1 /* sym - symbol table routines */
2
3 /* Copyright (c) 1990 The Regents of the University of California. */
4 /* All rights reserved. */
5
6 /* This code is derived from software contributed to Berkeley by */
7 /* Vern Paxson. */
8
9 /* The United States Government has rights in this work pursuant */
10 /* to contract no. DE-AC03-76SF00098 between the United States */
11 /* Department of Energy and the University of California. */
12
13 /* This file is part of flex. */
14
15 /* Redistribution and use in source and binary forms, with or without */
16 /* modification, are permitted provided that the following conditions */
17 /* are met: */
18
19 /* 1. Redistributions of source code must retain the above copyright */
20 /* notice, this list of conditions and the following disclaimer. */
21 /* 2. Redistributions in binary form must reproduce the above copyright */
22 /* notice, this list of conditions and the following disclaimer in the */
23 /* documentation and/or other materials provided with the distribution. */
24
25 /* Neither the name of the University nor the names of its contributors */
26 /* may be used to endorse or promote products derived from this software */
27 /* without specific prior written permission. */
28
29 /* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR */
30 /* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED */
31 /* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR */
32 /* PURPOSE. */
33
34 #include "flexdef.h"
35
36 /* Variables for symbol tables:
37 * sctbl - start-condition symbol table
38 * ndtbl - name-definition symbol table
39 * ccltab - character class text symbol table
40 */
41
42 struct hash_entry {
43 struct hash_entry *prev, *next;
44 char *name;
45 char *str_val;
46 int int_val;
47 };
48
49 typedef struct hash_entry **hash_table;
50
51 #define NAME_TABLE_HASH_SIZE 101
52 #define START_COND_HASH_SIZE 101
53 #define CCL_HASH_SIZE 101
54
55 static struct hash_entry *ndtbl[NAME_TABLE_HASH_SIZE];
56 static struct hash_entry *sctbl[START_COND_HASH_SIZE];
57 static struct hash_entry *ccltab[CCL_HASH_SIZE];
58
59
60 /* declare functions that have forward references */
61
62 static int addsym(char[], char *, int, hash_table, int);
63 static struct hash_entry *findsym (const char *sym, hash_table table,
64 int table_size);
65 static int hashfunct(const char *, int);
66
67
68 /* addsym - add symbol and definitions to symbol table
69 *
70 * -1 is returned if the symbol already exists, and the change not made.
71 */
72
73 static int addsym (char sym[], char *str_def, int int_def, hash_table table, int table_size)
74 {
75 int hash_val = hashfunct (sym, table_size);
76 struct hash_entry *sym_entry = table[hash_val];
77 struct hash_entry *new_entry;
78 struct hash_entry *successor;
79
80 while (sym_entry) {
81 if (!strcmp (sym, sym_entry->name)) { /* entry already exists */
82 return -1;
83 }
84
85 sym_entry = sym_entry->next;
86 }
87
88 /* create new entry */
89 new_entry = malloc(sizeof(struct hash_entry));
90
91 if (new_entry == NULL)
92 flexfatal (_("symbol table memory allocation failed"));
93
94 if ((successor = table[hash_val]) != 0) {
95 new_entry->next = successor;
96 successor->prev = new_entry;
97 }
98 else
99 new_entry->next = NULL;
100
101 new_entry->prev = NULL;
102 new_entry->name = sym;
103 new_entry->str_val = str_def;
104 new_entry->int_val = int_def;
105
106 table[hash_val] = new_entry;
107
108 return 0;
109 }
110
111
112 /* cclinstal - save the text of a character class */
113
114 void cclinstal (char ccltxt[], int cclnum)
115 {
116 /* We don't bother checking the return status because we are not
117 * called unless the symbol is new.
118 */
119
120 (void) addsym (xstrdup(ccltxt),
121 (char *) 0, cclnum, ccltab, CCL_HASH_SIZE);
122 }
123
124
125 /* ccllookup - lookup the number associated with character class text
126 *
127 * Returns 0 if there's no CCL associated with the text.
128 */
129
130 int ccllookup (char ccltxt[])
131 {
132 return findsym (ccltxt, ccltab, CCL_HASH_SIZE)->int_val;
133 }
134
135
136 /* findsym - find symbol in symbol table */
137
138 static struct hash_entry *findsym (const char *sym, hash_table table, int table_size)
139 {
140 static struct hash_entry empty_entry = {
141 NULL, NULL, NULL, NULL, 0,
142 };
143 struct hash_entry *sym_entry =
144
145 table[hashfunct (sym, table_size)];
146
147 while (sym_entry) {
148 if (!strcmp (sym, sym_entry->name))
149 return sym_entry;
150 sym_entry = sym_entry->next;
151 }
152
153 return &empty_entry;
154 }
155
156 /* hashfunct - compute the hash value for "str" and hash size "hash_size" */
157
158 static int hashfunct (const char *str, int hash_size)
159 {
160 int hashval;
161 int locstr;
162
163 hashval = 0;
164 locstr = 0;
165
166 while (str[locstr]) {
167 hashval = (hashval << 1) + (unsigned char) str[locstr++];
168 hashval %= hash_size;
169 }
170
171 return hashval;
172 }
173
174
175 /* ndinstal - install a name definition */
176
177 void ndinstal (const char *name, char definition[])
178 {
179
180 if (addsym (xstrdup(name),
181 xstrdup(definition), 0,
182 ndtbl, NAME_TABLE_HASH_SIZE))
183 synerr (_("name defined twice"));
184 }
185
186
187 /* ndlookup - lookup a name definition
188 *
189 * Returns a nil pointer if the name definition does not exist.
190 */
191
192 char *ndlookup (const char *nd)
193 {
194 return findsym (nd, ndtbl, NAME_TABLE_HASH_SIZE)->str_val;
195 }
196
197
198 /* scextend - increase the maximum number of start conditions */
199
200 void scextend (void)
201 {
202 current_max_scs += MAX_SCS_INCREMENT;
203
204 ++num_reallocs;
205
206 scset = reallocate_integer_array (scset, current_max_scs);
207 scbol = reallocate_integer_array (scbol, current_max_scs);
208 scxclu = reallocate_integer_array (scxclu, current_max_scs);
209 sceof = reallocate_integer_array (sceof, current_max_scs);
210 scname = reallocate_char_ptr_array (scname, current_max_scs);
211 }
212
213
214 /* scinstal - make a start condition
215 *
216 * NOTE
217 * The start condition is "exclusive" if xcluflg is true.
218 */
219
220 void scinstal (const char *str, int xcluflg)
221 {
222
223 if (++lastsc >= current_max_scs)
224 scextend ();
225
226 scname[lastsc] = xstrdup(str);
227
228 if (addsym(scname[lastsc], NULL, lastsc,
229 sctbl, START_COND_HASH_SIZE))
230 format_pinpoint_message (_
231 ("start condition %s declared twice"),
232 str);
233
234 scset[lastsc] = mkstate (SYM_EPSILON);
235 scbol[lastsc] = mkstate (SYM_EPSILON);
236 scxclu[lastsc] = xcluflg;
237 sceof[lastsc] = false;
238 }
239
240
241 /* sclookup - lookup the number associated with a start condition
242 *
243 * Returns 0 if no such start condition.
244 */
245
246 int sclookup (const char *str)
247 {
248 return findsym (str, sctbl, START_COND_HASH_SIZE)->int_val;
249 }