Use a uniform approach for the largest value of an unsigned type.

1 files changed, 1 insertions, 1 deletions

diff --git a/inflate.c b/inflate.c
index 298479f..0f7e3e7 100644
--- a/inflate.c
+++ b/inflate.c
@@ -1496,7 +1496,7 @@ long ZEXPORT inflateMark(z_stream *strm) {
 unsigned long ZEXPORT inflateCodesUsed(z_stream *strm) {
     struct inflate_state *state;
     if (strm == NULL || strm->state == NULL)
-        return (unsigned long)0 - 1;
+        return (unsigned long)-1;
     state = (struct inflate_state *)strm->state;
     return (unsigned long)(state->next - state->codes);
 }