Fix bi_valid handling in deflate_quick()

The attached test started failing after commit ad89d5131b29 ("Don't
write end of last block when returning finish_started."): either with
"bi_buf not flushed" message in debug builds, or by producing corrupted
output in release builds.

The problem is that we must not return finish_started when bi_buf is
not empty, because the bits there will be lost. Fix by checking that
bi_valid is not 0.

1 files changed, 1 insertions, 1 deletions

diff --git a/deflate_quick.c b/deflate_quick.c
index 268cce8..d749b3a 100644
--- a/deflate_quick.c
+++ b/deflate_quick.c
@@ -65,7 +65,7 @@ Z_INTERNAL block_state deflate_quick(deflate_state *s, int flush) {
         if (UNLIKELY(s->pending + ((BIT_BUF_SIZE + 7) >> 3) >= s->pending_buf_size)) {
             flush_pending(s->strm);
             if (s->strm->avail_out == 0) {
-                return (last && s->strm->avail_in == 0) ? finish_started : need_more;
+                return (last && s->strm->avail_in == 0 && s->bi_valid == 0) ? finish_started : need_more;
             }
         }