46 lines
1.5 KiB
JavaScript
46 lines
1.5 KiB
JavaScript
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'use strict';
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var $TypeError = require('es-errors/type');
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var IsDetachedBuffer = require('./IsDetachedBuffer');
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var isDataViewWithBufferWitnessRecord = require('../helpers/records/data-view-with-buffer-witness-record');
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var dataViewBuffer = require('data-view-buffer');
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var dataViewByteLength = require('data-view-byte-length');
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var dataViewByteOffset = require('data-view-byte-offset');
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// https://262.ecma-international.org/15.0/#sec-isviewoutofbounds
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module.exports = function IsViewOutOfBounds(viewRecord) {
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if (!isDataViewWithBufferWitnessRecord(viewRecord)) {
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throw new $TypeError('Assertion failed: `viewRecord` must be a DataView With Buffer Witness Record');
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}
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var view = viewRecord['[[Object]]']; // step 1
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var bufferByteLength = viewRecord['[[CachedBufferByteLength]]']; // step 2
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if (IsDetachedBuffer(dataViewBuffer(view)) !== (bufferByteLength === 'DETACHED')) {
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// step 3
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throw new $TypeError('Assertion failed: `IsDetachedBuffer(dataViewBuffer(view))` must be true if and only if `bufferByteLength === ~DETACHED~');
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}
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if (bufferByteLength === 'DETACHED') {
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return true; // step 4
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}
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var byteOffsetStart = dataViewByteOffset(view); // step 5
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var dvByteLength = dataViewByteLength(view);
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var byteOffsetEnd = dvByteLength === 'AUTO' ? bufferByteLength : byteOffsetStart + dvByteLength; // steps 6 - 7
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if (byteOffsetStart > bufferByteLength || byteOffsetEnd > bufferByteLength) {
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return true; // step 8
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}
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// 9. NOTE: 0-length DataViews are not considered out-of-bounds.
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return false; // step 10
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};
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