Add base64url_encode()

1 files changed, 19 insertions, 0 deletions

diff --git a/libbutl/base64.hxx b/libbutl/base64.hxx
index f38e62f..6f8ef02 100644
--- a/libbutl/base64.hxx
+++ b/libbutl/base64.hxx
@@ -27,6 +27,25 @@ namespace butl
   LIBBUTL_SYMEXPORT std::string
   base64_encode (const std::vector<char>&);
 
+  // Encode a stream or a buffer using base64url (RFC 4648), a base64 variant
+  // with different 62nd and 63rd alphabet characters (- and _ instead of ~
+  // and .) to make it filesystem safe, and optional padding because the
+  // padding character `=` would have to be percent-encoded to be safe in
+  // URLs.  This implementation does not output any padding, newlines or any
+  // other whitespace in order to conform to RFC7519: JSON Web Token (JWT) and
+  // RFC7515: JSON Web Signature (JWS).
+  //
+  // Note that base64url decoding has not yet been implemented.
+  //
+  LIBBUTL_SYMEXPORT void
+  base64url_encode (std::ostream&, std::istream&);
+
+  LIBBUTL_SYMEXPORT std::string
+  base64url_encode (std::istream&);
+
+  LIBBUTL_SYMEXPORT std::string
+  base64url_encode (const std::vector<char>&);
+
   // Base64-decode a stream or a string. Throw invalid_argument if the input
   // is not a valid base64 representation. If reading from a stream, check if
   // it has badbit, failbit, or eofbit set and throw invalid_argument if