Initial commit of mtgonline project

C++/libcockatrice_rng/libcockatrice/rng/rng_sfmt.h

@@ -0,0 +1,43 @@
+#ifndef RNG_SFMT_H
+#define RNG_SFMT_H
+
+#include "rng_abstract.h"
+#include "sfmt/SFMT.h"
+
+#include <QMutex>
+#include <climits>
+
+/**
+ * This class encapsulates a state of the art PRNG and can be used
+ * to return uniformly distributed integer random numbers from a range [min, max].
+ * Though technically possible, min must be >= 0 and max should always be > 0.
+ * If max < 0 and min == 0 it is assumed that rand() % -max is wanted and the result will
+ * be -rand(0, -max).
+ * This is the only exception to the rule that !(min > max) and is actually unused in
+ * Cockatrice.
+ *
+ * Technical details:
+ * The RNG uses the SIMD-oriented Fast Mersenne Twister code v1.4.1 from
+ * http://www.math.sci.hiroshima-u.ac.jp/~%20m-mat/MT/SFMT/index.html
+ * The SFMT RNG creates unsigned int 64bit pseudo random numbers.
+ *
+ * These are mapped to values from the interval [min, max] without bias by using Knuth's
+ * "Algorithm S (Selection sampling technique)" from "The Art of Computer Programming 3rd
+ * Edition Volume 2 / Seminumerical Algorithms".
+ */
+
+class RNG_SFMT : public RNG_Abstract
+{
+    Q_OBJECT
+private:
+    QMutex mutex;
+    sfmt_t sfmt;
+    // The discrete cumulative distribution function for the RNG
+    unsigned int cdf(unsigned int min, unsigned int max);
+
+public:
+    explicit RNG_SFMT(QObject *parent = nullptr);
+    unsigned int rand(int min, int max) override;
+};
+
+#endif