That only applies to []byte. I have a []uint64. On Feb 23, 2017 4:13 AM, "T L" <tapir....@gmail.com> wrote:
> > > On Wednesday, February 22, 2017 at 6:53:53 AM UTC+8, Caleb Spare wrote: >> >> I have a program that uses unsafe in order to coerce some slices to >> strings for use as map keys. (Avoiding these allocations ends up being >> an important performance optimization to this program.) >> >> Here's some example code that shows what I'm doing: >> >> https://play.golang.org/p/Yye1Riv0Jj > > > Looks ok, but sliceToStringUnsafe in m[sliceToStringUnsafe(v)] = 1 is not > essential, for gc compiler has already made the same optimization for you. > Just use m[string(v)] = 1 is ok. > > >> >> >> Does this seem OK? I've tried to make sure I understand how all the >> unsafe codes fits into the blessed idioms at >> https://golang.org/pkg/unsafe/#Pointer. The part I'm most curious >> about is the indicated line: >> >> sh.Data = (*reflect.StringHeader)(unsafe.Pointer(&s)).Data // <--- >> >> This is a double-application of rule 6: it's a conversion *from* a >> reflect.StringHeader's Data field *to* a reflect.SliceHeader's Data >> field, through an unsafe.Pointer and uintptr. >> >> This code has been working for a long time and appears to continue to >> work, but I've been re-reviewing all my unsafe usage after reading the >> conversation at https://github.com/golang/go/issues/19168. >> >> Thanks for any insights. >> Caleb >> >> P.S. In this particular case, I'm planning on replacing the map with a >> custom hashtable (since it's very specialized I can do better than a >> built-in map type) and that will eliminate the unsafe code. >> > -- > 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. > -- 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.
