ViewVC Help
View File | Revision Log | Show Annotations | Download File
/cvs/deliantra/server/include/shstr.h
(Generate patch)

Comparing deliantra/server/include/shstr.h (file contents):
Revision 1.3 by root, Tue Aug 29 08:01:36 2006 UTC vs.
Revision 1.8 by root, Sun Sep 3 23:33:01 2006 UTC

1#ifndef SHSTR_H__ 1#ifndef SHSTR_H__
2#define SHSTR_H__ 2#define SHSTR_H__
3 3
4/* The size of the shared strings hashtable. This must be smaller than 4#include "util.h"
5 * 32767, but 947 ought to be plenty enough.
6 */
7#define TABLESIZE 4133
8 5
9/* This specifies how many characters the hashing routine should look at. 6extern int buf_overflow (const char *buf1, const char *buf2, int bufsize);
10 * You may actually save CPU by increasing this number if the typical string 7
11 * is large. 8struct shstr
12 */ 9{
13#ifndef MAXSTRING 10 static const char *null;
14#define MAXSTRING 20 11
12 const char *s;
13
14 static int &refcnt (const char *s)
15 {
16 return *((int *)s - 1);
17 }
18
19 static int &length (const char *s)
20 {
21 return *((int *)s - 2);
22 }
23
24 int &refcnt () const
25 {
26 return refcnt (s);
27 }
28
29 int length () const
30 {
31 return length (s);
32 }
33
34 static const char *find (const char *s);
35 static const char *intern (const char *s);
36
37 static void gc (); // garbage collect a few strings
38
39 // this is used for informational messages and the like
40 const char *operator &() const { return s; }
41
42 const char &operator [](int i) const { return s[i]; }
43 operator const char *() const { return s == null ? 0 : s; }
44
45 shstr ()
46 : s (null)
47 {
48 }
49
50 shstr (const shstr &sh)
51 : s (sh.s)
52 {
53 ++refcnt ();
54 }
55
56 explicit shstr (const char *s)
57 : s (intern (s))
58 {
59 }
60
61 ~shstr ()
62 {
63 --refcnt ();
64 }
65
66 const shstr &operator =(const shstr &sh)
67 {
68 --refcnt ();
69 s = sh.s;
70 ++refcnt ();
71
72 return *this;
73 }
74
75 const shstr &operator =(const char *str)
76 {
77 --refcnt ();
78
79#if 0
80 // this optimises the important case of str == constant 0
81 if (is_constant (str))
82 s = str ? intern (str) : null;
83 else
15#endif 84#endif
85 s = intern (str);
16 86
17/* In the unlikely occurence that 16383 references to a string are too 87 return *this;
18 * few, you can modify the below type to something bigger. 88 }
19 * (The top bit of "refcount" is used to signify that "u.array" points 89};
20 * at the array entry.)
21 */
22#define REFCOUNT_TYPE int
23 90
24/* The offsetof macro is part of ANSI C, but many compilers lack it, for 91inline int strlen (const shstr &sh)
25 * example "gcc -ansi" 92{
26 */ 93 return sh.length ();
27#if !defined (offsetof) 94}
28#define offsetof(type, member) (int)&(((type *)0)->member)
29#endif
30 95
31/* SS(string) will return the address of the shared_string struct which 96inline bool operator ==(const shstr &a, const shstr &b)
32 * contains "string". 97{
33 */ 98 return a.s == b.s;
34#define SS(x) ((shared_string *) ((x) - offsetof(shared_string, string))) 99}
35 100
36#define SS_STATISTICS 101inline bool operator !=(const shstr &a, const shstr &b)
37 102{
38#define SS_DUMP_TABLE 1 103 return !(a == b);
39#define SS_DUMP_TOTALS 2 104}
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);
84 105
85#endif 106#endif
86 107

Diff Legend

– Removed lines
+ Added lines
< Changed lines
> Changed lines