bytecheck

A small library for byte-level comparison and verification between two files or byte sequences, built on top of adamlibrary's C extension modules.

This is meant to be used as a library first. Importing bytecheck doesn't parse argv or touch stdin - the CLI is just a thin optional layer on top.

Install

pip install -e .

Library usage

import bytecheck

data_a = open("file1.bin", "rb").read()
data_b = open("file2.bin", "rb").read()

result = bytecheck.verify(data_a, data_b)
print(result["match_ratio"])       # e.g. 85.71
print(result["identical"])          # True/False
print(result["mismatched_offsets"]) # list of byte offsets that differ

# Convenience wrappers
bytecheck.is_identical(data_a, data_b)
bytecheck.match_ratio(data_a, data_b)

verify() returns a plain dict:

Optional CLI

Installing this package also registers a bytecheck console script, and the package can be run directly as a module:

bytecheck file1.bin file2.bin
python -m bytecheck file1.bin file2.bin --chunk-size 16
python -m bytecheck --text "hello world" --text2 "hello worle"
python -m bytecheck file1.bin file2.bin --quiet   # just IDENTICAL/DIFFERENT + exit code

CLI flags:

C backend usage

Note: the binding of datasetname.memcmp takes its arguments as C strings, which cannot contain an embedded null byte. Real binary data can contain 0x00, so each null byte is remapped to 0x01 on both sides before comparing chunks. This is a simple workaround, not a perfect one - null support may be added to adamlibrary itself in the future, since this is one of the modules in the adamlibrary infrastructure. A genuine 0x00 vs 0x01 difference at the same offset can be masked by the remap, but that's an acceptable trade-off for a spot check of similarity between two byte streams.