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1 | /* -*-c-*- |
2 | * |
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3 | * $Id: scan.c,v 1.5 2002/01/30 09:29:34 mdw Exp $ |
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4 | * |
5 | * Character scanners |
6 | * |
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7 | * (c) 1999 Straylight/Edgeware |
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8 | */ |
9 | |
10 | /*----- Licensing notice --------------------------------------------------* |
11 | * |
12 | * This file is part of the `fw' port forwarder. |
13 | * |
14 | * `fw' is free software; you can redistribute it and/or modify |
15 | * it under the terms of the GNU General Public License as published by |
16 | * the Free Software Foundation; either version 2 of the License, or |
17 | * (at your option) any later version. |
18 | * |
19 | * `fw' is distributed in the hope that it will be useful, |
20 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
21 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
22 | * GNU General Public License for more details. |
23 | * |
24 | * You should have received a copy of the GNU General Public License |
25 | * along with `fw'; if not, write to the Free Software Foundation, |
26 | * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. |
27 | */ |
28 | |
29 | /*----- Revision history --------------------------------------------------* |
30 | * |
31 | * $Log: scan.c,v $ |
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32 | * Revision 1.5 2002/01/30 09:29:34 mdw |
33 | * Initialize scanner properly. |
34 | * |
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35 | * Revision 1.4 2001/02/03 20:30:03 mdw |
36 | * Support re-reading config files on SIGHUP. |
37 | * |
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38 | * Revision 1.3 2000/08/01 17:58:10 mdw |
39 | * Fix subtleties with <ctype.h> functions. |
40 | * |
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41 | * Revision 1.2 1999/07/26 23:24:33 mdw |
42 | * Complete rewrite. Allow a list of character sources to enable changes |
43 | * during parsing of syntactic constructs. |
44 | * |
45 | * Revision 1.1.1.1 1999/07/01 08:56:23 mdw |
46 | * Initial revision. |
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47 | * |
48 | */ |
49 | |
50 | /*----- Header files ------------------------------------------------------*/ |
51 | |
52 | #include "config.h" |
53 | |
54 | #include <stdio.h> |
55 | #include <stdlib.h> |
56 | #include <string.h> |
57 | |
58 | #include <mLib/dstr.h> |
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59 | #include <mLib/sub.h> |
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60 | |
61 | #include "scan.h" |
62 | |
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63 | /*----- File scanner source -----------------------------------------------*/ |
64 | |
65 | /* --- File scanner block --- */ |
66 | |
67 | typedef struct fscan { |
68 | scansrc ss; |
69 | FILE *fp; |
70 | unsigned f; |
71 | } fscan; |
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72 | |
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73 | /* --- @scan@ --- */ |
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74 | |
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75 | static int fscan_scan(scansrc *ss) |
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76 | { |
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77 | fscan *fs = (fscan *)ss; |
78 | int ch = getc(fs->fp); |
79 | if (ch == '\n') |
80 | fs->ss.line++; |
81 | return (ch); |
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82 | } |
83 | |
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84 | /* --- @destroy@ --- */ |
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85 | |
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86 | static void fscan_destroy(scansrc *ss) |
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87 | { |
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88 | fscan *fs = (fscan *)ss; |
89 | if (!(fs->f & SCF_NOCLOSE)) |
90 | fclose(fs->fp); |
91 | if (fs->f & SCF_FREENAME) |
92 | free(fs->ss.src); |
93 | DESTROY(fs); |
94 | } |
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95 | |
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96 | /* --- File scanner operations --- */ |
97 | |
98 | static scansrc_ops fscan_ops = { fscan_scan, fscan_destroy }; |
99 | |
100 | /* --- @scan_file@ --- * |
101 | * |
102 | * Arguments: @FILE *fp@ = pointer to file descriptor |
103 | * @char *name@ = pointer to source file name |
104 | * @unsigned f@ = flags |
105 | * |
106 | * Returns: A scanner source. |
107 | * |
108 | * Use: Creates a new scanner source for reading from a file. |
109 | */ |
110 | |
111 | scansrc *scan_file(FILE *fp, char *name, unsigned f) |
112 | { |
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113 | fscan *fs = CREATE(fscan); |
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114 | fs->ss.ops = &fscan_ops; |
115 | fs->ss.src = name; |
116 | fs->ss.line = 1; |
117 | fs->fp = fp; |
118 | fs->f = f; |
119 | return (&fs->ss); |
120 | } |
121 | |
122 | /*---- Argv scanner source ------------------------------------------------*/ |
123 | |
124 | /* --- Argv scanner block --- */ |
125 | |
126 | typedef struct avscan { |
127 | scansrc ss; |
128 | char **av; |
129 | char *p; |
130 | } avscan; |
131 | |
132 | /* --- @scan@ --- */ |
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133 | |
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134 | static int avscan_scan(scansrc *ss) |
135 | { |
136 | avscan *as = (avscan *)ss; |
137 | int ch; |
138 | if (!as->p) |
139 | ch = EOF; |
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140 | else if ((ch = (unsigned char)*as->p++) == 0) { |
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141 | as->ss.line++; |
142 | as->p = *as->av++; |
143 | ch = '\n'; |
144 | } |
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145 | return (ch); |
146 | } |
147 | |
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148 | /* --- @destroy@ --- */ |
149 | |
150 | static void avscan_destroy(scansrc *ss) |
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151 | { |
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152 | avscan *as = (avscan *)ss; |
153 | DESTROY(as); |
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154 | } |
155 | |
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156 | /* --- Argv scanner operations --- */ |
157 | |
158 | static scansrc_ops avscan_ops = { avscan_scan, avscan_destroy }; |
159 | |
160 | /* --- @scan_argv@ --- * |
161 | * |
162 | * Arguments: @char **av@ = pointer to argument array (null terminated) |
163 | * |
164 | * Returns: A scanner source. |
165 | * |
166 | * Use: Creates a new scanner source for reading from an @argv@ |
167 | * array. |
168 | */ |
169 | |
170 | scansrc *scan_argv(char **av) |
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171 | { |
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172 | avscan *as = CREATE(avscan); |
173 | as->ss.ops = &avscan_ops; |
174 | as->ss.src = "<argv>"; |
175 | as->ss.line = 1; |
176 | as->p = *av++; |
177 | as->av = av; |
178 | return (&as->ss); |
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179 | } |
180 | |
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181 | /*----- End-of-file sentinel block ----------------------------------------*/ |
182 | |
183 | /* --- @scan@ --- */ |
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184 | |
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185 | static int eof_scan(scansrc *ss) |
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186 | { |
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187 | return (EOF); |
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188 | } |
189 | |
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190 | /* --- @destroy@ --- */ |
191 | |
192 | static void eof_destroy(scansrc *ss) |
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193 | { |
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194 | ; |
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195 | } |
196 | |
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197 | /* --- Eof scanner operations --- */ |
198 | |
199 | static scansrc_ops eof_ops = { eof_scan, eof_destroy }; |
200 | |
201 | /* --- The end of file marker --- */ |
202 | |
203 | static scansrc scan_eof = { &scan_eof, &eof_ops, "<eof>", 0, EOF }; |
204 | |
205 | /*----- General scanner handling ------------------------------------------*/ |
206 | |
207 | /* --- @scan@ --- * |
208 | * |
209 | * Arguments: @scanner *sc@ = pointer to main scanner context |
210 | * |
211 | * Returns: Character read, or end-of-file. |
212 | * |
213 | * Use: Scans a character from a source of characters. |
214 | */ |
215 | |
216 | int scan(scanner *sc) |
217 | { |
218 | int ch; |
219 | if (sc->head->pushback != EOF) { |
220 | ch = sc->head->pushback; |
221 | sc->head->pushback = EOF; |
222 | } else { |
223 | scansrc *ss = sc->head; |
224 | if (ss == &scan_eof) |
225 | ch = EOF; |
226 | else if ((ch = ss->ops->scan(ss)) == EOF) { |
227 | sc->head = ss->next; |
228 | if (sc->head == &scan_eof) |
229 | sc->tail = &sc->head; |
230 | ss->ops->destroy(ss); |
231 | ch = '\n'; |
232 | } |
233 | } |
234 | return (ch); |
235 | } |
236 | |
237 | /* --- @unscan@ --- * |
238 | * |
239 | * Arguments: @scanner *sc@ = pointer to main scanner context |
240 | * @int ch@ = character to unscan |
241 | * |
242 | * Returns: --- |
243 | * |
244 | * Use: Scans a character from a source of characters. |
245 | */ |
246 | |
247 | void unscan(scanner *sc, int ch) |
248 | { |
249 | sc->head->pushback = ch; |
250 | } |
251 | |
252 | /* --- @scan_push@ --- * |
253 | * |
254 | * Arguments: @scanner *sc@ = pointer to main scanner context |
255 | * @scansrc *ss@ = souorce to push |
256 | * |
257 | * Returns: --- |
258 | * |
259 | * Use: Pushes a scanner source onto the front of the queue. |
260 | */ |
261 | |
262 | void scan_push(scanner *sc, scansrc *ss) |
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263 | { |
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264 | ss->next = sc->head; |
265 | if (sc->head == &scan_eof) |
266 | sc->tail = &ss->next; |
267 | sc->head = ss; |
268 | ss->pushback = EOF; |
269 | ss->tok = 0; |
270 | ss->t = 0; |
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271 | } |
272 | |
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273 | /* --- @scan_add@ --- * |
274 | * |
275 | * Arguments: @scanner *sc@ = pointer to main scanner context |
276 | * @scansrc *ss@ = souorce to push |
277 | * |
278 | * Returns: --- |
279 | * |
280 | * Use: Adds a scanner source onto the end of the queue. |
281 | */ |
282 | |
283 | void scan_add(scanner *sc, scansrc *ss) |
284 | { |
285 | ss->next = &scan_eof; |
286 | *sc->tail = ss; |
287 | sc->tail = &ss->next; |
288 | ss->pushback = EOF; |
289 | ss->tok = 0; |
290 | ss->t = 0; |
291 | } |
292 | |
293 | /* --- @scan_create@ --- * |
294 | * |
295 | * Arguments: @scanner *sc@ = scanner context to initialize |
296 | * |
297 | * Returns: --- |
298 | * |
299 | * Use: Initializes a scanner block ready for use. |
300 | */ |
301 | |
302 | void scan_create(scanner *sc) |
303 | { |
304 | sc->head = &scan_eof; |
305 | sc->tail = &sc->head; |
306 | dstr_create(&sc->d); |
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307 | sc->wbegin = sc->wcont = 0; |
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308 | } |
309 | |
310 | /* --- @scan_destroy@ --- * |
311 | * |
312 | * Arguments: @scanner *sc@ = pointer to scanner context |
313 | * |
314 | * Returns: --- |
315 | * |
316 | * Use: Destroys a scanner and all the sources attached to it. |
317 | */ |
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318 | |
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319 | void scan_destroy(scanner *sc) |
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320 | { |
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321 | scansrc *ss = sc->head; |
322 | while (ss != &scan_eof) { |
323 | scansrc *sss = ss; |
324 | ss = ss->next; |
325 | if (sss->tok) |
326 | free(sss->tok); |
327 | sss->ops->destroy(sss); |
328 | } |
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329 | dstr_destroy(&sc->d); |
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330 | if (scan_eof.tok) |
331 | free(scan_eof.tok); |
332 | scan_eof.tok = 0; |
333 | sc->head = &scan_eof; |
334 | sc->tail = &sc->head; |
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335 | } |
336 | |
337 | /*----- That's all, folks -------------------------------------------------*/ |