1/*	$NetBSD: lmathlib.c,v 1.11 2023/06/08 21:12:08 nikita Exp $	*/
2
3/*
4** Id: lmathlib.c
5** Standard mathematical library
6** See Copyright Notice in lua.h
7*/
8
9#define lmathlib_c
10#define LUA_LIB
11
12#include "lprefix.h"
13
14
15#include <float.h>
16#include <limits.h>
17#include <math.h>
18#include <stdlib.h>
19#include <time.h>
20
21#include "lua.h"
22
23#include "lauxlib.h"
24#include "lualib.h"
25
26
27#undef PI
28#define PI	(l_mathop(3.141592653589793238462643383279502884))
29
30
31static int math_abs (lua_State *L) {
32  if (lua_isinteger(L, 1)) {
33    lua_Integer n = lua_tointeger(L, 1);
34    if (n < 0) n = (lua_Integer)(0u - (lua_Unsigned)n);
35    lua_pushinteger(L, n);
36  }
37  else
38    lua_pushnumber(L, l_mathop(fabs)(luaL_checknumber(L, 1)));
39  return 1;
40}
41
42static int math_sin (lua_State *L) {
43  lua_pushnumber(L, l_mathop(sin)(luaL_checknumber(L, 1)));
44  return 1;
45}
46
47static int math_cos (lua_State *L) {
48  lua_pushnumber(L, l_mathop(cos)(luaL_checknumber(L, 1)));
49  return 1;
50}
51
52static int math_tan (lua_State *L) {
53  lua_pushnumber(L, l_mathop(tan)(luaL_checknumber(L, 1)));
54  return 1;
55}
56
57static int math_asin (lua_State *L) {
58  lua_pushnumber(L, l_mathop(asin)(luaL_checknumber(L, 1)));
59  return 1;
60}
61
62static int math_acos (lua_State *L) {
63  lua_pushnumber(L, l_mathop(acos)(luaL_checknumber(L, 1)));
64  return 1;
65}
66
67static int math_atan (lua_State *L) {
68  lua_Number y = luaL_checknumber(L, 1);
69  lua_Number x = luaL_optnumber(L, 2, 1);
70  lua_pushnumber(L, l_mathop(atan2)(y, x));
71  return 1;
72}
73
74
75static int math_toint (lua_State *L) {
76  int valid;
77  lua_Integer n = lua_tointegerx(L, 1, &valid);
78  if (l_likely(valid))
79    lua_pushinteger(L, n);
80  else {
81    luaL_checkany(L, 1);
82    luaL_pushfail(L);  /* value is not convertible to integer */
83  }
84  return 1;
85}
86
87
88static void pushnumint (lua_State *L, lua_Number d) {
89  lua_Integer n;
90  if (lua_numbertointeger(d, &n))  /* does 'd' fit in an integer? */
91    lua_pushinteger(L, n);  /* result is integer */
92  else
93    lua_pushnumber(L, d);  /* result is float */
94}
95
96
97static int math_floor (lua_State *L) {
98  if (lua_isinteger(L, 1))
99    lua_settop(L, 1);  /* integer is its own floor */
100  else {
101    lua_Number d = l_mathop(floor)(luaL_checknumber(L, 1));
102    pushnumint(L, d);
103  }
104  return 1;
105}
106
107
108static int math_ceil (lua_State *L) {
109  if (lua_isinteger(L, 1))
110    lua_settop(L, 1);  /* integer is its own ceil */
111  else {
112    lua_Number d = l_mathop(ceil)(luaL_checknumber(L, 1));
113    pushnumint(L, d);
114  }
115  return 1;
116}
117
118
119static int math_fmod (lua_State *L) {
120  if (lua_isinteger(L, 1) && lua_isinteger(L, 2)) {
121    lua_Integer d = lua_tointeger(L, 2);
122    if ((lua_Unsigned)d + 1u <= 1u) {  /* special cases: -1 or 0 */
123      luaL_argcheck(L, d != 0, 2, "zero");
124      lua_pushinteger(L, 0);  /* avoid overflow with 0x80000... / -1 */
125    }
126    else
127      lua_pushinteger(L, lua_tointeger(L, 1) % d);
128  }
129  else
130    lua_pushnumber(L, l_mathop(fmod)(luaL_checknumber(L, 1),
131                                     luaL_checknumber(L, 2)));
132  return 1;
133}
134
135
136/*
137** next function does not use 'modf', avoiding problems with 'double*'
138** (which is not compatible with 'float*') when lua_Number is not
139** 'double'.
140*/
141static int math_modf (lua_State *L) {
142  if (lua_isinteger(L ,1)) {
143    lua_settop(L, 1);  /* number is its own integer part */
144    lua_pushnumber(L, 0);  /* no fractional part */
145  }
146  else {
147    lua_Number n = luaL_checknumber(L, 1);
148    /* integer part (rounds toward zero) */
149    lua_Number ip = (n < 0) ? l_mathop(ceil)(n) : l_mathop(floor)(n);
150    pushnumint(L, ip);
151    /* fractional part (test needed for inf/-inf) */
152    lua_pushnumber(L, (n == ip) ? l_mathop(0.0) : (n - ip));
153  }
154  return 2;
155}
156
157
158static int math_sqrt (lua_State *L) {
159  lua_pushnumber(L, l_mathop(sqrt)(luaL_checknumber(L, 1)));
160  return 1;
161}
162
163
164static int math_ult (lua_State *L) {
165  lua_Integer a = luaL_checkinteger(L, 1);
166  lua_Integer b = luaL_checkinteger(L, 2);
167  lua_pushboolean(L, (lua_Unsigned)a < (lua_Unsigned)b);
168  return 1;
169}
170
171static int math_log (lua_State *L) {
172  lua_Number x = luaL_checknumber(L, 1);
173  lua_Number res;
174  if (lua_isnoneornil(L, 2))
175    res = l_mathop(log)(x);
176  else {
177    lua_Number base = luaL_checknumber(L, 2);
178#if !defined(LUA_USE_C89)
179    if (base == l_mathop(2.0))
180      res = l_mathop(log2)(x);
181    else
182#endif
183    if (base == l_mathop(10.0))
184      res = l_mathop(log10)(x);
185    else
186      res = l_mathop(log)(x)/l_mathop(log)(base);
187  }
188  lua_pushnumber(L, res);
189  return 1;
190}
191
192static int math_exp (lua_State *L) {
193  lua_pushnumber(L, l_mathop(exp)(luaL_checknumber(L, 1)));
194  return 1;
195}
196
197static int math_deg (lua_State *L) {
198  lua_pushnumber(L, luaL_checknumber(L, 1) * (l_mathop(180.0) / PI));
199  return 1;
200}
201
202static int math_rad (lua_State *L) {
203  lua_pushnumber(L, luaL_checknumber(L, 1) * (PI / l_mathop(180.0)));
204  return 1;
205}
206
207
208static int math_min (lua_State *L) {
209  int n = lua_gettop(L);  /* number of arguments */
210  int imin = 1;  /* index of current minimum value */
211  int i;
212  luaL_argcheck(L, n >= 1, 1, "value expected");
213  for (i = 2; i <= n; i++) {
214    if (lua_compare(L, i, imin, LUA_OPLT))
215      imin = i;
216  }
217  lua_pushvalue(L, imin);
218  return 1;
219}
220
221
222static int math_max (lua_State *L) {
223  int n = lua_gettop(L);  /* number of arguments */
224  int imax = 1;  /* index of current maximum value */
225  int i;
226  luaL_argcheck(L, n >= 1, 1, "value expected");
227  for (i = 2; i <= n; i++) {
228    if (lua_compare(L, imax, i, LUA_OPLT))
229      imax = i;
230  }
231  lua_pushvalue(L, imax);
232  return 1;
233}
234
235
236static int math_type (lua_State *L) {
237  if (lua_type(L, 1) == LUA_TNUMBER)
238    lua_pushstring(L, (lua_isinteger(L, 1)) ? "integer" : "float");
239  else {
240    luaL_checkany(L, 1);
241    luaL_pushfail(L);
242  }
243  return 1;
244}
245
246
247
248/*
249** {==================================================================
250** Pseudo-Random Number Generator based on 'xoshiro256**'.
251** ===================================================================
252*/
253
254/* number of binary digits in the mantissa of a float */
255#define FIGS	l_floatatt(MANT_DIG)
256
257#if FIGS > 64
258/* there are only 64 random bits; use them all */
259#undef FIGS
260#define FIGS	64
261#endif
262
263
264/*
265** LUA_RAND32 forces the use of 32-bit integers in the implementation
266** of the PRN generator (mainly for testing).
267*/
268#if !defined(LUA_RAND32) && !defined(Rand64)
269
270/* try to find an integer type with at least 64 bits */
271
272#if ((ULONG_MAX >> 31) >> 31) >= 3
273
274/* 'long' has at least 64 bits */
275#define Rand64		unsigned long
276
277#elif !defined(LUA_USE_C89) && defined(LLONG_MAX)
278
279/* there is a 'long long' type (which must have at least 64 bits) */
280#define Rand64		unsigned long long
281
282#elif ((LUA_MAXUNSIGNED >> 31) >> 31) >= 3
283
284/* 'lua_Unsigned' has at least 64 bits */
285#define Rand64		lua_Unsigned
286
287#endif
288
289#endif
290
291
292#if defined(Rand64)  /* { */
293
294/*
295** Standard implementation, using 64-bit integers.
296** If 'Rand64' has more than 64 bits, the extra bits do not interfere
297** with the 64 initial bits, except in a right shift. Moreover, the
298** final result has to discard the extra bits.
299*/
300
301/* avoid using extra bits when needed */
302#define trim64(x)	((x) & 0xffffffffffffffffu)
303
304
305/* rotate left 'x' by 'n' bits */
306static Rand64 rotl (Rand64 x, int n) {
307  return (x << n) | (trim64(x) >> (64 - n));
308}
309
310static Rand64 nextrand (Rand64 *state) {
311  Rand64 state0 = state[0];
312  Rand64 state1 = state[1];
313  Rand64 state2 = state[2] ^ state0;
314  Rand64 state3 = state[3] ^ state1;
315  Rand64 res = rotl(state1 * 5, 7) * 9;
316  state[0] = state0 ^ state3;
317  state[1] = state1 ^ state2;
318  state[2] = state2 ^ (state1 << 17);
319  state[3] = rotl(state3, 45);
320  return res;
321}
322
323
324/* must take care to not shift stuff by more than 63 slots */
325
326
327/*
328** Convert bits from a random integer into a float in the
329** interval [0,1), getting the higher FIG bits from the
330** random unsigned integer and converting that to a float.
331*/
332
333/* must throw out the extra (64 - FIGS) bits */
334#define shift64_FIG	(64 - FIGS)
335
336/* to scale to [0, 1), multiply by scaleFIG = 2^(-FIGS) */
337#define scaleFIG	(l_mathop(0.5) / ((Rand64)1 << (FIGS - 1)))
338
339static lua_Number I2d (Rand64 x) {
340  return (lua_Number)(trim64(x) >> shift64_FIG) * scaleFIG;
341}
342
343/* convert a 'Rand64' to a 'lua_Unsigned' */
344#define I2UInt(x)	((lua_Unsigned)trim64(x))
345
346/* convert a 'lua_Unsigned' to a 'Rand64' */
347#define Int2I(x)	((Rand64)(x))
348
349
350#else	/* no 'Rand64'   }{ */
351
352/* get an integer with at least 32 bits */
353#if LUAI_IS32INT
354typedef unsigned int lu_int32;
355#else
356typedef unsigned long lu_int32;
357#endif
358
359
360/*
361** Use two 32-bit integers to represent a 64-bit quantity.
362*/
363typedef struct Rand64 {
364  lu_int32 h;  /* higher half */
365  lu_int32 l;  /* lower half */
366} Rand64;
367
368
369/*
370** If 'lu_int32' has more than 32 bits, the extra bits do not interfere
371** with the 32 initial bits, except in a right shift and comparisons.
372** Moreover, the final result has to discard the extra bits.
373*/
374
375/* avoid using extra bits when needed */
376#define trim32(x)	((x) & 0xffffffffu)
377
378
379/*
380** basic operations on 'Rand64' values
381*/
382
383/* build a new Rand64 value */
384static Rand64 packI (lu_int32 h, lu_int32 l) {
385  Rand64 result;
386  result.h = h;
387  result.l = l;
388  return result;
389}
390
391/* return i << n */
392static Rand64 Ishl (Rand64 i, int n) {
393  lua_assert(n > 0 && n < 32);
394  return packI((i.h << n) | (trim32(i.l) >> (32 - n)), i.l << n);
395}
396
397/* i1 ^= i2 */
398static void Ixor (Rand64 *i1, Rand64 i2) {
399  i1->h ^= i2.h;
400  i1->l ^= i2.l;
401}
402
403/* return i1 + i2 */
404static Rand64 Iadd (Rand64 i1, Rand64 i2) {
405  Rand64 result = packI(i1.h + i2.h, i1.l + i2.l);
406  if (trim32(result.l) < trim32(i1.l))  /* carry? */
407    result.h++;
408  return result;
409}
410
411/* return i * 5 */
412static Rand64 times5 (Rand64 i) {
413  return Iadd(Ishl(i, 2), i);  /* i * 5 == (i << 2) + i */
414}
415
416/* return i * 9 */
417static Rand64 times9 (Rand64 i) {
418  return Iadd(Ishl(i, 3), i);  /* i * 9 == (i << 3) + i */
419}
420
421/* return 'i' rotated left 'n' bits */
422static Rand64 rotl (Rand64 i, int n) {
423  lua_assert(n > 0 && n < 32);
424  return packI((i.h << n) | (trim32(i.l) >> (32 - n)),
425               (trim32(i.h) >> (32 - n)) | (i.l << n));
426}
427
428/* for offsets larger than 32, rotate right by 64 - offset */
429static Rand64 rotl1 (Rand64 i, int n) {
430  lua_assert(n > 32 && n < 64);
431  n = 64 - n;
432  return packI((trim32(i.h) >> n) | (i.l << (32 - n)),
433               (i.h << (32 - n)) | (trim32(i.l) >> n));
434}
435
436/*
437** implementation of 'xoshiro256**' algorithm on 'Rand64' values
438*/
439static Rand64 nextrand (Rand64 *state) {
440  Rand64 res = times9(rotl(times5(state[1]), 7));
441  Rand64 t = Ishl(state[1], 17);
442  Ixor(&state[2], state[0]);
443  Ixor(&state[3], state[1]);
444  Ixor(&state[1], state[2]);
445  Ixor(&state[0], state[3]);
446  Ixor(&state[2], t);
447  state[3] = rotl1(state[3], 45);
448  return res;
449}
450
451
452/*
453** Converts a 'Rand64' into a float.
454*/
455
456/* an unsigned 1 with proper type */
457#define UONE		((lu_int32)1)
458
459
460#if FIGS <= 32
461
462/* 2^(-FIGS) */
463#define scaleFIG       (l_mathop(0.5) / (UONE << (FIGS - 1)))
464
465/*
466** get up to 32 bits from higher half, shifting right to
467** throw out the extra bits.
468*/
469static lua_Number I2d (Rand64 x) {
470  lua_Number h = (lua_Number)(trim32(x.h) >> (32 - FIGS));
471  return h * scaleFIG;
472}
473
474#else	/* 32 < FIGS <= 64 */
475
476/* must take care to not shift stuff by more than 31 slots */
477
478/* 2^(-FIGS) = 1.0 / 2^30 / 2^3 / 2^(FIGS-33) */
479#define scaleFIG  \
480    (l_mathop(1.0) / (UONE << 30) / l_mathop(8.0) / (UONE << (FIGS - 33)))
481
482/*
483** use FIGS - 32 bits from lower half, throwing out the other
484** (32 - (FIGS - 32)) = (64 - FIGS) bits
485*/
486#define shiftLOW	(64 - FIGS)
487
488/*
489** higher 32 bits go after those (FIGS - 32) bits: shiftHI = 2^(FIGS - 32)
490*/
491#define shiftHI		((lua_Number)(UONE << (FIGS - 33)) * l_mathop(2.0))
492
493
494static lua_Number I2d (Rand64 x) {
495  lua_Number h = (lua_Number)trim32(x.h) * shiftHI;
496  lua_Number l = (lua_Number)(trim32(x.l) >> shiftLOW);
497  return (h + l) * scaleFIG;
498}
499
500#endif
501
502
503/* convert a 'Rand64' to a 'lua_Unsigned' */
504static lua_Unsigned I2UInt (Rand64 x) {
505  return (((lua_Unsigned)trim32(x.h) << 31) << 1) | (lua_Unsigned)trim32(x.l);
506}
507
508/* convert a 'lua_Unsigned' to a 'Rand64' */
509static Rand64 Int2I (lua_Unsigned n) {
510  return packI((lu_int32)((n >> 31) >> 1), (lu_int32)n);
511}
512
513#endif  /* } */
514
515
516/*
517** A state uses four 'Rand64' values.
518*/
519typedef struct {
520  Rand64 s[4];
521} RanState;
522
523
524/*
525** Project the random integer 'ran' into the interval [0, n].
526** Because 'ran' has 2^B possible values, the projection can only be
527** uniform when the size of the interval is a power of 2 (exact
528** division). Otherwise, to get a uniform projection into [0, n], we
529** first compute 'lim', the smallest Mersenne number not smaller than
530** 'n'. We then project 'ran' into the interval [0, lim].  If the result
531** is inside [0, n], we are done. Otherwise, we try with another 'ran',
532** until we have a result inside the interval.
533*/
534static lua_Unsigned project (lua_Unsigned ran, lua_Unsigned n,
535                             RanState *state) {
536  if ((n & (n + 1)) == 0)  /* is 'n + 1' a power of 2? */
537    return ran & n;  /* no bias */
538  else {
539    lua_Unsigned lim = n;
540    /* compute the smallest (2^b - 1) not smaller than 'n' */
541    lim |= (lim >> 1);
542    lim |= (lim >> 2);
543    lim |= (lim >> 4);
544    lim |= (lim >> 8);
545    lim |= (lim >> 16);
546#if (LUA_MAXUNSIGNED >> 31) >= 3
547    lim |= (lim >> 32);  /* integer type has more than 32 bits */
548#endif
549    lua_assert((lim & (lim + 1)) == 0  /* 'lim + 1' is a power of 2, */
550      && lim >= n  /* not smaller than 'n', */
551      && (lim >> 1) < n);  /* and it is the smallest one */
552    while ((ran &= lim) > n)  /* project 'ran' into [0..lim] */
553      ran = I2UInt(nextrand(state->s));  /* not inside [0..n]? try again */
554    return ran;
555  }
556}
557
558
559static int math_random (lua_State *L) {
560  lua_Integer low, up;
561  lua_Unsigned p;
562  RanState *state = (RanState *)lua_touserdata(L, lua_upvalueindex(1));
563  Rand64 rv = nextrand(state->s);  /* next pseudo-random value */
564  switch (lua_gettop(L)) {  /* check number of arguments */
565    case 0: {  /* no arguments */
566      lua_pushnumber(L, I2d(rv));  /* float between 0 and 1 */
567      return 1;
568    }
569    case 1: {  /* only upper limit */
570      low = 1;
571      up = luaL_checkinteger(L, 1);
572      if (up == 0) {  /* single 0 as argument? */
573        lua_pushinteger(L, I2UInt(rv));  /* full random integer */
574        return 1;
575      }
576      break;
577    }
578    case 2: {  /* lower and upper limits */
579      low = luaL_checkinteger(L, 1);
580      up = luaL_checkinteger(L, 2);
581      break;
582    }
583    default: return luaL_error(L, "wrong number of arguments");
584  }
585  /* random integer in the interval [low, up] */
586  luaL_argcheck(L, low <= up, 1, "interval is empty");
587  /* project random integer into the interval [0, up - low] */
588  p = project(I2UInt(rv), (lua_Unsigned)up - (lua_Unsigned)low, state);
589  lua_pushinteger(L, p + (lua_Unsigned)low);
590  return 1;
591}
592
593
594static void setseed (lua_State *L, Rand64 *state,
595                     lua_Unsigned n1, lua_Unsigned n2) {
596  int i;
597  state[0] = Int2I(n1);
598  state[1] = Int2I(0xff);  /* avoid a zero state */
599  state[2] = Int2I(n2);
600  state[3] = Int2I(0);
601  for (i = 0; i < 16; i++)
602    nextrand(state);  /* discard initial values to "spread" seed */
603  lua_pushinteger(L, n1);
604  lua_pushinteger(L, n2);
605}
606
607
608/*
609** Set a "random" seed. To get some randomness, use the current time
610** and the address of 'L' (in case the machine does address space layout
611** randomization).
612*/
613static void randseed (lua_State *L, RanState *state) {
614  lua_Unsigned seed1 = (lua_Unsigned)time(NULL);
615  lua_Unsigned seed2 = (lua_Unsigned)(size_t)L;
616  setseed(L, state->s, seed1, seed2);
617}
618
619
620static int math_randomseed (lua_State *L) {
621  RanState *state = (RanState *)lua_touserdata(L, lua_upvalueindex(1));
622  if (lua_isnone(L, 1)) {
623    randseed(L, state);
624  }
625  else {
626    lua_Integer n1 = luaL_checkinteger(L, 1);
627    lua_Integer n2 = luaL_optinteger(L, 2, 0);
628    setseed(L, state->s, n1, n2);
629  }
630  return 2;  /* return seeds */
631}
632
633
634static const luaL_Reg randfuncs[] = {
635  {"random", math_random},
636  {"randomseed", math_randomseed},
637  {NULL, NULL}
638};
639
640
641/*
642** Register the random functions and initialize their state.
643*/
644static void setrandfunc (lua_State *L) {
645  RanState *state = (RanState *)lua_newuserdatauv(L, sizeof(RanState), 0);
646  randseed(L, state);  /* initialize with a "random" seed */
647  lua_pop(L, 2);  /* remove pushed seeds */
648  luaL_setfuncs(L, randfuncs, 1);
649}
650
651/* }================================================================== */
652
653
654/*
655** {==================================================================
656** Deprecated functions (for compatibility only)
657** ===================================================================
658*/
659#if defined(LUA_COMPAT_MATHLIB)
660
661static int math_cosh (lua_State *L) {
662  lua_pushnumber(L, l_mathop(cosh)(luaL_checknumber(L, 1)));
663  return 1;
664}
665
666static int math_sinh (lua_State *L) {
667  lua_pushnumber(L, l_mathop(sinh)(luaL_checknumber(L, 1)));
668  return 1;
669}
670
671static int math_tanh (lua_State *L) {
672  lua_pushnumber(L, l_mathop(tanh)(luaL_checknumber(L, 1)));
673  return 1;
674}
675
676static int math_pow (lua_State *L) {
677  lua_Number x = luaL_checknumber(L, 1);
678  lua_Number y = luaL_checknumber(L, 2);
679  lua_pushnumber(L, l_mathop(pow)(x, y));
680  return 1;
681}
682
683static int math_frexp (lua_State *L) {
684  int e;
685  lua_pushnumber(L, l_mathop(frexp)(luaL_checknumber(L, 1), &e));
686  lua_pushinteger(L, e);
687  return 2;
688}
689
690static int math_ldexp (lua_State *L) {
691  lua_Number x = luaL_checknumber(L, 1);
692  int ep = (int)luaL_checkinteger(L, 2);
693  lua_pushnumber(L, l_mathop(ldexp)(x, ep));
694  return 1;
695}
696
697static int math_log10 (lua_State *L) {
698  lua_pushnumber(L, l_mathop(log10)(luaL_checknumber(L, 1)));
699  return 1;
700}
701
702#endif
703/* }================================================================== */
704
705
706
707static const luaL_Reg mathlib[] = {
708  {"abs",   math_abs},
709  {"acos",  math_acos},
710  {"asin",  math_asin},
711  {"atan",  math_atan},
712  {"ceil",  math_ceil},
713  {"cos",   math_cos},
714  {"deg",   math_deg},
715  {"exp",   math_exp},
716  {"tointeger", math_toint},
717  {"floor", math_floor},
718  {"fmod",   math_fmod},
719  {"ult",   math_ult},
720  {"log",   math_log},
721  {"max",   math_max},
722  {"min",   math_min},
723  {"modf",   math_modf},
724  {"rad",   math_rad},
725  {"sin",   math_sin},
726  {"sqrt",  math_sqrt},
727  {"tan",   math_tan},
728  {"type", math_type},
729#if defined(LUA_COMPAT_MATHLIB)
730  {"atan2", math_atan},
731  {"cosh",   math_cosh},
732  {"sinh",   math_sinh},
733  {"tanh",   math_tanh},
734  {"pow",   math_pow},
735  {"frexp", math_frexp},
736  {"ldexp", math_ldexp},
737  {"log10", math_log10},
738#endif
739  /* placeholders */
740  {"random", NULL},
741  {"randomseed", NULL},
742  {"pi", NULL},
743  {"huge", NULL},
744  {"maxinteger", NULL},
745  {"mininteger", NULL},
746  {NULL, NULL}
747};
748
749
750/*
751** Open math library
752*/
753LUAMOD_API int luaopen_math (lua_State *L) {
754  luaL_newlib(L, mathlib);
755  lua_pushnumber(L, PI);
756  lua_setfield(L, -2, "pi");
757  lua_pushnumber(L, (lua_Number)HUGE_VAL);
758  lua_setfield(L, -2, "huge");
759  lua_pushinteger(L, LUA_MAXINTEGER);
760  lua_setfield(L, -2, "maxinteger");
761  lua_pushinteger(L, LUA_MININTEGER);
762  lua_setfield(L, -2, "mininteger");
763  setrandfunc(L);
764  return 1;
765}
766
767