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28 
29 /****************************************************************************
30  *  Author: Thomas E. Dickey 2002-on                                        *
31  ****************************************************************************/
32 
33 /*
34 **	lib_get_wch.c
35 **
36 **	The routine get_wch().
37 **
38 */
39 
40 #include <curses.priv.h>
41 #include <ctype.h>
42 
43 MODULE_ID("$Id: lib_get_wch.c,v 1.17 2008/08/16 19:22:55 tom Exp $")
44 
45 #if HAVE_MBTOWC && HAVE_MBLEN
46 #define reset_mbytes(state) mblen(NULL, 0), mbtowc(NULL, NULL, 0)
47 #define count_mbytes(buffer,length,state) mblen(buffer,length)
48 #define check_mbytes(wch,buffer,length,state) \
49 	(int) mbtowc(&wch, buffer, length)
50 #define state_unused
51 #elif HAVE_MBRTOWC && HAVE_MBRLEN
52 #define reset_mbytes(state) init_mb(state)
53 #define count_mbytes(buffer,length,state) mbrlen(buffer,length,&state)
54 #define check_mbytes(wch,buffer,length,state) \
55 	(int) mbrtowc(&wch, buffer, length, &state)
56 #else
57 make an error
58 #endif
59 
60 NCURSES_EXPORT(int)
61 wget_wch(WINDOW *win, wint_t *result)
62 {
63     SCREEN *sp;
64     int code;
65     char buffer[(MB_LEN_MAX * 9) + 1];	/* allow some redundant shifts */
66     int status;
67     size_t count = 0;
68     unsigned long value;
69     wchar_t wch;
70 #ifndef state_unused
71     mbstate_t state;
72 #endif
73 
74     T((T_CALLED("wget_wch(%p)"), win));
75 
76     /*
77      * We can get a stream of single-byte characters and KEY_xxx codes from
78      * _nc_wgetch(), while we want to return a wide character or KEY_xxx code.
79      */
80     _nc_lock_global(curses);
81     sp = _nc_screen_of(win);
82     if (sp != 0) {
83 	for (;;) {
84 	    T(("reading %d of %d", (int) count + 1, (int) sizeof(buffer)));
85 	    code = _nc_wgetch(win, &value, TRUE EVENTLIST_2nd((_nc_eventlist
86 							       *) 0));
87 	    if (code == ERR) {
88 		break;
89 	    } else if (code == KEY_CODE_YES) {
90 		/*
91 		 * If we were processing an incomplete multibyte character,
92 		 * return an error since we have a KEY_xxx code which
93 		 * interrupts it.  For some cases, we could improve this by
94 		 * writing a new version of lib_getch.c(!), but it is not clear
95 		 * whether the improvement would be worth the effort.
96 		 */
97 		if (count != 0) {
98 		    _nc_ungetch(sp, (int) value);
99 		    code = ERR;
100 		}
101 		break;
102 	    } else if (count + 1 >= sizeof(buffer)) {
103 		_nc_ungetch(sp, (int) value);
104 		code = ERR;
105 		break;
106 	    } else {
107 		buffer[count++] = (char) UChar(value);
108 		reset_mbytes(state);
109 		status = count_mbytes(buffer, count, state);
110 		if (status >= 0) {
111 		    reset_mbytes(state);
112 		    if (check_mbytes(wch, buffer, count, state) != status) {
113 			code = ERR;	/* the two calls should match */
114 			_nc_ungetch(sp, (int) value);
115 		    }
116 		    value = wch;
117 		    break;
118 		}
119 	    }
120 	}
121     } else {
122 	code = ERR;
123     }
124     *result = value;
125     _nc_unlock_global(curses);
126     T(("result %#lo", value));
127     returnCode(code);
128 }
129