/****************************************************************************
 * Copyright (c) 1998-2002,2006 Free Software Foundation, Inc.              *
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 * 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, distribute with modifications, sublicense, and/or sell       *
 * copies of the Software, and to permit persons to whom the Software is    *
 * furnished to do so, subject to the following conditions:                 *
 *                                                                          *
 * The above copyright notice and this permission notice shall be included  *
 * in all copies or substantial portions of the Software.                   *
 *                                                                          *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS  *
 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF               *
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.   *
 * IN NO EVENT SHALL THE ABOVE COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,   *
 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR    *
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 ****************************************************************************/

/****************************************************************************
 *  Author: Zeyd M. Ben-Halim <zmbenhal@netcom.com> 1992,1995               *
 *     and: Eric S. Raymond <esr@snark.thyrsus.com>                         *
 ****************************************************************************/

/*
**	lib_overlay.c
**
**	The routines overlay(), copywin(), and overwrite().
**
*/

#include <curses.priv.h>

MODULE_ID("$Id: lib_overlay.c,v 1.22 2006/10/14 20:43:31 tom Exp $")

static int
overlap(const WINDOW *const s, WINDOW *const d, int const flag)
{
    int sx1, sy1, sx2, sy2;
    int dx1, dy1, dx2, dy2;
    int sminrow, smincol;
    int dminrow, dmincol;
    int dmaxrow, dmaxcol;

    T((T_CALLED("overlap(%p,%p,%d)"), s, d, flag));

    if (s == 0 || d == 0) {
	returnCode(ERR);
    } else {
	T(("src : begy %ld, begx %ld, maxy %ld, maxx %ld",
	   (long) s->_begy,
	   (long) s->_begx,
	   (long) s->_maxy,
	   (long) s->_maxx));
	T(("dst : begy %ld, begx %ld, maxy %ld, maxx %ld",
	   (long) d->_begy,
	   (long) d->_begx,
	   (long) d->_maxy,
	   (long) d->_maxx));

	sx1 = s->_begx;
	sy1 = s->_begy;
	sx2 = sx1 + s->_maxx;
	sy2 = sy1 + s->_maxy;

	dx1 = d->_begx;
	dy1 = d->_begy;
	dx2 = dx1 + d->_maxx;
	dy2 = dy1 + d->_maxy;

	if (dx2 < sx1 || dx1 > sx2 || dy2 < sy1 || dy1 > sy2) {
	    returnCode(ERR);	/* No intersection */
	} else {
	    sminrow = max(sy1, dy1) - sy1;
	    smincol = max(sx1, dx1) - sx1;
	    dminrow = max(sy1, dy1) - dy1;
	    dmincol = max(sx1, dx1) - dx1;
	    dmaxrow = min(sy2, dy2) - dy1;
	    dmaxcol = min(sx2, dx2) - dx1;

	    returnCode(copywin(s, d,
			       sminrow, smincol,
			       dminrow, dmincol,
			       dmaxrow, dmaxcol,
			       flag));
	}
    }
}

/*
**
**	overlay(win1, win2)
**
**
**	overlay() writes the overlapping area of win1 behind win2
**	on win2 non-destructively.
**
**/

NCURSES_EXPORT(int)
overlay(const WINDOW *win1, WINDOW *win2)
{
    T((T_CALLED("overlay(%p,%p)"), win1, win2));
    returnCode(overlap(win1, win2, TRUE));
}

/*
**
**	overwrite(win1, win2)
**
**
**	overwrite() writes the overlapping area of win1 behind win2
**	on win2 destructively.
**
**/

NCURSES_EXPORT(int)
overwrite(const WINDOW *win1, WINDOW *win2)
{
    T((T_CALLED("overwrite(%p,%p)"), win1, win2));
    returnCode(overlap(win1, win2, FALSE));
}

NCURSES_EXPORT(int)
copywin(const WINDOW *src, WINDOW *dst,
	int sminrow, int smincol,
	int dminrow, int dmincol,
	int dmaxrow, int dmaxcol,
	int over)
{
    int sx, sy, dx, dy;
    bool touched;
    attr_t bk = AttrOf(dst->_nc_bkgd);
    attr_t mask = ~(attr_t) ((bk & A_COLOR) ? A_COLOR : 0);

    T((T_CALLED("copywin(%p, %p, %d, %d, %d, %d, %d, %d, %d)"),
       src, dst, sminrow, smincol, dminrow, dmincol, dmaxrow, dmaxcol, over));

    if (!src || !dst)
	returnCode(ERR);

    /* make sure rectangle exists in source */
    if ((sminrow + dmaxrow - dminrow) > (src->_maxy + 1) ||
	(smincol + dmaxcol - dmincol) > (src->_maxx + 1)) {
	returnCode(ERR);
    }

    T(("rectangle exists in source"));

    /* make sure rectangle fits in destination */
    if (dmaxrow > dst->_maxy || dmaxcol > dst->_maxx) {
	returnCode(ERR);
    }

    T(("rectangle fits in destination"));

    for (dy = dminrow, sy = sminrow; dy <= dmaxrow; sy++, dy++) {
	touched = FALSE;
	for (dx = dmincol, sx = smincol; dx <= dmaxcol; sx++, dx++) {
	    if (over) {
		if ((CharOf(src->_line[sy].text[sx]) != L(' ')) &&
		    (!CharEq(dst->_line[dy].text[dx], src->_line[sy].text[sx]))) {
		    dst->_line[dy].text[dx] = src->_line[sy].text[sx];
		    SetAttr(dst->_line[dy].text[dx],
			    (AttrOf(src->_line[sy].text[sx]) & mask) | bk);
		    touched = TRUE;
		}
	    } else {
		if (!CharEq(dst->_line[dy].text[dx], src->_line[sy].text[sx])) {
		    dst->_line[dy].text[dx] = src->_line[sy].text[sx];
		    touched = TRUE;
		}
	    }
	}
	if (touched) {
	    touchline(dst, dminrow, (dmaxrow - dminrow + 1));
	}
    }
    T(("finished copywin"));
    returnCode(OK);
}