Function enqueue_bulk

source/util/concurrentqueue.h:2626–2764

#endif
		template<AllocationMode allocMode, typename It>
		bool enqueue_bulk(It itemFirst, size_t count)
		{
			// First, we need to make sure we have enough room to enqueue all of the elements;
			// this means pre-allocating blocks and putting them in the block index (but only if
			// all the allocations succeeded).
			
			// Note that the tailBlock we start off with may not be owned by us any more;
			// this happens if it was filled up exactly to the top (setting tailIndex to
			// the first index of the next block which is not yet allocated), then dequeued
			// completely (putting it on the free list) before we enqueue again.
			
			index_t startTailIndex = this->tailIndex.load(std::memory_order_relaxed);
			auto startBlock = this->tailBlock;
			Block* firstAllocatedBlock = nullptr;
			auto endBlock = this->tailBlock;
			
			// Figure out how many blocks we'll need to allocate, and do so
			size_t blockBaseDiff = ((startTailIndex + count - 1) & ~static_cast<index_t>(BLOCK_SIZE - 1)) - ((startTailIndex - 1) & ~static_cast<index_t>(BLOCK_SIZE - 1));
			index_t currentTailIndex = (startTailIndex - 1) & ~static_cast<index_t>(BLOCK_SIZE - 1);
			if (blockBaseDiff > 0) {
#ifdef MCDBGQ_NOLOCKFREE_IMPLICITPRODBLOCKINDEX
				debug::DebugLock lock(mutex);
#endif
				do {
					blockBaseDiff -= static_cast<index_t>(BLOCK_SIZE);
					currentTailIndex += static_cast<index_t>(BLOCK_SIZE);
					
					// Find out where we'll be inserting this block in the block index
					BlockIndexEntry* idxEntry = nullptr;  // initialization here unnecessary but compiler can't always tell
					Block* newBlock;
					bool indexInserted = false;
					auto head = this->headIndex.load(std::memory_order_relaxed);
					assert(!details::circular_less_than<index_t>(currentTailIndex, head));
					bool full = !details::circular_less_than<index_t>(head, currentTailIndex + BLOCK_SIZE) || (MAX_SUBQUEUE_SIZE != details::const_numeric_max<size_t>::value && (MAX_SUBQUEUE_SIZE == 0 || MAX_SUBQUEUE_SIZE - BLOCK_SIZE < currentTailIndex - head));

					if (full || !(indexInserted = insert_block_index_entry<allocMode>(idxEntry, currentTailIndex)) || (newBlock = this->parent->ConcurrentQueue::template requisition_block<allocMode>()) == nullptr) {
						// Index allocation or block allocation failed; revert any other allocations
						// and index insertions done so far for this operation
						if (indexInserted) {
							rewind_block_index_tail();
							idxEntry->value.store(nullptr, std::memory_order_relaxed);
						}
						currentTailIndex = (startTailIndex - 1) & ~static_cast<index_t>(BLOCK_SIZE - 1);
						for (auto block = firstAllocatedBlock; block != nullptr; block = block->next) {
							currentTailIndex += static_cast<index_t>(BLOCK_SIZE);
							idxEntry = get_block_index_entry_for_index(currentTailIndex);
							idxEntry->value.store(nullptr, std::memory_order_relaxed);
							rewind_block_index_tail();
						}
						this->parent->add_blocks_to_free_list(firstAllocatedBlock);
						this->tailBlock = startBlock;
						
						return false;
					}
					
#ifdef MCDBGQ_TRACKMEM
					newBlock->owner = this;
#endif