mdw@git.distorted.org.uk Git - fwd/blob - scan.c

   1 /* -*-c-*-
   2  *
   3  * $Id: scan.c,v 1.5 2002/01/30 09:29:34 mdw Exp $
   4  *
   5  * Character scanners
   6  *
   7  * (c) 1999 Straylight/Edgeware
   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 $
  32  * Revision 1.5  2002/01/30 09:29:34  mdw
  33  * Initialize scanner properly.
  34  *
  35  * Revision 1.4  2001/02/03 20:30:03  mdw
  36  * Support re-reading config files on SIGHUP.
  37  *
  38  * Revision 1.3  2000/08/01 17:58:10  mdw
  39  * Fix subtleties with <ctype.h> functions.
  40  *
  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.
  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>
  59 #include <mLib/sub.h>
  60
  61 #include "scan.h"
  62
  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;
  72
  73 /* --- @scan@ --- */
  74
  75 static int fscan_scan(scansrc *ss)
  76 {
  77   fscan *fs = (fscan *)ss;
  78   int ch = getc(fs->fp);
  79   if (ch == '\n')
  80     fs->ss.line++;
  81   return (ch);
  82 }
  83
  84 /* --- @destroy@ --- */
  85
  86 static void fscan_destroy(scansrc *ss)
  87 {
  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 }
  95
  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 {
 113   fscan *fs = CREATE(fscan);
 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@ --- */
 133
 134 static int avscan_scan(scansrc *ss)
 135 {
 136   avscan *as = (avscan *)ss;
 137   int ch;
 138   if (!as->p)
 139     ch = EOF;
 140   else if ((ch = (unsigned char)*as->p++) == 0) {
 141     as->ss.line++;
 142     as->p = *as->av++;
 143     ch = '\n';
 144   }
 145   return (ch);
 146 }
 147
 148 /* --- @destroy@ --- */
 149
 150 static void avscan_destroy(scansrc *ss)
 151 {
 152   avscan *as = (avscan *)ss;
 153   DESTROY(as);
 154 }
 155
 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)
 171 {
 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);
 179 }
 180
 181 /*----- End-of-file sentinel block ----------------------------------------*/
 182
 183 /* --- @scan@ --- */
 184
 185 static int eof_scan(scansrc *ss)
 186 {
 187   return (EOF);
 188 }
 189
 190 /* --- @destroy@ --- */
 191
 192 static void eof_destroy(scansrc *ss)
 193 {
 194   ;
 195 }
 196
 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)
 263 {
 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;
 271 }
 272
 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);
 307   sc->wbegin = sc->wcont = 0;
 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  */
 318
 319 void scan_destroy(scanner *sc)
 320 {
 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   }
 329   dstr_destroy(&sc->d);
 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;
 335 }
 336
 337 /*----- That's all, folks -------------------------------------------------*/