Merge individual Battery.[ch] files into Platform.[ch]

Consistent with everything else involving platform-specific
calls from core htop code.

darwin/Platform.c

@@ -26,6 +26,10 @@ in the source distribution for its full text.
 #include <math.h>
 #include <stdlib.h>
 
+#include <CoreFoundation/CoreFoundation.h>
+#include <CoreFoundation/CFString.h>
+#include <IOKit/ps/IOPowerSources.h>
+#include <IOKit/ps/IOPSKeys.h>
 
 ProcessField Platform_defaultFields[] = { PID, USER, PRIORITY, NICE, M_SIZE, M_RESIDENT, STATE, PERCENT_CPU, PERCENT_MEM, TIME, COMM, 0 };
 
@@ -341,3 +345,67 @@ bool Platform_getNetworkIO(unsigned long int* bytesReceived,
    *packetsTransmitted = 0;
    return false;
 }
+
+void Platform_getBattery(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);
+}