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/***************************************************************************
* COPYRIGHT NOTICE *
****************************************************************************
* ncurses is copyright (C) 1992-1995 *
* Zeyd M. Ben-Halim *
* zmbenhal@netcom.com *
* Eric S. Raymond *
* esr@snark.thyrsus.com *
* *
* Permission is hereby granted to reproduce and distribute ncurses *
* by any means and for any fee, whether alone or as part of a *
* larger distribution, in source or in binary form, PROVIDED *
* this notice is included with any such distribution, and is not *
* removed from any of its header files. Mention of ncurses in any *
* applications linked with it is highly appreciated. *
* *
* ncurses comes AS IS with no warranty, implied or expressed. *
* *
***************************************************************************/
/*
** lib_twait.c
**
** The routine _nc_timed_wait().
**
*/
#include "curses.priv.h"
#include <sys/types.h> /* some systems can't live without this */
#include <string.h>
#if HAVE_SYS_TIME_H && ! SYSTEM_LOOKS_LIKE_SCO
#include <sys/time.h>
#endif
#if HAVE_UNISTD_H
#include <unistd.h>
#endif
#if HAVE_SYS_SELECT_H
#include <sys/select.h>
#endif
/*
* We want to define GOOD_SELECT if the last argument of select(2) is
* modified to indicate time left. The code will deal gracefully with
* the other case, this is just an optimization to reduce the number
* of system calls per input event.
*
* In general, expect System-V-like UNIXes to have this behavior and BSD-like
* ones to not have it. Check your manual page. If it doesn't explicitly
* say the last argument is modified, assume it's not.
*
* (We'd really like configure to autodetect this, but writing a proper test
* turns out to be hard.)
*/
#if defined(linux)
#define GOOD_SELECT
#endif
#if !HAVE_USLEEP
int usleep(unsigned int usec)
{
struct timeval tval;
tval.tv_sec = usec / 1000000;
tval.tv_usec = usec % 1000000;
select(0, NULL, NULL, NULL, &tval);
}
#endif
int _nc_timed_wait(int fd, int wait, int *timeleft)
{
int result;
struct timeval ntimeout;
static fd_set set;
#if !defined(GOOD_SELECT) && HAVE_GETTIMEOFDAY
struct timeval starttime, returntime;
gettimeofday(&starttime, NULL);
#endif
FD_ZERO(&set);
FD_SET(fd, &set);
/* the units of wait are milliseconds */
ntimeout.tv_sec = wait / 1000;
ntimeout.tv_usec = (wait % 1000) * 1000;
T(("start twait: sec = %ld, usec = %ld", ntimeout.tv_sec, ntimeout.tv_usec));
result = select(fd+1, &set, NULL, NULL, &ntimeout);
#if !defined(GOOD_SELECT) && HAVE_GETTIMEOFDAY
gettimeofday(&returntime, NULL);
ntimeout.tv_sec -= (returntime.tv_sec - starttime.tv_sec);
ntimeout.tv_usec -= (returntime.tv_usec - starttime.tv_usec);
if (ntimeout.tv_usec < 0 && ntimeout.tv_sec > 0) {
ntimeout.tv_sec--;
ntimeout.tv_usec += 1000000;
}
if (ntimeout.tv_sec < 0)
ntimeout.tv_sec = ntimeout.tv_usec = 0;
#endif
/* return approximate time left on the ntimeout, in milliseconds */
if (timeleft)
*timeleft = (ntimeout.tv_sec * 1000) + (ntimeout.tv_usec / 1000);
T(("end twait: returned %d, sec = %ld, usec = %ld (%d msec)",
result, ntimeout.tv_sec, ntimeout.tv_usec,
timeleft ? *timeleft : -1));
return(result);
}
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