From e554695638228b846d49657f31eeff0ca4680e8a Mon Sep 17 00:00:00 2001

From: Mark Adler <madler@alumni.caltech.edu>

Date: Thu, 15 Dec 2022 09:07:13 -0800

Subject: [PATCH] Fix bug in deflateBound() for level 0 and memLevel 9.

memLevel 9 would cause deflateBound() to assume the use of fixed

blocks, even if the compression level was 0, which forces stored

blocks. That could result in a bound less than the size of the

compressed data. Now level 0 always uses the stored blocks bound.

---

 deflate.c | 3 ++-

 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/deflate.c b/deflate.c

index cd538b8..4a512e1 100644

--- a/deflate.c

+++ b/deflate.c

@@ -752,7 +752,8 @@ uLong ZEXPORT deflateBound(strm, sourceLen)

     /* if not default parameters, return one of the conservative bounds */

     if (s->w_bits != 15 || s->hash_bits != 8 + 7)

-        return (s->w_bits <= s->hash_bits ? fixedlen : storelen) + wraplen;

+        return (s->w_bits <= s->hash_bits && s->level ? fixedlen : storelen) +

+               wraplen;

     /* default settings: return tight bound for that case -- ~0.03% overhead

        plus a small constant */

-- 

2.38.1