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1 | /* $Header: hash.c,v 4.0 91/03/20 01:57:49 lwall Locked $ |
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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. |
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7 | * |
8 | * $Log: hash.c,v $ |
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9 | * Revision 4.0 91/03/20 01:57:49 lwall |
10 | * 4.0 baseline. |
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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; |
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76 | /*NOSTRICT*/ |
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77 | safefree((char*)entry->hent_val); |
78 | entry->hent_val = val; |
79 | return TRUE; |
80 | } |
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81 | /*NOSTRICT*/ |
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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 | } |