Resampler: Fix gapless output

The resampler wasn't being given enough room to flush its final output,
so a function was added to determine the current output latency, and
more sample data is requested, allowing the full output flush to occur.

Signed-off-by: Christopher Snowhill <kode54@gmail.com>

Audio/Chain/ConverterNode.mm

@@ -754,6 +754,9 @@ tryagain:
 		size_t outputDone = 0;
 
 		if(!skipResampler) {
+			// This is needed at least for the flush, or else there won't be room for it
+			ioNumberPackets += ((r8bstate *)_r8bstate)->latency();
+
 #ifdef _DEBUG
 			[BadSampleCleaner cleanSamples:(float *)(((uint8_t *)inputBuffer) + inpOffset)
 			                        amount:inputSamples * floatFormat.mChannelsPerFrame

Audio/ThirdParty/r8bstate.h

@@ -43,6 +43,10 @@ struct r8bstate {
 		delete[] Resamps;
 	}
 
+	double latency() {
+		return ((double)inProcessed * sampleRatio) - (double)outProcessed;
+	}
+
 	int resample(const float *input, size_t inCount, size_t *inDone, float *output, size_t outMax) {
 		int ret = 0;
 		int i;