/*---------------------------------------------------------------------------*\
  =========                 |
  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
   \\    /   O peration     |
    \\  /    A nd           | Copyright (C) 1991-2010 OpenCFD Ltd.
     \\/     M anipulation  |
-------------------------------------------------------------------------------
License
    This file is part of OpenFOAM.

    OpenFOAM is free software: you can redistribute it and/or modify it
    under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    OpenFOAM 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 General Public License
    for more details.

    You should have received a copy of the GNU General Public License
    along with OpenFOAM.  If not, see <http://www.gnu.org/licenses/>.

\*---------------------------------------------------------------------------*/

#include "error.H"

#include "DLListBase.H"
#include "IOstreams.H"
#include "long.H"

// * * * * * * * * * * * * * * Static Data Members * * * * * * * * * * * * * //

Foam::DLListBase::iterator Foam::DLListBase::endIter_
(
    const_cast<DLListBase&>(static_cast<const DLListBase&>(DLListBase()))
);

Foam::DLListBase::const_iterator Foam::DLListBase::endConstIter_
(
    static_cast<const DLListBase&>(DLListBase()),
    reinterpret_cast<const link*>(0)
);


// * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //

void Foam::DLListBase::insert(DLListBase::link* a)
{
    nElmts_++;

    if (!first_)
    {
        a->prev_ = a;
        a->next_ = a;
        first_ = last_ = a;
    }
    else
    {
        a->prev_ = a;
        a->next_ = first_;
        first_->prev_ = a;
        first_ = a;
    }
}


void Foam::DLListBase::append(DLListBase::link* a)
{
    nElmts_++;

    if (!first_)
    {
        a->prev_ = a;
        a->next_ = a;
        first_ = last_ = a;
    }
    else
    {
        last_->next_ = a;
        a->prev_ = last_;
        a->next_ = a;
        last_ = a;
    }
}


bool Foam::DLListBase::swapUp(DLListBase::link* a)
{
    if (first_ != a)
    {
        link* ap = a->prev_;

        if (ap == first_)
        {
            first_ = a;
        }

        if (a == last_)
        {
            last_ = ap;
        }

        if (a->next_)
        {
            a->next_->prev_ = ap;
        }

        if (ap->prev_)
        {
            ap->prev_->next_ = a;
        }

        a->prev_ = ap->prev_;
        ap->prev_ = a;

        ap->next_ = a->next_;
        a->next_ = ap;

        return true;
    }
    else
    {
        return false;
    }
}


bool Foam::DLListBase::swapDown(DLListBase::link* a)
{
    if (last_ != a)
    {
        link* an = a->next_;

        if (a == first_)
        {
            first_ = an;
        }

        if (an == last_)
        {
            last_ = a;
        }

        if (a->prev_)
        {
            a->prev_->next_ = an;
        }

        if (an->next_)
        {
            an->next_->prev_ = a;
        }

        an->prev_ = a->prev_;
        a->prev_ = an;

        a->next_ = an->next_;
        an->next_ = a;

        return true;
    }
    else
    {
        return false;
    }
}


Foam::DLListBase::link* Foam::DLListBase::removeHead()
{
    nElmts_--;

    if (!first_)
    {
        FatalErrorIn("void DLListBase::removeHead()")
            << "remove from empty list"
            << abort(FatalError);
    }

    DLListBase::link* f = first_;
    first_ = f->next_;

    if (!first_)
    {
        last_ = 0;
    }

    f->deregister();
    return f;
}


Foam::DLListBase::link* Foam::DLListBase::remove(DLListBase::link* l)
{
    nElmts_--;

    link* ret = l;

    if (l == first_ && first_ == last_)
    {
        first_ = 0;
        last_ = 0;
    }
    else if (l == first_)
    {
        first_ = first_->next_;
        first_->prev_ = first_;
    }
    else if (l == last_)
    {
        last_ = last_->prev_;
        last_->next_ = last_;
    }
    else
    {
        l->next_->prev_ = l->prev_;
        l->prev_->next_ = l->next_;
    }

    ret->deregister();
    return ret;
}


Foam::DLListBase::link* Foam::DLListBase::replace
(
    DLListBase::link* oldLink,
    DLListBase::link* newLink
)
{
    link* ret = oldLink;

    newLink->prev_ = oldLink->prev_;
    newLink->next_ = oldLink->next_;

    if (oldLink == first_ && first_ == last_)
    {
        first_ = newLink;
        last_  = newLink;
    }
    else if (oldLink == first_)
    {
        first_ = newLink;
        newLink->next_->prev_ = newLink;
    }
    else if (oldLink == last_)
    {
        last_ = newLink;
        newLink->prev_->next_ = newLink;
    }
    else
    {
        newLink->prev_->next_ = newLink;
        newLink->next_->prev_ = newLink;
    }

    ret->deregister();
    return ret;
}


// ************************************************************************* //