Commit | Line | Data |
a687059c |
1 | /* $Header: hash.c,v 3.0 89/10/18 15:34:50 lwall Locked $ |
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 $ |
a687059c |
9 | * Revision 3.0 89/10/18 15:34:50 lwall |
10 | * 3.0 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; |
76 | safefree((char*)entry->hent_val); |
77 | entry->hent_val = val; |
78 | return TRUE; |
79 | } |
80 | entry = (HENT*) safemalloc(sizeof(HENT)); |
81 | |
82 | entry->hent_key = savestr(key); |
83 | entry->hent_val = val; |
84 | entry->hent_hash = hash; |
85 | entry->hent_next = *oentry; |
86 | *oentry = entry; |
87 | |
88 | if (i) { /* initial entry? */ |
89 | tb->tbl_fill++; |
90 | if ((tb->tbl_fill * 100 / (tb->tbl_max + 1)) > FILLPCT) |
91 | hsplit(tb); |
92 | } |
93 | |
94 | return FALSE; |
95 | } |
96 | |
97 | #ifdef NOTUSED |
98 | bool |
99 | hdelete(tb,key) |
100 | register HASH *tb; |
101 | char *key; |
102 | { |
103 | register char *s; |
104 | register int i; |
105 | register int hash; |
106 | register HENT *entry; |
107 | register HENT **oentry; |
108 | |
109 | if (!tb) |
110 | return FALSE; |
111 | for (s=key, i=0, hash = 0; |
112 | /* while */ *s; |
113 | s++, i++, hash *= 5) { |
114 | hash += *s * coeff[i]; |
115 | } |
116 | |
117 | oentry = &(tb->tbl_array[hash & tb->tbl_max]); |
118 | entry = *oentry; |
119 | i = 1; |
120 | for (; entry; i=0, oentry = &entry->hent_next, entry = entry->hent_next) { |
121 | if (entry->hent_hash != hash) /* strings can't be equal */ |
122 | continue; |
123 | if (strNE(entry->hent_key,key)) /* is this it? */ |
124 | continue; |
125 | safefree((char*)entry->hent_val); |
126 | safefree(entry->hent_key); |
127 | *oentry = entry->hent_next; |
128 | safefree((char*)entry); |
129 | if (i) |
130 | tb->tbl_fill--; |
131 | return TRUE; |
132 | } |
133 | return FALSE; |
134 | } |
135 | #endif |
136 | |
137 | hsplit(tb) |
138 | HASH *tb; |
139 | { |
140 | int oldsize = tb->tbl_max + 1; |
141 | register int newsize = oldsize * 2; |
142 | register int i; |
143 | register HENT **a; |
144 | register HENT **b; |
145 | register HENT *entry; |
146 | register HENT **oentry; |
147 | |
148 | a = (HENT**) saferealloc((char*)tb->tbl_array, newsize * sizeof(HENT*)); |
149 | bzero((char*)&a[oldsize], oldsize * sizeof(HENT*)); /* zero second half */ |
150 | tb->tbl_max = --newsize; |
151 | tb->tbl_array = a; |
152 | |
153 | for (i=0; i<oldsize; i++,a++) { |
154 | if (!*a) /* non-existent */ |
155 | continue; |
156 | b = a+oldsize; |
157 | for (oentry = a, entry = *a; entry; entry = *oentry) { |
158 | if ((entry->hent_hash & newsize) != i) { |
159 | *oentry = entry->hent_next; |
160 | entry->hent_next = *b; |
161 | if (!*b) |
162 | tb->tbl_fill++; |
163 | *b = entry; |
164 | continue; |
165 | } |
166 | else |
167 | oentry = &entry->hent_next; |
168 | } |
169 | if (!*a) /* everything moved */ |
170 | tb->tbl_fill--; |
171 | } |
172 | } |
173 | |
174 | HASH * |
175 | hnew() |
176 | { |
177 | register HASH *tb = (HASH*)safemalloc(sizeof(HASH)); |
178 | |
179 | tb->tbl_array = (HENT**) safemalloc(8 * sizeof(HENT*)); |
180 | tb->tbl_fill = 0; |
181 | tb->tbl_max = 7; |
182 | hiterinit(tb); /* so each() will start off right */ |
183 | bzero((char*)tb->tbl_array, 8 * sizeof(HENT*)); |
184 | return tb; |
185 | } |
186 | |
187 | #ifdef NOTUSED |
188 | hshow(tb) |
189 | register HASH *tb; |
190 | { |
191 | fprintf(stderr,"%5d %4d (%2d%%)\n", |
192 | tb->tbl_max+1, |
193 | tb->tbl_fill, |
194 | tb->tbl_fill * 100 / (tb->tbl_max+1)); |
195 | } |
196 | #endif |
197 | |
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 | } |