Core/Utils: Moved rng functions to separate header and added utility functions to select a random element from a container where each element can have different chance of being selected

1 files changed, 72 insertions, 0 deletions

diff --git a/src/common/Utilities/Random.h b/src/common/Utilities/Random.h
new file mode 100644
index 00000000000..c919c28bcc8
--- /dev/null
+++ b/src/common/Utilities/Random.h
@@ -0,0 +1,72 @@
+/*
+ * Copyright (C) 2008-2015 TrinityCore <http://www.trinitycore.org/>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.
+ *
+ * This program 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 General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef Random_h__
+#define Random_h__
+
+#include "Define.h"
+#include <random>
+
+/* Return a random number in the range min..max. */
+int32 irand(int32 min, int32 max);
+
+/* Return a random number in the range min..max (inclusive). */
+uint32 urand(uint32 min, uint32 max);
+
+/* Return a random millisecond value between min and max seconds. Functionally equivalent to urand(min*IN_MILLISECONDS, max*IN_MILLISECONDS). */
+uint32 urandms(uint32 min, uint32 max);
+
+/* Return a random number in the range 0 .. UINT32_MAX. */
+uint32 rand32();
+
+/* Return a random number in the range min..max */
+float frand(float min, float max);
+
+/* Return a random double from 0.0 to 1.0 (exclusive). */
+double rand_norm();
+
+/* Return a random double from 0.0 to 100.0 (exclusive). */
+double rand_chance();
+
+/* Return true if a random roll fits in the specified chance (range 0-100). */
+inline bool roll_chance_f(float chance)
+{
+    return chance > rand_chance();
+}
+
+/* Return true if a random roll fits in the specified chance (range 0-100). */
+inline bool roll_chance_i(int chance)
+{
+    return chance > irand(0, 99);
+}
+
+/*
+* SFMT wrapper satisfying UniformRandomNumberGenerator concept for use in <random> algorithms
+*/
+class SFMTEngine
+{
+public:
+    typedef uint32 result_type;
+
+    result_type min() const { return std::numeric_limits<result_type>::min(); }
+    result_type max() const { return std::numeric_limits<result_type>::max(); }
+    result_type operator()() const { return rand32(); }
+
+    static SFMTEngine& Instance();
+};
+
+#endif // Random_h__