Hywan / fastdiff

A fast native implementation of diff algorithm with a pure Python fallback

fastdiff

fastdiff is a re-implementation of difflib in pure Rust compiled to WebAssembly to speedup different language integrations:

• Python: via Wasmer, falling back to difflib compare.

Install

Python

To install fastdiff in Python, you just need to do:

pip install fastdiff

And then, use it in Python like this:

from fastdiff import compare

str1 = 'hello\nwasm\n'
str2 = 'hello\npython\n'

print(compare(str1, str2))

Benchmarks

Python

When comparing strings with 300 lines, the WebAssembly based approach is about 75 times faster than the pure Python approach.

------------------------------------------------------------------------------------------------ benchmark: 2 tests ------------------------------------------------------------------------------------------------
Name (time in ms)                         Min                    Max                   Mean              StdDev                 Median                 IQR            Outliers     OPS            Rounds  Iterations
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
test_benchmark_content_native        137.9896 (1.0)         145.8701 (1.0)         141.2983 (1.0)        2.8708 (1.0)         140.5982 (1.0)        4.2806 (1.0)           3;0  7.0772 (1.0)           7           1
test_benchmark_content_base       10,665.8390 (77.29)    11,141.3282 (76.38)    10,837.7984 (76.70)    183.8493 (64.04)    10,817.5194 (76.94)    206.9630 (48.35)         1;0  0.0923 (0.01)          5           1
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

Building

For building the WebAssembly file, you need Rust and the wasm32 target.

# Install Rustup
curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh

# Add wasm32 target
rustup target add wasm32-unknown-unknown

And then, run:

make build

Testing

For testing in Python you can do:

make test_python