1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
|
-- |
-- Module : Data.ByteArray.Pack.Internal
-- License : BSD-Style
-- Copyright : Copyright © 2014 Nicolas DI PRIMA
--
-- Maintainer : Vincent Hanquez <vincent@snarc.org>
-- Stability : experimental
-- Portability : unknown
--
module Data.ByteArray.Pack.Internal
( Result(..)
, Packer(..)
, actionPacker
, actionPackerWithRemain
) where
import Foreign.Ptr (Ptr)
import Data.ByteArray.MemView
import Data.Memory.Internal.Imports
-- | Packing result:
--
-- * PackerMore: the next state of Packing with an arbitrary value
-- * PackerFail: an error happened
data Result a =
PackerMore a MemView
| PackerFail String
deriving (Show)
-- | Simple ByteArray Packer
newtype Packer a = Packer { runPacker_ :: MemView -> IO (Result a) }
instance Functor Packer where
fmap = fmapPacker
instance Applicative Packer where
pure = returnPacker
(<*>) = appendPacker
instance Monad Packer where
return = pure
(>>=) = bindPacker
fmapPacker :: (a -> b) -> Packer a -> Packer b
fmapPacker f p = Packer $ \cache -> do
rv <- runPacker_ p cache
return $ case rv of
PackerMore v cache' -> PackerMore (f v) cache'
PackerFail err -> PackerFail err
{-# INLINE fmapPacker #-}
returnPacker :: a -> Packer a
returnPacker v = Packer $ \cache -> return $ PackerMore v cache
{-# INLINE returnPacker #-}
bindPacker :: Packer a -> (a -> Packer b) -> Packer b
bindPacker p fp = Packer $ \cache -> do
rv <- runPacker_ p cache
case rv of
PackerMore v cache' -> runPacker_ (fp v) cache'
PackerFail err -> return $ PackerFail err
{-# INLINE bindPacker #-}
appendPacker :: Packer (a -> b) -> Packer a -> Packer b
appendPacker p1f p2 = p1f >>= \p1 -> p2 >>= \v -> return (p1 v)
{-# INLINE appendPacker #-}
-- | run a sized action
actionPacker :: Int -> (Ptr Word8 -> IO a) -> Packer a
actionPacker s action = Packer $ \m@(MemView ptr size) ->
case compare size s of
LT -> return $ PackerFail "Not enough space in destination"
_ -> do
v <- action ptr
return $ PackerMore v (m `memViewPlus` s)
{-# INLINE actionPacker #-}
-- | run a sized action
actionPackerWithRemain :: Int -> (Ptr Word8 -> Int -> IO (Int, a)) -> Packer a
actionPackerWithRemain s action = Packer $ \m@(MemView ptr size) ->
case compare size s of
LT -> return $ PackerFail "Not enough space in destination"
_ -> do
(remain, v) <- action ptr size
return $ if remain > s
then PackerFail "remaining bytes higher than the destination's size"
else PackerMore v (m `memViewPlus` (s+remain))
{-# INLINE actionPackerWithRemain #-}
|
