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

   1 /* -*-c-*-
   2  *
   3  * Character scanners
   4  *
   5  * (c) 1999 Straylight/Edgeware
   6  */
   7
   8 /*----- Licensing notice --------------------------------------------------*
   9  *
  10  * This file is part of the `fwd' port forwarder.
  11  *
  12  * `fwd' is free software; you can redistribute it and/or modify
  13  * it under the terms of the GNU General Public License as published by
  14  * the Free Software Foundation; either version 2 of the License, or
  15  * (at your option) any later version.
  16  *
  17  * `fwd' is distributed in the hope that it will be useful,
  18  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20  * GNU General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU General Public License
  23  * along with `fwd'; if not, write to the Free Software Foundation,
  24  * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  25  */
  26
  27 #ifndef SCAN_H
  28 #define SCAN_H
  29
  30 #ifdef __cplusplus
  31   extern "C" {
  32 #endif
  33
  34 /*----- Header files ------------------------------------------------------*/
  35
  36 #include <stdio.h>
  37
  38 #include <mLib/dstr.h>
  39
  40 /*----- Data structures ---------------------------------------------------*/
  41
  42 /* --- A low-level scanner source --- */
  43
  44 typedef struct scansrc {
  45   struct scansrc *next;                 /* Next one in the list */
  46   struct scansrc_ops *ops;              /* Pointer to operations table */
  47   char *src;                            /* Name of this source */
  48   int line;                             /* Current line number */
  49   dstr pushback;                        /* Pushback characters */
  50   char *tok;                            /* Token pushback */
  51   unsigned t;                           /* Token type pushback */
  52 } scansrc;
  53
  54 /* --- Scanner source operations --- */
  55
  56 typedef struct scansrc_ops {
  57   int (*scan)(scansrc */*ss*/);         /* Read another character */
  58   void (*destroy)(scansrc */*ss*/);     /* Destroy an unwanted source */
  59 } scansrc_ops;
  60
  61 /* --- A character scanner --- */
  62
  63 typedef struct scanner {
  64   scansrc *head, **tail;                /* Scanner list head and tail */
  65   int t;                                /* Token type */
  66   dstr d;                               /* Current token value */
  67   const char *wbegin, *wcont;           /* Parsing exception strings */
  68 } scanner;
  69
  70 /*----- Particular scanner types ------------------------------------------*/
  71
  72 /* --- @scan_file@ --- *
  73  *
  74  * Arguments:   @FILE *fp@ = pointer to file descriptor
  75  *              @const char *name@ = pointer to source file name
  76  *              @unsigned f@ = flags
  77  *
  78  * Returns:     A scanner source.
  79  *
  80  * Use:         Creates a new scanner source for reading from a file.
  81  */
  82
  83 #define SCF_NOCLOSE 1u                  /* Don't close @fp@ when finished */
  84
  85 extern scansrc *scan_file(FILE */*fp*/, const char */*name*/,
  86                           unsigned /*f*/);
  87
  88 /* --- @scan_argv@ --- *
  89  *
  90  * Arguments:   @char **av@ = pointer to argument array (null terminated)
  91  *
  92  * Returns:     A scanner source.
  93  *
  94  * Use:         Creates a new scanner source for reading from an @argv@
  95  *              array.
  96  */
  97
  98 extern scansrc *scan_argv(char **/*av*/);
  99
 100 /*----- General scanner handling ------------------------------------------*/
 101
 102 /* --- @scan@ --- *
 103  *
 104  * Arguments:   @scanner *sc@ = pointer to main scanner context
 105  *
 106  * Returns:     Character read, or end-of-file.
 107  *
 108  * Use:         Scans a character from a source of characters.
 109  */
 110
 111 extern int scan(scanner */*sc*/);
 112
 113 /* --- @unscan@ --- *
 114  *
 115  * Arguments:   @scanner *sc@ = pointer to main scanner context
 116  *              @int ch@ = character to unscan
 117  *
 118  * Returns:     ---
 119  *
 120  * Use:         Scans a character from a source of characters.
 121  */
 122
 123 extern void unscan(scanner */*sc*/, int /*ch*/);
 124
 125 /* --- @scan_push@ --- *
 126  *
 127  * Arguments:   @scanner *sc@ = pointer to main scanner context
 128  *              @scansrc *ss@ = souorce to push
 129  *
 130  * Returns:     ---
 131  *
 132  * Use:         Pushes a scanner source onto the front of the queue.
 133  */
 134
 135 extern void scan_push(scanner */*sc*/, scansrc */*ss*/);
 136
 137 /* --- @scan_add@ --- *
 138  *
 139  * Arguments:   @scanner *sc@ = pointer to main scanner context
 140  *              @scansrc *ss@ = souorce to push
 141  *
 142  * Returns:     ---
 143  *
 144  * Use:         Adds a scanner source onto the end of the queue.
 145  */
 146
 147 extern void scan_add(scanner */*sc*/, scansrc */*ss*/);
 148
 149 /* --- @scan_create@ --- *
 150  *
 151  * Arguments:   @scanner *sc@ = scanner context to initialize
 152  *
 153  * Returns:     ---
 154  *
 155  * Use:         Initializes a scanner block ready for use.
 156  */
 157
 158 extern void scan_create(scanner */*sc*/);
 159
 160 /* --- @scan_destroy@ --- *
 161  *
 162  * Arguments:   @scanner *sc@ = pointer to scanner context
 163  *
 164  * Returns:     ---
 165  *
 166  * Use:         Destroys a scanner and all the sources attached to it.
 167  */
 168
 169 extern void scan_destroy(scanner */*sc*/);
 170
 171 /*----- That's all, folks -------------------------------------------------*/
 172
 173 #ifdef __cplusplus
 174   }
 175 #endif
 176
 177 #endif