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Comparing deliantra/server/include/util.h (file contents):
Revision 1.108 by root, Wed May 26 19:11:43 2010 UTC vs.
Revision 1.113 by root, Fri Apr 22 02:03:11 2011 UTC

… …
114 114
115// sign0 returns -1, 0 or +1 115// sign0 returns -1, 0 or +1
116template<typename T> 116template<typename T>
117static inline T sign0 (T v) { return v ? sign (v) : 0; } 117static inline T sign0 (T v) { return v ? sign (v) : 0; }
118 118
119//clashes with C++0x
119template<typename T, typename U> 120template<typename T, typename U>
120static inline T copysign (T a, U b) { return a > 0 ? b : -b; } 121static inline T copysign (T a, U b) { return a > 0 ? b : -b; }
121 122
122// div* only work correctly for div > 0 123// div* only work correctly for div > 0
123// div, with correct rounding (< 0.5 downwards, >=0.5 upwards) 124// div, with correct rounding (< 0.5 downwards, >=0.5 upwards)
… …
429 { 430 {
430 p->~Tp (); 431 p->~Tp ();
431 } 432 }
432}; 433};
433 434
434// P. L'Ecuyer, “Maximally Equidistributed Combined Tausworthe Generators”, Mathematics of Computation, 65, 213 (1996), 203–213.
435// http://www.iro.umontreal.ca/~lecuyer/myftp/papers/tausme.ps
436// http://www.iro.umontreal.ca/~lecuyer/myftp/papers/tausme2.ps
437struct tausworthe_random_generator
438{
439 uint32_t state [4];
440
441 void operator =(const tausworthe_random_generator &src)
442 {
443 state [0] = src.state [0];
444 state [1] = src.state [1];
445 state [2] = src.state [2];
446 state [3] = src.state [3];
447 }
448
449 void seed (uint32_t seed);
450 uint32_t next ();
451};
452
453// Xorshift RNGs, George Marsaglia
454// http://www.jstatsoft.org/v08/i14/paper
455// this one is about 40% faster than the tausworthe one above (i.e. not much),
456// despite the inlining, and has the issue of only creating 2**32-1 numbers.
457// see also http://www.iro.umontreal.ca/~lecuyer/myftp/papers/xorshift.pdf
458struct xorshift_random_generator
459{
460 uint32_t x, y;
461
462 void operator =(const xorshift_random_generator &src)
463 {
464 x = src.x;
465 y = src.y;
466 }
467
468 void seed (uint32_t seed)
469 {
470 x = seed;
471 y = seed * 69069U;
472 }
473
474 uint32_t next ()
475 {
476 uint32_t t = x ^ (x << 10);
477 x = y;
478 y = y ^ (y >> 13) ^ t ^ (t >> 10);
479 return y;
480 }
481};
482
483template<class generator>
484struct random_number_generator : generator
485{
486 // uniform distribution, [0 .. num - 1]
487 uint32_t operator ()(uint32_t num)
488 {
489 return !is_constant (num) ? get_range (num) // non-constant
490 : num & (num - 1) ? (this->next () * (uint64_t)num) >> 32U // constant, non-power-of-two
491 : this->next () & (num - 1); // constant, power-of-two
492 }
493
494 // return a number within the closed interval [min .. max]
495 int operator () (int r_min, int r_max)
496 {
497 return is_constant (r_min <= r_max) && r_min <= r_max
498 ? r_min + operator ()(r_max - r_min + 1)
499 : get_range (r_min, r_max);
500 }
501
502 // return a number within the half-open interval [0..1[
503 double operator ()()
504 {
505 return this->next () / (double)0x100000000ULL;
506 }
507
508protected:
509 uint32_t get_range (uint32_t r_max);
510 int get_range (int r_min, int r_max);
511};
512
513typedef random_number_generator<tausworthe_random_generator> rand_gen;
514
515extern rand_gen rndm, rmg_rndm;
516
517INTERFACE_CLASS (attachable) 435INTERFACE_CLASS (attachable)
518struct refcnt_base 436struct refcnt_base
519{ 437{
520 typedef int refcnt_t; 438 typedef int refcnt_t;
521 mutable refcnt_t ACC (RW, refcnt); 439 mutable refcnt_t ACC (RW, refcnt);
… …
594 // use FNV-1a hash (http://isthe.com/chongo/tech/comp/fnv/) 512 // use FNV-1a hash (http://isthe.com/chongo/tech/comp/fnv/)
595 // it is about twice as fast as the one-at-a-time one, 513 // it is about twice as fast as the one-at-a-time one,
596 // with good distribution. 514 // with good distribution.
597 // FNV-1a is faster on many cpus because the multiplication 515 // FNV-1a is faster on many cpus because the multiplication
598 // runs concurrently with the looping logic. 516 // runs concurrently with the looping logic.
517 // we modify the hash a bit to improve its distribution
599 uint32_t hash = STRHSH_NULL; 518 uint32_t hash = STRHSH_NULL;
600 519
601 while (*s) 520 while (*s)
602 hash = (hash ^ *s++) * 16777619U; 521 hash = (hash ^ *s++) * 16777619U;
603 522
604 return hash; 523 return hash ^ (hash >> 16);
605} 524}
606 525
607static inline uint32_t 526static inline uint32_t
608memhsh (const char *s, size_t len) 527memhsh (const char *s, size_t len)
609{ 528{
… …
724 { 643 {
725 erase (&obj); 644 erase (&obj);
726 } 645 }
727}; 646};
728 647
648/////////////////////////////////////////////////////////////////////////////
649
650// something like a vector or stack, but without
651// out of bounds checking
652template<typename T>
653struct fixed_stack
654{
655 T *data;
656 int size;
657 int max;
658
659 fixed_stack ()
660 : size (0), data (0)
661 {
662 }
663
664 fixed_stack (int max)
665 : size (0), max (max)
666 {
667 data = salloc<T> (max);
668 }
669
670 void reset (int new_max)
671 {
672 sfree (data, max);
673 size = 0;
674 max = new_max;
675 data = salloc<T> (max);
676 }
677
678 void free ()
679 {
680 sfree (data, max);
681 data = 0;
682 }
683
684 ~fixed_stack ()
685 {
686 sfree (data, max);
687 }
688
689 T &operator[](int idx)
690 {
691 return data [idx];
692 }
693
694 void push (T v)
695 {
696 data [size++] = v;
697 }
698
699 T &pop ()
700 {
701 return data [--size];
702 }
703
704 T remove (int idx)
705 {
706 T v = data [idx];
707
708 data [idx] = data [--size];
709
710 return v;
711 }
712};
713
714/////////////////////////////////////////////////////////////////////////////
715
729// basically does what strncpy should do, but appends "..." to strings exceeding length 716// basically does what strncpy should do, but appends "..." to strings exceeding length
730// returns the number of bytes actually used (including \0) 717// returns the number of bytes actually used (including \0)
731int assign (char *dst, const char *src, int maxsize); 718int assign (char *dst, const char *src, int maxsize);
732 719
733// type-safe version of assign 720// type-safe version of assign

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