base64.h

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//  base64.hpp 
//  Autor Konstantin Pilipchuk
//  mailto:lostd@ukr.net
//
//

#if !defined(__BASE64_H_INCLUDED__)
#define __BASE64_H_INCLUDED__ 1

#ifndef MAKEDEPEND
# include <iterator>
#endif

#include <ios>

static
int _base64Chars[]= {'A','B','C','D','E','F','G','H','I','J','K','L','M','N','O','P','Q','R','S','T','U','V','W','X','Y','Z',
                                     'a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z',
                                 '0','1','2','3','4','5','6','7','8','9',
                                 '+','/' };


#define _0000_0011 0x03
#define _1111_1100 0xFC
#define _1111_0000 0xF0
#define _0011_0000 0x30
#define _0011_1100 0x3C
#define _0000_1111 0x0F
#define _1100_0000 0xC0
#define _0011_1111 0x3F

#define _EQUAL_CHAR   (-1)
#define _UNKNOWN_CHAR (-2)

#define _IOS_FAILBIT   std::ios_base::failbit
#define _IOS_EOFBIT    std::ios_base::eofbit
#define _IOS_BADBIT    std::ios_base::badbit
#define _IOS_GOODBIT   std::ios_base::goodbit

// TEMPLATE CLASS base64_put
template<class _E = char, class _Tr = std::char_traits<_E> >
class base64
{
public:

        typedef unsigned char byte_t;
        typedef _E            char_type;
        typedef _Tr           traits_type; 

        // base64 requires max line length <= 72 characters
        // you can fill end of line
        // it may be crlf, crlfsp, noline or other class like it


        struct crlf
        {
                template<class _OI>
                        _OI operator()(_OI _To) const{
                        *_To = _Tr::to_char_type('\r'); ++_To;
                        *_To = _Tr::to_char_type('\n'); ++_To;

                        return (_To);
                }
        };


        struct crlfsp
        {
                template<class _OI>
                        _OI operator()(_OI _To) const{
                        *_To = _Tr::to_char_type('\r'); ++_To;
                        *_To = _Tr::to_char_type('\n'); ++_To;
                        *_To = _Tr::to_char_type(' '); ++_To;

                        return (_To);
                }
        };

        struct noline
        {
                template<class _OI>
                        _OI operator()(_OI _To) const{
                        return (_To);
                }
        };

        struct three2four
        {
                void zero()
                {
                        _data[0] = 0;
                        _data[1] = 0;
                        _data[2] = 0;
                }

                byte_t get_0()  const
                {
                        return _data[0];
                }
                byte_t get_1()  const
                {
                        return _data[1];
                }
                byte_t get_2()  const
                {
                        return _data[2];
                }

                void set_0(byte_t _ch)
                {
                        _data[0] = _ch;
                }

                void set_1(byte_t _ch)
                {
                        _data[1] = _ch;
                }

                void set_2(byte_t _ch)
                {
                        _data[2] = _ch;
                }

                // 0000 0000  1111 1111  2222 2222
                // xxxx xxxx  xxxx xxxx  xxxx xxxx
                // 0000 0011  1111 2222  2233 3333

                int b64_0()     const   {return (_data[0] & _1111_1100) >> 2;}
                int b64_1()     const   {return ((_data[0] & _0000_0011) << 4) + ((_data[1] & _1111_0000)>>4);}
                int b64_2()     const   {return ((_data[1] & _0000_1111) << 2) + ((_data[2] & _1100_0000)>>6);}
                int b64_3()     const   {return (_data[2] & _0011_1111);}

                void b64_0(int _ch)     {_data[0] = ((_ch & _0011_1111) << 2) | (_0000_0011 & _data[0]);}

                void b64_1(int _ch)     {
                        _data[0] = ((_ch & _0011_0000) >> 4) | (_1111_1100 & _data[0]);
                        _data[1] = ((_ch & _0000_1111) << 4) | (_0000_1111 & _data[1]); }

                void b64_2(int _ch)     {
                        _data[1] = ((_ch & _0011_1100) >> 2) | (_1111_0000 & _data[1]);
                        _data[2] = ((_ch & _0000_0011) << 6) | (_0011_1111 & _data[2]); }

                void b64_3(int _ch){
                        _data[2] = (_ch & _0011_1111) | (_1100_0000 & _data[2]);}

        private:
                byte_t _data[3];

        };




        template<class _II, class _OI, class _State, class _Endline>
        _II put(_II _First, _II _Last, _OI _To, _State&, _Endline)  const
        {
                three2four _3to4;
                int line_octets = 0;

                while(_First != _Last)
                {
                        _3to4.zero();

                        _3to4.set_0(*_First);
                        _First++;

                        if(_First == _Last)
                        {
                                *_To = _Tr::to_char_type(_base64Chars[_3to4.b64_0()]); ++_To;
                                *_To = _Tr::to_char_type(_base64Chars[_3to4.b64_1()]); ++_To;
                                *_To = _Tr::to_char_type('='); ++_To;
                                *_To = _Tr::to_char_type('='); ++_To;
                                goto __end;
                        }

                        _3to4.set_1(*_First);
                        _First++;

                        if(_First == _Last)
                        {
                                *_To = _Tr::to_char_type(_base64Chars[_3to4.b64_0()]); ++_To;
                                *_To = _Tr::to_char_type(_base64Chars[_3to4.b64_1()]); ++_To;
                                *_To = _Tr::to_char_type(_base64Chars[_3to4.b64_2()]); ++_To;
                                *_To = _Tr::to_char_type('='); ++_To;
                                goto __end;
                        }

                        _3to4.set_2(*_First);
                        _First++;

                        *_To = _Tr::to_char_type(_base64Chars[_3to4.b64_0()]); ++_To;
                        *_To = _Tr::to_char_type(_base64Chars[_3to4.b64_1()]); ++_To;
                        *_To = _Tr::to_char_type(_base64Chars[_3to4.b64_2()]); ++_To;
                        *_To = _Tr::to_char_type(_base64Chars[_3to4.b64_3()]); ++_To;

                        if(line_octets == 17)
                        {
                                //_To = _Endl(_To);
                                *_To = '\n'; ++_To;
                                line_octets = 0;
                        }
                        else
                                ++line_octets;
                }

                __end: ;

                return (_First);

        }


        template<class _II, class _OI, class _State>
                _II get(_II _First, _II _Last, _OI _To, _State& _St) const
        {
                three2four _3to4;
                int _Char;

                while(_First != _Last)
                {

                        // Take octet
                        _3to4.zero();

                        // -- 0 --
                        // Search next valid char... 
                        while((_Char =  _getCharType(*_First)) < 0 && _Char == _UNKNOWN_CHAR)
                        {
                                if(++_First == _Last)
                                {
                                        _St |= _IOS_FAILBIT|_IOS_EOFBIT; return _First; // unexpected EOF
                                }
                        }

                        if(_Char == _EQUAL_CHAR){
                                // Error! First character in octet can't be '='
                                _St |= _IOS_FAILBIT; 
                                return _First; 
                        }
                        else
                                _3to4.b64_0(_Char);


                        // -- 1 --
                        // Search next valid char... 
                        while(++_First != _Last)
                                if((_Char = _getCharType(*_First)) != _UNKNOWN_CHAR)
                                        break;

                        if(_First == _Last)     {
                                _St |= _IOS_FAILBIT|_IOS_EOFBIT; // unexpected EOF 
                                return _First;
                        }

                        if(_Char == _EQUAL_CHAR){
                                // Error! Second character in octet can't be '='
                                _St |= _IOS_FAILBIT; 
                                return _First; 
                        }
                        else
                                _3to4.b64_1(_Char);


                        // -- 2 --
                        // Search next valid char... 
                        while(++_First != _Last)
                                if((_Char = _getCharType(*_First)) != _UNKNOWN_CHAR)
                                        break;

                        if(_First == _Last)     {
                                // Error! Unexpected EOF. Must be '=' or base64 character
                                _St |= _IOS_FAILBIT|_IOS_EOFBIT; 
                                return _First; 
                        }

                        if(_Char == _EQUAL_CHAR){
                                // OK!
                                _3to4.b64_2(0); 
                                _3to4.b64_3(0); 

                                // chek for EOF
                                if(++_First == _Last)
                                {
                                        // Error! Unexpected EOF. Must be '='. Ignore it.
                                        //_St |= _IOS_BADBIT|_IOS_EOFBIT;
                                        _St |= _IOS_EOFBIT;
                                }
                                else 
                                        if(_getCharType(*_First) != _EQUAL_CHAR)
                                        {
                                                // Error! Must be '='. Ignore it.
                                                //_St |= _IOS_BADBIT;
                                        }
                                else
                                        ++_First; // Skip '='

                                // write 1 byte to output
                                *_To = (byte_t) _3to4.get_0();
                                return _First;
                        }
                        else
                                _3to4.b64_2(_Char);


                        // -- 3 --
                        // Search next valid char... 
                        while(++_First != _Last)
                                if((_Char = _getCharType(*_First)) != _UNKNOWN_CHAR)
                                        break;

                        if(_First == _Last)     {
                                // Unexpected EOF. It's error. But ignore it.
                                //_St |= _IOS_FAILBIT|_IOS_EOFBIT; 
                                        _St |= _IOS_EOFBIT; 
                                
                                return _First; 
                        }

                        if(_Char == _EQUAL_CHAR)
                        {
                                // OK!
                                _3to4.b64_3(0); 

                                // write to output 2 bytes
                                *_To = (byte_t) _3to4.get_0();
                                *_To = (byte_t) _3to4.get_1();

                                ++_First; // set position to next character

                                return _First;
                        }
                        else
                                _3to4.b64_3(_Char);


                        // write to output 3 bytes
                        *_To = (byte_t) _3to4.get_0();
                        *_To = (byte_t) _3to4.get_1();
                        *_To = (byte_t) _3to4.get_2();

                        ++_First;
                        

                } // while(_First != _Last)

                return (_First);
        }

protected:
        
        int _getCharType(int _Ch) const
        {
                if(_base64Chars[62] == _Ch)
                        return 62;

                if(_base64Chars[63] == _Ch)
                        return 63;

                if((_base64Chars[0] <= _Ch) && (_base64Chars[25] >= _Ch))
                        return _Ch - _base64Chars[0];

                if((_base64Chars[26] <= _Ch) && (_base64Chars[51] >= _Ch))
                        return _Ch - _base64Chars[26] + 26;

                if((_base64Chars[52] <= _Ch) && (_base64Chars[61] >= _Ch))
                        return _Ch - _base64Chars[52] + 52;

                if(_Ch == _Tr::to_int_type('='))
                        return _EQUAL_CHAR;

                return _UNKNOWN_CHAR;
        }


};


#endif