Merge pull request #61 from mateidavid/gcc4_8

allow backward compatibility with gcc 4.8

README.org

@@ -96,7 +96,7 @@ Method 3. Add path containing 'zstr.hpp' to your target's include directories
 
 **** Requisites
 
-If you use GCC, you need to deploy at least version 5.1.
+If you use GCC and want to use the `fs.open()` function, you need to deploy at least GCC version 5.1.
 
 **** License
 

src/zstr.hpp

@@ -16,6 +16,14 @@
 #include <iostream>
 #include "strict_fstream.hpp"
 
+#if defined(__GNUC__) && !defined(__clang__)
+#if (__GNUC__ > 5) || (__GNUC__ == 5 && __GNUC_MINOR__>0)
+#define CAN_MOVE_IOSTREAM
+#endif
+#else
+#define CAN_MOVE_IOSTREAM
+#endif
+
 namespace zstr
 {
 
@@ -423,10 +431,12 @@ class ifstream
     void close() {
         _fs.close();
     }
+    #ifdef CAN_MOVE_IOSTREAM
     void open(const std::string filename, std::ios_base::openmode mode = std::ios_base::in) {
         _fs.open(filename, mode);
         std::istream::operator=(std::istream(new istreambuf(_fs.rdbuf())));
     }
+    #endif
     bool is_open() const {
         return _fs.is_open();
     }
@@ -460,11 +470,13 @@ class ofstream
         std::ostream::flush();
         _fs.close();
     }
+    #ifdef CAN_MOVE_IOSTREAM
     void open(const std::string filename, std::ios_base::openmode mode = std::ios_base::out, int level = Z_DEFAULT_COMPRESSION) {
         flush();
         _fs.open(filename, mode | std::ios_base::binary);
         std::ostream::operator=(std::ostream(new ostreambuf(_fs.rdbuf(), default_buff_size, level)));
     }
+    #endif
     bool is_open() const {
         return _fs.is_open();
     }