gcc/bi-lexer.c

   1 /* Lexer for scanner of bytecode definition file.
   2    Copyright (C) 1993, 1995 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, 59 Temple Place - Suite 330,
  19 Boston, MA 02111-1307, USA.  */
  20
  21 #include <stdio.h>
  22 #include "hconfig.h"
  23 #include "bi-parser.h"
  24
  25
  26 /* Safely allocate NBYTES bytes of memory.  Returns pointer to block of
  27    memory.  */
  28
  29 static char *
  30 xmalloc (nbytes)
  31      int nbytes;
  32 {
  33   char *tmp = (char *) malloc (nbytes);
  34
  35   if (!tmp)
  36     {
  37       fprintf (stderr, "can't allocate %d bytes (out of virtual memory)\n", nbytes);
  38       exit (FATAL_EXIT_CODE);
  39     }
  40
  41   return tmp;
  42 }
  43
  44
  45 /* Safely reallocate BLOCK so its size becomes NBYTES.
  46    The block returned may be different from the one supplied.  */
  47
  48 static char *
  49 xrealloc (block, nbytes)
  50      char *block;
  51      int nbytes;
  52 {
  53   char *tmp = (block
  54                ? (char *) realloc (block, nbytes)
  55                : (char *) malloc (nbytes));
  56
  57   if (!tmp)
  58     {
  59       fprintf (stderr, "can't reallocate %d bytes (out of virtual memory)\n", nbytes);
  60       exit (FATAL_EXIT_CODE);
  61     }
  62
  63   return tmp;
  64 }
  65
  66
  67 /* Scan for string token on standard input.  A string is, for our
  68    purposes here, a sequence of characters that starts with the regexp
  69    ``[^ #\t\n(),]'' and is then followed by the regexp ``[^#(),]*''. Any
  70    character is accepted if preceded by a backslash, "\\".  It is assumed
  71    that the first character has already been checked by the main loop.  */
  72
  73 static char *
  74 scan_string ()
  75 {
  76   char *buffer = NULL;
  77   char *point = NULL;
  78   int buffer_size = 0;
  79   int c;
  80
  81   while ((c = getc (stdin)) != EOF
  82          && c != '#' && c != '(' && c != ')' && c != ',')
  83     {
  84       /* Extend buffer, if necessary (minus two so there's room for the NUL
  85          trailer as well as another character if this one is a backslash).  */
  86       if (!buffer_size || (point - buffer >= buffer_size-2))
  87         {
  88           int previous_point_index = point - buffer;
  89
  90           buffer_size = (!buffer_size ? 32 : buffer_size * 2);
  91           if (!buffer)
  92             buffer = xmalloc (buffer_size);
  93           else
  94             buffer = xrealloc (buffer, buffer_size);
  95
  96           point = buffer + previous_point_index;
  97         }
  98       *point++ = c & 0xff;
  99
 100       if (c == '\\')
 101         {
 102           c = getc (stdin);
 103
 104           /* Catch special case: backslash at end of file */
 105           if (c == EOF)
 106             break;
 107
 108           *point++ = c;
 109         }
 110     }
 111   *point = 0;
 112
 113   if (c != EOF)
 114     ungetc (c, stdin);
 115
 116   return buffer;
 117 }
 118
 119
 120 int
 121 yylex ()
 122 {
 123   int c;
 124   char *token;
 125
 126
 127   /* First char determines what token we're looking at */
 128   for (;;)
 129     {
 130       c = getc (stdin);
 131
 132       switch (c)
 133         {
 134         case EOF:
 135           return 0;
 136
 137         case ' ':
 138         case '\t':
 139         case '\n':
 140           /* Ignore whitespace */
 141           continue;
 142
 143         case '#':
 144           /* Comments advance to next line */
 145           while ((c = getc (stdin)) != '\n' && c != EOF);
 146           continue;
 147
 148         default:
 149           if (c != '(' && c != ')' && c != '\\' && c != ',')
 150             {
 151               ungetc (c, stdin);
 152               yylval.string = scan_string ();
 153
 154               /* Check if string is "define_operator"; if so, return
 155                  a DEFOP token instead.  */
 156               if (!strcmp (yylval.string, "define_operator"))
 157                 {
 158                   free (yylval.string);
 159                   yylval.string = 0;
 160                   return DEFOP;
 161                 }
 162               return STRING;
 163             }
 164           return c & 0xff;
 165         }
 166     }
 167 }