include/common/util.h

/*
 * Copyright © 2007 Pippijn van Steenhoven / The Ermyth Team
 * Rights to this code are as documented in doc/pod/gplicense.pod.
 *
 * Various utility functions.
 *
 * $Id: util.h,v 1.2 2007-07-25 01:05:17 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.
//
// Based on the object_vector from Crossfire TRT
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 ();
  }

  iterator find (const T &obj)
  {
    return find (&obj);
  }

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

  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;
  }
};

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

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


#endif
Revision:	1.3
Committed:	Tue Aug 28 17:08:07 2007 UTC (19 years, 1 month ago) by pippijn
Content type:	text/plain
Branch:	MAIN
Changes since 1.2:	+54 -34 lines
Log Message:	- changed name - updated the example config to the new system - added more documentation - enhanced documentation generators - added a link to the pdf to the website - added an RSS feed generator - transitioned hooks to c++ callbacks - did various merges with upstream along the way - added const where appropriate - removed the old block allocator - fixed most memory leaks - transitioned some dictionaries to std::map - transitioned some lists to std::vector - made some free functions members where appropriate - renamed string to dynstr and added a static string ststr - use NOW instead of time (NULL) if possible - completely reworked database backends, crypto handlers and protocol handlers to use an object factory - removed the old module system. ermyth does not do any dynamic loading anymore - fixed most of the build system - reworked how protocol commands work
#	User	Rev	Content
1	pippijn	1.2	/*
2			* Copyright © 2007 Pippijn van Steenhoven / The Ermyth Team
3			* Rights to this code are as documented in doc/pod/gplicense.pod.
4			*
5			* Various utility functions.
6			*
7	pippijn	1.3	* $Id: util.h,v 1.2 2007-07-25 01:05:17 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			//
125			// Based on the object_vector from Crossfire TRT
126	pippijn	1.1	template<class T, int T::index = &T::index, class Alloc = std::allocator<T > >
127			struct indexing_vector : std::vector<T *, Alloc>
128			{
129			typedef typename indexing_vector::size_type size_type;
130			typedef typename indexing_vector::iterator iterator;
131
132	pippijn	1.3	iterator find (const T *obj)
133			{
134			return obj->*index
135			? this->begin () + obj->*index - 1
136			: this->end ();
137			}
138
139			iterator find (const T &obj)
140			{
141			return find (&obj);
142			}
143
144	pippijn	1.1	void erase (T *obj)
145			{
146	pippijn	1.3	unsigned int pos = obj->*index;
147	pippijn	1.1	obj->*index = 0;
148
149	pippijn	1.3	if (pos < this->size ())
150	pippijn	1.1	{
151	pippijn	1.3	(this)[pos - 1] = (this)[this->size () - 1];
152			(this)[pos - 1]->index = pos;
153	pippijn	1.1	}
154
155			this->pop_back ();
156			}
157
158	pippijn	1.3	void erase (T &obj)
159			{
160			erase (&obj);
161			}
162
163	pippijn	1.1	void insert (T *obj)
164			{
165			this->push_back (obj);
166			obj->*index = this->size ();
167			}
168			};
169
170			struct str_hash
171			{
172			std::size_t operator () (char const *s) const
173			{
174			unsigned long hash = 0;
175
176			// use the one-at-a-time hash function.
177			// see http://burtleburtle.net/bob/hash/doobs.html
178			while (*s)
179			{
180			hash += *s++;
181			hash += hash << 10;
182			hash ^= hash >> 6;
183			}
184
185			hash += hash << 3;
186			hash ^= hash >> 11;
187			hash += hash << 15;
188
189			return hash;
190			}
191			};
192
193			struct str_eq
194			{
195			bool operator () (char const * const s1, char const * const s2) const
196			{
197			if (s1 == NULL \|\| s2 == NULL)
198			throw nullpointer_exception ();
199			return !strcmp (s1, s2);
200			}
201			};
202
203			struct str_lt
204			{
205			bool operator () (char const * const s1, char const * const s2) const
206			{
207			if (s1 == NULL \|\| s2 == NULL)
208			throw nullpointer_exception ();
209			return strcmp (s1, s2) < 0;
210			}
211			};
212
213	pippijn	1.3	E int irccasecmp (char const * const s1, char const * const s2);
214			E int ircncasecmp (char const * const s1, char const * const s2, int maxlen);
215
216			struct irccase_lt
217			{
218			bool operator () (char const * const s1, char const * const s2) const
219			{
220			if (s1 == NULL \|\| s2 == NULL)
221			throw nullpointer_exception ();
222			return irccasecmp (s1, s2) < 0;
223			}
224			};
225
226			inline double
227			now ()
228			{
229			#ifdef HAVE_GETTIMEOFDAY
230			struct timeval tv;
231
232			gettimeofday (&tv, 0);
233			return double (tv.tv_sec) + double (tv.tv_usec) * double (1e-6);
234			#else
235			return double (time (NULL));
236			#endif
237			}
238
239
240	pippijn	1.1	#endif