Initialize the tree data structures for a new zlib stream.
function tr_init() {

			l_desc.dyn_tree = dyn_ltree;
			l_desc.stat_desc = StaticTree.static_l_desc;

			d_desc.dyn_tree = dyn_dtree;
			d_desc.stat_desc = StaticTree.static_d_desc;

			bl_desc.dyn_tree = bl_tree;
			bl_desc.stat_desc = StaticTree.static_bl_desc;

			bi_buf = 0;
			bi_valid = 0;
			last_eob_len = 8; // enough lookahead for inflate

			// Initialize the first block of the first file:
			init_block();
		}