// SPDX-License-Identifier: LGPL-2.1-or-later

// Wild Magic Source Code
// David Eberly
// http://www.geometrictools.com
// Copyright (c) 1998-2007
//
// 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.  The license is available for reading at
// either of the locations:
//     http://www.gnu.org/copyleft/lgpl.html
//     http://www.geometrictools.com/License/WildMagicLicense.pdf
// The license applies to versions 0 through 4 of Wild Magic.
//
// Version: 4.0.0 (2006/06/28)

//----------------------------------------------------------------------------
namespace Wm4
{

template <class Real>
BandedMatrix<Real>::BandedMatrix (int iSize, int iLBands, int iUBands)
{
    assert(iSize > 0 && iLBands >= 0 && iUBands >= 0);
    assert(iLBands < iSize && iUBands < iSize);

    m_iSize = iSize;
    m_iLBands = iLBands;
    m_iUBands = iUBands;
    Allocate();
}
//----------------------------------------------------------------------------
template <class Real>
BandedMatrix<Real>::BandedMatrix (const BandedMatrix& rkM)
{
    m_afDBand = nullptr;
    m_aafLBand = nullptr;
    m_aafUBand = nullptr;
    *this = rkM;
}
//----------------------------------------------------------------------------
template <class Real>
BandedMatrix<Real>::~BandedMatrix ()
{
    Deallocate();
}
//----------------------------------------------------------------------------
template <class Real>
BandedMatrix<Real>& BandedMatrix<Real>::operator= (const BandedMatrix& rkM)
{
    Deallocate();
    m_iSize = rkM.m_iSize;
    m_iLBands = rkM.m_iLBands;
    m_iUBands = rkM.m_iUBands;
    Allocate();

    size_t uiSize = m_iSize*sizeof(Real);
    System::Memcpy(m_afDBand,uiSize,rkM.m_afDBand,uiSize);

    int i;
    for (i = 0; i < m_iLBands; i++)
    {
        uiSize = (m_iSize-1-i)*sizeof(Real);
        System::Memcpy(m_aafLBand[i],uiSize,rkM.m_aafLBand[i],uiSize);
    }

    for (i = 0; i < m_iUBands; i++)
    {
        uiSize = (m_iSize-1-i)*sizeof(Real);
        System::Memcpy(m_aafUBand[i],uiSize,rkM.m_aafUBand[i],uiSize);
    }

    return *this;
}
//----------------------------------------------------------------------------
template <class Real>
int BandedMatrix<Real>::GetSize () const
{
    return m_iSize;
}
//----------------------------------------------------------------------------
template <class Real>
int BandedMatrix<Real>::GetLBands () const
{
    return m_iLBands;
}
//----------------------------------------------------------------------------
template <class Real>
int BandedMatrix<Real>::GetUBands () const
{
    return m_iUBands;
}
//----------------------------------------------------------------------------
template <class Real>
Real* BandedMatrix<Real>::GetDBand ()
{
    return m_afDBand;
}
//----------------------------------------------------------------------------
template <class Real>
const Real* BandedMatrix<Real>::GetDBand () const
{
    return m_afDBand;
}
//----------------------------------------------------------------------------
template <class Real>
int BandedMatrix<Real>::GetLBandMax (int i) const
{
    assert(0 <= i && i < m_iLBands);
    return m_iSize-1-i;
}
//----------------------------------------------------------------------------
template <class Real>
Real* BandedMatrix<Real>::GetLBand (int i)
{
    if ( m_aafLBand )
    {
        assert(0 <= i && i < m_iLBands);
        return m_aafLBand[i];
    }
    return 0;
}
//----------------------------------------------------------------------------
template <class Real>
const Real* BandedMatrix<Real>::GetLBand (int i) const
{
    if (m_aafLBand)
    {
        assert(0 <= i && i < m_iLBands);
        return m_aafLBand[i];
    }
    return 0;
}
//----------------------------------------------------------------------------
template <class Real>
int BandedMatrix<Real>::GetUBandMax (int i) const
{
    assert(0 <= i && i < m_iUBands);
    return m_iSize-1-i;
}
//----------------------------------------------------------------------------
template <class Real>
Real* BandedMatrix<Real>::GetUBand (int i)
{
    if (m_aafUBand)
    {
        assert(0 <= i && i < m_iUBands);
        return m_aafUBand[i];
    }
    return 0;
}
//----------------------------------------------------------------------------
template <class Real>
const Real* BandedMatrix<Real>::GetUBand (int i) const
{
    if (m_aafUBand)
    {
        assert(0 <= i && i < m_iUBands);
        return m_aafUBand[i];
    }
    return 0;
}
//----------------------------------------------------------------------------
template <class Real>
Real& BandedMatrix<Real>::operator() (int iRow, int iCol)
{
    assert(0 <= iRow && iRow < m_iSize && 0 <= iCol && iCol < m_iSize);

    int iBand = iCol - iRow;
    if (iBand > 0)
    {
        if (--iBand < m_iUBands && iRow < m_iSize-1-iBand)
        {
            return m_aafUBand[iBand][iRow];
        }
    }
    else if ( iBand < 0 )
    {
        iBand = -iBand;
        if (--iBand < m_iLBands && iCol < m_iSize-1-iBand)
        {
            return m_aafLBand[iBand][iCol];
        }
    }
    else
    {
        return m_afDBand[iRow];
    }

    static Real s_fDummy = (Real)0.0;
    return s_fDummy;
}
//----------------------------------------------------------------------------
template <class Real>
Real BandedMatrix<Real>::operator() (int iRow, int iCol) const
{
    assert(0 <= iRow && iRow < m_iSize && 0 <= iCol && iCol < m_iSize);

    int iBand = iCol - iRow;
    if (iBand > 0)
    {
        if (--iBand < m_iUBands && iRow < m_iSize-1-iBand)
        {
            return m_aafUBand[iBand][iRow];
        }
    }
    else if ( iBand < 0 )
    {
        iBand = -iBand;
        if (--iBand < m_iLBands && iCol < m_iSize-1-iBand)
        {
            return m_aafLBand[iBand][iCol];
        }
    }
    else
    {
        return m_afDBand[iRow];
    }

    return (Real)0.0;
}
//----------------------------------------------------------------------------
template <class Real>
void BandedMatrix<Real>::SetZero ()
{
    assert(m_iSize > 0);

    memset(m_afDBand,0,m_iSize*sizeof(Real));

    int i;
    for (i = 0; i < m_iLBands; i++)
    {
        memset(m_aafLBand[i],0,(m_iSize-1-i)*sizeof(Real));
    }

    for (i = 0; i < m_iUBands; i++)
    {
        memset(m_aafUBand[i],0,(m_iSize-1-i)*sizeof(Real));
    }
}
//----------------------------------------------------------------------------
template <class Real>
void BandedMatrix<Real>::SetIdentity ()
{
    assert(m_iSize > 0);

    int i;
    for (i = 0; i < m_iSize; i++)
    {
        m_afDBand[i] = (Real)1.0;
    }

    for (i = 0; i < m_iLBands; i++)
    {
        memset(m_aafLBand[i],0,(m_iSize-1-i)*sizeof(Real));
    }

    for (i = 0; i < m_iUBands; i++)
    {
        memset(m_aafUBand[i],0,(m_iSize-1-i)*sizeof(Real));
    }
}
//----------------------------------------------------------------------------
template <class Real>
void BandedMatrix<Real>::Allocate ()
{
    // assert:  m_iSize, m_iLBands, m_iRBandQuantity already set
    // assert:  m_afDBand, m_aafLBand, m_aafUBand all null

    m_afDBand = WM4_NEW Real[m_iSize];
    memset(m_afDBand,0,m_iSize*sizeof(Real));

    if (m_iLBands > 0)
    {
        m_aafLBand = WM4_NEW Real*[m_iLBands];
    }
    else
    {
        m_aafLBand = nullptr;
    }

    if (m_iUBands > 0)
    {
        m_aafUBand = WM4_NEW Real*[m_iUBands];
    }
    else
    {
        m_aafUBand = nullptr;
    }

    int i;
    for (i = 0; i < m_iLBands; i++)
    {
        m_aafLBand[i] = WM4_NEW Real[m_iSize-1-i];
        memset(m_aafLBand[i],0,(m_iSize-1-i)*sizeof(Real));
    }

    for (i = 0; i < m_iUBands; i++)
    {
        m_aafUBand[i] = WM4_NEW Real[m_iSize-1-i];
        memset(m_aafUBand[i],0,(m_iSize-1-i)*sizeof(Real));
    }
}
//----------------------------------------------------------------------------
template <class Real>
void BandedMatrix<Real>::Deallocate ()
{
    WM4_DELETE[] m_afDBand;

    int i;

    if (m_aafLBand)
    {
        for (i = 0; i < m_iLBands; i++)
        {
            WM4_DELETE[] m_aafLBand[i];
        }

        WM4_DELETE[] m_aafLBand;
        m_aafLBand = nullptr;
    }

    if (m_aafUBand)
    {
        for (i = 0; i < m_iUBands; i++)
        {
            WM4_DELETE[] m_aafUBand[i];
        }

        WM4_DELETE[] m_aafUBand;
        m_aafUBand = nullptr;
    }
}
//----------------------------------------------------------------------------
} // namespace Wm4