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1.1 misho 1: /*
2: * Copyright (C) 2004, 2005, 2007 Internet Systems Consortium, Inc. ("ISC")
3: * Copyright (C) 1996-2001 Internet Software Consortium.
4: *
5: * Permission to use, copy, modify, and/or distribute this software for any
6: * purpose with or without fee is hereby granted, provided that the above
7: * copyright notice and this permission notice appear in all copies.
8: *
9: * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
10: * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
11: * AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
12: * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
13: * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
14: * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
15: * PERFORMANCE OF THIS SOFTWARE.
16: */
17:
18: /* $Id: symtab.c,v 1.30 2007/06/19 23:47:17 tbox Exp $ */
19:
20: /*! \file */
21:
22: #include <config.h>
23:
24: #include <ctype.h>
25:
26: #include <isc/magic.h>
27: #include <isc/mem.h>
28: #include <isc/string.h>
29: #include <isc/symtab.h>
30: #include <isc/util.h>
31:
32: typedef struct elt {
33: char * key;
34: unsigned int type;
35: isc_symvalue_t value;
36: LINK(struct elt) link;
37: } elt_t;
38:
39: typedef LIST(elt_t) eltlist_t;
40:
41: #define SYMTAB_MAGIC ISC_MAGIC('S', 'y', 'm', 'T')
42: #define VALID_SYMTAB(st) ISC_MAGIC_VALID(st, SYMTAB_MAGIC)
43:
44: struct isc_symtab {
45: /* Unlocked. */
46: unsigned int magic;
47: isc_mem_t * mctx;
48: unsigned int size;
49: eltlist_t * table;
50: isc_symtabaction_t undefine_action;
51: void * undefine_arg;
52: isc_boolean_t case_sensitive;
53: };
54:
55: isc_result_t
56: isc_symtab_create(isc_mem_t *mctx, unsigned int size,
57: isc_symtabaction_t undefine_action,
58: void *undefine_arg,
59: isc_boolean_t case_sensitive,
60: isc_symtab_t **symtabp)
61: {
62: isc_symtab_t *symtab;
63: unsigned int i;
64:
65: REQUIRE(mctx != NULL);
66: REQUIRE(symtabp != NULL && *symtabp == NULL);
67: REQUIRE(size > 0); /* Should be prime. */
68:
69: symtab = (isc_symtab_t *)isc_mem_get(mctx, sizeof(*symtab));
70: if (symtab == NULL)
71: return (ISC_R_NOMEMORY);
72: symtab->table = (eltlist_t *)isc_mem_get(mctx,
73: size * sizeof(eltlist_t));
74: if (symtab->table == NULL) {
75: isc_mem_put(mctx, symtab, sizeof(*symtab));
76: return (ISC_R_NOMEMORY);
77: }
78: for (i = 0; i < size; i++)
79: INIT_LIST(symtab->table[i]);
80: symtab->mctx = mctx;
81: symtab->size = size;
82: symtab->undefine_action = undefine_action;
83: symtab->undefine_arg = undefine_arg;
84: symtab->case_sensitive = case_sensitive;
85: symtab->magic = SYMTAB_MAGIC;
86:
87: *symtabp = symtab;
88:
89: return (ISC_R_SUCCESS);
90: }
91:
92: void
93: isc_symtab_destroy(isc_symtab_t **symtabp) {
94: isc_symtab_t *symtab;
95: unsigned int i;
96: elt_t *elt, *nelt;
97:
98: REQUIRE(symtabp != NULL);
99: symtab = *symtabp;
100: REQUIRE(VALID_SYMTAB(symtab));
101:
102: for (i = 0; i < symtab->size; i++) {
103: for (elt = HEAD(symtab->table[i]); elt != NULL; elt = nelt) {
104: nelt = NEXT(elt, link);
105: if (symtab->undefine_action != NULL)
106: (symtab->undefine_action)(elt->key,
107: elt->type,
108: elt->value,
109: symtab->undefine_arg);
110: isc_mem_put(symtab->mctx, elt, sizeof(*elt));
111: }
112: }
113: isc_mem_put(symtab->mctx, symtab->table,
114: symtab->size * sizeof(eltlist_t));
115: symtab->magic = 0;
116: isc_mem_put(symtab->mctx, symtab, sizeof(*symtab));
117:
118: *symtabp = NULL;
119: }
120:
121: static inline unsigned int
122: hash(const char *key, isc_boolean_t case_sensitive) {
123: const char *s;
124: unsigned int h = 0;
125: int c;
126:
127: /*
128: * This hash function is similar to the one Ousterhout
129: * uses in Tcl.
130: */
131:
132: if (case_sensitive) {
133: for (s = key; *s != '\0'; s++) {
134: h += (h << 3) + *s;
135: }
136: } else {
137: for (s = key; *s != '\0'; s++) {
138: c = *s;
139: c = tolower((unsigned char)c);
140: h += (h << 3) + c;
141: }
142: }
143:
144: return (h);
145: }
146:
147: #define FIND(s, k, t, b, e) \
148: b = hash((k), (s)->case_sensitive) % (s)->size; \
149: if ((s)->case_sensitive) { \
150: for (e = HEAD((s)->table[b]); e != NULL; e = NEXT(e, link)) { \
151: if (((t) == 0 || e->type == (t)) && \
152: strcmp(e->key, (k)) == 0) \
153: break; \
154: } \
155: } else { \
156: for (e = HEAD((s)->table[b]); e != NULL; e = NEXT(e, link)) { \
157: if (((t) == 0 || e->type == (t)) && \
158: strcasecmp(e->key, (k)) == 0) \
159: break; \
160: } \
161: }
162:
163: isc_result_t
164: isc_symtab_lookup(isc_symtab_t *symtab, const char *key, unsigned int type,
165: isc_symvalue_t *value)
166: {
167: unsigned int bucket;
168: elt_t *elt;
169:
170: REQUIRE(VALID_SYMTAB(symtab));
171: REQUIRE(key != NULL);
172:
173: FIND(symtab, key, type, bucket, elt);
174:
175: if (elt == NULL)
176: return (ISC_R_NOTFOUND);
177:
178: if (value != NULL)
179: *value = elt->value;
180:
181: return (ISC_R_SUCCESS);
182: }
183:
184: isc_result_t
185: isc_symtab_define(isc_symtab_t *symtab, const char *key, unsigned int type,
186: isc_symvalue_t value, isc_symexists_t exists_policy)
187: {
188: unsigned int bucket;
189: elt_t *elt;
190:
191: REQUIRE(VALID_SYMTAB(symtab));
192: REQUIRE(key != NULL);
193: REQUIRE(type != 0);
194:
195: FIND(symtab, key, type, bucket, elt);
196:
197: if (exists_policy != isc_symexists_add && elt != NULL) {
198: if (exists_policy == isc_symexists_reject)
199: return (ISC_R_EXISTS);
200: INSIST(exists_policy == isc_symexists_replace);
201: UNLINK(symtab->table[bucket], elt, link);
202: if (symtab->undefine_action != NULL)
203: (symtab->undefine_action)(elt->key, elt->type,
204: elt->value,
205: symtab->undefine_arg);
206: } else {
207: elt = (elt_t *)isc_mem_get(symtab->mctx, sizeof(*elt));
208: if (elt == NULL)
209: return (ISC_R_NOMEMORY);
210: ISC_LINK_INIT(elt, link);
211: }
212:
213: /*
214: * Though the "key" can be const coming in, it is not stored as const
215: * so that the calling program can easily have writable access to
216: * it in its undefine_action function. In the event that it *was*
217: * truly const coming in and then the caller modified it anyway ...
218: * well, don't do that!
219: */
220: DE_CONST(key, elt->key);
221: elt->type = type;
222: elt->value = value;
223:
224: /*
225: * We prepend so that the most recent definition will be found.
226: */
227: PREPEND(symtab->table[bucket], elt, link);
228:
229: return (ISC_R_SUCCESS);
230: }
231:
232: isc_result_t
233: isc_symtab_undefine(isc_symtab_t *symtab, const char *key, unsigned int type) {
234: unsigned int bucket;
235: elt_t *elt;
236:
237: REQUIRE(VALID_SYMTAB(symtab));
238: REQUIRE(key != NULL);
239:
240: FIND(symtab, key, type, bucket, elt);
241:
242: if (elt == NULL)
243: return (ISC_R_NOTFOUND);
244:
245: if (symtab->undefine_action != NULL)
246: (symtab->undefine_action)(elt->key, elt->type,
247: elt->value, symtab->undefine_arg);
248: UNLINK(symtab->table[bucket], elt, link);
249: isc_mem_put(symtab->mctx, elt, sizeof(*elt));
250:
251: return (ISC_R_SUCCESS);
252: }