/*****************************************************************************
 * Author:   Valient Gough <vgough@pobox.com>
 *
 *****************************************************************************
 * Copyright (c) 2004, Valient Gough
 *
 * This program is free software: you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as published by the
 * Free Software Foundation, either version 3 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 Lesser General Public License
 * for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#ifndef _CipherFileIO_incl_
#define _CipherFileIO_incl_

#include "BlockFileIO.h"
#include "CipherKey.h"
#include "FileUtils.h"

#if defined(HAVE_INTTYPES_H)
#include <inttypes.h>
#endif

#if defined(HAVE_STDINT_H)
#include <stdint.h>
#endif

class Cipher;

/*
    Implement the FileIO interface encrypting data in blocks. 
    
    Uses BlockFileIO to handle the block scatter / gather issues.
*/
class CipherFileIO : public BlockFileIO
{
public:
    CipherFileIO( const boost::shared_ptr<FileIO> &base, 
                  const FSConfigPtr &cfg);
    virtual ~CipherFileIO();

    virtual rel::Interface get_interface() const;

    virtual void setFileName( const char *fileName );
    virtual const char *getFileName() const;
    virtual bool setIV( uint64_t iv );

    virtual int open( int flags );

    virtual int getAttr( efs_stat *stbuf, void *statCache ) const;
    virtual efs_off_t getSize() const;

    virtual int truncate( efs_off_t size );

    virtual bool isWritable() const;

private:
    virtual ssize_t readOneBlock( const IORequest &req ) const;
    virtual bool writeOneBlock( const IORequest &req );

    void initHeader();
    bool writeHeader();
    bool blockRead( unsigned char *buf, int size, 
	             uint64_t iv64 ) const;
    bool streamRead( unsigned char *buf, int size, 
	             uint64_t iv64 ) const;
    bool blockWrite( unsigned char *buf, int size, 
	             uint64_t iv64 ) const;
    bool streamWrite( unsigned char *buf, int size, 
	             uint64_t iv64 ) const;

    boost::shared_ptr<FileIO> base;

    FSConfigPtr fsConfig;

    // if haveHeader is true, then we have a transparent file header which
    // contains a 64 bit initialization vector.
    bool haveHeader;
    bool externalIVChaining;
    uint64_t externalIV;
    uint64_t fileIV;
    int lastFlags;

    boost::shared_ptr<Cipher> cipher;
    CipherKey key;
};

#endif
