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/*************************************************************************
 *
 *  OpenOffice.org - a multi-platform office productivity suite
 *
 *  $RCSfile: packedpixeliterator.hxx,v $
 *
 *  $Revision: 1.2 $
 *
 *  last change: $Author: thb $ $Date: 2006-05-31 10:12:12 $
 *
 *  The Contents of this file are made available subject to
 *  the terms of GNU Lesser General Public License Version 2.1.
 *
 *
 *    GNU Lesser General Public License Version 2.1
 *    =============================================
 *    Copyright 2005 by Sun Microsystems, Inc.
 *    901 San Antonio Road, Palo Alto, CA 94303, USA
 *
 *    This library is free software; you can redistribute it and/or
 *    modify it under the terms of the GNU Lesser General Public
 *    License version 2.1, 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
 *    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
 *
 ************************************************************************/

#ifndef INCLUDED_BASEBMP_PACKEDPIXELITERATOR_HXX
#define INCLUDED_BASEBMP_PACKEDPIXELITERATOR_HXX

#include "metafunctions.hxx"
#include "stridedarrayiterator.hxx"

#include <boost/static_assert.hpp>
#include <vigra/metaprogramming.hxx>
#include <vigra/diff2d.hxx>

namespace basebmp
{

/// Get bitmask for data at given intra-word position, for given bit depth
template< typename data_type, int bits_per_pixel, bool MsbFirst, typename difference_type > inline data_type get_mask( difference_type d )
{
    BOOST_STATIC_ASSERT(bits_per_pixel > 0);
    BOOST_STATIC_ASSERT(sizeof(data_type)*8 % bits_per_pixel == 0);
    BOOST_STATIC_ASSERT(sizeof(data_type)*8 / bits_per_pixel > 1);
    BOOST_STATIC_ASSERT(vigra::TypeTraits<data_type>::isPOD::asBool);

    const unsigned int nIntraWordPositions( sizeof(data_type)*8 / bits_per_pixel );

    //      create bits_per_pixel 1s      shift to intra-word position
    return ((~(~0 << bits_per_pixel)) << bits_per_pixel*(MsbFirst ?
                                                         (nIntraWordPositions-1 - (d % nIntraWordPositions)) :
                                                         (d % nIntraWordPositions)));
}

template< int num_intraword_positions, int bits_per_pixel, bool MsbFirst, typename difference_type > inline difference_type get_shift( difference_type remainder )
{
    return bits_per_pixel*(MsbFirst ?
                           (num_intraword_positions - 1 - remainder) :
                           remainder);
}

template< typename Datatype,
          typename Valuetype,
          int      bits_per_pixel,
          bool     MsbFirst > class PackedPixelColumnIterator
{
public:
    // no reference, no index_reference type here
    typedef Datatype                                    data_type;
    typedef Valuetype                                   value_type;
    typedef int                                         difference_type;
    typedef image_traverser_tag                         iterator_category;

    typedef typename remove_const<data_type>::type      mask_type;
    typedef data_type*                                  pointer;
    typedef StridedArrayIterator< data_type >           MoveY;

    enum {
        /** The number of pixel within a single data_type value
         */
        num_intraword_positions=sizeof(data_type)*8/bits_per_pixel,
        /** Bit mask for one pixel (least significant bits)
         */
        bit_mask=~(~0 << bits_per_pixel)
    };

private:
    MoveY           y;
    mask_type       mask_;
    difference_type shift_;

    void inc()
    {
        ++y;
    }

    void dec()
    {
        --y;
    }

    bool equal( PackedPixelColumnIterator const & rhs ) const
    {
        return rhs.y == y;
    }

    bool less( PackedPixelColumnIterator const & rhs ) const
    {
        return y < rhs.y;
    }

public:
    PackedPixelColumnIterator() :
        y(0),
        mask_( get_mask<data_type, bits_per_pixel, MsbFirst, difference_type>(0) ),
        shift_( get_shift<num_intraword_positions, bits_per_pixel, MsbFirst, difference_type>(0) )
    {}

    PackedPixelColumnIterator( const MoveY& base, difference_type remainder ) :
        y(base),
        mask_( get_mask<data_type, bits_per_pixel, MsbFirst>(remainder) ),
        shift_( get_shift<num_intraword_positions, bits_per_pixel, MsbFirst>(remainder) )
    {}

    PackedPixelColumnIterator& operator+=( difference_type d )
    {
        y += d;
        return *this;
    }

    PackedPixelColumnIterator& operator-=( difference_type d )
    {
        y -= d;
        return *this;
    }

    PackedPixelColumnIterator operator+( difference_type d )
    {
        PackedPixelColumnIterator res(*this);
        res += d;
        return res;
    }

    PackedPixelColumnIterator operator-( difference_type d )
    {
        PackedPixelColumnIterator res(*this);
        res -= d;
        return res;
    }

    PackedPixelColumnIterator& operator++()
    {
        inc();
        return *this;
    }

    PackedPixelColumnIterator& operator--()
    {
        dec();
        return *this;
    }

    PackedPixelColumnIterator operator++(int)
    {
        PackedPixelColumnIterator res(*this);
        inc();
        return res;
    }

    PackedPixelColumnIterator operator--(int)
    {
        PackedPixelColumnIterator res(*this);
        dec();
        return res;
    }

    bool operator==(PackedPixelColumnIterator const & rhs) const
    {
        return equal( rhs );
    }

    bool operator!=(PackedPixelColumnIterator const & rhs) const
    {
        return !equal( rhs );
    }

    bool operator<(PackedPixelColumnIterator const & rhs) const
    {
        return less(rhs);
    }

    bool operator<=(PackedPixelColumnIterator const & rhs) const
    {
        return !less(rhs);
    }

    bool operator>(PackedPixelColumnIterator const & rhs) const
    {
        return rhs.less(*this);
    }

    bool operator>=(PackedPixelColumnIterator const & rhs) const
    {
        return !rhs.less(*this);
    }

    difference_type operator-(PackedPixelColumnIterator const & rhs) const
    {
        return y - rhs.y;
    }

    value_type get() const
    {
        // TODO(Q3): use traits to get unsigned type for data_type (if
        // not already)
        return static_cast<unsigned int>(*y() & mask_) >> shift_;
    }

    value_type get(difference_type d) const
    {
        // TODO(Q3): use traits to get unsigned type for data_type (if
        // not already)
        return static_cast<unsigned int>(*y(d) & mask_) >> shift_;
    }

    void set( value_type v ) const
    {
        const value_type pixel_value( (v << shift_) & mask_ );
        *y() = (*y() & ~mask_) | pixel_value;
    }

    void set( value_type v, difference_type d ) const
    {
        const value_type pixel_value( (v << shift_) & mask_ );
        *y(d) = (*y(d) & ~mask_) | pixel_value;
    }
};

template< typename Datatype,
          typename Valuetype,
          int      bits_per_pixel,
          bool     MsbFirst > class PackedPixelRowIterator
{
public:
    // no reference, no index_reference type here
    typedef Datatype                                    data_type;
    typedef Valuetype                                   value_type;
    typedef int                                         difference_type;
    typedef image_traverser_tag                         iterator_category;

    typedef typename remove_const<data_type>::type      mask_type;
    typedef data_type*                                  pointer;

    enum {
        /** The number of pixel within a single data_type value
         */
        num_intraword_positions=sizeof(data_type)*8/bits_per_pixel,
        /** Bit mask for one pixel (least significant bits)
         */
        bit_mask=~(~0 << bits_per_pixel)
    };

private:
    pointer         data_;
    mask_type       mask_;
    difference_type remainder_;

    void update_mask()
    {
        mask_ = get_mask<data_type, bits_per_pixel, MsbFirst>(remainder_);
    }

    void inc()
    {
        const difference_type newValue( remainder_ + 1 );
        const difference_type data_offset( newValue / num_intraword_positions );

        data_ += data_offset;
        remainder_ = newValue % num_intraword_positions;

        const mask_type shifted_mask(
            MsbFirst ?
            // TODO(Q3): use traits to get unsigned type for data_type
            // (if not already)
            static_cast<unsigned int>(mask_) >> bits_per_pixel :
            mask_ << bits_per_pixel );

        // data_offset is 0 for shifted mask, and 1 for wrapped-around mask
        mask_ = (1-data_offset)*shifted_mask + data_offset*(MsbFirst ?
                                                            bit_mask << bits_per_pixel*(num_intraword_positions-1) :
                                                            bit_mask);
    }

    void dec()
    {
        const difference_type newValue( remainder_ - 1 );
        const bool            isNegative( is_negative(newValue) );
        const difference_type newRemainder( newValue % num_intraword_positions );

        // calc  data_ += newValue / num_intraword_positions;
        //       remainder_ = newRemainder;
        // for newValue >= 0, and
        //       data_ += newValue / num_intraword_positions - 1;
        //       remainder_ = num_intraword_positions - newRemainder;
        // (to force remainder_ to be positive).
        // This is branch-free, if is_negative() is branch-free
        const difference_type data_offset( newValue / num_intraword_positions - isNegative );
        data_     += data_offset;
        remainder_ = newRemainder + isNegative*num_intraword_positions;

        const mask_type shifted_mask(
            MsbFirst ?
            mask_ << bits_per_pixel :
            // TODO(Q3): use traits to get unsigned type for data_type
            // (if not already)
            static_cast<unsigned int>(mask_) >> bits_per_pixel );

        // data_offset is 0 for shifted mask, and 1 for wrapped-around mask
        mask_ = (1-data_offset)*shifted_mask + data_offset*(MsbFirst ?
                                                            bit_mask :
                                                            bit_mask << bits_per_pixel*(num_intraword_positions-1));
    }

    bool equal( PackedPixelRowIterator const & rhs ) const
    {
        return rhs.data_ == data_ && rhs.remainder_ == remainder_;
    }

    bool less( PackedPixelRowIterator const & rhs ) const
    {
        return data_ == rhs.data_ ?
            (remainder_ < rhs.remainder_) :
            (data_ < rhs.data_);
    }

public:
    PackedPixelRowIterator() :
        data_(0),
        mask_( get_mask<data_type, bits_per_pixel, MsbFirst, difference_type>(0) ),
        remainder_(0)
    {}

    explicit PackedPixelRowIterator( pointer base, int x ) :
        data_(base),
        mask_(0),
        remainder_(x % num_intraword_positions)
    {
        update_mask();
    }

    PackedPixelRowIterator& operator+=( difference_type d )
    {
        const difference_type newValue( remainder_ + d );

        data_ += newValue / num_intraword_positions;
        remainder_ = newValue % num_intraword_positions;
        update_mask();

        return *this;
    }

    PackedPixelRowIterator& operator-=( difference_type d )
    {
        const difference_type newValue( remainder_ - d );
        const bool            isNegative( is_negative(newValue) );
        const difference_type newRemainder( newValue % num_intraword_positions );

        // calc  data_ += newValue / num_intraword_positions;
        //       remainder_ = newRemainder;
        // for newValue >= 0, and
        //       data_ += newValue / num_intraword_positions - 1;
        //       remainder_ = num_intraword_positions - newRemainder;
        // (to force remainder_ to be positive).
        // This is branch-free, if is_negative() is branch-free
        data_     += newValue / num_intraword_positions - isNegative;
        remainder_ = newRemainder + isNegative*(num_intraword_positions - 2*newRemainder);
        update_mask();

        return *this;
    }

    PackedPixelRowIterator operator+( difference_type d )
    {
        PackedPixelRowIterator res(*this);
        res += d;
        return res;
    }

    PackedPixelRowIterator operator-( difference_type d )
    {
        PackedPixelRowIterator res(*this);
        res -= d;
        return res;
    }

    PackedPixelRowIterator& operator++()
    {
        inc();
        return *this;
    }

    PackedPixelRowIterator& operator--()
    {
        dec();
        return *this;
    }

    PackedPixelRowIterator operator++(int)
    {
        PackedPixelRowIterator res(*this);
        inc();
        return res;
    }

    PackedPixelRowIterator operator--(int)
    {
        PackedPixelRowIterator res(*this);
        dec();
        return res;
    }

    bool operator==(PackedPixelRowIterator const & rhs) const
    {
        return equal( rhs );
    }

    bool operator!=(PackedPixelRowIterator const & rhs) const
    {
        return !equal( rhs );
    }

    bool operator<(PackedPixelRowIterator const & rhs) const
    {
        return less(rhs);
    }

    bool operator<=(PackedPixelRowIterator const & rhs) const
    {
        return !less(rhs);
    }

    bool operator>(PackedPixelRowIterator const & rhs) const
    {
        return rhs.less(*this);
    }

    bool operator>=(PackedPixelRowIterator const & rhs) const
    {
        return !rhs.less(*this);
    }

    difference_type operator-(PackedPixelRowIterator const & rhs) const
    {
        return (data_ - rhs.data_)*num_intraword_positions + (remainder_ - rhs.remainder_);
    }

    value_type get() const
    {
        // TODO(Q3): use traits to get unsigned type for data_type (if
        // not already)
        return static_cast<unsigned int>(*data_ & mask_) >>
            get_shift<num_intraword_positions, bits_per_pixel, MsbFirst>(remainder_);
    }

    value_type get(difference_type d) const
    {
        PackedPixelRowIterator tmp(*this);
        tmp += d;
        return tmp.get();
    }

    void set( value_type v ) const
    {
        const value_type pixel_value(
            (v <<
             get_shift<num_intraword_positions, bits_per_pixel, MsbFirst>(remainder_))
            & mask_ );
        *data_ = (*data_ & ~mask_) | pixel_value;
    }

    void set( value_type v, difference_type d ) const
    {
        PackedPixelRowIterator tmp(*this);
        tmp += d;
        tmp.set(v);
    }
};

template< typename Datatype,
          typename Valuetype,
          int      bits_per_pixel,
          bool     MsbFirst > class PackedPixelIterator
{
public:
    // no reference, no index_reference type here
    typedef Datatype                                    data_type;
    typedef Valuetype                                   value_type;
    typedef vigra::Diff2D                               difference_type;
    typedef image_traverser_tag                         iterator_category;
    typedef PackedPixelRowIterator<data_type,
                                   value_type,
                                   bits_per_pixel,
                                   MsbFirst>            row_iterator;
    typedef PackedPixelColumnIterator<data_type,
                                      value_type,
                                      bits_per_pixel,
                                      MsbFirst>         column_iterator;

    typedef data_type*                                  pointer;
    typedef int                                         MoveX;
    typedef StridedArrayIterator< data_type >           MoveY;

    enum {
        /** The number of pixel within a single data_type value
         */
        num_intraword_positions=sizeof(data_type)*8/bits_per_pixel,
        /** Bit mask for one pixel (least significant bits)
         */
        bit_mask=~(~0 << bits_per_pixel)
    };

    // TODO(F2): direction of iteration (ImageIterator can be made to
    // run backwards)

private:
    pointer current() const
    {
        return y() + (x / num_intraword_positions);
    }

    pointer current(int dx, int dy) const
    {
        return y(dy) + ((x+dx)/num_intraword_positions);
    }

    bool equal(PackedPixelIterator const & rhs) const
    {
        return (x == rhs.x) && (y == rhs.y);
    }

public:
    PackedPixelIterator() :
        x(0),
        y(0)
    {}

    PackedPixelIterator(pointer base, int ystride) :
        x(0),
        y(ystride,base)
    {}

    bool operator==(PackedPixelIterator const & rhs) const
    {
        return equal(rhs);
    }

    bool operator!=(PackedPixelIterator const & rhs) const
    {
        return !equal(rhs);
    }

    difference_type operator-(PackedPixelIterator const & rhs) const
    {
        return difference_type(x - rhs.x, y - rhs.y);
    }

    MoveX x;
    MoveY y;

    PackedPixelIterator & operator+=(difference_type const & s)
    {
        x += s.x;
        y += s.y;
        return *this;
    }

    PackedPixelIterator & operator-=(difference_type const & s)
    {
        x -= s.x;
        y -= s.y;
        return *this;
    }

    PackedPixelIterator operator+(difference_type const & s) const
    {
        PackedPixelIterator ret(*this);
        ret += s;
        return ret;
    }

    PackedPixelIterator operator-(difference_type const & s) const
    {
        PackedPixelIterator ret(*this);
        ret -= s;
        return ret;
    }

    row_iterator rowIterator() const
    {
        return row_iterator(current(),x);
    }

    column_iterator columnIterator() const
    {
        return column_iterator(MoveY(y,
                                     x / num_intraword_positions),
                               x % num_intraword_positions);
    }

    value_type get() const
    {
        const int remainder( x % num_intraword_positions );

        // TODO(Q3): use traits to get unsigned type for data_type (if
        // not already)
        value_type nTmp0( *current() );
        unsigned int nTmp1(static_cast<unsigned int>(*current() &
                                                     get_mask<data_type, bits_per_pixel, MsbFirst>(remainder)));
        unsigned int nTmp2( (static_cast<unsigned int>(*current() &
                                                       get_mask<data_type, bits_per_pixel, MsbFirst>(remainder))
                             >> get_shift<num_intraword_positions, bits_per_pixel, MsbFirst>(remainder)));

        return (static_cast<unsigned int>(*current() &
                                          get_mask<data_type, bits_per_pixel, MsbFirst>(remainder))
                >> get_shift<num_intraword_positions, bits_per_pixel, MsbFirst>(remainder));
    }

    value_type get(difference_type const & d) const
    {
        const int remainder( x(d.x) % num_intraword_positions );

        // TODO(Q3): use traits to get unsigned type for data_type (if
        // not already)
        return (static_cast<unsigned int>(*current(d.x,d.y) &
                                          get_mask<data_type, bits_per_pixel, MsbFirst>(remainder))
                >> get_shift<num_intraword_positions, bits_per_pixel, MsbFirst>(remainder));
    }

    void set( value_type v ) const
    {
        const int remainder( x % num_intraword_positions );
        const int mask( get_mask<data_type, bits_per_pixel, MsbFirst>(remainder) );
        const value_type pixel_value(
            (v <<
             get_shift<num_intraword_positions, bits_per_pixel, MsbFirst>(remainder))
            & mask );
        pointer p = current();
        *p = (*p & ~mask) | pixel_value;
    }

    void set( value_type v, difference_type const & d ) const
    {
        const int remainder( (x + d.x) % num_intraword_positions );
        const int mask( get_mask<data_type, bits_per_pixel, MsbFirst>(remainder) );
        const value_type pixel_value(
            (v <<
             get_shift<num_intraword_positions, bits_per_pixel, MsbFirst>(remainder))
             & mask );
        pointer p = current(d.x,d.y);
        *p = (*p & ~mask) | pixel_value;
    }
};

} // namespace basebmp

#endif /* INCLUDED_BASEBMP_PACKEDPIXELITERATOR_HXX */