这是一个CRC64的Python实现。它的行为（计算结果）与7Zip的结果相同（理应与xz utils也相同）。该类实现了hashlib._Hash接口。本代码部分使用ChatGPT生成，同时经过本人修改和测试。本人不保留任何权利，不承担任何责任。如有需要，可以随意使用。
以下使用code标签包括的是代码原文：
class CRC64Hash:
_poly = 0xC96C5795D7870F42
_seed = 0xFFFFFFFFFFFFFFFF
digest_size = 8
block_size = 1
_crc_table = [0x0000000000000000, 0xb32e4cbe03a75f6f, 0xf4843657a840a05b, 0x47aa7ae9abe7ff34, 0x7bd0c384ff8f5e33, 0xc8fe8f3afc28015c, 0x8f54f5d357cffe68, 0x3c7ab96d5468a107,
0xf7a18709ff1ebc66, 0x448fcbb7fcb9e309, 0x325b15e575e1c3d, 0xb00bfde054f94352, 0x8c71448d0091e255, 0x3f5f08330336bd3a, 0x78f572daa8d1420e, 0xcbdb3e64ab761d61,
0x7d9ba13851336649, 0xceb5ed8652943926, 0x891f976ff973c612, 0x3a31dbd1fad4997d, 0x64b62bcaebc387a, 0xb5652e02ad1b6715, 0xf2cf54eb06fc9821, 0x41e11855055bc74e,
0x8a3a2631ae2dda2f, 0x39146a8fad8a8540, 0x7ebe1066066d7a74, 0xcd905cd805ca251b, 0xf1eae5b551a2841c, 0x42c4a90b5205db73, 0x56ed3e2f9e22447, 0xb6409f5cfa457b28,
0xfb374270a266cc92, 0x48190ecea1c193fd, 0xfb374270a266cc9, 0xbc9d3899098133a6, 0x80e781f45de992a1, 0x33c9cd4a5e4ecdce, 0x7463b7a3f5a932fa, 0xc74dfb1df60e6d95,
0xc96c5795d7870f4, 0xbfb889c75edf2f9b, 0xf812f32ef538d0af, 0x4b3cbf90f69f8fc0, 0x774606fda2f72ec7, 0xc4684a43a15071a8, 0x83c230aa0ab78e9c, 0x30ec7c140910d1f3,
0x86ace348f355aadb, 0x3582aff6f0f2f5b4, 0x7228d51f5b150a80, 0xc10699a158b255ef, 0xfd7c20cc0cdaf4e8, 0x4e526c720f7dab87, 0x9f8169ba49a54b3, 0xbad65a25a73d0bdc,
0x710d64410c4b16bd, 0xc22328ff0fec49d2, 0x85895216a40bb6e6, 0x36a71ea8a7ace989, 0xadda7c5f3c4488e, 0xb9f3eb7bf06317e1, 0xfe5991925b84e8d5, 0x4d77dd2c5823b7ba,
0x64b62bcaebc387a1, 0xd7986774e864d8ce, 0x90321d9d438327fa, 0x231c512340247895, 0x1f66e84e144cd992, 0xac48a4f017eb86fd, 0xebe2de19bc0c79c9, 0x58cc92a7bfab26a6,
0x9317acc314dd3bc7, 0x2039e07d177a64a8, 0x67939a94bc9d9b9c, 0xd4bdd62abf3ac4f3, 0xe8c76f47eb5265f4, 0x5be923f9e8f53a9b, 0x1c4359104312c5af, 0xaf6d15ae40b59ac0,
0x192d8af2baf0e1e8, 0xaa03c64cb957be87, 0xeda9bca512b041b3, 0x5e87f01b11171edc, 0x62fd4976457fbfdb, 0xd1d305c846d8e0b4, 0x96797f21ed3f1f80, 0x2557339fee9840ef,
0xee8c0dfb45ee5d8e, 0x5da24145464902e1, 0x1a083bacedaefdd5, 0xa9267712ee09a2ba, 0x955cce7fba6103bd, 0x267282c1b9c65cd2, 0x61d8f8281221a3e6, 0xd2f6b4961186fc89,
0x9f8169ba49a54b33, 0x2caf25044a02145c, 0x6b055fede1e5eb68, 0xd82b1353e242b407, 0xe451aa3eb62a1500, 0x577fe680b58d4a6f, 0x10d59c691e6ab55b, 0xa3fbd0d71dcdea34,
0x6820eeb3b6bbf755, 0xdb0ea20db51ca83a, 0x9ca4d8e41efb570e, 0x2f8a945a1d5c0861, 0x13f02d374934a966, 0xa0de61894a93f609, 0xe7741b60e174093d, 0x545a57dee2d35652,
0xe21ac88218962d7a, 0x5134843c1b317215, 0x169efed5b0d68d21, 0xa5b0b26bb371d24e, 0x99ca0b06e7197349, 0x2ae447b8e4be2c26, 0x6d4e3d514f59d312, 0xde6071ef4cfe8c7d,
0x15bb4f8be788911c, 0xa6950335e42fce73, 0xe13f79dc4fc83147, 0x521135624c6f6e28, 0x6e6b8c0f1807cf2f, 0xdd45c0b11ba09040, 0x9aefba58b0476f74, 0x29c1f6e6b3e0301b,
0xc96c5795d7870f42, 0x7a421b2bd420502d, 0x3de861c27fc7af19, 0x8ec62d7c7c60f076, 0xb2bc941128085171, 0x192d8af2baf0e1e, 0x4638a2468048f12a, 0xf516eef883efae45,
0x3ecdd09c2899b324, 0x8de39c222b3eec4b, 0xca49e6cb80d9137f, 0x7967aa75837e4c10, 0x451d1318d716ed17, 0xf6335fa6d4b1b278, 0xb199254f7f564d4c, 0x2b769f17cf11223,
0xb4f7f6ad86b4690b, 0x7d9ba1385133664, 0x4073c0fa2ef4c950, 0xf35d8c442d53963f, 0xcf273529793b3738, 0x7c0979977a9c6857, 0x3ba3037ed17b9763, 0x888d4fc0d2dcc80c,
0x435671a479aad56d, 0xf0783d1a7a0d8a02, 0xb7d247f3d1ea7536, 0x4fc0b4dd24d2a59, 0x3886b22086258b5e, 0x8ba8fe9e8582d431, 0xcc0284772e652b05, 0x7f2cc8c92dc2746a,
0x325b15e575e1c3d0, 0x8175595b76469cbf, 0xc6df23b2dda1638b, 0x75f16f0cde063ce4, 0x498bd6618a6e9de3, 0xfaa59adf89c9c28c, 0xbd0fe036222e3db8, 0xe21ac88218962d7,
0xc5fa92ec8aff7fb6, 0x76d4de52895820d9, 0x317ea4bb22bfdfed, 0x8250e80521188082, 0xbe2a516875702185, 0xd041dd676d77eea, 0x4aae673fdd3081de, 0xf9802b81de97deb1,
0x4fc0b4dd24d2a599, 0xfceef8632775faf6, 0xbb44828a8c9205c2, 0x86ace348f355aad, 0x34107759db5dfbaa, 0x873e3be7d8faa4c5, 0xc094410e731d5bf1, 0x73ba0db070ba049e,
0xb86133d4dbcc19ff, 0xb4f7f6ad86b4690, 0x4ce50583738cb9a4, 0xffcb493d702be6cb, 0xc3b1f050244347cc, 0x709fbcee27e418a3, 0x3735c6078c03e797, 0x841b8ab98fa4b8f8,
0xadda7c5f3c4488e3, 0x1ef430e13fe3d78c, 0x595e4a08940428b8, 0xea7006b697a377d7, 0xd60abfdbc3cbd6d0, 0x6524f365c06c89bf, 0x228e898c6b8b768b, 0x91a0c532682c29e4,
0x5a7bfb56c35a3485, 0xe955b7e8c0fd6bea, 0xaeffcd016b1a94de, 0x1dd181bf68bdcbb1, 0x21ab38d23cd56ab6, 0x9285746c3f7235d9, 0xd52f0e859495caed, 0x6601423b97329582,
0xd041dd676d77eeaa, 0x636f91d96ed0b1c5, 0x24c5eb30c5374ef1, 0x97eba78ec690119e, 0xab911ee392f8b099, 0x18bf525d915feff6, 0x5f1528b43ab810c2, 0xec3b640a391f4fad,
0x27e05a6e926952cc, 0x94ce16d091ce0da3, 0xd3646c393a29f297, 0x604a2087398eadf8, 0x5c3099ea6de60cff, 0xef1ed5546e415390, 0xa8b4afbdc5a6aca4, 0x1b9ae303c601f3cb,
0x56ed3e2f9e224471, 0xe5c372919d851b1e, 0xa26908783662e42a, 0x114744c635c5bb45, 0x2d3dfdab61ad1a42, 0x9e13b115620a452d, 0xd9b9cbfcc9edba19, 0x6a978742ca4ae576,
0xa14cb926613cf817, 0x1262f598629ba778, 0x55c88f71c97c584c, 0xe6e6c3cfcadb0723, 0xda9c7aa29eb3a624, 0x69b2361c9d14f94b, 0x2e184cf536f3067f, 0x9d36004b35545910,
0x2b769f17cf112238, 0x9858d3a9ccb67d57, 0xdff2a94067518263, 0x6cdce5fe64f6dd0c, 0x50a65c93309e7c0b, 0xe388102d33392364, 0xa4226ac498dedc50, 0x170c267a9b79833f,
0xdcd7181e300f9e5e, 0x6ff954a033a8c131, 0x28532e49984f3e05, 0x9b7d62f79be8616a, 0xa707db9acf80c06d, 0x14299724cc279f02, 0x5383edcd67c06036, 0xe0ada17364673f59]
def __init__(self, data=None, seed=0xFFFFFFFFFFFFFFFF, poly=None, value=None):
if poly is not None:
self._poly = poly
CRC64Hash.init_crc_table()
self._seed = seed
if value is None:
self._value = seed
else:
self._value = value
if data is not None:
self.update(data)
# This is the algorithm without hash table
# def update(self, data):
# for b in data:
# self._value = self._value ^ b
# for i in range(8):
# if self._value & 1:
# self._value = (self._value >> 1) ^ self._poly
# else:
# self._value = self._value >> 1
def update(self, data):
"""Updates the CRC64 hash with the provided bytes"""
if not isinstance(data, bytes):
data = bytes(data)
for byte in data:
self._value = self._crc_table[(
self._value ^ byte) & 0xFF] ^ (self._value >> 8)
def digest(self):
return (self._value ^ self._seed).to_bytes(self.digest_size, byteorder='big', signed=False)
def hexdigest(self):
return self.digest().hex()
def copy(self):
new_hash = CRC64Hash(seed=self._seed, poly=self._poly)
return new_hash
# This is the methord used to generate the hash table. If Poly changed, you need to call it first
@classmethod
def init_crc_table(cls):
"""Initializes the memoized lookup table for CRC64 calculation"""
cls._crc_table = [0] * 256
for i in range(256):
crc = i
for j in range(8):
if crc & 1:
crc = (crc >> 1) ^ cls._poly
else:
crc >>= 1
cls._crc_table[i] = crc
def crc64(data=None, seed=0xFFFFFFFFFFFFFFFF, poly=0xC96C5795D7870F42, value=None):
return CRC64Hash(data, seed, poly, value)
你可以完整复制这段代码，并将其保存到名为CRC64.py（点击下载）的文件中。然后直接调用crc64()或CRC64Hash()来使用。其使用方法与其他hashlib的哈希类型相同。
这段代码中难以理解的，人类不可读的部分（_crc_table），是用来加速运算的哈希表，该表与多项式值相关。我想，在你了解之后，便可以放心使用。该表使用CRC64Hash.init_crc_table()预生成，并硬编码到程序中。如果初始化时给定非默认多项式（_poly），哈希表会在构造函数中被重新计算。
如果你出于学习目的阅读代码，你可以在代码中找到一个经过注释的update()函数，该函数不使用哈希表加速运算。该函数同样部分由ChatGPT生成。经过简单修改和测试，其行为与使用哈希表计算的结果相同。
如果你发现了代码中的错误或有任何改进提议，可以到本站的Github页面提交issue。同样的，你也无法对你所提交更改的代码保留任何的权利。
本代码部分使用ChatGPT生成，并经过本人修改，以使之正确运行。我不能确定AI生成内容的现实来源。如有侵犯到你的权利，本站的Github页面提交issue。