int.gsp

This is the verbatim text of the file "int.gsp" part of the LLOOP package. The copyright remains with Michel MEHL. All rights reserved.

/**
 * Reads a "long" C type (including overflow check). 
 */

token SignedIntegerToken extends class universal::SignedInteger()
  include <stdio.h>, <ctype.h>, <limits.h>, "universal__Numeric.h"
  alias "int"
  parse
  {{
    /* Seems to be less efficient than the code below
      unsigned long uVal = 0;
      if (is.scan("%ld", &iVal).fail())
      abort("");
      */

    register unsigned long uVal = 0;
    register unsigned long uCount = 0;
    char c = 0;        		
    register char minus = 1;
    register unsigned long MINUS_EXTRA = 0;
    register const unsigned long CHECK_MAX = (unsigned long) (LONG_MAX/10); 

    is.get(c);
    if (c == '-') 
      { 
	minus = -1;
	MINUS_EXTRA = 1;
	c = 0;
	is.get(c);
      }

    while ( isdigit(c) )
      {
	/* Overflow check */
	if (uVal > CHECK_MAX)
	  {
	    uCount = 0;
	    break;
	  }

	uVal = uVal*10;
	if ( (uVal + (c - '0')) > ((unsigned long)LONG_MAX + MINUS_EXTRA) )
	  {
	    uCount = 0;
	    break;
	  }
	uVal += (c - '0');
	uCount++;
	c = 0;
	is.get(c);
      } 

    if (uCount == 0)
      abort("");
    else 
      {      
	if (is.fail()) 
	  is.clear(); // In case of EOF
	else
	  is.seekg(-1, ios::cur); // Set position to the immediate following char 
	SignedInteger::operator=(uVal*minus);
      }
  }}
  expand
  {{
    os << toString();
  }}
  

This file is part of the LLOOP Reversible Object-Oriented Parser Generator. Copyright (c) 2005-2006 Michel MEHL, France. All rights reserved. LLOOP is distributed by the company ERSA SaRL.