Messages in this thread | | | Subject | Re: [PATCH] lib: string.c: A speed optimized for strncpy | From | Joe Perches <> | Date | Sun, 05 Oct 2014 08:36:32 -0700 |
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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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