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Comparing deliantra/server/include/shstr.h (file contents):
Revision 1.2 by root, Sat Aug 26 23:36:32 2006 UTC vs.
Revision 1.18 by root, Tue Jul 10 05:51:38 2007 UTC

1/*
2 * This file is part of Crossfire TRT, the Roguelike Realtime MORPG.
3 *
4 * Copyright (©) 2005,2006,2007 Marc Alexander Lehmann / Robin Redeker / the Crossfire TRT team
5 *
6 * Crossfire TRT 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 <crossfire@schmorp.de>
20 */
21
1#ifndef SHSTR_H__ 22#ifndef SHSTR_H__
2#define SHSTR_H__ 23#define SHSTR_H__
3 24
4/* The size of the shared strings hashtable. This must be smaller than 25#include <sstream>
5 * 32767, but 947 ought to be plenty enough.
6 */
7#define TABLESIZE 4133
8 26
9/* This specifies how many characters the hashing routine should look at. 27#include "util.h"
10 * You may actually save CPU by increasing this number if the typical string 28
11 * is large. 29extern int buf_overflow (const char *buf1, const char *buf2, int bufsize);
12 */ 30
13#ifndef MAXSTRING 31struct shstr
14#define MAXSTRING 20 32{
33 static const char *null;
34
35 const char *s;
36
37 static int &refcnt (const char *s)
38 {
39 return *((int *)s - 1);
40 }
41
42 static int &length (const char *s)
43 {
44 return *((int *)s - 2);
45 }
46
47 int &refcnt () const
48 {
49 return refcnt (s);
50 }
51
52 int length () const
53 {
54 return length (s);
55 }
56
57 // returns wether this shared string begins with the given prefix,
58 // used mainly for searched when users give only the start of a name.
59 bool begins_with (const char *prefix) const
60 {
61 int plen = strlen (prefix);
62 return !strncasecmp (s, prefix, plen) && length () >= plen;
63 }
64
65 static const char *find (const char *s);
66 static const char *intern (const char *s);
67
68 static void gc (); // garbage collect a few strings
69
70 // this is used for informational messages and the like
71 const char *operator &() const { return s; }
72
73 const char &operator [](int i) const { return s[i]; }
74 operator const char *() const { return s == null ? 0 : s; }
75
76 shstr ()
77 : s (null)
78 {
79 }
80
81 shstr (const shstr &sh)
82 : s (sh.s)
83 {
84 ++refcnt ();
85 }
86
87 explicit shstr (const char *s)
88 : s (intern (s))
89 {
90 }
91
92 ~shstr ()
93 {
94 --refcnt ();
95 }
96
97 const shstr &operator =(const shstr &sh)
98 {
99 --refcnt ();
100 s = sh.s;
101 ++refcnt ();
102
103 return *this;
104 }
105
106 const shstr &operator =(const char *str)
107 {
108 --refcnt ();
109
110 // this optimises the important case of str == constant 0
111 if (is_constant (str))
112 s = str ? intern (str) : null;
113 else
114 s = intern (str);
115
116 return *this;
117 }
118
119 bool operator ==(const shstr &b)
120 {
121 return s == b.s;
122 }
123
124 bool operator !=(const shstr &b)
125 {
126 return !(*this == b);
127 }
128};
129
130inline int strlen (const shstr &sh)
131{
132 return sh.length ();
133}
134
135inline int strcmp (const shstr &a, const shstr &b)
136{
137 // TODO: use this to find all the occurences of people using strcmp
138 // all uses should be bogus, as we should be never interested in
139 // comparing shstr's alphabetically
140#if 0
141 extern void do_not_use_strcmp_to_compare_shstr_values ();
142 do_not_use_strcmp_to_compare_shstr_values ();
15#endif 143#endif
144 return a != b;
145}
16 146
17/* In the unlikely occurence that 16383 references to a string are too 147static std::ostream &operator <<(std::ostream &o, const shstr &sh)
18 * few, you can modify the below type to something bigger. 148{
19 * (The top bit of "refcount" is used to signify that "u.array" points 149 o.write (sh.s, sh.length ());
20 * at the array entry.) 150 return o;
21 */ 151}
22#define REFCOUNT_TYPE int
23 152
24/* The offsetof macro is part of ANSI C, but many compilers lack it, for 153// only good for mass comparisons to shstr objects
25 * example "gcc -ansi" 154struct shstr_cmp
26 */ 155{
27#if !defined (offsetof) 156 const char *s;
28#define offsetof(type, member) (int)&(((type *)0)->member)
29#endif
30 157
31/* SS(string) will return the address of the shared_string struct which 158 explicit shstr_cmp (const char *s)
32 * contains "string". 159 : s (shstr::find (s))
33 */ 160 {
34#define SS(x) ((shared_string *) ((x) - offsetof(shared_string, string))) 161 }
35 162
36#define SS_STATISTICS 163 shstr_cmp (const shstr_cmp &sh)
164 : s (sh.s)
165 {
166 }
37 167
38#define SS_DUMP_TABLE 1 168 shstr_cmp &operator =(const shstr_cmp sh) { s = sh.s; return *this; }
39#define SS_DUMP_TOTALS 2 169 operator const char *() const { return s; }
170};
40 171
41#ifdef SS_STATISTICS 172inline bool operator ==(const shstr_cmp &a, const shstr &b)
42static struct statistics { 173{
43 int calls; 174 return a.s == b.s;
44 int hashed; 175}
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 */
53 176
54#define TOPBIT ((unsigned REFCOUNT_TYPE) 1 << (sizeof(REFCOUNT_TYPE) * CHAR_BIT - 1)) 177inline bool operator ==(const shstr &a, const shstr_cmp &b)
178{
179 return b == a;
180}
55 181
56#define PADDING ((2 * sizeof(long) - sizeof(REFCOUNT_TYPE)) % sizeof(long)) + 1 182#define def(str) extern const shstr shstr_ ## str;
57 183# include "shstrinc.h"
58typedef struct _shared_string { 184#undef def
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);
84 185
85#endif 186#endif
86 187

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