Closed
Bug 1427812
Opened 8 years ago
Closed 7 years ago
Incorrect Polyfill function ArrayBuffer.transfer()
Categories
(Developer Documentation Graveyard :: JavaScript, enhancement, P1)
Tracking
(Not tracked)
RESOLVED
FIXED
People
(Reporter: Moritz.Hedtke, Assigned: fs)
References
()
Details
:: Developer Documentation Request
Request Type: Correction
Gecko Version: unspecified
Technical Contact:
:: Details
if (!ArrayBuffer.transfer) {
ArrayBuffer.transfer = function(source, length) {
if (!(source instanceof ArrayBuffer))
throw new TypeError('Source must be an instance of ArrayBuffer');
if (length >= source.byteLength)
return source.slice(0, length);
var sourceView = new Uint8Array(source),
destView = new Uint8Array(new ArrayBuffer(length));
destView.set(sourceView);
return dest.buffer;
};
}
has the following 2 issues:
* The if (length >= source.byteLength) check should be if (length <= source.byteLength) as source.slice(0, length) does not work if length is larger than the length of source.
* The variable dest does not exist -> should be destView
Working polyfill:
if (!ArrayBuffer.transfer) {
ArrayBuffer.transfer = function(source, length) {
if (!(source instanceof ArrayBuffer))
throw new TypeError('Source must be an instance of ArrayBuffer');
if (length <= source.byteLength)
return source.slice(0, length);
var sourceView = new Uint8Array(source),
destView = new Uint8Array(new ArrayBuffer(length));
destView.set(sourceView);
return destView.buffer;
};
}
Html for reproduction:
<!doctype html>
<html>
<head>
<title></title>
</head>
<body>
<script>
if (!ArrayBuffer.transfer) {
ArrayBuffer.transfer = function(source, length) {
if (!(source instanceof ArrayBuffer))
throw new TypeError('Source must be an instance of ArrayBuffer');
if (length <= source.byteLength)
return source.slice(0, length);
var sourceView = new Uint8Array(source),
destView = new Uint8Array(new ArrayBuffer(length));
destView.set(sourceView);
return destView.buffer;
};
}
var buf1 = new ArrayBuffer(40);
new Int32Array(buf1)[0] = 42;
var buf2 = ArrayBuffer.transfer(buf1, 80);
console.log('should be 40: ' + buf1.byteLength); // 0 but if you use the polyfill then the value is still 40
console.log('should be 80: ' + buf2.byteLength); // 80
console.log('should be 42: ' + new Int32Array(buf2)[0]); // 42
var buf3 = ArrayBuffer.transfer(buf2, 0);
console.log('should be 80: ' + buf2.byteLength); // 0 but if you use the polyfill then the value is still 80
console.log('should be 0: ' + buf3.byteLength); // 0
</script>
</body>
</html>
|
Reporter | |
Updated•8 years ago
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|
Assignee | |
Updated•8 years ago
|
Priority: P5 → P2
|
||
Updated•7 years ago
|
Assignee: nobody → fscholz
Priority: P2 → P1
|
|
Assignee | |
Comment 1•7 years ago
|
||
Thanks, this is fixed now.
Status: UNCONFIRMED → RESOLVED
Closed: 7 years ago
Resolution: --- → FIXED
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Description
•