Custom String vs D String performance

[Daniel Kozak via Digitalmars-d-learn]

Dne 5.9.2016 v 13:11 Patric via Digitalmars-d-learn napsal(a):

> I´m playing remaking D functionalities with nogc structs, and to at 
> least match D performance.
> But in this particular case i´m unable to get near D performance.  Can 
> someone point me out what i´m doing wrong, or if there is some magic 
> behind the curtains on D strings?
>
> https://dpaste.dzfl.pl/1c981fdc71ac

One of reason could be GC, because I belive in D string it reuse memory, 
but in your case you always do malloc