string/swab.c

   1 /* Copyright (C) 1992-2017 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, see
  16    <http://www.gnu.org/licenses/>.  */
  17
  18 #include <unistd.h>
  19
  20 void
  21 swab (const void *bfrom, void *bto, ssize_t n)
  22 {
  23   const char *from = (const char *) bfrom;
  24   char *to = (char *) bto;
  25
  26   n &= ~((ssize_t) 1);
  27   while (n > 1)
  28     {
  29       const char b0 = from[--n], b1 = from[--n];
  30       to[n] = b0;
  31       to[n + 1] = b1;
  32     }
  33 }