From 649c051b61e3e429fc6b0e4cabc0c393ce9fd861 Mon Sep 17 00:00:00 2001
From: lisyarus <lisyarus@gmail.com>
Date: Fri, 5 Aug 2022 15:54:58 +0300
Subject: [PATCH] Add auto-expanding in all directions util::spatial_array

---
 .../include/psemek/util/spatial_array.hpp     | 174 ++++++++++++++++++
 1 file changed, 174 insertions(+)
 create mode 100644 libs/util/include/psemek/util/spatial_array.hpp

diff --git a/libs/util/include/psemek/util/spatial_array.hpp b/libs/util/include/psemek/util/spatial_array.hpp
new file mode 100644
index 00000000..c0b60c1a
--- /dev/null
+++ b/libs/util/include/psemek/util/spatial_array.hpp
@@ -0,0 +1,174 @@
+#pragma once
+
+#include <psemek/util/array.hpp>
+
+#include <stdexcept>
+
+namespace psemek::util
+{
+
+	template <typename T, std::size_t N, typename Index = std::int32_t>
+	struct spatial_array
+	{
+		spatial_array();
+
+		using index_type = Index;
+
+		template <typename ... Ix>
+		T & get(Ix ... index);
+
+		template <typename ... Ix>
+		T * get_if(Ix ... index);
+
+		template <typename ... Ix>
+		T const * get_if(Ix ... index) const;
+
+		template <typename ... Ix>
+		T const & at(Ix ... index) const;
+
+		template <typename ... Ix>
+		bool contains(Ix ... index) const;
+
+		template <typename ... Ix>
+		void expand(Ix ... index);
+
+		void clear();
+
+	private:
+		Index origin_[N];
+		array<T, N> array_;
+	};
+
+	template <typename T, std::size_t N, typename Index>
+	spatial_array<T, N, Index>::spatial_array()
+	{
+		for (std::size_t i = 0; i < N; ++i)
+			origin_[i] = 0;
+	}
+
+	template <typename T, std::size_t N, typename Index>
+	template <typename ... Ix>
+	T & spatial_array<T, N, Index>::get(Ix ... index)
+	{
+		if (!contains(index...))
+			expand(index...);
+
+		Index ix[N] {index...};
+		for (std::size_t i = 0; i < N; ++i)
+			ix[i] -= origin_[i];
+		return array_(ix);
+	}
+
+	template <typename T, std::size_t N, typename Index>
+	template <typename ... Ix>
+	T * spatial_array<T, N, Index>::get_if(Ix ... index)
+	{
+		if (!contains(index...))
+			return nullptr;
+
+		Index ix[N] {index...};
+		for (std::size_t i = 0; i < N; ++i)
+			ix[i] -= origin_[i];
+		return &array_(ix);
+	}
+
+	template <typename T, std::size_t N, typename Index>
+	template <typename ... Ix>
+	T const * spatial_array<T, N, Index>::get_if(Ix ... index) const
+	{
+		if (!contains(index...))
+			return nullptr;
+
+		Index ix[N] {index...};
+		for (std::size_t i = 0; i < N; ++i)
+			ix[i] -= origin_[i];
+		return &array_(ix);
+	}
+
+	template <typename T, std::size_t N, typename Index>
+	template <typename ... Ix>
+	T const & spatial_array<T, N, Index>::at(Ix ... index) const
+	{
+		auto const size = array_.dims();
+		Index ix[N] {index...};
+		for (std::size_t i = 0; i < N; ++i)
+		{
+			if (ix[i] < origin_[i] || ix[i] >= origin_[i] + static_cast<Index>(size[i]))
+				throw std::runtime_error("element out of range");
+			ix[i] -= origin_[i];
+		}
+		return array_(ix);
+	}
+
+	template <typename T, std::size_t N, typename Index>
+	template <typename ... Ix>
+	bool spatial_array<T, N, Index>::contains(Ix ... index) const
+	{
+		auto const size = array_.dims();
+		Index ix[N] {index...};
+		for (std::size_t i = 0; i < N; ++i)
+			if (ix[i] < origin_[i] || ix[i] >= origin_[i] + static_cast<Index>(size[i]))
+				return false;
+		return true;
+	}
+
+	template <typename T, std::size_t N, typename Index>
+	template <typename ... Ix>
+	void spatial_array<T, N, Index>::expand(Ix ... index)
+	{
+		Index ix[N] {index...};
+
+		if (array_.empty())
+		{
+			std::array<std::size_t, N> size;
+
+			for (std::size_t i = 0; i < N; ++i)
+			{
+				origin_[i] = ix[i];
+				size[i] = 1;
+			}
+
+			array_.resize(size);
+			return;
+		}
+
+		Index new_origin[N];
+		std::array<std::size_t, N> new_size = array_.dims();
+
+		for (std::size_t i = 0; i < N; ++i)
+			new_origin[i] = origin_[i];
+
+		for (std::size_t i = 0; i < N; ++i)
+		{
+			while (ix[i] >= new_origin[i] + static_cast<Index>(new_size[i]))
+				new_size[i] += new_size[i];
+
+			while (ix[i] < new_origin[i])
+			{
+				new_origin[i] -= static_cast<Index>(new_size[i]);
+				new_size[i] += new_size[i];
+			}
+		}
+
+		array<T, N> new_array(new_size);
+		for (auto idx : array_.indices())
+		{
+			std::array<std::size_t, N> new_idx;
+			for (std::size_t i = 0; i < N; ++i)
+				new_idx[i] = static_cast<Index>(idx[i]) + origin_[i] - new_origin[i];
+			new_array(new_idx) = std::move(array_(idx));
+		}
+
+		array_ = std::move(new_array);
+
+		for (std::size_t i = 0; i < N; ++i)
+			origin_[i] = new_origin[i];
+	}
+
+	template <typename T, std::size_t N, typename Index>
+	void spatial_array<T, N, Index>::clear()
+	{
+		array_.clear();
+	}
+
+}