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Comparing deliantra/server/include/util.h (file contents):
Revision 1.78 by root, Thu Dec 4 03:48:19 2008 UTC vs.
Revision 1.85 by root, Thu Jan 1 20:49:48 2009 UTC

… …
28 28
29#if __GNUC__ >= 3 29#if __GNUC__ >= 3
30# define is_constant(c) __builtin_constant_p (c) 30# define is_constant(c) __builtin_constant_p (c)
31# define expect(expr,value) __builtin_expect ((expr),(value)) 31# define expect(expr,value) __builtin_expect ((expr),(value))
32# define prefetch(addr,rw,locality) __builtin_prefetch (addr, rw, locality) 32# define prefetch(addr,rw,locality) __builtin_prefetch (addr, rw, locality)
33# define noinline __attribute__((__noinline__))
33#else 34#else
34# define is_constant(c) 0 35# define is_constant(c) 0
35# define expect(expr,value) (expr) 36# define expect(expr,value) (expr)
36# define prefetch(addr,rw,locality) 37# define prefetch(addr,rw,locality)
38# define noinline
37#endif 39#endif
38 40
39#if __GNUC__ < 4 || (__GNUC__ == 4 || __GNUC_MINOR__ < 4) 41#if __GNUC__ < 4 || (__GNUC__ == 4 || __GNUC_MINOR__ < 4)
40# define decltype(x) typeof(x) 42# define decltype(x) typeof(x)
41#endif 43#endif
42 44
43// put into ifs if you are very sure that the expression 45// put into ifs if you are very sure that the expression
44// is mostly true or mosty false. note that these return 46// is mostly true or mosty false. note that these return
45// booleans, not the expression. 47// booleans, not the expression.
46#define expect_false(expr) expect ((expr) != 0, 0) 48#define expect_false(expr) expect ((expr) ? 1 : 0, 0)
47#define expect_true(expr) expect ((expr) != 0, 1) 49#define expect_true(expr) expect ((expr) ? 1 : 0, 1)
48 50
49#include <pthread.h> 51#include <pthread.h>
50 52
51#include <cstddef> 53#include <cstddef>
52#include <cmath> 54#include <cmath>
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72#endif 74#endif
73 75
74// use C0X decltype for auto declarations until ISO C++ sanctifies them (if ever) 76// use C0X decltype for auto declarations until ISO C++ sanctifies them (if ever)
75#define auto(var,expr) decltype(expr) var = (expr) 77#define auto(var,expr) decltype(expr) var = (expr)
76 78
77// very ugly macro that basicaly declares and initialises a variable 79// very ugly macro that basically declares and initialises a variable
78// that is in scope for the next statement only 80// that is in scope for the next statement only
79// works only for stuff that can be assigned 0 and converts to false 81// works only for stuff that can be assigned 0 and converts to false
80// (note: works great for pointers) 82// (note: works great for pointers)
81// most ugly macro I ever wrote 83// most ugly macro I ever wrote
82#define statementvar(type, name, value) if (type name = 0) { } else if (((name) = (value)), 1) 84#define statementvar(type, name, value) if (type name = 0) { } else if (((name) = (value)), 1)
… …
96// as a is often a constant while b is the variable. it is still a bug, though. 98// as a is often a constant while b is the variable. it is still a bug, though.
97template<typename T, typename U> static inline T min (T a, U b) { return (U)a < b ? (U)a : b; } 99template<typename T, typename U> static inline T min (T a, U b) { return (U)a < b ? (U)a : b; }
98template<typename T, typename U> static inline T max (T a, U b) { return (U)a > b ? (U)a : b; } 100template<typename T, typename U> static inline T max (T a, U b) { return (U)a > b ? (U)a : b; }
99template<typename T, typename U, typename V> static inline T clamp (T v, U a, V b) { return v < (T)a ? (T)a : v >(T)b ? (T)b : v; } 101template<typename T, typename U, typename V> static inline T clamp (T v, U a, V b) { return v < (T)a ? (T)a : v >(T)b ? (T)b : v; }
100 102
101template<typename T> static inline void min_it (T &v, T m) { v = min (v, m); } 103template<typename T, typename U> static inline void min_it (T &v, U m) { v = min (v, (T)m); }
102template<typename T> static inline void max_it (T &v, T m) { v = max (v, m); } 104template<typename T, typename U> static inline void max_it (T &v, U m) { v = max (v, (T)m); }
103template<typename T> static inline void clamp_it (T &v, T a, T b) { v = clamp (v, a, b); } 105template<typename T, typename U, typename V> static inline void clamp_it (T &v, U a, V b) { v = clamp (v, (T)a, (T)b); }
104 106
105template<typename T, typename U> static inline void swap (T& a, U& b) { T t=a; a=(T)b; b=(U)t; } 107template<typename T, typename U> static inline void swap (T& a, U& b) { T t=a; a=(T)b; b=(U)t; }
106 108
107template<typename T, typename U, typename V> static inline T min (T a, U b, V c) { return min (a, min (b, c)); } 109template<typename T, typename U, typename V> static inline T min (T a, U b, V c) { return min (a, min (b, c)); }
108template<typename T, typename U, typename V> static inline T max (T a, U b, V c) { return max (a, max (b, c)); } 110template<typename T, typename U, typename V> static inline T max (T a, U b, V c) { return max (a, max (b, c)); }
111
112// sign returns -1 or +1
113template<typename T>
114static inline T sign (T v) { return v < 0 ? -1 : +1; }
115// relies on 2c representation
116template<>
117inline sint8 sign (sint8 v) { return 1 - (sint8 (uint8 (v) >> 7) * 2); }
118
119// sign0 returns -1, 0 or +1
120template<typename T>
121static inline T sign0 (T v) { return v ? sign (v) : 0; }
109 122
110// div, with correct rounding (< 0.5 downwards, >=0.5 upwards) 123// div, with correct rounding (< 0.5 downwards, >=0.5 upwards)
111template<typename T> static inline T div (T val, T div) { return (val + div / 2) / div; } 124template<typename T> static inline T div (T val, T div) { return (val + div / 2) / div; }
112// div, round-up 125// div, round-up
113template<typename T> static inline T div_ru (T val, T div) { return (val + div - 1) / div; } 126template<typename T> static inline T div_ru (T val, T div) { return (val + div - 1) / div; }
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378// P. L'Ecuyer, “Maximally Equidistributed Combined Tausworthe Generators”, Mathematics of Computation, 65, 213 (1996), 203–213. 391// P. L'Ecuyer, “Maximally Equidistributed Combined Tausworthe Generators”, Mathematics of Computation, 65, 213 (1996), 203–213.
379// http://www.iro.umontreal.ca/~lecuyer/myftp/papers/tausme.ps 392// http://www.iro.umontreal.ca/~lecuyer/myftp/papers/tausme.ps
380// http://www.iro.umontreal.ca/~lecuyer/myftp/papers/tausme2.ps 393// http://www.iro.umontreal.ca/~lecuyer/myftp/papers/tausme2.ps
381struct tausworthe_random_generator 394struct tausworthe_random_generator
382{ 395{
383 // generator
384 uint32_t state [4]; 396 uint32_t state [4];
385 397
386 void operator =(const tausworthe_random_generator &src) 398 void operator =(const tausworthe_random_generator &src)
387 { 399 {
388 state [0] = src.state [0]; 400 state [0] = src.state [0];
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391 state [3] = src.state [3]; 403 state [3] = src.state [3];
392 } 404 }
393 405
394 void seed (uint32_t seed); 406 void seed (uint32_t seed);
395 uint32_t next (); 407 uint32_t next ();
408};
396 409
410// Xorshift RNGs, George Marsaglia
411// http://www.jstatsoft.org/v08/i14/paper
412// this one is about 40% faster than the tausworthe one above (i.e. not much),
413// despite the inlining, and has the issue of only creating 2**32-1 numbers.
414struct xorshift_random_generator
415{
416 uint32_t x, y;
417
418 void operator =(const xorshift_random_generator &src)
419 {
420 x = src.x;
421 y = src.y;
422 }
423
424 void seed (uint32_t seed)
425 {
426 x = seed;
427 y = seed * 69069U;
428 }
429
430 uint32_t next ()
431 {
432 uint32_t t = x ^ (x << 10);
433 x = y;
434 y = y ^ (y >> 13) ^ t ^ (t >> 10);
435 return y;
436 }
437};
438
439template<class generator>
440struct random_number_generator : generator
441{
397 // uniform distribution, 0 .. max (0, num - 1) 442 // uniform distribution, 0 .. max (0, num - 1)
398 uint32_t operator ()(uint32_t num) 443 uint32_t operator ()(uint32_t num)
399 { 444 {
400 return is_constant (num) 445 return !is_constant (num) ? get_range (num) // non-constant
401 ? (next () * (uint64_t)num) >> 32U 446 : num & (num - 1) ? (this->next () * (uint64_t)num) >> 32U // constant, non-power-of-two
402 : get_range (num); 447 : this->next () & (num - 1); // constant, power-of-two
403 } 448 }
404 449
405 // return a number within (min .. max) 450 // return a number within (min .. max)
406 int operator () (int r_min, int r_max) 451 int operator () (int r_min, int r_max)
407 { 452 {
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418protected: 463protected:
419 uint32_t get_range (uint32_t r_max); 464 uint32_t get_range (uint32_t r_max);
420 int get_range (int r_min, int r_max); 465 int get_range (int r_min, int r_max);
421}; 466};
422 467
423typedef tausworthe_random_generator rand_gen; 468typedef random_number_generator<tausworthe_random_generator> rand_gen;
424 469
425extern rand_gen rndm, rmg_rndm; 470extern rand_gen rndm, rmg_rndm;
426 471
427INTERFACE_CLASS (attachable) 472INTERFACE_CLASS (attachable)
428struct refcnt_base 473struct refcnt_base
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497 542
498struct str_hash 543struct str_hash
499{ 544{
500 std::size_t operator ()(const char *s) const 545 std::size_t operator ()(const char *s) const
501 { 546 {
502 unsigned long hash = 0; 547#if 0
548 uint32_t hash = 0;
503 549
504 /* use the one-at-a-time hash function, which supposedly is 550 /* use the one-at-a-time hash function, which supposedly is
505 * better than the djb2-like one used by perl5.005, but 551 * better than the djb2-like one used by perl5.005, but
506 * certainly is better then the bug used here before. 552 * certainly is better then the bug used here before.
507 * see http://burtleburtle.net/bob/hash/doobs.html 553 * see http://burtleburtle.net/bob/hash/doobs.html
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514 } 560 }
515 561
516 hash += hash << 3; 562 hash += hash << 3;
517 hash ^= hash >> 11; 563 hash ^= hash >> 11;
518 hash += hash << 15; 564 hash += hash << 15;
565#else
566 // use FNV-1a hash (http://isthe.com/chongo/tech/comp/fnv/)
567 // it is about twice as fast as the one-at-a-time one,
568 // with good distribution.
569 // FNV-1a is faster on many cpus because the multiplication
570 // runs concurrent with the looping logic.
571 uint32_t hash = 2166136261;
572
573 while (*s)
574 hash = (hash ^ *s++) * 16777619;
575#endif
519 576
520 return hash; 577 return hash;
521 } 578 }
522}; 579};
523 580

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