imap/src/ansilib/memmove2.c

   1 /* ========================================================================
   2  * Copyright 1988-2006 University of Washington
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License");
   5  * you may not use this file except in compliance with the License.
   6  * You may obtain a copy of the License at
   7  *
   8  *     http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  *
  11  * ========================================================================
  12  */
  13
  14 /*
  15  * Program:     Memory move when no bcopy()
  16  *
  17  * Author:      Mark Crispin
  18  *              Networks and Distributed Computing
  19  *              Computing & Communications
  20  *              University of Washington
  21  *              Administration Building, AG-44
  22  *              Seattle, WA  98195
  23  *              Internet: MRC@CAC.Washington.EDU
  24  *
  25  * Date:        11 May 1989
  26  * Last Edited: 30 August 2006
  27  */
  28 \f
  29 /* Copy memory block
  30  * Accepts: destination pointer
  31  *          source pointer
  32  *          length
  33  * Returns: destination pointer
  34  */
  35
  36 void *memmove (void *s,void *ct,size_t n)
  37 {
  38   char *dp,*sp;
  39   int i;
  40   unsigned long dest = (unsigned long) s;
  41   unsigned long src = (unsigned long) ct;
  42   if (((dest < src) && ((dest + n) < src)) ||
  43       ((dest > src) && ((src + n) < dest))) return (void *) memcpy (s,ct,n);
  44   dp = (char *) s;
  45   sp = (char *) ct;
  46   if (dest < src) for (i = 0; i < n; ++i) dp[i] = sp[i];
  47   else if (dest > src) for (i = n - 1; i >= 0; --i) dp[i] = sp[i];
  48   return s;
  49 }