On Monday, 10 October 2016 at 03:55:17 UTC, Andrei Alexandrescu
wrote:
Oh, forgot to mention: the initial/short path should only check
for ASCII, i.e. c < 0x80. -- Andrei
void popFront1(ref char[] s) @trusted pure nothrow {
immutable c = s[0];
size_t char_length = 1;
if (!(c & 0x80)) {
goto Lend;
} else {
import core.bitop;
uint i = 7u - bsr(~c | 1u);
import std.algorithm;
if (i > 6u) goto Lend;
char_length = min(i, s.length);
}
Lend :
s = s.ptr[char_length .. s.length];
}
This one removes one unnecessary ret.
It will also probably be better for the branch-predictor.