P25 C4FM Decoder - ArrayIndexOutOfBounds Exception

[DSheirer]

This is occurring infrequently on 0.5.0-alpha7 using an RTL dongle with polyphase channelizer and P25 C4FM decoder. It's happening for both 1-channel and 2-channel output processors.

Task

Update the InterpolatingSampleBuffer to not let the interpolation offset fall below zero.

20220314 112641.965 [sdrtrunk polyphase channel] ERROR i.g.d.d.f.c.o.OneChannelOutputProcessor - Error extracting channel samples from one polyphase channel results buffer [996MB/2GB 39%]
java.lang.ArrayIndexOutOfBoundsException: Index -36 out of bounds for length 129
at io.github.dsheirer.dsp.filter.interpolator.RealInterpolator.filter(RealInterpolator.java:49)
at io.github.dsheirer.dsp.psk.InterpolatingSampleBuffer.getInphase(InterpolatingSampleBuffer.java:190)
at io.github.dsheirer.dsp.psk.InterpolatingSampleBuffer.getCurrentSample(InterpolatingSampleBuffer.java:162)
at io.github.dsheirer.dsp.psk.DQPSKDecisionDirectedDemodulator.calculateSymbol(DQPSKDecisionDirectedDemodulator.java:54)
at io.github.dsheirer.dsp.psk.PSKDemodulator.receive(PSKDemodulator.java:117)
at io.github.dsheirer.dsp.psk.PSKDemodulator.receive(PSKDemodulator.java:93)
at io.github.dsheirer.module.decode.p25.phase1.P25P1DecoderC4FM.receive(P25P1DecoderC4FM.java:114)
at io.github.dsheirer.module.decode.p25.phase1.P25P1DecoderC4FM.receive(P25P1DecoderC4FM.java:44)
at io.github.dsheirer.sample.Broadcaster.broadcast(Broadcaster.java:152)
at io.github.dsheirer.sample.Broadcaster.receive(Broadcaster.java:59)
at io.github.dsheirer.dsp.filter.channelizer.PolyphaseChannelSource.receive(PolyphaseChannelSource.java:104)
at io.github.dsheirer.dsp.filter.channelizer.PolyphaseChannelSource.receive(PolyphaseChannelSource.java:31)
at io.github.dsheirer.dsp.filter.channelizer.output.OneChannelOutputProcessor.process(OneChannelOutputProcessor.java:100)
at io.github.dsheirer.dsp.filter.channelizer.output.ChannelOutputProcessor.lambda$new$0(ChannelOutputProcessor.java:50)
at io.github.dsheirer.util.Dispatcher$Processor.run(Dispatcher.java:180)
at java.base/java.lang.Thread.run(Unknown Source)