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benc: Bencode encoding and decoding library

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Bencode encoding and decoding library.

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Versions [RSS] 0.1.0.0, 0.1.1.0
Change log CHANGELOG.md
Dependencies base (>=4.14 && <5.0), bytestring (>=0.10.10 && <0.13), containers (>=0.6.2.1 && <0.8), primitive (>=0.9.0 && <0.10), text (>=1.2.3.2 && <2.2), transformers (>=0.5.6.2 && <0.7), vector (>=0.13.1 && <0.14) [details]
Tested with ghc ==8.10.1, ghc ==8.10.7, ghc ==9.0.2, ghc ==9.2.8, ghc ==9.4.8, ghc ==9.6.3, ghc ==9.8.1
License MIT
Author Soumik Sarkar
Maintainer soumiksarkar.3120@gmail.com
Category Codec
Home page https://github.com/meooow25/benc
Bug tracker https://github.com/meooow25/benc/issues
Uploaded by meooow at 2023-12-05T14:01:27Z
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Downloads 85 total (4 in the last 30 days)
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Status Docs available [build log]
Last success reported on 2023-12-05 [all 1 reports]

Readme for benc-0.1.1.0

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benc

Hackage Haskell-CI

Bencode encoding and decoding library

Bencode

Bencode is a simple encoding format for loosely structured data, comparable to JSON. It is used primarily in the BitTorrent protocol. For a description of the format see

Features

This library offers

  • A nice API
  • Correctness
  • Speed

This library does not attempt to support

  • Lazy or incremental parsing
  • Failing with detailed error messages

Getting started

Please see the Haddocks for Data.Bencode.Decode and Data.Bencode.Encode.

Alternatives

There are currently three other Bencode libraries on Hackage:

All of these are in some combination of buggy, slow, and unmaintained.

Click for details
  • bencode:
    • Bugs (e.g. crashes on input "i-e")
    • Very slow parsing
    • No high-level encoding API
    • [Minor] Lax parsing (e.g. admits the invalid "i-0e")
  • AttoBencode
    • Slow parsing
    • [Minor] Lax parsing (e.g. admits the invalid "i-0e")
  • bencoding
    • Bugs (e.g. crashes on parsing non-UTF-8 into Text)
    • Questionable design of dict encoding/decoding API, where human error can lead to mis-parsing Bencode or writing invalid Bencode.
    • [Minor] Lax parsing (e.g. admits the invalid "i-0e")

API comparison

See the benchmark file as a comparison point of the library APIs.

Benchmarks

Below is a comparison of decoding and encoding of two torrent files, performed with GHC 9.6.3. See the benchmark file for details.

Decoding

Library crossref time alloc ubuntu time alloc
benc 21.3 ms ± 902 μs 24 MB 1.30 μs ± 90 ns 3.6 KB
bencode 218 ms ± 7.7 ms 737 MB 29.0 μs ± 2.6 μs 121 KB
AttoBencode 44.6 ms ± 4.0 ms 129 MB 3.01 μs ± 102 ns 17 KB
bencoding 39.1 ms ± 2.3 ms 104 MB 2.44 μs ± 175 ns 15 KB

Note: bencode parses from a lazy ByteString unlike the rest which parse from strict ByteStrings, and so is expected to be a little slower.

Encoding

Library crossref time alloc ubuntu time alloc
benc 9.17 ms ± 487 μs 42 MB 1.58 μs ± 101 ns 11 KB
bencode 37.8 ms ± 860 μs 113 MB 3.17 μs ± 174 ns 19 KB
AttoBencode 19.7 ms ± 1.8 ms 109 MB 10.1 μs ± 993 ns 295 KB
bencoding 11.9 ms ± 916 μs 67 MB 1.81 μs ± 129 ns 15 KB

Note: AttoBencode encodes to a strict ByteString via a lazy ByteString, unlike the rest, which only prepare the lazy ByteString. As such, it is expected to be slower.

Contributing

Questions, bug reports, documentation improvements, code contributions welcome! Please open an issue as the first step.