Added love.math.newRandomGenerator. Returns a RNG object with its own seed and random methods.

--HG--
branch : math-randobject

src/modules/math/wrap_RandomGenerator.cpp

@@ -0,0 +1,122 @@
+/**
+ * Copyright (c) 2006-2013 LOVE Development Team
+ *
+ * This software is provided 'as-is', without any express or implied
+ * warranty.  In no event will the authors be held liable for any damages
+ * arising from the use of this software.
+ *
+ * Permission is granted to anyone to use this software for any purpose,
+ * including commercial applications, and to alter it and redistribute it
+ * freely, subject to the following restrictions:
+ *
+ * 1. The origin of this software must not be misrepresented; you must not
+ *    claim that you wrote the original software. If you use this software
+ *    in a product, an acknowledgment in the product documentation would be
+ *    appreciated but is not required.
+ * 2. Altered source versions must be plainly marked as such, and must not be
+ *    misrepresented as being the original software.
+ * 3. This notice may not be removed or altered from any source distribution.
+ **/
+
+#include "wrap_RandomGenerator.h"
+
+#include <cmath>
+
+namespace love
+{
+namespace math
+{
+
+uint64 luax_checkrandomseed(lua_State *L, int idx)
+{
+	union
+	{
+		double seed_double;
+		uint64 seed_uint;
+	} s;
+
+	s.seed_double = luaL_checknumber(L, idx);
+
+	return s.seed_uint;
+}
+
+int luax_getrandom(lua_State *L, int startidx, double r)
+{
+	int l, u;
+	// from lua 5.1.4 source code: lmathlib.c:185 ff.
+	switch (lua_gettop(L) - (startidx - 1))
+	{
+	case 0:
+		lua_pushnumber(L, r);
+		break;
+	case 1:
+		u = luaL_checkint(L, startidx);
+		luaL_argcheck(L, 1 <= u, startidx, "interval is empty");
+		lua_pushnumber(L, floor(r * u) + 1);
+		break;
+	case 2:
+		l = luaL_checkint(L, startidx);
+		u = luaL_checkint(L, startidx + 1);
+		luaL_argcheck(L, l <= u, startidx + 1, "interval is empty");
+		lua_pushnumber(L, floor(r * (u - l + 1)) + l);
+		break;
+	default:
+		return luaL_error(L, "wrong number of arguments");
+	}
+	return 1;
+}
+
+RandomGenerator *luax_checkrandomgenerator(lua_State *L, int idx)
+{
+	return luax_checktype<RandomGenerator>(L, idx, "RandomGenerator", MATH_RANDOM_GENERATOR_T);
+}
+
+int w_RandomGenerator_randomseed(lua_State *L)
+{
+	RandomGenerator *rng = luax_checkrandomgenerator(L, 1);
+	uint64 seed = luax_checkrandomseed(L, 2);
+	rng->randomseed(seed);
+	return 0;
+}
+
+int w_RandomGenerator_random(lua_State *L)
+{
+	RandomGenerator *rng = luax_checkrandomgenerator(L, 1);
+	return luax_getrandom(L, 2, rng->random());
+}
+
+int w_RandomGenerator_randnormal(lua_State *L)
+{
+	RandomGenerator *rng = luax_checkrandomgenerator(L, 1);
+
+	double mean = 0.0, stddev = 1.0;
+	if (lua_gettop(L) > 2)
+	{
+		mean = luaL_checknumber(L, 2);
+		stddev = luaL_checknumber(L, 3);
+	}
+	else
+	{
+		stddev = luaL_optnumber(L, 2, 1.0);
+	}
+
+	double r = rng->randnormal(stddev);
+	lua_pushnumber(L, r + mean);
+	return 1;
+}
+
+static const luaL_Reg functions[] =
+{
+	{ "randomseed", w_RandomGenerator_randomseed },
+	{ "random", w_RandomGenerator_random },
+	{ "randnormal", w_RandomGenerator_randnormal },
+	{ 0, 0 }
+};
+
+extern "C" int luaopen_randomgenerator(lua_State *L)
+{
+	return luax_register_type(L, "RandomGenerator", functions);
+}
+
+} // math
+} // love