GH-1047 parse world files and integrate MCEdit with world page

depends/libnbtplusplus/include/io/stream_reader.h

@@ -0,0 +1,138 @@
+/*
+ * 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 "tag_compound.h"
+#include <iosfwd>
+#include <memory>
+#include <stdexcept>
+#include <utility>
+
+#include "nbt++_export.h"
+
+namespace nbt
+{
+namespace io
+{
+
+///Exception that gets thrown when reading is not successful
+class NBT___EXPORT input_error : public std::runtime_error
+{
+    using std::runtime_error::runtime_error;
+};
+
+/**
+* @brief Reads a named tag from the stream, making sure that it is a compound
+* @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
+* @throw input_error on failure, or if the tag in the stream is not a compound
+*/
+NBT___EXPORT std::pair<std::string, std::unique_ptr<tag_compound>> read_compound(std::istream& is, endian::endian e = endian::big);
+
+/**
+* @brief Reads a named tag from the stream
+* @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
+* @throw input_error on failure
+*/
+NBT___EXPORT std::pair<std::string, std::unique_ptr<tag>> read_tag(std::istream& is, endian::endian e = endian::big);
+
+/**
+ * @brief Helper class for reading NBT tags from input streams
+ *
+ * Can be reused to read multiple tags
+ */
+class NBT___EXPORT stream_reader
+{
+public:
+    /**
+     * @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
+     */
+    explicit 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;
+
+    /**
+     * @brief Reads a named tag from the stream, making sure that it is a compound
+     * @throw input_error on failure, or if the tag in the stream is not a compound
+     */
+    std::pair<std::string, std::unique_ptr<tag_compound>> read_compound();
+
+    /**
+     * @brief Reads a named tag from the stream
+     * @throw input_error on failure
+     */
+    std::pair<std::string, std::unique_ptr<tag>> read_tag();
+
+    /**
+     * @brief Reads a tag of the given type without name from the stream
+     * @throw input_error on failure
+     */
+    std::unique_ptr<tag> read_payload(tag_type type);
+
+    /**
+     * @brief Reads a tag type from the stream
+     * @param allow_end whether to consider tag_type::End valid
+     * @throw input_error on failure
+     */
+    tag_type read_type(bool allow_end = false);
+
+    /**
+     * @brief Reads a binary number from the stream
+     *
+     * On failure, will set the failbit on 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.
+     * @throw input_error on failure
+     */
+    std::string read_string();
+
+private:
+    std::istream& is;
+    const endian::endian endian;
+};
+
+template<class T>
+void stream_reader::read_num(T& x)
+{
+    endian::read(is, x, endian);
+}
+
+}
+}
+
+#endif // STREAM_READER_H_INCLUDED