+ #include <limits.h>
+
+ const char *
+ battery_perc(const char *bat)
+ {
+ int perc;
+ char path[PATH_MAX];
+
+ if (esnprintf(path, sizeof(path),
+ "/sys/class/power_supply/%s/capacity",
+ bat) < 0) {
+ return NULL;
+ }
+ if (pscanf(path, "%d", &perc) != 1) {
+ return NULL;
+ }
+
+ return bprintf("%d%%", perc);
+ }
+
+ const char *
+ battery_state(const char *bat)
+ {
+ static struct {
+ char *state;
+ char *symbol;
+ } map[] = {
+ { "Charging", "+" },
+ { "Discharging", "-" },
+ };
+ size_t i;
+ char path[PATH_MAX], state[12];
+
+ if (esnprintf(path, sizeof(path),
+ "/sys/class/power_supply/%s/status",
+ bat) < 0) {
+ return NULL;
+ }
+ if (pscanf(path, "%12s", state) != 1) {
+ return NULL;
+ }
+
+ for (i = 0; i < LEN(map); i++) {
+ if (!strcmp(map[i].state, state)) {
+ break;
+ }
+ }
+ return (i == LEN(map)) ? "?" : map[i].symbol;
+ }
+
+ const char *
+ battery_remaining(const char *bat)
+ {
+ int charge_now, current_now, m, h;
+ float timeleft;
+ char path[PATH_MAX], state[12];
+
+ if (esnprintf(path, sizeof(path),
+ "/sys/class/power_supply/%s/status",
+ bat) < 0) {
+ return NULL;
+ }
+ if (pscanf(path, "%12s", state) != 1) {
+ return NULL;
+ }