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