Commit | Line | Data |
79072805 |
1 | /* $RCSfile: hash.c,v $$Revision: 4.1 $$Date: 92/08/07 18:29:20 $ |
a687059c |
2 | * |
352d5a3a |
3 | * Copyright (c) 1991, Larry Wall |
a687059c |
4 | * |
352d5a3a |
5 | * You may distribute under the terms of either the GNU General Public |
6 | * License or the Artistic License, as specified in the README file. |
8d063cd8 |
7 | * |
8 | * $Log: hash.c,v $ |
8d063cd8 |
9 | */ |
10 | |
11 | #include <stdio.h> |
12 | #include "EXTERN.h" |
8d063cd8 |
13 | #include "a2p.h" |
9c8d0b29 |
14 | #include "util.h" |
8d063cd8 |
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; |
fe14fcc3 |
72 | /*NOSTRICT*/ |
9c8d0b29 |
73 | Safefree(entry->hent_val); |
8d063cd8 |
74 | entry->hent_val = val; |
75 | return TRUE; |
76 | } |
fe14fcc3 |
77 | /*NOSTRICT*/ |
8d063cd8 |
78 | entry = (HENT*) safemalloc(sizeof(HENT)); |
79 | |
80 | entry->hent_key = savestr(key); |
81 | entry->hent_val = val; |
82 | entry->hent_hash = hash; |
83 | entry->hent_next = *oentry; |
84 | *oentry = entry; |
85 | |
86 | if (i) { /* initial entry? */ |
87 | tb->tbl_fill++; |
88 | if ((tb->tbl_fill * 100 / (tb->tbl_max + 1)) > FILLPCT) |
89 | hsplit(tb); |
90 | } |
91 | |
92 | return FALSE; |
93 | } |
94 | |
95 | #ifdef NOTUSED |
96 | bool |
97 | hdelete(tb,key) |
98 | register HASH *tb; |
99 | char *key; |
100 | { |
101 | register char *s; |
102 | register int i; |
103 | register int hash; |
104 | register HENT *entry; |
105 | register HENT **oentry; |
106 | |
107 | if (!tb) |
108 | return FALSE; |
109 | for (s=key, i=0, hash = 0; |
110 | /* while */ *s; |
111 | s++, i++, hash *= 5) { |
112 | hash += *s * coeff[i]; |
113 | } |
114 | |
115 | oentry = &(tb->tbl_array[hash & tb->tbl_max]); |
116 | entry = *oentry; |
117 | i = 1; |
118 | for (; entry; i=0, oentry = &entry->hent_next, entry = entry->hent_next) { |
119 | if (entry->hent_hash != hash) /* strings can't be equal */ |
120 | continue; |
121 | if (strNE(entry->hent_key,key)) /* is this it? */ |
122 | continue; |
123 | safefree((char*)entry->hent_val); |
124 | safefree(entry->hent_key); |
125 | *oentry = entry->hent_next; |
126 | safefree((char*)entry); |
127 | if (i) |
128 | tb->tbl_fill--; |
129 | return TRUE; |
130 | } |
131 | return FALSE; |
132 | } |
133 | #endif |
134 | |
9c8d0b29 |
135 | void |
8d063cd8 |
136 | hsplit(tb) |
137 | HASH *tb; |
138 | { |
139 | int oldsize = tb->tbl_max + 1; |
140 | register int newsize = oldsize * 2; |
141 | register int i; |
142 | register HENT **a; |
143 | register HENT **b; |
144 | register HENT *entry; |
145 | register HENT **oentry; |
146 | |
147 | a = (HENT**) saferealloc((char*)tb->tbl_array, newsize * sizeof(HENT*)); |
148 | bzero((char*)&a[oldsize], oldsize * sizeof(HENT*)); /* zero second half */ |
149 | tb->tbl_max = --newsize; |
150 | tb->tbl_array = a; |
151 | |
152 | for (i=0; i<oldsize; i++,a++) { |
153 | if (!*a) /* non-existent */ |
154 | continue; |
155 | b = a+oldsize; |
156 | for (oentry = a, entry = *a; entry; entry = *oentry) { |
157 | if ((entry->hent_hash & newsize) != i) { |
158 | *oentry = entry->hent_next; |
159 | entry->hent_next = *b; |
160 | if (!*b) |
161 | tb->tbl_fill++; |
162 | *b = entry; |
163 | continue; |
164 | } |
165 | else |
166 | oentry = &entry->hent_next; |
167 | } |
168 | if (!*a) /* everything moved */ |
169 | tb->tbl_fill--; |
170 | } |
171 | } |
172 | |
173 | HASH * |
174 | hnew() |
175 | { |
176 | register HASH *tb = (HASH*)safemalloc(sizeof(HASH)); |
177 | |
178 | tb->tbl_array = (HENT**) safemalloc(8 * sizeof(HENT*)); |
179 | tb->tbl_fill = 0; |
180 | tb->tbl_max = 7; |
181 | hiterinit(tb); /* so each() will start off right */ |
182 | bzero((char*)tb->tbl_array, 8 * sizeof(HENT*)); |
183 | return tb; |
184 | } |
185 | |
186 | #ifdef NOTUSED |
187 | hshow(tb) |
188 | register HASH *tb; |
189 | { |
190 | fprintf(stderr,"%5d %4d (%2d%%)\n", |
191 | tb->tbl_max+1, |
192 | tb->tbl_fill, |
193 | tb->tbl_fill * 100 / (tb->tbl_max+1)); |
194 | } |
195 | #endif |
196 | |
9c8d0b29 |
197 | int |
8d063cd8 |
198 | hiterinit(tb) |
199 | register HASH *tb; |
200 | { |
201 | tb->tbl_riter = -1; |
202 | tb->tbl_eiter = Null(HENT*); |
203 | return tb->tbl_fill; |
204 | } |
205 | |
206 | HENT * |
207 | hiternext(tb) |
208 | register HASH *tb; |
209 | { |
210 | register HENT *entry; |
211 | |
212 | entry = tb->tbl_eiter; |
213 | do { |
214 | if (entry) |
215 | entry = entry->hent_next; |
216 | if (!entry) { |
217 | tb->tbl_riter++; |
218 | if (tb->tbl_riter > tb->tbl_max) { |
219 | tb->tbl_riter = -1; |
220 | break; |
221 | } |
222 | entry = tb->tbl_array[tb->tbl_riter]; |
223 | } |
224 | } while (!entry); |
225 | |
226 | tb->tbl_eiter = entry; |
227 | return entry; |
228 | } |
229 | |
230 | char * |
231 | hiterkey(entry) |
232 | register HENT *entry; |
233 | { |
234 | return entry->hent_key; |
235 | } |
236 | |
237 | STR * |
238 | hiterval(entry) |
239 | register HENT *entry; |
240 | { |
241 | return entry->hent_val; |
242 | } |