1 /****************************************************************************
2  * Copyright 2020 Thomas E. Dickey                                          *
3  * Copyright 2002-2011,2016 Free Software Foundation, Inc.                  *
4  *                                                                          *
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29 
30 /****************************************************************************
31  *  Author: Thomas E. Dickey 2002-on                                        *
32  ****************************************************************************/
33 
34 /*
35 **	lib_get_wch.c
36 **
37 **	The routine get_wch().
38 **
39 */
40 
41 #include <curses.priv.h>
42 #include <ctype.h>
43 
44 MODULE_ID("$Id: lib_get_wch.c,v 1.25 2020/02/02 23:34:34 tom Exp $")
45 
46 NCURSES_EXPORT(int)
47 wget_wch(WINDOW *win, wint_t *result)
48 {
49     SCREEN *sp;
50     int code;
51     int value = 0;
52     wchar_t wch;
53 #ifndef state_unused
54     mbstate_t state;
55 #endif
56 
57     T((T_CALLED("wget_wch(%p)"), (void *) win));
58 
59     /*
60      * We can get a stream of single-byte characters and KEY_xxx codes from
61      * _nc_wgetch(), while we want to return a wide character or KEY_xxx code.
62      */
63     _nc_lock_global(curses);
64     sp = _nc_screen_of(win);
65 
66     if (sp != 0) {
67 	size_t count = 0;
68 
69 	for (;;) {
70 	    char buffer[(MB_LEN_MAX * 9) + 1];	/* allow some redundant shifts */
71 
72 	    T(("reading %d of %d", (int) count + 1, (int) sizeof(buffer)));
73 	    code = _nc_wgetch(win, &value, TRUE EVENTLIST_2nd((_nc_eventlist
74 							       *) 0));
75 	    if (code == ERR) {
76 		break;
77 	    } else if (code == KEY_CODE_YES) {
78 		/*
79 		 * If we were processing an incomplete multibyte character,
80 		 * return an error since we have a KEY_xxx code which
81 		 * interrupts it.  For some cases, we could improve this by
82 		 * writing a new version of lib_getch.c(!), but it is not clear
83 		 * whether the improvement would be worth the effort.
84 		 */
85 		if (count != 0) {
86 		    safe_ungetch(SP_PARM, value);
87 		    code = ERR;
88 		}
89 		break;
90 	    } else if (count + 1 >= sizeof(buffer)) {
91 		safe_ungetch(SP_PARM, value);
92 		code = ERR;
93 		break;
94 	    } else {
95 		int status;
96 
97 		buffer[count++] = (char) UChar(value);
98 		reset_mbytes(state);
99 		status = count_mbytes(buffer, count, state);
100 		if (status >= 0) {
101 		    reset_mbytes(state);
102 		    if (check_mbytes(wch, buffer, count, state) != status) {
103 			code = ERR;	/* the two calls should match */
104 			safe_ungetch(SP_PARM, value);
105 		    }
106 		    value = wch;
107 		    break;
108 		}
109 	    }
110 	}
111     } else {
112 	code = ERR;
113     }
114 
115     if (result != 0)
116 	*result = (wint_t) value;
117 
118     _nc_unlock_global(curses);
119     T(("result %#o", value));
120     returnCode(code);
121 }
122