed-array');
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var tableTAO = require('./tables/typed-array-objects');
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// https://262.ecma-international.org/6.0/#sec-integerindexedelementget
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module.exports = function IntegerIndexedElementGet(O, index) {
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if (typeof index !== 'number') {
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throw new $TypeError('`index` must be a Number'); // step 1
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}
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var arrayTypeName = whichTypedArray(O); // step 10
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if (!arrayTypeName) {
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throw new $TypeError('`O` must be a TypedArray'); // step 2
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}
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if (arrayTypeName === 'BigInt64Array' || arrayTypeName === 'BigUint64Array') {
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throw new $SyntaxError('BigInt64Array and BigUint64Array do not exist until ES2020');
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}
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var buffer = typedArrayBuffer(O); // step 3
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if (IsDetachedBuffer(buffer)) {
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throw new $TypeError('`O` has a detached buffer'); // step 4
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}
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if (!IsInteger(index) || isNegativeZero(index)) {
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return void undefined; // steps 5 - 6
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}
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var length = typedArrayLength(O); // step 7
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if (index < 0 || index >= length) {
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return void undefined; // step 8
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}
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var offset = typedArrayByteOffset(O); // step 9
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var elementType = tableTAO.name['$' + arrayTypeName]; // step 13
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var elementSize = tableTAO.size['$' + elementType]; // step 11
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var indexedPosition = (index * elementSize) + offset; // step 12
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return GetValueFromBuffer(buffer, indexedPosition, elementType); // step 14
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};
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