buffer-builder: Library for efficiently building up buffers, one piece at a time

Data.BufferBuilder is an efficient library for incrementally building up ByteStrings, one chunk at a time. Early benchmarks show it is over twice as fast as ByteString Builder, primarily because BufferBuilder is built upon an ST-style restricted monad and mutable state instead of ByteString Builder's monoidal AST.

Internally, BufferBuilder is backed by a few C functions. Examination of GHC's output shows nearly optimal code generation with no intermediate thunks -- and thus, continuation passing and its associated indirect jumps and stack traffic only occur when BufferBuilder is asked to append a non-strict ByteString.

I benchmarked four approaches with a URL encoding benchmark:

• State monad, concatenating ByteStrings: 6.98 us

• State monad, ByteString Builder: 2.48 us

• Crazy explicit RealWorld baton passing with unboxed state: 28.94 us (GHC generated really awful code for this, but see the revision history for the technique)

• C + FFI + ReaderT: 1.11 us

Using BufferBuilder is very simple:

import qualified Data.BufferBuilder as BB

let byteString = BB.runBufferBuilder $ do
      BB.appendBS "http"
      BB.appendChar8 '/'
      BB.appendBS "//"

This package also provides Data.BufferBuilder.Utf8 for generating UTF-8 buffers and Data.BufferBuilder.Json for encoding data structures into JSON.

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Downloads

• buffer-builder-0.2.4.7.tar.gz [browse] (Cabal source package)
• Package description (as included in the package)

Maintainer's Corner

Package maintainers

• chadaustin, afriesen

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• edit package information

Candidates

• 0.1.0.0, 0.2.0.0, 0.2.0.1, 0.2.0.3, 0.2.1.0