Add inflateCodesUsed() function

Based on upstream commit 5370d99a2affe0b040550cffbc0ba8fa790594b3

1 files changed, 8 insertions, 0 deletions

diff --git a/inflate.c b/inflate.c
index 1f715db..f0a3415 100644
--- a/inflate.c
+++ b/inflate.c
@@ -1478,3 +1478,11 @@ long ZEXPORT inflateMark(z_stream *strm) {
     return ((long)(state->back) << 16) + (state->mode == COPY ? state->length :
             (state->mode == MATCH ? state->was - state->length : 0));
 }
+
+unsigned long ZEXPORT inflateCodesUsed(z_stream *strm) {
+    struct inflate_state *state;
+    if (strm == NULL || strm->state == NULL)
+        return (unsigned long)0 - 1;
+    state = (struct inflate_state *)strm->state;
+    return (unsigned long)(state->next - state->codes);
+}