mercurial/node.py

Fix bdiff test failures on AIX.

The test fails when, in the call to calloc(), the number of elements (bn)
is 0. In that case, calloc() on AIX will return NULL, while the code expects
a valid heap pointer. Both results are permissible under C99, Unix98 etc.

Work around by ensuring that at least 1 element is requested.

"""
node.py - basic nodeid manipulation for mercurial

Copyright 2005, 2006 Matt Mackall <[e-mail]>

This software may be used and distributed according to the terms
of the GNU General Public License, incorporated herein by reference.
"""

import binascii

nullrev = -1
nullid = "\0" * 20

# This ugly style has a noticeable effect in manifest parsing
hex = binascii.hexlify
bin = binascii.unhexlify

def short(node):
    return hex(node[:6])