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 "util.h"

extern size_t shstr_alloc;

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

// 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 const char *null;

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

  shstr_cmp (const shstr &sh)
  : s (sh.s)
  {
  }

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

  shstr_cmp operator =(const shstr_cmp sh) { s = sh.s; return *this; }
  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;
}

extern const shstr shstr_null;

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

#endif

Revision:	1.24
Committed:	Wed Dec 31 17:35:37 2008 UTC (15 years, 4 months ago) by root
Content type:	text/plain
Branch:	MAIN
Changes since 1.23:	+105 -70 lines
Log Message:	refactoring of shstr classe,s new shstr_tmp, lots of minor rewriting
#	User	Rev	Content
1	root	1.16	/*
2	root	1.20	* This file is part of Deliantra, the Roguelike Realtime MMORPG.
3	root	1.16	*
4	root	1.22	* Copyright (©) 2005,2006,2007,2008 Marc Alexander Lehmann / Robin Redeker / the Deliantra team
5	root	1.16	*
6	root	1.20	* Deliantra is free software: you can redistribute it and/or modify
7	root	1.17	* 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	root	1.16	*
11	root	1.17	* 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	root	1.16	*
16	root	1.17	* 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	root	1.16	*
19	root	1.20	* The authors can be reached via e-mail to <support@deliantra.net>
20	root	1.16	*/
21
22	root	1.2	#ifndef SHSTR_H__
23			#define SHSTR_H__
24
25	root	1.24	#include <cstring>
26	root	1.13	#include <sstream>
27
28	root	1.8	#include "util.h"
29
30	root	1.19	extern size_t shstr_alloc;
31
32	root	1.8	extern int buf_overflow (const char buf1, const char buf2, int bufsize);
33	root	1.5
34	root	1.24	// this class is a non-refcounted shared string
35			// it cannot be used to create or store shared strings, but
36			// it can be used to apss shared strings around, i.e. as function arguments
37			// or return values. their lifetime must not span a gc () call, i.e.
38			// they are only valid as temporary values within the same server tick.
39			struct shstr_tmp
40	root	1.5	{
41	root	1.8	static const char *null;
42
43	root	1.5	const char *s;
44	root	1.4
45	root	1.24	static unsigned int &length (const char *s)
46	root	1.5	{
47	root	1.24	return ((unsigned int )s - 2);
48	root	1.5	}
49
50	root	1.24	int length () const
51	root	1.7	{
52	root	1.24	return length (s);
53	root	1.7	}
54
55	root	1.24	// returns whether this shared string begins with the given prefix,
56			// used mainly for searches when users give only the start of a name.
57			bool starts_with (const char *prefix) const
58	root	1.7	{
59	root	1.24	int plen = strlen (prefix);
60
61			return length () >= plen && !strncasecmp (s, prefix, plen);
62	root	1.7	}
63
64	root	1.24	bool contains (const char *substring) const
65	root	1.7	{
66	root	1.24	return strstr (s, substring);
67	root	1.7	}
68
69	root	1.24	shstr_tmp ()
70			: s (null)
71			{
72			}
73
74			shstr_tmp (const shstr_tmp &sh)
75			: s (sh.s)
76	root	1.15	{
77			}
78
79	root	1.24	shstr_tmp operator =(const shstr_tmp &sh)
80			{
81			s = sh.s;
82	root	1.5
83	root	1.24	return *this;
84			}
85	root	1.5
86	root	1.6	// this is used for informational messages and the like
87	root	1.8	const char *operator &() const { return s; }
88	root	1.5
89	root	1.8	operator const char *() const { return s == null ? 0 : s; }
90	root	1.24	};
91
92			inline bool operator ==(const shstr_tmp &a, const shstr_tmp &b)
93			{
94			return a.s == b.s;
95			}
96
97			inline bool operator !=(const shstr_tmp &a, const shstr_tmp &b)
98			{
99			return a.s != b.s;
100			}
101
102			inline int strlen (const shstr_tmp &sh)
103			{
104			return sh.length ();
105			}
106
107			// undefined external reference to catch people using strcmp when they shouldn't
108			int strcmp (const shstr_tmp &a, const shstr_tmp &b);
109
110			static std::ostream &operator <<(std::ostream &o, shstr_tmp sh)
111			{
112			o.write (sh.s, sh.length ());
113
114			return o;
115			}
116
117			struct shstr : shstr_tmp
118			{
119			static unsigned int &refcnt (const char *s)
120			{
121			return ((unsigned int )s - 1);
122			}
123
124			unsigned int &refcnt () const
125			{
126			return refcnt (s);
127			}
128	root	1.5
129			shstr ()
130			{
131			}
132
133	root	1.24	static const char find (const char s);
134			static const char intern (const char s);
135
136			static void gc (); // garbage collect a few strings
137
138	root	1.6	shstr (const shstr &sh)
139	root	1.24	: shstr_tmp (sh)
140			{
141			++refcnt ();
142			}
143
144			shstr (const shstr_tmp &sh)
145			: shstr_tmp (sh)
146	root	1.5	{
147	root	1.8	++refcnt ();
148	root	1.5	}
149
150	root	1.24	explicit shstr (const char *str)
151	root	1.5	{
152	root	1.24	s = is_constant (str) && !str ? null : intern (str);
153	root	1.5	}
154
155			~shstr ()
156			{
157	root	1.8	--refcnt ();
158	root	1.5	}
159
160	root	1.24	using shstr_tmp::operator &;
161			using shstr_tmp::operator const char *;
162
163			// (note: not the copy constructor)
164			shstr &operator =(const shstr_tmp &sh)
165	root	1.5	{
166	root	1.8	--refcnt ();
167	root	1.5	s = sh.s;
168	root	1.8	++refcnt ();
169	root	1.5
170			return *this;
171			}
172
173	root	1.24	// here it comes
174			shstr &operator =(const shstr &sh)
175			{
176			return (*this) = (shstr_tmp)sh;
177			}
178
179			// shstr_tmp doesn't have this one
180			shstr &operator =(const char *str)
181	root	1.5	{
182	root	1.8	--refcnt ();
183	root	1.24	s = is_constant (str) && !str ? null : intern (str);
184	root	1.1
185	root	1.5	return *this;
186			}
187			};
188	root	1.1
189	root	1.24	// only good for mass comparisons to shstr objects, or very
190			// temporary passing, basically a non-refcounted shstr
191	root	1.10	struct shstr_cmp
192			{
193			const char *s;
194
195	root	1.24	explicit shstr_cmp (const char *str)
196			: s (shstr::find (str))
197	root	1.10	{
198			}
199
200	root	1.11	shstr_cmp (const shstr_cmp &sh)
201			: s (sh.s)
202			{
203			}
204
205	root	1.23	shstr_cmp (const shstr &sh)
206			: s (sh.s)
207			{
208			}
209
210			// this is used for informational messages and the like
211			const char *operator &() const { return s; }
212
213	root	1.24	shstr_cmp operator =(const shstr_cmp sh) { s = sh.s; return *this; }
214	root	1.10	operator const char *() const { return s; }
215			};
216
217	root	1.24	inline bool operator ==(const shstr_cmp &a, const shstr_tmp &b)
218	root	1.5	{
219			return a.s == b.s;
220			}
221	root	1.4
222	root	1.24	inline bool operator ==(const shstr_tmp &a, const shstr_cmp &b)
223	root	1.4	{
224	root	1.24	return a.s == b.s;
225	root	1.5	}
226	root	1.4
227	root	1.21	extern const shstr shstr_null;
228
229	root	1.18	#define def(str) extern const shstr shstr_ ## str;
230			# include "shstrinc.h"
231			#undef def
232	root	1.9
233	root	1.2	#endif
234