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