+#define USE_LZX_EXTRA_BITS_ARRAY
+
+#ifdef USE_LZX_EXTRA_BITS_ARRAY
+extern const u8 lzx_extra_bits[LZX_NUM_POSITION_SLOTS];
+#endif
+
+/* Given the number of a LZX position slot, return the number of extra bits that
+ * are needed to encode the match offset. */
+static inline unsigned
+lzx_get_num_extra_bits(unsigned position_slot)
+{
+#ifdef USE_LZX_EXTRA_BITS_ARRAY
+ /* Use a table */
+ return lzx_extra_bits[position_slot];
+#else
+ /* Calculate directly using a shift and subtraction. */
+ wimlib_assert(position_slot >= 2 && position_slot <= 37);
+ return (position_slot >> 1) - 1;
+#endif
+}
+
+extern const u32 lzx_position_base[LZX_NUM_POSITION_SLOTS];