+#define USE_INDIRECT_NIDS 1
+
+#ifdef USE_INDIRECT_NIDS
+/*
+ * Use the high bit of ID_BLOCK_NMAX to indicate an INDIRECT block, thus
+ * freeing up the ID_BLOCK_NIDS to store an actual count. This allows us
+ * to use binary search on INDIRECT blocks.
+ */
+#undef ID_BLOCK_NMAXN
+#define ID_BLOCK_NMAXN(b) ((b)[ID_BLOCK_NMAX_OFFSET]&0x7fffffff)
+#undef ID_BLOCK_INDIRECT_VALUE
+#define ID_BLOCK_INDIRECT_VALUE 0x80000000
+#undef ID_BLOCK_INDIRECT
+#define ID_BLOCK_INDIRECT(b) (ID_BLOCK_NMAX(b) & ID_BLOCK_INDIRECT_VALUE)
+
+#endif /* USE_INDIRECT_NIDS */
+