int ciCharCompare(char c1,char c2)
{
	int lc1 = tolower(static_cast<unsigned char>c1);
	int lc2 = tolower(static_cast<unsigned char>c2);
	
	if(lc1 < lc2)
		return -1;
	if(lc1 > lc2)
		return 1;
	return 0;
}

int ciStringCompare(const string& s1,const string& s2)
{
	if(s1.size() < s2.size())
		return ciCharCompareImp(s1,s2);
	else
		return -ciCharCompareImp(s2,s1);
}

int ciCharCompareImp(const string& s1,const string& s2)
{
	typedef pair<string::const_iterator,string::const_iterator> PSCI;
	
	PSCI p = mismatch(
				s1.begin(),s1.end(),
				s2.begin(),
				not2(ptr_fun(ciCharCompare))
			);
			
	if(p.first == s1.end())
	{
		if(p.second == s2.end())
			return 0;
		else
			return -1;
	}
	
	return ciCharCompare(*p.first,*p.second);
}

bool ciCharLess(char c1,char c2)
{
	return tolower(static_cast<unsigned char>c1) < tolower(static_cast<unsigned char>c2);
}

bool ciStringCompare(const string& s1,const string& s2)
{
	return lexicographical_compare(s1.begin(),s1.end(),
					s2.begin(),s2.end(),
						ciCharLess);
}

int ciStringCompare(const string& s1,const string& s2)
{
	return strcasecmp(s1.c_str(),s2.c_str()); //stricmp是windows下的，strcasecmp是linux下的
}