1 /* $OpenBSD: lib_ungetch.c,v 1.4 2023/10/17 09:52:09 nicm Exp $ */ 2 3 /**************************************************************************** 4 * Copyright 2020 Thomas E. Dickey * 5 * Copyright 1998-2011,2012 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 * and: Juergen Pfeifer 2009 * 37 ****************************************************************************/ 38 39 /* 40 ** lib_ungetch.c 41 ** 42 ** The routine ungetch(). 43 ** 44 */ 45 46 #include <curses.priv.h> 47 48 MODULE_ID("$Id: lib_ungetch.c,v 1.4 2023/10/17 09:52:09 nicm Exp $") 49 50 #include <fifo_defs.h> 51 52 #ifdef TRACE 53 NCURSES_EXPORT(void) 54 _nc_fifo_dump(SCREEN *sp) 55 { 56 int i; 57 T(("head = %d, tail = %d, peek = %d", head, tail, peek)); 58 for (i = 0; i < 10; i++) 59 T(("char %d = %s", i, _nc_tracechar(sp, sp->_fifo[i]))); 60 } 61 #endif /* TRACE */ 62 63 NCURSES_EXPORT(int) 64 safe_ungetch(SCREEN *sp, int ch) 65 { 66 int rc = ERR; 67 68 T((T_CALLED("ungetch(%p,%s)"), (void *) sp, _nc_tracechar(sp, ch))); 69 70 if (sp != 0 && tail >= 0) { 71 if (head < 0) { 72 head = 0; 73 t_inc(); 74 peek = tail; /* no raw keys */ 75 } else { 76 h_dec(); 77 } 78 79 sp->_fifo[head] = ch; 80 T(("ungetch %s ok", _nc_tracechar(sp, ch))); 81 #ifdef TRACE 82 if (USE_TRACEF(TRACE_IEVENT)) { 83 _nc_fifo_dump(sp); 84 _nc_unlock_global(tracef); 85 } 86 #endif 87 rc = OK; 88 } 89 returnCode(rc); 90 } 91 92 NCURSES_EXPORT(int) 93 ungetch(int ch) 94 { 95 return safe_ungetch(CURRENT_SCREEN, ch); 96 } 97