diff --git a/extract.c b/extract.c
index d9866f9..0cb7bfc 100644
--- a/extract.c
+++ b/extract.c
@@ -3010,7 +3010,7 @@ __GDEF
 #endif
 
     G.inptr = (uch *)bstrm.next_in;
-    G.incnt = (G.inbuf + INBUFSIZ) - G.inptr;  /* reset for other routines */
+    G.incnt -= G.inptr - G.inbuf;       /* reset for other routines */
 
 uzbunzip_cleanup_exit:
     err = BZ2_bzDecompressEnd(&bstrm);