/*
** $Id: lmathlib.c,v 1.83.1.1 2013/04/12 18:48:47 roberto Exp $
** Standard mathematical library
** See Copyright Notice in lua.h
*/

#include <stdlib.h>
#include <math.h>

#define lmathlib_c
#define LUA_LIB

#include "lua.h"

#include "lauxlib.h"
#include "lualib.h"

#undef PI
#define PI ((lua_Number)(3.1415926535897932384626433832795))
#define RADIANS_PER_DEGREE ((lua_Number)(PI / 180.0))

static int math_abs(lua_State *L)
{
	lua_pushnumber(L, l_mathop(fabs)(luaL_checknumber(L, 1)));
	return 1;
}

static int math_sin(lua_State *L)
{
	lua_pushnumber(L, l_mathop(sin)(luaL_checknumber(L, 1)));
	return 1;
}

static int math_sinh(lua_State *L)
{
	lua_pushnumber(L, l_mathop(sinh)(luaL_checknumber(L, 1)));
	return 1;
}

static int math_cos(lua_State *L)
{
	lua_pushnumber(L, l_mathop(cos)(luaL_checknumber(L, 1)));
	return 1;
}

static int math_cosh(lua_State *L)
{
	lua_pushnumber(L, l_mathop(cosh)(luaL_checknumber(L, 1)));
	return 1;
}

static int math_tan(lua_State *L)
{
	lua_pushnumber(L, l_mathop(tan)(luaL_checknumber(L, 1)));
	return 1;
}

static int math_tanh(lua_State *L)
{
	lua_pushnumber(L, l_mathop(tanh)(luaL_checknumber(L, 1)));
	return 1;
}

static int math_asin(lua_State *L)
{
	lua_pushnumber(L, l_mathop(asin)(luaL_checknumber(L, 1)));
	return 1;
}

static int math_acos(lua_State *L)
{
	lua_pushnumber(L, l_mathop(acos)(luaL_checknumber(L, 1)));
	return 1;
}

static int math_atan(lua_State *L)
{
	lua_pushnumber(L, l_mathop(atan)(luaL_checknumber(L, 1)));
	return 1;
}

static int math_atan2(lua_State *L)
{
	lua_pushnumber(L, l_mathop(atan2)(luaL_checknumber(L, 1),
									  luaL_checknumber(L, 2)));
	return 1;
}

static int math_ceil(lua_State *L)
{
	lua_pushnumber(L, l_mathop(ceil)(luaL_checknumber(L, 1)));
	return 1;
}

static int math_floor(lua_State *L)
{
	lua_pushnumber(L, l_mathop(floor)(luaL_checknumber(L, 1)));
	return 1;
}

static int math_fmod(lua_State *L)
{
	lua_pushnumber(L, l_mathop(fmod)(luaL_checknumber(L, 1),
									 luaL_checknumber(L, 2)));
	return 1;
}

static int math_modf(lua_State *L)
{
	lua_Number ip;
	lua_Number fp = l_mathop(modf)(luaL_checknumber(L, 1), &ip);
	lua_pushnumber(L, ip);
	lua_pushnumber(L, fp);
	return 2;
}

static int math_sqrt(lua_State *L)
{
	lua_pushnumber(L, l_mathop(sqrt)(luaL_checknumber(L, 1)));
	return 1;
}

static int math_pow(lua_State *L)
{
	lua_Number x = luaL_checknumber(L, 1);
	lua_Number y = luaL_checknumber(L, 2);
	lua_pushnumber(L, l_mathop(pow)(x, y));
	return 1;
}

static int math_log(lua_State *L)
{
	lua_Number x = luaL_checknumber(L, 1);
	lua_Number res;
	if (lua_isnoneornil(L, 2))
		res = l_mathop(log)(x);
	else
	{
		lua_Number base = luaL_checknumber(L, 2);
		if (base == (lua_Number)10.0)
			res = l_mathop(log10)(x);
		else
			res = l_mathop(log)(x) / l_mathop(log)(base);
	}
	lua_pushnumber(L, res);
	return 1;
}

#if defined(LUA_COMPAT_LOG10)
static int math_log10(lua_State *L)
{
	lua_pushnumber(L, l_mathop(log10)(luaL_checknumber(L, 1)));
	return 1;
}
#endif

static int math_exp(lua_State *L)
{
	lua_pushnumber(L, l_mathop(exp)(luaL_checknumber(L, 1)));
	return 1;
}

static int math_deg(lua_State *L)
{
	lua_pushnumber(L, luaL_checknumber(L, 1) / RADIANS_PER_DEGREE);
	return 1;
}

static int math_rad(lua_State *L)
{
	lua_pushnumber(L, luaL_checknumber(L, 1) * RADIANS_PER_DEGREE);
	return 1;
}

static int math_frexp(lua_State *L)
{
	int e;
	lua_pushnumber(L, l_mathop(frexp)(luaL_checknumber(L, 1), &e));
	lua_pushinteger(L, e);
	return 2;
}

static int math_ldexp(lua_State *L)
{
	lua_Number x = luaL_checknumber(L, 1);
	int ep = luaL_checkint(L, 2);
	lua_pushnumber(L, l_mathop(ldexp)(x, ep));
	return 1;
}

static int math_min(lua_State *L)
{
	int n = lua_gettop(L); /* number of arguments */
	lua_Number dmin = luaL_checknumber(L, 1);
	int i;
	for (i = 2; i <= n; i++)
	{
		lua_Number d = luaL_checknumber(L, i);
		if (d < dmin)
			dmin = d;
	}
	lua_pushnumber(L, dmin);
	return 1;
}

static int math_max(lua_State *L)
{
	int n = lua_gettop(L); /* number of arguments */
	lua_Number dmax = luaL_checknumber(L, 1);
	int i;
	for (i = 2; i <= n; i++)
	{
		lua_Number d = luaL_checknumber(L, i);
		if (d > dmax)
			dmax = d;
	}
	lua_pushnumber(L, dmax);
	return 1;
}

static int math_random(lua_State *L)
{
	/* the `%' avoids the (rare) case of r==1, and is needed also because on
     some systems (SunOS!) `rand()' may return a value larger than RAND_MAX */
	lua_Number r = (lua_Number)(rand() % RAND_MAX) / (lua_Number)RAND_MAX;
	switch (lua_gettop(L))
	{ /* check number of arguments */
		case 0:
		{                         /* no arguments */
			lua_pushnumber(L, r); /* Number between 0 and 1 */
			break;
		}
		case 1:
		{ /* only upper limit */
			lua_Number u = luaL_checknumber(L, 1);
			luaL_argcheck(L, (lua_Number)1.0 <= u, 1, "interval is empty");
			lua_pushnumber(L, l_mathop(floor)(r * u) + (lua_Number)(1.0)); /* [1, u] */
			break;
		}
		case 2:
		{ /* lower and upper limits */
			lua_Number l = luaL_checknumber(L, 1);
			lua_Number u = luaL_checknumber(L, 2);
			luaL_argcheck(L, l <= u, 2, "interval is empty");
			lua_pushnumber(L, l_mathop(floor)(r * (u - l + 1)) + l); /* [l, u] */
			break;
		}
		default:
			return luaL_error(L, "wrong number of arguments");
	}
	return 1;
}

static int math_randomseed(lua_State *L)
{
	srand(luaL_checkunsigned(L, 1));
	(void)rand(); /* discard first value to avoid undesirable correlations */
	return 0;
}

static const luaL_Reg mathlib[] = {
	{"abs", math_abs},
	{"acos", math_acos},
	{"asin", math_asin},
	{"atan2", math_atan2},
	{"atan", math_atan},
	{"ceil", math_ceil},
	{"cosh", math_cosh},
	{"cos", math_cos},
	{"deg", math_deg},
	{"exp", math_exp},
	{"floor", math_floor},
	{"fmod", math_fmod},
	{"frexp", math_frexp},
	{"ldexp", math_ldexp},
#if defined(LUA_COMPAT_LOG10)
	{"log10", math_log10},
#endif
	{"log", math_log},
	{"max", math_max},
	{"min", math_min},
	{"modf", math_modf},
	{"pow", math_pow},
	{"rad", math_rad},
	{"random", math_random},
	{"randomseed", math_randomseed},
	{"sinh", math_sinh},
	{"sin", math_sin},
	{"sqrt", math_sqrt},
	{"tanh", math_tanh},
	{"tan", math_tan},
	{NULL, NULL}};

/*
** Open math library
*/
LUAMOD_API int luaopen_math(lua_State *L)
{
	luaL_newlib(L, mathlib);
	lua_pushnumber(L, PI);
	lua_setfield(L, -2, "pi");
	lua_pushnumber(L, HUGE_VAL);
	lua_setfield(L, -2, "huge");
	return 1;
}
