在Python中比较二进制文件 [英] Diffing Binary Files In Python
问题描述
我有两个二进制文件。它们看起来像这样,但是数据更加随机:
I've got two binary files. They look something like this, but the data is more random:
文件A:
FF FF FF FF 00 00 00 00 FF FF 44 43 42 41 FF FF ...
文件B:
41 42 43 44 00 00 00 00 44 43 42 41 40 39 38 37 ...
我想要的是这样的称呼:
What I'd like is to call something like:
>>> someDiffLib.diff(file_a_data, file_b_data)
并收到以下内容:
[Match(pos=4, length=4)]
表示在两个文件中,位置4的字节对于4个字节都是相同的。序列 44 43 42 41
不匹配,因为它们在每个文件中的位置都不相同。
Indicating that in both files the bytes at position 4 are the same for 4 bytes. The sequence 44 43 42 41
would not match because they're not in the same positions in each file.
有没有可以帮我做个比较的图书馆?还是我应该编写循环进行比较?
Is there a library that will do the diff for me? Or should I just write the loops to do the comparison?
推荐答案
您可以使用 itertools.groupby()
为此,下面是一个示例:
You can use itertools.groupby()
for this, here is an example:
from itertools import groupby
# this just sets up some byte strings to use, Python 2.x version is below
# instead of this you would use f1 = open('some_file', 'rb').read()
f1 = bytes(int(b, 16) for b in 'FF FF FF FF 00 00 00 00 FF FF 44 43 42 41 FF FF'.split())
f2 = bytes(int(b, 16) for b in '41 42 43 44 00 00 00 00 44 43 42 41 40 39 38 37'.split())
matches = []
for k, g in groupby(range(min(len(f1), len(f2))), key=lambda i: f1[i] == f2[i]):
if k:
pos = next(g)
length = len(list(g)) + 1
matches.append((pos, length))
或者使用列表理解与上述相同:
Or the same thing as above using a list comprehension:
matches = [(next(g), len(list(g))+1)
for k, g in groupby(range(min(len(f1), len(f2))), key=lambda i: f1[i] == f2[i])
if k]
以下是使用Python 2.x的示例设置:
Here is the setup for the example if you are using Python 2.x:
f1 = ''.join(chr(int(b, 16)) for b in 'FF FF FF FF 00 00 00 00 FF FF 44 43 42 41 FF FF'.split())
f2 = ''.join(chr(int(b, 16)) for b in '41 42 43 44 00 00 00 00 44 43 42 41 40 39 38 37'.split())
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