# lmathlib.c (5.3.5)

```/*
** \$Id: lmathlib.c,v 1.119.1.1 2017/04/19 17:20:42 roberto Exp \$
** Standard mathematical library
** See Copyright Notice in lua.h
*/

#define lmathlib_c
#define LUA_LIB

#include "lprefix.h"

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

#include "lua.h"

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

#undef PI
#define PI      (l_mathop(3.141592653589793238462643383279502884))

#if !defined(l_rand)            /* { */
#if defined(LUA_USE_POSIX)
#define l_rand()        random()
#define l_srand(x)      srandom(x)
#define L_RANDMAX       2147483647      /* (2^31 - 1), following POSIX */
#else
#define l_rand()        rand()
#define l_srand(x)      srand(x)
#define L_RANDMAX       RAND_MAX
#endif
#endif                          /* } */

static int math_abs (lua_State *L) {
if (lua_isinteger(L, 1)) {
lua_Integer n = lua_tointeger(L, 1);
if (n < 0) n = (lua_Integer)(0u - (lua_Unsigned)n);
lua_pushinteger(L, n);
}
else
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_cos (lua_State *L) {
lua_pushnumber(L, l_mathop(cos)(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_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_Number y = luaL_checknumber(L, 1);
lua_Number x = luaL_optnumber(L, 2, 1);
lua_pushnumber(L, l_mathop(atan2)(y, x));
return 1;
}

static int math_toint (lua_State *L) {
int valid;
lua_Integer n = lua_tointegerx(L, 1, &valid);
if (valid)
lua_pushinteger(L, n);
else {
luaL_checkany(L, 1);
lua_pushnil(L);  /* value is not convertible to integer */
}
return 1;
}

static void pushnumint (lua_State *L, lua_Number d) {
lua_Integer n;
if (lua_numbertointeger(d, &n))  /* does 'd' fit in an integer? */
lua_pushinteger(L, n);  /* result is integer */
else
lua_pushnumber(L, d);  /* result is float */
}

static int math_floor (lua_State *L) {
if (lua_isinteger(L, 1))
lua_settop(L, 1);  /* integer is its own floor */
else {
lua_Number d = l_mathop(floor)(luaL_checknumber(L, 1));
pushnumint(L, d);
}
return 1;
}

static int math_ceil (lua_State *L) {
if (lua_isinteger(L, 1))
lua_settop(L, 1);  /* integer is its own ceil */
else {
lua_Number d = l_mathop(ceil)(luaL_checknumber(L, 1));
pushnumint(L, d);
}
return 1;
}

static int math_fmod (lua_State *L) {
if (lua_isinteger(L, 1) && lua_isinteger(L, 2)) {
lua_Integer d = lua_tointeger(L, 2);
if ((lua_Unsigned)d + 1u <= 1u) {  /* special cases: -1 or 0 */
luaL_argcheck(L, d != 0, 2, "zero");
lua_pushinteger(L, 0);  /* avoid overflow with 0x80000... / -1 */
}
else
lua_pushinteger(L, lua_tointeger(L, 1) % d);
}
else
lua_pushnumber(L, l_mathop(fmod)(luaL_checknumber(L, 1),
luaL_checknumber(L, 2)));
return 1;
}

/*
** next function does not use 'modf', avoiding problems with 'double*'
** (which is not compatible with 'float*') when lua_Number is not
** 'double'.
*/
static int math_modf (lua_State *L) {
if (lua_isinteger(L ,1)) {
lua_settop(L, 1);  /* number is its own integer part */
lua_pushnumber(L, 0);  /* no fractional part */
}
else {
lua_Number n = luaL_checknumber(L, 1);
/* integer part (rounds toward zero) */
lua_Number ip = (n < 0) ? l_mathop(ceil)(n) : l_mathop(floor)(n);
pushnumint(L, ip);
/* fractional part (test needed for inf/-inf) */
lua_pushnumber(L, (n == ip) ? l_mathop(0.0) : (n - ip));
}
return 2;
}

static int math_sqrt (lua_State *L) {
lua_pushnumber(L, l_mathop(sqrt)(luaL_checknumber(L, 1)));
return 1;
}

static int math_ult (lua_State *L) {
lua_Integer a = luaL_checkinteger(L, 1);
lua_Integer b = luaL_checkinteger(L, 2);
lua_pushboolean(L, (lua_Unsigned)a < (lua_Unsigned)b);
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 !defined(LUA_USE_C89)
if (base == l_mathop(2.0))
res = l_mathop(log2)(x); else
#endif
if (base == l_mathop(10.0))
res = l_mathop(log10)(x);
else
res = l_mathop(log)(x)/l_mathop(log)(base);
}
lua_pushnumber(L, res);
return 1;
}

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) * (l_mathop(180.0) / PI));
return 1;
}

static int math_rad (lua_State *L) {
lua_pushnumber(L, luaL_checknumber(L, 1) * (PI / l_mathop(180.0)));
return 1;
}

static int math_min (lua_State *L) {
int n = lua_gettop(L);  /* number of arguments */
int imin = 1;  /* index of current minimum value */
int i;
luaL_argcheck(L, n >= 1, 1, "value expected");
for (i = 2; i <= n; i++) {
if (lua_compare(L, i, imin, LUA_OPLT))
imin = i;
}
lua_pushvalue(L, imin);
return 1;
}

static int math_max (lua_State *L) {
int n = lua_gettop(L);  /* number of arguments */
int imax = 1;  /* index of current maximum value */
int i;
luaL_argcheck(L, n >= 1, 1, "value expected");
for (i = 2; i <= n; i++) {
if (lua_compare(L, imax, i, LUA_OPLT))
imax = i;
}
lua_pushvalue(L, imax);
return 1;
}

/*
** This function uses 'double' (instead of 'lua_Number') to ensure that
** all bits from 'l_rand' can be represented, and that 'RANDMAX + 1.0'
** will keep full precision (ensuring that 'r' is always less than 1.0.)
*/
static int math_random (lua_State *L) {
lua_Integer low, up;
double r = (double)l_rand() * (1.0 / ((double)L_RANDMAX + 1.0));
switch (lua_gettop(L)) {  /* check number of arguments */
case 0: {  /* no arguments */
lua_pushnumber(L, (lua_Number)r);  /* Number between 0 and 1 */
return 1;
}
case 1: {  /* only upper limit */
low = 1;
up = luaL_checkinteger(L, 1);
break;
}
case 2: {  /* lower and upper limits */
low = luaL_checkinteger(L, 1);
up = luaL_checkinteger(L, 2);
break;
}
default: return luaL_error(L, "wrong number of arguments");
}
/* random integer in the interval [low, up] */
luaL_argcheck(L, low <= up, 1, "interval is empty");
luaL_argcheck(L, low >= 0 || up <= LUA_MAXINTEGER + low, 1,
"interval too large");
r *= (double)(up - low) + 1.0;
lua_pushinteger(L, (lua_Integer)r + low);
return 1;
}

static int math_randomseed (lua_State *L) {
l_srand((unsigned int)(lua_Integer)luaL_checknumber(L, 1));
(void)l_rand(); /* discard first value to avoid undesirable correlations */
return 0;
}

static int math_type (lua_State *L) {
if (lua_type(L, 1) == LUA_TNUMBER) {
if (lua_isinteger(L, 1))
lua_pushliteral(L, "integer");
else
lua_pushliteral(L, "float");
}
else {
luaL_checkany(L, 1);
lua_pushnil(L);
}
return 1;
}

/*
** {==================================================================
** Deprecated functions (for compatibility only)
** ===================================================================
*/
#if defined(LUA_COMPAT_MATHLIB)

static int math_cosh (lua_State *L) {
lua_pushnumber(L, l_mathop(cosh)(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_tanh (lua_State *L) {
lua_pushnumber(L, l_mathop(tanh)(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_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 = (int)luaL_checkinteger(L, 2);
lua_pushnumber(L, l_mathop(ldexp)(x, ep));
return 1;
}

static int math_log10 (lua_State *L) {
lua_pushnumber(L, l_mathop(log10)(luaL_checknumber(L, 1)));
return 1;
}

#endif
/* }================================================================== */

static const luaL_Reg mathlib[] = {
{"abs",   math_abs},
{"acos",  math_acos},
{"asin",  math_asin},
{"atan",  math_atan},
{"ceil",  math_ceil},
{"cos",   math_cos},
{"deg",   math_deg},
{"exp",   math_exp},
{"tointeger", math_toint},
{"floor", math_floor},
{"fmod",   math_fmod},
{"ult",   math_ult},
{"log",   math_log},
{"max",   math_max},
{"min",   math_min},
{"modf",   math_modf},
{"random",     math_random},
{"randomseed", math_randomseed},
{"sin",   math_sin},
{"sqrt",  math_sqrt},
{"tan",   math_tan},
{"type", math_type},
#if defined(LUA_COMPAT_MATHLIB)
{"atan2", math_atan},
{"cosh",   math_cosh},
{"sinh",   math_sinh},
{"tanh",   math_tanh},
{"pow",   math_pow},
{"frexp", math_frexp},
{"ldexp", math_ldexp},
{"log10", math_log10},
#endif
/* placeholders */
{"pi", NULL},
{"huge", NULL},
{"maxinteger", NULL},
{"mininteger", NULL},
{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, (lua_Number)HUGE_VAL);
lua_setfield(L, -2, "huge");
lua_pushinteger(L, LUA_MAXINTEGER);
lua_setfield(L, -2, "maxinteger");
lua_pushinteger(L, LUA_MININTEGER);
lua_setfield(L, -2, "mininteger");
return 1;
}

```