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