| 1 | /* -*-c-*- |
| 2 | * |
| 3 | * $Id: scan.c,v 1.2 1999/07/26 23:24:33 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 1.2 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. |
| 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> |
| 50 | #include <mLib/sub.h> |
| 51 | |
| 52 | #include "scan.h" |
| 53 | |
| 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; |
| 63 | |
| 64 | /* --- @scan@ --- */ |
| 65 | |
| 66 | static int fscan_scan(scansrc *ss) |
| 67 | { |
| 68 | fscan *fs = (fscan *)ss; |
| 69 | int ch = getc(fs->fp); |
| 70 | if (ch == '\n') |
| 71 | fs->ss.line++; |
| 72 | return (ch); |
| 73 | } |
| 74 | |
| 75 | /* --- @destroy@ --- */ |
| 76 | |
| 77 | static void fscan_destroy(scansrc *ss) |
| 78 | { |
| 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 | } |
| 86 | |
| 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@ --- */ |
| 124 | |
| 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 | } |
| 136 | return (ch); |
| 137 | } |
| 138 | |
| 139 | /* --- @destroy@ --- */ |
| 140 | |
| 141 | static void avscan_destroy(scansrc *ss) |
| 142 | { |
| 143 | avscan *as = (avscan *)ss; |
| 144 | DESTROY(as); |
| 145 | } |
| 146 | |
| 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) |
| 162 | { |
| 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); |
| 170 | } |
| 171 | |
| 172 | /*----- End-of-file sentinel block ----------------------------------------*/ |
| 173 | |
| 174 | /* --- @scan@ --- */ |
| 175 | |
| 176 | static int eof_scan(scansrc *ss) |
| 177 | { |
| 178 | return (EOF); |
| 179 | } |
| 180 | |
| 181 | /* --- @destroy@ --- */ |
| 182 | |
| 183 | static void eof_destroy(scansrc *ss) |
| 184 | { |
| 185 | ; |
| 186 | } |
| 187 | |
| 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) |
| 254 | { |
| 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; |
| 262 | } |
| 263 | |
| 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 | */ |
| 308 | |
| 309 | void scan_destroy(scanner *sc) |
| 310 | { |
| 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 | } |
| 319 | dstr_destroy(&sc->d); |
| 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; |
| 325 | } |
| 326 | |
| 327 | /*----- That's all, folks -------------------------------------------------*/ |