* Copyright (C) 1995-1997 Peter Mattis, Spencer Kimball and Josh MacDonald
*
* This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Library General Public
+ * modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This 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.
+ * Lesser General Public License for more details.
*
- * You should have received a copy of the GNU Library General Public
- * License along with this library; if not, write to the
- * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
- * Boston, MA 02111-1307, USA.
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, see <http://www.gnu.org/licenses/>.
*/
/* Originally developed and coded by Makoto Matsumoto and Takuji
* Nishimura. Please mail <matumoto@math.keio.ac.jp>, if you're using
* code from this file in your own programs or libraries.
* Further information on the Mersenne Twister can be found at
- * http://www.math.keio.ac.jp/~matumoto/emt.html
- * This code was adapted to glib by Sebastian Wilhelmi <wilhelmi@ira.uka.de>.
+ * http://www.math.sci.hiroshima-u.ac.jp/~m-mat/MT/emt.html
+ * This code was adapted to glib by Sebastian Wilhelmi.
*/
/*
- * Modified by the GLib Team and others 1997-1999. See the AUTHORS
+ * Modified by the GLib Team and others 1997-2000. See the AUTHORS
* file for a list of people on the GLib Team. See the ChangeLog
* files for a list of changes. These files are distributed with
- * GLib at ftp://ftp.gtk.org/pub/gtk/.
+ * GLib at ftp://ftp.gtk.org/pub/gtk/.
*/
-/*
+/*
* MT safe
*/
-#include <glib.h>
+#include "config.h"
+#define _CRT_RAND_S
+
#include <math.h>
+#include <errno.h>
#include <stdio.h>
+#include <string.h>
+#include <sys/types.h>
+#include "grand.h"
+
+#include "genviron.h"
+#include "gmain.h"
+#include "gmem.h"
+#include "gtestutils.h"
+#include "gthread.h"
+
+#ifdef G_OS_UNIX
+#include <unistd.h>
+#endif
+
+#ifdef G_OS_WIN32
+#include <stdlib.h>
+#include <process.h> /* For getpid() */
+#endif
+
+/**
+ * SECTION:random_numbers
+ * @title: Random Numbers
+ * @short_description: pseudo-random number generator
+ *
+ * The following functions allow you to use a portable, fast and good
+ * pseudo-random number generator (PRNG).
+ *
+ * Do not use this API for cryptographic purposes such as key
+ * generation, nonces, salts or one-time pads.
+ *
+ * This PRNG is suitable for non-cryptographic use such as in games
+ * (shuffling a card deck, generating levels), generating data for
+ * a test suite, etc. If you need random data for cryptographic
+ * purposes, it is recommended to use platform-specific APIs such
+ * as `/dev/random` on UNIX, or CryptGenRandom() on Windows.
+ *
+ * GRand uses the Mersenne Twister PRNG, which was originally
+ * developed by Makoto Matsumoto and Takuji Nishimura. Further
+ * information can be found at
+ * [this page](http://www.math.sci.hiroshima-u.ac.jp/~m-mat/MT/emt.html).
+ *
+ * If you just need a random number, you simply call the g_random_*
+ * functions, which will create a globally used #GRand and use the
+ * according g_rand_* functions internally. Whenever you need a
+ * stream of reproducible random numbers, you better create a
+ * #GRand yourself and use the g_rand_* functions directly, which
+ * will also be slightly faster. Initializing a #GRand with a
+ * certain seed will produce exactly the same series of random
+ * numbers on all platforms. This can thus be used as a seed for
+ * e.g. games.
+ *
+ * The g_rand*_range functions will return high quality equally
+ * distributed random numbers, whereas for example the
+ * `(g_random_int()%max)` approach often
+ * doesn't yield equally distributed numbers.
+ *
+ * GLib changed the seeding algorithm for the pseudo-random number
+ * generator Mersenne Twister, as used by #GRand. This was necessary,
+ * because some seeds would yield very bad pseudo-random streams.
+ * Also the pseudo-random integers generated by g_rand*_int_range()
+ * will have a slightly better equal distribution with the new
+ * version of GLib.
+ *
+ * The original seeding and generation algorithms, as found in
+ * GLib 2.0.x, can be used instead of the new ones by setting the
+ * environment variable `G_RANDOM_VERSION` to the value of '2.0'.
+ * Use the GLib-2.0 algorithms only if you have sequences of numbers
+ * generated with Glib-2.0 that you need to reproduce exactly.
+ */
+
+/**
+ * GRand:
+ *
+ * The GRand struct is an opaque data structure. It should only be
+ * accessed through the g_rand_* functions.
+ **/
G_LOCK_DEFINE_STATIC (global_random);
-static GRand* global_random = NULL;
/* Period parameters */
#define N 624
#define TEMPERING_SHIFT_T(y) (y << 15)
#define TEMPERING_SHIFT_L(y) (y >> 18)
+static guint
+get_random_version (void)
+{
+ static gsize initialized = FALSE;
+ static guint random_version;
+
+ if (g_once_init_enter (&initialized))
+ {
+ const gchar *version_string = g_getenv ("G_RANDOM_VERSION");
+ if (!version_string || version_string[0] == '\000' ||
+ strcmp (version_string, "2.2") == 0)
+ random_version = 22;
+ else if (strcmp (version_string, "2.0") == 0)
+ random_version = 20;
+ else
+ {
+ g_warning ("Unknown G_RANDOM_VERSION \"%s\". Using version 2.2.",
+ version_string);
+ random_version = 22;
+ }
+ g_once_init_leave (&initialized, TRUE);
+ }
+
+ return random_version;
+}
+
struct _GRand
{
guint32 mt[N]; /* the array for the state vector */
guint mti;
};
+/**
+ * g_rand_new_with_seed:
+ * @seed: a value to initialize the random number generator
+ *
+ * Creates a new random number generator initialized with @seed.
+ *
+ * Returns: the new #GRand
+ **/
GRand*
g_rand_new_with_seed (guint32 seed)
{
return rand;
}
+/**
+ * g_rand_new_with_seed_array:
+ * @seed: an array of seeds to initialize the random number generator
+ * @seed_length: an array of seeds to initialize the random number
+ * generator
+ *
+ * Creates a new random number generator initialized with @seed.
+ *
+ * Returns: the new #GRand
+ *
+ * Since: 2.4
+ */
+GRand*
+g_rand_new_with_seed_array (const guint32 *seed,
+ guint seed_length)
+{
+ GRand *rand = g_new0 (GRand, 1);
+ g_rand_set_seed_array (rand, seed, seed_length);
+ return rand;
+}
+
+/**
+ * g_rand_new:
+ *
+ * Creates a new random number generator initialized with a seed taken
+ * either from `/dev/urandom` (if existing) or from the current time
+ * (as a fallback).
+ *
+ * On Windows, the seed is taken from rand_s().
+ *
+ * Returns: the new #GRand
+ */
GRand*
g_rand_new (void)
{
- guint32 seed;
- GTimeVal now;
+ guint32 seed[4];
+#ifdef G_OS_UNIX
static gboolean dev_urandom_exists = TRUE;
-
+ GTimeVal now;
+
if (dev_urandom_exists)
{
- FILE* dev_urandom = fopen("/dev/urandom", "rb");
+ FILE* dev_urandom;
+
+ do
+ {
+ dev_urandom = fopen("/dev/urandom", "rb");
+ }
+ while G_UNLIKELY (dev_urandom == NULL && errno == EINTR);
+
if (dev_urandom)
{
- if (fread (&seed, sizeof (seed), 1, dev_urandom) != 1)
- seed = 0;
- else
+ int r;
+
+ setvbuf (dev_urandom, NULL, _IONBF, 0);
+ do
+ {
+ errno = 0;
+ r = fread (seed, sizeof (seed), 1, dev_urandom);
+ }
+ while G_UNLIKELY (errno == EINTR);
+
+ if (r != 1)
dev_urandom_exists = FALSE;
+
fclose (dev_urandom);
}
else
dev_urandom_exists = FALSE;
}
+
if (!dev_urandom_exists)
{
g_get_current_time (&now);
- seed = now.tv_sec ^ now.tv_usec;
+ seed[0] = now.tv_sec;
+ seed[1] = now.tv_usec;
+ seed[2] = getpid ();
+ seed[3] = getppid ();
}
+#else /* G_OS_WIN32 */
+ /* rand_s() is only available since Visual Studio 2005 */
+#if defined(_MSC_VER) && _MSC_VER >= 1400
+ gint i;
+
+ for (i = 0; i < G_N_ELEMENTS (seed); i++)
+ rand_s (&seed[i]);
+#else
+#warning Using insecure seed for random number generation because of missing rand_s() in Windows XP
+ GTimeVal now;
+
+ g_get_current_time (&now);
+ seed[0] = now.tv_sec;
+ seed[1] = now.tv_usec;
+ seed[2] = getpid ();
+ seed[3] = 0;
+#endif
- return g_rand_new_with_seed (seed);
+#endif
+
+ return g_rand_new_with_seed_array (seed, 4);
}
+/**
+ * g_rand_free:
+ * @rand_: a #GRand
+ *
+ * Frees the memory allocated for the #GRand.
+ */
void
-g_rand_free (GRand* rand)
+g_rand_free (GRand *rand)
{
g_return_if_fail (rand != NULL);
g_free (rand);
}
+/**
+ * g_rand_copy:
+ * @rand_: a #GRand
+ *
+ * Copies a #GRand into a new one with the same exact state as before.
+ * This way you can take a snapshot of the random number generator for
+ * replaying later.
+ *
+ * Returns: the new #GRand
+ *
+ * Since: 2.4
+ */
+GRand*
+g_rand_copy (GRand *rand)
+{
+ GRand* new_rand;
+
+ g_return_val_if_fail (rand != NULL, NULL);
+
+ new_rand = g_new0 (GRand, 1);
+ memcpy (new_rand, rand, sizeof (GRand));
+
+ return new_rand;
+}
+
+/**
+ * g_rand_set_seed:
+ * @rand_: a #GRand
+ * @seed: a value to reinitialize the random number generator
+ *
+ * Sets the seed for the random number generator #GRand to @seed.
+ */
void
-g_rand_set_seed (GRand* rand, guint32 seed)
+g_rand_set_seed (GRand *rand,
+ guint32 seed)
{
g_return_if_fail (rand != NULL);
- /* setting initial seeds to mt[N] using */
- /* the generator Line 25 of Table 1 in */
- /* [KNUTH 1981, The Art of Computer Programming */
- /* Vol. 2 (2nd Ed.), pp102] */
-
- if (seed == 0) /* This would make the PRNG procude only zeros */
- seed = 0x6b842128; /* Just set it to another number */
+ switch (get_random_version ())
+ {
+ case 20:
+ /* setting initial seeds to mt[N] using */
+ /* the generator Line 25 of Table 1 in */
+ /* [KNUTH 1981, The Art of Computer Programming */
+ /* Vol. 2 (2nd Ed.), pp102] */
+
+ if (seed == 0) /* This would make the PRNG produce only zeros */
+ seed = 0x6b842128; /* Just set it to another number */
+
+ rand->mt[0]= seed;
+ for (rand->mti=1; rand->mti<N; rand->mti++)
+ rand->mt[rand->mti] = (69069 * rand->mt[rand->mti-1]);
+
+ break;
+ case 22:
+ /* See Knuth TAOCP Vol2. 3rd Ed. P.106 for multiplier. */
+ /* In the previous version (see above), MSBs of the */
+ /* seed affect only MSBs of the array mt[]. */
+
+ rand->mt[0]= seed;
+ for (rand->mti=1; rand->mti<N; rand->mti++)
+ rand->mt[rand->mti] = 1812433253UL *
+ (rand->mt[rand->mti-1] ^ (rand->mt[rand->mti-1] >> 30)) + rand->mti;
+ break;
+ default:
+ g_assert_not_reached ();
+ }
+}
- rand->mt[0]= seed & 0xffffffff;
- for (rand->mti=1; rand->mti<N; rand->mti++)
- rand->mt[rand->mti] = (69069 * rand->mt[rand->mti-1]) & 0xffffffff;
+/**
+ * g_rand_set_seed_array:
+ * @rand_: a #GRand
+ * @seed: array to initialize with
+ * @seed_length: length of array
+ *
+ * Initializes the random number generator by an array of longs.
+ * Array can be of arbitrary size, though only the first 624 values
+ * are taken. This function is useful if you have many low entropy
+ * seeds, or if you require more then 32 bits of actual entropy for
+ * your application.
+ *
+ * Since: 2.4
+ */
+void
+g_rand_set_seed_array (GRand *rand,
+ const guint32 *seed,
+ guint seed_length)
+{
+ int i, j, k;
+
+ g_return_if_fail (rand != NULL);
+ g_return_if_fail (seed_length >= 1);
+
+ g_rand_set_seed (rand, 19650218UL);
+
+ i=1; j=0;
+ k = (N>seed_length ? N : seed_length);
+ for (; k; k--)
+ {
+ rand->mt[i] = (rand->mt[i] ^
+ ((rand->mt[i-1] ^ (rand->mt[i-1] >> 30)) * 1664525UL))
+ + seed[j] + j; /* non linear */
+ rand->mt[i] &= 0xffffffffUL; /* for WORDSIZE > 32 machines */
+ i++; j++;
+ if (i>=N)
+ {
+ rand->mt[0] = rand->mt[N-1];
+ i=1;
+ }
+ if (j>=seed_length)
+ j=0;
+ }
+ for (k=N-1; k; k--)
+ {
+ rand->mt[i] = (rand->mt[i] ^
+ ((rand->mt[i-1] ^ (rand->mt[i-1] >> 30)) * 1566083941UL))
+ - i; /* non linear */
+ rand->mt[i] &= 0xffffffffUL; /* for WORDSIZE > 32 machines */
+ i++;
+ if (i>=N)
+ {
+ rand->mt[0] = rand->mt[N-1];
+ i=1;
+ }
+ }
+
+ rand->mt[0] = 0x80000000UL; /* MSB is 1; assuring non-zero initial array */
}
+/**
+ * g_rand_boolean:
+ * @rand_: a #GRand
+ *
+ * Returns a random #gboolean from @rand_.
+ * This corresponds to a unbiased coin toss.
+ *
+ * Returns: a random #gboolean
+ */
+/**
+ * g_rand_int:
+ * @rand_: a #GRand
+ *
+ * Returns the next random #guint32 from @rand_ equally distributed over
+ * the range [0..2^32-1].
+ *
+ * Returns: a random number
+ */
guint32
-g_rand_int (GRand* rand)
+g_rand_int (GRand *rand)
{
guint32 y;
static const guint32 mag01[2]={0x0, MATRIX_A};
if (rand->mti >= N) { /* generate N words at one time */
int kk;
- for (kk=0;kk<N-M;kk++) {
+ for (kk = 0; kk < N - M; kk++) {
y = (rand->mt[kk]&UPPER_MASK)|(rand->mt[kk+1]&LOWER_MASK);
rand->mt[kk] = rand->mt[kk+M] ^ (y >> 1) ^ mag01[y & 0x1];
}
- for (;kk<N-1;kk++) {
+ for (; kk < N - 1; kk++) {
y = (rand->mt[kk]&UPPER_MASK)|(rand->mt[kk+1]&LOWER_MASK);
rand->mt[kk] = rand->mt[kk+(M-N)] ^ (y >> 1) ^ mag01[y & 0x1];
}
return y;
}
+/* transform [0..2^32] -> [0..1] */
+#define G_RAND_DOUBLE_TRANSFORM 2.3283064365386962890625e-10
+
+/**
+ * g_rand_int_range:
+ * @rand_: a #GRand
+ * @begin: lower closed bound of the interval
+ * @end: upper open bound of the interval
+ *
+ * Returns the next random #gint32 from @rand_ equally distributed over
+ * the range [@begin..@end-1].
+ *
+ * Returns: a random number
+ */
gint32
-g_rand_int_range (GRand* rand, gint32 min, gint32 max)
+g_rand_int_range (GRand *rand,
+ gint32 begin,
+ gint32 end)
{
- guint32 dist = max - min;
+ guint32 dist = end - begin;
guint32 random;
- g_return_val_if_fail (rand != NULL, min);
- g_return_val_if_fail (max > min, min);
+ g_return_val_if_fail (rand != NULL, begin);
+ g_return_val_if_fail (end > begin, begin);
- if (dist <= 0x10000L) /* 2^16 */
- {
- /* All tricks doing modulo calculations do not have a good
- distribution -> We must use this slower method for maximal
- quality, but this method is only good for (max - min) <= 2^16 */
-
- random = (gint32) g_rand_double_range (rand, 0, dist);
- /* we'd rather use the following, if -lm is allowed later on:
- random = (gint32) floor (g_rand_double_range (rand, 0, dist)); */
- }
- else
+ switch (get_random_version ())
{
- /* Now it's harder to make it right. We calculate the smallest m,
- such that dist < 2 ^ m, then we calculate a random number in
- [1..2^32-1] and rightshift it by 32 - m. Then we test, if it
- is smaller than dist and if not, get a new number and so
- forth until we get a number smaller than dist. We just return
- this. */
- guint32 border = 0x20000L; /* 2^17 */
- guint right_shift = 15; /* 32 - 17 */
-
- if (dist >= 0x80000000) /* in the case of dist > 2^31 our loop
- below will be infinite */
+ case 20:
+ if (dist <= 0x10000L) /* 2^16 */
{
- right_shift = 0;
+ /* This method, which only calls g_rand_int once is only good
+ * for (end - begin) <= 2^16, because we only have 32 bits set
+ * from the one call to g_rand_int ().
+ *
+ * We are using (trans + trans * trans), because g_rand_int only
+ * covers [0..2^32-1] and thus g_rand_int * trans only covers
+ * [0..1-2^-32], but the biggest double < 1 is 1-2^-52.
+ */
+
+ gdouble double_rand = g_rand_int (rand) *
+ (G_RAND_DOUBLE_TRANSFORM +
+ G_RAND_DOUBLE_TRANSFORM * G_RAND_DOUBLE_TRANSFORM);
+
+ random = (gint32) (double_rand * dist);
}
else
{
- while (dist >= border)
+ /* Now we use g_rand_double_range (), which will set 52 bits
+ * for us, so that it is safe to round and still get a decent
+ * distribution
+ */
+ random = (gint32) g_rand_double_range (rand, 0, dist);
+ }
+ break;
+ case 22:
+ if (dist == 0)
+ random = 0;
+ else
+ {
+ /* maxvalue is set to the predecessor of the greatest
+ * multiple of dist less or equal 2^32.
+ */
+ guint32 maxvalue;
+ if (dist <= 0x80000000u) /* 2^31 */
{
- border <<= 1;
- right_shift--;
+ /* maxvalue = 2^32 - 1 - (2^32 % dist) */
+ guint32 leftover = (0x80000000u % dist) * 2;
+ if (leftover >= dist) leftover -= dist;
+ maxvalue = 0xffffffffu - leftover;
}
+ else
+ maxvalue = dist - 1;
+
+ do
+ random = g_rand_int (rand);
+ while (random > maxvalue);
+
+ random %= dist;
}
- do
- {
- random = g_rand_int (rand) >> right_shift;
- } while (random >= dist);
- }
- return min + random;
+ break;
+ default:
+ random = 0; /* Quiet GCC */
+ g_assert_not_reached ();
+ }
+
+ return begin + random;
}
-/* transform [0..2^32-1] -> [0..1) */
-#define G_RAND_DOUBLE_TRANSFORM 2.3283064365386963e-10
-
+/**
+ * g_rand_double:
+ * @rand_: a #GRand
+ *
+ * Returns the next random #gdouble from @rand_ equally distributed over
+ * the range [0..1).
+ *
+ * Returns: a random number
+ */
gdouble
-g_rand_double (GRand* rand)
-{
- return g_rand_int (rand) * G_RAND_DOUBLE_TRANSFORM;
+g_rand_double (GRand *rand)
+{
+ /* We set all 52 bits after the point for this, not only the first
+ 32. Thats why we need two calls to g_rand_int */
+ gdouble retval = g_rand_int (rand) * G_RAND_DOUBLE_TRANSFORM;
+ retval = (retval + g_rand_int (rand)) * G_RAND_DOUBLE_TRANSFORM;
+
+ /* The following might happen due to very bad rounding luck, but
+ * actually this should be more than rare, we just try again then */
+ if (retval >= 1.0)
+ return g_rand_double (rand);
+
+ return retval;
}
+/**
+ * g_rand_double_range:
+ * @rand_: a #GRand
+ * @begin: lower closed bound of the interval
+ * @end: upper open bound of the interval
+ *
+ * Returns the next random #gdouble from @rand_ equally distributed over
+ * the range [@begin..@end).
+ *
+ * Returns: a random number
+ */
gdouble
-g_rand_double_range (GRand* rand, gdouble min, gdouble max)
+g_rand_double_range (GRand *rand,
+ gdouble begin,
+ gdouble end)
+{
+ gdouble r;
+
+ r = g_rand_double (rand);
+
+ return r * end - (r - 1) * begin;
+}
+
+static GRand *
+get_global_random (void)
{
- return g_rand_int (rand) * ((max - min) * G_RAND_DOUBLE_TRANSFORM) + min;
+ static GRand *global_random;
+
+ /* called while locked */
+ if (!global_random)
+ global_random = g_rand_new ();
+
+ return global_random;
}
+/**
+ * g_random_boolean:
+ *
+ * Returns a random #gboolean.
+ * This corresponds to a unbiased coin toss.
+ *
+ * Returns: a random #gboolean
+ */
+/**
+ * g_random_int:
+ *
+ * Return a random #guint32 equally distributed over the range
+ * [0..2^32-1].
+ *
+ * Returns: a random number
+ */
guint32
g_random_int (void)
{
guint32 result;
G_LOCK (global_random);
- if (!global_random)
- global_random = g_rand_new ();
-
- result = g_rand_int (global_random);
+ result = g_rand_int (get_global_random ());
G_UNLOCK (global_random);
return result;
}
+/**
+ * g_random_int_range:
+ * @begin: lower closed bound of the interval
+ * @end: upper open bound of the interval
+ *
+ * Returns a random #gint32 equally distributed over the range
+ * [@begin..@end-1].
+ *
+ * Returns: a random number
+ */
gint32
-g_random_int_range (gint32 min, gint32 max)
+g_random_int_range (gint32 begin,
+ gint32 end)
{
gint32 result;
G_LOCK (global_random);
- if (!global_random)
- global_random = g_rand_new ();
-
- result = g_rand_int_range (global_random, min, max);
+ result = g_rand_int_range (get_global_random (), begin, end);
G_UNLOCK (global_random);
return result;
}
+/**
+ * g_random_double:
+ *
+ * Returns a random #gdouble equally distributed over the range [0..1).
+ *
+ * Returns: a random number
+ */
gdouble
g_random_double (void)
{
double result;
G_LOCK (global_random);
- if (!global_random)
- global_random = g_rand_new ();
-
- result = g_rand_double (global_random);
+ result = g_rand_double (get_global_random ());
G_UNLOCK (global_random);
return result;
}
+/**
+ * g_random_double_range:
+ * @begin: lower closed bound of the interval
+ * @end: upper open bound of the interval
+ *
+ * Returns a random #gdouble equally distributed over the range
+ * [@begin..@end).
+ *
+ * Returns: a random number
+ */
gdouble
-g_random_double_range (gdouble min, gdouble max)
+g_random_double_range (gdouble begin,
+ gdouble end)
{
double result;
G_LOCK (global_random);
- if (!global_random)
- global_random = g_rand_new ();
-
- result = g_rand_double_range (global_random, min, max);
+ result = g_rand_double_range (get_global_random (), begin, end);
G_UNLOCK (global_random);
return result;
}
+/**
+ * g_random_set_seed:
+ * @seed: a value to reinitialize the global random number generator
+ *
+ * Sets the seed for the global random number generator, which is used
+ * by the g_random_* functions, to @seed.
+ */
void
g_random_set_seed (guint32 seed)
{
G_LOCK (global_random);
- if (!global_random)
- global_random = g_rand_new_with_seed (seed);
- else
- g_rand_set_seed (global_random, seed);
+ g_rand_set_seed (get_global_random (), seed);
G_UNLOCK (global_random);
}
-
projects / platform / upstream / glib.git / blobdiff