CString的MakeLower 特殊情况（乱码）下，转化会出错

测试代码如下：

	char szText[256] = {0xA6,0xA7,0xA8,0xA9};	/*	char szText[256] = {0};	for (int nIndex = 1; nIndex < 256; nIndex++)	{		szText[nIndex - 1] = (char)nIndex;	}	*/	CString strText = szText;	CString strLower = strText;	strLower.MakeLower();

WIN7 VC6，ANSI表情况

注意A8被转换了。

char szText[256] = {0xA6,0xA7,0xA8,0xA9};情况
VC6，VC2013，在WIN7系统的情况下

a6 a7 a8 a9 00

都会被转换为
a6 c7 a8 a9 00
结论：调用CString的MakeLower(),要确保CString没有乱码的情况。

建议使用STL的string,代码如下：

char szText[256] = {0xA6,0xA7,0xA8,0xA9};string strTest = szText;std::transform(strTest.begin(), strTest.end(), strTest.begin(), ::tolower);

经过IDA跟踪分析，CString最终调用MSVCRT(D).dll的_mbslwr(char* string)函数，

char *__cdecl _mbslwr(char *string){  unsigned __int8 v2; // [sp+0h] [bp-10h]@10  int retval; // [sp+4h] [bp-Ch]@4  char ret[4]; // [sp+8h] [bp-8h]@4  char *cp; // [sp+Ch] [bp-4h]@1  _lock(25);  for ( cp = string; *cp; ++cp )  {    if ( byte_10265061[(unsigned __int8)*cp] & 4 )    {      retval = __crtLCMapStringA(__mblcid, 0x100u, cp, 2, ret, 2, __mbcodepage, 1);      if ( !retval )      {        _unlock(25);        return 0;      }      *cp = ret[0];      if ( retval > 1 )        *++cp = ret[1];    }    else    {      if ( (byte_10265061[(unsigned __int8)*cp] & 0x10) == 0x10 )        v2 = _mbcasemap[(unsigned __int8)*cp];      else        v2 = *cp;      *cp = v2;    }  }  _unlock(25);  return string;}

而STL调用 MSVCRT(D).dll的int tolower( intc);

int __cdecl tolower(int c){  int result; // eax@5  int local_lock_flag; // [sp+0h] [bp-4h]@7  int ca; // [sp+Ch] [bp+8h]@9  if ( dword_10264B24 )  {    InterlockedIncrement(&__unguarded_readlc_active);    if ( __setlc_active )    {      InterlockedDecrement(&__unguarded_readlc_active);      _lock(19);      local_lock_flag = 1;    }    else    {      local_lock_flag = 0;    }    ca = _tolower_lk(c);    if ( local_lock_flag )      _unlock(19);    else      InterlockedDecrement(&__unguarded_readlc_active);    result = ca;  }  else  {    if ( c >= 65 && c <= 90 )      c += 32;    result = c;  }  return result;}