1 /****************************************************************************
2  * Copyright 2020 Thomas E. Dickey                                          *
3  * Copyright 1998-2009,2016 Free Software Foundation, Inc.                  *
4  *                                                                          *
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6  * copy of this software and associated documentation files (the            *
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11  * furnished to do so, subject to the following conditions:                 *
12  *                                                                          *
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15  *                                                                          *
16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS  *
17  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF               *
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22  * THE USE OR OTHER DEALINGS IN THE SOFTWARE.                               *
23  *                                                                          *
24  * Except as contained in this notice, the name(s) of the above copyright   *
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29 
30 /****************************************************************************
31  *  Author: Zeyd M. Ben-Halim <zmbenhal@netcom.com> 1992,1995               *
32  *     and: Eric S. Raymond <esr@snark.thyrsus.com>                         *
33  *     and: Thomas E. Dickey                        1996-on                 *
34  ****************************************************************************/
35 
36 /*
37 **	lib_erase.c
38 **
39 **	The routine werase().
40 **
41 */
42 
43 #include <curses.priv.h>
44 
45 MODULE_ID("$Id: lib_erase.c,v 1.19 2020/02/02 23:34:34 tom Exp $")
46 
47 NCURSES_EXPORT(int)
48 werase(WINDOW *win)
49 {
50     int code = ERR;
51     NCURSES_CH_T blank;
52     NCURSES_CH_T *start;
53 
54     T((T_CALLED("werase(%p)"), (void *) win));
55 
56     if (win) {
57 	NCURSES_CH_T *sp;
58 	int y;
59 
60 	blank = win->_nc_bkgd;
61 	for (y = 0; y <= win->_maxy; y++) {
62 	    NCURSES_CH_T *end;
63 
64 	    start = win->_line[y].text;
65 	    end = &start[win->_maxx];
66 
67 	    /*
68 	     * If this is a derived window, we have to handle the case where
69 	     * a multicolumn character extends into the window that we are
70 	     * erasing.
71 	     */
72 	    if_WIDEC({
73 		if (isWidecExt(start[0])) {
74 		    int x = (win->_parent != 0) ? (win->_begx) : 0;
75 		    while (x-- > 0) {
76 			if (isWidecBase(start[-1])) {
77 			    --start;
78 			    break;
79 			}
80 			--start;
81 		    }
82 		}
83 	    });
84 
85 	    for (sp = start; sp <= end; sp++)
86 		*sp = blank;
87 
88 	    win->_line[y].firstchar = 0;
89 	    win->_line[y].lastchar = win->_maxx;
90 	}
91 	win->_curx = win->_cury = 0;
92 	win->_flags &= ~_WRAPPED;
93 	_nc_synchook(win);
94 	code = OK;
95     }
96     returnCode(code);
97 }
98