lib/ansi/memmove.c

   1 /*
   2  * (c) copyright 1987 by the Vrije Universiteit, Amsterdam, The Netherlands.
   3  * See the copyright notice in the ACK home directory, in the file "Copyright".
   4  */
   5 /* $Header$ */
   6
   7 #include        <string.h>
   8
   9 void *
  10 memmove(void *s1, const void *s2, register size_t n)
  11 {
  12         register char *p1 = s1;
  13         register const char *p2 = s2;
  14
  15         if (n>0) {
  16                 if (p2 <= p1 && p2 + n > p1) {
  17                         /* overlap, copy backwards */
  18                         p1 += n;
  19                         p2 += n;
  20                         n++;
  21                         while (--n > 0) {
  22                                 *--p1 = *--p2;
  23                         }
  24                 } else {
  25                         n++;
  26                         while (--n > 0) {
  27                                 *p1++ = *p2++;
  28                         }
  29                 }
  30         }
  31         return s1;
  32 }