More fixes to I/O unification stuff

Author: lpereira

src/lib/lwan-io-wrappers.c

@@ -78,11 +78,11 @@ ssize_t lwan_writev_fd(struct lwan_request *request,
                 curr_iov++;
             }
 
-            iov[curr_iov].iov_base = (char *)iov[curr_iov].iov_base + written;
-            iov[curr_iov].iov_len -= (size_t)written;
-
             if (curr_iov == iov_count)
                 return total_written;
+
+            iov[curr_iov].iov_base = (char *)iov[curr_iov].iov_base + written;
+            iov[curr_iov].iov_len -= (size_t)written;
         }
 
         lwan_request_await_read(request, fd);
@@ -134,12 +134,12 @@ ssize_t lwan_readv_fd(struct lwan_request *request,
                 curr_iov++;
             }
 
+            if (curr_iov == iov_count)
+                return total_bytes_read;
+
             iov[curr_iov].iov_base =
                 (char *)iov[curr_iov].iov_base + bytes_read;
             iov[curr_iov].iov_len -= (size_t)bytes_read;
-
-            if (curr_iov == iov_count)
-                return total_bytes_read;
         }
 
         lwan_request_await_read(request, fd);