Workaround for bug in RtAudio when first channel not equal to 0

src/lasp/device/lasp_rtaudiodaq.cpp

@@ -1,5 +1,5 @@
-#include <mutex>
 /* #define DEBUGTRACE_ENABLED */
+#include <mutex>
 #include "debugtrace.hpp"
 #include "lasp_mathtypes.h"
 
@@ -177,23 +177,22 @@ public:
 
       inParams = std::make_unique<RtAudio::StreamParameters>();
 
-      // +1 to get the count.
-      inParams->nChannels = getHighestEnabledInChannel() + 1;
-      if (inParams->nChannels < 1) {
-        throw rte("Invalid input number of channels");
-      }
+      /// RtAudio lacks good bookkeeping when the first channel is not equal to
+      /// 0. For now, our fix is to shift out the channels we want, and let
+      /// RtAudio pass on all channels.
       inParams->firstChannel = 0;
+      inParams->nChannels = devinfo_gen.ninchannels;
       inParams->deviceId = devinfo._api_devindex;
 
     } else {
 
       outParams = std::make_unique<RtAudio::StreamParameters>();
 
-      outParams->nChannels = getHighestEnabledOutChannel() + 1;
-      if (outParams->nChannels < 1) {
-        throw rte("Invalid output number of channels");
-      }
+      /// RtAudio lacks good bookkeeping when the first channel is not equal to
+      /// 0. For now, our fix is to shift out the channels we want, and let
+      /// RtAudio pass on all channels.
       outParams->firstChannel = 0;
+      outParams->nChannels = devinfo_gen.noutchannels;
       outParams->deviceId = devinfo._api_devindex;
     }
 
@@ -355,15 +354,16 @@ public:
 
       const us ch_min = getLowestEnabledInChannel();
       const us ch_max = getHighestEnabledInChannel();
-      us i = 0;
+      assert(ch_min < ninchannels);
+      assert(ch_max < ninchannels);
+
+      /// Only pass on the pointers of the channels we want
       for (us ch = ch_min; ch <= ch_max; ch++) {
         if (inchannel_config.at(ch).enabled) {
           byte_t *ptr =
-              static_cast<byte_t *>(inputBuffer) + sw * i * nFramesPerBlock;
-          DEBUGTRACE_PRINT((us)ptr);
+              static_cast<byte_t *>(inputBuffer) + sw * ch * nFramesPerBlock;
           ptrs.push_back(ptr);
         }
-        i++;
       }
       DaqData d{nFramesPerBlock, neninchannels, dtype};
       d.copyInFromRaw(ptrs);
@@ -384,14 +384,14 @@ public:
 
       const us ch_min = getLowestEnabledOutChannel();
       const us ch_max = getHighestEnabledOutChannel();
-      us i = 0;
+      assert(ch_min < noutchannels);
+      assert(ch_max < noutchannels);
+      /// Only pass on the pointers of the channels we want
       for (us ch = ch_min; ch <= ch_max; ch++) {
         if (outchannel_config.at(ch).enabled) {
-
           ptrs.push_back(static_cast<byte_t *>(outputBuffer) +
-                         sw * i * nFramesPerBlock);
+                         sw * ch * nFramesPerBlock);
         }
-        i++;
       }
       DaqData d{nFramesPerBlock, nenoutchannels, dtype};