nanocoat/lib/3rdparty/lua/lmathlib.c

   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
  29 static 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
  40 static int math_sin (lua_State *L) {
  41   lua_pushnumber(L, l_mathop(sin)(luaL_checknumber(L, 1)));
  42   return 1;
  43 }
  44
  45 static int math_cos (lua_State *L) {
  46   lua_pushnumber(L, l_mathop(cos)(luaL_checknumber(L, 1)));
  47   return 1;
  48 }
  49
  50 static int math_tan (lua_State *L) {
  51   lua_pushnumber(L, l_mathop(tan)(luaL_checknumber(L, 1)));
  52   return 1;
  53 }
  54
  55 static int math_asin (lua_State *L) {
  56   lua_pushnumber(L, l_mathop(asin)(luaL_checknumber(L, 1)));
  57   return 1;
  58 }
  59
  60 static int math_acos (lua_State *L) {
  61   lua_pushnumber(L, l_mathop(acos)(luaL_checknumber(L, 1)));
  62   return 1;
  63 }
  64
  65 static 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
  73 static 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
  86 static 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
  95 static 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
 106 static 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
 117 static 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 */
 139 static 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
 156 static int math_sqrt (lua_State *L) {
 157   lua_pushnumber(L, l_mathop(sqrt)(luaL_checknumber(L, 1)));
 158   return 1;
 159 }
 160
 161
 162 static 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
 169 static 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
 190 static int math_exp (lua_State *L) {
 191   lua_pushnumber(L, l_mathop(exp)(luaL_checknumber(L, 1)));
 192   return 1;
 193 }
 194
 195 static int math_deg (lua_State *L) {
 196   lua_pushnumber(L, luaL_checknumber(L, 1) * (l_mathop(180.0) / PI));
 197   return 1;
 198 }
 199
 200 static 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
 206 static 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
 220 static 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
 234 static 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 */
 304 static Rand64 rotl (Rand64 x, int n) {
 305   return (x << n) | (trim64(x) >> (64 - n));
 306 }
 307
 308 static 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
 337 static 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
 352 typedef unsigned int lu_int32;
 353 #else
 354 typedef unsigned long lu_int32;
 355 #endif
 356
 357
 358 /*
 359 ** Use two 32-bit integers to represent a 64-bit quantity.
 360 */
 361 typedef 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 */
 382 static 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 */
 390 static 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 */
 396 static void Ixor (Rand64 *i1, Rand64 i2) {
 397   i1->h ^= i2.h;
 398   i1->l ^= i2.l;
 399 }
 400
 401 /* return i1 + i2 */
 402 static 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 */
 410 static Rand64 times5 (Rand64 i) {
 411   return Iadd(Ishl(i, 2), i);  /* i * 5 == (i << 2) + i */
 412 }
 413
 414 /* return i * 9 */
 415 static 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 */
 420 static 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 */
 427 static 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 */
 437 static 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 */
 467 static 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
 492 static 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' */
 502 static 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' */
 507 static 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 */
 517 typedef 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 */
 532 static 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
 557 static 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
 592 static 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 */
 611 static 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
 618 static 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
 632 static 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 */
 642 static 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
 659 static int math_cosh (lua_State *L) {
 660   lua_pushnumber(L, l_mathop(cosh)(luaL_checknumber(L, 1)));
 661   return 1;
 662 }
 663
 664 static int math_sinh (lua_State *L) {
 665   lua_pushnumber(L, l_mathop(sinh)(luaL_checknumber(L, 1)));
 666   return 1;
 667 }
 668
 669 static int math_tanh (lua_State *L) {
 670   lua_pushnumber(L, l_mathop(tanh)(luaL_checknumber(L, 1)));
 671   return 1;
 672 }
 673
 674 static 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
 681 static 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
 688 static 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
 695 static 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
 705 static 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 */
 751 LUAMOD_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