base16

A pure implementation of base16 encoding & decoding on strict ByteStrings.

Usage

A sample GHCi session:

  > :set -XOverloadedStrings
  >
  > -- import qualified
  > import qualified Data.ByteString.Base16 as B16
  >
  > -- simple base16 encoding and decoding
  > B16.encode "hello world"
  "68656c6c6f20776f726c64"
  >
  > B16.decode "68656c6c6f20776f726c64"
  Just "hello world"

Documentation

Haddocks (API documentation, etc.) are hosted at docs.ppad.tech/base16.

Performance

The aim is best-in-class performance for pure, highly-auditable Haskell code. We could go slightly faster by direct allocation and writes, but we get pretty close to the best impure versions with only builders.

Current benchmark figures on 1kb inputs on my mid-2020 MacBook Air look like (use cabal bench to run the benchmark suite):

  benchmarking encode/ppad-base16
  time                 5.929 μs   (5.847 μs .. 6.013 μs)
                       0.999 R²   (0.998 R² .. 0.999 R²)
  mean                 5.975 μs   (5.913 μs .. 6.057 μs)
  std dev              233.1 ns   (172.4 ns .. 310.0 ns)

  benchmarking decode/ppad-base16
  time                 4.942 μs   (4.884 μs .. 4.995 μs)
                       0.999 R²   (0.998 R² .. 0.999 R²)
  mean                 4.908 μs   (4.854 μs .. 4.964 μs)
  std dev              176.8 ns   (150.3 ns .. 214.3 ns)
  variance introduced by outliers: 46% (moderately inflated)

Security

This library aims at the maximum security achievable in a garbage-collected language under an optimizing compiler such as GHC, in which strict constant-timeness can be challenging to achieve.

If you discover any vulnerabilities, please disclose them via [email protected].

Development

You'll require Nix with flake support enabled. Enter a development shell with:

$ nix develop

Then do e.g.:

$ cabal repl ppad-base16

to get a REPL for the main library.