/*
** $Id: lmathlib.c,v 1.16 1999/02/19 17:33:35 roberto Exp roberto $
** Lua standard mathematical library
** See Copyright Notice in lua.h
*/


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

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


#undef PI
#define PI	(3.14159265358979323846)
#define RADIANS_PER_DEGREE	(PI/180.0)


/*
** If you want Lua to operate in radians (instead of degrees),
** define RADIANS
*/
#ifdef RADIANS
#define FROMRAD(a)	(a)
#define TORAD(a)	(a)
#else
#define FROMRAD(a)	((a)/RADIANS_PER_DEGREE)
#define TORAD(a)	((a)*RADIANS_PER_DEGREE)
#endif


static void math_abs (void) {
  lua_pushnumber(fabs(luaL_check_number(1)));
}

static void math_sin (void) {
  lua_pushnumber(sin(TORAD(luaL_check_number(1))));
}

static void math_cos (void) {
  lua_pushnumber(cos(TORAD(luaL_check_number(1))));
}

static void math_tan (void) {
  lua_pushnumber(tan(TORAD(luaL_check_number(1))));
}

static void math_asin (void) {
  lua_pushnumber(FROMRAD(asin(luaL_check_number(1))));
}

static void math_acos (void) {
  lua_pushnumber(FROMRAD(acos(luaL_check_number(1))));
}

static void math_atan (void) {
  lua_pushnumber(FROMRAD(atan(luaL_check_number(1))));
}

static void math_atan2 (void) {
  lua_pushnumber(FROMRAD(atan2(luaL_check_number(1), luaL_check_number(2))));
}

static void math_ceil (void) {
  lua_pushnumber(ceil(luaL_check_number(1)));
}

static void math_floor (void) {
  lua_pushnumber(floor(luaL_check_number(1)));
}

static void math_mod (void) {
  lua_pushnumber(fmod(luaL_check_number(1), luaL_check_number(2)));
}

static void math_sqrt (void) {
  lua_pushnumber(sqrt(luaL_check_number(1)));
}

static void math_pow (void) {
  lua_pushnumber(pow(luaL_check_number(1), luaL_check_number(2)));
}

static void math_log (void) {
  lua_pushnumber(log(luaL_check_number(1)));
}

static void math_log10 (void) {
  lua_pushnumber(log10(luaL_check_number(1)));
}

static void math_exp (void) {
  lua_pushnumber(exp(luaL_check_number(1)));
}

static void math_deg (void) {
  lua_pushnumber(luaL_check_number(1)/RADIANS_PER_DEGREE);
}

static void math_rad (void) {
  lua_pushnumber(luaL_check_number(1)*RADIANS_PER_DEGREE);
}

static void math_frexp (void) {
  int e;
  lua_pushnumber(frexp(luaL_check_number(1), &e));
  lua_pushnumber(e);
}

static void math_ldexp (void) {
  lua_pushnumber(ldexp(luaL_check_number(1), luaL_check_int(2)));
}


static void math_min (void) {
  int i = 1;
  double dmin = luaL_check_number(i);
  while (lua_getparam(++i) != LUA_NOOBJECT) {
    double d = luaL_check_number(i);
    if (d < dmin)
      dmin = d;
  }
  lua_pushnumber(dmin);
}


static void math_max (void) {
  int i = 1;
  double dmax = luaL_check_number(i);
  while (lua_getparam(++i) != LUA_NOOBJECT) {
    double d = luaL_check_number(i);
    if (d > dmax)
      dmax = d;
  }
  lua_pushnumber(dmax);
}


static void math_random (void) {
  /* the '%' avoids the (rare) case of r==1, and is needed also because on
     some systems (SunOS!) "rand()" may return a value bigger than RAND_MAX */
  double r = (double)(rand()%RAND_MAX) / (double)RAND_MAX;
  int l = luaL_opt_int(1, 0);
  if (l == 0)
    lua_pushnumber(r);
  else {
    int u = luaL_opt_int(2, 0);
    if (u == 0) {
      u = l;
      l = 1;
    }
    luaL_arg_check(l<=u, 1, "interval is empty");
    lua_pushnumber((int)(r*(u-l+1))+l);
  }
}


static void math_randomseed (void) {
  srand(luaL_check_int(1));
}


static struct luaL_reg mathlib[] = {
{"abs",   math_abs},
{"sin",   math_sin},
{"cos",   math_cos},
{"tan",   math_tan},
{"asin",  math_asin},
{"acos",  math_acos},
{"atan",  math_atan},
{"atan2", math_atan2},
{"ceil",  math_ceil},
{"floor", math_floor},
{"mod",   math_mod},
{"frexp", math_frexp},
{"ldexp", math_ldexp},
{"sqrt",  math_sqrt},
{"min",   math_min},
{"max",   math_max},
{"log",   math_log},
{"log10", math_log10},
{"exp",   math_exp},
{"deg",   math_deg},
{"rad",   math_rad},
{"random",     math_random},
{"randomseed", math_randomseed}
};

/*
** Open math library
*/
void lua_mathlibopen (void) {
  luaL_openlib(mathlib, (sizeof(mathlib)/sizeof(mathlib[0])));
  lua_pushcfunction(math_pow);
  lua_pushnumber(0);  /* to get its tag */
  lua_settagmethod(lua_tag(lua_pop()), "pow");
  lua_pushnumber(PI); lua_setglobal("PI");
}