server/include/util.h

#ifndef UTIL_H__
#define UTIL_H__

#if __GNUC__ >= 3
# define is_constant(c) __builtin_constant_p (c)
#else
# define is_constant(c) 0
#endif

#include <cstddef>

#include <glib.h>

// 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)
  {
    return g_slice_alloc0 (s);
  }

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

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

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

void throw_bad_alloc () throw (std::bad_alloc);

void *alloc (int s) throw (std::bad_alloc);
void dealloc (void *p, int s) throw ();

// 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 static_cast<pointer>(alloc (n * sizeof (Tp)));
  }

  void deallocate (pointer p, size_type n)
  {
    dealloc (static_cast<void *>(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 ();
  }
};

struct refcounted
{
  mutable int refcnt;
  refcounted () : refcnt (0) { }
  void refcnt_inc () { ++refcnt; }
  void refcnt_dec () { --refcnt;
  if (refcnt < 0)abort();}//D
};

template<class T>
struct refptr
{
  T *p;

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

  const refptr<T> &operator =(T *o)
  {
    if (p) p->refcnt_dec ();
    p = o;
    if (p) p->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; }
};

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);
  }
};

#include <vector>

template<class obj>
struct unordered_vector : std::vector<obj, slice_allocator<obj> >
{
  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 ()));
  }
};

template<typename T, typename U> static inline T min (T a, U b) { return a < (T)b ? a : (T)b; }
template<typename T, typename U> static inline T max (T a, U b) { return a > (T)b ? a : (T)b; }
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; }

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

// 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);
}

#endif

Revision:	1.11
Committed:	Tue Sep 12 20:55:40 2006 UTC (17 years, 8 months ago) by root
Content type:	text/plain
Branch:	MAIN
Changes since 1.10:	+91 -7 lines
Log Message:	make use of slice_allocator and inline zero_initialised
#	User	Rev	Content
1	root	1.1	#ifndef UTIL_H__
2			#define UTIL_H__
3
4	root	1.2	#if __GNUC__ >= 3
5			# define is_constant(c) __builtin_constant_p (c)
6			#else
7			# define is_constant(c) 0
8			#endif
9
10	root	1.11	#include <cstddef>
11
12			#include <glib.h>
13
14	root	1.1	// makes dynamically allocated objects zero-initialised
15			struct zero_initialised
16			{
17	root	1.11	void operator new (size_t s, void p)
18			{
19			memset (p, 0, s);
20			return p;
21			}
22
23			void *operator new (size_t s)
24			{
25			return g_slice_alloc0 (s);
26			}
27
28			void *operator new[] (size_t s)
29			{
30			return g_slice_alloc0 (s);
31			}
32
33			void operator delete (void *p, size_t s)
34			{
35			g_slice_free1 (s, p);
36			}
37
38			void operator delete[] (void *p, size_t s)
39			{
40			g_slice_free1 (s, p);
41			}
42			};
43
44			void throw_bad_alloc () throw (std::bad_alloc);
45
46			void *alloc (int s) throw (std::bad_alloc);
47			void dealloc (void *p, int s) throw ();
48
49			// a STL-compatible allocator that uses g_slice
50			// boy, this is verbose
51			template<typename Tp>
52			struct slice_allocator
53			{
54			typedef size_t size_type;
55			typedef ptrdiff_t difference_type;
56			typedef Tp *pointer;
57			typedef const Tp *const_pointer;
58			typedef Tp &reference;
59			typedef const Tp &const_reference;
60			typedef Tp value_type;
61
62			template <class U>
63			struct rebind
64			{
65			typedef slice_allocator<U> other;
66			};
67
68			slice_allocator () throw () { }
69			slice_allocator (const slice_allocator &o) throw () { }
70			template<typename Tp2>
71			slice_allocator (const slice_allocator<Tp2> &) throw () { }
72
73			~slice_allocator () { }
74
75			pointer address (reference x) const { return &x; }
76			const_pointer address (const_reference x) const { return &x; }
77
78			pointer allocate (size_type n, const_pointer = 0)
79			{
80			return static_cast<pointer>(alloc (n * sizeof (Tp)));
81			}
82
83			void deallocate (pointer p, size_type n)
84			{
85			dealloc (static_cast<void *>(p), n);
86			}
87
88			size_type max_size ()const throw ()
89			{
90			return size_t (-1) / sizeof (Tp);
91			}
92
93			void construct (pointer p, const Tp &val)
94			{
95			::new (p) Tp (val);
96			}
97
98			void destroy (pointer p)
99			{
100			p->~Tp ();
101			}
102	root	1.1	};
103
104	root	1.7	struct refcounted
105			{
106			mutable int refcnt;
107			refcounted () : refcnt (0) { }
108			void refcnt_inc () { ++refcnt; }
109			void refcnt_dec () { --refcnt;
110			if (refcnt < 0)abort();}//D
111			};
112
113			template<class T>
114			struct refptr
115			{
116			T *p;
117
118			refptr () : p(0) { }
119			refptr (const refptr<T> &p) : p(p.p) { if (p) p->refcnt_inc (); }
120			refptr (T *p) : p(p) { if (p) p->refcnt_inc (); }
121			~refptr () { if (p) p->refcnt_dec (); }
122
123			const refptr<T> &operator =(T *o)
124			{
125			if (p) p->refcnt_dec ();
126			p = o;
127			if (p) p->refcnt_inc ();
128
129			return *this;
130			}
131
132			const refptr<T> &operator =(const refptr<T> o)
133			{
134			*this = o.p;
135			return *this;
136			}
137
138			T &operator * () const { return *p; }
139			T *operator ->() const { return p; }
140
141			operator T *() const { return p; }
142			};
143
144	root	1.4	struct str_hash
145			{
146			std::size_t operator ()(const char *s) const
147			{
148			unsigned long hash = 0;
149
150			/* use the one-at-a-time hash function, which supposedly is
151			* better than the djb2-like one used by perl5.005, but
152			* certainly is better then the bug used here before.
153			* see http://burtleburtle.net/bob/hash/doobs.html
154			*/
155			while (*s)
156			{
157			hash += *s++;
158			hash += hash << 10;
159			hash ^= hash >> 6;
160			}
161
162			hash += hash << 3;
163			hash ^= hash >> 11;
164			hash += hash << 15;
165
166			return hash;
167			}
168			};
169
170			struct str_equal
171			{
172			bool operator ()(const char a, const char b) const
173			{
174			return !strcmp (a, b);
175			}
176			};
177
178	root	1.6	#include <vector>
179
180			template<class obj>
181	root	1.11	struct unordered_vector : std::vector<obj, slice_allocator<obj> >
182	root	1.6	{
183	root	1.11	typedef typename unordered_vector::iterator iterator;
184	root	1.6
185			void erase (unsigned int pos)
186			{
187			if (pos < this->size () - 1)
188			(this)[pos] = (this)[this->size () - 1];
189
190			this->pop_back ();
191			}
192
193			void erase (iterator i)
194			{
195			erase ((unsigned int )(i - this->begin ()));
196			}
197			};
198
199	root	1.8	template<typename T, typename U> static inline T min (T a, U b) { return a < (T)b ? a : (T)b; }
200			template<typename T, typename U> static inline T max (T a, U b) { return a > (T)b ? a : (T)b; }
201			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; }
202
203			template<typename T, typename U> static inline void swap (T& a, U& b) { T t=a; a=(T)b; b=(U)t; }
204
205	root	1.10	// basically does what strncpy should do, but appends "..." to strings exceeding length
206			void assign (char dst, const char src, int maxlen);
207
208			// type-safe version of assign
209	root	1.9	template<int N>
210			inline void assign (char (&dst)[N], const char *src)
211			{
212	root	1.10	assign ((char *)&dst, src, N);
213	root	1.9	}
214
215	root	1.1	#endif
216