attoparsec-varword (empty) → 0.1.0.0
raw patch · 8 files changed
+377/−0 lines, 8 filesdep +QuickCheckdep +attoparsecdep +attoparsec-varwordsetup-changed
Dependencies added: QuickCheck, attoparsec, attoparsec-varword, base, bytestring, bytestring-builder-varword, hspec
Files
- LICENSE +165/−0
- README.md +5/−0
- Setup.hs +2/−0
- attoparsec-varword.cabal +48/−0
- src/Data/Attoparsec/VarWord.hs +79/−0
- src/Data/Attoparsec/VarWord/Internal.hs +40/−0
- test/Data/Attoparsec/VarWordSpec.hs +37/−0
- test/Spec.hs +1/−0
+ LICENSE view
@@ -0,0 +1,165 @@+ GNU LESSER GENERAL PUBLIC LICENSE+ Version 3, 29 June 2007++ Copyright (C) 2007 Free Software Foundation, Inc. <https://fsf.org/>+ Everyone is permitted to copy and distribute verbatim copies+ of this license document, but changing it is not allowed.+++ This version of the GNU Lesser General Public License incorporates+the terms and conditions of version 3 of the GNU General Public+License, supplemented by the additional permissions listed below.++ 0. Additional Definitions.++ As used herein, "this License" refers to version 3 of the GNU Lesser+General Public License, and the "GNU GPL" refers to version 3 of the GNU+General Public License.++ "The Library" refers to a covered work governed by this License,+other than an Application or a Combined Work as defined below.++ An "Application" is any work that makes use of an interface provided+by the Library, but which is not otherwise based on the Library.+Defining a subclass of a class defined by the Library is deemed a mode+of using an interface provided by the Library.++ A "Combined Work" is a work produced by combining or linking an+Application with the Library. The particular version of the Library+with which the Combined Work was made is also called the "Linked+Version".++ The "Minimal Corresponding Source" for a Combined Work means the+Corresponding Source for the Combined Work, excluding any source code+for portions of the Combined Work that, considered in isolation, are+based on the Application, and not on the Linked Version.++ The "Corresponding Application Code" for a Combined Work means the+object code and/or source code for the Application, including any data+and utility programs needed for reproducing the Combined Work from the+Application, but excluding the System Libraries of the Combined Work.++ 1. Exception to Section 3 of the GNU GPL.++ You may convey a covered work under sections 3 and 4 of this License+without being bound by section 3 of the GNU GPL.++ 2. Conveying Modified Versions.++ If you modify a copy of the Library, and, in your modifications, a+facility refers to a function or data to be supplied by an Application+that uses the facility (other than as an argument passed when the+facility is invoked), then you may convey a copy of the modified+version:++ a) under this License, provided that you make a good faith effort to+ ensure that, in the event an Application does not supply the+ function or data, the facility still operates, and performs+ whatever part of its purpose remains meaningful, or++ b) under the GNU GPL, with none of the additional permissions of+ this License applicable to that copy.++ 3. Object Code Incorporating Material from Library Header Files.++ The object code form of an Application may incorporate material from+a header file that is part of the Library. You may convey such object+code under terms of your choice, provided that, if the incorporated+material is not limited to numerical parameters, data structure+layouts and accessors, or small macros, inline functions and templates+(ten or fewer lines in length), you do both of the following:++ a) Give prominent notice with each copy of the object code that the+ Library is used in it and that the Library and its use are+ covered by this License.++ b) Accompany the object code with a copy of the GNU GPL and this license+ document.++ 4. Combined Works.++ You may convey a Combined Work under terms of your choice that,+taken together, effectively do not restrict modification of the+portions of the Library contained in the Combined Work and reverse+engineering for debugging such modifications, if you also do each of+the following:++ a) Give prominent notice with each copy of the Combined Work that+ the Library is used in it and that the Library and its use are+ covered by this License.++ b) Accompany the Combined Work with a copy of the GNU GPL and this license+ document.++ c) For a Combined Work that displays copyright notices during+ execution, include the copyright notice for the Library among+ these notices, as well as a reference directing the user to the+ copies of the GNU GPL and this license document.++ d) Do one of the following:++ 0) Convey the Minimal Corresponding Source under the terms of this+ License, and the Corresponding Application Code in a form+ suitable for, and under terms that permit, the user to+ recombine or relink the Application with a modified version of+ the Linked Version to produce a modified Combined Work, in the+ manner specified by section 6 of the GNU GPL for conveying+ Corresponding Source.++ 1) Use a suitable shared library mechanism for linking with the+ Library. A suitable mechanism is one that (a) uses at run time+ a copy of the Library already present on the user's computer+ system, and (b) will operate properly with a modified version+ of the Library that is interface-compatible with the Linked+ Version.++ e) Provide Installation Information, but only if you would otherwise+ be required to provide such information under section 6 of the+ GNU GPL, and only to the extent that such information is+ necessary to install and execute a modified version of the+ Combined Work produced by recombining or relinking the+ Application with a modified version of the Linked Version. (If+ you use option 4d0, the Installation Information must accompany+ the Minimal Corresponding Source and Corresponding Application+ Code. If you use option 4d1, you must provide the Installation+ Information in the manner specified by section 6 of the GNU GPL+ for conveying Corresponding Source.)++ 5. Combined Libraries.++ You may place library facilities that are a work based on the+Library side by side in a single library together with other library+facilities that are not Applications and are not covered by this+License, and convey such a combined library under terms of your+choice, if you do both of the following:++ a) Accompany the combined library with a copy of the same work based+ on the Library, uncombined with any other library facilities,+ conveyed under the terms of this License.++ b) Give prominent notice with the combined library that part of it+ is a work based on the Library, and explaining where to find the+ accompanying uncombined form of the same work.++ 6. Revised Versions of the GNU Lesser General Public License.++ The Free Software Foundation may publish revised and/or new versions+of the GNU Lesser General Public License from time to time. Such new+versions will be similar in spirit to the present version, but may+differ in detail to address new problems or concerns.++ Each version is given a distinguishing version number. If the+Library as you received it specifies that a certain numbered version+of the GNU Lesser General Public License "or any later version"+applies to it, you have the option of following the terms and+conditions either of that published version or of any later version+published by the Free Software Foundation. If the Library as you+received it does not specify a version number of the GNU Lesser+General Public License, you may choose any version of the GNU Lesser+General Public License ever published by the Free Software Foundation.++ If the Library as you received it specifies that a proxy can decide+whether future versions of the GNU Lesser General Public License shall+apply, that proxy's public statement of acceptance of any version is+permanent authorization for you to choose that version for the+Library.
+ README.md view
@@ -0,0 +1,5 @@+Variable-length integer decoding+================================++This package provides a collection of `Attoparsec` `Parser`s to decode integers+encoded in several variable-length formats.
+ Setup.hs view
@@ -0,0 +1,2 @@+import Distribution.Simple+main = defaultMain
+ attoparsec-varword.cabal view
@@ -0,0 +1,48 @@+name: attoparsec-varword+version: 0.1.0.0+synopsis: Variable-length integer decoding for Attoparsec+description:+ A collection of 'Data.Attoparsec.Parser's that decode integer types from+ compact, variable-length representations.+homepage: https://github.com/concert/hs-varword#readme+bug-reports: https://github.com/concert/hs-varword/issues+stability: Experimental+license: LGPL-3+license-file: LICENSE+author: Paul Weaver+maintainer: paul@concertdaw.co.uk+copyright: 2018 Concert Audio Technologies Ltd+category: Data+build-type: Simple+extra-source-files: README.md+cabal-version: >=1.10++source-repository head+ type: git+ location: https://github.com/githubuser/attoparsec-varword++library+ hs-source-dirs: src+ ghc-options: -Wall+ default-extensions: BinaryLiterals+ exposed-modules: Data.Attoparsec.VarWord+ , Data.Attoparsec.VarWord.Internal+ build-depends: base >= 4.7 && < 5+ , attoparsec >= 0.10 && < 0.14+ default-language: Haskell2010++test-suite attoparsec-varword-test+ type: exitcode-stdio-1.0+ main-is: Spec.hs+ hs-source-dirs: test+ ghc-options: -threaded -rtsopts -with-rtsopts=-N -Wall+ default-extensions: BinaryLiterals+ build-depends: base >= 4.7 && < 5+ , attoparsec-varword+ , attoparsec >= 0.10 && < 0.14+ , bytestring >= 0.9 && < 0.11+ , bytestring-builder-varword >= 0.1 && < 0.2+ , hspec >= 2.4.3 && < 2.5.0+ , QuickCheck >= 2.7 && < 2.11.4+ other-modules: Data.Attoparsec.VarWordSpec+ default-language: Haskell2010
+ src/Data/Attoparsec/VarWord.hs view
@@ -0,0 +1,79 @@+{- |+Description: "Attoparsec" 'Parser's for varible-length-encoded integers++We define "Attoparsec" 'Parser's for several different variable-length integer+encoding schemes. These schemes are useful for transmitting numerical data+in a more compact form than would be available from simple big- or little-endian+encoding of the values.+-}++module Data.Attoparsec.VarWord+ ( varWordBe, denseVarWordBe+ , varWordLe+ ) where++import Data.Attoparsec.ByteString (Parser)+import Data.Bits (Bits)++import Data.Attoparsec.VarWord.Internal (varWordBe', varWordLe')+++-- | Decode a big-endian (most significant byte first), variable-length encoded+-- value.+--+-- > +-- Keep reading+-- > | +-- Keep reading+-- > | | +-- Stop+-- > v v v+-- > 10000001 10010000 00100000+-- > |<--->| |<--->| |<--->|+-- > Data(A) Data(B) Data(C)+-- >+-- > == 1 0010000 0100000 == 18464+-- > (A) (B) (C)+--+-- >>> parseOnly varWordBe "\129\144\32"+-- Right 18464+--+varWordBe :: (Bits a, Integral a) => Parser a+varWordBe = varWordBe' 0 0++-- | Decode a big-endian (least significant byte first), variable length+-- encoded value where the continuation byte is used to carry data also.+--+-- > +-- Keep reading+-- > | +-- Keep reading+-- > | | +-- Stop+-- > v v v+-- > 10000001 10010000 00100000+-- > |<--->| |<--->| |<--->|+-- > Data(A) Data(B) Data(C)+-- >+-- > == 10 0010001 0100000 == 34976+-- > (A+1) (B+1) (C)+--+-- >>> parseOnly denseVarWordBeP "\129\144\32"+-- Right 34976+--+denseVarWordBe :: (Bits a, Integral a) => Parser a+denseVarWordBe = varWordBe' 1 0++-- | Decode a little-endian (least significant byte first), variable length+-- encoded value.+--+-- > +-- Keep reading+-- > | +-- Keep reading+-- > | | +-- Stop+-- > v v v+-- > 10000001 10010000 00100000+-- > |<--->| |<--->| |<--->|+-- > Data(A) Data(B) Data(C)+-- >+-- > == 100000 0010000 0000001 == 526337+-- > (C) (B) (A)+--+-- >>> parseOnly varWordLe "\129\144\32"+-- Right 526337+--+varWordLe :: (Bits a, Integral a) => Parser a+varWordLe = varWordLe' 0 0
+ src/Data/Attoparsec/VarWord/Internal.hs view
@@ -0,0 +1,40 @@+{- |+Internal implementation of variable-length decoding. This API is not guaranteed+to be stable.+-}+module Data.Attoparsec.VarWord.Internal+ ( varWordBe', varWordLe'+ ) where++import Data.Attoparsec.ByteString (Parser, anyWord8)+import Data.Bits (Bits, shiftL, testBit, (.&.), (.|.))+import Data.Word+++msb :: Word8 -> Bool+msb = flip testBit 7++lsbs :: Word8 -> Word8+lsbs = (.&. 0b01111111)+++-- | Internal implementation of big-endian variable-length decoding, exposing+-- the accumulator and how much to increment each continuation chunk.+varWordBe' :: (Bits a, Integral a) => a -> a -> Parser a+varWordBe' contInc acc = do+ byte <- anyWord8+ let acc' = shiftL acc 7 .|. fromIntegral (lsbs byte)+ if msb byte+ then varWordBe' contInc (acc' + contInc)+ else return acc'+++-- | Internal implementation of little-endian variable-length decoding, exposing+-- the accumulator and the shift for each chunk.+varWordLe' :: (Bits a, Integral a) => Int -> a -> Parser a+varWordLe' shiftBy acc = do+ byte <- anyWord8+ let acc' = acc .|. shiftL (fromIntegral $ lsbs byte) shiftBy+ if msb byte+ then varWordLe' (shiftBy + 7) acc'+ else return acc'
+ test/Data/Attoparsec/VarWordSpec.hs view
@@ -0,0 +1,37 @@+module Data.Attoparsec.VarWordSpec where++import Test.Hspec+import Test.QuickCheck+import Data.Attoparsec.ByteString (Parser, parseOnly)+import qualified Data.ByteString as BS+import qualified Data.ByteString.Lazy as LBS+import Data.Word++import Data.ByteString.Builder (Builder)+import qualified Data.ByteString.Builder as Builder+import qualified Data.ByteString.Builder.VarWord as Builder++import Data.Attoparsec.VarWord (varWordBe, denseVarWordBe, varWordLe)++spec :: Spec+spec = do+ varWordSpec "Big-endian chunked number parser"+ varWordBe Builder.varWordBe 18464+ varWordSpec "Big-endian dense chunked number parser"+ denseVarWordBe Builder.denseVarWordBe 34976+ varWordSpec "Little-endian chunked number parser"+ varWordLe Builder.varWordLe 526337+++varWordSpec :: String -> Parser Word32 -> (Word32 -> Builder) -> Word32 -> Spec+varWordSpec s p b expected = describe s $ do+ it "should parse a known bytestring" $ do+ parseOnly p (BS.pack [0b10000001, 0b10010000, 0b00100000])+ `shouldBe` Right expected+ it "should parse any valid single byte" $ forAll (choose (0, 127)) $ \word8 ->+ parseOnly p (BS.singleton word8) `shouldBe` Right (fromIntegral word8)+ it "should roundtrip any valid bytestring" $ property $ \word32 ->+ let+ encoded = LBS.toStrict $ Builder.toLazyByteString $ b word32+ in+ parseOnly p encoded `shouldBe` Right word32
+ test/Spec.hs view
@@ -0,0 +1,1 @@+{-# OPTIONS_GHC -F -pgmF hspec-discover #-}