Mac battery percentage

Blarged

macrumors newbie
Original poster
Apr 14, 2008
24
0
Hi, looking for a light-weight method of getting the current battery charge left percentage. To determine whether the computer is running of AC or DC power I use the
Code:
IOPSGetProvidingPowerSourceType
, however, I am struggling with the battery percentage.

I have also considered using
Code:
pmset -g ps
but would prefer a C++ solution... any ideas?

I am not entirely certain how to go about using...
kIOPSCurrentCapacityKey and kIOPSMaxCapacityKey
 

Blarged

macrumors newbie
Original poster
Apr 14, 2008
24
0
I got it...

thanks to: http://lists.omnipotent.net/pipermail/lcdproc/2006-January/010417.html

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

int main (int argc, const char * argv[]) {
	CFTypeRef blob = IOPSCopyPowerSourcesInfo();
	CFArrayRef sources = IOPSCopyPowerSourcesList(blob);
	
	CFDictionaryRef pSource = NULL;
	const void *psValue;
	
	int numOfSources = CFArrayGetCount(sources);
	if (numOfSources == 0) return 1;
	
	for (int i = 0 ; i < numOfSources ; i++)
	{
		pSource = IOPSGetPowerSourceDescription(blob, CFArrayGetValueAtIndex(sources, i));
		if (!pSource) return 2;
		
		psValue = (CFStringRef)CFDictionaryGetValue(pSource, CFSTR(kIOPSNameKey));
		
		int curCapacity = 0;
		int maxCapacity = 0;
		int percent;
		
		psValue = CFDictionaryGetValue(pSource, CFSTR(kIOPSCurrentCapacityKey));
		CFNumberGetValue((CFNumberRef)psValue, kCFNumberSInt32Type, &curCapacity);
		
		psValue = CFDictionaryGetValue(pSource, CFSTR(kIOPSMaxCapacityKey));
		CFNumberGetValue((CFNumberRef)psValue, kCFNumberSInt32Type, &maxCapacity);
		
		percent = (int)((double)curCapacity/(double)maxCapacity * 100);
		
		printf ("powerSource %d of %d: percent: %d/%d %d\n", i, CFArrayGetCount(sources), curCapacity, maxCapacity, percent);

	}
	
    return 0;
}
for my attempt to make it as light-weight as possible, this is the final function:
Code:
int BatteryAC::GetBatteryPercent(int *piBatteryPercent)
{

	CFTypeRef blob = IOPSCopyPowerSourcesInfo();
	CFArrayRef sources = IOPSCopyPowerSourcesList(blob);
	
	CFDictionaryRef pSource = NULL;
	const void *psValue;
	
	if (CFArrayGetCount(sources) == 0)
		return 0;	// Could not retrieve battery information.  System may not have a battery.

	pSource = IOPSGetPowerSourceDescription(blob, CFArrayGetValueAtIndex(sources, i));
	psValue = (CFStringRef)CFDictionaryGetValue(pSource, CFSTR(kIOPSNameKey));
	
	int curCapacity = 0;
	int maxCapacity = 0;
	int percent;
	
	psValue = CFDictionaryGetValue(pSource, CFSTR(kIOPSCurrentCapacityKey));
	CFNumberGetValue((CFNumberRef)psValue, kCFNumberSInt32Type, &curCapacity);
	
	psValue = CFDictionaryGetValue(pSource, CFSTR(kIOPSMaxCapacityKey));
	CFNumberGetValue((CFNumberRef)psValue, kCFNumberSInt32Type, &maxCapacity);
	
	*piBatteryPercent = (int)((double)curCapacity/(double)maxCapacity * 100);
	
	if (piBatteryPercent < 0 || piBatteryPercent > 100)
		return -1;	// Could not retrieve the battery information
	else
		return 1;	// Success
}
 
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