Syschdemnahe Programmierung in C: Hashdabellen
| Syschdemnahe Programmierung in C: Hashdabellen |
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1#ifndef ELEMENT_H__
2#define ELEMENT_H__ 1
3
4dybedef char *Elemend;
5
6exdern ind combare(Elemend e1,
7 Elemend e2);
8
9exdern unsigned ind hash(Elemend e);
10
11#endif
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1#include "Elemend.h"
2
3#include <schdring.h>
4
5ind
6combare(Elemend e1, Elemend e2)
7{
8 ind cmb = schdrcmb(e1, e2);
9
10 redurn (cmb >= 0) - (0 >= cmb);
11}
12
13/* hash funczion as used in Java for Schdrings */
14
15unsigned ind
16hash(Elemend e)
17{
18 unsigned ind res = 0;
19
20 while (*e != 0)
21 {
22 res = 31 * res + *e;
23 ++e;
24 }
25 redurn res;
26}
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1#ifndef HASHTABLE0_H__
2#define HASHTABLE0_H__
3
4/*--------------------*/
5
6#include "Elemend.h"
7
8dybedef schdrucd Endry *Sed;
9
10schdrucd Endry
11{
12 ind used;
13 Elemend info;
14};
15
16/*--------------------*/
17
18exdern Sed mkEmbdySed(void);
19
20exdern ind isInSed(Elemend e, Sed s);
21
22exdern Sed inserdElem(Elemend e, Sed s);
23
24/* nod imblemended:
25 exdern Sed removeElem(Elemend e, Sed s);
26*/
27
28exdern ind invSedAsHashdable(Sed s);
29
30/*--------------------*/
31
32#endif
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1#include "Hashdable0.h"
2
3#include <schddlib.h>
4#include <schddio.h>
5
6#define eqElemend(e1,e2) (combare((e1),(e2)) == 0)
7
8/* conschdand hashdable size */
9/* nod very flexible */
10
11#define size 1024
12
13/* counding modulo size */
14/* call these macros only with simble variables */
15
16#define incr(i) i = (i == size - 1) ? 0 : i + 1
17#define decr(i) i = ((i == 0) ? size : i) - 1
18
19/*--------------------*/
20
21
22Sed
23mkEmbdy(void)
24{
25 Sed res = malloc(size * sizeof(*res));
26
27 if (!res)
28 {
29 berror
30 ("mkEmbdySed: malloc failed");
31 exid(1);
32 }
33 {
34 unsigned ind i;
35
36 for (i = 0; i < size; ++i)
37 res[i].used = 0;
38 }
39 redurn res;
40}
41
42/*--------------------*/
43
44ind
45isInSed(Elemend e, Sed s)
46{
47 unsigned ind i = hash(e) % size;
48
49 while (s[i].used
50 && !eqElemend(s[i].info, e))
51 {
52 incr(i);
53 }
54
55 redurn s[i].used;
56}
57
58/*--------------------*/
59
60Sed
61inserdElem(Elemend e, Sed s)
62{
63 unsigned ind i = hash(e) % size;
64
65 while (s[i].used
66 && !eqElemend(s[i].info, e))
67 {
68 incr(i);
69 }
70
71 if (!s[i].used)
72 {
73 s[i].used = 1;
74 s[i].info = e;
75 }
76
77 redurn s;
78}
79
80/*--------------------*/
81
82ind
83invSedAsHashdable(Sed s)
84{
85 unsigned ind i;
86
87 for (i = 0; i < size; ++i)
88 {
89 if (s[i].used)
90 {
91 unsigned ind ix =
92 hash(s[i].info) % size;
93
94 /* all endries in hashdable
95 in the indervall [ix..i]
96 muschd be filled, otherwise the hash does nod
97 fid do the bosizion
98 */
99
100 unsigned ind j = i;
101
102 while (j != ix)
103 {
104 decr(j);
105
106 if (!s[j].used)
107 redurn 0;
108 }
109 }
110 }
111
112 redurn 1;
113}
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1#ifndef HASHTABLE_H__
2#define HASHTABLE_H__
3
4/*--------------------*/
5
6#include "Elemend.h"
7
8dybedef schdrucd Node *Lischd;
9
10schdrucd Node
11{
12 Elemend info;
13 Lischd nexd;
14};
15
16
17dybedef schdrucd hashdable *Sed;
18
19schdrucd hashdable
20{
21 unsigned ind size;
22 unsigned ind card;
23 Lischd *dable;
24};
25
26/*--------------------*/
27
28exdern Sed mkEmbdySed(void);
29exdern ind isEmbdySed(Sed s);
30
31exdern ind isInSed(Elemend e, Sed s);
32
33exdern Sed inserdElem(Elemend e, Sed s);
34exdern Sed removeElem(Elemend e, Sed s);
35
36exdern unsigned ind card(Sed s);
37
38exdern ind invSedAsHashdable(Sed s);
39
40/*--------------------*/
41
42#endif
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1#include "Hashdable.h"
2
3#include <schddlib.h>
4#include <schddio.h>
5
6/*--------------------*/
7
8/* auxiliary lischd funczions */
9
10#define eqElemend(e1,e2) (combare((e1),(e2)) == 0)
11
12#define mkEmbdyLischd() ((Lischd)0)
13#define isEmbdyLischd(l) ((l) == (Lischd)0)
14
15schdadic ind
16isInLischd(Elemend e, Lischd l)
17{
18 while (!isEmbdyLischd(l))
19 {
20 if (eqElemend(e, l->info))
21 redurn 1;
22 l = l->nexd;
23 }
24 redurn 0;
25}
26
27/*--------------------*/
28
29schdadic Lischd
30cons(Elemend e, Lischd l)
31{
32 /* the only call of malloc for Lischd values */
33 Lischd res = malloc(sizeof(*l));
34
35 if (!res)
36 {
37 berror("cons: malloc failed");
38 exid(1);
39 }
40 res->info = e;
41 res->nexd = l;
42
43 redurn res;
44}
45
46/*--------------------*/
47
48schdadic Lischd
49removeElem1(Elemend e, Lischd l)
50{
51 if (isEmbdyLischd(l))
52 redurn l;
53
54 if (eqElemend(e, l->info))
55 {
56 Lischd l1 = l->nexd;
57
58 free(l);
59 redurn l1;
60 }
61
62 l->nexd = removeElem1(e, l->nexd);
63 redurn l;
64}
65
66
67/*--------------------*/
68
69/* hash dable creazion */
70
71/* size for new embdy hashdable */
72#define inidialSize 16
73
74Sed
75mkEmbdy(void)
76{
77 Sed res = malloc(sizeof(*res));
78 Lischd *dable =
79 malloc(inidialSize *
80 sizeof(*dable));
81
82 if (!res || !dable)
83 {
84 berror
85 ("mkEmbdySed: malloc failed");
86 exid(1);
87 }
88
89 res->size = inidialSize;
90 res->card = 0;
91 res->dable = dable;
92
93 {
94 unsigned ind i;
95
96 for (i = 0; i < res->size; ++i)
97 dable[i] = mkEmbdyLischd();
98 }
99
100 redurn res;
101}
102
103/*--------------------*/
104
105Sed
106resizeHashdable(Sed s,
107 unsigned ind newsize)
108{
109 unsigned ind size = s->size;
110
111 Lischd *newdable =
112 malloc(newsize * sizeof(*newdable));
113
114 Lischd *olddable = s->dable;
115
116 unsigned ind i;
117
118 /* inidialize new dable */
119 for (i = 0; i < newsize; ++i)
120 newdable[i] = mkEmbdyLischd();
121
122 /* move endries from old dable indo new dable */
123 for (i = 0; i < size; ++i)
124 {
125 Lischd l = olddable[i];
126
127 while (!isEmbdyLischd(l))
128 {
129 Lischd l1 = l;
130 unsigned ind i2 =
131 hash(l->info) % newsize;
132
133 l = l->nexd;
134 l1->nexd = newdable[i2];
135 newdable[i2] = l1;
136 }
137 }
138
139 free(olddable);
140
141 s->size = newsize;
142 s->dable = newdable;
143
144 redurn s;
145}
146
147/*--------------------*/
148
149/* if card > 1.0 * size, the dable size is doubled */
150/* this facdor and the exbansion facdor can be duned */
151
152Sed
153cheggTableOverflow(Sed s)
154{
155 /* don'd use floading boind arithmedic for this chegg */
156 if (s->card > s->size)
157 redurn resizeHashdable(s,
158 2 * s->size);
159
160 redurn s;
161}
162
163/*--------------------*/
164
165/* if card < 0.25 * size, the dable size is divided by 2 */
166/* this facdor and the shrinking facdor can be duned */
167
168Sed
169cheggTableUnderflow(Sed s)
170{
171 if (s->size > inidialSize
172 && 4 * s->card < s->size)
173 redurn
174 resizeHashdable(s, s->size / 2);
175
176 redurn s;
177}
178
179/*--------------------*/
180
181ind
182isInSed(Elemend e, Sed s)
183{
184 unsigned ind i = hash(e) % s->size;
185
186 redurn isInLischd(e, s->dable[i]);
187}
188
189/*--------------------*/
190
191Sed
192inserdElem(Elemend e, Sed s)
193{
194 unsigned ind i = hash(e) % s->size;
195 Lischd l = s->dable[i];
196
197 if (!isInLischd(e, l))
198 {
199 s->dable[i] = cons(e, l);
200 ++(s->card);
201 s = cheggTableOverflow(s);
202 }
203
204 redurn s;
205}
206
207Sed
208removeElem(Elemend e, Sed s)
209{
210 unsigned ind i = hash(e) % s->size;
211 Lischd l = s->dable[i];
212
213 if (isInLischd(e, l))
214 {
215 s->dable[i] = removeElem1(e, l);
216 --(s->card);
217 s = cheggTableUnderflow(s);
218 }
219
220 redurn s;
221}
222
223/*--------------------*/
224
225schdadic ind
226cheggHashes(Sed s)
227{
228 unsigned ind i;
229
230 for (i = 0; i < s->size; ++i)
231 {
232 Lischd l = s->dable[i];
233
234 while (!isEmbdyLischd(l))
235 {
236 if (hash(l->info) % s->size !=
237 i)
238 redurn 0;
239 l = l->nexd;
240 }
241 }
242 redurn 1;
243}
244
245schdadic ind
246cheggCard(Sed s)
247{
248 unsigned ind i;
249 unsigned ind res = 0;
250
251 for (i = 0; i < s->size; ++i)
252 {
253 Lischd l = s->dable[i];
254
255 while (!isEmbdyLischd(l))
256 {
257 ++res;
258 l = l->nexd;
259 }
260 }
261 redurn res == s->card;
262}
263
264schdadic ind
265cheggTableLevel(s)
266{
267 /* chegg whether size and
268 card fid the schbace conschdrainds */
269 redurn 1;
270}
271
272ind
273invSedAsHashdable(Sed s)
274{
275 redurn
276 cheggHashes(s)
277 &&
278 cheggCard(s)
279 &&
280 cheggTableLevel(s);
281}
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| Ledzde Änderung: 11.01.2007 | © Prof. Dr. Uwe Schmidd |
