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fe14fcc3 | 1 | /* $Header: hash.c,v 4.0 91/03/20 01:57:49 lwall Locked $ |
a687059c LW |
2 | * |
3 | * Copyright (c) 1989, Larry Wall | |
4 | * | |
5 | * You may distribute under the terms of the GNU General Public License | |
6 | * as specified in the README file that comes with the perl 3.0 kit. | |
8d063cd8 LW |
7 | * |
8 | * $Log: hash.c,v $ | |
fe14fcc3 LW |
9 | * Revision 4.0 91/03/20 01:57:49 lwall |
10 | * 4.0 baseline. | |
8d063cd8 LW |
11 | * |
12 | */ | |
13 | ||
14 | #include <stdio.h> | |
15 | #include "EXTERN.h" | |
16 | #include "handy.h" | |
17 | #include "util.h" | |
18 | #include "a2p.h" | |
19 | ||
20 | STR * | |
21 | hfetch(tb,key) | |
22 | register HASH *tb; | |
23 | char *key; | |
24 | { | |
25 | register char *s; | |
26 | register int i; | |
27 | register int hash; | |
28 | register HENT *entry; | |
29 | ||
30 | if (!tb) | |
31 | return Nullstr; | |
32 | for (s=key, i=0, hash = 0; | |
33 | /* while */ *s; | |
34 | s++, i++, hash *= 5) { | |
35 | hash += *s * coeff[i]; | |
36 | } | |
37 | entry = tb->tbl_array[hash & tb->tbl_max]; | |
38 | for (; entry; entry = entry->hent_next) { | |
39 | if (entry->hent_hash != hash) /* strings can't be equal */ | |
40 | continue; | |
41 | if (strNE(entry->hent_key,key)) /* is this it? */ | |
42 | continue; | |
43 | return entry->hent_val; | |
44 | } | |
45 | return Nullstr; | |
46 | } | |
47 | ||
48 | bool | |
49 | hstore(tb,key,val) | |
50 | register HASH *tb; | |
51 | char *key; | |
52 | STR *val; | |
53 | { | |
54 | register char *s; | |
55 | register int i; | |
56 | register int hash; | |
57 | register HENT *entry; | |
58 | register HENT **oentry; | |
59 | ||
60 | if (!tb) | |
61 | return FALSE; | |
62 | for (s=key, i=0, hash = 0; | |
63 | /* while */ *s; | |
64 | s++, i++, hash *= 5) { | |
65 | hash += *s * coeff[i]; | |
66 | } | |
67 | ||
68 | oentry = &(tb->tbl_array[hash & tb->tbl_max]); | |
69 | i = 1; | |
70 | ||
71 | for (entry = *oentry; entry; i=0, entry = entry->hent_next) { | |
72 | if (entry->hent_hash != hash) /* strings can't be equal */ | |
73 | continue; | |
74 | if (strNE(entry->hent_key,key)) /* is this it? */ | |
75 | continue; | |
fe14fcc3 | 76 | /*NOSTRICT*/ |
8d063cd8 LW |
77 | safefree((char*)entry->hent_val); |
78 | entry->hent_val = val; | |
79 | return TRUE; | |
80 | } | |
fe14fcc3 | 81 | /*NOSTRICT*/ |
8d063cd8 LW |
82 | entry = (HENT*) safemalloc(sizeof(HENT)); |
83 | ||
84 | entry->hent_key = savestr(key); | |
85 | entry->hent_val = val; | |
86 | entry->hent_hash = hash; | |
87 | entry->hent_next = *oentry; | |
88 | *oentry = entry; | |
89 | ||
90 | if (i) { /* initial entry? */ | |
91 | tb->tbl_fill++; | |
92 | if ((tb->tbl_fill * 100 / (tb->tbl_max + 1)) > FILLPCT) | |
93 | hsplit(tb); | |
94 | } | |
95 | ||
96 | return FALSE; | |
97 | } | |
98 | ||
99 | #ifdef NOTUSED | |
100 | bool | |
101 | hdelete(tb,key) | |
102 | register HASH *tb; | |
103 | char *key; | |
104 | { | |
105 | register char *s; | |
106 | register int i; | |
107 | register int hash; | |
108 | register HENT *entry; | |
109 | register HENT **oentry; | |
110 | ||
111 | if (!tb) | |
112 | return FALSE; | |
113 | for (s=key, i=0, hash = 0; | |
114 | /* while */ *s; | |
115 | s++, i++, hash *= 5) { | |
116 | hash += *s * coeff[i]; | |
117 | } | |
118 | ||
119 | oentry = &(tb->tbl_array[hash & tb->tbl_max]); | |
120 | entry = *oentry; | |
121 | i = 1; | |
122 | for (; entry; i=0, oentry = &entry->hent_next, entry = entry->hent_next) { | |
123 | if (entry->hent_hash != hash) /* strings can't be equal */ | |
124 | continue; | |
125 | if (strNE(entry->hent_key,key)) /* is this it? */ | |
126 | continue; | |
127 | safefree((char*)entry->hent_val); | |
128 | safefree(entry->hent_key); | |
129 | *oentry = entry->hent_next; | |
130 | safefree((char*)entry); | |
131 | if (i) | |
132 | tb->tbl_fill--; | |
133 | return TRUE; | |
134 | } | |
135 | return FALSE; | |
136 | } | |
137 | #endif | |
138 | ||
139 | hsplit(tb) | |
140 | HASH *tb; | |
141 | { | |
142 | int oldsize = tb->tbl_max + 1; | |
143 | register int newsize = oldsize * 2; | |
144 | register int i; | |
145 | register HENT **a; | |
146 | register HENT **b; | |
147 | register HENT *entry; | |
148 | register HENT **oentry; | |
149 | ||
150 | a = (HENT**) saferealloc((char*)tb->tbl_array, newsize * sizeof(HENT*)); | |
151 | bzero((char*)&a[oldsize], oldsize * sizeof(HENT*)); /* zero second half */ | |
152 | tb->tbl_max = --newsize; | |
153 | tb->tbl_array = a; | |
154 | ||
155 | for (i=0; i<oldsize; i++,a++) { | |
156 | if (!*a) /* non-existent */ | |
157 | continue; | |
158 | b = a+oldsize; | |
159 | for (oentry = a, entry = *a; entry; entry = *oentry) { | |
160 | if ((entry->hent_hash & newsize) != i) { | |
161 | *oentry = entry->hent_next; | |
162 | entry->hent_next = *b; | |
163 | if (!*b) | |
164 | tb->tbl_fill++; | |
165 | *b = entry; | |
166 | continue; | |
167 | } | |
168 | else | |
169 | oentry = &entry->hent_next; | |
170 | } | |
171 | if (!*a) /* everything moved */ | |
172 | tb->tbl_fill--; | |
173 | } | |
174 | } | |
175 | ||
176 | HASH * | |
177 | hnew() | |
178 | { | |
179 | register HASH *tb = (HASH*)safemalloc(sizeof(HASH)); | |
180 | ||
181 | tb->tbl_array = (HENT**) safemalloc(8 * sizeof(HENT*)); | |
182 | tb->tbl_fill = 0; | |
183 | tb->tbl_max = 7; | |
184 | hiterinit(tb); /* so each() will start off right */ | |
185 | bzero((char*)tb->tbl_array, 8 * sizeof(HENT*)); | |
186 | return tb; | |
187 | } | |
188 | ||
189 | #ifdef NOTUSED | |
190 | hshow(tb) | |
191 | register HASH *tb; | |
192 | { | |
193 | fprintf(stderr,"%5d %4d (%2d%%)\n", | |
194 | tb->tbl_max+1, | |
195 | tb->tbl_fill, | |
196 | tb->tbl_fill * 100 / (tb->tbl_max+1)); | |
197 | } | |
198 | #endif | |
199 | ||
200 | hiterinit(tb) | |
201 | register HASH *tb; | |
202 | { | |
203 | tb->tbl_riter = -1; | |
204 | tb->tbl_eiter = Null(HENT*); | |
205 | return tb->tbl_fill; | |
206 | } | |
207 | ||
208 | HENT * | |
209 | hiternext(tb) | |
210 | register HASH *tb; | |
211 | { | |
212 | register HENT *entry; | |
213 | ||
214 | entry = tb->tbl_eiter; | |
215 | do { | |
216 | if (entry) | |
217 | entry = entry->hent_next; | |
218 | if (!entry) { | |
219 | tb->tbl_riter++; | |
220 | if (tb->tbl_riter > tb->tbl_max) { | |
221 | tb->tbl_riter = -1; | |
222 | break; | |
223 | } | |
224 | entry = tb->tbl_array[tb->tbl_riter]; | |
225 | } | |
226 | } while (!entry); | |
227 | ||
228 | tb->tbl_eiter = entry; | |
229 | return entry; | |
230 | } | |
231 | ||
232 | char * | |
233 | hiterkey(entry) | |
234 | register HENT *entry; | |
235 | { | |
236 | return entry->hent_key; | |
237 | } | |
238 | ||
239 | STR * | |
240 | hiterval(entry) | |
241 | register HENT *entry; | |
242 | { | |
243 | return entry->hent_val; | |
244 | } |