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46 lines
1.3 KiB
Python
46 lines
1.3 KiB
Python
import hashlib
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from typing import cast, Any, BinaryIO
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def feed_file(h: Any, f: BinaryIO) -> None:
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"""Feed data read from an open file into the hashlib instance."""
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while True:
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data = f.read(65536)
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if len(data) == 0:
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# end of file
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break
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h.update(data)
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def feed_file_path(h: Any, path: str) -> None:
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"""Feed data read from a file (to be opened by this function) into the hashlib instance."""
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with open(path, 'rb') as f:
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feed_file(h, f)
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def file_digest(algorithm: Any, path: str) -> str:
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"""Calculate the digest of a file and return it in hexadecimal notation."""
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h = algorithm()
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feed_file_path(h, path)
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return cast(str, h.hexdigest())
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def guess_digest_algorithm(digest: str) -> Any:
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l = len(digest)
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if l == 32:
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return hashlib.md5
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elif l == 40:
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return hashlib.sha1
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elif l == 64:
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return hashlib.sha256
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elif l == 128:
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return hashlib.sha512
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else:
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return None
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def verify_file_digest(path: str, expected_digest: str) -> bool:
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"""Verify the digest of a file, and return True if the digest matches with the given expected digest."""
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algorithm = guess_digest_algorithm(expected_digest)
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assert(algorithm is not None)
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return file_digest(algorithm, path) == expected_digest
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