PublicBin/infinite_sparce_cube.hpp

#pragma once
#include <vector>
#include <array>

template<typename T, size_t chunk_size = 16>
struct cube {
	struct chunk_elem_t {
		size_t coord;
		T elem;
	};
	
	struct chunk_t {
		std::array<std::array<std::vector<chunk_elem_t>, chunk_size>, chunk_size> data;
	};
	
	struct row_t {
		size_t coord;
		std::shared_ptr<chunk_t> value;
	};
	
	struct column_t {
		size_t coord;
		std::vector<row_t> value;
	};
	
	std::vector<column_t> chunks;
	
	std::optional<T> at(size_t x, size_t y, size_t z) {
		auto column = std::ranges::find_if(chunks, [&](const column_t& col) {
			return col.coord == y/chunk_size;
		});
		if(column == chunks.end()) return std::nullopt;
		auto row = std::ranges::find_if(column->value, [&](const row_t& row) {
			return row.coord == x/chunk_size;
		});
		if(column->value.end() == row) return std::nullopt;
		auto& chunk_segment = row->value->data.at(x%chunk_size).at(y%chunk_size);
		auto position = std::ranges::find_if(chunk_segment, [&](const chunk_elem_t& item) {
			return item.coord == z;
		});
		if(position == chunk_segment.end())  return std::nullopt;
		return position->elem;
	}
	
	void set(size_t x, size_t y, size_t z, T&& value) {
		auto column = std::ranges::find_if(chunks, [&](const column_t& col) {
			return col.coord == y/chunk_size;
		});
		if(column == chunks.end()) {
			auto chunk = std::make_shared<chunk_t>();
			chunks.push_back(column_t{
				.coord = y / chunk_size,
				.value = {
					row_t{
						.coord = x/chunk_size,
						.value = chunk 
					}
				}
			});
			chunk->data.at(x%chunk_size).at(y%chunk_size).push_back(chunk_elem_t{
				.coord = z,
				.elem = std::move(value)
			});
			return;
		}
		auto row = std::ranges::find_if(column->value, [&](const row_t& row) {
			return row.coord == x/chunk_size;
		});
		if(column->value.end() == row)  {
			auto chunk = std::make_shared<chunk_t>();
			column->value.push_back(
				row_t{
					.coord = x/chunk_size,
					.value = chunk
				}
			);
			chunk->data.at(x%chunk_size).at(y%chunk_size).push_back(chunk_elem_t{
				.coord = z,
				.elem = std::move(value)
			});
			return;
		}
		auto& chunk_segment = row->value->data.at(x%chunk_size).at(y%chunk_size);
		auto position = std::ranges::find_if(chunk_segment, [&](const chunk_elem_t& item) {
			return item.coord == z;
		});
		if(position == chunk_segment.end()) {
			chunk_segment.push_back(chunk_elem_t{
				.coord = z,
				.elem = std::move(value)
			});
			return;
		}
		position->elem = std::move(value);
	}
};