diff --git a/deflate.c b/deflate.c
index d368b25..e97bd87 100644
--- a/deflate.c
+++ b/deflate.c
@@ -1775,7 +1775,7 @@ local block_state deflate_stored(s, flush)
         return block_done;
 
     /* Fill the window with any remaining input. */
-    have = s->window_size - s->strstart - 1;
+    have = s->window_size - s->strstart;
     if (s->strm->avail_in > have && s->block_start >= (long)s->w_size) {
         /* Slide the window down. */
         s->block_start -= s->w_size;