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/cvs/deliantra/server/include/util.h
Revision: 1.34
Committed: Fri Jan 19 15:15:50 2007 UTC (17 years, 5 months ago) by root
Content type: text/plain
Branch: MAIN
Changes since 1.33: +22 -4 lines
Log Message:
- goofing around with my skills (overoptimisation to learn something)

File Contents

# Content
1 #ifndef UTIL_H__
2 #define UTIL_H__
3
4 #if __GNUC__ >= 3
5 # define is_constant(c) __builtin_constant_p (c)
6 #else
7 # define is_constant(c) 0
8 #endif
9
10 #include <cstddef>
11 #include <cmath>
12 #include <new>
13 #include <vector>
14
15 #include <glib.h>
16
17 #include <shstr.h>
18 #include <traits.h>
19
20 // use a gcc extension for auto declarations until ISO C++ sanctifies them
21 #define AUTODECL(var,expr) typeof(expr) var = (expr)
22
23 // very ugly macro that basicaly declares and initialises a variable
24 // that is in scope for the next statement only
25 // works only for stuff that can be assigned 0 and converts to false
26 // (note: works great for pointers)
27 // most ugly macro I ever wrote
28 #define declvar(type, name, value) if (type name = 0) { } else if (((name) = (value)), 1)
29
30 // in range including end
31 #define IN_RANGE_INC(val,beg,end) \
32 ((unsigned int)(val) - (unsigned int)(beg) <= (unsigned int)(end) - (unsigned int)(beg))
33
34 // in range excluding end
35 #define IN_RANGE_EXC(val,beg,end) \
36 ((unsigned int)(val) - (unsigned int)(beg) < (unsigned int)(end) - (unsigned int)(beg))
37
38 void fork_abort (const char *msg);
39
40 template<typename T, typename U> static inline T min (T a, U b) { return a < (T)b ? a : (T)b; }
41 template<typename T, typename U> static inline T max (T a, U b) { return a > (T)b ? a : (T)b; }
42 template<typename T, typename U, typename V> static inline T clamp (T v, U a, V b) { return v < (T)a ? a : v >(T)b ? b : v; }
43
44 template<typename T, typename U> static inline void swap (T& a, U& b) { T t=a; a=(T)b; b=(U)t; }
45
46 // this is much faster than crossfires original algorithm
47 // on modern cpus
48 inline int
49 isqrt (int n)
50 {
51 return (int)sqrtf ((float)n);
52 }
53
54 // this is only twice as fast as naive sqrtf (dx*dy+dy*dy)
55 #if 0
56 // and has a max. error of 6 in the range -100..+100.
57 #else
58 // and has a max. error of 9 in the range -100..+100.
59 #endif
60 inline int
61 idistance (int dx, int dy)
62 {
63 unsigned int dx_ = abs (dx);
64 unsigned int dy_ = abs (dy);
65
66 #if 0
67 return dx_ > dy_
68 ? (dx_ * 61685 + dy_ * 26870) >> 16
69 : (dy_ * 61685 + dx_ * 26870) >> 16;
70 #else
71 return dx_ + dy_ - min (dx_, dy_) * 5 / 8;
72 #endif
73 }
74
75 /*
76 * absdir(int): Returns a number between 1 and 8, which represent
77 * the "absolute" direction of a number (it actually takes care of
78 * "overflow" in previous calculations of a direction).
79 */
80 inline int
81 absdir (int d)
82 {
83 return ((d - 1) & 7) + 1;
84 }
85
86 // makes dynamically allocated objects zero-initialised
87 struct zero_initialised
88 {
89 void *operator new (size_t s, void *p)
90 {
91 memset (p, 0, s);
92 return p;
93 }
94
95 void *operator new (size_t s)
96 {
97 return g_slice_alloc0 (s);
98 }
99
100 void *operator new[] (size_t s)
101 {
102 return g_slice_alloc0 (s);
103 }
104
105 void operator delete (void *p, size_t s)
106 {
107 g_slice_free1 (s, p);
108 }
109
110 void operator delete[] (void *p, size_t s)
111 {
112 g_slice_free1 (s, p);
113 }
114 };
115
116 void *salloc_ (int n) throw (std::bad_alloc);
117 void *salloc_ (int n, void *src) throw (std::bad_alloc);
118
119 // strictly the same as g_slice_alloc, but never returns 0
120 template<typename T>
121 inline T *salloc (int n = 1) throw (std::bad_alloc) { return (T *)salloc_ (n * sizeof (T)); }
122
123 // also copies src into the new area, like "memdup"
124 // if src is 0, clears the memory
125 template<typename T>
126 inline T *salloc (int n, T *src) throw (std::bad_alloc) { return (T *)salloc_ (n * sizeof (T), (void *)src); }
127
128 // clears the memory
129 template<typename T>
130 inline T *salloc0(int n = 1) throw (std::bad_alloc) { return (T *)salloc_ (n * sizeof (T), 0); }
131
132 // for symmetry
133 template<typename T>
134 inline void sfree (T *ptr, int n = 1) throw ()
135 {
136 g_slice_free1 (n * sizeof (T), (void *)ptr);
137 }
138
139 // a STL-compatible allocator that uses g_slice
140 // boy, this is verbose
141 template<typename Tp>
142 struct slice_allocator
143 {
144 typedef size_t size_type;
145 typedef ptrdiff_t difference_type;
146 typedef Tp *pointer;
147 typedef const Tp *const_pointer;
148 typedef Tp &reference;
149 typedef const Tp &const_reference;
150 typedef Tp value_type;
151
152 template <class U>
153 struct rebind
154 {
155 typedef slice_allocator<U> other;
156 };
157
158 slice_allocator () throw () { }
159 slice_allocator (const slice_allocator &o) throw () { }
160 template<typename Tp2>
161 slice_allocator (const slice_allocator<Tp2> &) throw () { }
162
163 ~slice_allocator () { }
164
165 pointer address (reference x) const { return &x; }
166 const_pointer address (const_reference x) const { return &x; }
167
168 pointer allocate (size_type n, const_pointer = 0)
169 {
170 return salloc<Tp> (n);
171 }
172
173 void deallocate (pointer p, size_type n)
174 {
175 sfree<Tp> (p, n);
176 }
177
178 size_type max_size ()const throw ()
179 {
180 return size_t (-1) / sizeof (Tp);
181 }
182
183 void construct (pointer p, const Tp &val)
184 {
185 ::new (p) Tp (val);
186 }
187
188 void destroy (pointer p)
189 {
190 p->~Tp ();
191 }
192 };
193
194 // P. L'Ecuyer, “Maximally Equidistributed Combined Tausworthe Generators”, Mathematics of Computation, 65, 213 (1996), 203–213.
195 // http://www.iro.umontreal.ca/~lecuyer/myftp/papers/tausme.ps
196 // http://www.iro.umontreal.ca/~lecuyer/myftp/papers/tausme2.ps
197 struct tausworthe_random_generator
198 {
199 // generator
200 uint32_t state [4];
201
202 void operator =(const tausworthe_random_generator &src)
203 {
204 state [0] = src.state [0];
205 state [1] = src.state [1];
206 state [2] = src.state [2];
207 state [3] = src.state [3];
208 }
209
210 void seed (uint32_t seed);
211 uint32_t next ();
212
213 // uniform distribution
214 uint32_t operator ()(uint32_t r_max)
215 {
216 return is_constant (r_max)
217 ? this->next () % r_max
218 : get_range (r_max);
219 }
220
221 // return a number within (min .. max)
222 int operator () (int r_min, int r_max)
223 {
224 return is_constant (r_min) && is_constant (r_max)
225 ? r_min + (*this) (max (r_max - r_min + 1, 1))
226 : get_range (r_min, r_max);
227 }
228
229 double operator ()()
230 {
231 return this->next () / (double)0xFFFFFFFFU;
232 }
233
234 protected:
235 uint32_t get_range (uint32_t r_max);
236 int get_range (int r_min, int r_max);
237 };
238
239 typedef tausworthe_random_generator rand_gen;
240
241 extern rand_gen rndm;
242
243 template<class T>
244 struct refptr
245 {
246 T *p;
247
248 refptr () : p(0) { }
249 refptr (const refptr<T> &p) : p(p.p) { if (p) p->refcnt_inc (); }
250 refptr (T *p) : p(p) { if (p) p->refcnt_inc (); }
251 ~refptr () { if (p) p->refcnt_dec (); }
252
253 const refptr<T> &operator =(T *o)
254 {
255 if (p) p->refcnt_dec ();
256 p = o;
257 if (p) p->refcnt_inc ();
258
259 return *this;
260 }
261
262 const refptr<T> &operator =(const refptr<T> o)
263 {
264 *this = o.p;
265 return *this;
266 }
267
268 T &operator * () const { return *p; }
269 T *operator ->() const { return p; }
270
271 operator T *() const { return p; }
272 };
273
274 typedef refptr<maptile> maptile_ptr;
275 typedef refptr<object> object_ptr;
276 typedef refptr<archetype> arch_ptr;
277 typedef refptr<client> client_ptr;
278 typedef refptr<player> player_ptr;
279
280 struct str_hash
281 {
282 std::size_t operator ()(const char *s) const
283 {
284 unsigned long hash = 0;
285
286 /* use the one-at-a-time hash function, which supposedly is
287 * better than the djb2-like one used by perl5.005, but
288 * certainly is better then the bug used here before.
289 * see http://burtleburtle.net/bob/hash/doobs.html
290 */
291 while (*s)
292 {
293 hash += *s++;
294 hash += hash << 10;
295 hash ^= hash >> 6;
296 }
297
298 hash += hash << 3;
299 hash ^= hash >> 11;
300 hash += hash << 15;
301
302 return hash;
303 }
304 };
305
306 struct str_equal
307 {
308 bool operator ()(const char *a, const char *b) const
309 {
310 return !strcmp (a, b);
311 }
312 };
313
314 template<class T>
315 struct unordered_vector : std::vector<T, slice_allocator<T> >
316 {
317 typedef typename unordered_vector::iterator iterator;
318
319 void erase (unsigned int pos)
320 {
321 if (pos < this->size () - 1)
322 (*this)[pos] = (*this)[this->size () - 1];
323
324 this->pop_back ();
325 }
326
327 void erase (iterator i)
328 {
329 erase ((unsigned int )(i - this->begin ()));
330 }
331 };
332
333 template<class T, int T::* index>
334 struct object_vector : std::vector<T *, slice_allocator<T *> >
335 {
336 void insert (T *obj)
337 {
338 assert (!(obj->*index));
339 push_back (obj);
340 obj->*index = this->size ();
341 }
342
343 void insert (T &obj)
344 {
345 insert (&obj);
346 }
347
348 void erase (T *obj)
349 {
350 assert (obj->*index);
351 int pos = obj->*index;
352 obj->*index = 0;
353
354 if (pos < this->size ())
355 {
356 (*this)[pos - 1] = (*this)[this->size () - 1];
357 (*this)[pos - 1]->*index = pos;
358 }
359
360 this->pop_back ();
361 }
362
363 void erase (T &obj)
364 {
365 errase (&obj);
366 }
367 };
368
369 // basically does what strncpy should do, but appends "..." to strings exceeding length
370 void assign (char *dst, const char *src, int maxlen);
371
372 // type-safe version of assign
373 template<int N>
374 inline void assign (char (&dst)[N], const char *src)
375 {
376 assign ((char *)&dst, src, N);
377 }
378
379 typedef double tstamp;
380
381 // return current time as timestampe
382 tstamp now ();
383
384 int similar_direction (int a, int b);
385
386 #endif
387