-- | -- Module : Data.ASN1.Stream -- License : BSD-style -- Maintainer : Vincent Hanquez <vincent@snarc.org> -- Stability : experimental -- Portability : unknown -- module Data.ASN1.Stream ( ASN1Repr , getConstructedEnd , getConstructedEndRepr ) where import Data.ASN1.Types import Data.ASN1.Types.Lowlevel {- associate a list of asn1 event with an ASN1 type. - it's sometimes required to know the exact byte sequence leading to an ASN1 type: - eg: cryptographic signature -} type ASN1Repr = (ASN1, [ASN1Event]) getConstructedEnd :: Int -> [ASN1] -> ([ASN1],[ASN1]) getConstructedEnd _ xs@[] = (xs, []) getConstructedEnd i ((x@(Start _)):xs) = let (yz, zs) = getConstructedEnd (i+1) xs in (x:yz,zs) getConstructedEnd i ((x@(End _)):xs) | i == 0 = ([], xs) | otherwise = let (ys, zs) = getConstructedEnd (i-1) xs in (x:ys,zs) getConstructedEnd i (x:xs) = let (ys, zs) = getConstructedEnd i xs in (x:ys,zs) getConstructedEndRepr :: [ASN1Repr] -> ([ASN1Repr],[ASN1Repr]) getConstructedEndRepr = g where g [] = ([], []) g (x@(Start _,_):xs) = let (ys, zs) = getEnd 1 xs in (x:ys, zs) g (x:xs) = ([x],xs) getEnd :: Int -> [ASN1Repr] -> ([ASN1Repr],[ASN1Repr]) getEnd _ [] = ([], []) getEnd 0 xs = ([], xs) getEnd i ((x@(Start _, _)):xs) = let (ys, zs) = getEnd (i+1) xs in (x:ys,zs) getEnd i ((x@(End _, _)):xs) = let (ys, zs) = getEnd (i-1) xs in (x:ys,zs) getEnd i (x:xs) = let (ys, zs) = getEnd i xs in (x:ys,zs)