+ // pointer to the value at the front of the queue (for use in-place) or
+ // nullptr if empty.
+ T* frontPtr() {
+ auto const currentRead = readIndex_.load(std::memory_order_relaxed);
+ if (currentRead == writeIndex_.load(std::memory_order_acquire)) {
+ // queue is empty
+ return nullptr;
+ }
+ return &records_[currentRead];
+ }
+
+ // queue must not be empty
+ void popFront() {
+ auto const currentRead = readIndex_.load(std::memory_order_relaxed);
+ assert(currentRead != writeIndex_.load(std::memory_order_acquire));
+
+ auto nextRecord = currentRead + 1;
+ if (nextRecord == size_) {
+ nextRecord = 0;
+ }
+ records_[currentRead].~T();
+ readIndex_.store(nextRecord, std::memory_order_release);
+ }
+
+ bool isEmpty() const {
+ return readIndex_.load(std::memory_order_acquire) ==
+ writeIndex_.load(std::memory_order_acquire);
+ }
+