diff --git a/mercurial/node.py b/mercurial/node.py
new file mode 100644
--- /dev/null
+++ b/mercurial/node.py
@@ -0,0 +1,36 @@
+"""
+node.py - basic nodeid manipulation for mercurial
+
+Copyright 2005 Matt Mackall <mpm@selenic.com>
+
+This software may be used and distributed according to the terms
+of the GNU General Public License, incorporated herein by reference.
+"""
+
+import sha, binascii
+
+nullid = "\0" * 20
+
+def hex(node):
+    return binascii.hexlify(node)
+
+def bin(node):
+    return binascii.unhexlify(node)
+
+def short(node):
+    return hex(node[:6])
+
+def hash(text, p1, p2):
+    """generate a hash from the given text and its parent hashes
+
+    This hash combines both the current file contents and its history
+    in a manner that makes it easy to distinguish nodes with the same
+    content in the revision graph.
+    """
+    l = [p1, p2]
+    l.sort()
+    s = sha.new(l[0])
+    s.update(l[1])
+    s.update(text)
+    return s.digest()
+