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48 lines
1.7 KiB
48 lines
1.7 KiB
'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 IsFixedLengthArrayBuffer = require('./IsFixedLengthArrayBuffer'); |
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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 isFixed = IsFixedLengthArrayBuffer(dataViewBuffer(view)); |
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var viewByteLength = isFixed ? dataViewByteLength(view) : 'AUTO'; // view.[[ByteLength]] |
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var byteOffsetEnd = viewByteLength === 'AUTO' ? bufferByteLength : byteOffsetStart + viewByteLength; // 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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