Add SubArray class

This allow to manipulate contiguous sub parts of arrays in the same way as arrays themselves

Note that for performances reasons, SubArray cannot be Array

src/utils/SubArray.hpp

+#ifndef SUB_ARRAY_HPP
+#define SUB_ARRAY_HPP
+
+#include <utils/Array.hpp>
+#include <utils/PugsAssert.hpp>
+#include <utils/PugsMacros.hpp>
+#include <utils/PugsUtils.hpp>
+
+#include <algorithm>
+
+template <typename DataType>
+class [[nodiscard]] SubArray
+{
+ public:
+  using data_type  = DataType;
+  using index_type = size_t;
+
+ private:
+  PUGS_RESTRICT DataType* const m_sub_values;
+  const size_t m_size;
+
+  // Allows const version to access our data
+  friend SubArray<std::add_const_t<DataType>>;
+
+ public:
+  PUGS_INLINE size_t size() const noexcept
+  {
+    return m_size;
+  }
+
+  PUGS_INLINE DataType& operator[](index_type i) const noexcept(NO_ASSERT)
+  {
+    Assert(i < m_size);
+    return m_sub_values[i];
+  }
+
+  PUGS_INLINE
+  void fill(const DataType& data) const
+  {
+    static_assert(not std::is_const<DataType>(), "Cannot modify SubArray of const");
+
+    // could consider to use std::fill
+    parallel_for(
+      this->size(), PUGS_LAMBDA(index_type i) { m_sub_values[i] = data; });
+  }
+
+  PUGS_INLINE
+  SubArray& operator=(const SubArray&) = delete;
+
+  PUGS_INLINE
+  SubArray& operator=(SubArray&&) = delete;
+
+  PUGS_INLINE
+  explicit SubArray(const Array<DataType>& array, size_t begin, size_t size)
+    : m_sub_values{&array[0] + begin}, m_size{size}
+  {
+    Assert(begin + size <= array.size(), "SubView is not contained in the source Array");
+  }
+
+  PUGS_INLINE
+  explicit SubArray(DataType* const raw_array, size_t begin, size_t size)
+    : m_sub_values{raw_array + begin}, m_size{size}
+  {}
+
+  PUGS_INLINE
+  SubArray() = delete;
+
+  PUGS_INLINE
+  SubArray(const SubArray&) = delete;
+
+  PUGS_INLINE
+  SubArray(SubArray &&) = delete;
+
+  PUGS_INLINE
+  ~SubArray() = default;
+};
+
+#endif   // SUB_ARRAY_HPP