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