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freebsd/games/grdc/grdc.c
Xin LI eb1930d3f2 Improve time precision for grdc(6):
Traditionally, grdc would obtain time through time(3) which in turn gets
only the second part of clock (CLOCK_SECOND), and sleep for 1 second after
each screen refresh.

This approach would have two problems.  First, we are not guaranteed to
be waken up at the beginning of a whole second, which will typically
exhibit as a "lag" on second number.  Second, because we sleep for whole
second, and the refresh process would take some time, the error would
accumulate from time to time, making the lag variable.

Make grdc(6) to use time(3) to get time only at the beginning, and sample
time in CLOCK_REALTIME_FAST granularity after refreshing, and use the
nanosecond part to caculate how much time we want to sleep.

PR:		bin/120813
MFC after:	1 month
2010-02-10 18:20:20 +00:00

270 lines
4.3 KiB
C

/*
* Grand digital clock for curses compatible terminals
* Usage: grdc [-st] [n] -- run for n seconds (default infinity)
* Flags: -s: scroll
* -t: output time in 12-hour format
*
*
* modified 10-18-89 for curses (jrl)
* 10-18-89 added signal handling
*
* modified 03-25-03 for 12 hour option
* - Samy Al Bahra <samy@kerneled.com>
*
* $FreeBSD$
*/
#include <err.h>
#include <time.h>
#include <signal.h>
#include <ncurses.h>
#include <stdlib.h>
#ifndef NONPOSIX
#include <unistd.h>
#endif
#define YBASE 10
#define XBASE 10
#define XLENGTH 58
#define YDEPTH 7
/* it won't be */
time_t now; /* yeah! */
struct tm *tm;
short disp[11] = {
075557, 011111, 071747, 071717, 055711,
074717, 074757, 071111, 075757, 075717, 002020
};
long old[6], next[6], new[6], mask;
volatile sig_atomic_t sigtermed;
int hascolor = 0;
void set(int, int);
void standt(int);
void movto(int, int);
void sighndl(int);
void usage(void);
void sighndl(signo)
int signo;
{
sigtermed=signo;
}
int
main(argc, argv)
int argc;
char **argv;
{
struct timespec ts;
long t, a;
int i, j, s, k;
int n;
int ch;
int scrol;
int t12;
t12 = scrol = 0;
while ((ch = getopt(argc, argv, "ts")) != -1)
switch (ch) {
case 's':
scrol = 1;
break;
case 't':
t12 = 1;
break;
case '?':
default:
usage();
/* NOTREACHED */
}
argc -= optind;
argv += optind;
if (argc > 1) {
usage();
/* NOTREACHED */
}
if (argc > 0)
n = atoi(*argv);
else
n = 0;
initscr();
signal(SIGINT,sighndl);
signal(SIGTERM,sighndl);
signal(SIGHUP,sighndl);
cbreak();
noecho();
curs_set(0);
hascolor = has_colors();
if(hascolor) {
start_color();
init_pair(1, COLOR_BLACK, COLOR_RED);
init_pair(2, COLOR_RED, COLOR_BLACK);
init_pair(3, COLOR_WHITE, COLOR_BLACK);
attrset(COLOR_PAIR(2));
}
clear();
refresh();
if(hascolor) {
attrset(COLOR_PAIR(3));
mvaddch(YBASE - 2, XBASE - 3, ACS_ULCORNER);
hline(ACS_HLINE, XLENGTH);
mvaddch(YBASE - 2, XBASE - 2 + XLENGTH, ACS_URCORNER);
mvaddch(YBASE + YDEPTH - 1, XBASE - 3, ACS_LLCORNER);
hline(ACS_HLINE, XLENGTH);
mvaddch(YBASE + YDEPTH - 1, XBASE - 2 + XLENGTH, ACS_LRCORNER);
move(YBASE - 1, XBASE - 3);
vline(ACS_VLINE, YDEPTH);
move(YBASE - 1, XBASE - 2 + XLENGTH);
vline(ACS_VLINE, YDEPTH);
attrset(COLOR_PAIR(2));
}
time(&now);
do {
mask = 0;
tm = localtime(&now);
set(tm->tm_sec%10, 0);
set(tm->tm_sec/10, 4);
set(tm->tm_min%10, 10);
set(tm->tm_min/10, 14);
if (t12) {
if (tm->tm_hour > 12) {
tm->tm_hour -= 12;
mvaddstr(YBASE + 5, XBASE + 52, "PM");
} else {
if (tm->tm_hour == 0)
tm->tm_hour = 12;
mvaddstr(YBASE + 5, XBASE + 52, "AM");
}
}
set(tm->tm_hour%10, 20);
set(tm->tm_hour/10, 24);
set(10, 7);
set(10, 17);
for(k=0; k<6; k++) {
if(scrol) {
for(i=0; i<5; i++)
new[i] = (new[i]&~mask) | (new[i+1]&mask);
new[5] = (new[5]&~mask) | (next[k]&mask);
} else
new[k] = (new[k]&~mask) | (next[k]&mask);
next[k] = 0;
for(s=1; s>=0; s--) {
standt(s);
for(i=0; i<6; i++) {
if((a = (new[i]^old[i])&(s ? new : old)[i]) != 0) {
for(j=0,t=1<<26; t; t>>=1,j++) {
if(a&t) {
if(!(a&(t<<1))) {
movto(YBASE + i, XBASE + 2*j);
}
addstr(" ");
}
}
}
if(!s) {
old[i] = new[i];
}
}
if(!s) {
refresh();
}
}
}
movto(6, 0);
refresh();
clock_gettime(CLOCK_REALTIME_FAST, &ts);
if (ts.tv_sec == now) {
if (ts.tv_nsec > 0) {
ts.tv_sec = 0;
ts.tv_nsec = 1000000000 - ts.tv_nsec;
} else {
ts.tv_sec = 1;
ts.tv_nsec = 0;
}
nanosleep(&ts, NULL);
now = ts.tv_sec + 1;
} else
now = ts.tv_sec;
if (sigtermed) {
standend();
clear();
refresh();
endwin();
errx(1, "terminated by signal %d", (int)sigtermed);
}
} while(--n);
standend();
clear();
refresh();
endwin();
return(0);
}
void
set(int t, int n)
{
int i, m;
m = 7<<n;
for(i=0; i<5; i++) {
next[i] |= ((disp[t]>>(4-i)*3)&07)<<n;
mask |= (next[i]^old[i])&m;
}
if(mask&m)
mask |= m;
}
void
standt(int on)
{
if (on) {
if(hascolor) {
attron(COLOR_PAIR(1));
} else {
attron(A_STANDOUT);
}
} else {
if(hascolor) {
attron(COLOR_PAIR(2));
} else {
attroff(A_STANDOUT);
}
}
}
void
movto(int line, int col)
{
move(line, col);
}
void
usage(void)
{
(void)fprintf(stderr, "usage: grdc [-st] [n]\n");
exit(1);
}