1  # SPDX-FileCopyrightText: 2019 4am
 2  #
 3  # SPDX-License-Identifier: MIT
 4  
 5  import re
 6  
 7  WILDCARD = b'\x97'
 8  WILDSTR  = "97"
 9  
10  def wild(source_bytes, search_bytes):
11      """Search source_bytes (bytes object) for the first instance of search_bytes (bytes_object). search_bytes may contain WILDCARD, which matches any single byte (like "." in a regular expression). Returns index of first match, or -1 if no matches."""
12      search_bytes = re.escape(search_bytes).replace(WILDCARD, b'.')
13      match = re.search(search_bytes, source_bytes)
14      if match:
15          return match.start()
16      return -1
17  
18  def wild_at(offset, source_bytes, search_bytes):
19      """returns True if the search_bytes was found in source_bytes at offset (search_bytes may include wildcards), otherwise False"""
20      offset = wild(source_bytes[offset:], search_bytes)
21      return offset == 0
22  
23  def at(offset, source_bytes, search_bytes):
24      """returns True if the exact bytes search_bytes was found in source_bytes at offset (no wildcards), otherwise False"""
25      return source_bytes[offset:offset+len(search_bytes)] == search_bytes