1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
|
/*
* stringbuf.h: interface for the String buffering module.
*
* daniel@veillard.com
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#include "stringbuf.h"
#include "memory.h"
/*
* Not the default, too heavy on CPU ...
*/
#ifdef WITH_STRING_BUF
#define CLEANUP_FREQUENCY 2000
/*
* An hash table for the Strings
*/
#define HASH_SIZE 65536
typedef struct stringHash {
struct stringHash *next; /* next clash in the hash table */
int use; /* number of references */
const char *val; /* the string value */
} stringHash, *stringHashPtr;
stringHashPtr stringHashTable[HASH_SIZE];
/*
* Hash table initialization.
*/
static int stringHashInitialized = 0;
static void stringHashInitialize(void) {
int i;
for (i = 0; i < HASH_SIZE; i++) {
stringHashTable[i] = NULL;
}
stringHashInitialized = 1;
}
/*
* Compute an hash key
*/
static int stringGetHash(const char *str) {
unsigned short res = 0;
while (*str != 0) res += *(str++);
return((int) (res % HASH_SIZE));
}
/*
* Cleanup the hash table for unused entries
*/
void stringTableCleanup(void) {
int key;
int used = 0, entries = 0;
stringHashPtr cur;
stringHashPtr prev;
for (key =0;key < HASH_SIZE;key++) {
if (stringHashTable[key] != NULL) used++;
while (stringHashTable[key] != NULL) {
if (stringHashTable[key]->use == 0) {
cur = stringHashTable[key]->next;
stringHashTable[key]->val = NULL;
stringHashTable[key]->use = 0;
stringHashTable[key]->next = NULL;
xmlFree(stringHashTable[key]);
stringHashTable[key] = cur;
} else {
entries++;
prev = stringHashTable[key];
cur = stringHashTable[key]->next;
while (cur != NULL) {
if (cur->use == 0) {
xmlFree(cur->val);
prev->next = cur->next;
cur->next = NULL;
xmlFree(cur);
cur = prev->next;
} else {
entries++;
prev = cur;
cur = cur->next;
}
}
goto next_key;
}
}
next_key:
}
printf("String Buffer: %d entries, %d hash\n", entries, used);
}
/*
* Duplicate an "external" string. Search the string in the
* list if not found, add it, otherwise increment the counter.
*/
const char *stringAdd(const char *str) {
int key;
stringHashPtr cur;
static int toCleanup = CLEANUP_FREQUENCY;
if (stringHashInitialized == 0) stringHashInitialize();
toCleanup--;
if (toCleanup <= 0) {
toCleanup = CLEANUP_FREQUENCY;
stringTableCleanup();
}
key = stringGetHash(str);
cur = stringHashTable[key];
while (cur != NULL) {
if (!strcmp(str, cur->val)) {
cur->use++;
return(cur->val);
}
cur = cur->next;
}
cur = xmlMalloc(sizeof(stringHash));
cur->val = xmlStrdup(str);
cur->use = 1;
cur->next = stringHashTable[key];
stringHashTable[key] = cur;
return(cur->val);
}
/*
* Free a duplicate of the string. Decrement the counter, if zero,
* free the string and remove it from the list.
*/
void stringFree(const char *str) {
int key;
stringHashPtr cur;
key = stringGetHash(str);
cur = stringHashTable[key];
while (cur != NULL) {
if (!strcmp(str, cur->val)) {
cur->use--;
/* TODO : garbage collect ... */
return;
}
cur = cur->next;
}
printf("stringFree : %s not found !\n", str);
}
#else /* ! WITH_STRING_BUF */
const char *stringAdd(const char *str) {
return(xmlStrdup(str));
}
void stringFree(const char *str) {
xmlFree((char *) str);
}
#endif /* !WITH_STRING_BUF */
|
