Commit | Line | Data |
8d063cd8 |
1 | /* $Header: hash.c,v 1.0 87/12/18 13:05:17 root Exp $ |
2 | * |
3 | * $Log: hash.c,v $ |
4 | * Revision 1.0 87/12/18 13:05:17 root |
5 | * Initial revision |
6 | * |
7 | */ |
8 | |
9 | #include <stdio.h> |
10 | #include "EXTERN.h" |
11 | #include "handy.h" |
12 | #include "util.h" |
13 | #include "search.h" |
14 | #include "perl.h" |
15 | |
16 | STR * |
17 | hfetch(tb,key) |
18 | register HASH *tb; |
19 | char *key; |
20 | { |
21 | register char *s; |
22 | register int i; |
23 | register int hash; |
24 | register HENT *entry; |
25 | |
26 | if (!tb) |
27 | return Nullstr; |
28 | for (s=key, i=0, hash = 0; |
29 | /* while */ *s; |
30 | s++, i++, hash *= 5) { |
31 | hash += *s * coeff[i]; |
32 | } |
33 | entry = tb->tbl_array[hash & tb->tbl_max]; |
34 | for (; entry; entry = entry->hent_next) { |
35 | if (entry->hent_hash != hash) /* strings can't be equal */ |
36 | continue; |
37 | if (strNE(entry->hent_key,key)) /* is this it? */ |
38 | continue; |
39 | return entry->hent_val; |
40 | } |
41 | return Nullstr; |
42 | } |
43 | |
44 | bool |
45 | hstore(tb,key,val) |
46 | register HASH *tb; |
47 | char *key; |
48 | STR *val; |
49 | { |
50 | register char *s; |
51 | register int i; |
52 | register int hash; |
53 | register HENT *entry; |
54 | register HENT **oentry; |
55 | |
56 | if (!tb) |
57 | return FALSE; |
58 | for (s=key, i=0, hash = 0; |
59 | /* while */ *s; |
60 | s++, i++, hash *= 5) { |
61 | hash += *s * coeff[i]; |
62 | } |
63 | |
64 | oentry = &(tb->tbl_array[hash & tb->tbl_max]); |
65 | i = 1; |
66 | |
67 | for (entry = *oentry; entry; i=0, entry = entry->hent_next) { |
68 | if (entry->hent_hash != hash) /* strings can't be equal */ |
69 | continue; |
70 | if (strNE(entry->hent_key,key)) /* is this it? */ |
71 | continue; |
72 | safefree((char*)entry->hent_val); |
73 | entry->hent_val = val; |
74 | return TRUE; |
75 | } |
76 | entry = (HENT*) safemalloc(sizeof(HENT)); |
77 | |
78 | entry->hent_key = savestr(key); |
79 | entry->hent_val = val; |
80 | entry->hent_hash = hash; |
81 | entry->hent_next = *oentry; |
82 | *oentry = entry; |
83 | |
84 | if (i) { /* initial entry? */ |
85 | tb->tbl_fill++; |
86 | if ((tb->tbl_fill * 100 / (tb->tbl_max + 1)) > FILLPCT) |
87 | hsplit(tb); |
88 | } |
89 | |
90 | return FALSE; |
91 | } |
92 | |
93 | #ifdef NOTUSED |
94 | bool |
95 | hdelete(tb,key) |
96 | register HASH *tb; |
97 | char *key; |
98 | { |
99 | register char *s; |
100 | register int i; |
101 | register int hash; |
102 | register HENT *entry; |
103 | register HENT **oentry; |
104 | |
105 | if (!tb) |
106 | return FALSE; |
107 | for (s=key, i=0, hash = 0; |
108 | /* while */ *s; |
109 | s++, i++, hash *= 5) { |
110 | hash += *s * coeff[i]; |
111 | } |
112 | |
113 | oentry = &(tb->tbl_array[hash & tb->tbl_max]); |
114 | entry = *oentry; |
115 | i = 1; |
116 | for (; entry; i=0, oentry = &entry->hent_next, entry = entry->hent_next) { |
117 | if (entry->hent_hash != hash) /* strings can't be equal */ |
118 | continue; |
119 | if (strNE(entry->hent_key,key)) /* is this it? */ |
120 | continue; |
121 | safefree((char*)entry->hent_val); |
122 | safefree(entry->hent_key); |
123 | *oentry = entry->hent_next; |
124 | safefree((char*)entry); |
125 | if (i) |
126 | tb->tbl_fill--; |
127 | return TRUE; |
128 | } |
129 | return FALSE; |
130 | } |
131 | #endif |
132 | |
133 | hsplit(tb) |
134 | HASH *tb; |
135 | { |
136 | int oldsize = tb->tbl_max + 1; |
137 | register int newsize = oldsize * 2; |
138 | register int i; |
139 | register HENT **a; |
140 | register HENT **b; |
141 | register HENT *entry; |
142 | register HENT **oentry; |
143 | |
144 | a = (HENT**) saferealloc((char*)tb->tbl_array, newsize * sizeof(HENT*)); |
145 | bzero((char*)&a[oldsize], oldsize * sizeof(HENT*)); /* zero second half */ |
146 | tb->tbl_max = --newsize; |
147 | tb->tbl_array = a; |
148 | |
149 | for (i=0; i<oldsize; i++,a++) { |
150 | if (!*a) /* non-existent */ |
151 | continue; |
152 | b = a+oldsize; |
153 | for (oentry = a, entry = *a; entry; entry = *oentry) { |
154 | if ((entry->hent_hash & newsize) != i) { |
155 | *oentry = entry->hent_next; |
156 | entry->hent_next = *b; |
157 | if (!*b) |
158 | tb->tbl_fill++; |
159 | *b = entry; |
160 | continue; |
161 | } |
162 | else |
163 | oentry = &entry->hent_next; |
164 | } |
165 | if (!*a) /* everything moved */ |
166 | tb->tbl_fill--; |
167 | } |
168 | } |
169 | |
170 | HASH * |
171 | hnew() |
172 | { |
173 | register HASH *tb = (HASH*)safemalloc(sizeof(HASH)); |
174 | |
175 | tb->tbl_array = (HENT**) safemalloc(8 * sizeof(HENT*)); |
176 | tb->tbl_fill = 0; |
177 | tb->tbl_max = 7; |
178 | hiterinit(tb); /* so each() will start off right */ |
179 | bzero((char*)tb->tbl_array, 8 * sizeof(HENT*)); |
180 | return tb; |
181 | } |
182 | |
183 | #ifdef NOTUSED |
184 | hshow(tb) |
185 | register HASH *tb; |
186 | { |
187 | fprintf(stderr,"%5d %4d (%2d%%)\n", |
188 | tb->tbl_max+1, |
189 | tb->tbl_fill, |
190 | tb->tbl_fill * 100 / (tb->tbl_max+1)); |
191 | } |
192 | #endif |
193 | |
194 | hiterinit(tb) |
195 | register HASH *tb; |
196 | { |
197 | tb->tbl_riter = -1; |
198 | tb->tbl_eiter = Null(HENT*); |
199 | return tb->tbl_fill; |
200 | } |
201 | |
202 | HENT * |
203 | hiternext(tb) |
204 | register HASH *tb; |
205 | { |
206 | register HENT *entry; |
207 | |
208 | entry = tb->tbl_eiter; |
209 | do { |
210 | if (entry) |
211 | entry = entry->hent_next; |
212 | if (!entry) { |
213 | tb->tbl_riter++; |
214 | if (tb->tbl_riter > tb->tbl_max) { |
215 | tb->tbl_riter = -1; |
216 | break; |
217 | } |
218 | entry = tb->tbl_array[tb->tbl_riter]; |
219 | } |
220 | } while (!entry); |
221 | |
222 | tb->tbl_eiter = entry; |
223 | return entry; |
224 | } |
225 | |
226 | char * |
227 | hiterkey(entry) |
228 | register HENT *entry; |
229 | { |
230 | return entry->hent_key; |
231 | } |
232 | |
233 | STR * |
234 | hiterval(entry) |
235 | register HENT *entry; |
236 | { |
237 | return entry->hent_val; |
238 | } |