Initial import of version 1.0.0

CHANGES

@@ -0,0 +1,4 @@
+= Version 1.0.0, 2010-08-15 =
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+* Separating Hashable class to its own package
+from hashmap 1.0.0.3.

Data/Hashable.hs

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+{-# LANGUAGE ForeignFunctionInterface #-}
+
+-----------------------------------------------------------------------------
+-- |
+-- Module      :  Data.Hash
+-- Copyright   :  (c) Milan Straka 2010
+-- License     :  BSD-style
+-- Maintainer  :  fox@ucw.cz
+-- Stability   :  provisional
+-- Portability :  portable
+--
+-- 'Hashable' class for hashable types, with instances for basic types. The only
+-- function of this class is
+--
+-- @
+--   'hash' :: Hashable h => h -> Int
+-- @
+--
+-- The 'hash' function should be as collision-free as possible, the probability
+-- of @'hash' a == 'hash' b@ should ideally be 1 over the number of representable
+-- values in an 'Int'.
+--
+-- Returning an 'Int' is a result of the 'Data.IntMap.IntMap' using 'Int' as
+-- a key, as inserting the hash values to the 'Data.IntMap.IntMap' was the
+-- purpose of creating this class.
+-----------------------------------------------------------------------------
+
+module Data.Hashable ( Hashable(..)
+                     , combine
+                     ) where
+
+import Data.Bits
+import Data.Int
+import Data.Word
+import Data.List (foldl')
+import qualified Data.ByteString as B
+import qualified Data.ByteString.Internal as BInt
+import qualified Data.ByteString.Unsafe as BInt
+import qualified Data.ByteString.Lazy as BL
+import qualified Data.ByteString.Lazy.Internal as BLInt
+import Foreign.C
+
+-- | The class containing a function 'hash' which computes the hash values of
+-- given value.
+class Hashable a where
+    -- | The computed 'hash' value should be as collision-free as possible, the
+    -- probability of @'hash' a == 'hash' b@ should ideally be 1 over the
+    -- number of representable values in an 'Int'.
+    hash :: a -> Int
+
+-- | Combines two given hash values.
+combine :: Int -> Int -> Int
+combine h1 h2 = (h1 + h1 `shiftL` 5) `xor` h2
+
+hashAndCombine :: Hashable h => Int -> h -> Int
+hashAndCombine acc h = acc `combine` hash h
+
+instance Hashable () where hash _ = 0
+
+instance Hashable Bool where hash x = case x of { True -> 1; False -> 0 }
+
+instance Hashable Int where hash = id
+instance Hashable Int8 where hash = fromIntegral
+instance Hashable Int16 where hash = fromIntegral
+instance Hashable Int32 where hash = fromIntegral
+instance Hashable Int64 where hash = fromIntegral
+
+instance Hashable Word where hash = fromIntegral
+instance Hashable Word8 where hash = fromIntegral
+instance Hashable Word16 where hash = fromIntegral
+instance Hashable Word32 where hash = fromIntegral
+instance Hashable Word64 where hash = fromIntegral
+
+instance Hashable Char where hash = fromEnum
+
+instance Hashable a => Hashable (Maybe a) where
+    hash Nothing = 0
+    hash (Just a) = 42 `combine` hash a
+
+instance (Hashable a1, Hashable a2) => Hashable (a1, a2) where
+    hash (a1, a2) = hash a1 `combine` hash a2
+
+instance (Hashable a1, Hashable a2, Hashable a3) => Hashable (a1, a2, a3) where
+    hash (a1, a2, a3) = hash a1 `combine` hash a2 `combine` hash a3
+
+instance (Hashable a1, Hashable a2, Hashable a3, Hashable a4) => Hashable (a1, a2, a3, a4) where
+    hash (a1, a2, a3, a4) = hash a1 `combine` hash a2 `combine` hash a3 `combine` hash a4
+
+instance (Hashable a1, Hashable a2, Hashable a3, Hashable a4, Hashable a5)
+      => Hashable (a1, a2, a3, a4, a5) where
+    hash (a1, a2, a3, a4, a5) =
+      hash a1 `combine` hash a2 `combine` hash a3 `combine` hash a4 `combine` hash a5
+
+instance (Hashable a1, Hashable a2, Hashable a3, Hashable a4, Hashable a5, Hashable a6)
+      => Hashable (a1, a2, a3, a4, a5, a6) where
+    hash (a1, a2, a3, a4, a5, a6) =
+      hash a1 `combine` hash a2 `combine` hash a3 `combine` hash a4 `combine` hash a5 `combine` hash a6
+
+instance (Hashable a1, Hashable a2, Hashable a3, Hashable a4, Hashable a5, Hashable a6, Hashable a7)
+      => Hashable (a1, a2, a3, a4, a5, a6, a7) where
+    hash (a1, a2, a3, a4, a5, a6, a7) =
+      hash a1 `combine` hash a2 `combine` hash a3 `combine` hash a4 `combine` hash a5 `combine` hash a6 `combine` hash a7
+
+instance Hashable a => Hashable [a] where
+    {-# SPECIALIZE instance Hashable [Char] #-}
+    hash = foldl' hashAndCombine 0
+
+foreign import ccall unsafe hashByteString :: CString -> CInt -> IO CInt
+instance Hashable B.ByteString where
+    hash bstr = fromIntegral $ BInt.inlinePerformIO $ BInt.unsafeUseAsCStringLen bstr $
+                  \(str, len) -> hashByteString str (fromIntegral len)
+
+instance Hashable BL.ByteString where hash = BLInt.foldlChunks hashAndCombine 0

LICENSE

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+Copyright Milan Straka 2010
+
+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 Milan Straka 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.

Setup.hs

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+#!/usr/bin/env runhaskell
+import Distribution.Simple
+main = defaultMain

hashable.cabal

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+Name:                hashable
+Version:             1.0.0
+Synopsis:            Class Hashable providing a hash method.
+Description:         This package provides a class 'Hashable', which contains
+                     one method @'hash' :: 'Hashable' a => a -> 'Int'@, which
+                     returns the hash of the given element.
+                     .
+                     The instances for various integral types, 'String' and 'ByteString'
+                     are provided.
+Homepage:            http://fox.auryn.cz/darcs/hashable
+License:             BSD3
+License-file:        LICENSE
+Author:              Milan Straka
+Maintainer:          fox@ucw.cz
+Stability:           Provisional
+Category:            Data
+Build-type:          Simple
+Cabal-version:       >=1.2
+Extra-source-files:  CHANGES
+
+
+Library
+  Exposed-modules:   Data.Hashable
+  Build-depends:     base >= 4.0 && < 5,
+                     bytestring >= 0.9
+
+  C-sources:         src/hashByteString.c

src/hashByteString.c

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+int hashByteString(const char* str, int len) {
+  int hash = 0;
+
+  while (len--) {
+    hash = (hash * 33) ^ *str++;
+  }
+
+  return hash;
+}