release/src/router/libncurses/ncurses/base/lib_ungetch.c

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   2  * Copyright (c) 1998-2008,2009 Free Software Foundation, Inc.              *
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  28
  29 /****************************************************************************
  30  *  Author: Zeyd M. Ben-Halim <zmbenhal@netcom.com> 1992,1995               *
  31  *     and: Eric S. Raymond <esr@snark.thyrsus.com>                         *
  32  *     and: Thomas E. Dickey                        1996-on                 *
  33  *     and: Juergen Pfeifer                         2009                    *
  34  ****************************************************************************/
  35
  36 /*
  37 **      lib_ungetch.c
  38 **
  39 **      The routine ungetch().
  40 **
  41 */
  42
  43 #include <curses.priv.h>
  44
  45 MODULE_ID("$Id: lib_ungetch.c,v 1.14 2009/10/24 22:12:21 tom Exp $")
  46
  47 #include <fifo_defs.h>
  48
  49 #ifdef TRACE
  50 NCURSES_EXPORT(void)
  51 _nc_fifo_dump(SCREEN *sp)
  52 {
  53     int i;
  54     T(("head = %d, tail = %d, peek = %d", head, tail, peek));
  55     for (i = 0; i < 10; i++)
  56         T(("char %d = %s", i, _nc_tracechar(sp, sp->_fifo[i])));
  57 }
  58 #endif /* TRACE */
  59
  60 NCURSES_EXPORT(int)
  61 safe_ungetch(SCREEN *sp, int ch)
  62 {
  63     int rc = ERR;
  64
  65     T((T_CALLED("ungetch(%p,%s)"), (void *) sp, _nc_tracechar(sp, ch)));
  66
  67     if (tail != -1) {
  68         if (head == -1) {
  69             head = 0;
  70             t_inc();
  71             peek = tail;        /* no raw keys */
  72         } else
  73             h_dec();
  74
  75         sp->_fifo[head] = ch;
  76         T(("ungetch %s ok", _nc_tracechar(sp, ch)));
  77 #ifdef TRACE
  78         if (USE_TRACEF(TRACE_IEVENT)) {
  79             _nc_fifo_dump(sp);
  80             _nc_unlock_global(tracef);
  81         }
  82 #endif
  83         rc = OK;
  84     }
  85     returnCode(rc);
  86 }
  87
  88 NCURSES_EXPORT(int)
  89 ungetch(int ch)
  90 {
  91     return safe_ungetch(CURRENT_SCREEN, ch);
  92 }