Add deflateUsed() function to get the used bits in the last byte.

This returns the number of used bits in the last byte of a stream
that has just been compressed with deflate.

1 files changed, 8 insertions, 0 deletions

diff --git a/deflate.c b/deflate.c
index cbdd880..0c9aa6d 100644
--- a/deflate.c
+++ b/deflate.c
@@ -720,6 +720,14 @@ int ZEXPORT deflatePending(z_streamp strm, unsigned *pending, int *bits) {
 }
 
 /* ========================================================================= */
+int ZEXPORT deflateUsed(z_streamp strm, int *bits) {
+    if (deflateStateCheck(strm)) return Z_STREAM_ERROR;
+    if (bits != Z_NULL)
+        *bits = strm->state->bi_used;
+    return Z_OK;
+}
+
+/* ========================================================================= */
 int ZEXPORT deflatePrime(z_streamp strm, int bits, int value) {
     deflate_state *s;
     int put;