seperate out the battery funcs

src/battery.c

@@ -0,0 +1,54 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdbool.h>
+#include <unistd.h>
+
+#include "utils.h"
+
+#include "config.h"
+
+char
+*battery_percent(void)
+{
+  char *r, c, *d;
+  int i;
+  FILE *f;
+
+  /* open up the battery capacity for reading */
+  d = concat(battery_dir, "/capacity");
+  f = fopen(d, "r");
+  free(d);
+
+  /* create enough space for the battery percentage */
+  r = calloc(4, sizeof(char));
+
+  /* read in the battery percentage */
+  i = 0;
+  while ((c = getc(f)) && i < 4) {
+    /* make sure to replace the newline with a string terminator */
+    if (c == '\n') {
+      r[i] = '\0';
+      break;
+    }
+    r[i] = c;
+    i++;
+  }
+
+  fclose(f);
+  return r;
+}
+
+bool
+plugged_in(char *fn)
+{
+  FILE *f;
+  char buf[1];
+
+  f = fopen(fn, "r");
+  if (read(fileno(f), buf, 1) < 0) {
+    return -1;
+  }
+  fclose(f);
+
+  return buf[0] - '0';
+}