3 files changed, 116 insertions, 11 deletions
diff --git a/include/io/izlibstream.h b/include/io/izlibstream.h
new file mode 100644
index 0000000000..edf632eddf
--- /dev/null
+++ b/include/io/izlibstream.h
@@ -0,0 +1,96 @@
+/*
+ * 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 IZLIBSTREAM_H_INCLUDED
+#define IZLIBSTREAM_H_INCLUDED
+
+#include <istream>
+#include <vector>
+#include <zlib.h>
+
+namespace zlib
+{
+
+/**
+ * @brief Stream buffer used by zlib::izlibstream
+ * @sa izlibstream
+ */
+class inflate_streambuf : public std::streambuf
+{
+public:
+    /**
+     * @param input the istream to wrap
+     * @param bufsize the size of the internal buffers
+     * @param window_bits the base two logarithm of the maximum window size that
+     * zlib will use. This parameter also determines which type of input to expect.
+     * The default argument will autodetect between zlib and gzip data.
+     * Refer to the zlib documentation of inflateInit2 for more details.
+     *
+     * @throw zlib_error if zlib encounters a problem during initialization
+     */
+    explicit inflate_streambuf(std::istream& input, size_t bufsize = 32768, int window_bits = 32 + 15);
+    ~inflate_streambuf() noexcept;
+
+    //No copying or moving
+    inflate_streambuf(const inflate_streambuf&) = delete;
+    inflate_streambuf& operator=(const inflate_streambuf&) = delete;
+
+    ///@return the wrapped istream
+    std::istream& get_istr() const { return is; }
+
+private:
+    std::istream& is;
+    std::vector<char> in;
+    std::vector<char> out;
+    z_stream zstr;
+    bool stream_end;
+
+    int_type underflow() override;
+};
+
+/**
+ * @brief An istream adapter that decompresses data using zlib
+ *
+ * This istream wraps another istream. The izlibstream will read compressed
+ * data from the wrapped istream and inflate (decompress) it with zlib.
+ *
+ * @sa inflate_streambuf
+ */
+class izlibstream : public std::istream
+{
+public:
+    /**
+     * @param input the istream to wrap
+     * @param bufsize the size of the internal buffers
+     */
+    explicit izlibstream(std::istream& input, size_t bufsize = 32768):
+        buf(input, bufsize)
+    {
+        init(&buf);
+    }
+    ///@return the wrapped istream
+    std::istream& get_istr() const { return buf.get_istr(); }
+
+private:
+    inflate_streambuf buf;
+};
+
+}
+
+#endif // IZLIBSTREAM_H_INCLUDED
diff --git a/include/io/ozlibstream.h b/include/io/ozlibstream.h
index c427281763..6ebd3c0dd0 100644
--- a/include/io/ozlibstream.h
+++ b/include/io/ozlibstream.h
@@ -20,6 +20,7 @@
 #ifndef OZLIBSTREAM_H_INCLUDED
 #define OZLIBSTREAM_H_INCLUDED
 
+#include "io/zlib_error.h"
 #include <ostream>
 #include <vector>
 #include <zlib.h>
@@ -27,17 +28,6 @@
 namespace zlib
 {
 
-///Exception thrown in case zlib encounters a problem
-class zlib_error : public std::runtime_error
-{
-public:
-    const int errcode;
-
-    explicit zlib_error(const char* what_arg, int errcode = Z_ERRNO):
-        std::runtime_error(what_arg), errcode(errcode)
-    {}
-};
-
 /**
  * @brief Stream buffer used by zlib::ozlibstream
  * @see ozlibstream
diff --git a/include/io/zlib_error.h b/include/io/zlib_error.h
new file mode 100644
index 0000000000..ce375a6ccd
--- /dev/null
+++ b/include/io/zlib_error.h
@@ -0,0 +1,19 @@
+#ifndef ZLIB_ERROR_H_INCLUDED
+#define ZLIB_ERROR_H_INCLUDED
+
+#include <stdexcept>
+#include <zlib.h>
+
+///Exception thrown in case zlib encounters a problem
+class zlib_error : public std::runtime_error
+{
+public:
+    const int errcode;
+
+    explicit zlib_error(const char* msg, int errcode):
+        std::runtime_error(std::string(zError(errcode)) + ": " + msg),
+        errcode(errcode)
+    {}
+};
+
+#endif // ZLIB_ERROR_H_INCLUDED