chiark - git - mdw - fwd/blob - conf.h

   1 /* -*-c-*-
   2  *
   3  * $Id: conf.h,v 1.2 1999/07/26 23:28:39 mdw Exp $
   4  *
   5  * Configuration parsing
   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: conf.h,v $
  32  * Revision 1.2  1999/07/26 23:28:39  mdw
  33  * Major reconstruction work for new design.
  34  *
  35  * Revision 1.1.1.1  1999/07/01 08:56:23  mdw
  36  * Initial revision.
  37  *
  38  */
  39
  40 #ifndef CONF_H
  41 #define CONF_H
  42
  43 #ifdef __cplusplus
  44   extern "C" {
  45 #endif
  46
  47 /*----- Header files ------------------------------------------------------*/
  48
  49 #include <mLib/dstr.h>
  50
  51 #ifndef SCAN_H
  52 #  include "scan.h"
  53 #endif
  54
  55 /*----- Magic numbers -----------------------------------------------------*/
  56
  57 #define CTOK_EOF (-1)
  58 #define CTOK_WORD 256
  59
  60 /*----- Functions provided ------------------------------------------------*/
  61
  62 /* --- @token@ --- *
  63  *
  64  * Arguments:   @scanner *sc@ = pointer to scanner definition
  65  *
  66  * Returns:     Type of token scanned.
  67  *
  68  * Use:         Reads the next token from the character scanner.
  69  */
  70
  71 extern int token(scanner */*sc*/);
  72
  73 /* --- @error@ --- *
  74  *
  75  * Arguments:   @scanner *sc@ = pointer to scanner definition
  76  *              @const char *msg@ = message skeleton string
  77  *              @...@ = extra arguments for the skeleton
  78  *
  79  * Returns:     Doesn't
  80  *
  81  * Use:         Reports an error at the current scanner location.
  82  */
  83
  84 extern void error(scanner */*sc*/, const char */*msg*/, ...);
  85
  86 /* --- @conf_enum@ --- *
  87  *
  88  * Arguments:   @scanner *sc@ = pointer to a scanner object
  89  *              @const char *list@ = comma-separated things to allow
  90  *              @unsigned @f = flags for the search
  91  *              @const char *err@ = error message if not found
  92  *
  93  * Returns:     Index into list, zero-based, or @-1@.
  94  *
  95  * Use:         Checks whether the current token is a string which matches
  96  *              one of the comma-separated items given.  If not, an error is
  97  *              reported; otherwise the index of the matched item is
  98  *              returned.
  99  */
 100
 101 #define ENUM_ABBREV 1u
 102 #define ENUM_NONE 2u
 103
 104 extern int conf_enum(scanner */*sc*/, const char */*list*/,
 105                      unsigned /*flags*/, const char */*err*/);
 106
 107 /* --- @conf_prefix@ --- *
 108  *
 109  * Arguments:   @scanner *sc@ = pointer to a scanner object
 110  *              @const char *p@ = pointer to prefix string to check
 111  *
 112  * Returns:     Nonzero if the prefix matches.
 113  *
 114  * Use:         If the current token is a word matching the given prefix
 115  *              string, then it and an optional `.' character are removed and
 116  *              a nonzero result is returned.  Otherwise the current token is
 117  *              left as it is, and zero is returned.
 118  *
 119  *              Typical options parsing code would remove an expected prefix,
 120  *              scan an option anyway (since qualifying prefixes are
 121  *              optional) and if a match is found, claim the option.  If no
 122  *              match is found, and a prefix was stripped, then an error
 123  *              should be reported.
 124  */
 125
 126 extern int conf_prefix(scanner */*sc*/, const char */*p*/);
 127
 128 /* --- @CONF_BEGIN@, @CONF_ACCEPT@, @CONF_END@ --- *
 129  *
 130  * Arguments:   @sc@ = scanner to read from
 131  *              @prefix@ = prefix to scan for
 132  *              @desc@ = description of what we're parsing
 133  *
 134  * Use:         Bracket an options parsing routine.
 135  */
 136
 137 #define CS_PLAIN 0
 138 #define CS_PREFIX 1
 139 #define CS_BRACE 2
 140 #define CS_UNKNOWN 3
 141
 142 #define CONF_BEGIN(sc, prefix, desc) do {                               \
 143   scanner *_conf_sc = (sc);                                             \
 144   const char *_conf_desc = (desc);                                      \
 145   int _conf_state = CS_PLAIN;                                           \
 146   if (_conf_sc->t == CTOK_WORD &&                                       \
 147       strcmp(_conf_sc->d.buf, (prefix)) == 0) {                         \
 148     token(_conf_sc);                                                    \
 149     _conf_state = CS_PREFIX;                                            \
 150     if (_conf_sc->t == '.')                                             \
 151       token(_conf_sc);                                                  \
 152     else if (_conf_sc->t == '{') {                                      \
 153       token(_conf_sc);                                                  \
 154       _conf_state = CS_BRACE;                                           \
 155     }                                                                   \
 156   }                                                                     \
 157   if (_conf_sc->t != CTOK_WORD)                                         \
 158     error(_conf_sc, "parse error, expected option keyword");            \
 159   do {
 160
 161 #define CONF_ACCEPT goto _conf_accept
 162 #define CONF_REJECT goto _conf_reject
 163 #define CONF_QUAL (_conf_state != CS_PLAIN)
 164
 165 #define CONF_END                                                        \
 166   _conf_reject:                                                         \
 167     if (_conf_state == CS_PLAIN)                                        \
 168       _conf_state = CS_UNKNOWN;                                         \
 169     else {                                                              \
 170       error(_conf_sc, "unknown %s option `%s'",                         \
 171             _conf_desc, _conf_sc->d.buf);                               \
 172     }                                                                   \
 173   _conf_accept:                                                         \
 174     if (_conf_state == CS_BRACE && _conf_sc->t == ';')                  \
 175       token(_conf_sc);                                                  \
 176   } while (_conf_state == CS_BRACE && _conf_sc->t == CTOK_WORD);        \
 177   if (_conf_state == CS_BRACE) {                                        \
 178     if (_conf_sc->t == '}')                                             \
 179       token(_conf_sc);                                                  \
 180     else                                                                \
 181       error(_conf_sc, "parse error, expected `}'");                     \
 182   }                                                                     \
 183   return (_conf_state != CS_UNKNOWN);                                   \
 184 } while (0)
 185
 186 /* --- @conf_name@ --- *
 187  *
 188  * Arguments:   @scanner *sc@ = pointer to scanner
 189  *              @char delim@ = delimiter character to look for
 190  *              @dstr *d@ = pointer to dynamic string for output
 191  *
 192  * Returns:     ---
 193  *
 194  * Use:         Reads in a compound name consisting of words separated by
 195  *              delimiters.  Leading and trailing delimiters are permitted,
 196  *              although they'll probably cause confusion if used.  The name
 197  *              may be enclosed in square brackets if that helps at all.
 198  *
 199  *              Examples of compound names are filenames (delimited by `/')
 200  *              and IP addresses (delimited by `.').
 201  */
 202
 203 extern void conf_name(scanner */*sc*/, char /*delim*/, dstr */*d*/);
 204
 205 /* --- @conf_parse@ --- *
 206  *
 207  * Arguments:   @scanner *sc@ = pointer to a scanner structure
 208  *
 209  * Returns:     ---
 210  *
 211  * Use:         Parses a configuration file fragment from the scanner
 212  */
 213
 214 extern void conf_parse(scanner *sc);
 215
 216 /*----- That's all, folks -------------------------------------------------*/
 217
 218 #ifdef __cplusplus
 219   }
 220 #endif
 221
 222 #endif