1 files changed, 1 insertions, 1 deletions

diff --git a/deflate.c b/deflate.c
index 7a9e05e..544521d 100644
--- a/deflate.c
+++ b/deflate.c
@@ -676,7 +676,7 @@ int ZEXPORT deflate (strm, flush)
     s = strm->state;
 
     if (strm->next_out == Z_NULL ||
-        (strm->next_in == Z_NULL && strm->avail_in != 0) ||
+        (strm->avail_in != 0 && strm->next_in == Z_NULL) ||
         (s->status == FINISH_STATE && flush != Z_FINISH)) {
         ERR_RETURN(strm, Z_STREAM_ERROR);
     }