// $Id$
-//
+//
// A strong random number generator
//
// Copyright (C) 2006 Allen King
// 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.
+//
+// 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.
+// documentation and/or other materials provided with the distribution.
// 3. Neither the name of the project nor the names of its contributors
// may be used to endorse or promote products derived from this software
-// without specific prior written permission.
-//
+// without specific prior written permission.
+//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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
// 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
+// OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
// SUCH DAMAGE.
// Transliterated into C++ Allen King 060417, from sources on
RandomGenerator::RandomGenerator() {
assert(sizeof(int) >= 4);
initialized = 0;
+ debug = 0; // change this by hand for debug
initialize();
}
}
int RandomGenerator::srand(int x) {
- while (x == 0) // random seed of zero means
- x = (time(0) % RAND_MAX); // randomize with time
- assert(x < RAND_MAX); // only allow posative 31-bit seeds
- assert(sizeof(int) >= 4);
- srandom(x);
+ int x0 = x;
+ while (x <= 0) // random seed of zero means
+ x = time(0) % RandomGenerator::rand_max; // randomize with time
+
+ if (debug > 0)
+ printf("==== srand(%10d) (%10d) rand_max=%x =====\n",
+ x, x0, RandomGenerator::rand_max);
+
+ RandomGenerator::srandom(x);
return x; // let caller know seed used
}
-int RandomGenerator::rand() { return random(); }
+int RandomGenerator::rand() {
+ int rv; // a posative int
+ while ((rv = RandomGenerator::random()) <= 0) // neg or zero causes probs
+ ;
+ if (debug > 0)
+ printf("==== rand(): %10d =====\n", rv);
+ return rv;
+}
int RandomGenerator::rand(int v) {
- assert(v != 0 && v <= RAND_MAX); // illegal arg: 0 or too big
- return RandomGenerator::random() % v;
+ assert(v >= 0 && v <= RandomGenerator::rand_max); // illegal arg
+
+ // remove biases, esp. when v is large (e.g. v == (rand_max/4)*3;)
+ int rv, maxV =(RandomGenerator::rand_max / v) * v;
+ assert(maxV <= RandomGenerator::rand_max);
+ while ((rv = RandomGenerator::random()) >= maxV)
+ ;
+ return rv % v; // mod it down to 0..(maxV-1)
}
int RandomGenerator::rand(int u, int v) {
- assert(v > u);
+ assert(v > u);
return u + RandomGenerator::rand(v-u);
}
double RandomGenerator::randf(double v) {
float rv;
- while ((rv = (double)RandomGenerator::random() / RAND_MAX * v) >= v)
- ; // never return v!
+ do {
+ rv = ((double)RandomGenerator::random())/RandomGenerator::rand_max * v;
+ } while (rv >= v); // rounding might cause rv==v
+
+ if (debug > 0)
+ printf("==== rand(): %f =====\n", rv);
return rv;
}
}
//-----------------------------------------------------------------------
-//
+//
// Copyright (C) 2002 Michael Ringgaard. All rights reserved.
// Copyright (C) 1983, 1993 The Regents of the University of California.
//
// 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.
+//
+// 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.
+// documentation and/or other materials provided with the distribution.
// 3. Neither the name of the project nor the names of its contributors
// may be used to endorse or promote products derived from this software
-// without specific prior written permission.
-//
+// without specific prior written permission.
+//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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
// 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
+// OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
// SUCH DAMAGE.
-//
+//
//**#include <os.h>
randtbl[30] = 0x535b6b41;
randtbl[31] = 0xf3bec5da;
-// static long randtbl[DEG_3 + 1] =
+// static long randtbl[DEG_3 + 1] =
// {
// TYPE_3;
// 0x991539b1, 0x16a5bce3, 0x6774a4cd, 0x3e01511e, 0x4e508aaa, 0x61048c05,
state[0] = x;
if (rand_type == TYPE_0)
lim = NSHUFF;
- else
+ else
{
for (i = 1; i < rand_deg; i++) state[i] = good_rand(state[i - 1]);
fptr = &state[rand_sep];
done = 0;
fd = open("/dev/urandom", O_RDONLY);
- if (fd >= 0)
+ if (fd >= 0)
{
if (read(fd, state, len) == len) done = 1;
close(fd);
}
- if (!done)
+ if (!done)
{
struct timeval tv;
return;
}
- if (rand_type != TYPE_0)
+ if (rand_type != TYPE_0)
{
fptr = &state[rand_sep];
rptr = &state[0];
if (n < BREAK_0) return NULL;
- if (n < BREAK_1)
+ if (n < BREAK_1)
{
rand_type = TYPE_0;
rand_deg = DEG_0;
rand_sep = SEP_0;
- }
- else if (n < BREAK_2)
+ }
+ else if (n < BREAK_2)
{
rand_type = TYPE_1;
rand_deg = DEG_1;
rand_sep = SEP_1;
- }
- else if (n < BREAK_3)
+ }
+ else if (n < BREAK_3)
{
rand_type = TYPE_2;
rand_deg = DEG_2;
rand_sep = SEP_2;
- }
- else if (n < BREAK_4)
+ }
+ else if (n < BREAK_4)
{
rand_type = TYPE_3;
rand_deg = DEG_3;
rand_sep = SEP_3;
- }
- else
+ }
+ else
{
rand_type = TYPE_4;
rand_deg = DEG_4;
rand_sep = SEP_4;
}
-
+
state = (long *) (long_arg_state + 1); // First location
end_ptr = &state[rand_deg]; // Must set end_ptr before srandom
srandom(seed);
else
state[-1] = MAX_TYPES * (rptr - state) + rand_type;
- switch(type)
+ switch(type)
{
case TYPE_0:
case TYPE_1:
}
state = (long *) (new_state + 1);
- if (rand_type != TYPE_0)
+ if (rand_type != TYPE_0)
{
rptr = &state[rear];
fptr = &state[(rear + rand_sep) % rand_deg];
throw std::runtime_error("uninitialized RandomGenerator object");
}
- if (rand_type == TYPE_0)
+ if (rand_type == TYPE_0)
{
i = state[0];
state[0] = i = (good_rand(i)) & 0x7fffffff;
- }
- else
+ }
+ else
{
f = fptr; r = rptr;
*f += *r;
i = (*f >> 1) & 0x7fffffff; // Chucking least random bit
- if (++f >= end_ptr)
+ if (++f >= end_ptr)
{
f = state;
++r;
}
- else if (++r >= end_ptr)
+ else if (++r >= end_ptr)
r = state;
fptr = f; rptr = r;
projects / supertux.git / blobdiff