/*
** $Id: lmathlib.c,v 1.83 2013/03/07 18:21:32 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;
}

