Add SpMcRingBuffer to base class StimulusBuffer

This will hopefully genericise the interface for Stimbuffs.

include/user/spMcRingBuffer.h

@@ -2,6 +2,7 @@
 #define _SP_MC_RING_BUFFER_H
 
 #include <vector>
+#include <memory>
 #include <cstddef>
 #include <stdexcept>
 #include <algorithm>
@@ -44,8 +45,8 @@ public:
 	 * locks array.
 	 */
 	explicit SpMcRingBuffer(
-		const InputEngineConstraints& constraints_,
-		size_t nSlots_)
+		size_t nSlots_,
+		const InputEngineConstraints& constraints_)
 	: nSlots(nSlots_), strideNBytes(0), bufferNBytes(0),
 	  constraints(constraints_)
 	{
@@ -59,7 +60,8 @@ public:
 		// Allocate data buffer: bufferNBytes (aligned up to alignment)
 		data.resize(bufferNBytes);
 		// Initialize sequence locks array: one lock per slot
-		sequenceLocks.resize(nSlots);
+		// Use unique_ptr array since SequenceLock is not copyable or movable
+		sequenceLocks = std::make_unique<SequenceLock[]>(nSlots);
 	}
 
 	~SpMcRingBuffer() = default;
@@ -121,7 +123,8 @@ private:
 	std::vector<uint8_t> data;
 
 	// Sequence locks array: one lock per slot
-	std::vector<SequenceLock> sequenceLocks;
+	// Use unique_ptr array since SequenceLock is not copyable or movable
+	std::unique_ptr<SequenceLock[]> sequenceLocks;
 
 public:
 	// Layout/invariants