glibc/stdlib/rand_r.c
Paul Eggert 581c785bf3 Update copyright dates with scripts/update-copyrights
I used these shell commands:

../glibc/scripts/update-copyrights $PWD/../gnulib/build-aux/update-copyright
(cd ../glibc && git commit -am"[this commit message]")

and then ignored the output, which consisted lines saying "FOO: warning:
copyright statement not found" for each of 7061 files FOO.

I then removed trailing white space from math/tgmath.h,
support/tst-support-open-dev-null-range.c, and
sysdeps/x86_64/multiarch/strlen-vec.S, to work around the following
obscure pre-commit check failure diagnostics from Savannah.  I don't
know why I run into these diagnostics whereas others evidently do not.

remote: *** 912-#endif
remote: *** 913:
remote: *** 914-
remote: *** error: lines with trailing whitespace found
...
remote: *** error: sysdeps/unix/sysv/linux/statx_cp.c: trailing lines
2022-01-01 11:40:24 -08:00

48 lines
1.3 KiB
C

/* Reentrant random function from POSIX.1c.
Copyright (C) 1996-2022 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
#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 <<= 10;
result ^= (unsigned int) (next / 65536) % 1024;
next *= 1103515245;
next += 12345;
result <<= 10;
result ^= (unsigned int) (next / 65536) % 1024;
*seed = next;
return result;
}