xref: /openbsd/lib/libcurses/base/lib_erase.c (revision 3bef86f7)
1 /* $OpenBSD: lib_erase.c,v 1.4 2023/10/17 09:52:08 nicm Exp $ */
2 
3 /****************************************************************************
4  * Copyright 2020,2022 Thomas E. Dickey                                     *
5  * Copyright 1998-2009,2016 Free Software Foundation, Inc.                  *
6  *                                                                          *
7  * Permission is hereby granted, free of charge, to any person obtaining a  *
8  * copy of this software and associated documentation files (the            *
9  * "Software"), to deal in the Software without restriction, including      *
10  * without limitation the rights to use, copy, modify, merge, publish,      *
11  * distribute, distribute with modifications, sublicense, and/or sell       *
12  * copies of the Software, and to permit persons to whom the Software is    *
13  * furnished to do so, subject to the following conditions:                 *
14  *                                                                          *
15  * The above copyright notice and this permission notice shall be included  *
16  * in all copies or substantial portions of the Software.                   *
17  *                                                                          *
18  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS  *
19  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF               *
20  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.   *
21  * IN NO EVENT SHALL THE ABOVE COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,   *
22  * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR    *
23  * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR    *
24  * THE USE OR OTHER DEALINGS IN THE SOFTWARE.                               *
25  *                                                                          *
26  * Except as contained in this notice, the name(s) of the above copyright   *
27  * holders shall not be used in advertising or otherwise to promote the     *
28  * sale, use or other dealings in this Software without prior written       *
29  * authorization.                                                           *
30  ****************************************************************************/
31 
32 /****************************************************************************
33  *  Author: Zeyd M. Ben-Halim <zmbenhal@netcom.com> 1992,1995               *
34  *     and: Eric S. Raymond <esr@snark.thyrsus.com>                         *
35  *     and: Thomas E. Dickey                        1996-on                 *
36  ****************************************************************************/
37 
38 /*
39 **	lib_erase.c
40 **
41 **	The routine werase().
42 **
43 */
44 
45 #include <curses.priv.h>
46 
47 MODULE_ID("$Id: lib_erase.c,v 1.4 2023/10/17 09:52:08 nicm Exp $")
48 
49 NCURSES_EXPORT(int)
50 werase(WINDOW *win)
51 {
52     int code = ERR;
53     NCURSES_CH_T *start;
54 
55     T((T_CALLED("werase(%p)"), (void *) win));
56 
57     if (win) {
58 	NCURSES_CH_T blank;
59 	NCURSES_CH_T *sp;
60 	int y;
61 
62 	blank = win->_nc_bkgd;
63 	for (y = 0; y <= win->_maxy; y++) {
64 	    NCURSES_CH_T *end;
65 
66 	    start = win->_line[y].text;
67 	    end = &start[win->_maxx];
68 
69 	    /*
70 	     * If this is a derived window, we have to handle the case where
71 	     * a multicolumn character extends into the window that we are
72 	     * erasing.
73 	     */
74 	    if_WIDEC({
75 		if (isWidecExt(start[0])) {
76 		    int x = (win->_parent != 0) ? (win->_begx) : 0;
77 		    while (x-- > 0) {
78 			if (isWidecBase(start[-1])) {
79 			    --start;
80 			    break;
81 			}
82 			--start;
83 		    }
84 		}
85 	    });
86 
87 	    for (sp = start; sp <= end; sp++)
88 		*sp = blank;
89 
90 	    win->_line[y].firstchar = 0;
91 	    win->_line[y].lastchar = win->_maxx;
92 	}
93 	win->_curx = win->_cury = 0;
94 	win->_flags &= ~_WRAPPED;
95 	_nc_synchook(win);
96 	code = OK;
97     }
98     returnCode(code);
99 }
100