Index grow_by()

in dispenso/concurrent_object_arena.h [157:181]

• 20 lines of code
• 4 McCabe index (conditional complexity)

  Index grow_by(const Index delta) {
    Index newPos;
    Index oldPos = pos_.load(std::memory_order_relaxed);

    do {
      Index curSize = allocatedSize_.load(std::memory_order_acquire);

      if (oldPos + delta >= curSize) {
        const std::lock_guard<std::mutex> guard(resizeMutex_);
        curSize = allocatedSize_.load(std::memory_order_relaxed);
        while (oldPos + delta >= curSize) {
          allocateBuffer();
          allocatedSize_.store(curSize + kBufferSize, std::memory_order_release);
          curSize = curSize + kBufferSize;
        }
      }

      newPos = oldPos + delta;
    } while (!std::atomic_compare_exchange_weak_explicit(
        &pos_, &oldPos, newPos, std::memory_order_release, std::memory_order_relaxed));

    constructObjects(oldPos, oldPos + delta);

    return oldPos;
  }