/* This file is part of the wvWare 2 project
   Copyright (C) 2002-2003 Werner Trobin <trobin@kde.org>

   This library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Library General Public
   License version 2 as published by the Free Software Foundation.

   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
   Library General Public License for more details.

   You should have received a copy of the GNU Library General Public License
   along with this library; see the file COPYING.LIB.  If not, write to
   the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
   Boston, MA 02111-1307, USA.
*/

#include "headers97.h"

using namespace wvWare;

Headers97::Headers97( U32 ccpHdd, U32 fcPlcfhdd, U32 lcbPlcfhdd, OLEStreamReader* tableStream ) :
    Headers( ccpHdd, fcPlcfhdd, lcbPlcfhdd, tableStream, Word8 )
{
}

std::pair<U32, U32> Headers97::findHeader( int sectionNumber, unsigned char mask ) const
{
    // NOTE: An empty header/footer story specifies that the previous section's
    // header/footer of the corresponding type is used.  For the first section,
    // an empty header/footer story specifies that it does not have a
    // header/footer of this type.  MS-DOC, p.34

    U32 start = 0;
    U32 lim = 0;
    const int offset = maskToOffset( mask );
    do {
        const int tmp = sectionNumber * headerTypes + offset;
        start = m_headers[ tmp ];
        lim = m_headers[ tmp + 1 ];
        --sectionNumber;
    } while ( start == lim && sectionNumber >= 0 );

    return std::make_pair( start, lim );
}

int Headers97::maskToOffset( unsigned char mask ) const
{
    int offset = 0;
    while ( mask != 0 && ( mask & 1 ) == 0 ) {
        ++offset;
        mask >>= 1;
    }
    return offset;
}
