Python/memmove.c

   1 /***********************************************************
   2 Copyright (c) 2000, BeOpen.com.
   3 Copyright (c) 1995-2000, Corporation for National Research Initiatives.
   4 Copyright (c) 1990-1995, Stichting Mathematisch Centrum.
   5 All rights reserved.
   6
   7 See the file "Misc/COPYRIGHT" for information on usage and
   8 redistribution of this file, and for a DISCLAIMER OF ALL WARRANTIES.
   9 ******************************************************************/
  10
  11 /* A perhaps slow but I hope correct implementation of memmove */
  12
  13 extern char *memcpy(char *, char *, int);
  14
  15 char *
  16 memmove(char *dst, char *src, int n)
  17 {
  18         char *realdst = dst;
  19         if (n <= 0)
  20                 return dst;
  21         if (src >= dst+n || dst >= src+n)
  22                 return memcpy(dst, src, n);
  23         if (src > dst) {
  24                 while (--n >= 0)
  25                         *dst++ = *src++;
  26         }
  27         else if (src < dst) {
  28                 src += n;
  29                 dst += n;
  30                 while (--n >= 0)
  31                         *--dst = *--src;
  32         }
  33         return realdst;
  34 }