+ * input size.
+ *
+ * +1 to take into account that the buffer for compressed data is 1 byte
+ * smaller than the buffer for uncompressed data.
+ *
+ * +4 to take into account that init_output_bitstream() requires at
+ * least 4 bytes of data. */
+ if (uncompressed_len < XPRESS_NUM_SYMBOLS / 2 + 1 + 4)