/*
** $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))
#define DEGREES_PER_RADIAN	((lua_Number)180.0/PI)


static int math_abs (lua_State *L) {
  /* Was: lua_pushnumber(L, fabs(luaL_checknumber(L, 1))); */
  lua_Number n = luaL_checknumber(L, 1);
  lua_pushnumber(L, n < 0 ? -n : n);
  return 1;
}

#if 0
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;
}
#endif

static int math_ceil (lua_State *L) {
  /* Doesn't change anything in fixed point arithmetic */
  lua_pushnumber(L, luaL_checknumber(L, 1));
  return 1;
}

static int math_floor (lua_State *L) {
  /* Doesn't change anything in fixed point arithmetic */
  lua_pushnumber(L, luaL_checknumber(L, 1));
  return 1;
}

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

#if 0
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;
}
#endif
static int math_deg (lua_State *L) {
  lua_pushnumber(L, luaL_checknumber(L, 1)*DEGREES_PER_RADIAN);
  return 1;
}

static int math_rad (lua_State *L) {
  lua_pushnumber(L, (luaL_checknumber(L, 1)*100)/(DEGREES_PER_RADIAN*100));
  return 1;
}

#if 0
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;
}
#endif


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) {
  /* We're not SunOS */
  lua_Number r = (lua_Number)(rb->rand());
  switch (lua_gettop(L)) {  /* check number of arguments */
    case 0: {  /* no arguments */
      lua_pushnumber(L, r);  /* Number between 0 and RAND_MAX */
      break;
    }
    case 1: {  /* only upper limit */
      lua_Number u = luaL_checknumber(L, 1);
      luaL_argcheck(L, 1 <= u, 1, "interval is empty");
      lua_pushnumber(L, r%u+1);  /* int between 1 and `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, 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) {
  rb->srand(luaL_checkunsigned(L, 1));
  return 0;
}


static const luaL_Reg mathlib[] = {
  {"abs",   math_abs},
#if 0
  {"acos",  math_acos},
  {"asin",  math_asin},
  {"atan2", math_atan2},
  {"atan",  math_atan},
#endif
  {"ceil",  math_ceil},
#if 0
  {"cosh",  math_cosh},
  {"cos",   math_cos},
#endif
  {"deg",   math_deg},
#if 0
  {"exp",   math_exp},
#endif
  {"floor", math_floor},
  {"fmod",  math_fmod},
#if 0
  {"frexp", math_frexp},
  {"ldexp", math_ldexp},
#if defined(LUA_COMPAT_LOG10)
  {"log10", math_log10},
#endif
  {"log",   math_log},
#endif
  {"max",   math_max},
  {"min",   math_min},
#if 0
  {"modf",  math_modf},
  {"pow",   math_pow},
#endif
  {"rad",   math_rad},
  {"random",     math_random},
  {"randomseed", math_randomseed},
#if 0
  {"sinh",  math_sinh},
  {"sin",   math_sin},
  {"sqrt",  math_sqrt},
  {"tanh",   math_tanh},
  {"tan",   math_tan},
#endif
  {NULL, NULL}
};


/*
** Open math library
*/
LUAMOD_API int luaopen_math (lua_State *L) {
  luaL_newlib(L, mathlib);
#if 0 /* No use in adding floating point constants when there's no FP */
  lua_pushnumber(L, PI);
  lua_setfield(L, -2, "pi");
  lua_pushnumber(L, HUGE_VAL);
  lua_setfield(L, -2, "huge");
#endif
  return 1;
}