UTF8 ANSI 相互转换的函数

#include <winnls.h>
#include <malloc.h>
LPCSTR AnsiToUtf8(LPCSTR Ansi)
{
int WLength = MultiByteToWideChar(CP_ACP, 0, Ansi, -1, NULL, 0);
LPWSTR pszW = (LPWSTR) _alloca((WLength+1) * sizeof(WCHAR));
MultiByteToWideChar(CP_ACP, 0, Ansi, -1, pszW, WLength);

int ALength = WideCharToMultiByte(CP_UTF8, 0, pszW, -1, NULL, 0, NULL, NULL);
LPSTR pszA = (LPSTR)_alloca( ALength + 1);
WideCharToMultiByte(CP_UTF8, 0, pszW, -1, pszA, ALength, NULL, NULL);
pszA[ALength] = 0;

return pszA;
}

LPCSTR WcharToUtf8(LPCWSTR szUnicode)
{
int ALength = WideCharToMultiByte(CP_UTF8, 0, szUnicode, -1, NULL, 0, NULL, NULL);
LPSTR pszA = (LPSTR)_alloca( ALength + 1);
WideCharToMultiByte(CP_UTF8, 0, szUnicode, -1, pszA, ALength, NULL, NULL);
pszA[ALength] = 0;

return pszA;
}

LPCSTR Utf8toAnsi( LPCSTR utf8 )
{
int WLength = MultiByteToWideChar(CP_UTF8, 0, utf8, -1, NULL, NULL );
LPWSTR pszW = (LPWSTR) _alloca( (WLength + 1) *sizeof(WCHAR) ) ;
MultiByteToWideChar(CP_UTF8, 0, utf8, -1, pszW, WLength );
pszW[WLength] = 0;

int ALength = WideCharToMultiByte(CP_ACP, 0, pszW, -1, NULL, 0, NULL, NULL);
LPSTR pszA = ( LPSTR ) _alloca ( ALength + 1 );
WideCharToMultiByte(CP_ACP, 0, pszW, -1, pszA, ALength, NULL, NULL);
pszA[ALength] = 0;

return pszA;
}

LPCWSTR Utf8toWchar( LPCSTR utf8 )
{
int WLength = MultiByteToWideChar(CP_UTF8, 0, utf8, -1, NULL, NULL );
LPWSTR pszW = (LPWSTR) _alloca( (WLength + 1) *sizeof(WCHAR) ) ;
MultiByteToWideChar(CP_UTF8, 0, utf8, -1, pszW, WLength );
pszW[WLength] = 0;
return pszW;
}