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#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <poll.h>
#define FIFO_PATH "/tmp/brightnessd-fifo"
#define BRIGHT_FILE "/sys/class/backlight/radeon_bl0/brightness"
#define DELAY 5
#define STEP 1
#define BIG_STEP 10
int get_now(FILE *f)
{
char buffer[4096]; /* FIXME: magic constant is icky */
/* FIXME: check return value for error */
fgets(buffer, sizeof(buffer), f);
return atoi(buffer);
}
int brightness_within_bounds(int bright, int lower, int upper)
{
/* FIXME: make a horrible but funny ternary statement */
if (bright < lower)
return lower;
if (bright > upper)
return upper;
return bright;
}
int main(int argc, char **argv)
{
int target = 0;
int now = 0;
FILE *f = NULL;
char buffer[4]; /* size 4 because max bright is 255, plus null terminator */
/* Open brightness file */
if ((f = fopen(BRIGHT_FILE, "w+")) == NULL)
{
perror("fopen");
exit(EXIT_FAILURE);
}
now = get_now(f);
target = now;
/* create and open a FIFO */
remove(FIFO_PATH);
mkfifo(FIFO_PATH, 0666);
chmod(FIFO_PATH, 0666);
/* FIXME : check return val */
int fifo = open(FIFO_PATH, O_RDWR);
struct pollfd fds[1];
fds[0].fd = fifo;
fds[0].events = POLLIN;
int delay = -1;
while(1)
{
poll(fds, 1, delay);
if (fds[0].revents & POLLIN)
{
delay = DELAY;
read(fifo, buffer, sizeof(buffer));
switch(buffer[0])
{
case '+':
target += BIG_STEP;
break;
case '-':
target -= BIG_STEP;
break;
default:
target = atoi(buffer);
break;
}
target = brightness_within_bounds(target, 1, 255);
}
if (now < target) {
now += STEP;
if (now > target)
now = target;
} else if (now > target) {
now -= STEP;
if (now < target)
now = target;
} else if (now == target) {
delay = -1;
}
fprintf(f, "%d\n", now);
rewind(f);
}
close(fifo);
remove(FIFO_PATH);
return 0;
}
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