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

   1 /* -*-c-*-
   2  *
   3  * $Id: scan.h,v 1.5 2004/04/08 01:36:25 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 #ifndef SCAN_H
  30 #define SCAN_H
  31
  32 #ifdef __cplusplus
  33   extern "C" {
  34 #endif
  35
  36 /*----- Header files ------------------------------------------------------*/
  37
  38 #include <stdio.h>
  39
  40 #include <mLib/dstr.h>
  41
  42 /*----- Data structures ---------------------------------------------------*/
  43
  44 /* --- A low-level scanner source --- */
  45
  46 typedef struct scansrc {
  47   struct scansrc *next;                 /* Next one in the list */
  48   struct scansrc_ops *ops;              /* Pointer to operations table */
  49   char *src;                            /* Name of this source */
  50   int line;                             /* Current line number */
  51   dstr pushback;                        /* Pushback characters */
  52   char *tok;                            /* Token pushback */
  53   unsigned t;                           /* Token type pushback */
  54 } scansrc;
  55
  56 /* --- Scanner source operations --- */
  57
  58 typedef struct scansrc_ops {
  59   int (*scan)(scansrc */*ss*/);         /* Read another character */
  60   void (*destroy)(scansrc */*ss*/);     /* Destroy an unwanted source */
  61 } scansrc_ops;
  62
  63 /* --- A character scanner --- */
  64
  65 typedef struct scanner {
  66   scansrc *head, **tail;                /* Scanner list head and tail */
  67   int t;                                /* Token type */
  68   dstr d;                               /* Current token value */
  69   const char *wbegin, *wcont;           /* Parsing exception strings */
  70 } scanner;
  71
  72 /*----- Particular scanner types ------------------------------------------*/
  73
  74 /* --- @scan_file@ --- *
  75  *
  76  * Arguments:   @FILE *fp@ = pointer to file descriptor
  77  *              @const char *name@ = pointer to source file name
  78  *              @unsigned f@ = flags
  79  *
  80  * Returns:     A scanner source.
  81  *
  82  * Use:         Creates a new scanner source for reading from a file.
  83  */
  84
  85 #define SCF_NOCLOSE 1u                  /* Don't close @fp@ when finished */
  86
  87 extern scansrc *scan_file(FILE */*fp*/, const char */*name*/,
  88                           unsigned /*f*/);
  89
  90 /* --- @scan_argv@ --- *
  91  *
  92  * Arguments:   @char **av@ = pointer to argument array (null terminated)
  93  *
  94  * Returns:     A scanner source.
  95  *
  96  * Use:         Creates a new scanner source for reading from an @argv@
  97  *              array.
  98  */
  99
 100 extern scansrc *scan_argv(char **/*av*/);
 101
 102 /*----- General scanner handling ------------------------------------------*/
 103
 104 /* --- @scan@ --- *
 105  *
 106  * Arguments:   @scanner *sc@ = pointer to main scanner context
 107  *
 108  * Returns:     Character read, or end-of-file.
 109  *
 110  * Use:         Scans a character from a source of characters.
 111  */
 112
 113 extern int scan(scanner */*sc*/);
 114
 115 /* --- @unscan@ --- *
 116  *
 117  * Arguments:   @scanner *sc@ = pointer to main scanner context
 118  *              @int ch@ = character to unscan
 119  *
 120  * Returns:     ---
 121  *
 122  * Use:         Scans a character from a source of characters.
 123  */
 124
 125 extern void unscan(scanner */*sc*/, int /*ch*/);
 126
 127 /* --- @scan_push@ --- *
 128  *
 129  * Arguments:   @scanner *sc@ = pointer to main scanner context
 130  *              @scansrc *ss@ = souorce to push
 131  *
 132  * Returns:     ---
 133  *
 134  * Use:         Pushes a scanner source onto the front of the queue.
 135  */
 136
 137 extern void scan_push(scanner */*sc*/, scansrc */*ss*/);
 138
 139 /* --- @scan_add@ --- *
 140  *
 141  * Arguments:   @scanner *sc@ = pointer to main scanner context
 142  *              @scansrc *ss@ = souorce to push
 143  *
 144  * Returns:     ---
 145  *
 146  * Use:         Adds a scanner source onto the end of the queue.
 147  */
 148
 149 extern void scan_add(scanner */*sc*/, scansrc */*ss*/);
 150
 151 /* --- @scan_create@ --- *
 152  *
 153  * Arguments:   @scanner *sc@ = scanner context to initialize
 154  *
 155  * Returns:     ---
 156  *
 157  * Use:         Initializes a scanner block ready for use.
 158  */
 159
 160 extern void scan_create(scanner */*sc*/);
 161
 162 /* --- @scan_destroy@ --- *
 163  *
 164  * Arguments:   @scanner *sc@ = pointer to scanner context
 165  *
 166  * Returns:     ---
 167  *
 168  * Use:         Destroys a scanner and all the sources attached to it.
 169  */
 170
 171 extern void scan_destroy(scanner */*sc*/);
 172
 173 /*----- That's all, folks -------------------------------------------------*/
 174
 175 #ifdef __cplusplus
 176   }
 177 #endif
 178
 179 #endif