diff -r 489e52138771 -r c87e9c84f7aa src/StringDataTypeReader.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/StringDataTypeReader.h	Sun Jul 15 00:15:09 2018 +0200
@@ -0,0 +1,52 @@
+#pragma once
+
+#include <string>
+#include <sstream>
+#include <iostream>
+#include <vector>
+#include <locale>
+#include <codecvt>
+
+#include "../include/typedefs.h"
+#include "../include/DataTypeReader.h"
+#include "../include/DataTypeReader.h"
+#include "format.h"
+
+namespace relpipe {
+namespace reader {
+
+/**
+ * The prototype does not recognize any encoding,
+ * it just works with c++ strings in encoding default to given platform. 
+ * In the real implementation of relational pipes, there will be DataTypes for particular encodings.
+ */
+class StringDataTypeReader : public DataTypeReader<string_t> {
+private:
+	IntegerDataTypeReader integerType;
+	std::wstring_convert<std::codecvt_utf8<wchar_t>> convertor; // TODO: support also other encodings.
+public:
+
+	StringDataTypeReader() : DataTypeReader<string_t>(DATA_TYPE_ID_STRING, DATA_TYPE_CODE_STRING) {
+	}
+
+	string_t readValue(std::istream &input) override {
+		integer_t length = integerType.readValue(input);
+		// TODO: check maximum length of single field
+		// if (length > 4000) throw RelpipeException("data too long", EXIT_CODE_DATA_ERROR);
+		std::vector<char> buf(length);
+		input.read(buf.data(), length);
+		if (input.good()) {
+			return convertor.from_bytes(std::string(buf.data(), length));
+		} else {
+			throw RelpipeReaderException(L"Error while reading string from the stream.");
+		}
+	}
+
+	string_t toString(const string_t &value) override {
+		return value;
+	}
+
+};
+
+}
+}
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