stdlib/jrand48_r.c

   1 /* Copyright (C) 1995, 1997 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by Ulrich Drepper <drepper@gnu.ai.mit.edu>, August 1995.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Library General Public License as
   7    published by the Free Software Foundation; either version 2 of the
   8    License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Library General Public License for more details.
  14
  15    You should have received a copy of the GNU Library General Public
  16    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  17    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  18    Boston, MA 02111-1307, USA.  */
  19
  20 #include <stdlib.h>
  21
  22 int
  23 jrand48_r (xsubi, buffer, result)
  24      unsigned short int xsubi[3];
  25      struct drand48_data *buffer;
  26      long *result;
  27 {
  28   /* Compute next state.  */
  29   if (__drand48_iterate (xsubi, buffer) < 0)
  30     return -1;
  31
  32   /* Store the result.  */
  33   if (sizeof (unsigned short int) == 2)
  34     *result = (xsubi[2] & 0x7fff) | xsubi[1];
  35   else
  36     *result = xsubi[2] & 0x7fffffffl;
  37
  38   if (xsubi[2] & (1 << (sizeof (xsubi[2]) * 8 - 1)))
  39     *result *= -1;
  40
  41   return 0;
  42 }