Add getChannelIndexForType to AudioChannelSet class

modules/juce_audio_processors/processors/juce_AudioChannelSet.cpp

@@ -135,6 +135,20 @@ AudioChannelSet::ChannelType AudioChannelSet::getTypeOfChannel (int index) const
     return static_cast<ChannelType> (bit);
 }
 
+int AudioChannelSet::getChannelIndexForType (AudioChannelSet::ChannelType type) const noexcept
+{
+    int idx = 0;
+    for (int bit = channels.findNextSetBit (0); bit >= 0; bit = channels.findNextSetBit (bit + 1))
+    {
+        if (static_cast<ChannelType> (bit) == type)
+            return idx;
+
+        idx++;
+    }
+
+    return -1;
+}
+
 Array<AudioChannelSet::ChannelType> AudioChannelSet::getChannelTypes() const
 {
     Array<ChannelType> result;

modules/juce_audio_processors/processors/juce_AudioChannelSet.h

@@ -166,6 +166,10 @@ public:
     /** Returns the type of one of the channels in the set, by index. */
     ChannelType getTypeOfChannel (int channelIndex) const noexcept;
 
+    /** Returns the index for a particular channel-type.
+        Will return -1 if the this set does not contain a channel of this type. */
+    int getChannelIndexForType (ChannelType type) const noexcept;
+
     /** Returns a string containing a whitespace-separated list of speaker types
         corresponding to each channel. For example in a 5.1 arrangement,
         the string may be "L R C Lfe Ls Rs". If the speaker arrangement is unknown,