diff --git a/lib/gunzip.c b/lib/gunzip.c
index 80b157f99eb4844dbade0925b0f20c0850d2bda5..da0c76c500d1cf2db8362ebc753defb61f1474ea 100644
--- a/lib/gunzip.c
+++ b/lib/gunzip.c
@@ -286,12 +286,11 @@ int zunzip(void *dst, int dstlen, unsigned char *src, unsigned long *lenp,
 	do {
 		r = inflate(&s, Z_FINISH);
 		if (stoponerr == 1 && r != Z_STREAM_END &&
-		    (s.avail_out == 0 || r != Z_BUF_ERROR)) {
+		    (s.avail_in == 0 || s.avail_out == 0 || r != Z_BUF_ERROR)) {
 			printf("Error: inflate() returned %d\n", r);
 			err = -1;
 			break;
 		}
-		s.avail_in = *lenp - offset - (int)(s.next_out - (unsigned char*)dst);
 	} while (r == Z_BUF_ERROR);
 	*lenp = s.next_out - (unsigned char *) dst;
 	inflateEnd(&s);