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

   1 /* -*-c-*-
   2  *
   3  * $Id: scan.h,v 1.3 2002/01/13 14:50:07 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 1.3  2002/01/13 14:50:07  mdw
  33  * Make delimiters be a property of a scanner.
  34  *
  35  * Revision 1.2  1999/07/26 23:24:33  mdw
  36  * Complete rewrite.  Allow a list of character sources to enable changes
  37  * during parsing of syntactic constructs.
  38  *
  39  * Revision 1.1.1.1  1999/07/01 08:56:23  mdw
  40  * Initial revision.
  41  *
  42  */
  43
  44 #ifndef SCAN_H
  45 #define SCAN_H
  46
  47 #ifdef __cplusplus
  48   extern "C" {
  49 #endif
  50
  51 /*----- Header files ------------------------------------------------------*/
  52
  53 #include <stdio.h>
  54
  55 #include <mLib/dstr.h>
  56
  57 /*----- Data structures ---------------------------------------------------*/
  58
  59 /* --- A low-level scanner source --- */
  60
  61 typedef struct scansrc {
  62   struct scansrc *next;                 /* Next one in the list */
  63   struct scansrc_ops *ops;              /* Pointer to operations table */
  64   char *src;                            /* Name of this source */
  65   int line;                             /* Current line number */
  66   int pushback;                         /* Pushback character */
  67   char *tok;                            /* Token pushback */
  68   unsigned t;                           /* Token type pushback */
  69 } scansrc;
  70
  71 /* --- Scanner source operations --- */
  72
  73 typedef struct scansrc_ops {
  74   int (*scan)(scansrc */*ss*/);         /* Read another character */
  75   void (*destroy)(scansrc */*ss*/);     /* Destroy an unwanted source */
  76 } scansrc_ops;
  77
  78 /* --- A character scanner --- */
  79
  80 typedef struct scanner {
  81   scansrc *head, **tail;                /* Scanner list head and tail */
  82   int t;                                /* Token type */
  83   dstr d;                               /* Current token value */
  84   const char *wbegin, *wcont;           /* Parsing exception strings */
  85 } scanner;
  86
  87 /*----- Particular scanner types ------------------------------------------*/
  88
  89 /* --- @scan_file@ --- *
  90  *
  91  * Arguments:   @FILE *fp@ = pointer to file descriptor
  92  *              @char *name@ = pointer to source file name
  93  *              @unsigned f@ = flags
  94  *
  95  * Returns:     A scanner source.
  96  *
  97  * Use:         Creates a new scanner source for reading from a file.
  98  */
  99
 100 extern scansrc *scan_file(FILE */*fp*/, char */*name*/, unsigned /*f*/);
 101
 102 #define SCF_NOCLOSE 1u
 103 #define SCF_FREENAME 2u
 104
 105 /* --- @scan_argv@ --- *
 106  *
 107  * Arguments:   @char **av@ = pointer to argument array (null terminated)
 108  *
 109  * Returns:     A scanner source.
 110  *
 111  * Use:         Creates a new scanner source for reading from an @argv@
 112  *              array.
 113  */
 114
 115 extern scansrc *scan_argv(char **/*av*/);
 116
 117 /*----- General scanner handling ------------------------------------------*/
 118
 119 /* --- @scan@ --- *
 120  *
 121  * Arguments:   @scanner *sc@ = pointer to main scanner context
 122  *
 123  * Returns:     Character read, or end-of-file.
 124  *
 125  * Use:         Scans a character from a source of characters.
 126  */
 127
 128 extern int scan(scanner */*sc*/);
 129
 130 /* --- @unscan@ --- *
 131  *
 132  * Arguments:   @scanner *sc@ = pointer to main scanner context
 133  *              @int ch@ = character to unscan
 134  *
 135  * Returns:     ---
 136  *
 137  * Use:         Scans a character from a source of characters.
 138  */
 139
 140 extern void unscan(scanner */*sc*/, int /*ch*/);
 141
 142 /* --- @scan_push@ --- *
 143  *
 144  * Arguments:   @scanner *sc@ = pointer to main scanner context
 145  *              @scansrc *ss@ = souorce to push
 146  *
 147  * Returns:     ---
 148  *
 149  * Use:         Pushes a scanner source onto the front of the queue.
 150  */
 151
 152 extern void scan_push(scanner */*sc*/, scansrc */*ss*/);
 153
 154 /* --- @scan_add@ --- *
 155  *
 156  * Arguments:   @scanner *sc@ = pointer to main scanner context
 157  *              @scansrc *ss@ = souorce to push
 158  *
 159  * Returns:     ---
 160  *
 161  * Use:         Adds a scanner source onto the end of the queue.
 162  */
 163
 164 extern void scan_add(scanner */*sc*/, scansrc */*ss*/);
 165
 166 /* --- @scan_create@ --- *
 167  *
 168  * Arguments:   @scanner *sc@ = scanner context to initialize
 169  *
 170  * Returns:     ---
 171  *
 172  * Use:         Initializes a scanner block ready for use.
 173  */
 174
 175 extern void scan_create(scanner */*sc*/);
 176
 177 /* --- @scan_destroy@ --- *
 178  *
 179  * Arguments:   @scanner *sc@ = pointer to scanner context
 180  *
 181  * Returns:     ---
 182  *
 183  * Use:         Destroys a scanner and all the sources attached to it.
 184  */
 185
 186 extern void scan_destroy(scanner */*sc*/);
 187
 188 /*----- That's all, folks -------------------------------------------------*/
 189
 190 #ifdef __cplusplus
 191   }
 192 #endif
 193
 194 #endif