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#include <stdio.h>
#include <stdlib.h>
#include <sys/stat.h>
#include <unistd.h>
#include <fcntl.h>
#include "vlock.h"
static unsigned char lines, columns;
static void *screen_buf = NULL;
static int vcs;
void clear_screen(void)
{
struct stat s_buf;
int i;
char path[16];
if (fstat(0, &s_buf)==-1) {
return;
}
if (!S_ISCHR(s_buf.st_mode)) {
return;
}
if ((s_buf.st_rdev / 256) != 4) {
return;
}
i = s_buf.st_rdev % 256;
sprintf(path, "/dev/vcsa%d", i);
vcs = open(path, O_RDWR);
if (vcs<0) {
return;
}
if (read(vcs, &columns, 1)!=1) {
close(vcs);
return;
}
if (read(vcs, &lines, 1)!=1) {
close(vcs);
return;
}
screen_buf = malloc(2*lines*columns+2);
if (!screen_buf) {
close(vcs);
return;
}
if (read(vcs, screen_buf, 2*lines*columns+2) != 2*lines*columns+2) {
free(screen_buf);
screen_buf=NULL;
close(vcs);
return;
}
write(1, "\33[H\33[J", 6); /* There's no need to use ncurses */
fflush(stdout);
}
void restore_screen(void)
{
if (screen_buf) {
lseek(vcs, 0, SEEK_SET);
write(vcs, &columns, 1);
write(vcs, &lines, 1);
write(vcs, screen_buf, 2*lines*columns+2);
close(vcs);
}
}
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