    // Copyright (C) 2006  Davis E. King (davis@dlib.net)
    // License: Boost Software License   See LICENSE.txt for the full license.
    #undef DLIB_BASE64_KERNEl_ABSTRACT_
    #ifdef DLIB_BASE64_KERNEl_ABSTRACT_

    #include "../algs.h"
    #include <iosfwd>

    namespace dlib
    {

        class base64
        {
            /*!
                INITIAL VALUE
                    - line_ending() == LF

                WHAT THIS OBJECT REPRESENTS
                    This object consists of the two functions encode and decode.
                    These functions allow you to encode and decode data to and from
                    the Base64 Content-Transfer-Encoding defined in section 6.8 of
                    rfc2045.
            !*/

        public:

            class decode_error : public dlib::error {};

            base64 (
            );
            /*!
                ensures
                    - #*this is properly initialized
                throws
                    - std::bad_alloc
            !*/

            virtual ~base64 (
            );
            /*!
                ensures
                    - all memory associated with *this has been released
            !*/

            enum line_ending_type
            {
                CR,  // i.e. "\r"
                LF,  // i.e. "\n"
                CRLF // i.e. "\r\n"
            };

            line_ending_type line_ending (
            ) const;
            /*!
                ensures
                    - returns the type of end of line bytes the encoder
                      will use when encoding data to base64 blocks.  Note that
                      the ostream object you use might apply some sort of transform
                      to line endings as well.  For example, C++ ofstream objects
                      usually convert '\n' into whatever a normal newline is for
                      your platform unless you open a file in binary mode.  But
                      aside from file streams the ostream objects usually don't
                      modify the data you pass to them.
            !*/

            void set_line_ending (
                line_ending_type eol_style
            );
            /*!
                ensures
                    - #line_ending() == eol_style
            !*/

            void encode (
                std::istream& in,
                std::ostream& out
            ) const;
            /*!
                ensures
                    - reads all data from in (until EOF is reached) and encodes it
                      and writes it to out
                throws
                    - std::ios_base::failure
                        if there was a problem writing to out then this exception will
                        be thrown.
                    - any other exception
                        this exception may be thrown if there is any other problem
            !*/

            void decode (
                std::istream& in,
                std::ostream& out
            ) const;
            /*!
                ensures
                    - reads data from in (until EOF is reached), decodes it,
                      and writes it to out.
                throws
                    - std::ios_base::failure
                        if there was a problem writing to out then this exception will
                        be thrown.
                    - decode_error
                        if an error was detected in the encoded data that prevented
                        it from being correctly decoded then this exception is
                        thrown.
                    - any other exception
                        this exception may be thrown if there is any other problem
            !*/

        private:

            // restricted functions
            base64(base64&);        // copy constructor
            base64& operator=(base64&);    // assignment operator

        };

    }

    #endif // DLIB_BASE64_KERNEl_ABSTRACT_