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-rw-r--r--stdlib/rand_r.c49
1 files changed, 49 insertions, 0 deletions
diff --git a/stdlib/rand_r.c b/stdlib/rand_r.c
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+++ b/stdlib/rand_r.c
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+/* Reentrant random function frm POSIX.1c.
+ Copyright (C) 1996 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+ Contributed by Ulrich Drepper <drepper@cygnus.com>, 1996.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Library General Public License as
+ published by the Free Software Foundation; either version 2 of the
+ License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Library General Public License for more details.
+
+ You should have received a copy of the GNU Library General Public
+ License along with the GNU C Library; see the file COPYING.LIB. If not,
+ write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ Boston, MA 02111-1307, USA. */
+
+#include <stdlib.h>
+
+
+/* This algorithm is mentioned in the ISO C standard, here extended
+ for 32 bits. */
+int
+rand_r (unsigned int *seed)
+{
+ unsigned int next = *seed;
+ int result;
+
+ next *= 1103515245;
+ next += 12345;
+ result = (unsigned int) (next / 65536) % 2048;
+
+ next *= 1103515245;
+ next += 12345;
+ result <<= 11;
+ result ^= (unsigned int) (next / 65536) % 1024;
+
+ next *= 1103515245;
+ next += 12345;
+ result <<= 10;
+ result ^= (unsigned int) (next / 65536) % 1024;
+
+ *seed = next;
+
+ return result;
+}