+/* encoding/decoding */
+static uchar c_len[NC], pt_len[NPT];
+
+/* encoding */
+static ushort c_freq[2 * NC - 1], c_code[NC];
+static ushort p_freq[2 * NP - 1], pt_code[NPT];
+static ushort t_freq[2 * NT - 1];
+
+/*
+ size frequency bitlength Huffman coding
+ -----------------------------------------------------------
+ NC c_freq c_len c_code
+ NT t_freq pt_len pt_code
+ np p_freq pt_len pt_code
+ */
+
+/* decoding */
+static ushort c_table[4096], pt_table[256];
+