/*
** $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 <stdint.h> // For RadioGatun[32]
#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;
}

uint32_t rg_belt[40], rg_mill[19], rg_phase = 0, rg_place = 0, rg_num = 0;
#define rg uint32_t // NO WARRANTY
#define rgp(a) for(c=0;c<a;c++)
#define rgn w[c*13]^=s;u[16+c]^=s;
void rgf(rg*a,rg*b){rg m=19,A[45],x,o=13,c,y,r=0;rgp(12)b[c+c%3*o]^=a
[c+1];rgp(m){r=(c+r)&31;y=c*7;x=a[y++%m];x^=a[y%m]|~a[(y+1)%m];A[c]=A
[c+m]=x>>r|x<<(32-r)%32;}for(y=39;y--;b[y+1]=b[y])a[y%m]=A[y]^A[y+1]^
A[y+4];*a^=1;rgp(3)a[c+o]^=b[c*o]=b[c*o+o];}
void rgl(rg*u,rg*w,const char*v){rg s,q,c,x;rgp(40)w[c]=u[c%19]=0;for
(;;rgf(u,w)){rgp(3){for(s=q=0;q<4;){x=*v++;s|=(x?255&x:1)<<8*q++;if(!
x){rgn;rgp(17)rgf(u,w);return;}}rgn;}}}
rg rgi(rg*m,rg*b,rg*a){if(*a&2)rgf(m,b);return m[*a^=3];}

// This is used so we can get ints directly from RadioGatun.  They are 16
// bits in size because 32-bit floats have 24 bits of percision, and it's
// a lot simpler to get 16 bits from rg32 instead of 24 bits
static int math_rand16 (lua_State *L) {
  if(rg_phase == 0) {
    rgl(rg_mill, rg_belt, "1234");
    rg_phase = 2;
  }
  if(rg_place == 0) {
    rg_num = rgi(rg_mill, rg_belt, &rg_phase);
    // Fix endian; swap 16-bit parts
    rg_num = ((rg_num & 0xff) << 8 | (rg_num & 0xff00) >> 8 |
              (rg_num & 0xff0000) << 8 | (rg_num & 0xff000000) >> 8);
    rg_place = 1;
  } else {
    rg_num >>= 16;
    rg_place = 0;
  }
  lua_Number r = (lua_Number)(rg_num & 0xffff);
  lua_pushnumber(L, r);  /* Number between 0 and 1 */
  return 1;
}


static int math_random (lua_State *L) {
  if(rg_phase == 0) {
    rgl(rg_mill, rg_belt, "1234");
    rg_phase = 2;
  }
  /* 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)(rgi(rg_mill, rg_belt, &rg_phase)%0x7fffffff)
      / (lua_Number)2147483648.0;
  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) {
  const char *the_seed = luaL_checkstring(L,1);
  rgl(rg_mill, rg_belt, the_seed);
  rg_phase = 2;
  rg_place = 0;
  rg_num = 0;
  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},
  {"rand16",     math_rand16},
  {"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;
}