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/*
kmime_codec_base64.h
This file is part of KMime, the KDE internet mail/usenet news message library.
Copyright (c) 2001-2002 Marc Mutz <mutz@kde.org>
KMime is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License, version 2, as
published by the Free Software Foundation.
KMime is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received a copy of the GNU General Public License
along with this library; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
In addition, as a special exception, the copyright holders give
permission to link the code of this library with any edition of
the TQt library by Trolltech AS, Norway (or with modified versions
of TQt that use the same license as TQt), and distribute linked
combinations including the two. You must obey the GNU General
Public License in all respects for all of the code used other than
TQt. If you modify this file, you may extend this exception to
your version of the file, but you are not obligated to do so. If
you do not wish to do so, delete this exception statement from
your version.
*/
#ifndef __KMIME_CODEC_BASE64__
#define __KMIME_CODEC_BASE64__
#include "kmime_codecs.h"
namespace KMime {
class Base64Codec : public Codec {
protected:
friend class Codec;
Base64Codec() : Codec() {}
public:
virtual ~Base64Codec() {}
const char * name() const {
return "base64";
}
int maxEncodedSizeFor( int insize, bool withCRLF=false ) const {
// first, the total number of 4-char packets will be:
int totalNumPackets = ( insize + 2 ) / 3;
// now, after every 76/4'th packet there needs to be a linebreak:
int numLineBreaks = totalNumPackets / (76/4);
// and at the very end, too:
++numLineBreaks;
// putting it all together, we have:
return 4 * totalNumPackets + ( withCRLF ? 2 : 1 ) * numLineBreaks;
}
int maxDecodedSizeFor( int insize, bool withCRLF=false ) const {
// assuming all characters are part of the base64 stream (which
// does almost never hold due to required linebreaking; but
// additional non-base64 chars don't affect the output size), each
// 4-tupel of them becomes a 3-tupel in the decoded octet
// stream. So:
int result = ( ( insize + 3 ) / 4 ) * 3;
// but all of them may be \n, so
if ( withCRLF )
result *= 2; // :-o
return result;
}
Encoder * makeEncoder( bool withCRLF=false ) const;
Decoder * makeDecoder( bool withCRLF=false ) const;
};
class Rfc2047BEncodingCodec : public Base64Codec {
protected:
friend class Codec;
Rfc2047BEncodingCodec()
: Base64Codec() {}
public:
virtual ~Rfc2047BEncodingCodec() {}
const char * name() const { return "b"; }
int maxEncodedSizeFor( int insize, bool withCRLF=false ) const {
(void)withCRLF; // keep compiler happy
// Each (begun) 3-octet triple becomes a 4 char quartet, so:
return ( ( insize + 2 ) / 3 ) * 4;
}
int maxDecodedSizeFor( int insize, bool withCRLF=false ) const {
(void)withCRLF; // keep compiler happy
// Each 4-char quartet becomes a 3-octet triple, the last one
// possibly even less. So:
return ( ( insize + 3 ) / 4 ) * 3;
}
Encoder * makeEncoder( bool withCRLF=false ) const;
};
} // namespace KMime
#endif // __KMIME_CODEC_BASE64__
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