AU: Use slightly more readable channel type

modules/juce_audio_plugin_client/AU/juce_AU_Wrapper.mm

@@ -2051,10 +2051,12 @@ private:
         addSupportedLayoutTags();
 
         for (int i = 0; i < enabledInputs; ++i)
-            if ((err = syncAudioUnitWithChannelSet (true,  i, juceFilter->getChannelLayoutOfBus (true,  i))) != noErr) return err;
+            if ((err = syncAudioUnitWithChannelSet (true,  i, juceFilter->getChannelLayoutOfBus (true,  i))) != noErr)
+                return err;
 
         for (int i = 0; i < enabledOutputs; ++i)
-            if ((err = syncAudioUnitWithChannelSet (false, i, juceFilter->getChannelLayoutOfBus (false, i))) != noErr) return err;
+            if ((err = syncAudioUnitWithChannelSet (false, i, juceFilter->getChannelLayoutOfBus (false, i))) != noErr)
+                return err;
 
         return noErr;
     }
@@ -2177,7 +2179,7 @@ private:
            #endif
 
             // add discrete layout tags
-            int n = bus->getMaxSupportedChannels(maxChannelsToProbeFor());
+            int n = bus->getMaxSupportedChannels (maxChannelsToProbeFor());
 
             for (int ch = 0; ch < n; ++ch)
             {

modules/juce_audio_processors/format_types/juce_AU_Shared.h

@@ -353,11 +353,22 @@ struct AudioUnitHelpers
         auto defaultInputs  = processor.getChannelCountOfBus (true,  0);
         auto defaultOutputs = processor.getChannelCountOfBus (false, 0);
 
-        SortedSet<int> supportedChannels;
+        struct Channels
+        {
+            SInt16 ins, outs;
+
+            std::pair<SInt16, SInt16> makePair() const noexcept { return std::make_pair (ins, outs); }
+
+            bool operator<  (const Channels& other) const noexcept { return makePair() <  other.makePair(); }
+            bool operator== (const Channels& other) const noexcept { return makePair() == other.makePair(); }
+        };
+
+        SortedSet<Channels> supportedChannels;
 
         // add the current configuration
         if (defaultInputs != 0 || defaultOutputs != 0)
-            supportedChannels.add ((defaultInputs << 16) | defaultOutputs);
+            supportedChannels.add ({ static_cast<SInt16> (defaultInputs),
+                                     static_cast<SInt16> (defaultOutputs) });
 
         for (auto inChanNum = hasMainInputBus ? 1 : 0; inChanNum <= (hasMainInputBus ? maxNumChanToCheckFor : 0); ++inChanNum)
         {
@@ -375,19 +386,16 @@ struct AudioUnitHelpers
                     if (! isNumberOfChannelsSupported (outBus, outChanNum, outLayout))
                         continue;
 
-                supportedChannels.add (((hasMainInputBus  ? outLayout.getMainInputChannels()  : 0) << 16)
-                                      | (hasMainOutputBus ? outLayout.getMainOutputChannels() : 0));
+                supportedChannels.add ({ static_cast<SInt16> (hasMainInputBus  ? outLayout.getMainInputChannels()  : 0),
+                                         static_cast<SInt16> (hasMainOutputBus ? outLayout.getMainOutputChannels() : 0) });
             }
         }
 
         auto hasInOutMismatch = false;
 
-        for (auto supported : supportedChannels)
+        for (const auto& supported : supportedChannels)
         {
-            auto numInputs  = (supported >> 16) & 0xffff;
-            auto numOutputs = (supported >> 0)  & 0xffff;
-
-            if (numInputs != numOutputs)
+            if (supported.ins != supported.outs)
             {
                 hasInOutMismatch = true;
                 break;
@@ -398,9 +406,10 @@ struct AudioUnitHelpers
 
         for (auto inChanNum = hasMainInputBus ? 1 : 0; inChanNum <= (hasMainInputBus ? maxNumChanToCheckFor : 0); ++inChanNum)
         {
-            auto channelConfiguration = (inChanNum << 16) | (hasInOutMismatch ? defaultOutputs : inChanNum);
+            Channels channelConfiguration { static_cast<SInt16> (inChanNum),
+                                            static_cast<SInt16> (hasInOutMismatch ? defaultOutputs : inChanNum) };
 
-            if (! supportedChannels.contains (channelConfiguration))
+            if (supportedChannels.contains (channelConfiguration))
             {
                 hasUnsupportedInput = true;
                 break;
@@ -409,25 +418,23 @@ struct AudioUnitHelpers
 
         for (auto outChanNum = hasMainOutputBus ? 1 : 0; outChanNum <= (hasMainOutputBus ? maxNumChanToCheckFor : 0); ++outChanNum)
         {
-            auto channelConfiguration = ((hasInOutMismatch ? defaultInputs : outChanNum) << 16) | outChanNum;
+            Channels channelConfiguration { static_cast<SInt16> (hasInOutMismatch ? defaultInputs : outChanNum),
+                                            static_cast<SInt16> (outChanNum) };
 
-            if (! supportedChannels.contains (channelConfiguration))
+            if (supportedChannels.contains (channelConfiguration))
             {
                 hasUnsupportedOutput = true;
                 break;
             }
         }
 
-        for (auto supported : supportedChannels)
+        for (const auto& supported : supportedChannels)
         {
-            auto numInputs  = (supported >> 16) & 0xffff;
-            auto numOutputs = (supported >> 0)  & 0xffff;
-
             AUChannelInfo info;
 
             // see here: https://developer.apple.com/library/mac/documentation/MusicAudio/Conceptual/AudioUnitProgrammingGuide/TheAudioUnit/TheAudioUnit.html
-            info.inChannels  = static_cast<SInt16> (hasMainInputBus  ? (hasUnsupportedInput  ? numInputs :  (hasInOutMismatch && (! hasUnsupportedOutput) ? -2 : -1)) : 0);
-            info.outChannels = static_cast<SInt16> (hasMainOutputBus ? (hasUnsupportedOutput ? numOutputs : (hasInOutMismatch && (! hasUnsupportedInput)  ? -2 : -1)) : 0);
+            info.inChannels  = static_cast<SInt16> (hasMainInputBus  ? (hasUnsupportedInput  ? supported.ins  : (hasInOutMismatch && (! hasUnsupportedOutput) ? -2 : -1)) : 0);
+            info.outChannels = static_cast<SInt16> (hasMainOutputBus ? (hasUnsupportedOutput ? supported.outs : (hasInOutMismatch && (! hasUnsupportedInput)  ? -2 : -1)) : 0);
 
             if (info.inChannels == -2 && info.outChannels == -2)
                 info.inChannels = -1;