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406 lines
12 KiB
406 lines
12 KiB
/* -*- c++ -*-
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kmime_codec_base64.cpp
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This file is part of KMime, the KDE internet mail/usenet news message library.
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Copyright (c) 2001 Marc Mutz <mutz@kde.org>
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KMime is free software; you can redistribute it and/or modify it
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under the terms of the GNU General Public License, version 2, as
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published by the Free Software Foundation.
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KMime is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this library; if not, write to the Free Software
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Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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In addition, as a special exception, the copyright holders give
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permission to link the code of this library with any edition of
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the TQt library by Trolltech AS, Norway (or with modified versions
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of TQt that use the same license as TQt), and distribute linked
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combinations including the two. You must obey the GNU General
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Public License in all respects for all of the code used other than
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TQt. If you modify this file, you may extend this exception to
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your version of the file, but you are not obligated to do so. If
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you do not wish to do so, delete this exception statement from
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your version.
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*/
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#include "kmime_codec_base64.h"
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#include <kdebug.h>
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#include <cassert>
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using namespace KMime;
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namespace KMime {
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// codec for base64 as specified in RFC 2045
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//class Base64Codec;
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//class Base64Decoder;
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//class Base64Encoder;
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// codec for the B encoding as specified in RFC 2047
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//class Rfc2047BEncodingCodec;
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//class Rfc2047BEncodingEncoder;
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//class Rfc2047BEncodingDecoder;
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static const uchar base64DecodeMap[128] = {
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64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
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64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
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64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 62, 64, 64, 64, 63,
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52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 64, 64, 64, 64, 64, 64,
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64, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14,
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15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 64, 64, 64, 64, 64,
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64, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
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41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 64, 64, 64, 64, 64
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};
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static const char base64EncodeMap[64] = {
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'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H',
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'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P',
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'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X',
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'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f',
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'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n',
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'o', 'p', 'q', 'r', 's', 't', 'u', 'v',
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'w', 'x', 'y', 'z', '0', '1', '2', '3',
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'4', '5', '6', '7', '8', '9', '+', '/'
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};
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class Base64Decoder : public Decoder {
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uint mStepNo;
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uchar mOutbits;
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bool mSawPadding : 1;
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protected:
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friend class Base64Codec;
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Base64Decoder( bool withCRLF=false )
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: Decoder( withCRLF ), mStepNo(0), mOutbits(0),
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mSawPadding(false) {}
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public:
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virtual ~Base64Decoder() {}
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bool decode( const char* & scursor, const char * const send,
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char* & dcursor, const char * const dend );
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// ### really needs no finishing???
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bool finish( char* & /*dcursor*/, const char * const /*dend*/ ) { return true; }
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};
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class Base64Encoder : public Encoder {
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uint mStepNo;
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/** number of already written base64-quartets on current line */
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uint mWrittenPacketsOnThisLine;
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uchar mNextbits;
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bool mInsideFinishing : 1;
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protected:
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friend class Rfc2047BEncodingCodec;
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friend class Rfc2047BEncodingEncoder;
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friend class Base64Codec;
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Base64Encoder( bool withCRLF=false )
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: Encoder( withCRLF ), mStepNo(0), mWrittenPacketsOnThisLine(0),
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mNextbits(0), mInsideFinishing(false) {}
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bool generic_finish( char* & dcursor, const char * const dend,
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bool withLFatEnd );
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public:
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virtual ~Base64Encoder() {}
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bool encode( const char* & scursor, const char * const send,
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char* & dcursor, const char * const dend );
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bool finish( char* & dcursor, const char * const dend );
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protected:
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bool writeBase64( uchar ch, char* & dcursor, const char * const dend ) {
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return write( base64EncodeMap[ ch ], dcursor, dend );
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}
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};
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class Rfc2047BEncodingEncoder : public Base64Encoder {
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protected:
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friend class Rfc2047BEncodingCodec;
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Rfc2047BEncodingEncoder( bool withCRLF=false )
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: Base64Encoder( withCRLF ) {};
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public:
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bool encode( const char* & scursor, const char * const send,
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char* & dcursor, const char * const dend );
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bool finish( char* & dcursor, const char * const dend );
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};
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Encoder * Base64Codec::makeEncoder( bool withCRLF ) const {
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return new Base64Encoder( withCRLF );
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}
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Decoder * Base64Codec::makeDecoder( bool withCRLF ) const {
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return new Base64Decoder( withCRLF );
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}
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Encoder * Rfc2047BEncodingCodec::makeEncoder( bool withCRLF ) const {
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return new Rfc2047BEncodingEncoder( withCRLF );
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}
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/********************************************************/
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/********************************************************/
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/********************************************************/
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bool Base64Decoder::decode( const char* & scursor, const char * const send,
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char* & dcursor, const char * const dend )
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{
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while ( dcursor != dend && scursor != send ) {
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uchar ch = *scursor++;
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uchar value;
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// try converting ch to a 6-bit value:
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if ( ch < 128 )
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value = base64DecodeMap[ ch ];
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else
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value = 64;
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// ch isn't of the base64 alphabet, check for other significant chars:
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if ( value >= 64 ) {
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if ( ch == '=' ) {
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// padding:
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if ( mStepNo == 0 || mStepNo == 1) {
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if (!mSawPadding) {
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// malformed
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kdWarning() << "Base64Decoder: unexpected padding "
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"character in input stream" << endl;
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}
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mSawPadding = true;
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break;
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} else if ( mStepNo == 2 ) {
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// ok, there should be another one
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} else if ( mStepNo == 3 ) {
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// ok, end of encoded stream
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mSawPadding = true;
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break;
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}
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mSawPadding = true;
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mStepNo = (mStepNo + 1) % 4;
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continue;
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} else {
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// non-base64 alphabet
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continue;
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}
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}
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if ( mSawPadding ) {
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kdWarning() << "Base64Decoder: Embedded padding character "
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"encountered!" << endl;
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return true;
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}
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// add the new bits to the output stream and flush full octets:
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switch ( mStepNo ) {
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case 0:
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mOutbits = value << 2;
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break;
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case 1:
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*dcursor++ = (char)(mOutbits | value >> 4);
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mOutbits = value << 4;
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break;
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case 2:
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*dcursor++ = (char)(mOutbits | value >> 2);
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mOutbits = value << 6;
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break;
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case 3:
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*dcursor++ = (char)(mOutbits | value);
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mOutbits = 0;
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break;
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default:
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assert( 0 );
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}
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mStepNo = (mStepNo + 1) % 4;
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}
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// return false when caller should call us again:
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return (scursor == send);
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} // Base64Decoder::decode()
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bool Base64Encoder::encode( const char* & scursor, const char * const send,
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char* & dcursor, const char * const dend ) {
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const uint maxPacketsPerLine = 76 / 4;
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// detect when the caller doesn't adhere to our rules:
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if ( mInsideFinishing ) return true;
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while ( scursor != send && dcursor != dend ) {
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// properly empty the output buffer before starting something new:
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// ### fixme: we can optimize this away, since the buffer isn't
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// written to anyway (most of the time)
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if ( mOutputBufferCursor && !flushOutputBuffer( dcursor, dend ) )
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return (scursor == send);
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uchar ch = *scursor++;
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// mNextbits // (part of) value of next sextet
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// check for line length;
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if ( mStepNo == 0 && mWrittenPacketsOnThisLine >= maxPacketsPerLine ) {
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writeCRLF( dcursor, dend );
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mWrittenPacketsOnThisLine = 0;
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}
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// depending on mStepNo, extract value and mNextbits from the
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// octet stream:
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switch ( mStepNo ) {
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case 0:
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assert( mNextbits == 0 );
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writeBase64( ch >> 2, dcursor, dend ); // top-most 6 bits -> output
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mNextbits = (ch & 0x3) << 4; // 0..1 bits -> 4..5 in mNextbits
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break;
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case 1:
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assert( (mNextbits & ~0x30) == 0 );
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writeBase64( mNextbits | ch >> 4, dcursor, dend ); // 4..7 bits -> 0..3 in value
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mNextbits = (ch & 0xf) << 2; // 0..3 bits -> 2..5 in mNextbits
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break;
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case 2:
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assert( (mNextbits & ~0x3C) == 0 );
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writeBase64( mNextbits | ch >> 6, dcursor, dend ); // 6..7 bits -> 0..1 in value
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writeBase64( ch & 0x3F, dcursor, dend ); // 0..5 bits -> output
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mNextbits = 0;
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mWrittenPacketsOnThisLine++;
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break;
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default:
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assert( 0 );
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}
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mStepNo = ( mStepNo + 1 ) % 3;
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}
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if ( mOutputBufferCursor ) flushOutputBuffer( dcursor, dend );
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return (scursor == send);
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}
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bool Rfc2047BEncodingEncoder::encode( const char* & scursor,
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const char * const send,
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char* & dcursor,
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const char * const dend )
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{
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// detect when the caller doesn't adhere to our rules:
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if ( mInsideFinishing ) return true;
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while ( scursor != send && dcursor != dend ) {
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// properly empty the output buffer before starting something new:
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// ### fixme: we can optimize this away, since the buffer isn't
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// written to anyway (most of the time)
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if ( mOutputBufferCursor && !flushOutputBuffer( dcursor, dend ) )
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return (scursor == send);
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uchar ch = *scursor++;
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// mNextbits // (part of) value of next sextet
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// depending on mStepNo, extract value and mNextbits from the
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// octet stream:
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switch ( mStepNo ) {
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case 0:
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assert( mNextbits == 0 );
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writeBase64( ch >> 2, dcursor, dend ); // top-most 6 bits -> output
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mNextbits = (ch & 0x3) << 4; // 0..1 bits -> 4..5 in mNextbits
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break;
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case 1:
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assert( (mNextbits & ~0x30) == 0 );
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writeBase64( mNextbits | ch >> 4, dcursor, dend ); // 4..7 bits -> 0..3 in value
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mNextbits = (ch & 0xf) << 2; // 0..3 bits -> 2..5 in mNextbits
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break;
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case 2:
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assert( (mNextbits & ~0x3C) == 0 );
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writeBase64( mNextbits | ch >> 6, dcursor, dend ); // 6..7 bits -> 0..1 in value
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writeBase64( ch & 0x3F, dcursor, dend ); // 0..5 bits -> output
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mNextbits = 0;
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break;
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default:
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assert( 0 );
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}
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mStepNo = ( mStepNo + 1 ) % 3;
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}
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if ( mOutputBufferCursor ) flushOutputBuffer( dcursor, dend );
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return (scursor == send);
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}
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bool Base64Encoder::finish( char* & dcursor, const char * const dend ) {
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return generic_finish( dcursor, dend, true );
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}
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bool Rfc2047BEncodingEncoder::finish( char* & dcursor,
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const char * const dend ) {
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return generic_finish( dcursor, dend, false );
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}
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bool Base64Encoder::generic_finish( char* & dcursor, const char * const dend,
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bool withLFatEnd )
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{
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if ( mInsideFinishing )
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return flushOutputBuffer( dcursor, dend );
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if ( mOutputBufferCursor && !flushOutputBuffer( dcursor, dend ) )
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return false;
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mInsideFinishing = true;
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//
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// writing out the last mNextbits...
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//
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switch ( mStepNo ) {
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case 1: // 2 mNextbits waiting to be written. Needs two padding chars:
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case 2: // 4 or 6 mNextbits waiting to be written. Completes a block
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writeBase64( mNextbits, dcursor, dend );
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mNextbits = 0;
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break;
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case 0: // no padding, nothing to be written, except possibly the CRLF
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assert( mNextbits == 0 );
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break;
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default:
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assert( 0 );
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}
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//
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// adding padding...
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//
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switch( mStepNo ) {
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case 1:
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write( '=', dcursor, dend );
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// fall through:
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case 2:
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write( '=', dcursor, dend );
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// fall through:
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case 0: // completed an quartet - add CRLF
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if ( withLFatEnd )
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writeCRLF( dcursor, dend );
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return flushOutputBuffer( dcursor, dend );
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default:
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assert( 0 );
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}
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return true; // asserts get compiled out
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}
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} // namespace KMime
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