server/include/util.h

/*
 * This file is part of Deliantra, the Roguelike Realtime MMORPG.
 * 
 * Copyright (©) 2005,2006,2007 Marc Alexander Lehmann / Robin Redeker / the Deliantra team
 * 
 * Deliantra is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 * 
 * The authors can be reached via e-mail to <support@deliantra.net>
 */

#ifndef UTIL_H__
#define UTIL_H__

//#define PREFER_MALLOC

#if __GNUC__ >= 3
# define is_constant(c)             __builtin_constant_p (c)
# define expect(expr,value)         __builtin_expect ((expr),(value))
# define prefetch(addr,rw,locality) __builtin_prefetch (addr, rw, locality)
#else
# define is_constant(c)             0
# define expect(expr,value)         (expr)
# define prefetch(addr,rw,locality)
#endif

#if __GNUC__ < 4 || (__GNUC__ == 4 || __GNUC_MINOR__ < 4)
# define decltype(x) typeof(x)
#endif

// put into ifs if you are very sure that the expression
// is mostly true or mosty false. note that these return
// booleans, not the expression.
#define expect_false(expr) expect ((expr) != 0, 0)
#define expect_true(expr)  expect ((expr) != 0, 1)

#include <cstddef>
#include <cmath>
#include <new>
#include <vector>

#include <glib.h>

#include <shstr.h>
#include <traits.h>

// use C0X decltype for auto declarations until ISO C++ sanctifies them (if ever)
#define auto(var,expr) decltype(expr) var = (expr)

// very ugly macro that basicaly declares and initialises a variable
// that is in scope for the next statement only
// works only for stuff that can be assigned 0 and converts to false
// (note: works great for pointers)
// most ugly macro I ever wrote
#define statementvar(type, name, value) if (type name = 0) { } else if (((name) = (value)), 1)

// in range including end
#define IN_RANGE_INC(val,beg,end) \
  ((unsigned int)(val) - (unsigned int)(beg) <= (unsigned int)(end) - (unsigned int)(beg))

// in range excluding end
#define IN_RANGE_EXC(val,beg,end) \
  ((unsigned int)(val) - (unsigned int)(beg) <  (unsigned int)(end) - (unsigned int)(beg))

void fork_abort (const char *msg);

// rationale for using (U) not (T) is to reduce signed/unsigned issues,
// as a is often a constant while b is the variable. it is still a bug, though.
template<typename T, typename U> static inline T min (T a, U b) { return (U)a < b ? (U)a : b; }
template<typename T, typename U> static inline T max (T a, U b) { return (U)a > b ? (U)a : b; }
template<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; }

template<typename T, typename U> static inline void swap (T& a, U& b) { T t=a; a=(T)b; b=(U)t; }

template<typename T>
static inline T
lerp (T val, T min_in, T max_in, T min_out, T max_out)
{
  return (val - min_in) * (max_out - min_out) / (max_in - min_in) + min_out;
}

// lots of stuff taken from FXT

/* Rotate right. This is used in various places for checksumming */
//TODO: that sucks, use a better checksum algo
static inline uint32_t
rotate_right (uint32_t c, uint32_t count = 1)
{
  return (c << (32 - count)) | (c >> count);
}

static inline uint32_t
rotate_left (uint32_t c, uint32_t count = 1)
{
  return (c >> (32 - count)) | (c << count);
}

// Return abs(a-b)
// Both a and b must not have the most significant bit set
static inline uint32_t
upos_abs_diff (uint32_t a, uint32_t b)
{
  long d1 = b - a;
  long d2 = (d1 & (d1 >> 31)) << 1;

  return d1 - d2;               // == (b - d) - (a + d);
}

// Both a and b must not have the most significant bit set
static inline uint32_t
upos_min (uint32_t a, uint32_t b)
{
  int32_t d = b - a;
  d &= d >> 31;
  return a + d;
}

// Both a and b must not have the most significant bit set
static inline uint32_t
upos_max (uint32_t a, uint32_t b)
{
  int32_t d = b - a;
  d &= d >> 31;
  return b - d;
}

// this is much faster than crossfires original algorithm
// on modern cpus
inline int
isqrt (int n)
{
  return (int)sqrtf ((float)n);
}

// this is only twice as fast as naive sqrtf (dx*dy+dy*dy)
#if 0
// and has a max. error of 6 in the range -100..+100.
#else
// and has a max. error of 9 in the range -100..+100.
#endif
inline int 
idistance (int dx, int dy)
{ 
  unsigned int dx_ = abs (dx);
  unsigned int dy_ = abs (dy);

#if 0
  return dx_ > dy_
      ? (dx_ * 61685 + dy_ * 26870) >> 16
      : (dy_ * 61685 + dx_ * 26870) >> 16;
#else
  return dx_ + dy_ - min (dx_, dy_) * 5 / 8;
#endif
}

/*
 * absdir(int): Returns a number between 1 and 8, which represent
 * the "absolute" direction of a number (it actually takes care of
 * "overflow" in previous calculations of a direction).
 */
inline int
absdir (int d)
{
  return ((d - 1) & 7) + 1;
}

extern size_t slice_alloc; // statistics

// makes dynamically allocated objects zero-initialised
struct zero_initialised
{
  void *operator new (size_t s, void *p)
  {
    memset (p, 0, s);
    return p;
  }

  void *operator new (size_t s)
  {
    slice_alloc += s;
    return g_slice_alloc0 (s);
  }

  void *operator new[] (size_t s)
  {
    slice_alloc += s;
    return g_slice_alloc0 (s);
  }

  void operator delete (void *p, size_t s)
  {
    slice_alloc -= s;
    g_slice_free1 (s, p);
  }

  void operator delete[] (void *p, size_t s)
  {
    slice_alloc -= s;
    g_slice_free1 (s, p);
  }
};

void *salloc_ (int n)            throw (std::bad_alloc);
void *salloc_ (int n, void *src) throw (std::bad_alloc);

// strictly the same as g_slice_alloc, but never returns 0
template<typename T>
inline T *salloc (int n = 1)     throw (std::bad_alloc) { return (T *)salloc_ (n * sizeof (T));              }

// also copies src into the new area, like "memdup"
// if src is 0, clears the memory
template<typename T>
inline T *salloc (int n, T *src) throw (std::bad_alloc) { return (T *)salloc_ (n * sizeof (T), (void *)src); }

// clears the memory
template<typename T>
inline T *salloc0(int n = 1)     throw (std::bad_alloc) { return (T *)salloc_ (n * sizeof (T), 0);           }

// for symmetry
template<typename T>
inline void sfree (T *ptr, int n = 1) throw ()
{
#ifdef PREFER_MALLOC
  free (ptr);
#else
  slice_alloc -= n * sizeof (T);
  g_slice_free1 (n * sizeof (T), (void *)ptr);
#endif
}

// a STL-compatible allocator that uses g_slice
// boy, this is verbose
template<typename Tp>
struct slice_allocator
{
  typedef size_t size_type;
  typedef ptrdiff_t difference_type;
  typedef Tp *pointer;
  typedef const Tp *const_pointer;
  typedef Tp &reference;
  typedef const Tp &const_reference;
  typedef Tp value_type;

  template <class U> 
  struct rebind
  {
    typedef slice_allocator<U> other;
  };

  slice_allocator () throw () { }
  slice_allocator (const slice_allocator &o) throw () { }
  template<typename Tp2>
  slice_allocator (const slice_allocator<Tp2> &) throw () { }

  ~slice_allocator () { }

  pointer address (reference x) const { return &x; }
  const_pointer address (const_reference x) const { return &x; }

  pointer allocate (size_type n, const_pointer = 0)
  {
    return salloc<Tp> (n);
  }

  void deallocate (pointer p, size_type n)
  {
    sfree<Tp> (p, n);
  }

  size_type max_size ()const throw ()
  {
    return size_t (-1) / sizeof (Tp);
  }

  void construct (pointer p, const Tp &val)
  {
    ::new (p) Tp (val);
  }

  void destroy (pointer p)
  {
    p->~Tp ();
  }
};

// P. L'Ecuyer, “Maximally Equidistributed Combined Tausworthe Generators”, Mathematics of Computation, 65, 213 (1996), 203–213.
// http://www.iro.umontreal.ca/~lecuyer/myftp/papers/tausme.ps
// http://www.iro.umontreal.ca/~lecuyer/myftp/papers/tausme2.ps
struct tausworthe_random_generator
{
  // generator
  uint32_t state [4];

  void operator =(const tausworthe_random_generator &src)
  {
    state [0] = src.state [0];
    state [1] = src.state [1];
    state [2] = src.state [2];
    state [3] = src.state [3];
  }

  void seed (uint32_t seed);
  uint32_t next ();

  // uniform distribution
  uint32_t operator ()(uint32_t num)
  {
    return is_constant (num)
             ? (next () * (uint64_t)num) >> 32U
             : get_range (num);
  }

  // return a number within (min .. max)
  int operator () (int r_min, int r_max)
  {
    return is_constant (r_min) && is_constant (r_max) && r_min <= r_max
              ? r_min + operator ()(r_max - r_min + 1)
              : get_range (r_min, r_max);
  }

  double operator ()()
  {
    return this->next () / (double)0xFFFFFFFFU;
  }

protected:
  uint32_t get_range (uint32_t r_max);
  int get_range (int r_min, int r_max);
};

typedef tausworthe_random_generator rand_gen;

extern rand_gen rndm;

INTERFACE_CLASS (attachable)
struct refcnt_base
{
  typedef int refcnt_t;
  mutable refcnt_t ACC (RW, refcnt);

  MTH void refcnt_inc () const { ++refcnt; }
  MTH void refcnt_dec () const { --refcnt; }

  refcnt_base () : refcnt (0) { }
};

// to avoid branches with more advanced compilers
extern refcnt_base::refcnt_t refcnt_dummy;

template<class T>
struct refptr
{
  // p if not null
  refcnt_base::refcnt_t *refcnt_ref () { return p ? &p->refcnt : &refcnt_dummy; }

  void refcnt_dec ()
  {
    if (!is_constant (p))
      --*refcnt_ref ();
    else if (p)
      --p->refcnt;
  }

  void refcnt_inc ()
  {
    if (!is_constant (p))
      ++*refcnt_ref ();
    else if (p)
      ++p->refcnt;
  }

  T *p;

  refptr () : p(0) { }
  refptr (const refptr<T> &p) : p(p.p) { refcnt_inc (); }
  refptr (T *p) : p(p) { refcnt_inc (); }
  ~refptr () { refcnt_dec (); }

  const refptr<T> &operator =(T *o)
  {
    // if decrementing ever destroys we need to reverse the order here
    refcnt_dec ();
    p = o;
    refcnt_inc ();
    return *this;
  }

  const refptr<T> &operator =(const refptr<T> &o)
  {
    *this = o.p;
    return *this;
  }

  T &operator * () const { return *p; }
  T *operator ->() const { return  p; }

  operator T *() const { return p; }
};

typedef refptr<maptile>   maptile_ptr;
typedef refptr<object>    object_ptr;
typedef refptr<archetype> arch_ptr;
typedef refptr<client>    client_ptr;
typedef refptr<player>    player_ptr;

struct str_hash
{
  std::size_t operator ()(const char *s) const
  {
    unsigned long hash = 0;

    /* use the one-at-a-time hash function, which supposedly is
     * better than the djb2-like one used by perl5.005, but
     * certainly is better then the bug used here before.
     * see http://burtleburtle.net/bob/hash/doobs.html
     */
    while (*s)
      {
        hash += *s++;
        hash += hash << 10;
        hash ^= hash >>  6;
      }

    hash += hash <<  3;
    hash ^= hash >> 11;
    hash += hash << 15;

    return hash;
  }
};

struct str_equal
{
  bool operator ()(const char *a, const char *b) const
  {
    return !strcmp (a, b);
  }
};

// Mostly the same as std::vector, but insert/erase can reorder
// the elements, making append(=insert)/remove O(1) instead of O(n).
//
// NOTE: only some forms of erase are available
template<class T>
struct unordered_vector : std::vector<T, slice_allocator<T> >
{
  typedef typename unordered_vector::iterator iterator;

  void erase (unsigned int pos)
  {
    if (pos < this->size () - 1)
      (*this)[pos] = (*this)[this->size () - 1];

    this->pop_back ();
  }

  void erase (iterator i)
  {
    erase ((unsigned int )(i - this->begin ()));
  }
};

// This container blends advantages of linked lists
// (efficiency) with vectors (random access) by
// by using an unordered vector and storing the vector
// index inside the object.
//
// + memory-efficient on most 64 bit archs
// + O(1) insert/remove
// + free unique (but varying) id for inserted objects
// + cache-friendly iteration
// - only works for pointers to structs
//
// NOTE: only some forms of erase/insert are available
typedef int object_vector_index;

template<class T, object_vector_index T::*indexmember>
struct object_vector : std::vector<T *, slice_allocator<T *> >
{
  typedef typename object_vector::iterator iterator;

  bool contains (const T *obj) const
  {
    return obj->*indexmember;
  }

  iterator find (const T *obj)
  {
    return obj->*indexmember
      ? this->begin () + obj->*indexmember - 1
      : this->end ();
  }

  void push_back (T *obj)
  {
    std::vector<T *, slice_allocator<T *> >::push_back (obj);
    obj->*indexmember = this->size ();
  }

  void insert (T *obj)
  {
    push_back (obj);
  }

  void insert (T &obj)
  {
    insert (&obj);
  }

  void erase (T *obj)
  {
    unsigned int pos = obj->*indexmember;
    obj->*indexmember = 0;

    if (pos < this->size ())
      {
        (*this)[pos - 1] = (*this)[this->size () - 1];
        (*this)[pos - 1]->*indexmember = pos;
      }

    this->pop_back ();
  }

  void erase (T &obj)
  {
    erase (&obj);
  }
};

// basically does what strncpy should do, but appends "..." to strings exceeding length
void assign (char *dst, const char *src, int maxlen);

// type-safe version of assign
template<int N>
inline void assign (char (&dst)[N], const char *src)
{
  assign ((char *)&dst, src, N);
}

typedef double tstamp;

// return current time as timestamp
tstamp now ();

int similar_direction (int a, int b);

// like sprintf, but returns a "static" buffer
const char *format (const char *format, ...);

#endif

Revision:	1.59
Committed:	Sun Dec 16 02:50:33 2007 UTC (16 years, 5 months ago) by root
Content type:	text/plain
Branch:	MAIN
CVS Tags:	rel-2_4
Changes since 1.58:	+1 -1 lines
Log Message:	* empty log message *
#	Content
1	/*
2	* This file is part of Deliantra, the Roguelike Realtime MMORPG.
3	*
4	* Copyright (©) 2005,2006,2007 Marc Alexander Lehmann / Robin Redeker / the Deliantra team
5	*
6	* Deliantra is free software: you can redistribute it and/or modify
7	* it under the terms of the GNU General Public License as published by
8	* the Free Software Foundation, either version 3 of the License, or
9	* (at your option) any later version.
10	*
11	* This program is distributed in the hope that it will be useful,
12	* but WITHOUT ANY WARRANTY; without even the implied warranty of
13	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14	* GNU General Public License for more details.
15	*
16	* You should have received a copy of the GNU General Public License
17	* along with this program. If not, see <http://www.gnu.org/licenses/>.
18	*
19	* The authors can be reached via e-mail to <support@deliantra.net>
20	*/
21
22	#ifndef UTIL_H__
23	#define UTIL_H__
24
25	//#define PREFER_MALLOC
26
27	#if __GNUC__ >= 3
28	# define is_constant(c) __builtin_constant_p (c)
29	# define expect(expr,value) __builtin_expect ((expr),(value))
30	# define prefetch(addr,rw,locality) __builtin_prefetch (addr, rw, locality)
31	#else
32	# define is_constant(c) 0
33	# define expect(expr,value) (expr)
34	# define prefetch(addr,rw,locality)
35	#endif
36
37	#if __GNUC__ < 4 \|\| (__GNUC__ == 4 \|\| __GNUC_MINOR__ < 4)
38	# define decltype(x) typeof(x)
39	#endif
40
41	// put into ifs if you are very sure that the expression
42	// is mostly true or mosty false. note that these return
43	// booleans, not the expression.
44	#define expect_false(expr) expect ((expr) != 0, 0)
45	#define expect_true(expr) expect ((expr) != 0, 1)
46
47	#include <cstddef>
48	#include <cmath>
49	#include <new>
50	#include <vector>
51
52	#include <glib.h>
53
54	#include <shstr.h>
55	#include <traits.h>
56
57	// use C0X decltype for auto declarations until ISO C++ sanctifies them (if ever)
58	#define auto(var,expr) decltype(expr) var = (expr)
59
60	// very ugly macro that basicaly declares and initialises a variable
61	// that is in scope for the next statement only
62	// works only for stuff that can be assigned 0 and converts to false
63	// (note: works great for pointers)
64	// most ugly macro I ever wrote
65	#define statementvar(type, name, value) if (type name = 0) { } else if (((name) = (value)), 1)
66
67	// in range including end
68	#define IN_RANGE_INC(val,beg,end) \
69	((unsigned int)(val) - (unsigned int)(beg) <= (unsigned int)(end) - (unsigned int)(beg))
70
71	// in range excluding end
72	#define IN_RANGE_EXC(val,beg,end) \
73	((unsigned int)(val) - (unsigned int)(beg) < (unsigned int)(end) - (unsigned int)(beg))
74
75	void fork_abort (const char *msg);
76
77	// rationale for using (U) not (T) is to reduce signed/unsigned issues,
78	// as a is often a constant while b is the variable. it is still a bug, though.
79	template<typename T, typename U> static inline T min (T a, U b) { return (U)a < b ? (U)a : b; }
80	template<typename T, typename U> static inline T max (T a, U b) { return (U)a > b ? (U)a : b; }
81	template<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; }
82
83	template<typename T, typename U> static inline void swap (T& a, U& b) { T t=a; a=(T)b; b=(U)t; }
84
85	template<typename T>
86	static inline T
87	lerp (T val, T min_in, T max_in, T min_out, T max_out)
88	{
89	return (val - min_in) * (max_out - min_out) / (max_in - min_in) + min_out;
90	}
91
92	// lots of stuff taken from FXT
93
94	/* Rotate right. This is used in various places for checksumming */
95	//TODO: that sucks, use a better checksum algo
96	static inline uint32_t
97	rotate_right (uint32_t c, uint32_t count = 1)
98	{
99	return (c << (32 - count)) \| (c >> count);
100	}
101
102	static inline uint32_t
103	rotate_left (uint32_t c, uint32_t count = 1)
104	{
105	return (c >> (32 - count)) \| (c << count);
106	}
107
108	// Return abs(a-b)
109	// Both a and b must not have the most significant bit set
110	static inline uint32_t
111	upos_abs_diff (uint32_t a, uint32_t b)
112	{
113	long d1 = b - a;
114	long d2 = (d1 & (d1 >> 31)) << 1;
115
116	return d1 - d2; // == (b - d) - (a + d);
117	}
118
119	// Both a and b must not have the most significant bit set
120	static inline uint32_t
121	upos_min (uint32_t a, uint32_t b)
122	{
123	int32_t d = b - a;
124	d &= d >> 31;
125	return a + d;
126	}
127
128	// Both a and b must not have the most significant bit set
129	static inline uint32_t
130	upos_max (uint32_t a, uint32_t b)
131	{
132	int32_t d = b - a;
133	d &= d >> 31;
134	return b - d;
135	}
136
137	// this is much faster than crossfires original algorithm
138	// on modern cpus
139	inline int
140	isqrt (int n)
141	{
142	return (int)sqrtf ((float)n);
143	}
144
145	// this is only twice as fast as naive sqrtf (dxdy+dydy)
146	#if 0
147	// and has a max. error of 6 in the range -100..+100.
148	#else
149	// and has a max. error of 9 in the range -100..+100.
150	#endif
151	inline int
152	idistance (int dx, int dy)
153	{
154	unsigned int dx_ = abs (dx);
155	unsigned int dy_ = abs (dy);
156
157	#if 0
158	return dx_ > dy_
159	? (dx_ * 61685 + dy_ * 26870) >> 16
160	: (dy_ * 61685 + dx_ * 26870) >> 16;
161	#else
162	return dx_ + dy_ - min (dx_, dy_) * 5 / 8;
163	#endif
164	}
165
166	/*
167	* absdir(int): Returns a number between 1 and 8, which represent
168	* the "absolute" direction of a number (it actually takes care of
169	* "overflow" in previous calculations of a direction).
170	*/
171	inline int
172	absdir (int d)
173	{
174	return ((d - 1) & 7) + 1;
175	}
176
177	extern size_t slice_alloc; // statistics
178
179	// makes dynamically allocated objects zero-initialised
180	struct zero_initialised
181	{
182	void operator new (size_t s, void p)
183	{
184	memset (p, 0, s);
185	return p;
186	}
187
188	void *operator new (size_t s)
189	{
190	slice_alloc += s;
191	return g_slice_alloc0 (s);
192	}
193
194	void *operator new[] (size_t s)
195	{
196	slice_alloc += s;
197	return g_slice_alloc0 (s);
198	}
199
200	void operator delete (void *p, size_t s)
201	{
202	slice_alloc -= s;
203	g_slice_free1 (s, p);
204	}
205
206	void operator delete[] (void *p, size_t s)
207	{
208	slice_alloc -= s;
209	g_slice_free1 (s, p);
210	}
211	};
212
213	void *salloc_ (int n) throw (std::bad_alloc);
214	void salloc_ (int n, void src) throw (std::bad_alloc);
215
216	// strictly the same as g_slice_alloc, but never returns 0
217	template<typename T>
218	inline T salloc (int n = 1) throw (std::bad_alloc) { return (T )salloc_ (n * sizeof (T)); }
219
220	// also copies src into the new area, like "memdup"
221	// if src is 0, clears the memory
222	template<typename T>
223	inline T salloc (int n, T src) throw (std::bad_alloc) { return (T )salloc_ (n sizeof (T), (void *)src); }
224
225	// clears the memory
226	template<typename T>
227	inline T salloc0(int n = 1) throw (std::bad_alloc) { return (T )salloc_ (n * sizeof (T), 0); }
228
229	// for symmetry
230	template<typename T>
231	inline void sfree (T *ptr, int n = 1) throw ()
232	{
233	#ifdef PREFER_MALLOC
234	free (ptr);
235	#else
236	slice_alloc -= n * sizeof (T);
237	g_slice_free1 (n * sizeof (T), (void *)ptr);
238	#endif
239	}
240
241	// a STL-compatible allocator that uses g_slice
242	// boy, this is verbose
243	template<typename Tp>
244	struct slice_allocator
245	{
246	typedef size_t size_type;
247	typedef ptrdiff_t difference_type;
248	typedef Tp *pointer;
249	typedef const Tp *const_pointer;
250	typedef Tp &reference;
251	typedef const Tp &const_reference;
252	typedef Tp value_type;
253
254	template <class U>
255	struct rebind
256	{
257	typedef slice_allocator<U> other;
258	};
259
260	slice_allocator () throw () { }
261	slice_allocator (const slice_allocator &o) throw () { }
262	template<typename Tp2>
263	slice_allocator (const slice_allocator<Tp2> &) throw () { }
264
265	~slice_allocator () { }
266
267	pointer address (reference x) const { return &x; }
268	const_pointer address (const_reference x) const { return &x; }
269
270	pointer allocate (size_type n, const_pointer = 0)
271	{
272	return salloc<Tp> (n);
273	}
274
275	void deallocate (pointer p, size_type n)
276	{
277	sfree<Tp> (p, n);
278	}
279
280	size_type max_size ()const throw ()
281	{
282	return size_t (-1) / sizeof (Tp);
283	}
284
285	void construct (pointer p, const Tp &val)
286	{
287	::new (p) Tp (val);
288	}
289
290	void destroy (pointer p)
291	{
292	p->~Tp ();
293	}
294	};
295
296	// P. L'Ecuyer, “Maximally Equidistributed Combined Tausworthe Generators”, Mathematics of Computation, 65, 213 (1996), 203–213.
297	// http://www.iro.umontreal.ca/~lecuyer/myftp/papers/tausme.ps
298	// http://www.iro.umontreal.ca/~lecuyer/myftp/papers/tausme2.ps
299	struct tausworthe_random_generator
300	{
301	// generator
302	uint32_t state [4];
303
304	void operator =(const tausworthe_random_generator &src)
305	{
306	state [0] = src.state [0];
307	state [1] = src.state [1];
308	state [2] = src.state [2];
309	state [3] = src.state [3];
310	}
311
312	void seed (uint32_t seed);
313	uint32_t next ();
314
315	// uniform distribution
316	uint32_t operator ()(uint32_t num)
317	{
318	return is_constant (num)
319	? (next () * (uint64_t)num) >> 32U
320	: get_range (num);
321	}
322
323	// return a number within (min .. max)
324	int operator () (int r_min, int r_max)
325	{
326	return is_constant (r_min) && is_constant (r_max) && r_min <= r_max
327	? r_min + operator ()(r_max - r_min + 1)
328	: get_range (r_min, r_max);
329	}
330
331	double operator ()()
332	{
333	return this->next () / (double)0xFFFFFFFFU;
334	}
335
336	protected:
337	uint32_t get_range (uint32_t r_max);
338	int get_range (int r_min, int r_max);
339	};
340
341	typedef tausworthe_random_generator rand_gen;
342
343	extern rand_gen rndm;
344
345	INTERFACE_CLASS (attachable)
346	struct refcnt_base
347	{
348	typedef int refcnt_t;
349	mutable refcnt_t ACC (RW, refcnt);
350
351	MTH void refcnt_inc () const { ++refcnt; }
352	MTH void refcnt_dec () const { --refcnt; }
353
354	refcnt_base () : refcnt (0) { }
355	};
356
357	// to avoid branches with more advanced compilers
358	extern refcnt_base::refcnt_t refcnt_dummy;
359
360	template<class T>
361	struct refptr
362	{
363	// p if not null
364	refcnt_base::refcnt_t *refcnt_ref () { return p ? &p->refcnt : &refcnt_dummy; }
365
366	void refcnt_dec ()
367	{
368	if (!is_constant (p))
369	--*refcnt_ref ();
370	else if (p)
371	--p->refcnt;
372	}
373
374	void refcnt_inc ()
375	{
376	if (!is_constant (p))
377	++*refcnt_ref ();
378	else if (p)
379	++p->refcnt;
380	}
381
382	T *p;
383
384	refptr () : p(0) { }
385	refptr (const refptr<T> &p) : p(p.p) { refcnt_inc (); }
386	refptr (T *p) : p(p) { refcnt_inc (); }
387	~refptr () { refcnt_dec (); }
388
389	const refptr<T> &operator =(T *o)
390	{
391	// if decrementing ever destroys we need to reverse the order here
392	refcnt_dec ();
393	p = o;
394	refcnt_inc ();
395	return *this;
396	}
397
398	const refptr<T> &operator =(const refptr<T> &o)
399	{
400	*this = o.p;
401	return *this;
402	}
403
404	T &operator * () const { return *p; }
405	T *operator ->() const { return p; }
406
407	operator T *() const { return p; }
408	};
409
410	typedef refptr<maptile> maptile_ptr;
411	typedef refptr<object> object_ptr;
412	typedef refptr<archetype> arch_ptr;
413	typedef refptr<client> client_ptr;
414	typedef refptr<player> player_ptr;
415
416	struct str_hash
417	{
418	std::size_t operator ()(const char *s) const
419	{
420	unsigned long hash = 0;
421
422	/* use the one-at-a-time hash function, which supposedly is
423	* better than the djb2-like one used by perl5.005, but
424	* certainly is better then the bug used here before.
425	* see http://burtleburtle.net/bob/hash/doobs.html
426	*/
427	while (*s)
428	{
429	hash += *s++;
430	hash += hash << 10;
431	hash ^= hash >> 6;
432	}
433
434	hash += hash << 3;
435	hash ^= hash >> 11;
436	hash += hash << 15;
437
438	return hash;
439	}
440	};
441
442	struct str_equal
443	{
444	bool operator ()(const char a, const char b) const
445	{
446	return !strcmp (a, b);
447	}
448	};
449
450	// Mostly the same as std::vector, but insert/erase can reorder
451	// the elements, making append(=insert)/remove O(1) instead of O(n).
452	//
453	// NOTE: only some forms of erase are available
454	template<class T>
455	struct unordered_vector : std::vector<T, slice_allocator<T> >
456	{
457	typedef typename unordered_vector::iterator iterator;
458
459	void erase (unsigned int pos)
460	{
461	if (pos < this->size () - 1)
462	(this)[pos] = (this)[this->size () - 1];
463
464	this->pop_back ();
465	}
466
467	void erase (iterator i)
468	{
469	erase ((unsigned int )(i - this->begin ()));
470	}
471	};
472
473	// This container blends advantages of linked lists
474	// (efficiency) with vectors (random access) by
475	// by using an unordered vector and storing the vector
476	// index inside the object.
477	//
478	// + memory-efficient on most 64 bit archs
479	// + O(1) insert/remove
480	// + free unique (but varying) id for inserted objects
481	// + cache-friendly iteration
482	// - only works for pointers to structs
483	//
484	// NOTE: only some forms of erase/insert are available
485	typedef int object_vector_index;
486
487	template<class T, object_vector_index T::*indexmember>
488	struct object_vector : std::vector<T , slice_allocator<T > >
489	{
490	typedef typename object_vector::iterator iterator;
491
492	bool contains (const T *obj) const
493	{
494	return obj->*indexmember;
495	}
496
497	iterator find (const T *obj)
498	{
499	return obj->*indexmember
500	? this->begin () + obj->*indexmember - 1
501	: this->end ();
502	}
503
504	void push_back (T *obj)
505	{
506	std::vector<T , slice_allocator<T > >::push_back (obj);
507	obj->*indexmember = this->size ();
508	}
509
510	void insert (T *obj)
511	{
512	push_back (obj);
513	}
514
515	void insert (T &obj)
516	{
517	insert (&obj);
518	}
519
520	void erase (T *obj)
521	{
522	unsigned int pos = obj->*indexmember;
523	obj->*indexmember = 0;
524
525	if (pos < this->size ())
526	{
527	(this)[pos - 1] = (this)[this->size () - 1];
528	(this)[pos - 1]->indexmember = pos;
529	}
530
531	this->pop_back ();
532	}
533
534	void erase (T &obj)
535	{
536	erase (&obj);
537	}
538	};
539
540	// basically does what strncpy should do, but appends "..." to strings exceeding length
541	void assign (char dst, const char src, int maxlen);
542
543	// type-safe version of assign
544	template<int N>
545	inline void assign (char (&dst)[N], const char *src)
546	{
547	assign ((char *)&dst, src, N);
548	}
549
550	typedef double tstamp;
551
552	// return current time as timestamp
553	tstamp now ();
554
555	int similar_direction (int a, int b);
556
557	// like sprintf, but returns a "static" buffer
558	const char format (const char format, ...);
559
560	#endif
561