3 * $Id: scan.c,v 1.6 2002/02/22 23:44:16 mdw Exp $
7 * (c) 1999 Straylight/Edgeware
10 /*----- Licensing notice --------------------------------------------------*
12 * This file is part of the `fw' port forwarder.
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.
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.
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.
29 /*----- Revision history --------------------------------------------------*
32 * Revision 1.6 2002/02/22 23:44:16 mdw
33 * Miscellaneous tidying up, to make this code independent of `fw'. It
34 * might end up in a library somewhere.
36 * Revision 1.5 2002/01/30 09:29:34 mdw
37 * Initialize scanner properly.
39 * Revision 1.4 2001/02/03 20:30:03 mdw
40 * Support re-reading config files on SIGHUP.
42 * Revision 1.3 2000/08/01 17:58:10 mdw
43 * Fix subtleties with <ctype.h> functions.
45 * Revision 1.2 1999/07/26 23:24:33 mdw
46 * Complete rewrite. Allow a list of character sources to enable changes
47 * during parsing of syntactic constructs.
49 * Revision 1.1.1.1 1999/07/01 08:56:23 mdw
54 /*----- Header files ------------------------------------------------------*/
60 #include <mLib/dstr.h>
65 /*----- File scanner source -----------------------------------------------*/
67 /* --- File scanner block --- */
69 typedef struct fscan {
77 static int fscan_scan(scansrc *ss)
79 fscan *fs = (fscan *)ss;
80 int ch = getc(fs->fp);
86 /* --- @destroy@ --- */
88 static void fscan_destroy(scansrc *ss)
90 fscan *fs = (fscan *)ss;
91 if (!(fs->f & SCF_NOCLOSE))
97 /* --- File scanner operations --- */
99 static scansrc_ops fscan_ops = { fscan_scan, fscan_destroy };
101 /* --- @scan_file@ --- *
103 * Arguments: @FILE *fp@ = pointer to file descriptor
104 * @const char *name@ = pointer to source file name
105 * @unsigned f@ = flags
107 * Returns: A scanner source.
109 * Use: Creates a new scanner source for reading from a file.
112 scansrc *scan_file(FILE *fp, const char *name, unsigned f)
114 fscan *fs = CREATE(fscan);
115 fs->ss.ops = &fscan_ops;
116 fs->ss.src = xstrdup(name);
123 /*---- Argv scanner source ------------------------------------------------*/
125 /* --- Argv scanner block --- */
127 typedef struct avscan {
135 static int avscan_scan(scansrc *ss)
137 avscan *as = (avscan *)ss;
141 else if ((ch = (unsigned char)*as->p++) == 0) {
149 /* --- @destroy@ --- */
151 static void avscan_destroy(scansrc *ss)
153 avscan *as = (avscan *)ss;
157 /* --- Argv scanner operations --- */
159 static scansrc_ops avscan_ops = { avscan_scan, avscan_destroy };
161 /* --- @scan_argv@ --- *
163 * Arguments: @char **av@ = pointer to argument array (null terminated)
165 * Returns: A scanner source.
167 * Use: Creates a new scanner source for reading from an @argv@
171 scansrc *scan_argv(char **av)
173 avscan *as = CREATE(avscan);
174 as->ss.ops = &avscan_ops;
175 as->ss.src = "<argv>";
182 /*----- End-of-file sentinel block ----------------------------------------*/
186 static int eof_scan(scansrc *ss)
191 /* --- @destroy@ --- */
193 static void eof_destroy(scansrc *ss)
198 /* --- Eof scanner operations --- */
200 static scansrc_ops eof_ops = { eof_scan, eof_destroy };
202 /* --- The end of file marker --- */
204 static scansrc scan_eof = { &scan_eof, &eof_ops, "<eof>", 0, DSTR_INIT };
206 /*----- General scanner handling ------------------------------------------*/
210 * Arguments: @scanner *sc@ = pointer to main scanner context
212 * Returns: Character read, or end-of-file.
214 * Use: Scans a character from a source of characters.
217 int scan(scanner *sc)
220 if (sc->head->pushback.len)
221 ch = sc->head->pushback.buf[--sc->head->pushback.len];
223 scansrc *ss = sc->head;
226 else if ((ch = ss->ops->scan(ss)) == EOF) {
228 if (sc->head == &scan_eof)
229 sc->tail = &sc->head;
230 ss->ops->destroy(ss);
237 /* --- @unscan@ --- *
239 * Arguments: @scanner *sc@ = pointer to main scanner context
240 * @int ch@ = character to unscan
244 * Use: Scans a character from a source of characters.
247 void unscan(scanner *sc, int ch)
249 DPUTC(&sc->head->pushback, ch);
252 /* --- @scan_push@ --- *
254 * Arguments: @scanner *sc@ = pointer to main scanner context
255 * @scansrc *ss@ = souorce to push
259 * Use: Pushes a scanner source onto the front of the queue.
262 void scan_push(scanner *sc, scansrc *ss)
265 if (sc->head == &scan_eof)
266 sc->tail = &ss->next;
268 dstr_create(&ss->pushback);
273 /* --- @scan_add@ --- *
275 * Arguments: @scanner *sc@ = pointer to main scanner context
276 * @scansrc *ss@ = souorce to push
280 * Use: Adds a scanner source onto the end of the queue.
283 void scan_add(scanner *sc, scansrc *ss)
285 ss->next = &scan_eof;
287 sc->tail = &ss->next;
288 dstr_create(&ss->pushback);
293 /* --- @scan_create@ --- *
295 * Arguments: @scanner *sc@ = scanner context to initialize
299 * Use: Initializes a scanner block ready for use.
302 void scan_create(scanner *sc)
304 sc->head = &scan_eof;
305 sc->tail = &sc->head;
307 sc->wbegin = sc->wcont = 0;
310 /* --- @scan_destroy@ --- *
312 * Arguments: @scanner *sc@ = pointer to scanner context
316 * Use: Destroys a scanner and all the sources attached to it.
319 void scan_destroy(scanner *sc)
321 scansrc *ss = sc->head;
322 while (ss != &scan_eof) {
327 dstr_destroy(&sss->pushback);
328 sss->ops->destroy(sss);
330 dstr_destroy(&sc->d);
334 sc->head = &scan_eof;
335 sc->tail = &sc->head;
338 /*----- That's all, folks -------------------------------------------------*/