bug, infinity loop in string library stringex.h

[myfoundation]

stringex & wstringex both.

Sample:

std::stringex tmp = "a";
tmp.replace("a", "aa"); // INFINITY LOOP HERE

because

` stringex &replace(const string &needle, const string &s)
{
size_type
lastpos = 0,
thispos;

		while ((thispos = find(needle, lastpos)) != npos)
		{
			string::replace(thispos, needle.length(), s);
			lastpos = thispos + 1;
		}
		return *this;
	}

`
but need

` stringex &replace(const string &needle, const string &s)
{
size_type
lastpos = 0,
thispos;

		while ((thispos = find(needle, lastpos)) != npos)
		{
			string::replace(thispos, needle.length(), s);
			lastpos = thispos + s.length();
		}
		return *this;
	}

`