168 lines
3.7 KiB
C
168 lines
3.7 KiB
C
/* Lexer for scanner of bytecode definition file.
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Copyright (C) 1993, 1995 Free Software Foundation, Inc.
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This file is part of GNU CC.
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GNU CC is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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GNU CC is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with GNU CC; see the file COPYING. If not, write to
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the Free Software Foundation, 59 Temple Place - Suite 330,
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Boston, MA 02111-1307, USA. */
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#include <stdio.h>
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#include "hconfig.h"
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#include "bi-parser.h"
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/* Safely allocate NBYTES bytes of memory. Returns pointer to block of
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memory. */
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static char *
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xmalloc (nbytes)
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int nbytes;
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{
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char *tmp = (char *) malloc (nbytes);
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if (!tmp)
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{
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fprintf (stderr, "can't allocate %d bytes (out of virtual memory)\n", nbytes);
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exit (FATAL_EXIT_CODE);
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}
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return tmp;
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}
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/* Safely reallocate BLOCK so its size becomes NBYTES.
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The block returned may be different from the one supplied. */
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static char *
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xrealloc (block, nbytes)
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char *block;
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int nbytes;
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{
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char *tmp = (block
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? (char *) realloc (block, nbytes)
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: (char *) malloc (nbytes));
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if (!tmp)
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{
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fprintf (stderr, "can't reallocate %d bytes (out of virtual memory)\n", nbytes);
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exit (FATAL_EXIT_CODE);
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}
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return tmp;
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}
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/* Scan for string token on standard input. A string is, for our
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purposes here, a sequence of characters that starts with the regexp
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``[^ #\t\n(),]'' and is then followed by the regexp ``[^#(),]*''. Any
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character is accepted if preceded by a backslash, "\\". It is assumed
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that the first character has already been checked by the main loop. */
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static char *
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scan_string ()
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{
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char *buffer = NULL;
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char *point = NULL;
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int buffer_size = 0;
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int c;
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while ((c = getc (stdin)) != EOF
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&& c != '#' && c != '(' && c != ')' && c != ',')
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{
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/* Extend buffer, if necessary (minus two so there's room for the NUL
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trailer as well as another character if this one is a backslash). */
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if (!buffer_size || (point - buffer >= buffer_size-2))
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{
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int previous_point_index = point - buffer;
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buffer_size = (!buffer_size ? 32 : buffer_size * 2);
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if (!buffer)
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buffer = xmalloc (buffer_size);
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else
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buffer = xrealloc (buffer, buffer_size);
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point = buffer + previous_point_index;
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}
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*point++ = c & 0xff;
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if (c == '\\')
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{
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c = getc (stdin);
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/* Catch special case: backslash at end of file */
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if (c == EOF)
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break;
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*point++ = c;
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}
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}
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*point = 0;
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if (c != EOF)
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ungetc (c, stdin);
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return buffer;
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}
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int
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yylex ()
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{
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int c;
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char *token;
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/* First char determines what token we're looking at */
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for (;;)
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{
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c = getc (stdin);
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switch (c)
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{
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case EOF:
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return 0;
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case ' ':
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case '\t':
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case '\n':
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/* Ignore whitespace */
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continue;
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case '#':
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/* Comments advance to next line */
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while ((c = getc (stdin)) != '\n' && c != EOF);
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continue;
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default:
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if (c != '(' && c != ')' && c != '\\' && c != ',')
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{
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ungetc (c, stdin);
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yylval.string = scan_string ();
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/* Check if string is "define_operator"; if so, return
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a DEFOP token instead. */
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if (!strcmp (yylval.string, "define_operator"))
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{
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free (yylval.string);
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yylval.string = 0;
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return DEFOP;
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}
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return STRING;
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}
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return c & 0xff;
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}
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}
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}
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