text: /*
  ** $Id: lmathlib.c,v 1.67 2005/08/26 17:36:32 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 (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;
  }
  
  