darwin/Battery.c


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#include "Battery.h"

#include <math.h>

#include <CoreFoundation/CoreFoundation.h>
#include <CoreFoundation/CFString.h>
#include <IOKit/ps/IOPowerSources.h>
#include <IOKit/ps/IOPSKeys.h>

void Battery_getData(double* level, ACPresence* isOnAC) {
   CFTypeRef power_sources = IOPSCopyPowerSourcesInfo();

   *level = NAN;
   *isOnAC = AC_ERROR;

   if(NULL == power_sources) {
      return;
   }

   CFArrayRef list = IOPSCopyPowerSourcesList(power_sources);
   CFDictionaryRef battery = NULL;
   int len;

   if(NULL == list) {
      CFRelease(power_sources);

      return;
   }

   len = CFArrayGetCount(list);

   /* Get the battery */
   for(int i = 0; i < len && battery == NULL; ++i) {
      CFDictionaryRef candidate = IOPSGetPowerSourceDescription(power_sources,
                                    CFArrayGetValueAtIndex(list, i)); /* GET rule */
      CFStringRef type;

      if(NULL != candidate) {
         type = (CFStringRef) CFDictionaryGetValue(candidate,
                  CFSTR(kIOPSTransportTypeKey)); /* GET rule */

         if(kCFCompareEqualTo == CFStringCompare(type, CFSTR(kIOPSInternalType), 0)) {
            CFRetain(candidate);
            battery = candidate;
         }
      }
   }

   if(NULL != battery) {
      /* Determine the AC state */
      CFStringRef power_state = CFDictionaryGetValue(battery, CFSTR(kIOPSPowerSourceStateKey));

      *isOnAC = (kCFCompareEqualTo == CFStringCompare(power_state, CFSTR(kIOPSACPowerValue), 0))
               ? AC_PRESENT
               : AC_ABSENT;

      /* Get the percentage remaining */
      double current;
      double max;

      CFNumberGetValue(CFDictionaryGetValue(battery, CFSTR(kIOPSCurrentCapacityKey)),
               kCFNumberDoubleType, &current);
      CFNumberGetValue(CFDictionaryGetValue(battery, CFSTR(kIOPSMaxCapacityKey)),
               kCFNumberDoubleType, &max);

      *level = (current * 100.0) / max;

      CFRelease(battery);
   }

   CFRelease(list);
   CFRelease(power_sources);
}