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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 1.19 by root, Tue Oct 16 05:34:24 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 size_t shstr_alloc;
12 */ 30
13#ifndef MAXSTRING 31extern int buf_overflow (const char *buf1, const char *buf2, int bufsize);
14#define MAXSTRING 20 32
33struct shstr
34{
35 static const char *null;
36
37 const char *s;
38
39 static int &refcnt (const char *s)
40 {
41 return *((int *)s - 1);
42 }
43
44 static int &length (const char *s)
45 {
46 return *((int *)s - 2);
47 }
48
49 int &refcnt () const
50 {
51 return refcnt (s);
52 }
53
54 int length () const
55 {
56 return length (s);
57 }
58
59 // returns wether this shared string begins with the given prefix,
60 // used mainly for searched when users give only the start of a name.
61 bool begins_with (const char *prefix) const
62 {
63 int plen = strlen (prefix);
64 return !strncasecmp (s, prefix, plen) && length () >= plen;
65 }
66
67 static const char *find (const char *s);
68 static const char *intern (const char *s);
69
70 static void gc (); // garbage collect a few strings
71
72 // this is used for informational messages and the like
73 const char *operator &() const { return s; }
74
75 const char &operator [](int i) const { return s[i]; }
76 operator const char *() const { return s == null ? 0 : s; }
77
78 shstr ()
79 : s (null)
80 {
81 }
82
83 shstr (const shstr &sh)
84 : s (sh.s)
85 {
86 ++refcnt ();
87 }
88
89 explicit shstr (const char *s)
90 : s (intern (s))
91 {
92 }
93
94 ~shstr ()
95 {
96 --refcnt ();
97 }
98
99 const shstr &operator =(const shstr &sh)
100 {
101 --refcnt ();
102 s = sh.s;
103 ++refcnt ();
104
105 return *this;
106 }
107
108 const shstr &operator =(const char *str)
109 {
110 --refcnt ();
111
112 // this optimises the important case of str == constant 0
113 if (is_constant (str))
114 s = str ? intern (str) : null;
115 else
116 s = intern (str);
117
118 return *this;
119 }
120
121 bool operator ==(const shstr &b)
122 {
123 return s == b.s;
124 }
125
126 bool operator !=(const shstr &b)
127 {
128 return !(*this == b);
129 }
130};
131
132inline int strlen (const shstr &sh)
133{
134 return sh.length ();
135}
136
137inline int strcmp (const shstr &a, const shstr &b)
138{
139 // TODO: use this to find all the occurences of people using strcmp
140 // all uses should be bogus, as we should be never interested in
141 // comparing shstr's alphabetically
142#if 0
143 extern void do_not_use_strcmp_to_compare_shstr_values ();
144 do_not_use_strcmp_to_compare_shstr_values ();
15#endif 145#endif
146 return a != b;
147}
16 148
17/* In the unlikely occurence that 16383 references to a string are too 149static std::ostream &operator <<(std::ostream &o, const shstr &sh)
18 * few, you can modify the below type to something bigger. 150{
19 * (The top bit of "refcount" is used to signify that "u.array" points 151 o.write (sh.s, sh.length ());
20 * at the array entry.) 152 return o;
21 */ 153}
22#define REFCOUNT_TYPE int
23 154
24/* The offsetof macro is part of ANSI C, but many compilers lack it, for 155// only good for mass comparisons to shstr objects
25 * example "gcc -ansi" 156struct shstr_cmp
26 */ 157{
27#if !defined (offsetof) 158 const char *s;
28#define offsetof(type, member) (int)&(((type *)0)->member)
29#endif
30 159
31/* SS(string) will return the address of the shared_string struct which 160 explicit shstr_cmp (const char *s)
32 * contains "string". 161 : s (shstr::find (s))
33 */ 162 {
34#define SS(x) ((shared_string *) ((x) - offsetof(shared_string, string))) 163 }
35 164
36#define SS_STATISTICS 165 shstr_cmp (const shstr_cmp &sh)
166 : s (sh.s)
167 {
168 }
37 169
38#define SS_DUMP_TABLE 1 170 shstr_cmp &operator =(const shstr_cmp sh) { s = sh.s; return *this; }
39#define SS_DUMP_TOTALS 2 171 operator const char *() const { return s; }
172};
40 173
41#ifdef SS_STATISTICS 174inline bool operator ==(const shstr_cmp &a, const shstr &b)
42static struct statistics { 175{
43 int calls; 176 return a.s == b.s;
44 int hashed; 177}
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 */
53 178
54#define TOPBIT ((unsigned REFCOUNT_TYPE) 1 << (sizeof(REFCOUNT_TYPE) * CHAR_BIT - 1)) 179inline bool operator ==(const shstr &a, const shstr_cmp &b)
180{
181 return b == a;
182}
55 183
56#define PADDING ((2 * sizeof(long) - sizeof(REFCOUNT_TYPE)) % sizeof(long)) + 1 184#define def(str) extern const shstr shstr_ ## str;
57 185# include "shstrinc.h"
58typedef struct _shared_string { 186#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);
84 187
85#endif 188#endif
86 189

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