Network.Haskoin.Util

This module defines various utility functions used across the Network.Haskoin modules.

ByteString helpers

bsToInteger :: ByteString -> Integer

Decode a big endian Integer from a bytestring.

integerToBS :: Integer -> ByteString

Encode an Integer to a bytestring as big endian

encodeHex :: ByteString -> ByteString

decodeHex :: ByteString -> Maybe ByteString

Decode hexadecimal ByteString. This function can fail if the string contains invalid hexadecimal (0-9, a-f, A-F) characters

Data.Binary helpers

encode' :: Binary a => a -> ByteString

Strict version of encode

decode' :: Binary a => ByteString -> a

Strict version of decode

runPut' :: Put -> ByteString

Strict version of runPut

runGet' :: Binary a => Get a -> ByteString -> a

Strict version of runGet

decodeOrFail' :: Binary a => ByteString -> Either (ByteString, ByteOffset, String) (ByteString, ByteOffset, a)

Strict version of decodeOrFail

runGetOrFail' :: Get a -> ByteString -> Either (ByteString, ByteOffset, String) (ByteString, ByteOffset, a)

Strict version of runGetOrFail

fromDecode

Arguments

:: Binary a

=> ByteString

The bytestring to decode

-> b

Default value to return when decoding fails

-> (a -> b)

Function to apply when decoding succeeds

-> b

Final result

Try to decode a Binary value. If decoding succeeds, apply the function to the result. Otherwise, return the default value.

fromRunGet

Arguments

:: Binary a

=> Get a

The Get monad to run

-> ByteString

The bytestring to decode

-> b

Default value to return when decoding fails

-> (a -> b)

Function to apply when decoding succeeds

-> b

Final result

Try to run a Get monad. If decoding succeeds, apply a function to the result. Otherwise, return the default value.

decodeToEither :: Binary a => ByteString -> Either String a

Decode a Binary value. A Right value is returned with the result upon success. Otherwise a Left value with the error message is returned.

decodeToMaybe :: Binary a => ByteString -> Maybe a

Decode a Binary value. A Just value is returned with the result upon success. Otherwise, Nothing is returned.

isolate :: Binary a => Int -> Get a -> Get a

Isolate a Get monad for the next Int bytes. Only the next Int bytes of the input ByteString will be available for the Get monad to consume. This function will fail if the Get monad fails or some of the input is not consumed.

Maybe and Either monad helpers

isLeft :: Either a b -> Bool

Returns True if the Either value is Left

isRight :: Either a b -> Bool

Returns True if the Either value is Right

fromRight :: Either a b -> b

Extract the Right value from an Either value. Fails if the value is Left

fromLeft :: Either a b -> a

Extract the Left value from an Either value. Fails if the value is Right

eitherToMaybe :: Either a b -> Maybe b

Transforms an Either value into a Maybe value. Right is mapped to Just and Left is mapped to Nothing. The value inside Left is lost.

maybeToEither :: b -> Maybe a -> Either b a

Transforms a Maybe value into an Either value. Just is mapped to Right and Nothing is mapped to Left. You also pass in an error value in case Left is returned.

liftEither :: Monad m => Either b a -> EitherT b m a

Lift a Either computation into the EitherT monad

liftMaybe :: Monad m => b -> Maybe a -> EitherT b m a

Lift a Maybe computation into the EitherT monad

Various helpers

updateIndex

Arguments

:: Int

The index of the element to change

-> [a]

The list of elements

-> (a -> a)

The function to apply

-> [a]

The result with one element changed

Applies a function to only one element of a list defined by its index. If the index is out of the bounds of the list, the original list is returned.

matchTemplate

Arguments

:: [a]

The input list

-> [b]

The list to serve as a template

-> (a -> b -> Bool)

The comparison function

-> [Maybe a]

Results of the template matching

Use the list [b] as a template and try to match the elements of [a] against it. For each element of [b] return the (first) matching element of [a], or Nothing. Output list has same size as [b] and contains results in same order. Elements of [a] can only appear once.

Triples

fst3 :: (a, b, c) -> a

Returns the first value of a triple.

snd3 :: (a, b, c) -> b

Returns the second value of a triple.

lst3 :: (a, b, c) -> c

Returns the last value of a triple.

MonadState

modify' :: MonadState s m => (s -> s) -> m ()

Strict evaluation of the new state

JSON Utilities

dropFieldLabel :: Int -> Options

dropSumLabels :: Int -> Int -> String -> Options