46 lines
1.5 KiB
JavaScript
46 lines
1.5 KiB
JavaScript
'use strict';
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var $TypeError = require('es-errors/type');
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var IsFixedLengthArrayBuffer = require('./IsFixedLengthArrayBuffer');
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var IsViewOutOfBounds = require('./IsViewOutOfBounds');
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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-getviewbytelength
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module.exports = function GetViewByteLength(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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if (IsViewOutOfBounds(viewRecord)) {
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throw new $TypeError('Assertion failed: `viewRecord` is out of bounds'); // step 1
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}
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var view = viewRecord['[[Object]]']; // step 2
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var viewByteLength = dataViewByteLength(view); // view.[[ByteLength]]
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if (viewByteLength !== 'AUTO') {
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return viewByteLength; // step 3
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}
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if (IsFixedLengthArrayBuffer(dataViewBuffer(view))) {
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throw new $TypeError('Assertion failed: DataView’s ArrayBuffer is not fixed length'); // step 4
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}
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var byteOffset = dataViewByteOffset(view); // step 5
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var byteLength = viewRecord['[[CachedBufferByteLength]]']; // step 6
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if (byteLength === 'DETACHED') {
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throw new $TypeError('Assertion failed: DataView’s ArrayBuffer is detached'); // step 7
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}
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return byteLength - byteOffset; // step 8
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};
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