base64.h

来自「open lattice boltzmann project www.open」· C头文件 代码 · 共 82 行

/*  This file is part of the OpenLB library
 *
 *  Copyright (C) 2007 Jonas Latt
 *  Address: Rue General Dufour 24,  1211 Geneva 4, Switzerland 
 *  E-mail: [e-mail]
 *
 *  This program is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU General Public License
 *  as published by the Free Software Foundation; either version 2
 *  of the License, or (at your option) any later version.
 *
 *  This program 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 program; if not, write to the Free 
 *  Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 *  Boston, MA  02110-1301, USA.
*/

/* Acknowledgment: The strategy adopted here to encode
 * and decode Base64, and in particular the expression of the
 * arrays Base64Encoder::enc64 and Base64Decoder::dec64, 
 * is inspired by the open source library b64 by Bob Trower,
 * which is distributed with a MIT license at the address
 * http://base64.sourceforge.net/b64.c
 */


#ifndef BASE64_H
#define BASE64_H

#include <iosfwd>

namespace olb {

template<typename T>
class Base64Encoder {
public:
    Base64Encoder(std::ostream& ostr_, size_t fullLength_);
    void encode(const T* data, size_t length);
private:
    void fillOverflow(const unsigned char* charData, size_t charLength, size_t& pos);
    void flushOverflow();
    void writeSize();
    void encodeBlock( const unsigned char* data);
    void encodeUnfinishedBlock( const unsigned char* data, int length);
private:
    static const char enc64[65];
private:
    std::ostream& ostr;
    size_t charFullLength;
    size_t numWritten;
    int numOverflow;
    unsigned char overflow[3];
};

template<typename T>
class Base64Decoder {
public:
    Base64Decoder(std::istream& istr_, size_t fullLength_);
    void decode(T* data, size_t length);
private:
    void flushOverflow(unsigned char* charData, size_t charLength, size_t& pos);
    unsigned char getNext();
    void decodeBlock(unsigned char* data);
private:
    static const char dec64[82];
private:
    std::istream& istr;
    size_t charFullLength;
    size_t numRead;
    int posOverflow;
    unsigned char overflow[3];
};

} // namespace olb

#endif