1 /* Part of CPP library. (Macro hash table support.)
2 Copyright (C) 1986, 87, 89, 92, 93, 94, 1995 Free Software Foundation, Inc.
3 Written by Per Bothner, 1994.
4 Based on CCCP program by 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! */
27 extern char *xmalloc PARAMS ((unsigned));
29 /* Define a generic NULL if one hasn't already been defined. */
41 * return hash function on name. must be compatible with the one
42 * computed a step at a time, elsewhere
46 register const U_CHAR *name,
53 r = HASHSTEP (r, *name++);
55 return MAKE_POS (r) % hashsize;
59 * find the most recent hash node for name name (ending with first
60 * non-identifier char) installed by install
62 * If LEN is >= 0, it is the length of the name.
63 * Otherwise, compute the length by scanning the entire name.
65 * If HASH is >= 0, it is the precomputed hash code.
66 * Otherwise, compute the hash code.
70 struct parse_file *pfile,
75 register const U_CHAR *bp;
76 register HASHNODE *bucket;
80 for (bp = name; is_idchar[*bp]; bp++) ;
85 hash = hashf (name, len, HASHSIZE);
87 bucket = hashtab[hash];
89 if (bucket->length == len && strncmp (bucket->name, name, len) == 0)
91 bucket = bucket->next;
97 * Delete a hash node. Some weirdness to free junk from macros.
98 * More such weirdness will have to be added if you define more hash
102 /* Note that the DEFINITION of a macro is removed from the hash table
103 but its storage is not freed. This would be a storage leak
104 except that it is not reasonable to keep undefining and redefining
105 large numbers of macros many times.
106 In any case, this is necessary, because a macro can be #undef'd
107 in the middle of reading the arguments to a call to it.
108 If #undef freed the DEFINITION, that would crash. */
115 if (hp->prev != NULL)
116 hp->prev->next = hp->next;
117 if (hp->next != NULL)
118 hp->next->prev = hp->prev;
120 /* make sure that the bucket chain header that
121 the deleted guy was on points to the right thing afterwards. */
122 if (hp == *hp->bucket_hdr)
123 *hp->bucket_hdr = hp->next;
125 if (hp->type == T_MACRO)
127 DEFINITION *d = hp->value.defn;
128 struct reflist *ap, *nextap;
130 for (ap = d->pattern; ap != NULL; ap = nextap)
136 free (d->args.argnames);
143 * install a name in the main hash table, even if it is already there.
144 * name stops with first non alphanumeric, except leading '#'.
145 * caller must check against redefinition if that is desired.
146 * delete_macro () removes things installed by install () in fifo order.
147 * this is important because of the `defined' special symbol used
148 * in #if, and also if pushdef/popdef directives are ever implemented.
150 * If LEN is >= 0, it is the length of the name.
151 * Otherwise, compute the length by scanning the entire name.
153 * If HASH is >= 0, it is the precomputed hash code.
154 * Otherwise, compute the hash code.
165 register HASHNODE *hp;
166 register int i, bucket;
167 register U_CHAR *p, *q;
171 while (is_idchar[*p])
177 hash = hashf (name, len, HASHSIZE);
179 i = sizeof (HASHNODE) + len + 1;
180 hp = (HASHNODE *) xmalloc (i);
182 hp->bucket_hdr = &hashtab[bucket];
183 hp->next = hashtab[bucket];
184 hashtab[bucket] = hp;
186 if (hp->next != NULL)
190 if (hp->type == T_CONST)
191 hp->value.ival = ivalue;
193 hp->value.cpval = value;
194 hp->name = ((U_CHAR *) hp) + sizeof (HASHNODE);
197 for (i = 0; i < len; i++)
208 for (i = HASHSIZE; --i >= 0; )
211 delete_macro (hashtab[i]);