RmlUi/Source/Core/Layout/LayoutPools.cpp

#include "LayoutPools.h"
#include "../../../Include/RmlUi/Core/Element.h"
#include "../ControlledLifetimeResource.h"
#include "../Pool.h"
#include "BlockContainer.h"
#include "FloatedBoxSpace.h"
#include "FormattingContext.h"
#include "InlineBox.h"
#include "InlineContainer.h"
#include "LineBox.h"
#include "ReplacedFormattingContext.h"
#include <algorithm>
#include <cstddef>

namespace Rml {

template <size_t Size>
struct LayoutChunk {
	alignas(std::max_align_t) byte buffer[Size];
};

static constexpr size_t ChunkSizeBig = std::max({sizeof(BlockContainer)});
static constexpr size_t ChunkSizeMedium =
	std::max({sizeof(InlineContainer), sizeof(InlineBox), sizeof(RootBox), sizeof(FlexContainer), sizeof(TableWrapper)});
static constexpr size_t ChunkSizeSmall =
	std::max({sizeof(ReplacedBox), sizeof(InlineLevelBox_Text), sizeof(InlineLevelBox_Atomic), sizeof(LineBox), sizeof(FloatedBoxSpace)});

struct LayoutPoolsData {
	Pool<LayoutChunk<ChunkSizeBig>> layout_chunk_pool_big{50, true};
	Pool<LayoutChunk<ChunkSizeMedium>> layout_chunk_pool_medium{50, true};
	Pool<LayoutChunk<ChunkSizeSmall>> layout_chunk_pool_small{50, true};
};

static ControlledLifetimeResource<LayoutPoolsData> layout_pools_data;

void LayoutPools::Initialize()
{
	layout_pools_data.Initialize();
}
void LayoutPools::Shutdown()
{
	layout_pools_data.Shutdown();
}

void* LayoutPools::AllocateLayoutChunk(size_t size)
{
	static_assert(ChunkSizeBig > ChunkSizeMedium && ChunkSizeMedium > ChunkSizeSmall, "The following assumes a strict ordering of the chunk sizes.");

	// Note: If any change is made here, make sure a corresponding change is applied to the deallocation procedure below.
	if (size <= ChunkSizeSmall)
		return layout_pools_data->layout_chunk_pool_small.AllocateAndConstruct();
	else if (size <= ChunkSizeMedium)
		return layout_pools_data->layout_chunk_pool_medium.AllocateAndConstruct();
	else if (size <= ChunkSizeBig)
		return layout_pools_data->layout_chunk_pool_big.AllocateAndConstruct();

	RMLUI_ERROR;
	return nullptr;
}

void LayoutPools::DeallocateLayoutChunk(void* chunk, size_t size)
{
	// Note: If any change is made here, make sure a corresponding change is applied to the allocation procedure above.
	if (size <= ChunkSizeSmall)
		layout_pools_data->layout_chunk_pool_small.DestroyAndDeallocate((LayoutChunk<ChunkSizeSmall>*)chunk);
	else if (size <= ChunkSizeMedium)
		layout_pools_data->layout_chunk_pool_medium.DestroyAndDeallocate((LayoutChunk<ChunkSizeMedium>*)chunk);
	else if (size <= ChunkSizeBig)
		layout_pools_data->layout_chunk_pool_big.DestroyAndDeallocate((LayoutChunk<ChunkSizeBig>*)chunk);
	else
	{
		RMLUI_ERROR;
	}
}

} // namespace Rml