/* ***** BEGIN LICENSE BLOCK *****
 * Source last modified: $Id: region.c,v 1.3.12.1 2004/07/09 01:59:28 hubbe Exp $
 * 
 * Portions Copyright (c) 1995-2004 RealNetworks, Inc. All Rights Reserved.
 * 
 * The contents of this file, and the files included with this file,
 * are subject to the current version of the RealNetworks Public
 * Source License (the "RPSL") available at
 * http://www.helixcommunity.org/content/rpsl unless you have licensed
 * the file under the current version of the RealNetworks Community
 * Source License (the "RCSL") available at
 * http://www.helixcommunity.org/content/rcsl, in which case the RCSL
 * will apply. You may also obtain the license terms directly from
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 * to this file, the RCSL.  Please see the applicable RPSL or RCSL for
 * the rights, obligations and limitations governing use of the
 * contents of the file.
 * 
 * Alternatively, the contents of this file may be used under the
 * terms of the GNU General Public License Version 2 or later (the
 * "GPL") in which case the provisions of the GPL are applicable
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 * 
 * This file is part of the Helix DNA Technology. RealNetworks is the
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 * ***** END LICENSE BLOCK ***** */

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

Copyright (c) 1987, 1988  X Consortium

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
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The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.
 
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CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

Except as contained in this notice, the name of the X Consortium shall not be
used in advertising or otherwise to promote the sale, use or other dealings
in this Software without prior written authorization from the X Consortium.


Copyright 1987, 1988 by Digital Equipment Corporation, Maynard, Massachusetts.

                        All Rights Reserved

Permission to use, copy, modify, and distribute this software and its 
documentation for any purpose and without fee is hereby granted, 
provided that the above copyright notice appear in all copies and that
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supporting documentation, and that the name of Digital not be
used in advertising or publicity pertaining to distribution of the
software without specific, written prior permission.  

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WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
SOFTWARE.

************************************************************************/
/*
 * The functions in this file implement the _Region abstraction, similar to one
 * used in the X11 sample server. A _Region is simply an area, as the name
 * implies, and is implemented as a "y-x-banded" array of rectangles. To
 * explain: Each _Region is made up of a certain number of rectangles sorted
 * by y coordinate first, and then by x coordinate.
 *
 * Furthermore, the rectangles are banded such that every rectangle with a
 * given upper-left y coordinate (y1) will have the same lower-right y
 * coordinate (y2) and vice versa. If a rectangle has scanlines in a band, it
 * will span the entire vertical distance of the band. This means that some
 * areas that could be merged into a taller rectangle will be represented as
 * several shorter rectangles to account for shorter rectangles to its left
 * or right but within its "vertical scope".
 *
 * An added constraint on the rectangles is that they must cover as much
 * horizontal area as possible. E.g. no two rectangles in a band are allowed
 * to touch.
 *
 * Whenever possible, bands will be merged together to cover a greater vertical
 * distance (and thus reduce the number of rectangles). Two bands can be merged
 * only if the bottom of one touches the top of the other and they have
 * rectangles in the same places (of the same width, of course). This maintains
 * the y-x-banding that's so nice to have...
 */
/* $XFree86: xc/lib/X11/_Region.c,v 1.1.1.2.2.2 1998/10/04 15:22:50 hohndel Exp $ */

#include "region.h"
#include "hlxclib/stdlib.h"
#include "hlxclib/memory.h"

#ifdef _DEBUG
#include <hlxclib/stdio.h> /* for _DumpRegion() */
#ifdef _WINDOWS
#include "windows.h"
#endif
#endif

#include <hlxclib/string.h>

typedef void (*voidProcp)();

                        
typedef int (*overlapFunc)( register _HXRegion  pReg,
                            register HXBoxPtr   r1,
                            HXBoxPtr            r1End,
                            register HXBoxPtr   r2,
                            HXBoxPtr            r2End,
                            register short      y1,
                            register short      y2
                            );

typedef int (*nonOverlapFunc)( register _HXRegion  pReg,
                               register HXBoxPtr   r,
                               HXBoxPtr            rEnd,
                               register short      y1,
                               register short      y2
                               );

static void miRegionOp( _HXRegion      newReg,                 
                        _HXRegion      reg1,                   
                        _HXRegion      reg2,                   
                        overlapFunc    overlap,
                        nonOverlapFunc nonoverlap,
                        nonOverlapFunc nonoverlap2  
                        );


/* Create a new empty region    */ 
_HXRegion HXCreateRegion()
{
    _HXRegion temp;

    if (! (temp = ( _HXRegion )malloc( (unsigned) sizeof( HXREGION ))))
        return (_HXRegion) NULL;
    if (! (temp->rects = ( HXBOX * )malloc( (unsigned) sizeof( HXBOX )))) {
        free((char *) temp);
        return (_HXRegion) NULL;
    }
    temp->numRects = 0;
    temp->extents.x1 = 0;
    temp->extents.y1 = 0;
    temp->extents.x2 = 0;
    temp->extents.y2 = 0;
    temp->size = 1;
    return( temp );
}

int HXClipRBox( _HXRegion r, HXRECTANGLE* rect)
{
    rect->x = r->extents.x1;
    rect->y = r->extents.y1;
    rect->width = r->extents.x2 - r->extents.x1;
    rect->height = r->extents.y2 - r->extents.y1;
    return 1;
}

_HXRegion HXCreateRectRegion(int left, int top, int width, int height)
{
    _HXRegion pRegion = HXCreateRegion();
    
    /*  
        too scared to put this code in. Will have to check to see if everything 
        works with it later.
    
    pRegion->numRects++;
    temp->rects.x1 = pRegion->extents.x1 = left;
    temp->rects.y1 = pRegion->extents.y1 = top;
    temp->rects.x2 = pRegion->extents.x2 = right;
    temp->rects.y2 = pRegion->extents.y2 = bottom;
    */
    
    HXRECTANGLE tempRECT;
    tempRECT.x      =   left;
    tempRECT.y      =   top;
    tempRECT.width  =   width;
    tempRECT.height =   height;

    HXUnionRectWithRegion(&tempRECT, pRegion, pRegion);
    return pRegion;
}


//=======================================================================
//=======================================================================
//               New methods to act on regions
//=======================================================================
//=======================================================================



int HXCombineRgn( _HXRegion destRgn,
                   _HXRegion srcRgn1,
                   _HXRegion srcRgn2,
                   HXRegionArithmetic rgnOperation)
{
//   HX_ASSERT( destRgn && srcRgn1 && srcRgn2);
   switch (rgnOperation)
   {
      case HX_RGN_DIFF:
         HXSubtractRegion( srcRgn1, srcRgn2, destRgn );
         break;
        
      case HX_RGN_AND:
         HXIntersectRegion( srcRgn1, srcRgn2, destRgn );
         break;
        
      case HX_RGN_OR:
         HXUnionRegion(srcRgn1, srcRgn2, destRgn );
         break;
        
      case HX_RGN_XOR:
         HXXorRegion( srcRgn1, srcRgn2, destRgn );
         break;
        
      default:
//         HX_ASSERT(!"Egads! Unknown HXCombineRgn Operation!");
         break;
   }
   return 0;
}

//=======================================================================
//=======================================================================
//               END: New methods to act on regions
//=======================================================================
//=======================================================================


int HXUnionRectWithRegion(HXRECTANGLE* rect, _HXRegion source, _HXRegion dest)
{
    HXREGION region;

    if (!rect->width || !rect->height)
        return 0;
    region.rects = &region.extents;
    region.numRects = 1;
    region.extents.x1 = rect->x;
    region.extents.y1 = rect->y;
    region.extents.x2 = rect->x + rect->width;
    region.extents.y2 = rect->y + rect->height;
    region.size = 1;

    return HXUnionRegion(&region, source, dest);
}

/*-
 *-----------------------------------------------------------------------
 * miSetExtents --
 *      Reset the extents of a region to what they should be. Called by
 *      miSubtract and miIntersect b/c they can't figure it out along the
 *      way or do so easily, as miUnion can.
 *
 * Results:
 *      None.
 *
 * Side Effects:
 *      The region's 'extents' structure is overwritten.
 *
 *-----------------------------------------------------------------------
 */
static void
miSetExtents (_HXRegion pReg)
{
    register HXBoxPtr   pHXBox,
                        pHXBoxEnd,
                        pExtents;

    if (pReg->numRects == 0)
    {
        pReg->extents.x1 = 0;
        pReg->extents.y1 = 0;
        pReg->extents.x2 = 0;
        pReg->extents.y2 = 0;
        return;
    }

    pExtents = &pReg->extents;
    pHXBox = pReg->rects;
    pHXBoxEnd = &pHXBox[pReg->numRects - 1];

    /*
     * Since pHXBox is the first rectangle in the region, it must have the
     * smallest y1 and since pHXBoxEnd is the last rectangle in the region,
     * it must have the largest y2, because of banding. Initialize x1 and
     * x2 from  pHXBox and pHXBoxEnd, resp., as good things to initialize them
     * to...
     */
    pExtents->x1 = pHXBox->x1;
    pExtents->y1 = pHXBox->y1;
    pExtents->x2 = pHXBoxEnd->x2;
    pExtents->y2 = pHXBoxEnd->y2;

    /* assert(pExtents->y1 < pExtents->y2); */
    while (pHXBox <= pHXBoxEnd)
    {
        if (pHXBox->x1 < pExtents->x1)
        {
            pExtents->x1 = pHXBox->x1;
        }
        if (pHXBox->x2 > pExtents->x2)
        {
            pExtents->x2 = pHXBox->x2;
        }
        pHXBox++;
    }
    /* assert(pExtents->x1 < pExtents->x2); */
}

int HXZeroOutRegion(_HXRegion r)
{
    if (!r)
    {
        return 0;
    }
    
    if( r->rects )
        free( (char *) r->rects );
    
    if( !(r->rects = ( HXBOX * )malloc( (unsigned) sizeof( HXBOX ))) )
    {
        return 0;
    }
    
    r->numRects = 0;
    r->extents.x1 = 0;
    r->extents.y1 = 0;
    r->extents.x2 = 0;
    r->extents.y2 = 0;
    r->size = 1;
    
    return 1;
}

int HXDestroyRegion(_HXRegion r)
{
    if (!r)
    {
        return 0;
    }
    free( (char *) r->rects );
    free( (char *) r );
    return 1;
}


/* TranslateRegion(pRegion, x, y)
   translates in place
   added by raymond
*/

int HXOffsetRegion(_HXRegion pRegion, int x, int y)
{
    register int nHXBox;
    register HXBOX *pHXBox;

    pHXBox = pRegion->rects;
    nHXBox = pRegion->numRects;

    while(nHXBox--)
    {
        pHXBox->x1 += x;
        pHXBox->x2 += x;
        pHXBox->y1 += y;
        pHXBox->y2 += y;
        pHXBox++;
    }
    pRegion->extents.x1 += x;
    pRegion->extents.x2 += x;
    pRegion->extents.y1 += y;
    pRegion->extents.y2 += y;
    return 1;
}

/* 
   Utility procedure Compress:
   Replace r by the region r', where 
     p in r' iff (Quantifer m <= dx) (p + m in r), and
     Quantifier is Exists if grow is TRUE, For all if grow is FALSE, and
     (x,y) + m = (x+m,y) if xdir is TRUE; (x,y+m) if xdir is FALSE.

   Thus, if xdir is TRUE and grow is FALSE, r is replaced by the region
   of all points p such that p and the next dx points on the same
   horizontal scan line are all in r.  We do this using by noting
   that p is the head of a run of length 2^i + k iff p is the head
   of a run of length 2^i and p+2^i is the head of a run of length
   k. Thus, the loop invariant: s contains the region corresponding
   to the runs of length shift.  r contains the region corresponding
   to the runs of length 1 + dxo & (shift-1), where dxo is the original
   value of dx.  dx = dxo & ~(shift-1).  As parameters, s and t are
   scratch regions, so that we don't have to allocate them on every
   call.
*/

#define ZOpRegion(a,b,c) if (grow) HXUnionRegion(a,b,c); \
                         else HXIntersectRegion(a,b,c)
#define ZShiftRegion(a,b) if (xdir) HXOffsetRegion(a,b,0); \
                          else HXOffsetRegion(a,0,b)
#define ZCopyRegion(a,b) HXUnionRegion(a,a,b)

static void
Compress(_HXRegion r, _HXRegion s, _HXRegion t, unsigned dx, int xdir, int grow)
{
    register unsigned shift = 1;

    ZCopyRegion(r, s);
    while (dx) {
        if (dx & shift) {
            ZShiftRegion(r, -(int)shift);
            ZOpRegion(r, s, r);
            dx -= shift;
            if (!dx) break;
        }
        ZCopyRegion(s, t);
        ZShiftRegion(s, -(int)shift);
        ZOpRegion(s, t, s);
        shift <<= 1;
    }