gcc/bi-lexer.c

   1 /* Lexer for scanner of bytecode definition file.
   2    Copyright (C) 1993 Free Software Foundation, Inc.
   3
   4 This file is part of GNU CC.
   5
   6 GNU CC is free software; you can redistribute it and/or modify
   7 it under the terms of the GNU General Public License as published by
   8 the Free Software Foundation; either version 2, or (at your option)
   9 any later version.
  10
  11 GNU CC is distributed in the hope that it will be useful,
  12 but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 GNU General Public License for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GNU CC; see the file COPYING.  If not, write to
  18 the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */
  19
  20 #include <stdio.h>
  21 #include "hconfig.h"
  22 #include "bi-parser.h"
  23
  24 /* Current read buffer and point */
  25 static char *buffer = NULL;
  26 static char *inpoint = NULL;
  27
  28
  29 /* Safely allocate NBYTES bytes of memory. Reuturns pointer to block of
  30    memory. */
  31
  32 static char *
  33 xmalloc (nbytes)
  34      int nbytes;
  35 {
  36   char *tmp = (char *) malloc (nbytes);
  37
  38   if (!tmp)
  39     {
  40       fprintf (stderr, "can't allocate %d bytes (out of virtual memory)\n", nbytes);
  41       exit (FATAL_EXIT_CODE);
  42     }
  43
  44   return tmp;
  45 }
  46
  47
  48 /* Safely reallocate BLOCK so its size becomes NBYTES.
  49    The block returned may be different from the one supplied. */
  50
  51 static char *
  52 xrealloc (block, nbytes)
  53      char *block;
  54      int nbytes;
  55 {
  56   char *tmp = (block
  57                ? (char *) realloc (block, nbytes)
  58                : (char *) malloc (nbytes));
  59
  60   if (!tmp)
  61     {
  62       fprintf (stderr, "can't reallocate %d bytes (out of virtual memory)\n", nbytes);
  63       exit (FATAL_EXIT_CODE);
  64     }
  65
  66   return tmp;
  67 }
  68
  69
  70 /* Scan for string token on standard input.  A string is, for our
  71    purposes here, a sequence of characters that starts with the regexp
  72    ``[^ #\t\n(),]'' and is then followed by the regexp ``[^#(),]*''. Any
  73    character is accepted if preceded by a backslash, "\\".  It is assumed
  74    that the first character has already been checked by the main loop. */
  75
  76 static char *
  77 scan_string ()
  78 {
  79   char *buffer = NULL;
  80   char *point = NULL;
  81   int buffer_size = 0;
  82   int c;
  83
  84   while ((c = getc (stdin)) != EOF
  85          && c != '#' && c != '(' && c != ')' && c != ',')
  86     {
  87       /* Extend buffer, if necessary (minus two so there's room for the NUL
  88          trailer as well as another character if this one is a backslash).  */
  89       if (!buffer_size || (point - buffer >= buffer_size-2))
  90         {
  91           int previous_point_index = point - buffer;
  92
  93           buffer_size = (!buffer_size ? 32 : buffer_size * 2);
  94           if (!buffer)
  95             buffer = xmalloc (buffer_size);
  96           else
  97             buffer = xrealloc (buffer, buffer_size);
  98
  99           point = buffer + previous_point_index;
 100         }
 101       *point++ = c & 0xff;
 102
 103       if (c == '\\')
 104         {
 105           c = getc (stdin);
 106
 107           /* Catch special case: backslash at end of file */
 108           if (c == EOF)
 109             break;
 110
 111           *point++ = c;
 112         }
 113     }
 114   *point = 0;
 115
 116   if (c != EOF)
 117     ungetc (c, stdin);
 118
 119   return buffer;
 120 }
 121
 122
 123 int
 124 yylex ()
 125 {
 126   int c;
 127   char *token;
 128
 129
 130   /* First char determines what token we're looking at */
 131   for (;;)
 132     {
 133       c = getc (stdin);
 134
 135       switch (c)
 136         {
 137         case EOF:
 138           return 0;
 139
 140         case ' ':
 141         case '\t':
 142         case '\n':
 143           /* Ignore whitespace */
 144           continue;
 145
 146         case '#':
 147           /* Comments advance to next line */
 148           while ((c = getc (stdin)) != '\n' && c != EOF);
 149           continue;
 150
 151         default:
 152           if (c != '(' && c != ')' && c != '\\' && c != ',')
 153             {
 154               ungetc (c, stdin);
 155               yylval.string = scan_string ();
 156
 157               /* Check if string is "define_operator"; if so, return
 158                  a DEFOP token instead.  */
 159               if (!strcmp (yylval.string, "define_operator"))
 160                 {
 161                   free (yylval.string);
 162                   yylval.string = 0;
 163                   return DEFOP;
 164                 }
 165               return STRING;
 166             }
 167           return c & 0xff;
 168         }
 169     }
 170 }