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volatility3/volatility/framework/layers/scanners/multiregexp.py
T

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Python

# This file was contributed to the Volatility Framework Version 3.
# Copyright (C) 2018 Volatility Foundation.
#
# THE LICENSED WORK IS PROVIDED UNDER THE TERMS OF THE Volatility Contributors
# Public License V1.0("LICENSE") AS FIRST COMPLETED BY: Volatility Foundation,
# Inc. ANY USE, PUBLIC DISPLAY, PUBLIC PERFORMANCE, REPRODUCTION OR DISTRIBUTION
# OF, OR PREPARATION OF SUBSEQUENT WORKS, DERIVATIVE WORKS OR DERIVED WORKS BASED
# ON, THE LICENSED WORK CONSTITUTES RECIPIENT'S ACCEPTANCE OF THIS LICENSE AND ITS
# TERMS, WHETHER OR NOT SUCH RECIPIENT READS THE TERMS OF THE LICENSE. "LICENSED
# WORK,” “RECIPIENT" AND “DISTRIBUTOR" ARE DEFINED IN THE LICENSE. A COPY OF THE
# LICENSE IS LOCATED IN THE TEXT FILE ENTITLED "LICENSE.txt" ACCOMPANYING THE
# CONTENTS OF THIS FILE. IF A COPY OF THE LICENSE DOES NOT ACCOMPANY THIS FILE, A
# COPY OF THE LICENSE MAY ALSO BE OBTAINED AT THE FOLLOWING WEB SITE:
# https://www.volatilityfoundation.org/license/vcpl_v1.0
#
# Software distributed under the License is distributed on an "AS IS" basis,
# WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License for the
# specific language governing rights and limitations under the License.
#
import re
from typing import Generator, List, Tuple, Union
class MultiRegexp(object):
"""Algorithm for multi-string matching"""
def __init__(self) -> None:
self._pattern_strings = [] # type: List[bytes]
self._regex = re.compile(b'')
def add_pattern(self, pattern: bytes) -> None:
self._pattern_strings.append(pattern)
def preprocess(self) -> None:
if not self._pattern_strings:
raise ValueError("No strings to compile into a regular expression")
self._regex = re.compile(b'|'.join(map(re.escape, self._pattern_strings)))
def search(self, haystack: bytes) \
-> Generator[Tuple[int, Union[str, bytes]], None, None]:
if not isinstance(haystack, bytes):
raise TypeError("Search haystack must be a byte string")
if not self._regex.pattern:
raise ValueError("MultiRegexp cannot be used with an empty set of search strings")
for match in re.finditer(self._regex, haystack):
yield (match.start(0), match.group())
if __name__ == '__main__':
import multistring_testrig
multistring_testrig.tester(MultiRegexp())