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Comparing deliantra/server/include/shstr.h (file contents):
Revision 1.1.1.1 by root, Fri Feb 3 07:12:50 2006 UTC vs.
Revision 1.47 by root, Wed Dec 5 22:09:21 2018 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 (©) 2017,2018 Marc Alexander Lehmann / the Deliantra team
5 * Copyright (©) 2005,2006,2007,2008,2009,2010,2011,2012,2013,2014,2015,2016 Marc Alexander Lehmann / Robin Redeker / the Deliantra team
6 *
7 * Deliantra is free software: you can redistribute it and/or modify it under
8 * the terms of the Affero GNU General Public License as published by the
9 * Free Software Foundation, either version 3 of the License, or (at your
10 * option) any later version.
11 *
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
16 *
17 * You should have received a copy of the Affero GNU General Public License
18 * and the GNU General Public License along with this program. If not, see
19 * <http://www.gnu.org/licenses/>.
20 *
21 * The authors can be reached via e-mail to <support@deliantra.net>
3 */ 22 */
4#define TABLESIZE 4133
5 23
6/* This specifies how many characters the hashing routine should look at. 24#ifndef SHSTR_H__
7 * You may actually save CPU by increasing this number if the typical string 25#define SHSTR_H__
8 * is large. 26
9 */ 27#include <cstring>
10#ifndef MAXSTRING 28#include <sstream>
11#define MAXSTRING 20 29
30#include "traits.h"
31
32extern size_t shstr_alloc;
33
34extern int buf_overflow (const char *buf1, const char *buf2, int bufsize);
35
36template<int size>
37struct shstr_vec
38{
39 uint32_t hash;
40 uint32_t len;
41 uint32_t refcnt;
42 // pointer points here
43 char string [size];
44};
45
46// this class is a non-refcounted shared string
47// it cannot be used to create or store shared strings, but
48// it can be used to pass shared strings around, i.e. as function arguments
49// or return values. their lifetime must not span a gc () call, i.e.
50// they are only valid as temporary values within the same server tick.
51struct shstr_tmp
52{
53 static shstr_vec<sizeof ("(null)")> nullvec;
54 static const char *null () { return nullvec.string; } // this is the null pointer value
55
56 const char *s;
57
58 static unsigned int &hash (const char *s)
59 {
60 return *((unsigned int *)s - 3);
61 }
62
63 int hash () const
64 {
65 return hash (s);
66 }
67
68 static unsigned int &length (const char *s)
69 {
70 return *((unsigned int *)s - 2);
71 }
72
73 int length () const
74 {
75 return length (s);
76 }
77
78 // returns whether this shared string begins with the given prefix,
79 // used mainly for searches when users give only the start of a name.
80 bool starts_with (const char *prefix) const
81 {
82 int plen = strlen (prefix);
83
84 return length () >= plen && !strncasecmp (s, prefix, plen);
85 }
86
87 // returns true if the substring is contained in the shstr
88 // if the shstr is 0, then this always returns false.
89 // the shstr is (theoretically) treated as a comma/colon/space etc. separated list.
90 bool contains (const char *substring) const;
91
92 //TODO: case sensitive should be eradicated
93 bool eq_nc (const char *otherstring) const
94 {
95 return !strcasecmp (s, otherstring);
96 }
97
98 shstr_tmp ()
99 : s (null ())
100 {
101 }
102
103 shstr_tmp (const shstr_tmp &sh)
104 : s (sh.s)
105 {
106 }
107
108 shstr_tmp operator =(const shstr_tmp &sh)
109 {
110 s = sh.s;
111
112 return *this;
113 }
114
115 // this is used for informational messages and the like
116 const char *operator &() const { return s; }
117
118 operator const char *() const { return s == null () ? 0 : s; }
119
120protected:
121 // dummy is there so it isn't used as type converter accidentally
122 shstr_tmp (int dummy, const char *s)
123 : s(s)
124 {
125 }
126};
127
128inline bool operator ==(const shstr_tmp &a, const shstr_tmp &b)
129{
130 return a.s == b.s;
131}
132
133inline bool operator !=(const shstr_tmp &a, const shstr_tmp &b)
134{
135 return a.s != b.s;
136}
137
138inline int strlen (shstr_tmp sh)
139{
140 return sh.length ();
141}
142
143static inline std::ostream &operator <<(std::ostream &o, shstr_tmp sh)
144{
145 o.write (sh.s, sh.length ());
146
147 return o;
148}
149
150struct shstr : shstr_tmp
151{
152 static unsigned int &refcnt (const char *s)
153 {
154 return *((unsigned int *)s - 1);
155 }
156
157 unsigned int &refcnt () const
158 {
159 return refcnt (s);
160 }
161
162 shstr ()
163 {
164 }
165
166 static const char *find (const char *s);
167 static const char *intern (const char *s);
168
169 static void gc (); // garbage collect a few strings
170
171 shstr (const shstr &sh)
172 : shstr_tmp (sh)
173 {
174 ++refcnt ();
175 }
176
177 shstr (const shstr_tmp &sh)
178 : shstr_tmp (sh)
179 {
180 ++refcnt ();
181 }
182
183 explicit shstr (const char *str)
184 : shstr_tmp (0, ecb_is_constant (str) && !str ? null () : intern (str))
185 {
186 }
187
188 ~shstr ()
189 {
190 --refcnt ();
191 }
192
193 using shstr_tmp::operator &;
194 using shstr_tmp::operator const char *;
195
196 // (note: not the copy constructor)
197 shstr &operator =(const shstr_tmp &sh)
198 {
199 --refcnt ();
200 s = sh.s;
201 ++refcnt ();
202
203 return *this;
204 }
205
206 // here it comes
207 shstr &operator =(const shstr &sh)
208 {
209 return (*this) = (shstr_tmp)sh;
210 }
211
212 // shstr_tmp doesn't have this one
213 shstr &operator =(const char *str)
214 {
215 --refcnt ();
216 s = ecb_is_constant (str) && !str ? null () : intern (str);
217
218 return *this;
219 }
220};
221
222// only good for mass comparisons to shstr objects, or very
223// temporary passing, basically a non-refcounted shstr
224struct shstr_cmp
225{
226 const char *s;
227
228 // initialies to the non-matching string (as opposed to the null string)
229 shstr_cmp ()
230 {
231 s = 0;
232 }
233
234 shstr_cmp (const char *str)
235 : s (shstr::find (str))
236 {
237 }
238
239 shstr_cmp (shstr_tmp sh)
240 : s (sh.s)
241 {
242 }
243
244 // this is used for informational messages and the like
245 const char *operator &() const { return s; }
246
247 operator const char *() const { return s; }
248};
249
250inline bool operator ==(const shstr_cmp &a, const shstr_tmp &b)
251{
252 return a.s == b.s;
253}
254
255inline bool operator ==(const shstr_tmp &a, const shstr_cmp &b)
256{
257 return a.s == b.s;
258}
259
260#define def2(id,str) extern const shstr id;
261#define def(id) def2(shstr_ ## id, # id)
262# include "shstrinc.h"
263#undef def
264#undef def2
265
266// undefined external reference to catch people using str* functions when they shouldn't
267//template<class any> void strcmp (const shstr_tmp &a, any b);
268template<class any> void strstr (const shstr_tmp &a, any b);
269
12#endif 270#endif
13 271
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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