ref: 776ac2e25d0dff09bc3becea409a0cdae9cde827
dir: /sys/src/libc/port/memccpy.c/
#include <u.h>
#include <libc.h>
void*
memccpy(void *a1, void *a2, int c, ulong n)
{
uchar *s1, *s2;
s1 = a1;
s2 = a2;
c &= 0xFF;
while(n > 0) {
if((*s1++ = *s2++) == c)
return s1;
n--;
}
return 0;
}