On 04/09/2011 07:08 PM, spir wrote:
Hello,
To insert of delete an array slice, I tried to use C's memmove, thinking it
would be far faster than "manually" copying bit per bit (by any kind of magic).
But I still wrote a D versions just to check what the actual speed gain is. To
my great surprise, the C-memmove and D-manual versions perform *exactly* at the
same speed (considering measure imprecision).
Note: this remains true when elements are bigger; speed slows down slowly (eg
dchar's take only 1/3 more time).
Correction: memmove can be from 5 to 10 times faster on big arrays. For
instance, with 1_000_000 char array:
void chrono () {
char[] s;
d_time t;
enum N = 100;
// C memmove
s = ("0".mult(1_000_000)).dup;
t = getUTCtime();
foreach (_ ; 0..N) {
s.shiftEndPartC(3,5);
s[3..5] = "--";
s.shiftEndPartC(5,3);
}
t = getUTCtime() - t;
writefln("C time: %s", t);
// D manual
s = ("0".mult(1_000_000)).dup;
t = getUTCtime();
foreach (_ ; 0..N) {
s.shiftEndPartD(3,5);
s[3..5] = "--";
s.shiftEndPartD(5,3);
}
t = getUTCtime() - t;
writefln("D time: %s", t);
}
--
_________________
vita es estrany
spir.wikidot.com
