/* This file is part of the KDE libraries
   Copyright (C) 2001, 2002, 2007 David Faure <faure@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 02110-1301, USA.
*/

#include "klimitediodevice_p.h"
#include "loggingcategory.h"

KLimitedIODevice::KLimitedIODevice(QIODevice *dev, qint64 start, qint64 length)
    : m_dev(dev)
    , m_start(start)
    , m_length(length)
{
    //qCDebug(KArchiveLog) << "start=" << start << "length=" << length;
    open(QIODevice::ReadOnly);   //krazy:exclude=syscalls
}

bool KLimitedIODevice::open(QIODevice::OpenMode m)
{
    //qCDebug(KArchiveLog) << "m=" << m;
    if (m & QIODevice::ReadOnly) {
        /*bool ok = false;
          if ( m_dev->isOpen() )
          ok = ( m_dev->mode() == QIODevice::ReadOnly );
          else
          ok = m_dev->open( m );
          if ( ok )*/
        m_dev->seek(m_start);   // No concurrent access !
    } else {
        //qCWarning(KArchiveLog) << "KLimitedIODevice::open only supports QIODevice::ReadOnly!";
    }
    setOpenMode(QIODevice::ReadOnly);
    return true;
}

void KLimitedIODevice::close()
{
}

qint64 KLimitedIODevice::size() const
{
    return m_length;
}

qint64 KLimitedIODevice::readData(char *data, qint64 maxlen)
{
    maxlen = qMin(maxlen, m_length - pos());   // Apply upper limit
    return m_dev->read(data, maxlen);
}

bool KLimitedIODevice::seek(qint64 pos)
{
    Q_ASSERT(pos <= m_length);
    pos = qMin(pos, m_length);   // Apply upper limit
    bool ret = m_dev->seek(m_start + pos);
    if (ret) {
        QIODevice::seek(pos);
    }
    return ret;
}

qint64 KLimitedIODevice::bytesAvailable() const
{
    return QIODevice::bytesAvailable();
}

bool KLimitedIODevice::isSequential() const
{
    return m_dev->isSequential();
}
