/*
** $Id: lmathlib.c,v 1.67.1.1 2007/12/27 13:02:25 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 (3.14159265358979323846)
#define RADIANS_PER_DEGREE (PI / 180.0)

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

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

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

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

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

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

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

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

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

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

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

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

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

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

static int math_modf(lua_State *L)
{
    double ip;
    double fp = 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, sqrt(luaL_checknumber(L, 1)));
    return 1;
}

static int math_pow(lua_State *L)
{
    lua_pushnumber(L, pow(luaL_checknumber(L, 1), luaL_checknumber(L, 2)));
    return 1;
}

static int math_log(lua_State *L)
{
    lua_pushnumber(L, log(luaL_checknumber(L, 1)));
    return 1;
}

static int math_log10(lua_State *L)
{
    lua_pushnumber(L, log10(luaL_checknumber(L, 1)));
    return 1;
}

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

static int math_ldexp(lua_State *L)
{
    lua_pushnumber(L, ldexp(luaL_checknumber(L, 1), luaL_checkint(L, 2)));
    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 */
        int u = luaL_checkint(L, 1);
        luaL_argcheck(L, 1 <= u, 1, "interval is empty");
        lua_pushnumber(L, floor(r * u) + 1); /* int between 1 and `u' */
        break;
    }
    case 2: { /* lower and upper limits */
        int l = luaL_checkint(L, 1);
        int u = luaL_checkint(L, 2);
        luaL_argcheck(L, l <= u, 2, "interval is empty");
        lua_pushnumber(L, floor(r * (u - l + 1)) +
                              l); /* int between `l' and `u' */
        break;
    }
    default:
        return luaL_error(L, "wrong number of arguments");
    }
    return 1;
}

static int math_randomseed(lua_State *L)
{
    srand(luaL_checkint(L, 1));
    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},
                                   {"log10", math_log10},
                                   {"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
*/
LUALIB_API int luaopen_math(lua_State *L)
{
    luaL_register(L, LUA_MATHLIBNAME, mathlib);
    lua_pushnumber(L, PI);
    lua_setfield(L, -2, "pi");
    lua_pushnumber(L, HUGE_VAL);
    lua_setfield(L, -2, "huge");
#if defined(LUA_COMPAT_MOD)
    lua_getfield(L, -1, "fmod");
    lua_setfield(L, -2, "mod");
#endif
    return 1;
}
