xref: /openbsd/lib/libcurses/base/lib_erase.c (revision a6445c1d)
1 /* $OpenBSD: lib_erase.c,v 1.3 2010/01/12 23:22:05 nicm Exp $ */
2 
3 /****************************************************************************
4  * Copyright (c) 1998,2000,2001 Free Software Foundation, Inc.              *
5  *                                                                          *
6  * Permission is hereby granted, free of charge, to any person obtaining a  *
7  * copy of this software and associated documentation files (the            *
8  * "Software"), to deal in the Software without restriction, including      *
9  * without limitation the rights to use, copy, modify, merge, publish,      *
10  * distribute, distribute with modifications, sublicense, and/or sell       *
11  * copies of the Software, and to permit persons to whom the Software is    *
12  * furnished to do so, subject to the following conditions:                 *
13  *                                                                          *
14  * The above copyright notice and this permission notice shall be included  *
15  * in all copies or substantial portions of the Software.                   *
16  *                                                                          *
17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS  *
18  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF               *
19  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.   *
20  * IN NO EVENT SHALL THE ABOVE COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,   *
21  * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR    *
22  * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR    *
23  * THE USE OR OTHER DEALINGS IN THE SOFTWARE.                               *
24  *                                                                          *
25  * Except as contained in this notice, the name(s) of the above copyright   *
26  * holders shall not be used in advertising or otherwise to promote the     *
27  * sale, use or other dealings in this Software without prior written       *
28  * authorization.                                                           *
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30 
31 /****************************************************************************
32  *  Author: Zeyd M. Ben-Halim <zmbenhal@netcom.com> 1992,1995               *
33  *     and: Eric S. Raymond <esr@snark.thyrsus.com>                         *
34  *     and: Thomas E. Dickey                        1996-on                 *
35  ****************************************************************************/
36 
37 /*
38 **	lib_erase.c
39 **
40 **	The routine werase().
41 **
42 */
43 
44 #include <curses.priv.h>
45 
46 MODULE_ID("$Id: lib_erase.c,v 1.3 2010/01/12 23:22:05 nicm Exp $")
47 
48 NCURSES_EXPORT(int)
49 werase(WINDOW *win)
50 {
51     int code = ERR;
52     int y;
53     NCURSES_CH_T blank;
54     NCURSES_CH_T *sp, *end, *start;
55 
56     T((T_CALLED("werase(%p)"), win));
57 
58     if (win) {
59 	blank = win->_nc_bkgd;
60 	for (y = 0; y <= win->_maxy; y++) {
61 	    start = win->_line[y].text;
62 	    end = &start[win->_maxx];
63 
64 	    /*
65 	     * If this is a derived window, we have to handle the case where
66 	     * a multicolumn character extends into the window that we are
67 	     * erasing.
68 	     */
69 	    if_WIDEC({
70 		if (isWidecExt(start[0])) {
71 		    int x = (win->_parent != 0) ? (win->_begx) : 0;
72 		    while (x-- > 0) {
73 			if (isWidecBase(start[-1])) {
74 			    --start;
75 			    break;
76 			}
77 			--start;
78 		    }
79 		}
80 	    });
81 
82 	    for (sp = start; sp <= end; sp++)
83 		*sp = blank;
84 
85 	    win->_line[y].firstchar = 0;
86 	    win->_line[y].lastchar = win->_maxx;
87 	}
88 	win->_curx = win->_cury = 0;
89 	win->_flags &= ~_WRAPPED;
90 	_nc_synchook(win);
91 	code = OK;
92     }
93     returnCode(code);
94 }
95