I’ve got an answer on Twitter for that behavior:
https://twitter.com/phausler/status/743927492096851969
I’ve anyone like me needs Data to have a specific capacity and still be
non-optional, here is how I build a workaround (Data and Data.Deallocator
aren’t fully implemented yet, thats why I’m using a custom deallocator rather
then .free):
let capacity = 42 // or get the value somehow
let dataBufferPointer = UnsafeMutablePointer<UInt8>(allocatingCapacity:
capacity)
dataBufferPointer.initialize(with: 0, count: capacity)
// do some work and mutation to the data here
let deallocator = Data.Deallocator.custom {
(buffer, _) in
free(buffer)
}
// this initializer says you should not mutate that data after constructing it
let data = Data(bytesNoCopy: dataBufferPointer, count: capacity, deallocator:
deallocator)
--
Adrian Zubarev
Sent with Airmail
Am 19. Juni 2016 um 19:27:21, Saagar Jha (saagarjh...@gmail.com) schrieb:
Not quite:
Swift’s policy on memory allocation failure is that fixed-size object
allocation is considered to be a runtime failure if it cannot be handled. OTOH,
APIs that can take a variable and arbitrarily large amount to allocate should
be failable. NSData falls into the later category.
Source
On Sun, Jun 19, 2016 at 10:00 AM Karl <razie...@gmail.com> wrote:
As I understand it, that’s not an error in the ‘try’ sense of the word. If that
failure happens, it’s a catastrophic issue which should bring down the
application.
So the initialiser shouldn’t be failable; you’re right. File a bug at
bugs.swift.org.
Karl
On 18 Jun 2016, at 06:06, Saagar Jha via swift-users <swift-users@swift.org>
wrote:
This might be relavant. Basically, Data’s init will fail if memory can’t be
allocated for it.
On Fri, Jun 17, 2016 at 11:38 AM Adrian Zubarev via swift-users
<swift-users@swift.org> wrote:
Hello there, I’m trying to optimize my code and reduce copying from different
buffers into a new one.
I thought I just create a Data value with enough capacity and write directly
into it. My problem is that Data.init?(capacity:) can fail, but why and when?
Can someone explain this behavior to me?
I’m sending data via TCP sockets and when recn function write directly into a
Data struct.
--
Adrian Zubarev
Sent with Airmail
_______________________________________________
swift-users mailing list
swift-users@swift.org
https://lists.swift.org/mailman/listinfo/swift-users
--
-Saagar Jha
_______________________________________________
swift-users mailing list
swift-users@swift.org
https://lists.swift.org/mailman/listinfo/swift-users
--
-Saagar Jha
_______________________________________________
swift-users mailing list
swift-users@swift.org
https://lists.swift.org/mailman/listinfo/swift-users
