50 lines
1.6 KiB
JavaScript
50 lines
1.6 KiB
JavaScript
'use strict';
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var $TypeError = require('es-errors/type');
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var floor = require('./floor');
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var IsFixedLengthArrayBuffer = require('./IsFixedLengthArrayBuffer');
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var IsTypedArrayOutOfBounds = require('./IsTypedArrayOutOfBounds');
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var TypedArrayElementSize = require('./TypedArrayElementSize');
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var isTypedArrayWithBufferWitnessRecord = require('../helpers/records/typed-array-with-buffer-witness-record');
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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 typedArrayLength = require('typed-array-length');
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// http://www.ecma-international.org/ecma-262/15.0/#sec-typedarraylength
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module.exports = function TypedArrayLength(taRecord) {
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if (!isTypedArrayWithBufferWitnessRecord(taRecord)) {
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throw new $TypeError('Assertion failed: `taRecord` must be a TypedArray With Buffer Witness Record');
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}
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if (IsTypedArrayOutOfBounds(taRecord)) {
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throw new $TypeError('Assertion failed: `taRecord` is out of bounds'); // step 1
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}
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var O = taRecord['[[Object]]']; // step 2
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var length = typedArrayLength(O);
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if (length !== 'AUTO') {
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return length; // step 3
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}
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if (IsFixedLengthArrayBuffer(typedArrayBuffer(O))) {
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throw new $TypeError('Assertion failed: array buffer is not fixed length'); // step 4
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}
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var byteOffset = typedArrayByteOffset(O); // step 5
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var elementSize = TypedArrayElementSize(O); // step 6
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var byteLength = taRecord['[[CachedBufferByteLength]]']; // step 7
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if (byteLength === 'DETACHED') {
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throw new $TypeError('Assertion failed: typed array is detached'); // step 8
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}
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return floor((byteLength - byteOffset) / elementSize); // step 9
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};
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