text: /*
  Copyright (c) 2015, Missing Box Studio
  All rights reserved.
  
  Redistribution and use in source and binary forms, with or without
  modification, are permitted provided that the following conditions are met:
  
  * Redistributions of source code must retain the above copyright notice, this
  list of conditions and the following disclaimer.
  
  * Redistributions in binary form must reproduce the above copyright notice,
  this list of conditions and the following disclaimer in the documentation
  and/or other materials provided with the distribution.
  
  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
  FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
  SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
  CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
  
  #pragma once
  
  #include <cstdint>
  
  #include "HeapCommon.h"
  
  /**
  *	Defines the header for a defraggable heap block.
  *
  *	We assume an alignment and size of 16 bytes so we can be globbed by an aligned SIMD load.
  */
  
  _declspec(align(16)) struct ListHeader
  {
  	/**
  	*	Constructs an empty, allocated block header.
  	*/
  	ListHeader();
  
  	/**
  	*	Constructs a block header from the given block data.
  	*
  	*	@param prev the index of the previous block in the heap
  	*	@param prev_free the index of the previous free block in the heap
  	*	@param next_free the index of the next free block in the heap
  	*	@param num_chunks the number of chunks on the block we represent
  	*	@param alloc the allocation state of the block
  	*/
  	ListHeader(IndexType prev, IndexType prev_free, IndexType next_free, IndexType num_chunks, AllocationState alloc);
  
  	/**< Index of the previous block for this header. */
  	IndexType _prev;
  
  	/**< Index of the previous free block. */
  	IndexType _prev_free;
  
  	/**< Index of the next free block. */
  	IndexType _next_free;
  
  	/**< Block allocation metadata. */
  	BlockMetadata _block_metadata;
  };
  
  static_assert(sizeof(ListHeader) == 16, "The block header needs to be 16 bytes in size.");