//****************************************************************************
// fotplib.hpp
//	Contains functions for handling one-time pad (OTP) files.
//
// Notice
//	Copyright ©1995-97, David R. Tribble.
//
//	This source code is copyrighted.  Distribution of this source code is
//	granted, provided that this copyright notice remains attached to the
//	source code, and that adequate acknowledgement is given to the
//	original author.
//
// History
//	1.00 1995-05-03 dtribble.
//		First cut.
//	1.01 1995-06-27 dtribble.
//		Renamed "fotplib.h" to "fotplib.hpp".


#ifndef fotplib_hpp
#define fotplib_hpp	101


// Identification

#define FOTPLIB_ID_VERS	"1.01"
#define FOTPLIB_ID_DATE	"1995-05-27"

#ifndef NO_H_IDENT
static const char	id_fotp_h[] =
    "@(#)" FOTPLIB_ID_DATE " " FOTPLIB_ID_VERS " " __FILE__;
#endif


// System includes

#include <stdio.h>


// Local includes

#include "osdefs.h"


// Manifest constants

#define OTP_BLKSZ	(4 * 1024)	// OTP file block size


// Feedback mode types

#define OTP_FEEDBK_ECB	0		// ECB, none
#define OTP_FEEDBK_CBC	1		// CBC, cipher block chaining
#define OTP_FEEDBK_PBC	2		// PBC, plaintext block chaining
#define OTP_FEEDBK_CFB	3		// CFB, cipher feedback
#define OTP_FEEDBK_OFB	4		// OFB, output feedback
#define OTP_FEEDBK_PFB	5		// PFB, plaintext feedback


//----------------------------------------------------------------------------
// OTP file info

#define OTP_VERS	100		// Struct version
#define OTP_MAGIC	0x6FCB		// Struct magic number

class otp_file
{
private:
    unsigned short	o_magic;	// Magic number
    short		o_vers;		// Struct version

public:
    const char *	o_fname;	// File name
    FILE *		o_fp;		// File pointer
    long		o_off;		// Current offset

    unsigned char	o__r[64-12];	// Reserved, zero

    unsigned char	o_data[OTP_BLKSZ];
					// Current data block

public:
			otp_file();
			otp_file(const char *fname);

			~otp_file();

private:
    void		init();

public:
    int			open(const char *fname);
    int			close();

    int			seek(long off);
    int			readblk();
};


#endif // fotplib_hpp

// End fotplib.hpp