1 files changed, 143 insertions, 0 deletions
diff --git a/src/libmowgli/base/random.c b/src/libmowgli/base/random.c
new file mode 100644
index 0000000..b316033
--- /dev/null
+++ b/src/libmowgli/base/random.c
@@ -0,0 +1,143 @@
+/*
+ * libmowgli: A collection of useful routines for programming.
+ * random.c: Portable mersinne-twister based psuedo-random number generator.
+ *
+ * Copyright (c) 2007 William Pitcock <nenolod -at- sacredspiral.co.uk>
+ * Algorithm copyright (c) 1999-2007 Takuji Nishimura and Makoto Matsumoto
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice is present in all copies.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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 "mowgli.h"
+
+/* period parameters */
+#define N 624
+#define M 397
+#define MATRIX_A 0x9908b0dfUL   /* constant vector a */
+#define UPPER_MASK 0x80000000UL /* most significant w-r bits */
+#define LOWER_MASK 0x7fffffffUL /* least significant r bits */
+
+/* mowgli_random_t contains state data which is private */
+struct mowgli_random_
+{
+	mowgli_object_t object;
+	unsigned int mt[N];
+	size_t mti;
+};
+
+static mowgli_object_class_t klass;
+
+/* initialization */
+void mowgli_random_bootstrap(void)
+{
+	mowgli_object_class_init(&klass, "mowgli_random_t", NULL, FALSE);
+}
+
+/* construction and destruction. */
+mowgli_random_t *mowgli_random_create(void)
+{
+	return mowgli_random_create_with_seed(time(NULL));
+}
+
+mowgli_random_t *mowgli_random_create_with_seed(unsigned int seed)
+{
+	mowgli_random_t *out = mowgli_alloc(sizeof(mowgli_random_t));
+	mowgli_object_init(mowgli_object(out), NULL, &klass, NULL);
+
+	mowgli_random_reseed(out, seed);
+
+	return out;
+}
+
+/* reset seed */
+void mowgli_random_reseed(mowgli_random_t *self, unsigned int seed)
+{
+	return_if_fail(self != NULL);
+
+	self->mt[0] = seed & 0xffffffffUL;
+	for (self->mti = 1; self->mti < N; self->mti++)
+	{
+		self->mt[self->mti] = (1812433253UL * (self->mt[self->mti - 1] ^ (self->mt[self->mti - 1] >> 30)) + self->mti);
+		self->mt[self->mti] &= 0xffffffffUL;
+	}
+}
+
+/* number retrieval */
+unsigned int mowgli_random_int(mowgli_random_t *self)
+{
+	unsigned int y;
+	static unsigned int mag01[2] = { 0x0UL, MATRIX_A };
+
+	return_val_if_fail(self != NULL, 0);
+
+	if (self->mti >= N)
+	{
+		int t;
+
+		for (t = 0; t < N - M; t++)
+		{
+			y = (self->mt[t] & UPPER_MASK) | (self->mt[t + 1] & LOWER_MASK);
+			self->mt[t] = self->mt[t + M] ^ (y >> 1) ^ mag01[y & 0x1U];
+		}
+
+		for (; t < N - 1; t++)
+		{
+			y = (self->mt[t] & UPPER_MASK) | (self->mt[t + 1] & LOWER_MASK);
+			self->mt[t] = self->mt[t + (M - N)] ^ (y >> 1) ^ mag01[y & 0x1U];			
+		}
+
+		y = (self->mt[N - 1] & UPPER_MASK) | (self->mt[0] & LOWER_MASK);
+		self->mt[N - 1] = self->mt[M - 1] ^ (y >> 1) ^ mag01[y & 0x1U];
+		self->mti = 0;
+	}
+
+	y = self->mt[self->mti++];
+
+	/* tempering */
+	y ^= (y >> 11);
+	y ^= (y << 7) & 0x9d2c5680U;
+	y ^= (y << 15) & 0xefc60000U;
+	y ^= (y >> 18);
+
+	return y;
+}
+
+int mowgli_random_int_ranged(mowgli_random_t *self, int begin, int end)
+{
+	unsigned int dist = end - begin;
+	unsigned int max, ret;
+
+	if (dist <= 0x80000000U)
+	{
+		unsigned int remain = (0x80000000U % dist) * 2;
+
+		if (remain >= dist)
+			remain -= dist;
+
+		max = 0xFFFFFFFFU - remain;
+	} else
+		max = dist - 1;
+
+	do
+	{
+		ret = mowgli_random_int(self);
+	} while (ret > max);
+
+	ret %= dist;
+
+	return begin + ret;
+}