experiment:use rsize let std::wstring.compare is right

/// @file srcTestStringCompare.cpp
/// use rsize let std::wstring.compare is right
/// 今天遇到了std::wstring.compare两个相同的串, 却不相等的怪现象~

#include "stdafx.h"
#include <Windows.h>
#include <tchar.h>
#include <string>

#define G_STR_PATH_NAME	_T("c:\\test.txt")

BOOL	GetPathName(TCHAR * lpcPathName, size_t nLenPathName);
int _tmain(int argc, _TCHAR* argv[])
{
	INT				iRc		=	0;
	std::wstring	strObj;

	strObj.resize(_MAX_PATH);	///< 这么用, 是不想定义一个固定size的Buffer
	if(GetPathName((TCHAR *)strObj.c_str(), _MAX_PATH))
	{
		iRc = strObj.compare(G_STR_PATH_NAME);
		_tprintf(_T("%s and %s is %s\n"),
			strObj.c_str(),
			G_STR_PATH_NAME,
			(0 == iRc) ? _T("same") : _T("different"));
	}

	/// run results
	/**
	/// if we call std::wstring.rsize once, compare is wrong
	c:\test.txt and c:\test.txt is different
	*/

	strObj.resize(_MAX_PATH);
	if(GetPathName((TCHAR *)strObj.c_str(), _MAX_PATH))
	{
		strObj.resize(_tcslen(strObj.c_str()));	///< very important, because we call std::wstring.rsize once
		iRc = strObj.compare(G_STR_PATH_NAME);
		_tprintf(_T("%s and %s is %s\n"),
			strObj.c_str(),
			G_STR_PATH_NAME,
			(0 == iRc) ? _T("same") : _T("different"));
	}


	/// run results
	/**
	/// if we cal std::wstring.rsize once, need call rsize THE right string length
	c:\test.txt and c:\test.txt is same
	*/

	getchar();
	return 0;
}

BOOL	GetPathName(TCHAR * lpcPathName, size_t nLenPathName)
{
	if(		(NULL == lpcPathName)
		||	(nLenPathName < _tcslen(G_STR_PATH_NAME)))
	{
		return FALSE;
	}

	_tcscpy(lpcPathName, G_STR_PATH_NAME);

	return TRUE;
}