strings.c

編譯器的accent語法分析器

/*
 * ACCENT 
 * 
 * A Compiler Compiler for the Entire Class of Context-Free Languages
 * 
 * Copyright (C) 1999  Friedrich Wilhelm Schroeer
 * 
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */


#define PRIVATE static

/*--------------------------------------------------------------------*/

PRIVATE int initialized = 0;

PRIVATE char *p;     /* points to first free position of current buffer */
PRIVATE char *first; /* points to first char of current string */
PRIVATE char *start; /* points to first position of current buffer */
PRIVATE char *stop;  /* points to position after last char of current buffer */

PRIVATE long SIZE = 500;

#define INCR 500

/*--------------------------------------------------------------------*/

PRIVATE Allocate ()
{
   p = (char *) malloc (SIZE);
   if (p == 0) {
      printf("memory allocation failed\n");
      exit(1);
   }
   first = p;
   start = p;
   stop = p+SIZE;
}

/*--------------------------------------------------------------------*/

PRIVATE Initialize()
{
   Allocate();
   initialized = 1;
}

/*--------------------------------------------------------------------*/
AppendToString (ch)
   char ch;
{
   if ( ! initialized) Initialize();

   if (p == stop) { /* buffer full */
      char *q;
      char *qfirst = first;
      char *qstop = stop;

      if (first == start) SIZE += INCR;

      Allocate();
      for (q = qfirst; q != qstop; q++) {
	 *p++ = *q;
      }
   }
   *p++ = ch;
}

/*--------------------------------------------------------------------*/
GetStringRef(ref_string)
   char **ref_string;
{
   if ( ! initialized) Initialize();
   AppendToString(0);
   *ref_string = first;
   first = p;
}

/*--------------------------------------------------------------------*/