Lay foundations for stream writing

1 files changed, 90 insertions, 0 deletions

diff --git a/include/io/stream_writer.h b/include/io/stream_writer.h
new file mode 100644
index 0000000000..ea3dcd1c58
--- /dev/null
+++ b/include/io/stream_writer.h
@@ -0,0 +1,90 @@
+/*
+ * libnbt++ - A library for the Minecraft Named Binary Tag format.
+ * Copyright (C) 2013, 2015  ljfa-ag
+ *
+ * This file is part of libnbt++.
+ *
+ * libnbt++ is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * libnbt++ is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with libnbt++.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#ifndef STREAM_WRITER_H_INCLUDED
+#define STREAM_WRITER_H_INCLUDED
+
+#include "tag.h"
+#include "endian_str.h"
+#include <iosfwd>
+#include <stdexcept>
+
+namespace nbt
+{
+namespace io
+{
+
+///Exception that gets thrown when writing is not successful
+class output_error : public std::runtime_error
+{
+    using std::runtime_error::runtime_error;
+};
+
+/**
+ * @brief Helper class for writing NBT tags to output streams
+ */
+class stream_writer
+{
+public:
+    /**
+     * @param os the stream to write to
+     * @param e the byte order of the written data. The Java edition
+     * of Minecraft uses Big Endian, the Pocket edition uses Little Endian
+     */
+    explicit stream_writer(std::ostream& os, endian::endian e = endian::big) noexcept;
+
+    ///Returns the stream
+    std::ostream& get_ostr() const;
+    ///Returns the byte order
+    endian::endian get_endian() const;
+
+    /**
+     * @brief Writes a tag type to the stream
+     */
+    void write_type(tag_type tt);
+
+    /**
+     * @brief Writes a binary number to the stream
+     */
+    template<class T>
+    void write_num(T x);
+
+    /**
+     * @brief Writes an NBT string to the stream
+     *
+     * An NBT string consists of two bytes indicating the length, followed by
+     * the characters encoded in modified UTF-8.
+     */
+    void write_string(const std::string& str);
+
+private:
+    std::ostream& os;
+    const endian::endian endian;
+};
+
+template<class T>
+void stream_writer::write_num(T x)
+{
+    endian::write(os, x, endian);
+}
+
+}
+}
+
+#endif // STREAM_WRITER_H_INCLUDED