/*
   JAMLIB - A JAM subroutine library
   Copyright (C) 1999 Björn Stenberg

   This library 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 2.1 of the License, or (at your option) any later version.

   This library 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 library; if not, write to the Free Software
   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

   Changes made by Johan Billing 2000-04-16:

   - Changed source to use feof() instead of errno == EPASTEOF
   - Changed source to use structrw to read and write structures
   */

/***********************************************************************
 **
 **  LASTREAD.C -- Lastread pointer handling
 **
 **  Author: Bj”rn Stenberg (bjorn.stenberg@sth.frontec.se)
 **
 ***********************************************************************/
#ifdef HAVE_CONFIG_H
# include <config.h>
#endif

#include <stdio.h>
#include <errno.h>

#include <jamlib/jam.h>
#include "structrw.h"

/***********************************************************************
 **
 **  JAM_ReadLastRead - Read LastRead record {{{
 **/
int JAM_ReadLastRead( s_JamBase*	Base_PS,
		      ulong		User_I,
		      s_JamLastRead*	Record_PS )
{
    s_JamLastRead Record_S;
    int Pos_I;

    if (!Record_PS)
	return JAM_BAD_PARAM;

    if ( fseek( Base_PS->LrdFile_PS, 0, SEEK_SET ) ) {
	Base_PS->Errno_I = errno;
	return JAM_IO_ERROR;
    }

    for ( Pos_I = 0; ; Pos_I++ ) {

	if ( 1 > freadjamlastread(Base_PS->LrdFile_PS,&Record_S) ) {
	    if ( feof(Base_PS->LrdFile_PS) )
		return JAM_NO_USER;
	    Base_PS->Errno_I = errno;
	    return JAM_IO_ERROR;
	}

	if ( Record_S.UserID == User_I ) {
	    Base_PS->LastUserPos_I  = Pos_I;
	    Base_PS->LastUserId_I = User_I;
	    *Record_PS = Record_S;
	    return 0;
	}
    }

    return 0;
}
/** }}}
 **
 ***********************************************************************/

/***********************************************************************
 **
 **  JAM_WriteLastRead - Write LastRead record {{{
 **/
int JAM_WriteLastRead( s_JamBase*	Base_PS,
		       ulong		User_I,
		       s_JamLastRead*	Record_PS )
{
    s_JamLastRead Record_S;
    int Pos_I;

    if (!Record_PS)
	return JAM_BAD_PARAM;

    /* if the last read is stored {{{ */
    if ( User_I == Base_PS->LastUserId_I ) {
	Pos_I = Base_PS->LastUserPos_I * sizeof( s_JamLastRead );

	if ( fseek( Base_PS->LrdFile_PS, Pos_I, SEEK_SET ) ) {
	    Base_PS->Errno_I = errno;
	    return JAM_IO_ERROR;
	}

	/* be safe, check it */
	if ( 1 > freadjamlastread(Base_PS->LrdFile_PS,&Record_S) ) {
	    Base_PS->Errno_I = errno;
	    return JAM_IO_ERROR;
	}

	/* is it where we expected it to be? {{{ */
	if ( User_I == Record_S.UserID ) {

	    if ( fseek( Base_PS->LrdFile_PS, Pos_I, SEEK_SET ) ) {
		Base_PS->Errno_I = errno;
		return JAM_IO_ERROR;
	    }

	    if ( 1 > fwritejamlastread(Base_PS->LrdFile_PS,Record_PS) ) {
		Base_PS->Errno_I = errno;
		return JAM_IO_ERROR;
	    }

	    fflush(Base_PS -> LrdFile_PS);

	    return 0;
	} /* }}} */
    } /* }}} */

    /* no last position, or position incorrect */
    if ( fseek( Base_PS->LrdFile_PS, 0, SEEK_SET ) ) {
	Base_PS->Errno_I = errno;
	return JAM_IO_ERROR;
    }

    for ( Pos_I = 0; ; Pos_I++ ) {

	if ( 1 > freadjamlastread(Base_PS->LrdFile_PS,&Record_S) ) {
	    if ( feof(Base_PS->LrdFile_PS) ) {

		/* user not in file, append a new record  */
		if ( fseek( Base_PS->LrdFile_PS, 0, SEEK_END ) ) {
		    Base_PS->Errno_I = errno;
		    return JAM_IO_ERROR;
		}
		break;
	    }
	    Base_PS->Errno_I = errno;
	    return JAM_IO_ERROR;
	}

	/* found the user? */
	if ( Record_S.UserID == User_I ) {
	    if ( fseek( Base_PS->LrdFile_PS, Pos_I * sizeof(s_JamLastRead), SEEK_SET ) ) {
		Base_PS->Errno_I = errno;
		return JAM_IO_ERROR;
	    }
	    break;
	}
    }

    if ( 1 > fwritejamlastread(Base_PS->LrdFile_PS,Record_PS) ) {
	Base_PS->Errno_I = errno;
	return JAM_IO_ERROR;
    }

    fflush( Base_PS->LrdFile_PS );

    return 0;
}
/** }}}
 **
 ***********************************************************************/
/* Local variables:
 * vim:set ts=8 sts=4 sw=4:
 * vim600:fdm=marker:
 */