1 /* Part of CPP library. (Macro hash table support.)
2 Copyright (C) 1986, 87, 89, 92-95, 1996 Free Software Foundation, Inc.
3 Written by Per Bothner, 1994.
4 Based on CCCP program by Paul Rubin, June 1986
5 Adapted to ANSI C, Richard Stallman, Jan 1987
7 This program is free software; you can redistribute it and/or modify it
8 under the terms of the GNU General Public License as published by the
9 Free Software Foundation; either version 2, or (at your option) any
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with this program; if not, write to the Free Software
19 Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
21 In other words, you are welcome to use, share and improve this program.
22 You are forbidden to forbid anyone else to use, share and improve
23 what you give them. Help stamp out software-hoarding! */
30 extern char *xmalloc PARAMS ((unsigned));
32 static HASHNODE *hashtab[HASHSIZE];
34 /* Return hash function on name. must be compatible with the one
35 computed a step at a time, elsewhere */
38 hashf (name, len, hashsize)
39 register const U_CHAR *name;
46 r = HASHSTEP (r, *name++);
48 return MAKE_POS (r) % hashsize;
51 /* Find the most recent hash node for name "name" (ending with first
52 non-identifier char) installed by install
54 If LEN is >= 0, it is the length of the name.
55 Otherwise, compute the length by scanning the entire name.
57 If HASH is >= 0, it is the precomputed hash code.
58 Otherwise, compute the hash code. */
61 cpp_lookup (pfile, name, len, hash)
62 cpp_reader *pfile ATTRIBUTE_UNUSED;
67 register const U_CHAR *bp;
68 register HASHNODE *bucket;
72 for (bp = name; is_idchar[*bp]; bp++) ;
77 hash = hashf (name, len, HASHSIZE);
79 bucket = hashtab[hash];
81 if (bucket->length == len && strncmp (bucket->name, name, len) == 0)
83 bucket = bucket->next;
85 return (HASHNODE *) 0;
89 * Delete a hash node. Some weirdness to free junk from macros.
90 * More such weirdness will have to be added if you define more hash
94 /* Note that the DEFINITION of a macro is removed from the hash table
95 but its storage is not freed. This would be a storage leak
96 except that it is not reasonable to keep undefining and redefining
97 large numbers of macros many times.
98 In any case, this is necessary, because a macro can be #undef'd
99 in the middle of reading the arguments to a call to it.
100 If #undef freed the DEFINITION, that would crash. */
107 if (hp->prev != NULL)
108 hp->prev->next = hp->next;
109 if (hp->next != NULL)
110 hp->next->prev = hp->prev;
112 /* make sure that the bucket chain header that
113 the deleted guy was on points to the right thing afterwards. */
114 if (hp == *hp->bucket_hdr)
115 *hp->bucket_hdr = hp->next;
117 if (hp->type == T_MACRO)
119 DEFINITION *d = hp->value.defn;
120 struct reflist *ap, *nextap;
122 for (ap = d->pattern; ap != NULL; ap = nextap)
128 free (d->args.argnames);
135 /* Install a name in the main hash table, even if it is already there.
136 name stops with first non alphanumeric, except leading '#'.
137 caller must check against redefinition if that is desired.
138 delete_macro () removes things installed by install () in fifo order.
139 this is important because of the `defined' special symbol used
140 in #if, and also if pushdef/popdef directives are ever implemented.
142 If LEN is >= 0, it is the length of the name.
143 Otherwise, compute the length by scanning the entire name.
145 If HASH is >= 0, it is the precomputed hash code.
146 Otherwise, compute the hash code. */
149 install (name, len, type, ivalue, value, hash)
157 register HASHNODE *hp;
158 register int i, bucket;
159 register U_CHAR *p, *q;
163 while (is_idchar[*p])
169 hash = hashf (name, len, HASHSIZE);
171 i = sizeof (HASHNODE) + len + 1;
172 hp = (HASHNODE *) xmalloc (i);
174 hp->bucket_hdr = &hashtab[bucket];
175 hp->next = hashtab[bucket];
176 hashtab[bucket] = hp;
178 if (hp->next != NULL)
182 if (hp->type == T_CONST)
183 hp->value.ival = ivalue;
185 hp->value.cpval = value;
186 hp->name = ((U_CHAR *) hp) + sizeof (HASHNODE);
189 for (i = 0; i < len; i++)
196 cpp_hash_cleanup (pfile)
197 cpp_reader *pfile ATTRIBUTE_UNUSED;
200 for (i = HASHSIZE; --i >= 0; )
203 delete_macro (hashtab[i]);