uint.gsp

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

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

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

    register unsigned long uVal = 0;
    register unsigned long uCount = 0;
    char c = 0;        		
    register const unsigned long CHECK_MAX = ULONG_MAX/10; 

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

	uVal = uVal*10;
	if ( (uVal + (c - '0')) < uVal)
	  {
	    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 
	UnsignedInteger::operator=(uVal);
      }
  }}
  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.