diff --git a/src/gen-ucd.py b/src/gen-ucd.py
new file mode 100755
index 000000000..d97085e69
--- /dev/null
+++ b/src/gen-ucd.py
@@ -0,0 +1,46 @@
+#!/usr/bin/env python
+
+from __future__ import print_function, division, absolute_import
+
+import io, os.path, sys
+
+if len (sys.argv) != 2:
+	print ("usage: ./gen-ucd ucdxml-file", file=sys.stderr)
+	sys.exit (1)
+
+import youseedy, packTab
+
+ucd = youseedy.load_ucdxml (sys.argv[1])
+
+gc = [u['gc'] for u in ucd]
+ccc = [int(u['ccc']) for u in ucd]
+sc = [u['sc'] for u in ucd]
+bmg = [int(v, 16) - int(u) if v else 0 for u,v in enumerate(u['bmg'] for u in ucd)]
+dm = {i:tuple(int(v, 16) for v in u['dm'].split()) for i,u in enumerate(ucd)
+      if u['dm'] != '#' and u['dt'] == 'can' and not (0xAC00 <= i < 0xAC00+11172)}
+
+gc_set = set(gc)
+gc_ccc_non0 = set((cat,klass) for cat,klass in zip(gc,ccc) if klass)
+gc_bmg_non0 = set((cat,mirr) for cat,mirr in zip(gc, bmg) if mirr)
+sc_set = set(sc)
+dm2 = set(v for v in dm.values() if len(v) == 2)
+dm2diff = set(v[1] - v[0] for v in dm2)
+dm1 = set(v[0] for i,v in dm.items() if len(v) == 1)
+dmx = set(v for v in dm.values() if len(v) not in (1,2))
+assert not dmx
+
+print(len(sorted(gc_set)))
+print(len(sorted(gc_ccc_non0)))
+print(len(sorted(gc_bmg_non0)))
+print("GC, CCC, and BMG fit in one byte. Compress together.")
+print()
+
+print(len(sorted(sc_set)))
+print("SC fits in one byte.  Compress separately.")
+print()
+
+print(len(dm))
+print(len(dm1), min(dm1), max(dm1))
+print(len(dm2))
+#print(sorted(dm2diff))
+print(len(sorted(set(v // 512 for v in dm1))))