C++ how convert wide string to base64?

Question

What is the best way to convert wide string to base64?

Answer 1

Octet (8 bit symbols) -> Base64 (6 bit symbols) conversion works on bytes, not characters, so it works the same way independent of your string encoding.

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To be clear: Base64 is not a character encoding. Sender and receiver need to agree on the character encoding (ASCII, UTF-8, UTF-16, UCS-2, etc) as well as the transport method (Base64, gzip, etc).

Answer 2

To encode some data to base64 you can use Base64 class from the Xerces library. It could look like the following:

std::wstring input_string = SOME; // some wide string
// keep it in contiguous memory (the following string is not needed in C++0x)
std::vector<wchar_t> raw_str( input_string.begin(), input_string.end() );

XMLSize_t len;
XMLByte* data_encoded = xercesc::Base64::encode( reinterpret_cast<const XMLByte*>(&raw_str[0]), raw_str.size()*sizeof(wchar_t), &len );
XMLCh* text_encoded = xercesc::XMLString::transcode( reinterpret_cast<char*>(data_encoded) );

// here's text_encoded is encoded text
// do some with text_encoded

XMLString::release( &text_encoded );
XMLString::release( reinterpret_cast<char**>(&data_encoded) );

Answer 3

If you are using Visual C++ with MFC, there is already a library to do this. Check out Base64Encode and Base64Decode.