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Comparing deliantra/server/include/shstr.h (file contents):
Revision 1.3 by root, Tue Aug 29 08:01:36 2006 UTC vs.
Revision 1.38 by root, Fri Mar 26 01:04:44 2010 UTC

1/*
2 * This file is part of Deliantra, the Roguelike Realtime MMORPG.
3 *
4 * Copyright (©) 2005,2006,2007,2008,2009,2010 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>
21 */
22
1#ifndef SHSTR_H__ 23#ifndef SHSTR_H__
2#define SHSTR_H__ 24#define SHSTR_H__
3 25
4/* The size of the shared strings hashtable. This must be smaller than 26#include <cstring>
5 * 32767, but 947 ought to be plenty enough. 27#include <sstream>
6 */
7#define TABLESIZE 4133
8 28
9/* This specifies how many characters the hashing routine should look at. 29#include "traits.h"
10 * You may actually save CPU by increasing this number if the typical string 30
11 * is large. 31extern size_t shstr_alloc;
12 */ 32
13#ifndef MAXSTRING 33extern int buf_overflow (const char *buf1, const char *buf2, int bufsize);
14#define MAXSTRING 20 34
35template<int size>
36struct shstr_vec
37{
38 uint32_t hash;
39 uint32_t len;
40 uint32_t refcnt;
41 // pointer points here
42 char string [size];
43};
44
45// this class is a non-refcounted shared string
46// it cannot be used to create or store shared strings, but
47// it can be used to pass shared strings around, i.e. as function arguments
48// or return values. their lifetime must not span a gc () call, i.e.
49// they are only valid as temporary values within the same server tick.
50struct shstr_tmp
51{
52 static shstr_vec<sizeof ("(null)")> nullvec;
53 static const char *null () { return nullvec.string; } // this is the null pointer value
54
55 const char *s;
56
57 static unsigned int &hash (const char *s)
58 {
59 return *((unsigned int *)s - 3);
60 }
61
62 int hash () const
63 {
64 return hash (s);
65 }
66
67 static unsigned int &length (const char *s)
68 {
69 return *((unsigned int *)s - 2);
70 }
71
72 int length () const
73 {
74 return length (s);
75 }
76
77 // returns whether this shared string begins with the given prefix,
78 // used mainly for searches when users give only the start of a name.
79 bool starts_with (const char *prefix) const
80 {
81 int plen = strlen (prefix);
82
83 return length () >= plen && !strncasecmp (s, prefix, plen);
84 }
85
86 // returns true if the substring is contained in the shstr
87 // if the shstr is 0, then this always returns false.
88 // the shstr is (theoretically) treated as a comma/colon/space etc. separated list.
89 bool contains (const char *substring) const
90 {
91 return s != null () && strstr (s, substring);
92 }
93
94 //TODO: case sensitive should be eradicated
95 bool eq_nc (const char *otherstring) const
96 {
97 return !strcasecmp (s, otherstring);
98 }
99
100 shstr_tmp ()
101 : s (null ())
102 {
103 }
104
105 shstr_tmp (const shstr_tmp &sh)
106 : s (sh.s)
107 {
108 }
109
110 shstr_tmp operator =(const shstr_tmp &sh)
111 {
112 s = sh.s;
113
114 return *this;
115 }
116
117 // this is used for informational messages and the like
118 const char *operator &() const { return s; }
119
120 operator const char *() const { return s == null () ? 0 : s; }
121
122protected:
123 // dummy is there so it isn't used as type converter accidentally
124 shstr_tmp (int dummy, const char *s)
125 : s(s)
126 {
127 }
128};
129
130inline bool operator ==(const shstr_tmp &a, const shstr_tmp &b)
131{
132 return a.s == b.s;
133}
134
135inline bool operator !=(const shstr_tmp &a, const shstr_tmp &b)
136{
137 return a.s != b.s;
138}
139
140inline int strlen (shstr_tmp sh)
141{
142 return sh.length ();
143}
144
145static inline std::ostream &operator <<(std::ostream &o, shstr_tmp sh)
146{
147 o.write (sh.s, sh.length ());
148
149 return o;
150}
151
152struct shstr : shstr_tmp
153{
154 static unsigned int &refcnt (const char *s)
155 {
156 return *((unsigned int *)s - 1);
157 }
158
159 unsigned int &refcnt () const
160 {
161 return refcnt (s);
162 }
163
164 shstr ()
165 {
166 }
167
168 static const char *find (const char *s);
169 static const char *intern (const char *s);
170
171 static void gc (); // garbage collect a few strings
172
173 shstr (const shstr &sh)
174 : shstr_tmp (sh)
175 {
176 ++refcnt ();
177 }
178
179 shstr (const shstr_tmp &sh)
180 : shstr_tmp (sh)
181 {
182 ++refcnt ();
183 }
184
185 explicit shstr (const char *str)
186 : shstr_tmp (0, is_constant (str) && !str ? null () : intern (str))
187 {
188 }
189
190 ~shstr ()
191 {
192 --refcnt ();
193 }
194
195 using shstr_tmp::operator &;
196 using shstr_tmp::operator const char *;
197
198 // (note: not the copy constructor)
199 shstr &operator =(const shstr_tmp &sh)
200 {
201 --refcnt ();
202 s = sh.s;
203 ++refcnt ();
204
205 return *this;
206 }
207
208 // here it comes
209 shstr &operator =(const shstr &sh)
210 {
211 return (*this) = (shstr_tmp)sh;
212 }
213
214 // shstr_tmp doesn't have this one
215 shstr &operator =(const char *str)
216 {
217 --refcnt ();
218 s = is_constant (str) && !str ? null () : intern (str);
219
220 return *this;
221 }
222};
223
224// only good for mass comparisons to shstr objects, or very
225// temporary passing, basically a non-refcounted shstr
226struct shstr_cmp
227{
228 const char *s;
229
230 // initialies to the non-matching string (as opposed to the null string)
231 shstr_cmp ()
232 {
233 s = 0;
234 }
235
236 shstr_cmp (const char *str)
237 : s (shstr::find (str))
238 {
239 }
240
241 shstr_cmp (shstr_tmp sh)
242 : s (sh.s)
243 {
244 }
245
246 // this is used for informational messages and the like
247 const char *operator &() const { return s; }
248
249 operator const char *() const { return s; }
250};
251
252inline bool operator ==(const shstr_cmp &a, const shstr_tmp &b)
253{
254 return a.s == b.s;
255}
256
257inline bool operator ==(const shstr_tmp &a, const shstr_cmp &b)
258{
259 return a.s == b.s;
260}
261
262#define def2(id,str) extern const shstr id;
263#define def(id) def2(shstr_ ## id, # id)
264# include "shstrinc.h"
265#undef def
266#undef def2
267
268// undefined external reference to catch people using str* functions when they shouldn't
269//template<class any> void strcmp (const shstr_tmp &a, any b);
270template<class any> void strstr (const shstr_tmp &a, any b);
271
15#endif 272#endif
16 273
17/* In the unlikely occurence that 16383 references to a string are too
18 * few, you can modify the below type to something bigger.
19 * (The top bit of "refcount" is used to signify that "u.array" points
20 * at the array entry.)
21 */
22#define REFCOUNT_TYPE int
23
24/* The offsetof macro is part of ANSI C, but many compilers lack it, for
25 * example "gcc -ansi"
26 */
27#if !defined (offsetof)
28#define offsetof(type, member) (int)&(((type *)0)->member)
29#endif
30
31/* SS(string) will return the address of the shared_string struct which
32 * contains "string".
33 */
34#define SS(x) ((shared_string *) ((x) - offsetof(shared_string, string)))
35
36#define SS_STATISTICS
37
38#define SS_DUMP_TABLE 1
39#define SS_DUMP_TOTALS 2
40
41#ifdef SS_STATISTICS
42static struct statistics {
43 int calls;
44 int hashed;
45 int strcmps;
46 int search;
47 int linked;
48} add_stats, add_ref_stats, free_stats, find_stats, hash_stats;
49#define GATHER(n) (++n)
50#else /* !SS_STATISTICS */
51#define GATHER(n)
52#endif /* SS_STATISTICS */
53
54#define TOPBIT ((unsigned REFCOUNT_TYPE) 1 << (sizeof(REFCOUNT_TYPE) * CHAR_BIT - 1))
55
56#define PADDING ((2 * sizeof(long) - sizeof(REFCOUNT_TYPE)) % sizeof(long)) + 1
57
58typedef struct _shared_string {
59 union {
60 struct _shared_string **array;
61 struct _shared_string *previous;
62 } u;
63 struct _shared_string *next;
64 /* The top bit of "refcount" is used to signify that "u.array" points
65 * at the array entry.
66 */
67 unsigned REFCOUNT_TYPE refcount;
68 /* Padding will be unused memory, since we can't know how large
69 * the padding when allocating memory. We assume here that
70 * sizeof(long) is a good boundary.
71 */
72 char string[PADDING];
73} shared_string;
74
75extern void init_hash_table(void);
76extern const char *add_string(const char *str);
77extern const char *add_refcount(const char *str);
78extern int query_refcount(const char *str);
79extern const char *find_string(const char *str);
80extern void free_string(const char *str);
81extern void ss_dump_statistics(void);
82extern const char *ss_dump_table(int what);
83extern int buf_overflow(const char *buf1, const char *buf2, int bufsize);
84
85#endif
86

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