Add print_cpu_usage

1 files changed, 50 insertions, 0 deletions

diff --git a/src/print_cpu_usage.c b/src/print_cpu_usage.c
new file mode 100644
index 0000000..d80693d
--- /dev/null
+++ b/src/print_cpu_usage.c
@@ -0,0 +1,50 @@
+// vim:sw=8:sts=8:ts=8:expandtab
+#include <stdlib.h>
+#include <limits.h>
+#include <stdio.h>
+#include <string.h>
+
+#include "i3status.h"
+
+static int prev_total = 0;
+static int prev_idle  = 0;
+
+/*
+ * Reads the CPU utilization from /proc/stat and returns the usage as a
+ * percentage.
+ *
+ */
+void print_cpu_usage(const char *format) { 
+        const char *walk;
+        char buf[1024];
+        int curr_user, curr_nice, curr_system, curr_idle, curr_total;
+        int diff_idle, diff_total, diff_usage;
+
+#if defined(LINUX)
+        static char statpath[512];
+        strcpy(statpath, "/proc/stat");
+        if (!slurp(statpath, buf, sizeof(buf)))
+                die("could not read %s\n", statpath);
+
+        if (sscanf(buf, "cpu %d %d %d %d", &curr_user, &curr_nice, &curr_system, &curr_idle) != 4)
+                die("could not read cpu utilization\n");
+
+        curr_total = curr_user + curr_nice + curr_system + curr_idle;
+        diff_idle  = curr_idle - prev_idle;
+        diff_total = curr_total - prev_total;
+        diff_usage = (1000 * (diff_total - diff_idle)/diff_total + 5)/10;
+        prev_total = curr_total;
+        prev_idle  = curr_idle;
+#endif
+        for (walk = format; *walk != '\0'; walk++) {
+                if (*walk != '%') {
+                        putchar(*walk);
+                        continue;
+                }
+
+                if (strncmp(walk+1, "usage", strlen("usage")) == 0) {
+                        printf("%02d%%", diff_usage);
+                        walk += strlen("usage");
+                }
+        }
+}