48 lines
1.8 KiB
JavaScript
48 lines
1.8 KiB
JavaScript
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'use strict';
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var $TypeError = require('es-errors/type');
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var GetPrototypeFromConstructor = require('./GetPrototypeFromConstructor');
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var IsConstructor = require('./IsConstructor');
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var IsDetachedBuffer = require('./IsDetachedBuffer');
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var OrdinarySetPrototypeOf = require('./OrdinarySetPrototypeOf');
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var isInteger = require('../helpers/isInteger');
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var isArrayBuffer = require('is-array-buffer');
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var arrayBufferSlice = require('arraybuffer.prototype.slice');
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// https://262.ecma-international.org/12.0/#sec-clonearraybuffer
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module.exports = function CloneArrayBuffer(srcBuffer, srcByteOffset, srcLength, cloneConstructor) {
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if (!isArrayBuffer(srcBuffer)) {
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throw new $TypeError('Assertion failed: `srcBuffer` must be an ArrayBuffer instance');
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}
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if (!isInteger(srcByteOffset) || srcByteOffset < 0) {
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throw new $TypeError('Assertion failed: `srcByteOffset` must be a non-negative integer');
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}
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if (!isInteger(srcLength) || srcLength < 0) {
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throw new $TypeError('Assertion failed: `srcLength` must be a non-negative integer');
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}
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if (!IsConstructor(cloneConstructor)) {
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throw new $TypeError('Assertion failed: `cloneConstructor` must be a constructor');
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}
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// 3. Let targetBuffer be ? AllocateArrayBuffer(cloneConstructor, srcLength).
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var proto = GetPrototypeFromConstructor(cloneConstructor, '%ArrayBufferPrototype%'); // step 3, kinda
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if (IsDetachedBuffer(srcBuffer)) {
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throw new $TypeError('`srcBuffer` must not be a detached ArrayBuffer'); // step 4
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}
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/*
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5. Let srcBlock be srcBuffer.[[ArrayBufferData]].
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6. Let targetBlock be targetBuffer.[[ArrayBufferData]].
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7. Perform CopyDataBlockBytes(targetBlock, 0, srcBlock, srcByteOffset, srcLength).
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*/
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var targetBuffer = arrayBufferSlice(srcBuffer, srcByteOffset, srcByteOffset + srcLength); // steps 5-7
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OrdinarySetPrototypeOf(targetBuffer, proto); // step 3
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return targetBuffer; // step 8
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};
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