crc16 (empty) → 0.1.0

raw patch · 5 files changed

+143/−0 lines, 5 filesdep +HUnitdep +basedep +bytestringbuild-type:Customsetup-changed

Dependencies added: HUnit, base, bytestring

Files

• Data/Digest/CRC16.hs +53/−0
• LICENSE +29/−0
• Setup.hs +10/−0
• Tests.hs +31/−0
• crc16.cabal +20/−0

@@ -0,0 +1,53 @@+{- | crc16 ccitt++   1) MSB first 1021 x^16 + x^12 + x^5 + 1 ++   2) LSB first 8048++-}+module Data.Digest.CRC16 (+     -- * CRC16 method+     crc16_update+    ) where++import Data.Word(Word8,Word16)+import Data.Bits+++-- | crc16 calculation+-- This uses the simple method based on /bit shifting/.+-- See the unittests for an example.+--+crc16_update :: Word16      -- ^ polynomial+             -> Bool        -- ^ inverse bits +             -> Word16      -- ^ initial crc+             -> Word8       -- ^ data byte+             -> Word16      -- ^ new crc+crc16_update poly rev crc b =+    foldl (crc16_update_bit poly) new_crc [1..(bitSize b)]+    where+        new_crc = crc `xor` (shiftL (fromIntegral b' :: Word16) 8 )+        b' = if rev+                then reverse_bits b+                else b+++++crc16_update_bit :: Word16 -> Word16 -> Int -> Word16+crc16_update_bit poly crc _ =+    if (crc .&. 0x8000) /= 0x0000+        then (shiftL crc 1) `xor` poly +        else shiftL crc 1++++-- | Reverse the bits in a byte+--+-- 7..0 becomes 0..7+--+reverse_bits :: Word8 -> Word8+reverse_bits b =+    (shiftL (b .&. 0x01) 7) .|. (shiftL (b .&. 0x02) 5) .|. (shiftL (b .&. 0x04) 3) .|. (shiftL (b .&. 0x08) 1) .|.+    (shiftR (b .&. 0x10) 1) .|. (shiftR (b .&. 0x20) 3) .|. (shiftR (b .&. 0x40) 5) .|. (shiftR (b .&. 0x80) 7)+

@@ -0,0 +1,29 @@+Copyright (c) 2009, Joris Putcuyps+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.++- The names of the copyright holders may not be used to endorse or+promote products derived from this software without specific prior+written permission.++THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS "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 HOLDERS 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 +1,10 @@+import Distribution.Simple+import Data.Digest.CRC16+import Test.HUnit.Text+import Tests++main = +    defaultMainWithHooks ( simpleUserHooks { runTests = test_crc16 } )+    where+        test_crc16 _ _ _ _ = do runTestTT tests+                                return ()

@@ -0,0 +1,31 @@+module Tests where++import Test.HUnit.Base+import Test.HUnit.Text+import Data.Digest.CRC16+import qualified Data.ByteString as B+import Data.Word+++crc16 :: Word16 -> Bool -> Word16 -> [Word8] -> Word16+crc16 poly inverse initial data_string =+    B.foldl (crc16_update poly inverse) initial (B.pack data_string)+++-- | Test functions+--+-- Run with: +-- +-- > import Test.HUnit.Text+-- > runTestTT tests+--+-- Checkout http://zorc.breitbandkatze.de/crc.html+tests :: Test+tests = "Basic" ~: [+             0x29B1 ~=? crc16 0x1021 False 0xffff simple_string+            ,0x89f6 ~=? crc16 0x1021 True 0xffff simple_string+            ,0x31C3 ~=? crc16 0x1021 False 0x0000 simple_string+        ]+        where +            simple_string = [0x31,0x32,0x33,0x34,0x35,0x36,0x37,0x38,0x39] --string "123456789"+

@@ -0,0 +1,20 @@+name:           crc16 +version:        0.1.0+cabal-version:  >= 1.2+build-Type:     Custom+license:        BSD3+license-file:	LICENSE+copyright:      (c) 2009 Joris Putcuyps+author:         Joris Putcuyps+maintainer:     Joris.Putcuyps@gmail.com+bug-reports:    mailto:Joris.Putcuyps@gmail.com+synopsis:       Calculate the crc16-ccitt.+description:    This module provides a method to calculate the crc16-ccitt using the slow bit shift way.+category:       Cryptography+extra-source-files: Tests.hs++Library+    Build-Depends:    base, bytestring, HUnit+    Exposed-modules:  Data.Digest.CRC16+    ghc-options:      -Wall+