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Comparing deliantra/server/include/shstr.h (file contents):
Revision 1.1 by root, Fri Feb 3 07:12:50 2006 UTC vs.
Revision 1.35 by root, Fri Nov 6 13:45:28 2009 UTC

1/* The size of the shared strings hashtable. This must be smaller than 1/*
2 * 32767, but 947 ought to be plenty enough. 2 * This file is part of Deliantra, the Roguelike Realtime MMORPG.
3 *
4 * Copyright (©) 2005,2006,2007,2008,2009 Marc Alexander Lehmann / Robin Redeker / the Deliantra team
5 *
6 * Deliantra is free software: you can redistribute it and/or modify it under
7 * the terms of the Affero GNU General Public License as published by the
8 * Free Software Foundation, either version 3 of the License, or (at your
9 * 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 Affero GNU General Public License
17 * and the GNU General Public License along with this program. If not, see
18 * <http://www.gnu.org/licenses/>.
19 *
20 * The authors can be reached via e-mail to <support@deliantra.net>
3 */ 21 */
4#define TABLESIZE 4133
5 22
6/* This specifies how many characters the hashing routine should look at. 23#ifndef SHSTR_H__
7 * You may actually save CPU by increasing this number if the typical string 24#define SHSTR_H__
8 * is large. 25
9 */ 26#include <cstring>
10#ifndef MAXSTRING 27#include <sstream>
11#define MAXSTRING 20 28
29#include "traits.h"
30
31extern size_t shstr_alloc;
32
33extern int buf_overflow (const char *buf1, const char *buf2, int bufsize);
34
35template<int size>
36struct shstr_vec
37{
38 uint32_t len;
39 uint32_t refcnt;
40 char string[size];
41};
42
43// this class is a non-refcounted shared string
44// it cannot be used to create or store shared strings, but
45// it can be used to apss shared strings around, i.e. as function arguments
46// or return values. their lifetime must not span a gc () call, i.e.
47// they are only valid as temporary values within the same server tick.
48struct shstr_tmp
49{
50 static shstr_vec<sizeof ("(null)")> nullvec;
51 static const char *null () { return nullvec.string; } // this is the null pointer value
52
53 const char *s;
54
55 static unsigned int &length (const char *s)
56 {
57 return *((unsigned int *)s - 2);
58 }
59
60 int length () const
61 {
62 return length (s);
63 }
64
65 // returns whether this shared string begins with the given prefix,
66 // used mainly for searches when users give only the start of a name.
67 bool starts_with (const char *prefix) const
68 {
69 int plen = strlen (prefix);
70
71 return length () >= plen && !strncasecmp (s, prefix, plen);
72 }
73
74 // returns true if the substring is contained in the shstr
75 // if the shstr is 0, then this always returns false.
76 // the shstr is (theoretically) treated as a comma/colon/space etc. separated list.
77 bool contains (const char *substring) const
78 {
79 return s != null () && strstr (s, substring);
80 }
81
82 //TODO: case sensitive should be eradicated
83 bool eq_nc (const char *otherstring) const
84 {
85 return !strcasecmp (s, otherstring);
86 }
87
88 shstr_tmp ()
89 : s (null ())
90 {
91 }
92
93 shstr_tmp (const shstr_tmp &sh)
94 : s (sh.s)
95 {
96 }
97
98 shstr_tmp operator =(const shstr_tmp &sh)
99 {
100 s = sh.s;
101
102 return *this;
103 }
104
105 // this is used for informational messages and the like
106 const char *operator &() const { return s; }
107
108 operator const char *() const { return s == null () ? 0 : s; }
109
110protected:
111 // dummy is there so it isn't used as type converter accidentally
112 shstr_tmp (int dummy, const char *s)
113 : s(s)
114 {
115 }
116};
117
118inline bool operator ==(const shstr_tmp &a, const shstr_tmp &b)
119{
120 return a.s == b.s;
121}
122
123inline bool operator !=(const shstr_tmp &a, const shstr_tmp &b)
124{
125 return a.s != b.s;
126}
127
128inline int strlen (shstr_tmp sh)
129{
130 return sh.length ();
131}
132
133static inline std::ostream &operator <<(std::ostream &o, shstr_tmp sh)
134{
135 o.write (sh.s, sh.length ());
136
137 return o;
138}
139
140struct shstr : shstr_tmp
141{
142 static unsigned int &refcnt (const char *s)
143 {
144 return *((unsigned int *)s - 1);
145 }
146
147 unsigned int &refcnt () const
148 {
149 return refcnt (s);
150 }
151
152 shstr ()
153 {
154 }
155
156 static const char *find (const char *s);
157 static const char *intern (const char *s);
158
159 static void gc (); // garbage collect a few strings
160
161 shstr (const shstr &sh)
162 : shstr_tmp (sh)
163 {
164 ++refcnt ();
165 }
166
167 shstr (const shstr_tmp &sh)
168 : shstr_tmp (sh)
169 {
170 ++refcnt ();
171 }
172
173 explicit shstr (const char *str)
174 : shstr_tmp (0, is_constant (str) && !str ? null () : intern (str))
175 {
176 }
177
178 ~shstr ()
179 {
180 --refcnt ();
181 }
182
183 using shstr_tmp::operator &;
184 using shstr_tmp::operator const char *;
185
186 // (note: not the copy constructor)
187 shstr &operator =(const shstr_tmp &sh)
188 {
189 --refcnt ();
190 s = sh.s;
191 ++refcnt ();
192
193 return *this;
194 }
195
196 // here it comes
197 shstr &operator =(const shstr &sh)
198 {
199 return (*this) = (shstr_tmp)sh;
200 }
201
202 // shstr_tmp doesn't have this one
203 shstr &operator =(const char *str)
204 {
205 --refcnt ();
206 s = is_constant (str) && !str ? null () : intern (str);
207
208 return *this;
209 }
210};
211
212// only good for mass comparisons to shstr objects, or very
213// temporary passing, basically a non-refcounted shstr
214struct shstr_cmp
215{
216 const char *s;
217
218 // initialies to the non-matching string (as opposed to the null string)
219 shstr_cmp ()
220 {
221 s = 0;
222 }
223
224 shstr_cmp (const char *str)
225 : s (shstr::find (str))
226 {
227 }
228
229 shstr_cmp (shstr_tmp sh)
230 : s (sh.s)
231 {
232 }
233
234 // this is used for informational messages and the like
235 const char *operator &() const { return s; }
236
237 operator const char *() const { return s; }
238};
239
240inline bool operator ==(const shstr_cmp &a, const shstr_tmp &b)
241{
242 return a.s == b.s;
243}
244
245inline bool operator ==(const shstr_tmp &a, const shstr_cmp &b)
246{
247 return a.s == b.s;
248}
249
250#define def2(id,str) extern const shstr id;
251#define def(id) def2(shstr_ ## id, # id)
252# include "shstrinc.h"
253#undef def
254#undef def2
255
256// undefined external reference to catch people using str* functions when they shouldn't
257//template<class any> void strcmp (const shstr_tmp &a, any b);
258template<class any> void strstr (const shstr_tmp &a, any b);
259
12#endif 260#endif
13 261
14/* In the unlikely occurence that 16383 references to a string are too
15 * few, you can modify the below type to something bigger.
16 * (The top bit of "refcount" is used to signify that "u.array" points
17 * at the array entry.)
18 */
19#define REFCOUNT_TYPE int
20
21/* The offsetof macro is part of ANSI C, but many compilers lack it, for
22 * example "gcc -ansi"
23 */
24#if !defined (offsetof)
25#define offsetof(type, member) (int)&(((type *)0)->member)
26#endif
27
28/* SS(string) will return the address of the shared_string struct which
29 * contains "string".
30 */
31#define SS(x) ((shared_string *) ((x) - offsetof(shared_string, string)))
32
33#define SS_STATISTICS
34
35#define SS_DUMP_TABLE 1
36#define SS_DUMP_TOTALS 2
37
38#ifdef SS_STATISTICS
39static struct statistics {
40 int calls;
41 int hashed;
42 int strcmps;
43 int search;
44 int linked;
45} add_stats, add_ref_stats, free_stats, find_stats, hash_stats;
46#define GATHER(n) (++n)
47#else /* !SS_STATISTICS */
48#define GATHER(n)
49#endif /* SS_STATISTICS */
50
51#define TOPBIT ((unsigned REFCOUNT_TYPE) 1 << (sizeof(REFCOUNT_TYPE) * CHAR_BIT - 1))
52
53#define PADDING ((2 * sizeof(long) - sizeof(REFCOUNT_TYPE)) % sizeof(long)) + 1
54
55typedef struct _shared_string {
56 union {
57 struct _shared_string **array;
58 struct _shared_string *previous;
59 } u;
60 struct _shared_string *next;
61 /* The top bit of "refcount" is used to signify that "u.array" points
62 * at the array entry.
63 */
64 unsigned REFCOUNT_TYPE refcount;
65 /* Padding will be unused memory, since we can't know how large
66 * the padding when allocating memory. We assume here that
67 * sizeof(long) is a good boundary.
68 */
69 char string[PADDING];
70} shared_string;

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