Messages in this thread | | | From | Rickard Strandqvist <> | Date | Sun, 5 Oct 2014 18:01:43 +0200 | Subject | Re: [PATCH] lib: string.c: A speed optimized for strncpy |
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Hi
Yes, it can be faster, even if it is as you say, probably a difference depending on the size of the count. And even greater need to test this on a variety of hardware :-/
But I try to do my test with the memset variant to.
Kind regards Rickard Strandqvist
2014-10-05 17:36 GMT+02:00 Joe Perches <joe@perches.com>: > On Sun, 2014-10-05 at 15:29 +0200, Rickard Strandqvist wrote: >> This variant is in my tests about 7-10% faster, and also think >> it is perhaps even clearer code than before. > [] >> diff --git a/lib/string.c b/lib/string.c > [] >> @@ -123,12 +123,12 @@ char *strncpy(char *dest, const char *src, size_t count) >> { >> char *tmp = dest; >> >> - while (count) { >> - if ((*tmp = *src) != 0) >> - src++; >> - tmp++; >> - count--; >> - } >> + while (count && (*tmp++ = *src++)) >> + --count; >> + >> + while (count--) >> + *tmp++ = '\0'; > > Perhaps it could be faster to use memset. > It might depend on the value of count. > > { > while (count && (*tmp++ = *src++)) > count--; > > if (count > 0) > memset(tmp, 0, count); > } >
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