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 DEBUG_SALLOC 0
#define PREFER_MALLOC 0

#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>

#if DEBUG_SALLOC
# define g_slice_alloc0(s) debug_slice_alloc0(s)
# define g_slice_alloc(s) debug_slice_alloc(s)
# define g_slice_free1(s,p) debug_slice_free1(s,p)
void *g_slice_alloc (unsigned long size);
void *g_slice_alloc0 (unsigned long size);
void g_slice_free1 (unsigned long size, void *ptr);
#endif

// 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, typename U, typename V> static inline T min (T a, U b, V c) { return min (a, min (b, c)); }
template<typename T, typename U, typename V> static inline T max (T a, U b, V c) { return max (a, max (b, c)); }

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 ()
{
#if 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 &) 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:	1.65
Committed:	Tue Apr 1 19:50:38 2008 UTC (16 years, 1 month ago) by root
Content type:	text/plain
Branch:	MAIN
Changes since 1.64:	+4 -4 lines
Log Message:	tuning, glibc-bugworkaround
#	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 DEBUG_SALLOC 0
26	#define PREFER_MALLOC 0
27
28	#if __GNUC__ >= 3
29	# define is_constant(c) __builtin_constant_p (c)
30	# define expect(expr,value) __builtin_expect ((expr),(value))
31	# define prefetch(addr,rw,locality) __builtin_prefetch (addr, rw, locality)
32	#else
33	# define is_constant(c) 0
34	# define expect(expr,value) (expr)
35	# define prefetch(addr,rw,locality)
36	#endif
37
38	#if __GNUC__ < 4 \|\| (__GNUC__ == 4 \|\| __GNUC_MINOR__ < 4)
39	# define decltype(x) typeof(x)
40	#endif
41
42	// put into ifs if you are very sure that the expression
43	// is mostly true or mosty false. note that these return
44	// booleans, not the expression.
45	#define expect_false(expr) expect ((expr) != 0, 0)
46	#define expect_true(expr) expect ((expr) != 0, 1)
47
48	#include <cstddef>
49	#include <cmath>
50	#include <new>
51	#include <vector>
52
53	#include <glib.h>
54
55	#include <shstr.h>
56	#include <traits.h>
57
58	#if DEBUG_SALLOC
59	# define g_slice_alloc0(s) debug_slice_alloc0(s)
60	# define g_slice_alloc(s) debug_slice_alloc(s)
61	# define g_slice_free1(s,p) debug_slice_free1(s,p)
62	void *g_slice_alloc (unsigned long size);
63	void *g_slice_alloc0 (unsigned long size);
64	void g_slice_free1 (unsigned long size, void *ptr);
65	#endif
66
67	// use C0X decltype for auto declarations until ISO C++ sanctifies them (if ever)
68	#define auto(var,expr) decltype(expr) var = (expr)
69
70	// very ugly macro that basicaly declares and initialises a variable
71	// that is in scope for the next statement only
72	// works only for stuff that can be assigned 0 and converts to false
73	// (note: works great for pointers)
74	// most ugly macro I ever wrote
75	#define statementvar(type, name, value) if (type name = 0) { } else if (((name) = (value)), 1)
76
77	// in range including end
78	#define IN_RANGE_INC(val,beg,end) \
79	((unsigned int)(val) - (unsigned int)(beg) <= (unsigned int)(end) - (unsigned int)(beg))
80
81	// in range excluding end
82	#define IN_RANGE_EXC(val,beg,end) \
83	((unsigned int)(val) - (unsigned int)(beg) < (unsigned int)(end) - (unsigned int)(beg))
84
85	void fork_abort (const char *msg);
86
87	// rationale for using (U) not (T) is to reduce signed/unsigned issues,
88	// as a is often a constant while b is the variable. it is still a bug, though.
89	template<typename T, typename U> static inline T min (T a, U b) { return (U)a < b ? (U)a : b; }
90	template<typename T, typename U> static inline T max (T a, U b) { return (U)a > b ? (U)a : b; }
91	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; }
92
93	template<typename T, typename U> static inline void swap (T& a, U& b) { T t=a; a=(T)b; b=(U)t; }
94
95	template<typename T, typename U, typename V> static inline T min (T a, U b, V c) { return min (a, min (b, c)); }
96	template<typename T, typename U, typename V> static inline T max (T a, U b, V c) { return max (a, max (b, c)); }
97
98	template<typename T>
99	static inline T
100	lerp (T val, T min_in, T max_in, T min_out, T max_out)
101	{
102	return (val - min_in) * (max_out - min_out) / (max_in - min_in) + min_out;
103	}
104
105	// lots of stuff taken from FXT
106
107	/* Rotate right. This is used in various places for checksumming */
108	//TODO: that sucks, use a better checksum algo
109	static inline uint32_t
110	rotate_right (uint32_t c, uint32_t count = 1)
111	{
112	return (c << (32 - count)) \| (c >> count);
113	}
114
115	static inline uint32_t
116	rotate_left (uint32_t c, uint32_t count = 1)
117	{
118	return (c >> (32 - count)) \| (c << count);
119	}
120
121	// Return abs(a-b)
122	// Both a and b must not have the most significant bit set
123	static inline uint32_t
124	upos_abs_diff (uint32_t a, uint32_t b)
125	{
126	long d1 = b - a;
127	long d2 = (d1 & (d1 >> 31)) << 1;
128
129	return d1 - d2; // == (b - d) - (a + d);
130	}
131
132	// Both a and b must not have the most significant bit set
133	static inline uint32_t
134	upos_min (uint32_t a, uint32_t b)
135	{
136	int32_t d = b - a;
137	d &= d >> 31;
138	return a + d;
139	}
140
141	// Both a and b must not have the most significant bit set
142	static inline uint32_t
143	upos_max (uint32_t a, uint32_t b)
144	{
145	int32_t d = b - a;
146	d &= d >> 31;
147	return b - d;
148	}
149
150	// this is much faster than crossfires original algorithm
151	// on modern cpus
152	inline int
153	isqrt (int n)
154	{
155	return (int)sqrtf ((float)n);
156	}
157
158	// this is only twice as fast as naive sqrtf (dxdy+dydy)
159	#if 0
160	// and has a max. error of 6 in the range -100..+100.
161	#else
162	// and has a max. error of 9 in the range -100..+100.
163	#endif
164	inline int
165	idistance (int dx, int dy)
166	{
167	unsigned int dx_ = abs (dx);
168	unsigned int dy_ = abs (dy);
169
170	#if 0
171	return dx_ > dy_
172	? (dx_ * 61685 + dy_ * 26870) >> 16
173	: (dy_ * 61685 + dx_ * 26870) >> 16;
174	#else
175	return dx_ + dy_ - min (dx_, dy_) * 5 / 8;
176	#endif
177	}
178
179	/*
180	* absdir(int): Returns a number between 1 and 8, which represent
181	* the "absolute" direction of a number (it actually takes care of
182	* "overflow" in previous calculations of a direction).
183	*/
184	inline int
185	absdir (int d)
186	{
187	return ((d - 1) & 7) + 1;
188	}
189
190	extern size_t slice_alloc; // statistics
191
192	// makes dynamically allocated objects zero-initialised
193	struct zero_initialised
194	{
195	void operator new (size_t s, void p)
196	{
197	memset (p, 0, s);
198	return p;
199	}
200
201	void *operator new (size_t s)
202	{
203	slice_alloc += s;
204	return g_slice_alloc0 (s);
205	}
206
207	void *operator new[] (size_t s)
208	{
209	slice_alloc += s;
210	return g_slice_alloc0 (s);
211	}
212
213	void operator delete (void *p, size_t s)
214	{
215	slice_alloc -= s;
216	g_slice_free1 (s, p);
217	}
218
219	void operator delete[] (void *p, size_t s)
220	{
221	slice_alloc -= s;
222	g_slice_free1 (s, p);
223	}
224	};
225
226	void *salloc_ (int n) throw (std::bad_alloc);
227	void salloc_ (int n, void src) throw (std::bad_alloc);
228
229	// strictly the same as g_slice_alloc, but never returns 0
230	template<typename T>
231	inline T salloc (int n = 1) throw (std::bad_alloc) { return (T )salloc_ (n * sizeof (T)); }
232
233	// also copies src into the new area, like "memdup"
234	// if src is 0, clears the memory
235	template<typename T>
236	inline T salloc (int n, T src) throw (std::bad_alloc) { return (T )salloc_ (n sizeof (T), (void *)src); }
237
238	// clears the memory
239	template<typename T>
240	inline T salloc0(int n = 1) throw (std::bad_alloc) { return (T )salloc_ (n * sizeof (T), 0); }
241
242	// for symmetry
243	template<typename T>
244	inline void sfree (T *ptr, int n = 1) throw ()
245	{
246	#if PREFER_MALLOC
247	free (ptr);
248	#else
249	slice_alloc -= n * sizeof (T);
250	g_slice_free1 (n * sizeof (T), (void *)ptr);
251	#endif
252	}
253
254	// a STL-compatible allocator that uses g_slice
255	// boy, this is verbose
256	template<typename Tp>
257	struct slice_allocator
258	{
259	typedef size_t size_type;
260	typedef ptrdiff_t difference_type;
261	typedef Tp *pointer;
262	typedef const Tp *const_pointer;
263	typedef Tp &reference;
264	typedef const Tp &const_reference;
265	typedef Tp value_type;
266
267	template <class U>
268	struct rebind
269	{
270	typedef slice_allocator<U> other;
271	};
272
273	slice_allocator () throw () { }
274	slice_allocator (const slice_allocator &) throw () { }
275	template<typename Tp2>
276	slice_allocator (const slice_allocator<Tp2> &) throw () { }
277
278	~slice_allocator () { }
279
280	pointer address (reference x) const { return &x; }
281	const_pointer address (const_reference x) const { return &x; }
282
283	pointer allocate (size_type n, const_pointer = 0)
284	{
285	return salloc<Tp> (n);
286	}
287
288	void deallocate (pointer p, size_type n)
289	{
290	sfree<Tp> (p, n);
291	}
292
293	size_type max_size () const throw ()
294	{
295	return size_t (-1) / sizeof (Tp);
296	}
297
298	void construct (pointer p, const Tp &val)
299	{
300	::new (p) Tp (val);
301	}
302
303	void destroy (pointer p)
304	{
305	p->~Tp ();
306	}
307	};
308
309	// P. L'Ecuyer, “Maximally Equidistributed Combined Tausworthe Generators”, Mathematics of Computation, 65, 213 (1996), 203–213.
310	// http://www.iro.umontreal.ca/~lecuyer/myftp/papers/tausme.ps
311	// http://www.iro.umontreal.ca/~lecuyer/myftp/papers/tausme2.ps
312	struct tausworthe_random_generator
313	{
314	// generator
315	uint32_t state [4];
316
317	void operator =(const tausworthe_random_generator &src)
318	{
319	state [0] = src.state [0];
320	state [1] = src.state [1];
321	state [2] = src.state [2];
322	state [3] = src.state [3];
323	}
324
325	void seed (uint32_t seed);
326	uint32_t next ();
327
328	// uniform distribution
329	uint32_t operator ()(uint32_t num)
330	{
331	return is_constant (num)
332	? (next () * (uint64_t)num) >> 32U
333	: get_range (num);
334	}
335
336	// return a number within (min .. max)
337	int operator () (int r_min, int r_max)
338	{
339	return is_constant (r_min) && is_constant (r_max) && r_min <= r_max
340	? r_min + operator ()(r_max - r_min + 1)
341	: get_range (r_min, r_max);
342	}
343
344	double operator ()()
345	{
346	return this->next () / (double)0xFFFFFFFFU;
347	}
348
349	protected:
350	uint32_t get_range (uint32_t r_max);
351	int get_range (int r_min, int r_max);
352	};
353
354	typedef tausworthe_random_generator rand_gen;
355
356	extern rand_gen rndm;
357
358	INTERFACE_CLASS (attachable)
359	struct refcnt_base
360	{
361	typedef int refcnt_t;
362	mutable refcnt_t ACC (RW, refcnt);
363
364	MTH void refcnt_inc () const { ++refcnt; }
365	MTH void refcnt_dec () const { --refcnt; }
366
367	refcnt_base () : refcnt (0) { }
368	};
369
370	// to avoid branches with more advanced compilers
371	extern refcnt_base::refcnt_t refcnt_dummy;
372
373	template<class T>
374	struct refptr
375	{
376	// p if not null
377	refcnt_base::refcnt_t *refcnt_ref () { return p ? &p->refcnt : &refcnt_dummy; }
378
379	void refcnt_dec ()
380	{
381	if (!is_constant (p))
382	--*refcnt_ref ();
383	else if (p)
384	--p->refcnt;
385	}
386
387	void refcnt_inc ()
388	{
389	if (!is_constant (p))
390	++*refcnt_ref ();
391	else if (p)
392	++p->refcnt;
393	}
394
395	T *p;
396
397	refptr () : p(0) { }
398	refptr (const refptr<T> &p) : p(p.p) { refcnt_inc (); }
399	refptr (T *p) : p(p) { refcnt_inc (); }
400	~refptr () { refcnt_dec (); }
401
402	const refptr<T> &operator =(T *o)
403	{
404	// if decrementing ever destroys we need to reverse the order here
405	refcnt_dec ();
406	p = o;
407	refcnt_inc ();
408	return *this;
409	}
410
411	const refptr<T> &operator =(const refptr<T> &o)
412	{
413	*this = o.p;
414	return *this;
415	}
416
417	T &operator * () const { return *p; }
418	T *operator ->() const { return p; }
419
420	operator T *() const { return p; }
421	};
422
423	typedef refptr<maptile> maptile_ptr;
424	typedef refptr<object> object_ptr;
425	typedef refptr<archetype> arch_ptr;
426	typedef refptr<client> client_ptr;
427	typedef refptr<player> player_ptr;
428
429	struct str_hash
430	{
431	std::size_t operator ()(const char *s) const
432	{
433	unsigned long hash = 0;
434
435	/* use the one-at-a-time hash function, which supposedly is
436	* better than the djb2-like one used by perl5.005, but
437	* certainly is better then the bug used here before.
438	* see http://burtleburtle.net/bob/hash/doobs.html
439	*/
440	while (*s)
441	{
442	hash += *s++;
443	hash += hash << 10;
444	hash ^= hash >> 6;
445	}
446
447	hash += hash << 3;
448	hash ^= hash >> 11;
449	hash += hash << 15;
450
451	return hash;
452	}
453	};
454
455	struct str_equal
456	{
457	bool operator ()(const char a, const char b) const
458	{
459	return !strcmp (a, b);
460	}
461	};
462
463	// Mostly the same as std::vector, but insert/erase can reorder
464	// the elements, making append(=insert)/remove O(1) instead of O(n).
465	//
466	// NOTE: only some forms of erase are available
467	template<class T>
468	struct unordered_vector : std::vector<T, slice_allocator<T> >
469	{
470	typedef typename unordered_vector::iterator iterator;
471
472	void erase (unsigned int pos)
473	{
474	if (pos < this->size () - 1)
475	(this)[pos] = (this)[this->size () - 1];
476
477	this->pop_back ();
478	}
479
480	void erase (iterator i)
481	{
482	erase ((unsigned int )(i - this->begin ()));
483	}
484	};
485
486	// This container blends advantages of linked lists
487	// (efficiency) with vectors (random access) by
488	// by using an unordered vector and storing the vector
489	// index inside the object.
490	//
491	// + memory-efficient on most 64 bit archs
492	// + O(1) insert/remove
493	// + free unique (but varying) id for inserted objects
494	// + cache-friendly iteration
495	// - only works for pointers to structs
496	//
497	// NOTE: only some forms of erase/insert are available
498	typedef int object_vector_index;
499
500	template<class T, object_vector_index T::*indexmember>
501	struct object_vector : std::vector<T , slice_allocator<T > >
502	{
503	typedef typename object_vector::iterator iterator;
504
505	bool contains (const T *obj) const
506	{
507	return obj->*indexmember;
508	}
509
510	iterator find (const T *obj)
511	{
512	return obj->*indexmember
513	? this->begin () + obj->*indexmember - 1
514	: this->end ();
515	}
516
517	void push_back (T *obj)
518	{
519	std::vector<T , slice_allocator<T > >::push_back (obj);
520	obj->*indexmember = this->size ();
521	}
522
523	void insert (T *obj)
524	{
525	push_back (obj);
526	}
527
528	void insert (T &obj)
529	{
530	insert (&obj);
531	}
532
533	void erase (T *obj)
534	{
535	unsigned int pos = obj->*indexmember;
536	obj->*indexmember = 0;
537
538	if (pos < this->size ())
539	{
540	(this)[pos - 1] = (this)[this->size () - 1];
541	(this)[pos - 1]->indexmember = pos;
542	}
543
544	this->pop_back ();
545	}
546
547	void erase (T &obj)
548	{
549	erase (&obj);
550	}
551	};
552
553	// basically does what strncpy should do, but appends "..." to strings exceeding length
554	void assign (char dst, const char src, int maxlen);
555
556	// type-safe version of assign
557	template<int N>
558	inline void assign (char (&dst)[N], const char *src)
559	{
560	assign ((char *)&dst, src, N);
561	}
562
563	typedef double tstamp;
564
565	// return current time as timestamp
566	tstamp now ();
567
568	int similar_direction (int a, int b);
569
570	// like sprintf, but returns a "static" buffer
571	const char format (const char format, ...);
572
573	#endif
574