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

src/common/Utilities/Random.cpp

@@ -0,0 +1,83 @@
+/*
+ * 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/>.
+ */
+
+#include "Random.h"
+#include "Common.h"
+#include "Errors.h"
+#include "SFMT.h"
+#include <boost/thread/tss.hpp>
+
+static boost::thread_specific_ptr<SFMTRand> sfmtRand;
+
+static SFMTRand* GetRng()
+{
+    SFMTRand* rand = sfmtRand.get();
+
+    if (!rand)
+    {
+        rand = new SFMTRand();
+        sfmtRand.reset(rand);
+    }
+
+    return rand;
+}
+
+int32 irand(int32 min, int32 max)
+{
+    ASSERT(max >= min);
+    return int32(GetRng()->IRandom(min, max));
+}
+
+uint32 urand(uint32 min, uint32 max)
+{
+    ASSERT(max >= min);
+    return GetRng()->URandom(min, max);
+}
+
+uint32 urandms(uint32 min, uint32 max)
+{
+    ASSERT(max >= min);
+    ASSERT(INT_MAX / IN_MILLISECONDS >= max);
+    return GetRng()->URandom(min * IN_MILLISECONDS, max * IN_MILLISECONDS);
+}
+
+float frand(float min, float max)
+{
+    ASSERT(max >= min);
+    return float(GetRng()->Random() * (max - min) + min);
+}
+
+uint32 rand32()
+{
+    return GetRng()->BRandom();
+}
+
+double rand_norm()
+{
+    return GetRng()->Random();
+}
+
+double rand_chance()
+{
+    return GetRng()->Random() * 100.0;
+}
+
+SFMTEngine& SFMTEngine::Instance()
+{
+    static SFMTEngine engine;
+    return engine;
+}