An efficient finite map from bytestrings to values.
An efficient finite map from bytestrings to values.
The implementation is based on big-endian patricia trees, like Data.IntMap. We first trie on the elements of Data.ByteString and then trie on the big-endian bit representation of those elements. Patricia trees have efficient algorithms for union and other merging operations, but they're also quick for lookups and insertions.
If you are only interested in being able to associate strings to values, then you may prefer the hashmap package which is faster for those only needing a map-like structure. This package is intended for those who need the extra capabilities that a trie-like structure can offer (e.g., structure sharing to reduce memory costs for highly redundant keys, taking the submap of all keys with a given prefix, contextual mapping, extracting the minimum and maximum keys, etc.)
bytestring-trie
The bytestring-trie package provides an efficient implementation of tries mapping ByteString to values. The implementation is based on Okasaki's big-endian patricia trees, à la IntMap. We first trie on the elements of ByteString and then trie on the big-endian bit representation of those elements. Patricia trees have efficient algorithms for union and other merging operations, but they're also quick for lookups and insertions.
If you are only interested in being able to associate individual ByteStrings to values, then you may prefer the hashmap package which is faster for those only needing a map-like structure. This package is intended for those who need the extra capabilities that a trie-like structure can offer (e.g., structure sharing to reduce memory costs for highly redundant keys, taking the submap of all keys with a given prefix, contextual mapping, extracting the minimum and maximum keys, etc.)
Install
This is a simple package and should be easy to install. You should be able to use the standard:
$> cabal install bytestring-trie
Portability
The implementation is quite portable, relying only on a few basic language extensions. The complete list of extensions used by the library is:
- CPP
- MagicHash -- Only if using GHC
- NoImplicitPrelude
The test suite uses a few additional extensions:
- MultiParamTypeClasses
- FlexibleInstances
- FlexibleContexts