commit 1.2

source/io.ixx

@@ -0,0 +1,31 @@
+export module io;
+
+import std;
+
+namespace brc {
+
+export [[nodiscard]] std::string read_file(const std::filesystem::path& path);
+
+export class mapped_file {
+private:
+	int fd;
+	void* data = nullptr;
+	std::size_t length = 0;
+
+public:
+	explicit mapped_file(const std::filesystem::path& path);
+
+	mapped_file(const mapped_file&) = delete;
+	mapped_file& operator=(const mapped_file&) = delete;
+
+	mapped_file(mapped_file&& rhs) noexcept;
+	mapped_file& operator=(mapped_file&& rhs) noexcept;
+
+	~mapped_file();
+
+	operator std::string_view() const noexcept;
+
+	[[nodiscard]] std::size_t size() const noexcept;
+};
+
+}  // namespace brc