include/common/util.h

/*
 * Copyright © 2007 Pippijn van Steenhoven / The Ermyth Team
 * Rights to this code are as documented in doc/pod/license.pod.
 *
 * Various utility functions.
 *
 * $Id: util.h,v 1.4 2007-08-30 19:56:20 pippijn Exp $
 */

#ifndef UTIL_H
#define UTIL_H

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

#include <ermyth/exception.h>

/**
 * 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
        >
      >
    >
  >
{
};

// This is a vector that stores each element's index in the object.
// This only works for pointers to objects.
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;
  
  iterator find (const T *obj)
  {
    return obj->*index
      ? this->begin () + obj->*index - 1
      : this->end ();
  }

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

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

E int irccasecmp (char const * const s1, char const * const s2);
E int ircncasecmp (char const * const s1, char const * const s2, int maxlen);

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

typedef double tstamp;

inline tstamp
now ()
{
#ifdef HAVE_GETTIMEOFDAY
  struct timeval tv;

  gettimeofday (&tv, 0);
  return tstamp (tv.tv_sec) + tstamp (tv.tv_usec) * tstamp (1e-6);
#else
  return tstamp (time (NULL));
#endif
}

#if 0
/**
 * Comma delimited output to std::cout
 */

namespace impl
{
  struct C
  {
    template<typename T>
    C operator << (T const &t) const
    {
      std::cout << ", " << t;
      return C();
    }
    
    C operator << (std::ostream &(* const f) (std::ostream &)) const
    {
      std::cout << f;
      return C();
    }
    
    C operator << (std::ios_base &(* const f) (std::ios_base &)) const
    {
      std::cout << f;
      return C();
    }
  };

  enum Del
  {
    del
  };
  
  template<typename T>
  C operator << (Del, T const &t)
  {
    std::cout << t;
    return C();
  }
  
  inline Del
  operator << (Del, std::ostream &(* const f) (std::ostream &))
  {
    std::cout << f;
    return del;
  }
  
  inline Del
  operator << (Del, std::ios_base &(* const f) (std::ios_base &))
  {
    std::cout << f;
    return del;
  }

  // The <<'s taking std::ios_base&(std::ios_base&)'s are for things like std::hex.
  // The <<'s taking std::ostream&(std::ostream&)'s are for things like std::endl.

  inline Del
  operator << (std::ostream &, Del)
  {
    return del;
  }
  // To allow: std::cout << del << 2 << 4
}

using impl::del;
#endif

// Allow pasting things, even if one of the arguments is a macro itself
#define PASTE(A, B)              DOPASTE (A, B)
#define DOPASTE(A, B)            DODOPASTE (A, B)
#define DODOPASTE(A, B)          A ## B

#define PASTE3(A, B, C)          PASTE (PASTE (A, B), C)
#define PASTE4(A, B, C, D)       PASTE (PASTE3 (A, B, C), D)
#define PASTE5(A, B, C, D, E)    PASTE (PASTE4 (A, B, C, D), E)
#define PASTE6(A, B, C, D, E, F) PASTE (PASTE5 (A, B, C, D, E), F)

namespace impl
{
  template<bool>
  struct static_assert;

  template<>
  struct static_assert<true>
  {
  };
}

#define static_assert(cond) ::impl::static_assert<(cond)> PASTE (static_assert_, __LINE__)

#endif
Revision:	1.5
Committed:	Wed Sep 5 11:23:13 2007 UTC (19 years, 2 months ago) by pippijn
Content type:	text/plain
Branch:	MAIN
Changes since 1.4:	+7 -17 lines
Log Message:	removed GPLed code and put license back to BSD
#	User	Rev	Content
1	pippijn	1.2	/*
2			* Copyright © 2007 Pippijn van Steenhoven / The Ermyth Team
3	pippijn	1.5	* Rights to this code are as documented in doc/pod/license.pod.
4	pippijn	1.2	*
5			* Various utility functions.
6			*
7	pippijn	1.5	* $Id: util.h,v 1.4 2007-08-30 19:56:20 pippijn Exp $
8	pippijn	1.2	*/
9
10	pippijn	1.1	#ifndef UTIL_H
11			#define UTIL_H
12
13			#include <climits>
14			#include <cstddef>
15			#include <vector>
16
17	pippijn	1.3	#include <ermyth/exception.h>
18	pippijn	1.1
19			/**
20			* Mostly the same as std::vector, but erase can reorder
21			* the elements, making insert/remove O(1) instead of O(n).
22			*
23			* NOTE: only some forms of erase are available
24			* (Taken from Crossfire TRT http://cf.schmorp.de/)
25			*/
26			template<typename T, typename Alloc = std::allocator<T> >
27			struct unordered_vector : std::vector<T, Alloc>
28			{
29			typedef typename unordered_vector::iterator iterator;
30
31			void erase (unsigned pos)
32			{
33			if (pos < this->size () - 1)
34			(this)[pos] = (this)[this->size () - 1];
35
36			this->pop_back ();
37			}
38
39			void erase (iterator pos)
40			{
41			erase ((unsigned)(pos - this->begin ()));
42			}
43
44			void insert (T const &val)
45			{
46			push_back (val);
47			}
48			};
49
50			/**
51			* The following templates find a sufficiently large integer type to contain
52			* the given number of bits.
53			*
54			* Usage:
55			*
56			* unsigned_type<16>::type a; // 16-bit unsigned if available (probably unsigned short)
57			* signed_type<8>::type a; // 8-bit signed if available (probably char)
58			*/
59
60			// Empty class if everything failed
61			struct empty_base
62			{
63			};
64
65			// To allow inheritance from this and get the integer type out
66			template<typename T>
67			struct identity
68			{
69			typedef T type;
70			};
71
72			/**
73			* The following two templates are a compile-time if-statement.
74			*/
75			template<bool Cond, class Then, class Else>
76			struct If
77			{
78			typedef Then ret;
79			};
80
81			template<class Then, class Else>
82			struct If<false, Then, Else>
83			{
84			typedef Else ret;
85			};
86
87			// Looks whether the desired type exists
88			template<typename T, std::size_t bits, typename Else>
89			struct type_if_size
90			: If<sizeof (T) * CHAR_BIT >= bits, identity<T>, Else>::ret
91			{
92			};
93
94			template<std::size_t bits>
95			struct unsigned_type
96			: type_if_size<unsigned char, bits,
97			type_if_size<unsigned short, bits,
98			type_if_size<unsigned int, bits,
99			type_if_size<unsigned long, bits,
100			empty_base // No such type
101			>
102			>
103			>
104			>
105			{
106			};
107
108			template<std::size_t bits>
109			struct signed_type
110			: type_if_size<signed char, bits
111			, type_if_size<signed short, bits
112			, type_if_size<signed int, bits
113			, type_if_size<signed long, bits
114			, empty_base // No such type
115			>
116			>
117			>
118			>
119			{
120			};
121
122	pippijn	1.3	// This is a vector that stores each element's index in the object.
123			// This only works for pointers to objects.
124	pippijn	1.1	template<class T, int T::index = &T::index, class Alloc = std::allocator<T > >
125			struct indexing_vector : std::vector<T *, Alloc>
126			{
127			typedef typename indexing_vector::size_type size_type;
128			typedef typename indexing_vector::iterator iterator;
129
130	pippijn	1.3	iterator find (const T *obj)
131			{
132			return obj->*index
133			? this->begin () + obj->*index - 1
134			: this->end ();
135			}
136
137	pippijn	1.1	void erase (T *obj)
138			{
139	pippijn	1.3	unsigned int pos = obj->*index;
140	pippijn	1.1	obj->*index = 0;
141
142	pippijn	1.3	if (pos < this->size ())
143	pippijn	1.1	{
144	pippijn	1.3	(this)[pos - 1] = (this)[this->size () - 1];
145			(this)[pos - 1]->index = pos;
146	pippijn	1.1	}
147
148			this->pop_back ();
149			}
150
151			void insert (T *obj)
152			{
153			this->push_back (obj);
154			obj->*index = this->size ();
155			}
156			};
157
158			struct str_hash
159			{
160			std::size_t operator () (char const *s) const
161			{
162			unsigned long hash = 0;
163
164			// use the one-at-a-time hash function.
165			// see http://burtleburtle.net/bob/hash/doobs.html
166			while (*s)
167			{
168			hash += *s++;
169			hash += hash << 10;
170			hash ^= hash >> 6;
171			}
172
173			hash += hash << 3;
174			hash ^= hash >> 11;
175			hash += hash << 15;
176
177			return hash;
178			}
179			};
180
181			struct str_eq
182			{
183			bool operator () (char const * const s1, char const * const s2) const
184			{
185			if (s1 == NULL \|\| s2 == NULL)
186			throw nullpointer_exception ();
187			return !strcmp (s1, s2);
188			}
189			};
190
191			struct str_lt
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) < 0;
198			}
199			};
200
201	pippijn	1.3	E int irccasecmp (char const * const s1, char const * const s2);
202			E int ircncasecmp (char const * const s1, char const * const s2, int maxlen);
203
204			struct irccase_lt
205			{
206			bool operator () (char const * const s1, char const * const s2) const
207			{
208			if (s1 == NULL \|\| s2 == NULL)
209			throw nullpointer_exception ();
210			return irccasecmp (s1, s2) < 0;
211			}
212			};
213
214	pippijn	1.5	typedef double tstamp;
215
216			inline tstamp
217	pippijn	1.3	now ()
218			{
219			#ifdef HAVE_GETTIMEOFDAY
220			struct timeval tv;
221
222			gettimeofday (&tv, 0);
223	pippijn	1.5	return tstamp (tv.tv_sec) + tstamp (tv.tv_usec) * tstamp (1e-6);
224	pippijn	1.3	#else
225	pippijn	1.5	return tstamp (time (NULL));
226	pippijn	1.3	#endif
227			}
228
229	pippijn	1.4	#if 0
230			/**
231			* Comma delimited output to std::cout
232			*/
233
234			namespace impl
235			{
236			struct C
237			{
238			template<typename T>
239			C operator << (T const &t) const
240			{
241			std::cout << ", " << t;
242			return C();
243			}
244
245			C operator << (std::ostream &(* const f) (std::ostream &)) const
246			{
247			std::cout << f;
248			return C();
249			}
250
251			C operator << (std::ios_base &(* const f) (std::ios_base &)) const
252			{
253			std::cout << f;
254			return C();
255			}
256			};
257
258			enum Del
259			{
260			del
261			};
262
263			template<typename T>
264			C operator << (Del, T const &t)
265			{
266			std::cout << t;
267			return C();
268			}
269
270			inline Del
271			operator << (Del, std::ostream &(* const f) (std::ostream &))
272			{
273			std::cout << f;
274			return del;
275			}
276
277			inline Del
278			operator << (Del, std::ios_base &(* const f) (std::ios_base &))
279			{
280			std::cout << f;
281			return del;
282			}
283
284			// The <<'s taking std::ios_base&(std::ios_base&)'s are for things like std::hex.
285			// The <<'s taking std::ostream&(std::ostream&)'s are for things like std::endl.
286
287			inline Del
288			operator << (std::ostream &, Del)
289			{
290			return del;
291			}
292			// To allow: std::cout << del << 2 << 4
293			}
294
295			using impl::del;
296			#endif
297
298			// Allow pasting things, even if one of the arguments is a macro itself
299			#define PASTE(A, B) DOPASTE (A, B)
300			#define DOPASTE(A, B) DODOPASTE (A, B)
301			#define DODOPASTE(A, B) A ## B
302
303			#define PASTE3(A, B, C) PASTE (PASTE (A, B), C)
304			#define PASTE4(A, B, C, D) PASTE (PASTE3 (A, B, C), D)
305			#define PASTE5(A, B, C, D, E) PASTE (PASTE4 (A, B, C, D), E)
306			#define PASTE6(A, B, C, D, E, F) PASTE (PASTE5 (A, B, C, D, E), F)
307
308			namespace impl
309			{
310			template<bool>
311			struct static_assert;
312
313			template<>
314			struct static_assert<true>
315			{
316			};
317			}
318
319			#define static_assert(cond) ::impl::static_assert<(cond)> PASTE (static_assert_, __LINE__)
320	pippijn	1.3
321	pippijn	1.1	#endif