diff --git a/libs/io/include/psemek/io/file_stream.hpp b/libs/io/include/psemek/io/file_stream.hpp
index 2bce09a7..b71b5beb 100644
--- a/libs/io/include/psemek/io/file_stream.hpp
+++ b/libs/io/include/psemek/io/file_stream.hpp
@@ -40,6 +40,8 @@ namespace psemek::io
 
 		std::size_t read(char * p, std::size_t size) override;
 
+		bool finished() const override;
+
 		~file_istream() override
 		{
 			reset();
diff --git a/libs/io/include/psemek/io/memory_stream.hpp b/libs/io/include/psemek/io/memory_stream.hpp
index e90102cc..988d0ceb 100644
--- a/libs/io/include/psemek/io/memory_stream.hpp
+++ b/libs/io/include/psemek/io/memory_stream.hpp
@@ -55,6 +55,11 @@ namespace psemek::io
 
 		std::size_t read(char * p, std::size_t size) override;
 
+		bool finished() const override
+		{
+			return begin_ == end_;
+		}
+
 		void advance(std::size_t n)
 		{
 			if (end_ - begin_ < n)
diff --git a/libs/io/include/psemek/io/stream.hpp b/libs/io/include/psemek/io/stream.hpp
index 3c838a0d..88f07fcf 100644
--- a/libs/io/include/psemek/io/stream.hpp
+++ b/libs/io/include/psemek/io/stream.hpp
@@ -13,6 +13,7 @@ namespace psemek::io
 	{
 		virtual std::size_t read(char * p, std::size_t size) = 0;
 		virtual std::size_t read_all(char * p, std::size_t size);
+		virtual bool finished() const = 0;
 
 		virtual ~istream() {}
 	};
diff --git a/libs/io/source/file_stream.cpp b/libs/io/source/file_stream.cpp
index 0755c1ae..7c1cc481 100644
--- a/libs/io/source/file_stream.cpp
+++ b/libs/io/source/file_stream.cpp
@@ -37,6 +37,12 @@ namespace psemek::io
 		return std::fread(p, 1, size, file_);
 	}
 
+	bool file_istream::finished() const
+	{
+		if (!file_) throw null_istream{};
+		return std::feof(file_) != 0;
+	}
+
 	static char const * fopen_write_mode(unsigned flags)
 	{
 		switch (flags)