ermyth/include/util.h

#ifndef UTIL_H
#define UTIL_H

#include <climits>
#include <cstddef>
#include <vector>

#include <ermyth/exception.h>

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

  void *operator new[] (size_t s)
  {
    void *p = malloc (s);
    memset (p, 0, s);
    return p;
  }

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

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

/**
 * Mostly the same as std::vector, but erase can reorder
 * the elements, making insert/remove O(1) instead of O(n).
 *
 * NOTE: only some forms of erase are available
 * (Taken from Crossfire TRT http://cf.schmorp.de/)
 */
template<typename T, typename Alloc = std::allocator<T> >
struct unordered_vector : std::vector<T, Alloc>
{
  typedef typename unordered_vector::iterator iterator;

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

    this->pop_back ();
  }

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

  void insert (T const &val)
  {
    push_back (val);
  }
};

/**
 * The following templates find a sufficiently large integer type to contain
 * the given number of bits.
 *
 * Usage:
 *
 * unsigned_type<16>::type a; // 16-bit unsigned if available (probably unsigned short)
 * signed_type<8>::type a; // 8-bit signed if available (probably char)
 */

// Empty class if everything failed
struct empty_base
{
};

// To allow inheritance from this and get the integer type out
template<typename T>
struct identity
{
  typedef T type;
};

/**
 * The following two templates are a compile-time if-statement.
 */
template<bool Cond, class Then, class Else>
struct If
{
  typedef Then ret;
};

template<class Then, class Else>
struct If<false, Then, Else>
{
  typedef Else ret;
};

// Looks whether the desired type exists
template<typename T, std::size_t bits, typename Else>
struct type_if_size
: If<sizeof (T) * CHAR_BIT >= bits, identity<T>, Else>::ret
{
};

template<std::size_t bits>
struct unsigned_type
: type_if_size<unsigned char, bits,
    type_if_size<unsigned short, bits,
      type_if_size<unsigned int, bits,
        type_if_size<unsigned long, bits,
          empty_base // No such type
        >
      >
    >
  >
{
};

template<std::size_t bits>
struct signed_type
: type_if_size<signed char, bits
  , type_if_size<signed short, bits
    , type_if_size<signed int, bits
      , type_if_size<signed long, bits
        , empty_base // No such type
        >
      >
    >
  >
{
};

template<class T, int T::*index = &T::index, class Alloc = std::allocator<T *> >
struct indexing_vector : std::vector<T *, Alloc>
{
  typedef typename indexing_vector::size_type size_type;
  typedef typename indexing_vector::iterator iterator;
  
  void erase (T *obj)
  {
    size_type pos = obj->*index - 1;
    obj->*index = 0;

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

    this->pop_back ();
  }

  void insert (T *obj)
  {
    this->push_back (obj);
    obj->*index = this->size ();
  }
};

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

    // use the one-at-a-time hash function.
    // 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_eq
{
  bool operator () (char const * const s1, char const * const s2) const
  {
    if (s1 == NULL || s2 == NULL)
      throw nullpointer_exception ();
    return !strcmp (s1, s2);
  }
};

struct str_lt
{
  bool operator () (char const * const s1, char const * const s2) const
  {
    if (s1 == NULL || s2 == NULL)
      throw nullpointer_exception ();
    return strcmp (s1, s2) < 0;
  }
};

#endif
Revision:	1.2
Committed:	Tue Aug 28 17:12:24 2007 UTC (19 years ago) by pippijn
Content type:	text/plain
Branch:	MAIN
CVS Tags:	HEAD
Changes since 1.1:	+0 -0 lines
State:	*FILE REMOVED*
Log Message:	removed old files
#	Content
1	#ifndef UTIL_H
2	#define UTIL_H
3
4	#include <climits>
5	#include <cstddef>
6	#include <vector>
7
8	#include <ermyth/exception.h>
9
10	// makes dynamically allocated objects zero-initialised
11	struct zero_initialised
12	{
13	void *operator new (size_t s)
14	{
15	void *p = malloc (s);
16	memset (p, 0, s);
17	return p;
18	}
19
20	void *operator new[] (size_t s)
21	{
22	void *p = malloc (s);
23	memset (p, 0, s);
24	return p;
25	}
26
27	void operator delete (void *p, size_t s)
28	{
29	free (p);
30	}
31
32	void operator delete[] (void *p, size_t s)
33	{
34	free (p);
35	}
36	};
37
38	/**
39	* Mostly the same as std::vector, but erase can reorder
40	* the elements, making insert/remove O(1) instead of O(n).
41	*
42	* NOTE: only some forms of erase are available
43	* (Taken from Crossfire TRT http://cf.schmorp.de/)
44	*/
45	template<typename T, typename Alloc = std::allocator<T> >
46	struct unordered_vector : std::vector<T, Alloc>
47	{
48	typedef typename unordered_vector::iterator iterator;
49
50	void erase (unsigned pos)
51	{
52	if (pos < this->size () - 1)
53	(this)[pos] = (this)[this->size () - 1];
54
55	this->pop_back ();
56	}
57
58	void erase (iterator pos)
59	{
60	erase ((unsigned)(pos - this->begin ()));
61	}
62
63	void insert (T const &val)
64	{
65	push_back (val);
66	}
67	};
68
69	/**
70	* The following templates find a sufficiently large integer type to contain
71	* the given number of bits.
72	*
73	* Usage:
74	*
75	* unsigned_type<16>::type a; // 16-bit unsigned if available (probably unsigned short)
76	* signed_type<8>::type a; // 8-bit signed if available (probably char)
77	*/
78
79	// Empty class if everything failed
80	struct empty_base
81	{
82	};
83
84	// To allow inheritance from this and get the integer type out
85	template<typename T>
86	struct identity
87	{
88	typedef T type;
89	};
90
91	/**
92	* The following two templates are a compile-time if-statement.
93	*/
94	template<bool Cond, class Then, class Else>
95	struct If
96	{
97	typedef Then ret;
98	};
99
100	template<class Then, class Else>
101	struct If<false, Then, Else>
102	{
103	typedef Else ret;
104	};
105
106	// Looks whether the desired type exists
107	template<typename T, std::size_t bits, typename Else>
108	struct type_if_size
109	: If<sizeof (T) * CHAR_BIT >= bits, identity<T>, Else>::ret
110	{
111	};
112
113	template<std::size_t bits>
114	struct unsigned_type
115	: type_if_size<unsigned char, bits,
116	type_if_size<unsigned short, bits,
117	type_if_size<unsigned int, bits,
118	type_if_size<unsigned long, bits,
119	empty_base // No such type
120	>
121	>
122	>
123	>
124	{
125	};
126
127	template<std::size_t bits>
128	struct signed_type
129	: type_if_size<signed char, bits
130	, type_if_size<signed short, bits
131	, type_if_size<signed int, bits
132	, type_if_size<signed long, bits
133	, empty_base // No such type
134	>
135	>
136	>
137	>
138	{
139	};
140
141	template<class T, int T::index = &T::index, class Alloc = std::allocator<T > >
142	struct indexing_vector : std::vector<T *, Alloc>
143	{
144	typedef typename indexing_vector::size_type size_type;
145	typedef typename indexing_vector::iterator iterator;
146
147	void erase (T *obj)
148	{
149	size_type pos = obj->*index - 1;
150	obj->*index = 0;
151
152	if (pos <= this->size ())
153	{
154	(this)[pos] = (this)[this->size () - 1];
155	(this)[pos]->index = pos;
156	}
157
158	this->pop_back ();
159	}
160
161	void insert (T *obj)
162	{
163	this->push_back (obj);
164	obj->*index = this->size ();
165	}
166	};
167
168	struct str_hash
169	{
170	std::size_t operator () (char const *s) const
171	{
172	unsigned long hash = 0;
173
174	// use the one-at-a-time hash function.
175	// see http://burtleburtle.net/bob/hash/doobs.html
176	while (*s)
177	{
178	hash += *s++;
179	hash += hash << 10;
180	hash ^= hash >> 6;
181	}
182
183	hash += hash << 3;
184	hash ^= hash >> 11;
185	hash += hash << 15;
186
187	return hash;
188	}
189	};
190
191	struct str_eq
192	{
193	bool operator () (char const * const s1, char const * const s2) const
194	{
195	if (s1 == NULL \|\| s2 == NULL)
196	throw nullpointer_exception ();
197	return !strcmp (s1, s2);
198	}
199	};
200
201	struct str_lt
202	{
203	bool operator () (char const * const s1, char const * const s2) const
204	{
205	if (s1 == NULL \|\| s2 == NULL)
206	throw nullpointer_exception ();
207	return strcmp (s1, s2) < 0;
208	}
209	};
210
211	#endif