2 files changed, 107 insertions, 0 deletions
diff --git a/src/util/ranges.hpp b/src/util/ranges.hpp
new file mode 100644
index 0000000..c47c7b5
--- /dev/null
+++ b/src/util/ranges.hpp
@@ -0,0 +1,47 @@
+#pragma once
+
+#include <concepts>
+#include <iterator>
+
+template <std::weakly_incrementable Value>
+class IotaViewIterator
+{
+public:
+	constexpr explicit IotaViewIterator(Value value) noexcept;
+
+	constexpr auto operator++() noexcept -> const IotaViewIterator &;
+	constexpr auto operator++(int) noexcept -> IotaViewIterator;
+
+	constexpr auto operator*() const noexcept -> Value;
+
+	constexpr auto operator==(const IotaViewIterator &rhs) const noexcept -> bool;
+	constexpr auto operator!=(const IotaViewIterator &rhs) const noexcept -> bool;
+
+private:
+	Value _value;
+};
+
+/**
+ * A range factory that generates a sequence of elements by repeatedly incrementing an
+ * initial value.
+ *
+ * This class was created because C++20 ranges is a complete shitshow in Clang.
+ * https://github.com/llvm/llvm-project/issues/52696
+ */
+template <std::weakly_incrementable Value, std::semiregular Bound>
+requires std::equality_comparable_with<Value, Bound> && std::copyable<Value>
+class IotaView
+{
+public:
+	constexpr IotaView(Value value, Bound bound) noexcept;
+
+	[[nodiscard]] constexpr auto begin() const noexcept -> IotaViewIterator<Value>;
+
+	[[nodiscard]] constexpr auto end() const noexcept -> IotaViewIterator<Value>;
+
+private:
+	Value _value;
+	Bound _bound;
+};
+
+#include "ranges_impl.hpp"
diff --git a/src/util/ranges_impl.hpp b/src/util/ranges_impl.hpp
new file mode 100644
index 0000000..b18a11c
--- /dev/null
+++ b/src/util/ranges_impl.hpp
@@ -0,0 +1,60 @@
+#pragma once
+
+#include "ranges.hpp"
+
+// NOLINTNEXTLINE(cppcoreguidelines-macro-usage)
+#define IOTA_VIEW_ITERATOR(return_type)                                                  \
+	template <std::weakly_incrementable Value>                                           \
+	constexpr return_type IotaViewIterator<Value>
+
+IOTA_VIEW_ITERATOR()::IotaViewIterator(Value value) noexcept : _value(value) {}
+
+IOTA_VIEW_ITERATOR(auto)::operator++() noexcept -> const IotaViewIterator &
+{
+	++_value;
+
+	return *this;
+}
+
+IOTA_VIEW_ITERATOR(auto)::operator++(int) noexcept -> IotaViewIterator
+{
+	auto copy = *this;
+
+	++(*this);
+
+	return copy;
+}
+
+IOTA_VIEW_ITERATOR(auto)::operator*() const noexcept -> Value
+{
+	return _value;
+}
+
+IOTA_VIEW_ITERATOR(auto)::operator==(const IotaViewIterator &rhs) const noexcept -> bool
+{
+	return _value == rhs._value;
+}
+
+IOTA_VIEW_ITERATOR(auto)::operator!=(const IotaViewIterator &rhs) const noexcept -> bool
+{
+	return !(*this == rhs);
+}
+
+// NOLINTNEXTLINE(cppcoreguidelines-macro-usage)
+#define IOTA_VIEW(return_type)                                                           \
+	template <std::weakly_incrementable Value, std::semiregular Bound>                   \
+	requires std::equality_comparable_with<Value, Bound> && std::copyable<Value>         \
+	constexpr return_type IotaView<Value, Bound>
+
+IOTA_VIEW()::IotaView(Value value, Bound bound) noexcept : _value(value), _bound(bound) {}
+
+IOTA_VIEW(auto)::begin() const noexcept -> IotaViewIterator<Value>
+{
+	return IotaViewIterator(_value);
+}
+
+IOTA_VIEW(auto)::end() const noexcept -> IotaViewIterator<Value>
+{
+	return IotaViewIterator(_bound);
+}
+