sgpemv2/src/backend/string_utils.cc

// src/backend/string_utils.cc - Copyright 2005, 2006, University
//               of Padova, dept. of Pure and Applied
//               Mathematics
//
// This file is part of SGPEMv2.
//
// This 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.
//
// SGPEMv2 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 SGPEMv2; if not, write to the Free Software
// Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA

#include "string_utils.hh"

using Glib::ustring;

/**
	\brief A function that converts a Unicode string to an integer value
			   
	The string can contain ONLY digits and the "minus" character.

	\returns TRUE if the string is well formatted
	\returns FALSE otherwise	
*/
bool 
string_to_int(const ustring& str, int& num)
{
	static const ustring allvalid = "0123456789-";
	static const ustring digits = "0123456789";
	
	//	the string can't be empty
	if (str.length() == 0 || (str.length() == 1 && str[0] == '-'))
		return false;

	//checks if the string contains only digits
	if (str.find_first_not_of(allvalid) < str.length())
		return false;
	if (str.substr(1).find_first_not_of(digits) < str.length()-1)
		return false;
	
	num=0;
	int multiplier = 1, val;
	int start;	//the position of the biggest digit
	if (str[0] == '-')
		start = 1;
	else
		start = 0;
	for (int pos = str.length() - 1; pos >= start ; pos--)
	{
		val = str[pos] - 48;	//the INTEGER value of the digit
		num += val*multiplier;
		multiplier *= 10;		
	}
	//if there is the minus then multiply for -1
	if (start == 1)
		num *= -1;
	return true;	
}

/**
	\brief A function that converts an integer value to an Unicode string
 */
void
int_to_string(const int& num, ustring& str)
{
	if (num == 0)
	{
		str = '0';
		return;
	}
	
	str = "";
	int val = num;
	bool negative = (val < 0)? true : false;
	if (negative) val *= -1;
	
	while (true)
	{
		str = char(val % 10 + 48) + str;
		if (val > 1 && val / 10 != 0)
			val /= 10;
		else
			break;
	}
	if (negative)
		str = '-' + str;
}