First commit

Makefile

@@ -0,0 +1,5 @@
+light: light.c
+	$(CC) light.c $(CFLAGS) -lm -o light
+
+install: light
+	install light /usr/local/bin

light.c

@@ -0,0 +1,75 @@
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <math.h>
+
+#define BRIGHTNESS     "/sys/class/backlight/amdgpu_bl1/brightness"
+#define MAX_BRIGHTNESS "/sys/class/backlight/amdgpu_bl1/max_brightness"
+
+int   brightness;
+char  brightness_str[8];
+FILE *brightness_fp;
+
+int   max_brightness;
+char  max_brightness_str[8];
+FILE *max_brightness_fp;
+
+int new_brightness;
+
+int normalize(int);
+
+int main(int argc, char* argv[])
+{
+	brightness_fp     = fopen(BRIGHTNESS, "w+");
+	max_brightness_fp = fopen(MAX_BRIGHTNESS, "r");
+
+	fgets(brightness_str, 8, brightness_fp);
+	brightness = atoi(brightness_str);
+
+	fgets(max_brightness_str, 8, max_brightness_fp);
+	max_brightness = atoi(max_brightness_str);
+
+	if (argc > 1) {
+		char *arg = argv[1];
+		if (arg[strlen(arg) - 1] == '%') {
+			int    percent = brightness * 100 / max_brightness;
+			arg[strlen(arg) - 1] = 0;
+			if (arg[0] == '+')
+				percent += atoi(++arg);
+			else if (arg[0] == '-')
+				percent -= atoi(++arg);
+			else
+				percent = atoi(arg);
+			new_brightness = ceil((float) percent * 255 / 100);
+		}
+		else {
+			if (arg[0] == '+')
+				new_brightness = brightness + atoi(++arg);
+			else if (arg[0] == '-')
+				new_brightness = brightness - atoi(++arg);
+			else
+				new_brightness = atoi(arg);
+		}
+	}
+	else
+		new_brightness = brightness;
+
+	new_brightness = normalize(new_brightness);
+
+	if (new_brightness != brightness) {
+		sprintf(brightness_str, "%i", new_brightness);
+		fputs(brightness_str, brightness_fp);
+	}
+
+	printf("%i/%i (%i%%)\n", new_brightness, max_brightness, new_brightness * 100 / max_brightness);
+}
+
+int normalize(int brightness)
+{
+	if (brightness < 0)
+		return 0;
+	else if (brightness > max_brightness)
+		return max_brightness;
+	else
+		return brightness;
+}