+ #include <limits.h>
+ #include <stdint.h>
+ #include <unistd.h>
+
+ static const char *
+ pick(const char *bat, const char *f1, const char *f2, char *path,
+ size_t length)
+ {
+ if (esnprintf(path, length, f1, bat) > 0 &&
+ access(path, R_OK) == 0) {
+ return f1;
+ }
+
+ if (esnprintf(path, length, f2, bat) > 0 &&
+ access(path, R_OK) == 0) {
+ return f2;
+ }
+
+ return NULL;
+ }
+
+ 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)
+ {
+ uintmax_t charge_now, current_now, m, h;
+ double 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;
+ }
+
+ if (!pick(bat, "/sys/class/power_supply/%s/charge_now",
+ "/sys/class/power_supply/%s/energy_now", path,
+ sizeof(path)) ||
+ pscanf(path, "%ju", &charge_now) < 0) {
+ return NULL;
+ }
+
+ if (!strcmp(state, "Discharging")) {
+ if (!pick(bat, "/sys/class/power_supply/%s/current_now",
+ "/sys/class/power_supply/%s/power_now", path,
+ sizeof(path)) ||
+ pscanf(path, "%ju", ¤t_now) < 0) {
+ return NULL;
+ }
+
+ if (current_now == 0) {
+ return NULL;
+ }
+
+ timeleft = (double)charge_now / (double)current_now;
+ h = timeleft;
+ m = (timeleft - (double)h) * 60;
+
+ return bprintf("%juh %jum", h, m);
+ }
+
+ return "";
+ }