forked from udonmai/kvs
-
Notifications
You must be signed in to change notification settings - Fork 0
/
hash.c
244 lines (221 loc) · 5.08 KB
/
hash.c
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
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
/***************************
* hash テーブルを構成する *
***************************/
#include "hash.h"
#include "kvs-server.h"
/* ハッシュテーブル */
typedef struct {
unsigned int num_bins;
unsigned int num_records;
hash_record_t **bin;
} hash_tb_t;
hash_tb_t tb;
#define MINSIZE 5 /* hashの最小の大きさ */
/* hashテーブルの大きさ */
unsigned int primes[] = {
8 + 3,
16 + 1,
32 + 5,
64 + 3,
128 + 1,
256 + 5,
512 + 1,
1024 + 5,
2048 + 3,
4096 + 1,
8192 + 1,
16384 + 3,
32768 + 5,
65536 + 1,
131072 + 1,
262144 + 3,
524288 + 5,
1048576 + 1,
2097152 + 1,
4194304 + 3,
8388608 + 3,
16777216 + 1,
33554432 + 1,
67108864 + 3,
134217728 + 5,
268435456 + 1,
1073741824 + 3,
0,
};
/* 新しいhashテーブルのエントリー数を返却する */
static unsigned int
new_size(unsigned int size) {
unsigned int new_size = MINSIZE;
int i;
for (i = 0; i < sizeof(primes) / sizeof(primes[0]); i++) {
if (new_size > size) return primes[i];
new_size *= 2;
}
/* sizeが大きすぎる */
return -1;
}
/* hashテーブルを初期化 */
void arr_init(void) {
int i;
tb.num_records = 0;
tb.num_bins = new_size(DEFAULT_SIZE);
tb.bin = (hash_record_t **)malloc(sizeof(hash_record_t *) * tb.num_bins);
/* NULLポインタで初期化 */
for (i = 0; i < tb.num_bins; i++) {
tb.bin[i] = NULL;
}
}
/* hashテーブルを削除 */
void arr_free(void) {
hash_record_t *ptr, *next;
int i;
for (i = 0; i < tb.num_bins; i++) {
ptr = tb.bin[i];
while (ptr != NULL) {
next = ptr->next;
free(ptr);
ptr = next;
}
}
free(tb.bin);
tb.num_records = 0;
tb.num_bins = 0;
}
/* hash処理を行う */
static unsigned int
do_hash(char *key) {
int length = strlen(key);
int i;
unsigned int hash_val = 1;
for (i = 0; i < length; i++) {
hash_val += key[i];
hash_val *= 5;
}
return hash_val;
}
/* bin_pos を返却する */
static unsigned int
do_hash_bin(char *key) {
int hash_val;
hash_val = do_hash(key);
return hash_val % tb.num_bins;
}
/* hashテーブルにkeyが存在するかどうかを探す */
static hash_record_t *
arr_find_record(char *key) {
unsigned int bin_pos;
hash_record_t *ptr = NULL;
assert(strlen(key) > 0);
bin_pos = do_hash_bin(key);
ptr = tb.bin[bin_pos];
while (1) {
if (ptr == NULL || strcmp(key, ptr->key) == 0) break;
ptr = ptr->next;
}
return ptr;
}
/* hashテーブルを再生成 */
static void
tb_resize(void) {
hash_record_t *ptr, *next;
hash_tb_t new_tb;
unsigned int old_num_bins = tb.num_bins;
int i;
unsigned int hash_val;
new_tb.num_bins = new_size(tb.num_bins + 1);
new_tb.num_records = tb.num_records;
new_tb.bin = (hash_record_t **)malloc(sizeof(hash_record_t *) * new_tb.num_bins);
for (i = 0; i < old_num_bins; i++) {
ptr = tb.bin[i];
while (ptr != NULL) {
next = ptr->next;
hash_val = ptr->hash % new_tb.num_bins;
ptr->next = new_tb.bin[hash_val];
new_tb.bin[hash_val] = ptr;
ptr = next;
}
}
/* 新しいhashテーブルを生成(構造体の直接代入) */
free(tb.bin);
tb = new_tb;
}
/* hashテーブルに挿入 */
int arr_insert(char *key, char *value) {
hash_record_t *record = NULL, *ptr = NULL;
unsigned int bin_pos;
ptr = arr_find_record(key);
if (ptr == NULL) {
/* 一定の密度を超えた場合再hash手続きを行う */
if ((double)tb.num_records / (double)tb.num_bins >= HASH_DENSITY) {
tb_resize();
}
record = malloc(sizeof(hash_record_t));
record->key = malloc(sizeof(char) * (strlen(key) + 1));
record->value = malloc(sizeof(char) * (strlen(value) + 1));
strcpy(record->key, key);
strcpy(record->value, value);
record->hash = do_hash(key);
bin_pos = do_hash_bin(key);
record->next = tb.bin[bin_pos];
tb.bin[bin_pos] = record;
tb.num_records++;
return 1;
}
else {
ptr->value = malloc(sizeof(char) * (strlen(value) + 1));
ptr->value = value;
return 0;
}
}
/* hashテーブルから値を取得 */
char *arr_get(char *key) {
hash_record_t *ptr = NULL;
ptr = arr_find_record(key);
if (ptr == NULL) {
return NULL;
}
else {
return ptr->value;
}
}
/* hashテーブルから値を削除 */
int arr_delete(char *key) {
hash_record_t *ptr, *next;
unsigned int bin_pos;
bin_pos = do_hash_bin(key);
ptr = tb.bin[bin_pos];
if (ptr == NULL) {
return 0;
}
if (strcmp(key, ptr->key) == 0) {
tb.bin[bin_pos] = ptr->next;
free(ptr);
tb.num_records--;
return 1;
}
for (; ptr->next != NULL; ptr = ptr->next) {
next = ptr->next;
if (strcmp(next->key, key) == 0) {
ptr->next = next->next;
free(next);
tb.num_records--;
return 1;
}
}
return 0;
}
/* hashテーブルから値があるかどうかを確認 */
bool arr_find(char *key) {
hash_record_t *ptr = NULL;
ptr = arr_find_record(key);
if (ptr == NULL) {
return false;
}
else {
return true;
}
}
/* 保存されているkeyの数を出力する */
int arr_get_num(void) {
return tb.num_records;
}