bv-embed (empty) → 0.1.0

raw patch · 7 files changed

+136/−0 lines, 7 filesdep +basesetup-changed

Dependencies added: base

Files

• .ghc.environment.x86_64-darwin-8.6.3 +15/−0
• CHANGELOG.md +5/−0
• LICENSE +30/−0
• README.md +1/−0
• Setup.hs +2/−0
• bv-embed.cabal +26/−0
• src/Data/BitVector/Embed.hs +57/−0

@@ -0,0 +1,15 @@+-- This is a GHC environment file written by cabal. This means you can+-- run ghc or ghci and get the environment of the project as a whole.+-- But you still need to use cabal repl $target to get the environment+-- of specific components (libs, exes, tests etc) because each one can+-- have its own source dirs, cpp flags etc.+-- +clear-package-db+global-package-db+package-db /Users/benselfridge/.cabal/store/ghc-8.6.3/package.db+package-db dist-newstyle/packagedb/ghc-8.6.3+package-id bv-embed-0.1.0-inplace+package-id base-4.12.0.0+package-id ghc-prim-0.5.3+package-id rts+package-id integer-gmp-1.0.2.0

@@ -0,0 +1,5 @@+# Revision history for bv-embed++## 0.1.0.0 -- YYYY-mm-dd++* First version. Released on an unsuspecting world.

@@ -0,0 +1,30 @@+Copyright (c) 2019, Ben Selfridge++All rights reserved.++Redistribution and use in source and binary forms, with or without+modification, are permitted provided that the following conditions are met:++    * Redistributions of source code must retain the above copyright+      notice, this list of conditions and the following disclaimer.++    * Redistributions in binary form must reproduce the above+      copyright notice, this list of conditions and the following+      disclaimer in the documentation and/or other materials provided+      with the distribution.++    * Neither the name of Ben Selfridge nor the names of other+      contributors may be used to endorse or promote products derived+      from this software without specific prior written permission.++THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

@@ -0,0 +1,1 @@+bv-embed - Define embeddings of small bit vectors into larger ones

@@ -0,0 +1,2 @@+import Distribution.Simple+main = defaultMain

@@ -0,0 +1,26 @@+cabal-version:       2.4+-- Initial package description 'bv-embed.cabal' generated by 'cabal init'.+--   For further documentation, see http://haskell.org/cabal/users-guide/++name:                bv-embed+version:             0.1.0+synopsis:            Define embeddings of small bit vectors into larger ones+description:         Data structures for defining embeddings of small bit vectors+                     into larger ones. Functions that perform the embedding and+                     extracting.+-- bug-reports:+license:             BSD-3-Clause+license-file:        LICENSE+author:              Ben Selfridge+maintainer:          benselfridge@galois.com+-- copyright:+category:            Data+extra-source-files:  CHANGELOG.md++library+  exposed-modules:   Data.BitVector.Embed+  -- other-modules:+  -- other-extensions:+  build-depends:       base >=4.6 && <5+  hs-source-dirs:      src+  default-language:    Haskell2010

@@ -0,0 +1,57 @@++{-|+Module      : Data.BitVector.Embed+Copyright   : (c) Galois Inc. 2018+License     : BSD-3+Maintainer  : benselfridge@galois.com+Stability   : experimental+Portability : portable++This module exports types and functions for defining how a small bit vector is+embedded into a larger one.++-}++module Data.BitVector.Embed+  ( BitEmbedding+  , fromList+  , bitEmbed+  , bitExtract+  ) where++import qualified Data.Bits as B++-- | Defines a mapping from each bit of a small bit vector into a larger one.+newtype BitEmbedding = BitEmbedding [Int]+  deriving (Eq, Ord, Show)++-- | Construct a `BitEmbedding` from a list, where the length of the list is the same+-- as the width of the "small" bit vector we are embedding into the larger one. The+-- nth element of the list tells us at which bit index in the target to embed bit n+-- of the source.+fromList :: [Int] -> BitEmbedding+fromList = BitEmbedding++-- | Embed a smaller bit vector into a larger one using a `BitEmbedding`.+--+-- >>> bitEmbed (fromList [4,5,7] 7 0)+-- 176+bitEmbed :: (B.Bits src, B.Bits tgt) => BitEmbedding -> src -> tgt -> tgt+bitEmbed (BitEmbedding []) _ tgt = tgt+bitEmbed (BitEmbedding (bit:rst)) src tgt =+  bitEmbed (BitEmbedding rst) (src `B.shiftR` 1) (tgt B..|. bitMask)+  where bitMask = if B.testBit src 0+                  then B.bit bit+                  else B.zeroBits++-- | Extract a smaller bit vector from a larger one using a `BitEmbedding`.+--+-- >>> bitExtract (fromList [4,5,7] 7 0) 176+-- 7+bitExtract :: (B.Bits src, B.Bits tgt) => BitEmbedding -> tgt -> src+bitExtract (BitEmbedding []) _ = B.zeroBits+bitExtract (BitEmbedding (bit:rst)) tgt =+  (bitExtract (BitEmbedding rst) tgt `B.shiftL` 1) B..|. bitMask+  where bitMask = if B.testBit tgt bit+                  then B.bit 0+                  else B.zeroBits