server/include/shstr.h

/*
 * This file is part of Deliantra, the Roguelike Realtime MMORPG.
 * 
 * Copyright (©) 2005,2006,2007,2008 Marc Alexander Lehmann / Robin Redeker / the Deliantra team
 * 
 * Deliantra is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 * 
 * The authors can be reached via e-mail to <support@deliantra.net>
 */

#ifndef SHSTR_H__
#define SHSTR_H__

#include <cstring>
#include <sstream>

#include "traits.h"

extern size_t shstr_alloc;

extern int buf_overflow (const char *buf1, const char *buf2, int bufsize);

template<int size>
struct shstr_vec
{
  uint32_t len;
  uint32_t refcnt;
  char string[size];
};

// this class is a non-refcounted shared string
// it cannot be used to create or store shared strings, but
// it can be used to apss shared strings around, i.e. as function arguments
// or return values. their lifetime must not span a gc () call, i.e.
// they are only valid as temporary values within the same server tick.
struct shstr_tmp
{
  static shstr_vec<sizeof ("(null)")> nullvec;
  static const char *null () { return nullvec.string; } // this is the null pointer value

  const char *s;

  static unsigned int &length (const char *s)
  {
    return *((unsigned int *)s - 2);
  }

  int length () const
  {
    return length (s);
  }

  // returns whether this shared string begins with the given prefix,
  // used mainly for searches when users give only the start of a name.
  bool starts_with (const char *prefix) const
  {
    int plen = strlen (prefix);

    return length () >= plen && !strncasecmp (s, prefix, plen);
  }

  bool contains (const char *substring) const
  {
    return strstr (s, substring);
  }

  shstr_tmp ()
  : s (null ())
  {
  }

  shstr_tmp (const shstr_tmp &sh)
  : s (sh.s)
  {
  }

  shstr_tmp operator =(const shstr_tmp &sh)
  {
    s = sh.s;

    return *this;
  }

  // this is used for informational messages and the like
  const char *operator &() const { return s; }

  operator const char *() const { return s == null () ? 0 : s; }
};

inline bool operator ==(const shstr_tmp &a, const shstr_tmp &b)
{
  return a.s == b.s;
}

inline bool operator !=(const shstr_tmp &a, const shstr_tmp &b)
{
  return a.s != b.s;
}

inline int strlen (const shstr_tmp &sh)
{
  return sh.length ();
}

// undefined external reference to catch people using strcmp when they shouldn't
int strcmp (const shstr_tmp &a, const shstr_tmp &b);

static std::ostream &operator <<(std::ostream &o, shstr_tmp sh)
{
  o.write (sh.s, sh.length ());

  return o;
}

struct shstr : shstr_tmp
{
  static unsigned int &refcnt (const char *s)
  {
    return *((unsigned int *)s - 1);
  }

  unsigned int &refcnt () const
  {
    return refcnt (s);
  }

  shstr ()
  {
  }

  static const char *find (const char *s);
  static const char *intern (const char *s);

  static void gc (); // garbage collect a few strings

  shstr (const shstr &sh)
  : shstr_tmp (sh)
  {
    ++refcnt ();
  }

  shstr (const shstr_tmp &sh)
  : shstr_tmp (sh)
  {
    ++refcnt ();
  }

  explicit shstr (const char *str)
  {
    s = is_constant (str) && !str ? null () : intern (str);
  }

  ~shstr ()
  {
    --refcnt ();
  }

  using shstr_tmp::operator &;
  using shstr_tmp::operator const char *;

  // (note: not the copy constructor)
  shstr &operator =(const shstr_tmp &sh)
  {
    --refcnt ();
    s = sh.s;
    ++refcnt ();

    return *this;
  }

  // here it comes
  shstr &operator =(const shstr &sh)
  {
    return (*this) = (shstr_tmp)sh;
  }

  // shstr_tmp doesn't have this one
  shstr &operator =(const char *str)
  {
    --refcnt ();
    s = is_constant (str) && !str ? null () : intern (str);

    return *this;
  }
};

// only good for mass comparisons to shstr objects, or very
// temporary passing, basically a non-refcounted shstr
struct shstr_cmp
{
  const char *s;

  explicit shstr_cmp (const char *str)
  : s (shstr::find (str))
  {
  }

  shstr_cmp (shstr_tmp sh)
  : s (sh.s)
  {
  }

  // this is used for informational messages and the like
  const char *operator &() const { return s; }

  operator const char *() const { return s; }
};

inline bool operator ==(const shstr_cmp &a, const shstr_tmp &b)
{
  return a.s == b.s;
}

inline bool operator ==(const shstr_tmp &a, const shstr_cmp &b)
{
  return a.s == b.s;
}

#define def(str) extern const shstr shstr_ ## str;
# include "shstrinc.h"
#undef def

#endif

Revision:	1.25
Committed:	Wed Dec 31 18:07:41 2008 UTC (15 years, 4 months ago) by root
Content type:	text/plain
Branch:	MAIN
Changes since 1.24:	+16 -15 lines
Log Message:	further optimisations
#	Content
1	/*
2	* This file is part of Deliantra, the Roguelike Realtime MMORPG.
3	*
4	* Copyright (©) 2005,2006,2007,2008 Marc Alexander Lehmann / Robin Redeker / the Deliantra team
5	*
6	* Deliantra is free software: you can redistribute it and/or modify
7	* it under the terms of the GNU General Public License as published by
8	* the Free Software Foundation, either version 3 of the License, or
9	* (at your option) any later version.
10	*
11	* This program is distributed in the hope that it will be useful,
12	* but WITHOUT ANY WARRANTY; without even the implied warranty of
13	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14	* GNU General Public License for more details.
15	*
16	* You should have received a copy of the GNU General Public License
17	* along with this program. If not, see <http://www.gnu.org/licenses/>.
18	*
19	* The authors can be reached via e-mail to <support@deliantra.net>
20	*/
21
22	#ifndef SHSTR_H__
23	#define SHSTR_H__
24
25	#include <cstring>
26	#include <sstream>
27
28	#include "traits.h"
29
30	extern size_t shstr_alloc;
31
32	extern int buf_overflow (const char buf1, const char buf2, int bufsize);
33
34	template<int size>
35	struct shstr_vec
36	{
37	uint32_t len;
38	uint32_t refcnt;
39	char string[size];
40	};
41
42	// this class is a non-refcounted shared string
43	// it cannot be used to create or store shared strings, but
44	// it can be used to apss shared strings around, i.e. as function arguments
45	// or return values. their lifetime must not span a gc () call, i.e.
46	// they are only valid as temporary values within the same server tick.
47	struct shstr_tmp
48	{
49	static shstr_vec<sizeof ("(null)")> nullvec;
50	static const char *null () { return nullvec.string; } // this is the null pointer value
51
52	const char *s;
53
54	static unsigned int &length (const char *s)
55	{
56	return ((unsigned int )s - 2);
57	}
58
59	int length () const
60	{
61	return length (s);
62	}
63
64	// returns whether this shared string begins with the given prefix,
65	// used mainly for searches when users give only the start of a name.
66	bool starts_with (const char *prefix) const
67	{
68	int plen = strlen (prefix);
69
70	return length () >= plen && !strncasecmp (s, prefix, plen);
71	}
72
73	bool contains (const char *substring) const
74	{
75	return strstr (s, substring);
76	}
77
78	shstr_tmp ()
79	: s (null ())
80	{
81	}
82
83	shstr_tmp (const shstr_tmp &sh)
84	: s (sh.s)
85	{
86	}
87
88	shstr_tmp operator =(const shstr_tmp &sh)
89	{
90	s = sh.s;
91
92	return *this;
93	}
94
95	// this is used for informational messages and the like
96	const char *operator &() const { return s; }
97
98	operator const char *() const { return s == null () ? 0 : s; }
99	};
100
101	inline bool operator ==(const shstr_tmp &a, const shstr_tmp &b)
102	{
103	return a.s == b.s;
104	}
105
106	inline bool operator !=(const shstr_tmp &a, const shstr_tmp &b)
107	{
108	return a.s != b.s;
109	}
110
111	inline int strlen (const shstr_tmp &sh)
112	{
113	return sh.length ();
114	}
115
116	// undefined external reference to catch people using strcmp when they shouldn't
117	int strcmp (const shstr_tmp &a, const shstr_tmp &b);
118
119	static std::ostream &operator <<(std::ostream &o, shstr_tmp sh)
120	{
121	o.write (sh.s, sh.length ());
122
123	return o;
124	}
125
126	struct shstr : shstr_tmp
127	{
128	static unsigned int &refcnt (const char *s)
129	{
130	return ((unsigned int )s - 1);
131	}
132
133	unsigned int &refcnt () const
134	{
135	return refcnt (s);
136	}
137
138	shstr ()
139	{
140	}
141
142	static const char find (const char s);
143	static const char intern (const char s);
144
145	static void gc (); // garbage collect a few strings
146
147	shstr (const shstr &sh)
148	: shstr_tmp (sh)
149	{
150	++refcnt ();
151	}
152
153	shstr (const shstr_tmp &sh)
154	: shstr_tmp (sh)
155	{
156	++refcnt ();
157	}
158
159	explicit shstr (const char *str)
160	{
161	s = is_constant (str) && !str ? null () : intern (str);
162	}
163
164	~shstr ()
165	{
166	--refcnt ();
167	}
168
169	using shstr_tmp::operator &;
170	using shstr_tmp::operator const char *;
171
172	// (note: not the copy constructor)
173	shstr &operator =(const shstr_tmp &sh)
174	{
175	--refcnt ();
176	s = sh.s;
177	++refcnt ();
178
179	return *this;
180	}
181
182	// here it comes
183	shstr &operator =(const shstr &sh)
184	{
185	return (*this) = (shstr_tmp)sh;
186	}
187
188	// shstr_tmp doesn't have this one
189	shstr &operator =(const char *str)
190	{
191	--refcnt ();
192	s = is_constant (str) && !str ? null () : intern (str);
193
194	return *this;
195	}
196	};
197
198	// only good for mass comparisons to shstr objects, or very
199	// temporary passing, basically a non-refcounted shstr
200	struct shstr_cmp
201	{
202	const char *s;
203
204	explicit shstr_cmp (const char *str)
205	: s (shstr::find (str))
206	{
207	}
208
209	shstr_cmp (shstr_tmp sh)
210	: s (sh.s)
211	{
212	}
213
214	// this is used for informational messages and the like
215	const char *operator &() const { return s; }
216
217	operator const char *() const { return s; }
218	};
219
220	inline bool operator ==(const shstr_cmp &a, const shstr_tmp &b)
221	{
222	return a.s == b.s;
223	}
224
225	inline bool operator ==(const shstr_tmp &a, const shstr_cmp &b)
226	{
227	return a.s == b.s;
228	}
229
230	#define def(str) extern const shstr shstr_ ## str;
231	# include "shstrinc.h"
232	#undef def
233
234	#endif
235