Split into multiple files

For multiple reasons the program is now split:
- Make future porting to OpenBSD easier
- Assign header includes to individiual functions
- Make future program extensions easier
- Recompile only changed parts

cpu.c

@@ -0,0 +1,62 @@
+#include <stdio.h>
+#include <string.h>
+
+#include "util.h"
+
+const char *
+cpu_freq(void)
+{
+	int freq;
+
+	return (pscanf("/sys/devices/system/cpu/cpu0/cpufreq/scaling_cur_freq",
+	               "%i", &freq) == 1) ?
+	       bprintf("%d", (freq + 500) / 1000) : NULL;
+}
+
+const char *
+cpu_perc(void)
+{
+	int perc;
+	static long double a[7];
+	static int valid;
+	long double b[7];
+
+	memcpy(b, a, sizeof(b));
+	if (pscanf("/proc/stat", "%*s %Lf %Lf %Lf %Lf %Lf %Lf %Lf", &a[0], &a[1], &a[2],
+	           &a[3], &a[4], &a[5], &a[6]) != 7) {
+		return NULL;
+	}
+	if (!valid) {
+		valid = 1;
+		return NULL;
+	}
+
+	perc = 100 * ((b[0]+b[1]+b[2]+b[5]+b[6]) - (a[0]+a[1]+a[2]+a[5]+a[6])) /
+	       ((b[0]+b[1]+b[2]+b[3]+b[4]+b[5]+b[6]) - (a[0]+a[1]+a[2]+a[3]+a[4]+a[5]+a[6]));
+
+	return bprintf("%d", perc);
+}
+
+const char *
+cpu_iowait(void)
+{
+	int perc;
+	static int valid;
+	static long double a[7];
+	long double b[7];
+
+	memcpy(b, a, sizeof(b));
+	if (pscanf("/proc/stat", "%*s %Lf %Lf %Lf %Lf %Lf %Lf %Lf", &a[0], &a[1], &a[2],
+	           &a[3], &a[4], &a[5], &a[6]) != 7) {
+		return NULL;
+	}
+	if (!valid) {
+		valid = 1;
+		return NULL;
+	}
+
+	perc = 100 * ((b[4]) - (a[4])) /
+	       ((b[0]+b[1]+b[2]+b[3]+b[4]+b[5]+b[6]) - (a[0]+a[1]+a[2]+a[3]+a[4]+a[5]+a[6]));
+
+	return bprintf("%d", perc);
+}