1  /* memmove.c -- copy memory.
       2     This file is in the public domain.  */
       3  
       4  /* Written by David MacKenzie <djm@gnu.ai.mit.edu>.  */
       5  
       6  #include <config.h>
       7  
       8  #include <stddef.h>
       9  
      10  /* Copy LENGTH bytes from SOURCE to DEST.  Does not null-terminate.  */
      11  
      12  void *
      13  memmove (void *dest0, void const *source0, size_t length)
      14  {
      15    char *dest = dest0;
      16    char const *source = source0;
      17    if (source < dest)
      18      /* Moving from low mem to hi mem; start at end.  */
      19      for (source += length, dest += length; length; --length)
      20        *--dest = *--source;
      21    else if (source != dest)
      22      {
      23        /* Moving from hi mem to low mem; start at beginning.  */
      24        for (; length; --length)
      25          *dest++ = *source++;
      26      }
      27    return dest0;
      28  }