Lay foundations for stream_reader class

1 files changed, 79 insertions, 0 deletions

diff --git a/include/io/stream_reader.h b/include/io/stream_reader.h
new file mode 100644
index 0000000000..142402a516
--- /dev/null
+++ b/include/io/stream_reader.h
@@ -0,0 +1,79 @@
+/*
+ * 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_READER_H_INCLUDED
+#define STREAM_READER_H_INCLUDED
+
+#include "endian_str.h"
+#include "tag.h"
+#include <iosfwd>
+#include <stdexcept>
+
+namespace nbt
+{
+namespace io
+{
+
+/**
+ * @brief Helper class for reading NBT tags from input streams
+ */
+class stream_reader
+{
+public:
+    ///Exception that gets thrown when reading is not successful
+    class input_error : public std::runtime_error
+    {
+        input_error(const std::string& what_arg):
+            std::runtime_error(what_arg) {}
+    };
+
+    /**
+     * @param is the stream to read from
+     * @param e the byte order of the source data. The Java edition
+     * of Minecraft uses Big Endian, the Pocket edition uses Little Endian
+     */
+    stream_reader(std::istream& is, endian::endian e = endian::big) noexcept;
+
+    ///Returns the stream
+    std::istream& get_istr() const;
+    ///Returns the byte order
+    endian::endian get_endian() const;
+
+    ///Reads a tag type from the stream
+    tag_type read_type(bool allow_end = false);
+    ///Reads a number from the stream
+    template<class T>
+    void read_num(T& x);
+    /**
+     * @brief Reads an NBT string from the stream
+     *
+     * An NBT string consists of two bytes indicating the length, followed by
+     * the characters encoded in modified UTF-8.
+     */
+    std::string read_string();
+
+private:
+    std::istream& is;
+    const endian::endian endian;
+};
+
+}
+}
+
+#endif // STREAM_READER_H_INCLUDED