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

   1 /* -*-c-*-
   2  *
   3  * $Id: scan.h,v 1.4 2002/02/22 23:44:16 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.h,v $
  32  * Revision 1.4  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.
  35  *
  36  * Revision 1.3  2002/01/13 14:50:07  mdw
  37  * Make delimiters be a property of a scanner.
  38  *
  39  * Revision 1.2  1999/07/26 23:24:33  mdw
  40  * Complete rewrite.  Allow a list of character sources to enable changes
  41  * during parsing of syntactic constructs.
  42  *
  43  * Revision 1.1.1.1  1999/07/01 08:56:23  mdw
  44  * Initial revision.
  45  *
  46  */
  47
  48 #ifndef SCAN_H
  49 #define SCAN_H
  50
  51 #ifdef __cplusplus
  52   extern "C" {
  53 #endif
  54
  55 /*----- Header files ------------------------------------------------------*/
  56
  57 #include <stdio.h>
  58
  59 #include <mLib/dstr.h>
  60
  61 /*----- Data structures ---------------------------------------------------*/
  62
  63 /* --- A low-level scanner source --- */
  64
  65 typedef struct scansrc {
  66   struct scansrc *next;                 /* Next one in the list */
  67   struct scansrc_ops *ops;              /* Pointer to operations table */
  68   char *src;                            /* Name of this source */
  69   int line;                             /* Current line number */
  70   dstr pushback;                        /* Pushback characters */
  71   char *tok;                            /* Token pushback */
  72   unsigned t;                           /* Token type pushback */
  73 } scansrc;
  74
  75 /* --- Scanner source operations --- */
  76
  77 typedef struct scansrc_ops {
  78   int (*scan)(scansrc */*ss*/);         /* Read another character */
  79   void (*destroy)(scansrc */*ss*/);     /* Destroy an unwanted source */
  80 } scansrc_ops;
  81
  82 /* --- A character scanner --- */
  83
  84 typedef struct scanner {
  85   scansrc *head, **tail;                /* Scanner list head and tail */
  86   int t;                                /* Token type */
  87   dstr d;                               /* Current token value */
  88   const char *wbegin, *wcont;           /* Parsing exception strings */
  89 } scanner;
  90
  91 /*----- Particular scanner types ------------------------------------------*/
  92
  93 /* --- @scan_file@ --- *
  94  *
  95  * Arguments:   @FILE *fp@ = pointer to file descriptor
  96  *              @const char *name@ = pointer to source file name
  97  *              @unsigned f@ = flags
  98  *
  99  * Returns:     A scanner source.
 100  *
 101  * Use:         Creates a new scanner source for reading from a file.
 102  */
 103
 104 #define SCF_NOCLOSE 1u                  /* Don't close @fp@ when finished */
 105
 106 extern scansrc *scan_file(FILE */*fp*/, const char */*name*/,
 107                           unsigned /*f*/);
 108
 109 /* --- @scan_argv@ --- *
 110  *
 111  * Arguments:   @char **av@ = pointer to argument array (null terminated)
 112  *
 113  * Returns:     A scanner source.
 114  *
 115  * Use:         Creates a new scanner source for reading from an @argv@
 116  *              array.
 117  */
 118
 119 extern scansrc *scan_argv(char **/*av*/);
 120
 121 /*----- General scanner handling ------------------------------------------*/
 122
 123 /* --- @scan@ --- *
 124  *
 125  * Arguments:   @scanner *sc@ = pointer to main scanner context
 126  *
 127  * Returns:     Character read, or end-of-file.
 128  *
 129  * Use:         Scans a character from a source of characters.
 130  */
 131
 132 extern int scan(scanner */*sc*/);
 133
 134 /* --- @unscan@ --- *
 135  *
 136  * Arguments:   @scanner *sc@ = pointer to main scanner context
 137  *              @int ch@ = character to unscan
 138  *
 139  * Returns:     ---
 140  *
 141  * Use:         Scans a character from a source of characters.
 142  */
 143
 144 extern void unscan(scanner */*sc*/, int /*ch*/);
 145
 146 /* --- @scan_push@ --- *
 147  *
 148  * Arguments:   @scanner *sc@ = pointer to main scanner context
 149  *              @scansrc *ss@ = souorce to push
 150  *
 151  * Returns:     ---
 152  *
 153  * Use:         Pushes a scanner source onto the front of the queue.
 154  */
 155
 156 extern void scan_push(scanner */*sc*/, scansrc */*ss*/);
 157
 158 /* --- @scan_add@ --- *
 159  *
 160  * Arguments:   @scanner *sc@ = pointer to main scanner context
 161  *              @scansrc *ss@ = souorce to push
 162  *
 163  * Returns:     ---
 164  *
 165  * Use:         Adds a scanner source onto the end of the queue.
 166  */
 167
 168 extern void scan_add(scanner */*sc*/, scansrc */*ss*/);
 169
 170 /* --- @scan_create@ --- *
 171  *
 172  * Arguments:   @scanner *sc@ = scanner context to initialize
 173  *
 174  * Returns:     ---
 175  *
 176  * Use:         Initializes a scanner block ready for use.
 177  */
 178
 179 extern void scan_create(scanner */*sc*/);
 180
 181 /* --- @scan_destroy@ --- *
 182  *
 183  * Arguments:   @scanner *sc@ = pointer to scanner context
 184  *
 185  * Returns:     ---
 186  *
 187  * Use:         Destroys a scanner and all the sources attached to it.
 188  */
 189
 190 extern void scan_destroy(scanner */*sc*/);
 191
 192 /*----- That's all, folks -------------------------------------------------*/
 193
 194 #ifdef __cplusplus
 195   }
 196 #endif
 197
 198 #endif