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1 | /* $RCSfile: hash.c,v $$Revision: 4.0.1.1 $$Date: 91/06/07 12:15:55 $ |
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2 | * |
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3 | * Copyright (c) 1991, Larry Wall |
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4 | * |
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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. |
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7 | * |
8 | * $Log: hash.c,v $ |
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9 | * Revision 4.0.1.1 91/06/07 12:15:55 lwall |
10 | * patch4: new copyright notice |
11 | * |
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12 | * Revision 4.0 91/03/20 01:57:49 lwall |
13 | * 4.0 baseline. |
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14 | * |
15 | */ |
16 | |
17 | #include <stdio.h> |
18 | #include "EXTERN.h" |
19 | #include "handy.h" |
20 | #include "util.h" |
21 | #include "a2p.h" |
22 | |
23 | STR * |
24 | hfetch(tb,key) |
25 | register HASH *tb; |
26 | char *key; |
27 | { |
28 | register char *s; |
29 | register int i; |
30 | register int hash; |
31 | register HENT *entry; |
32 | |
33 | if (!tb) |
34 | return Nullstr; |
35 | for (s=key, i=0, hash = 0; |
36 | /* while */ *s; |
37 | s++, i++, hash *= 5) { |
38 | hash += *s * coeff[i]; |
39 | } |
40 | entry = tb->tbl_array[hash & tb->tbl_max]; |
41 | for (; entry; entry = entry->hent_next) { |
42 | if (entry->hent_hash != hash) /* strings can't be equal */ |
43 | continue; |
44 | if (strNE(entry->hent_key,key)) /* is this it? */ |
45 | continue; |
46 | return entry->hent_val; |
47 | } |
48 | return Nullstr; |
49 | } |
50 | |
51 | bool |
52 | hstore(tb,key,val) |
53 | register HASH *tb; |
54 | char *key; |
55 | STR *val; |
56 | { |
57 | register char *s; |
58 | register int i; |
59 | register int hash; |
60 | register HENT *entry; |
61 | register HENT **oentry; |
62 | |
63 | if (!tb) |
64 | return FALSE; |
65 | for (s=key, i=0, hash = 0; |
66 | /* while */ *s; |
67 | s++, i++, hash *= 5) { |
68 | hash += *s * coeff[i]; |
69 | } |
70 | |
71 | oentry = &(tb->tbl_array[hash & tb->tbl_max]); |
72 | i = 1; |
73 | |
74 | for (entry = *oentry; entry; i=0, entry = entry->hent_next) { |
75 | if (entry->hent_hash != hash) /* strings can't be equal */ |
76 | continue; |
77 | if (strNE(entry->hent_key,key)) /* is this it? */ |
78 | continue; |
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79 | /*NOSTRICT*/ |
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80 | safefree((char*)entry->hent_val); |
81 | entry->hent_val = val; |
82 | return TRUE; |
83 | } |
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84 | /*NOSTRICT*/ |
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85 | entry = (HENT*) safemalloc(sizeof(HENT)); |
86 | |
87 | entry->hent_key = savestr(key); |
88 | entry->hent_val = val; |
89 | entry->hent_hash = hash; |
90 | entry->hent_next = *oentry; |
91 | *oentry = entry; |
92 | |
93 | if (i) { /* initial entry? */ |
94 | tb->tbl_fill++; |
95 | if ((tb->tbl_fill * 100 / (tb->tbl_max + 1)) > FILLPCT) |
96 | hsplit(tb); |
97 | } |
98 | |
99 | return FALSE; |
100 | } |
101 | |
102 | #ifdef NOTUSED |
103 | bool |
104 | hdelete(tb,key) |
105 | register HASH *tb; |
106 | char *key; |
107 | { |
108 | register char *s; |
109 | register int i; |
110 | register int hash; |
111 | register HENT *entry; |
112 | register HENT **oentry; |
113 | |
114 | if (!tb) |
115 | return FALSE; |
116 | for (s=key, i=0, hash = 0; |
117 | /* while */ *s; |
118 | s++, i++, hash *= 5) { |
119 | hash += *s * coeff[i]; |
120 | } |
121 | |
122 | oentry = &(tb->tbl_array[hash & tb->tbl_max]); |
123 | entry = *oentry; |
124 | i = 1; |
125 | for (; entry; i=0, oentry = &entry->hent_next, entry = entry->hent_next) { |
126 | if (entry->hent_hash != hash) /* strings can't be equal */ |
127 | continue; |
128 | if (strNE(entry->hent_key,key)) /* is this it? */ |
129 | continue; |
130 | safefree((char*)entry->hent_val); |
131 | safefree(entry->hent_key); |
132 | *oentry = entry->hent_next; |
133 | safefree((char*)entry); |
134 | if (i) |
135 | tb->tbl_fill--; |
136 | return TRUE; |
137 | } |
138 | return FALSE; |
139 | } |
140 | #endif |
141 | |
142 | hsplit(tb) |
143 | HASH *tb; |
144 | { |
145 | int oldsize = tb->tbl_max + 1; |
146 | register int newsize = oldsize * 2; |
147 | register int i; |
148 | register HENT **a; |
149 | register HENT **b; |
150 | register HENT *entry; |
151 | register HENT **oentry; |
152 | |
153 | a = (HENT**) saferealloc((char*)tb->tbl_array, newsize * sizeof(HENT*)); |
154 | bzero((char*)&a[oldsize], oldsize * sizeof(HENT*)); /* zero second half */ |
155 | tb->tbl_max = --newsize; |
156 | tb->tbl_array = a; |
157 | |
158 | for (i=0; i<oldsize; i++,a++) { |
159 | if (!*a) /* non-existent */ |
160 | continue; |
161 | b = a+oldsize; |
162 | for (oentry = a, entry = *a; entry; entry = *oentry) { |
163 | if ((entry->hent_hash & newsize) != i) { |
164 | *oentry = entry->hent_next; |
165 | entry->hent_next = *b; |
166 | if (!*b) |
167 | tb->tbl_fill++; |
168 | *b = entry; |
169 | continue; |
170 | } |
171 | else |
172 | oentry = &entry->hent_next; |
173 | } |
174 | if (!*a) /* everything moved */ |
175 | tb->tbl_fill--; |
176 | } |
177 | } |
178 | |
179 | HASH * |
180 | hnew() |
181 | { |
182 | register HASH *tb = (HASH*)safemalloc(sizeof(HASH)); |
183 | |
184 | tb->tbl_array = (HENT**) safemalloc(8 * sizeof(HENT*)); |
185 | tb->tbl_fill = 0; |
186 | tb->tbl_max = 7; |
187 | hiterinit(tb); /* so each() will start off right */ |
188 | bzero((char*)tb->tbl_array, 8 * sizeof(HENT*)); |
189 | return tb; |
190 | } |
191 | |
192 | #ifdef NOTUSED |
193 | hshow(tb) |
194 | register HASH *tb; |
195 | { |
196 | fprintf(stderr,"%5d %4d (%2d%%)\n", |
197 | tb->tbl_max+1, |
198 | tb->tbl_fill, |
199 | tb->tbl_fill * 100 / (tb->tbl_max+1)); |
200 | } |
201 | #endif |
202 | |
203 | hiterinit(tb) |
204 | register HASH *tb; |
205 | { |
206 | tb->tbl_riter = -1; |
207 | tb->tbl_eiter = Null(HENT*); |
208 | return tb->tbl_fill; |
209 | } |
210 | |
211 | HENT * |
212 | hiternext(tb) |
213 | register HASH *tb; |
214 | { |
215 | register HENT *entry; |
216 | |
217 | entry = tb->tbl_eiter; |
218 | do { |
219 | if (entry) |
220 | entry = entry->hent_next; |
221 | if (!entry) { |
222 | tb->tbl_riter++; |
223 | if (tb->tbl_riter > tb->tbl_max) { |
224 | tb->tbl_riter = -1; |
225 | break; |
226 | } |
227 | entry = tb->tbl_array[tb->tbl_riter]; |
228 | } |
229 | } while (!entry); |
230 | |
231 | tb->tbl_eiter = entry; |
232 | return entry; |
233 | } |
234 | |
235 | char * |
236 | hiterkey(entry) |
237 | register HENT *entry; |
238 | { |
239 | return entry->hent_key; |
240 | } |
241 | |
242 | STR * |
243 | hiterval(entry) |
244 | register HENT *entry; |
245 | { |
246 | return entry->hent_val; |
247 | } |