On Fri, Dec 7, 2018 at 10:50 AM roger peppe <rogpe...@gmail.com> wrote:
> On Fri, 7 Dec 2018, 3:26 pm 'Bryan Mills' via golang-nuts <
> golang-nuts@googlegroups.com wrote:
>
>> On Monday, December 3, 2018 at 12:02:07 AM UTC-5, Ian Lance Taylor wrote:
>>>
>>> On Sat, Dec 1, 2018 at 9:39 AM <leeo...@gmail.com> wrote:
>>> >
>>> > I am using swig wrap a c++ module , the generated go code is like
>>> this:
>>> >
>>> > type MediaFrame interface {
>>> > GetLength() uint
>>> > GetData() (*byte)
>>> > }
>>> >
>>> > I want to convert the *byte to []byte, How to do this?
>>>
>>> One approach is
>>>
>>> s :=
>>> (*[1<<30]byte)(unsafe.Pointer(mf.GetData())[:mf.GetLength():mf.GetLength()]
>>>
>>> Ian
>>>
>>
>> If you need to handle slices larger than 2³⁰ bytes, a more robust version
>> of this same approach is described in
>> https://golang.org/issue/13656#issuecomment-303216308.
>>
>>
>
> Unfortunately this approach is vulnerable to a memory leak due to
> https://golang.org/issue/28783 (and I suspect it will be quite a bit
> slower too, if performance is important). I wonder if it might be better to
> use reflect.SliceHeader guarded with some suitable regression checks.
>
Check the code at the link: it uses only one array type per element type,
so as long as the set of element types is fixed (as it usually is) it
introduces only a constant number of new types.
(It is indeed somewhat slower, but compared to the overhead of the C/Go
transition it's not terrible.)
--
You received this message because you are subscribed to the Google Groups
"golang-nuts" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to golang-nuts+unsubscr...@googlegroups.com.
For more options, visit https://groups.google.com/d/optout.
