This patch adds a 'random' module which implements:
- random
- srandom
- initstate
- setstate
and replaces:
- rand
- srand
- RAND_MAX
It depends on the 'random_r' module.
random vs random_r
------------------
It has to be said that while it is nice to have separate 'random' and
'random_r' modules, their intimate dependence on the shared RAND_MAX
constant makes that hard to support.
For example, if a platform has RAND_MAX defined to some value which
isn't 2147483647, and the Gnulib user pulls in 'random_r' but not
'random', then they will see unexpected values returned from either
random() or random_r(). Either we override RAND_MAX with 2147483647,
or we leave RAND_MAX at the platform constant, but one way or the
other the platform random() or the Gnulib random_r() will return
values out of the expected range.
So I think long term the only supportable solution is to fold
'random_r' functionality into one big 'random' module that replaces
everything or nothing.
On Windows, RAND_MAX is defined as 0x7fff, platform rand() returns
values in this range, and they have a reputation for not being very
random. (It appears Windows offers a separate CryptoAPI if you really
wanted random numbers).
Locking
-------
As seems to be traditional with gnulib, I've removed the glibc
locking. cf. setenv and related modules. Strictly speaking this is a
violation of POSIX, since rand() is supposed to work even when called
in parallel from multiple threads. (It currently _won't_ work if you
try this - I expect you'll get strange corruption or even crashes).
I'm not sure if gnulib offers any sort of locking.
int32_t & struct random_data
----------------------------
The current implementation of the 'random_r' module doesn't actually
work for me in MinGW. It's lacking a definition of the random_data
structure.
In glibc this is defined in <stdlib.h> so I did the same thing.
However this has the side effect that we have to include <stdint.h> in
<stdlib.h> in order to get int32_t. This doesn't seem to be very
nice, but glibc does a similar thing.
Rich.
--
Richard Jones, Emerging Technologies, Red Hat http://et.redhat.com/~rjones
Read my OCaml programming blog: http://camltastic.blogspot.com/
Fedora now supports 68 OCaml packages (the OPEN alternative to F#)
http://cocan.org/getting_started_with_ocaml_on_red_hat_and_fedora
>From 92c2588b4b5a73e0bb41b27524a67241faf0b72c Mon Sep 17 00:00:00 2001
From: Richard Jones <[EMAIL PROTECTED]>
Date: Thu, 23 Oct 2008 16:53:27 +0100
Subject: [PATCH] [PATCH] Implementations of random, srandom, initstate,
setstate, rand, srand.
---
MODULES.html.sh | 1 +
doc/posix-functions/initstate.texi | 8 +-
doc/posix-functions/rand.texi | 4 +-
doc/posix-functions/random.texi | 8 +-
doc/posix-functions/setstate.texi | 8 +-
doc/posix-functions/srand.texi | 4 +-
doc/posix-functions/srandom.texi | 8 +-
lib/random.c | 208 ++++++++++++++++++++++++++++++++++++
lib/stdlib.in.h | 79 +++++++++++++-
m4/random.m4 | 21 ++++
m4/stdlib_h.m4 | 2 +
modules/random | 25 +++++
modules/stdlib | 2 +
13 files changed, 357 insertions(+), 21 deletions(-)
create mode 100644 lib/random.c
create mode 100644 m4/random.m4
create mode 100644 modules/random
diff --git a/MODULES.html.sh b/MODULES.html.sh
index cf79994..3a4fc5b 100755
--- a/MODULES.html.sh
+++ b/MODULES.html.sh
@@ -2941,6 +2941,7 @@ func_all_modules ()
func_module quotearg
func_module quote
func_module readutmp
+ func_module random
func_module random_r
func_module sysexits
func_module verror
diff --git a/doc/posix-functions/initstate.texi
b/doc/posix-functions/initstate.texi
index fc777f5..e97f631 100644
--- a/doc/posix-functions/initstate.texi
+++ b/doc/posix-functions/initstate.texi
@@ -4,15 +4,15 @@
POSIX specification: @url{http://www.opengroup.org/susv3xsh/initstate.html}
-Gnulib module: ---
+Gnulib module: random
Portability problems fixed by Gnulib:
@itemize
[EMAIL PROTECTED]
+This function is missing on some platforms:
+Solaris 2.4, mingw.
@end itemize
Portability problems not fixed by Gnulib:
@itemize
[EMAIL PROTECTED]
-This function is missing on some platforms:
-Solaris 2.4, mingw.
@end itemize
diff --git a/doc/posix-functions/rand.texi b/doc/posix-functions/rand.texi
index 8b2090f..aecfb10 100644
--- a/doc/posix-functions/rand.texi
+++ b/doc/posix-functions/rand.texi
@@ -4,10 +4,12 @@
POSIX specification: @url{http://www.opengroup.org/susv3xsh/rand.html}
-Gnulib module: ---
+Gnulib module: random
Portability problems fixed by Gnulib:
@itemize
[EMAIL PROTECTED]
+Provides a high quality PRNG on all platforms.
@end itemize
Portability problems not fixed by Gnulib:
diff --git a/doc/posix-functions/random.texi b/doc/posix-functions/random.texi
index 0111a9c..0da0ca4 100644
--- a/doc/posix-functions/random.texi
+++ b/doc/posix-functions/random.texi
@@ -4,15 +4,15 @@
POSIX specification: @url{http://www.opengroup.org/susv3xsh/random.html}
-Gnulib module: ---
+Gnulib module: random
Portability problems fixed by Gnulib:
@itemize
[EMAIL PROTECTED]
+This function is missing on some platforms:
+Solaris 2.4, mingw.
@end itemize
Portability problems not fixed by Gnulib:
@itemize
[EMAIL PROTECTED]
-This function is missing on some platforms:
-Solaris 2.4, mingw.
@end itemize
diff --git a/doc/posix-functions/setstate.texi
b/doc/posix-functions/setstate.texi
index 17b43cc..bdb1c09 100644
--- a/doc/posix-functions/setstate.texi
+++ b/doc/posix-functions/setstate.texi
@@ -4,15 +4,15 @@
POSIX specification: @url{http://www.opengroup.org/susv3xsh/setstate.html}
-Gnulib module: ---
+Gnulib module: random
Portability problems fixed by Gnulib:
@itemize
[EMAIL PROTECTED]
+This function is missing on some platforms:
+Solaris 2.4, mingw.
@end itemize
Portability problems not fixed by Gnulib:
@itemize
[EMAIL PROTECTED]
-This function is missing on some platforms:
-Solaris 2.4, mingw.
@end itemize
diff --git a/doc/posix-functions/srand.texi b/doc/posix-functions/srand.texi
index 0a93e2b..a0aab06 100644
--- a/doc/posix-functions/srand.texi
+++ b/doc/posix-functions/srand.texi
@@ -4,10 +4,12 @@
POSIX specification: @url{http://www.opengroup.org/susv3xsh/srand.html}
-Gnulib module: ---
+Gnulib module: random
Portability problems fixed by Gnulib:
@itemize
[EMAIL PROTECTED]
+Provides a high quality PRNG on all platforms.
@end itemize
Portability problems not fixed by Gnulib:
diff --git a/doc/posix-functions/srandom.texi b/doc/posix-functions/srandom.texi
index c083dcb..f4c6a47 100644
--- a/doc/posix-functions/srandom.texi
+++ b/doc/posix-functions/srandom.texi
@@ -4,15 +4,15 @@
POSIX specification: @url{http://www.opengroup.org/susv3xsh/srandom.html}
-Gnulib module: ---
+Gnulib module: random
Portability problems fixed by Gnulib:
@itemize
[EMAIL PROTECTED]
+This function is missing on some platforms:
+Solaris 2.4, mingw.
@end itemize
Portability problems not fixed by Gnulib:
@itemize
[EMAIL PROTECTED]
-This function is missing on some platforms:
-Solaris 2.4, mingw.
@end itemize
diff --git a/lib/random.c b/lib/random.c
new file mode 100644
index 0000000..6b4b8d6
--- /dev/null
+++ b/lib/random.c
@@ -0,0 +1,208 @@
+/*
+ Copyright (C) 1995, 2005, 2008 Free Software Foundation
+
+ 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, write to the Free
+ Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+ 02111-1307 USA. */
+
+/*
+ * This is derived from the Berkeley source:
+ * @(#)random.c 5.5 (Berkeley) 7/6/88
+ * It was reworked for the GNU C Library by Roland McGrath.
+ * Rewritten to use reentrant functions by Ulrich Drepper, 1995.
+ */
+
+/*
+ Copyright (C) 1983 Regents of the University of California.
+ All rights reserved.
+
+ Redistribution and use in source and binary forms, with or without
+ modification, are permitted provided that the following conditions
+ are met:
+
+ 1. Redistributions of source code must retain the above copyright
+ notice, this list of conditions and the following disclaimer.
+ 2. Redistributions in binary form must reproduce the above copyright
+ notice, this list of conditions and the following disclaimer in the
+ documentation and/or other materials provided with the distribution.
+ 4. Neither the name of the University nor the names of its contributors
+ may be used to endorse or promote products derived from this software
+ without specific prior written permission.
+
+ THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ SUCH DAMAGE.*/
+
+#include <config.h>
+
+#include <stdlib.h>
+#include <inttypes.h>
+
+/* x**31 + x**3 + 1. */
+#define TYPE_3 3
+#define BREAK_3 128
+#define DEG_3 31
+#define SEP_3 3
+
+/* Initially, everything is set up as if from:
+ initstate(1, randtbl, 128);
+ Note that this initialization takes advantage of the fact that srandom
+ advances the front and rear pointers 10*rand_deg times, and hence the
+ rear pointer which starts at 0 will also end up at zero; thus the zeroth
+ element of the state information, which contains info about the current
+ position of the rear pointer is just
+ (MAX_TYPES * (rptr - state)) + TYPE_3 == TYPE_3. */
+
+static int32_t randtbl[DEG_3 + 1] =
+ {
+ TYPE_3,
+
+ -1726662223, 379960547, 1735697613, 1040273694, 1313901226,
+ 1627687941, -179304937, -2073333483, 1780058412, -1989503057,
+ -615974602, 344556628, 939512070, -1249116260, 1507946756,
+ -812545463, 154635395, 1388815473, -1926676823, 525320961,
+ -1009028674, 968117788, -123449607, 1284210865, 435012392,
+ -2017506339, -911064859, -370259173, 1132637927, 1398500161,
+ -205601318,
+ };
+
+static struct random_data unsafe_state =
+ {
+/* FPTR and RPTR are two pointers into the state info, a front and a rear
+ pointer. These two pointers are always rand_sep places aparts, as they
+ cycle through the state information. (Yes, this does mean we could get
+ away with just one pointer, but the code for random is more efficient
+ this way). The pointers are left positioned as they would be from the call:
+ initstate(1, randtbl, 128);
+ (The position of the rear pointer, rptr, is really 0 (as explained above
+ in the initialization of randtbl) because the state table pointer is set
+ to point to randtbl[1] (as explained below).) */
+
+ .fptr = &randtbl[SEP_3 + 1],
+ .rptr = &randtbl[1],
+
+/* The following things are the pointer to the state information table,
+ the type of the current generator, the degree of the current polynomial
+ being used, and the separation between the two pointers.
+ Note that for efficiency of random, we remember the first location of
+ the state information, not the zeroth. Hence it is valid to access
+ state[-1], which is used to store the type of the R.N.G.
+ Also, we remember the last location, since this is more efficient than
+ indexing every time to find the address of the last element to see if
+ the front and rear pointers have wrapped. */
+
+ .state = &randtbl[1],
+
+ .rand_type = TYPE_3,
+ .rand_deg = DEG_3,
+ .rand_sep = SEP_3,
+
+ .end_ptr = &randtbl[sizeof (randtbl) / sizeof (randtbl[0])]
+};
+
+
+/* Initialize the random number generator based on the given seed. If the
+ type is the trivial no-state-information type, just remember the seed.
+ Otherwise, initializes state[] based on the given "seed" via a linear
+ congruential generator. Then, the pointers are set to known locations
+ that are exactly rand_sep places apart. Lastly, it cycles the state
+ information a given number of times to get rid of any initial dependencies
+ introduced by the L.C.R.N.G. Note that the initialization of randtbl[]
+ for default usage relies on values produced by this routine. */
+void
+srandom (x)
+ unsigned int x;
+{
+ (void) srandom_r (x, &unsafe_state);
+}
+
+
+/* Initialize the state information in the given array of N bytes for
+ future random number generation. Based on the number of bytes we
+ are given, and the break values for the different R.N.G.'s, we choose
+ the best (largest) one we can and set things up for it. srandom is
+ then called to initialize the state information. Note that on return
+ from srandom, we set state[-1] to be the type multiplexed with the current
+ value of the rear pointer; this is so successive calls to initstate won't
+ lose this information and will be able to restart with setstate.
+ Note: The first thing we do is save the current state, if any, just like
+ setstate so that it doesn't matter when initstate is called.
+ Returns a pointer to the old state. */
+char *
+initstate (seed, arg_state, n)
+ unsigned int seed;
+ char *arg_state;
+ size_t n;
+{
+ int32_t *ostate;
+
+ ostate = &unsafe_state.state[-1];
+
+ initstate_r (seed, arg_state, n, &unsafe_state);
+
+ return (char *) ostate;
+}
+
+
+/* Restore the state from the given state array.
+ Note: It is important that we also remember the locations of the pointers
+ in the current state information, and restore the locations of the pointers
+ from the old state information. This is done by multiplexing the pointer
+ location into the zeroth word of the state information. Note that due
+ to the order in which things are done, it is OK to call setstate with the
+ same state as the current state
+ Returns a pointer to the old state information. */
+char *
+setstate (arg_state)
+ char *arg_state;
+{
+ int32_t *ostate;
+
+ ostate = &unsafe_state.state[-1];
+
+ if (setstate_r (arg_state, &unsafe_state) < 0)
+ ostate = NULL;
+
+ return (char *) ostate;
+}
+
+
+/* If we are using the trivial TYPE_0 R.N.G., just do the old linear
+ congruential bit. Otherwise, we do our fancy trinomial stuff, which is the
+ same in all the other cases due to all the global variables that have been
+ set up. The basic operation is to add the number at the rear pointer into
+ the one at the front pointer. Then both pointers are advanced to the next
+ location cyclically in the table. The value returned is the sum generated,
+ reduced to 31 bits by throwing away the "least random" low bit.
+ Note: The code takes advantage of the fact that both the front and
+ rear pointers can't wrap on the same call by not testing the rear
+ pointer if the front one has wrapped. Returns a 31-bit random number. */
+
+long int
+random ()
+{
+ int32_t retval;
+
+ (void) random_r (&unsafe_state, &retval);
+
+ return retval;
+}
diff --git a/lib/stdlib.in.h b/lib/stdlib.in.h
index b44703b..12b834b 100644
--- a/lib/stdlib.in.h
+++ b/lib/stdlib.in.h
@@ -217,12 +217,85 @@ extern int putenv (char *string);
#endif
+#if @GNULIB_RANDOM@
+# if [EMAIL PROTECTED]@
+
+/* Remove any old definitions of RAND_MAX, since they will be
+ * incorrect for the functions we are replacing.
+ * eg. On Windows this is defined as 0x7fff.
+ */
+# undef RAND_MAX
+# define RAND_MAX 2147483647
+
+void srandom (unsigned int seed);
+char *initstate (unsigned int seed, char *buf, size_t buf_size);
+char *setstate (char *arg_state);
+long int random ();
+# undef srand
+# define srand(s) srandom(s)
+# undef rand
+# define rand() ((int)random())
+# endif
+#elif defined GNULIB_POSIXCHECK
+# undef random
+# define random() \
+ (GL_LINK_WARNING ("random is unportable - " \
+ "use gnulib module random for portability"), \
+ random ())
+# undef initstate
+# define initstate(s,b,sz) \
+ (GL_LINK_WARNING ("initstate is unportable - " \
+ "use gnulib module random for portability"), \
+ initstate (s,b,sz))
+# undef srandom
+# define srandom(s) \
+ (GL_LINK_WARNING ("srandom is unportable - " \
+ "use gnulib module random for portability"), \
+ srandom (s))
+# undef setstate
+# define setstate(a) \
+ (GL_LINK_WARNING ("setstate is unportable - " \
+ "use gnulib module random for portability"), \
+ setstate (a))
+# undef srand
+# define srand(s) \
+ (GL_LINK_WARNING ("srand is unportable and often poor quality - " \
+ "use gnulib module random for portability"), \
+ srand (a))
+# undef rand
+# define rand() \
+ (GL_LINK_WARNING ("rand is unportable and often poor quality - " \
+ "use gnulib module random for portability"), \
+ rand ())
+#endif
+
+
#if @GNULIB_RANDOM_R@
# if [EMAIL PROTECTED]@
-# ifndef RAND_MAX
-# define RAND_MAX 2147483647
-# endif
+/* Remove any old definitions of RAND_MAX, since they will be
+ * incorrect for the functions we are replacing.
+ * eg. On Windows this is defined as 0x7fff.
+ */
+#undef RAND_MAX
+#define RAND_MAX 2147483647
+
+#include <stdint.h> /* For int32_t */
+
+/* Reentrant versions of the `random' family of functions.
+ These functions all use the following data structure to contain
+ state, rather than global state variables. */
+
+struct random_data
+ {
+ int32_t *fptr; /* Front pointer. */
+ int32_t *rptr; /* Rear pointer. */
+ int32_t *state; /* Array of state values. */
+ int rand_type; /* Type of random number generator. */
+ int rand_deg; /* Degree of random number generator. */
+ int rand_sep; /* Distance between front and rear. */
+ int32_t *end_ptr; /* Pointer behind state table. */
+ };
int srandom_r (unsigned int seed, struct random_data *rand_state);
int initstate_r (unsigned int seed, char *buf, size_t buf_size,
diff --git a/m4/random.m4 b/m4/random.m4
new file mode 100644
index 0000000..d3987a8
--- /dev/null
+++ b/m4/random.m4
@@ -0,0 +1,21 @@
+# serial 1
+dnl Copyright (C) 2008 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_RANDOM],
+[
+ AC_REQUIRE([gl_STDLIB_H_DEFAULTS])
+ AC_CHECK_FUNCS([random])
+ if test $ac_cv_func_random = no; then
+ HAVE_RANDOM=0
+ AC_LIBOBJ([random])
+ gl_PREREQ_RANDOM
+ fi
+])
+
+# Prerequisites of lib/random.c.
+AC_DEFUN([gl_PREREQ_RANDOM], [
+ :
+])
diff --git a/m4/stdlib_h.m4 b/m4/stdlib_h.m4
index 3702d16..12aa558 100644
--- a/m4/stdlib_h.m4
+++ b/m4/stdlib_h.m4
@@ -28,6 +28,7 @@ AC_DEFUN([gl_STDLIB_H_DEFAULTS],
GNULIB_MKDTEMP=0; AC_SUBST([GNULIB_MKDTEMP])
GNULIB_MKSTEMP=0; AC_SUBST([GNULIB_MKSTEMP])
GNULIB_PUTENV=0; AC_SUBST([GNULIB_PUTENV])
+ GNULIB_RANDOM=0; AC_SUBST([GNULIB_RANDOM])
GNULIB_RANDOM_R=0; AC_SUBST([GNULIB_RANDOM_R])
GNULIB_RPMATCH=0; AC_SUBST([GNULIB_RPMATCH])
GNULIB_SETENV=0; AC_SUBST([GNULIB_SETENV])
@@ -42,6 +43,7 @@ AC_DEFUN([gl_STDLIB_H_DEFAULTS],
HAVE_MALLOC_POSIX=1; AC_SUBST([HAVE_MALLOC_POSIX])
HAVE_MKDTEMP=1; AC_SUBST([HAVE_MKDTEMP])
HAVE_REALLOC_POSIX=1; AC_SUBST([HAVE_REALLOC_POSIX])
+ HAVE_RANDOM=1; AC_SUBST([HAVE_RANDOM])
HAVE_RANDOM_R=1; AC_SUBST([HAVE_RANDOM_R])
HAVE_RPMATCH=1; AC_SUBST([HAVE_RPMATCH])
HAVE_SETENV=1; AC_SUBST([HAVE_SETENV])
diff --git a/modules/random b/modules/random
new file mode 100644
index 0000000..ab33752
--- /dev/null
+++ b/modules/random
@@ -0,0 +1,25 @@
+Description:
+random number generator
+
+Files:
+lib/random.c
+m4/random.m4
+
+Depends-on:
+stdlib
+random_r
+
+configure.ac:
+gl_FUNC_RANDOM
+gl_STDLIB_MODULE_INDICATOR([random])
+
+Makefile.am:
+
+Include:
+#include <stdlib.h>
+
+License:
+LGPLv2+
+
+Maintainer:
+Richard W.M. Jones
diff --git a/modules/stdlib b/modules/stdlib
index 715feea..eba20e0 100644
--- a/modules/stdlib
+++ b/modules/stdlib
@@ -33,6 +33,7 @@ stdlib.h: stdlib.in.h
-e 's|@''GNULIB_MKDTEMP''@|$(GNULIB_MKDTEMP)|g' \
-e 's|@''GNULIB_MKSTEMP''@|$(GNULIB_MKSTEMP)|g' \
-e 's|@''GNULIB_PUTENV''@|$(GNULIB_PUTENV)|g' \
+ -e 's|@''GNULIB_RANDOM''@|$(GNULIB_RANDOM)|g' \
-e 's|@''GNULIB_RANDOM_R''@|$(GNULIB_RANDOM_R)|g' \
-e 's|@''GNULIB_RPMATCH''@|$(GNULIB_RPMATCH)|g' \
-e 's|@''GNULIB_SETENV''@|$(GNULIB_SETENV)|g' \
@@ -46,6 +47,7 @@ stdlib.h: stdlib.in.h
-e 's|@''HAVE_MALLOC_POSIX''@|$(HAVE_MALLOC_POSIX)|g' \
-e 's|@''HAVE_MKDTEMP''@|$(HAVE_MKDTEMP)|g' \
-e 's|@''HAVE_REALLOC_POSIX''@|$(HAVE_REALLOC_POSIX)|g' \
+ -e 's|@''HAVE_RANDOM''@|$(HAVE_RANDOM)|g' \
-e 's|@''HAVE_RANDOM_R''@|$(HAVE_RANDOM_R)|g' \
-e 's|@''HAVE_RPMATCH''@|$(HAVE_RPMATCH)|g' \
-e 's|@''HAVE_SETENV''@|$(HAVE_SETENV)|g' \
--
1.6.0.1
