include/common/util.h

/**
 * util.h: Various utility functions.
 *
 * Copyright © 2007 Pippijn van Steenhoven / The Ermyth Team
 * Rights to this code are as documented in doc/pod/gplicense.pod.
 *
 * $Id: util.h,v 1.7 2007-09-16 18:54:42 pippijn Exp $
 */

#ifndef UTIL_H
#define UTIL_H

#include <sysconf.h>

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

#include <ermyth/exception.h>

#include <sys/time.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, unsigned 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 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__)

E int itoa (uint32_t n, char *buf, int buflen);
E int itoa (uint64_t n, char *buf, int buflen);

inline int
itoa (int32_t n, char *buf, int buflen)
{
  *buf = '-';
  buf += (n < 0);
  uint32_t u = n < 0 ? -n : n;
  return itoa (u, buf, buflen - 1);
}

inline int
itoa (int64_t n, char *buf, int buflen)
{
  *buf = '-';
  buf += (n < 0);
  uint64_t u = n < 0 ? -n : n;
  return itoa (u, buf, buflen - 1);
}

template<typename IntType, int N>
inline int
itoa (IntType n, char (&buf)[N])
{
  return itoa (n, buf, N);
}

#endif
Revision:	1.8
Committed:	Sat Sep 22 14:27:26 2007 UTC (19 years, 1 month ago) by pippijn
Content type:	text/plain
Branch:	MAIN
CVS Tags:	HEAD
Changes since 1.7:	+1 -1 lines
State:	*FILE REMOVED*
Log Message:	split up ermyth into ermyth-modules, libermyth (currently just ermyth-util) and ermyth-core
#	Content
1	/**
2	* util.h: Various utility functions.
3	*
4	* Copyright © 2007 Pippijn van Steenhoven / The Ermyth Team
5	* Rights to this code are as documented in doc/pod/gplicense.pod.
6	*
7	* $Id: util.h,v 1.7 2007-09-16 18:54:42 pippijn Exp $
8	*/
9
10	#ifndef UTIL_H
11	#define UTIL_H
12
13	#include <sysconf.h>
14
15	#include <climits>
16	#include <cstddef>
17	#include <vector>
18
19	#include <ermyth/exception.h>
20
21	#include <sys/time.h>
22
23	/**
24	* Mostly the same as std::vector, but erase can reorder
25	* the elements, making insert/remove O(1) instead of O(n).
26	*
27	* NOTE: only some forms of erase are available
28	* (Taken from Crossfire TRT http://cf.schmorp.de/)
29	*/
30	template<typename T, typename Alloc = std::allocator<T> >
31	struct unordered_vector : std::vector<T, Alloc>
32	{
33	typedef typename unordered_vector::iterator iterator;
34
35	void erase (unsigned pos)
36	{
37	if (pos < this->size () - 1)
38	(this)[pos] = (this)[this->size () - 1];
39
40	this->pop_back ();
41	}
42
43	void erase (iterator pos)
44	{
45	erase ((unsigned)(pos - this->begin ()));
46	}
47
48	void insert (T const &val)
49	{
50	push_back (val);
51	}
52	};
53
54	/**
55	* The following templates find a sufficiently large integer type to contain
56	* the given number of bits.
57	*
58	* Usage:
59	*
60	* unsigned_type<16>::type a; // 16-bit unsigned if available (probably unsigned short)
61	* signed_type<8>::type a; // 8-bit signed if available (probably char)
62	*/
63
64	// Empty class if everything failed
65	struct empty_base
66	{
67	};
68
69	// To allow inheritance from this and get the integer type out
70	template<typename T>
71	struct identity
72	{
73	typedef T type;
74	};
75
76	/**
77	* The following two templates are a compile-time if-statement.
78	*/
79	template<bool Cond, class Then, class Else>
80	struct If
81	{
82	typedef Then ret;
83	};
84
85	template<class Then, class Else>
86	struct If<false, Then, Else>
87	{
88	typedef Else ret;
89	};
90
91	// Looks whether the desired type exists
92	template<typename T, std::size_t bits, typename Else>
93	struct type_if_size
94	: If<sizeof (T) * CHAR_BIT >= bits, identity<T>, Else>::ret
95	{
96	};
97
98	template<std::size_t bits>
99	struct unsigned_type
100	: type_if_size<unsigned char, bits,
101	type_if_size<unsigned short, bits,
102	type_if_size<unsigned int, bits,
103	type_if_size<unsigned long, bits,
104	empty_base // No such type
105	>
106	>
107	>
108	>
109	{
110	};
111
112	template<std::size_t bits>
113	struct signed_type
114	: type_if_size<signed char, bits
115	, type_if_size<signed short, bits
116	, type_if_size<signed int, bits
117	, type_if_size<signed long, bits
118	, empty_base // No such type
119	>
120	>
121	>
122	>
123	{
124	};
125
126	// This is a vector that stores each element's index in the object.
127	// This only works for pointers to objects.
128	template<class T, unsigned T::index = &T::index, class Alloc = std::allocator<T > >
129	struct indexing_vector : std::vector<T *, Alloc>
130	{
131	typedef typename indexing_vector::size_type size_type;
132	typedef typename indexing_vector::iterator iterator;
133
134	iterator find (const T *obj)
135	{
136	return obj->*index
137	? this->begin () + obj->*index - 1
138	: this->end ();
139	}
140
141	void erase (T *obj)
142	{
143	unsigned pos = obj->*index;
144	obj->*index = 0;
145
146	if (pos < this->size ())
147	{
148	(this)[pos - 1] = (this)[this->size () - 1];
149	(this)[pos - 1]->index = pos;
150	}
151
152	this->pop_back ();
153	}
154
155	void insert (T *obj)
156	{
157	this->push_back (obj);
158	obj->*index = this->size ();
159	}
160	};
161
162	struct str_hash
163	{
164	std::size_t operator () (char const *s) const
165	{
166	unsigned long hash = 0;
167
168	// use the one-at-a-time hash function.
169	// see http://burtleburtle.net/bob/hash/doobs.html
170	while (*s)
171	{
172	hash += *s++;
173	hash += hash << 10;
174	hash ^= hash >> 6;
175	}
176
177	hash += hash << 3;
178	hash ^= hash >> 11;
179	hash += hash << 15;
180
181	return hash;
182	}
183	};
184
185	struct str_eq
186	{
187	bool operator () (char const * const s1, char const * const s2) const
188	{
189	if (s1 == NULL \|\| s2 == NULL)
190	throw nullpointer_exception ();
191	return !strcmp (s1, s2);
192	}
193	};
194
195	struct str_lt
196	{
197	bool operator () (char const * const s1, char const * const s2) const
198	{
199	if (s1 == NULL \|\| s2 == NULL)
200	throw nullpointer_exception ();
201	return strcmp (s1, s2) < 0;
202	}
203	};
204
205	E int irccasecmp (char const * const s1, char const * const s2);
206	E int ircncasecmp (char const * const s1, char const * const s2, int maxlen);
207
208	struct irccase_lt
209	{
210	bool operator () (char const * const s1, char const * const s2) const
211	{
212	if (s1 == NULL \|\| s2 == NULL)
213	throw nullpointer_exception ();
214	return irccasecmp (s1, s2) < 0;
215	}
216	};
217
218	typedef double tstamp;
219
220	inline tstamp
221	now ()
222	{
223	#ifdef HAVE_GETTIMEOFDAY
224	struct timeval tv;
225
226	gettimeofday (&tv, 0);
227	return tstamp (tv.tv_sec) + tstamp (tv.tv_usec) * tstamp (1e-6);
228	#else
229	return tstamp (time (NULL));
230	#endif
231	}
232
233	#if 0
234	/**
235	* Comma delimited output to std::cout
236	*/
237
238	namespace impl
239	{
240	struct C
241	{
242	template<typename T>
243	C operator << (T const &t) const
244	{
245	std::cout << ", " << t;
246	return C();
247	}
248
249	C operator << (std::ostream &(* const f) (std::ostream &)) const
250	{
251	std::cout << f;
252	return C();
253	}
254
255	C operator << (std::ios_base &(* const f) (std::ios_base &)) const
256	{
257	std::cout << f;
258	return C();
259	}
260	};
261
262	enum Del
263	{
264	del
265	};
266
267	template<typename T>
268	C operator << (Del, T const &t)
269	{
270	std::cout << t;
271	return C();
272	}
273
274	inline Del
275	operator << (Del, std::ostream &(* const f) (std::ostream &))
276	{
277	std::cout << f;
278	return del;
279	}
280
281	inline Del
282	operator << (Del, std::ios_base &(* const f) (std::ios_base &))
283	{
284	std::cout << f;
285	return del;
286	}
287
288	// The <<'s taking std::ios_base&(std::ios_base&)'s are for things like std::hex.
289	// The <<'s taking std::ostream&(std::ostream&)'s are for things like std::endl.
290
291	inline Del
292	operator << (std::ostream &, Del)
293	{
294	return del;
295	}
296	// To allow: std::cout << del << 2 << 4
297	}
298
299	using impl::del;
300	#endif
301
302	// Allow pasting things, even if one of the arguments is a macro itself
303	#define PASTE(A, B) DOPASTE (A, B)
304	#define DOPASTE(A, B) DODOPASTE (A, B)
305	#define DODOPASTE(A, B) A ## B
306
307	#define PASTE3(A, B, C) PASTE (PASTE (A, B), C)
308	#define PASTE4(A, B, C, D) PASTE (PASTE3 (A, B, C), D)
309	#define PASTE5(A, B, C, D, E) PASTE (PASTE4 (A, B, C, D), E)
310	#define PASTE6(A, B, C, D, E, F) PASTE (PASTE5 (A, B, C, D, E), F)
311
312	namespace impl
313	{
314	template<bool>
315	struct static_assert;
316
317	template<>
318	struct static_assert<true>
319	{
320	};
321	}
322
323	#define static_assert(cond) ::impl::static_assert<(cond)> PASTE (static_assert_, __LINE__)
324
325	E int itoa (uint32_t n, char *buf, int buflen);
326	E int itoa (uint64_t n, char *buf, int buflen);
327
328	inline int
329	itoa (int32_t n, char *buf, int buflen)
330	{
331	*buf = '-';
332	buf += (n < 0);
333	uint32_t u = n < 0 ? -n : n;
334	return itoa (u, buf, buflen - 1);
335	}
336
337	inline int
338	itoa (int64_t n, char *buf, int buflen)
339	{
340	*buf = '-';
341	buf += (n < 0);
342	uint64_t u = n < 0 ? -n : n;
343	return itoa (u, buf, buflen - 1);
344	}
345
346	template<typename IntType, int N>
347	inline int
348	itoa (IntType n, char (&buf)[N])
349	{
350	return itoa (n, buf, N);
351	}
352
353	#endif