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SubjectRe: [PATCH] memchr (trivial) optimization

On Aug 23 2007 19:13, Matt Mackall wrote:
>
>And you can do even better with this:
>
>void *memchr(const void *s, int c, size_t n)
>{
> const unsigned char *p = s, *e = s + n;
> const unsigned char *e = p + n;

Uhm, you have two "e"s in there.

> for (; p < e ; p++)
> if ((unsigned char)c == *p)
> return (void *)p;
>
> return NULL;
>}

Or do it glibc-style

void *memchr(const void *s, unsigned char c, size_t n)
{
...
for (; p + 3 < e; p += 4) {
if (c == p[0])
return (void *)&p[0];
if (c == p[1])
return (void *)&p[1];
if (c == p[2])
return (void *)&p[2];
if (c == p[3])
return (void *)&p[3];
}
... /* check the rest */
}

Jan
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