win api 实现 base64编码、解码

#pragma comment(lib,"crypt32.lib")

LPSTR Base64Encode(LPBYTE lpBuffer,DWORD dwLen)
{
	DWORD dwNeed;
	LPSTR lpBase64Str ;
	DWORD dwIndex ;
	DWORD dwIndexJ;
	dwNeed = 0;
	lpBase64Str = NULL ;
	
	CryptBinaryToStringA(lpBuffer,dwLen,CRYPT_STRING_BASE64,NULL,&dwNeed);

	if (dwNeed)
	{
		lpBase64Str = (LPSTR)malloc(dwNeed);
		ZeroMemory(lpBase64Str,dwNeed);
		CryptBinaryToStringA(lpBuffer,dwLen,CRYPT_STRING_BASE64,lpBase64Str,&dwNeed);
		dwIndex = 0;
		while(*(lpBase64Str+dwIndex)!=0)
		{
			if (*(lpBase64Str+dwIndex) == 0x0d || *(lpBase64Str+dwIndex)==0x0a)
			{
				dwIndexJ = dwIndex +1;
				
				while (*(lpBase64Str+dwIndexJ)!=0)
				{
					*(lpBase64Str+dwIndexJ-1)= *(lpBase64Str+dwIndexJ);
					dwIndexJ ++ ;
				}

				*(lpBase64Str+dwIndexJ-1) = 0 ;
				
			}else
			{
				dwIndex ++ ;
			}
			
		}
	}

	return lpBase64Str ;
}

LPBYTE Base64Decode(LPSTR lpBase64Str,LPDWORD lpdwLen)
{
	DWORD dwLen ;
	DWORD dwNeed ;
	LPBYTE lpBuffer ;

	dwLen = strlen(lpBase64Str);
	dwNeed = 0;
	CryptStringToBinaryA(lpBase64Str,0,CRYPT_STRING_BASE64,NULL,&dwNeed,NULL,NULL);
	if (dwNeed)
	{
		lpBuffer = (LPBYTE)malloc(dwNeed);
		CryptStringToBinaryA(lpBase64Str,0,CRYPT_STRING_BASE64,lpBuffer,&dwNeed,NULL,NULL);
		*lpdwLen = dwNeed ;
	}
	
	return lpBuffer ;
}