"""This module contains helper functions for working with checksums."""
# Copyright (C) 2008 Martin Sandve Alnes
#
# This file is part of Instant.
#
# Instant is free software: you can redistribute it and/or modify
# it under the terms of the GNU Lesser General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# Instant is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public License
# along with Instant. If not, see <http://www.gnu.org/licenses/>.
#
# Alternatively, Instant may be distributed under the terms of the BSD license.
from six import string_types
import io
import hashlib
from .output import instant_assert, instant_debug, instant_error
[docs]def compute_checksum(text="", filenames=[]):
"""
Get the checksum value of filename
modified based on Python24\Tools\Scripts\md5.py
"""
instant_assert(isinstance(text, string_types), "Expecting string.")
instant_assert(isinstance(filenames, (list, tuple)), "Expecting sequence.")
m = hashlib.new('sha1')
if text:
m.update(text.encode('utf-8'))
for filename in sorted(filenames):
instant_debug("Adding file '%s' to checksum." % filename)
try:
fp = io.open(filename, 'rb')
except IOError as e:
instant_error("Can't open file '%s': %s" % (filename, e))
try:
while True:
data = fp.read()
if not data:
break
m.update(data)
except IOError as e:
instant_error("I/O error reading '%s': %s" % (filename, e))
fp.close()
return m.hexdigest().lower()
def _test():
signature = "(Test signature)"
files = ["signatures.py", "__init__.py"]
print()
print("Signature:", repr(signature))
print("Checksum:", compute_checksum(signature, []))
print()
print("Files:", files)
print("Checksum:", compute_checksum("", files))
print()
if __name__ == "__main__":
_test()