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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 1.30 by root, Thu Jan 1 16:05:12 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 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>
3 */ 20 */
4#define TABLESIZE 4133
5 21
6/* This specifies how many characters the hashing routine should look at. 22#ifndef SHSTR_H__
7 * You may actually save CPU by increasing this number if the typical string 23#define SHSTR_H__
8 * is large. 24
9 */ 25#include <cstring>
10#ifndef MAXSTRING 26#include <sstream>
11#define MAXSTRING 20 27
28#include "traits.h"
29
30extern size_t shstr_alloc;
31
32extern int buf_overflow (const char *buf1, const char *buf2, int bufsize);
33
34template<int size>
35struct 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.
47struct 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 s != null () && strstr (s, substring);
76 }
77
78 //TODO: case sensitive should be eradicated
79 bool eq_nc (const char *otherstring) const
80 {
81 return !strcasecmp (s, otherstring);
82 }
83
84 shstr_tmp ()
85 : s (null ())
86 {
87 }
88
89 shstr_tmp (const shstr_tmp &sh)
90 : s (sh.s)
91 {
92 }
93
94 shstr_tmp operator =(const shstr_tmp &sh)
95 {
96 s = sh.s;
97
98 return *this;
99 }
100
101 // this is used for informational messages and the like
102 const char *operator &() const { return s; }
103
104 operator const char *() const { return s == null () ? 0 : s; }
105
106protected:
107 // dummy is there so it isn't used as type converter accidentally
108 shstr_tmp (int dummy, const char *s)
109 : s(s)
110 {
111 }
112};
113
114inline bool operator ==(const shstr_tmp &a, const shstr_tmp &b)
115{
116 return a.s == b.s;
117}
118
119inline bool operator !=(const shstr_tmp &a, const shstr_tmp &b)
120{
121 return a.s != b.s;
122}
123
124inline int strlen (const shstr_tmp &sh)
125{
126 return sh.length ();
127}
128
129static std::ostream &operator <<(std::ostream &o, shstr_tmp sh)
130{
131 o.write (sh.s, sh.length ());
132
133 return o;
134}
135
136struct shstr : shstr_tmp
137{
138 static unsigned int &refcnt (const char *s)
139 {
140 return *((unsigned int *)s - 1);
141 }
142
143 unsigned int &refcnt () const
144 {
145 return refcnt (s);
146 }
147
148 shstr ()
149 {
150 }
151
152 static const char *find (const char *s);
153 static const char *intern (const char *s);
154
155 static void gc (); // garbage collect a few strings
156
157 shstr (const shstr &sh)
158 : shstr_tmp (sh)
159 {
160 ++refcnt ();
161 }
162
163 shstr (const shstr_tmp &sh)
164 : shstr_tmp (sh)
165 {
166 ++refcnt ();
167 }
168
169 explicit shstr (const char *str)
170 : shstr_tmp (0, is_constant (str) && !str ? null () : intern (str))
171 {
172 }
173
174 ~shstr ()
175 {
176 --refcnt ();
177 }
178
179 using shstr_tmp::operator &;
180 using shstr_tmp::operator const char *;
181
182 // (note: not the copy constructor)
183 shstr &operator =(const shstr_tmp &sh)
184 {
185 --refcnt ();
186 s = sh.s;
187 ++refcnt ();
188
189 return *this;
190 }
191
192 // here it comes
193 shstr &operator =(const shstr &sh)
194 {
195 return (*this) = (shstr_tmp)sh;
196 }
197
198 // shstr_tmp doesn't have this one
199 shstr &operator =(const char *str)
200 {
201 --refcnt ();
202 s = is_constant (str) && !str ? null () : intern (str);
203
204 return *this;
205 }
206};
207
208// only good for mass comparisons to shstr objects, or very
209// temporary passing, basically a non-refcounted shstr
210struct shstr_cmp
211{
212 const char *s;
213
214 // initialies to the non-matching string (as opposed to the null string)
215 shstr_cmp ()
216 {
217 s = 0;
218 }
219
220 shstr_cmp (const char *str)
221 : s (shstr::find (str))
222 {
223 }
224
225 shstr_cmp (shstr_tmp sh)
226 : s (sh.s)
227 {
228 }
229
230 // this is used for informational messages and the like
231 const char *operator &() const { return s; }
232
233 operator const char *() const { return s; }
234};
235
236inline bool operator ==(const shstr_cmp &a, const shstr_tmp &b)
237{
238 return a.s == b.s;
239}
240
241inline bool operator ==(const shstr_tmp &a, const shstr_cmp &b)
242{
243 return a.s == b.s;
244}
245
246#define def2(id,str) extern const shstr id;
247#define def(id) def2(shstr_ ## id, # id)
248# include "shstrinc.h"
249#undef def
250#undef def2
251
252// undefined external reference to catch people using str* functions when they shouldn't
253//template<class any> void strcmp (const shstr_tmp &a, any b);
254template<class any> void strstr (const shstr_tmp &a, any b);
255
12#endif 256#endif
13 257
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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