iostreams non_blocking_adapter read bug

[Mario Suvajac <msuvajac@…>]

When reading from device resulting amount of read bytes is ignored.

line 31. of boost/iostreams/detail/adapter/non_blocking_adapter.hpp

     explicit non_blocking_adapter(Device& dev) : device_(dev) { }
     std::streamsize read(char_type* s, std::streamsize n)
     { 
         std::streamsize result = 0;
         while (result < n) {
-            std::streamsize amt = iostreams::read(device_, s, n);
+            std::streamsize amt = iostreams::read(device_, s, n - result);
             if (amt == -1)
                 break;
             result += amt;
         }
         return result != 0 ? result : -1;
     }

[Mario Suvajac <msuvajac@…>]

actually, it should be:

-            std::streamsize amt = iostreams::read(device_, s, n);
+            std::streamsize amt = iostreams::read(device_, s + result, n - result);

[msuvajac@…]

Buffer overwrite test case.

[msuvajac@…]

Patch

[msuvajac@…]

I've added a test case for this bug and a patch.

Also another issue for this adapter is if a device returns 0 as the amount read/written, that would cause a deadlock - endless loop.