Added writeFile() convenience function.

src/basicio.cpp

@@ -614,4 +614,13 @@ namespace Exiv2 {
         return buf;
     }
 
+    long writeFile(const DataBuf& buf, const std::string& path)
+    {
+        FileIo file(path);
+        if (file.open("wb") != 0) {
+            throw Error(10, path, "wb", strError());
+        }
+        return file.write(buf.pData_, buf.size_);
+    }
+
 }                                       // namespace Exiv2

src/basicio.hpp

@@ -683,6 +683,9 @@ namespace Exiv2 {
     //! Read file \em path into a DataBuf, which is returned.
     DataBuf readFile(const std::string& path);
 
+    //! Write DataBuf \em buf to file \em path. Return the number of bytes written.
+    long writeFile(const DataBuf& buf, const std::string& path);
+
 }                                       // namespace Exiv2
 
 #endif                                  // #ifndef BASICIO_HPP_