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dist | ||
dist-* | ||
cabal-dev | ||
*.o | ||
*.hi | ||
*.chi | ||
*.chs.h | ||
*.dyn_o | ||
*.dyn_hi | ||
.hpc | ||
.hsenv | ||
.cabal-sandbox/ | ||
cabal.sandbox.config | ||
*.prof | ||
*.aux | ||
*.hp | ||
*.eventlog | ||
.stack-work/ | ||
cabal.project.local | ||
cabal.project.local~ | ||
.HTF/ | ||
.ghc.environment.* |
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# Revision history for elias-fano | ||
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## 0 -- YYYY-mm-dd | ||
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* First version. Released on an unsuspecting world. |
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Copyright (c) 2018, Fumiaki Kinoshita | ||
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All rights reserved. | ||
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Redistribution and use in source and binary forms, with or without | ||
modification, are permitted provided that the following conditions are met: | ||
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* Redistributions of source code must retain the above copyright | ||
notice, this list of conditions and the following disclaimer. | ||
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* 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. | ||
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* Neither the name of Fumiaki Kinoshita nor the names of other | ||
contributors may be used to endorse or promote products derived | ||
from this software without specific prior written permission. | ||
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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. | ||
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Copyright 2013 Edward Kmett | ||
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All rights reserved. | ||
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Redistribution and use in source and binary forms, with or without | ||
modification, are permitted provided that the following conditions | ||
are met: | ||
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1. Redistributions of source code must retain the above copyright | ||
notice, this list of conditions and the following disclaimer. | ||
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2. 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. | ||
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THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``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 AUTHORS 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. |
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import Distribution.Simple | ||
main = defaultMain |
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-- Initial elias-fano.cabal generated by cabal init. For further | ||
-- documentation, see http://haskell.org/cabal/users-guide/ | ||
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name: elias-fano | ||
version: 0 | ||
synopsis: Elias-fano encoder | ||
-- description: | ||
homepage: https://github.com/fumieval/elias-fano | ||
license: BSD3 | ||
license-file: LICENSE | ||
author: Fumiaki Kinoshita | ||
maintainer: fumiexcel@gmail.com | ||
-- copyright: | ||
category: Codec | ||
build-type: Simple | ||
extra-source-files: CHANGELOG.md | ||
cabal-version: >=1.10 | ||
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library | ||
exposed-modules: Codec.EliasFano | ||
, Codec.EliasFano.Internal | ||
-- other-modules: | ||
-- other-extensions: | ||
build-depends: base >=4.8 && <4.14, vector, QuickCheck, split | ||
hs-source-dirs: src | ||
ghc-options: -O2 -Wall | ||
default-language: Haskell2010 |
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module Codec.EliasFano (EliasFano(..), unsafeEncode, access, prop_access) where | ||
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import Control.Monad.ST | ||
import Data.Bits | ||
import qualified Data.Vector.Storable as V | ||
import qualified Data.Vector.Storable.Mutable as MV | ||
import Data.Word | ||
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import Codec.EliasFano.Internal | ||
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import qualified Test.QuickCheck as QC | ||
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unsafeEncodeMax :: Int -> V.Vector Int -> EliasFano | ||
unsafeEncodeMax maxValue vec = runST $ do | ||
let counterSize = 1 `unsafeShiftL` ceiling (logBase 2 $ fromIntegral len :: Double) | ||
mcounter <- MV.replicate counterSize 0 | ||
V.forM_ vec $ \v -> MV.unsafeModify mcounter (+1) (v `unsafeShiftR` width) | ||
counter <- V.unsafeFreeze mcounter | ||
let upd (Left i) | ||
| i == len = Skip (Right 0) | ||
| otherwise = Yield width (fromIntegral $ V.unsafeIndex vec i) (Left $! i + 1) | ||
upd (Right i) | ||
| i == counterSize = Done | ||
| otherwise = let n = V.unsafeIndex counter i in Yield (n + 1) (mask n) (Right $! i + 1) | ||
return EliasFano | ||
{ efWidth = width | ||
, efLength = len | ||
, efContent = V.fromList $ build $ BitStream (Left 0) upd | ||
} | ||
where | ||
len = V.length vec | ||
width = max 1 $ ceiling $ logBase 2 (fromIntegral maxValue / fromIntegral len :: Double) | ||
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unsafeEncode :: V.Vector Int -> EliasFano | ||
unsafeEncode vec | ||
| V.null vec = unsafeEncodeMax 1 vec | ||
| otherwise = unsafeEncodeMax (V.last vec + 1) vec | ||
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data EliasFano = EliasFano | ||
{ efWidth :: !Int | ||
, efLength :: !Int | ||
, efContent :: !(V.Vector Word64) | ||
} | ||
deriving Show | ||
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access :: EliasFano -> Int -> Int | ||
access (EliasFano width len vec) i = unsafeShiftL (selectFrom (len * width) vec i - i) width | ||
.|. fromIntegral (readBits vec width (i * width)) | ||
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prop_access :: [QC.NonNegative Int] -> QC.NonNegative Int -> QC.Property | ||
prop_access xs i_ = QC.counterexample (show (base, ef, i)) | ||
$ access ef i == base !! i | ||
where | ||
i = QC.getNonNegative i_ `mod` length base | ||
base = scanl (+) 0 $ map QC.getNonNegative xs | ||
ef = unsafeEncode $ V.fromList base |
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{-# LANGUAGE BangPatterns #-} | ||
{-# LANGUAGE ExistentialQuantification #-} | ||
module Codec.EliasFano.Internal (Step(..) | ||
, BitStream(..) | ||
, mask | ||
, build | ||
, readBits | ||
, selectFrom | ||
) where | ||
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import Control.Exception (assert) | ||
import Data.Bits | ||
import Data.String | ||
import Data.Word (Word64) | ||
import Data.List.Split (chunksOf) | ||
import qualified Data.Vector.Storable as V | ||
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data Step s = Done | ||
| Skip s | ||
| Yield !Int !Word64 s | ||
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data BitStream = forall s. BitStream s (s -> Step s) | ||
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instance Show BitStream where | ||
show (BitStream s0 f) = show (unwords $ chunksOf 8 $ go s0) where | ||
go s = case f s of | ||
Done -> "" | ||
Skip s' -> go s' | ||
Yield width w s' -> [if testBit w i then '1' else '0' | i <- [0..width - 1]] ++ go s' | ||
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instance IsString BitStream where | ||
fromString str = BitStream str go where | ||
go [] = Done | ||
go ('0' : xs) = Yield 1 0 xs | ||
go (_ : xs) = Yield 1 1 xs | ||
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mask :: Int -> Word64 | ||
mask n = unsafeShiftL 1 n - 1 | ||
{-# INLINE mask #-} | ||
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build :: BitStream -> [Word64] | ||
build (BitStream s0 upd) = go s0 zeroBits 0 where | ||
go s !acc !len = case upd s of | ||
Done -> [acc | len > 0] | ||
Skip s' -> go s' acc len | ||
Yield width w s' -> case mask width .&. w of | ||
w' | width + len >= 64 -> (acc .|. unsafeShiftL w' len) | ||
: go s' (unsafeShiftR w' (64 - len)) (len + width - 64) | ||
| otherwise -> go s' (acc .|. unsafeShiftL w' len) (len + width) | ||
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readBits :: V.Vector Word64 -> Int -> Int -> Word64 | ||
readBits vec width pos | ||
| b + width > 64 = unsafeShiftL extra (64 - b) .|. base | ||
| otherwise = base | ||
where | ||
i = unsafeShiftR pos 6 | ||
b = pos .&. 63 | ||
base = (V.unsafeIndex vec i `unsafeShiftR` b) .&. mask width | ||
extra = V.unsafeIndex vec (i + 1) .&. mask (width + b - 64) | ||
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selectFrom :: Int -> V.Vector Word64 -> Int -> Int | ||
selectFrom offset vec = go offset 0 where | ||
go ofs i q | ||
| ofs >= 64 = go (ofs - 64) (i + 1) q | ||
| ofs == 0, popCount v < q = 64 + go ofs (i + 1) (q - popCount v) | ||
| ofs == 0 = selectWord64 v q | ||
| i >= V.length vec - 1 = selectWord64 (v `unsafeShiftR` ofs) q | ||
| popCount v' <= q = 64 + go ofs (i + 1) (q - popCount v') | ||
| otherwise = selectWord64 v' q | ||
where | ||
v = V.unsafeIndex vec i | ||
v' = v `unsafeShiftR` ofs .|. V.unsafeIndex vec (i + 1) `unsafeShiftL` (64 - ofs) | ||
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-- | Convert a word of various bits into a word where each byte contains the count of bits in the corresponding original byte | ||
-- | ||
-- @'popCount' = 'byteSum' . 'byteCounts'@ | ||
byteCounts :: Word64 -> Word64 | ||
byteCounts a = d .&. lsns where | ||
threes = 0x3333333333333333 | ||
as = 0xAAAAAAAAAAAAAAAA | ||
lsbs = 0x0101010101010101 | ||
lsns = 0x0f * lsbs | ||
b = a - shiftR (a .&. as) 1 | ||
c = (b .&. threes) + (shiftR b 2 .&. threes) | ||
d = c + shiftR c 4 | ||
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-- | signed compare byte by byte, returning whether or not the result is less than or equal to | ||
-- the corresponding byte in the other word as the least significant bit of each byte | ||
leq8 :: Word64 -> Word64 -> Word64 | ||
leq8 x y = shiftR (w .&. msbs) 7 where | ||
msbs = 0x8080808080808080 | ||
z = (y .|. msbs) - (x .&. complement msbs) | ||
w = x `xor` y `xor` z | ||
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-- https://github.com/ekmett/succinct/blob/7e884138c2e943f5ca08f56b58b409d08b870ab9/src/Succinct/Internal/Broadword.hs | ||
nonzero8 :: Word64 -> Word64 | ||
nonzero8 x = shiftR ((x .|. ((x .|. msbs) - lsbs)) .&. msbs) 7 where | ||
msbs = 0x8080808080808080 | ||
lsbs = 0x0101010101010101 | ||
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-- https://github.com/ekmett/succinct/blob/7e884138c2e943f5ca08f56b58b409d08b870ab9/src/Succinct/Internal/Broadword.hs | ||
selectWord64 :: Word64 -> Int -> Int | ||
selectWord64 x k = assert (k < popCount x) (place + offset) where | ||
wk = fromIntegral k | ||
lsbs = 0x0101010101010101 | ||
hi = 0xFFFFFFFFFFFFFFF8 | ||
inc = 0x8040201008040201 | ||
sums = byteCounts x * lsbs | ||
steps = wk * lsbs | ||
place = fromIntegral $ shiftR (leq8 sums steps * lsbs) 53 .&. hi | ||
br = wk - (shiftR (shiftL sums 8) place .&. 0xFF) | ||
spread = (shiftR x place .&. 0xFF) * lsbs | ||
bitSums = nonzero8 (spread .&. inc) * lsbs | ||
offset = fromIntegral $ shiftR (leq8 bitSums (br * lsbs) * lsbs) 56 |