commit 4d4573133f9c4804c728b55773fa9ce4a04ae1dd
parent e64ee423c47e5cf259b4f80d8e9124e39f16f190
Author: Jared Tobin <jared@jtobin.io>
Date: Sun, 25 Jan 2026 15:59:56 +0400
Merge impl/codec: parsing and rendering
Adds lib/Lightning/Protocol/BOLT9/Codec.hs with:
- parse/render for FeatureVector ByteString conversion
- setBit/clearBit/testBit convenience wrappers
- setFeature/hasFeature for feature-level operations
- listFeatures to enumerate set features
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
Diffstat:
3 files changed, 120 insertions(+), 0 deletions(-)
diff --git a/lib/Lightning/Protocol/BOLT9.hs b/lib/Lightning/Protocol/BOLT9.hs
@@ -47,7 +47,22 @@ module Lightning.Protocol.BOLT9 (
, featureByBit
, featureByName
, knownFeatures
+
+ -- * Parsing and rendering
+ , parse
+ , render
+
+ -- * Codec bit operations
+ , Codec.setBit
+ , Codec.clearBit
+ , Codec.testBit
+
+ -- * Codec feature operations
+ , setFeature
+ , hasFeature
+ , listFeatures
) where
+import Lightning.Protocol.BOLT9.Codec as Codec
import Lightning.Protocol.BOLT9.Features
import Lightning.Protocol.BOLT9.Types as FV
diff --git a/lib/Lightning/Protocol/BOLT9/Codec.hs b/lib/Lightning/Protocol/BOLT9/Codec.hs
@@ -0,0 +1,104 @@
+{-# OPTIONS_HADDOCK prune #-}
+{-# LANGUAGE BangPatterns #-}
+
+-- |
+-- Module: Lightning.Protocol.BOLT9.Codec
+-- Copyright: (c) 2025 Jared Tobin
+-- License: MIT
+-- Maintainer: Jared Tobin <jared@ppad.tech>
+--
+-- Parsing and rendering for BOLT #9 feature vectors.
+
+module Lightning.Protocol.BOLT9.Codec (
+ -- * Parsing and rendering
+ parse
+ , render
+
+ -- * Bit operations
+ , setBit
+ , clearBit
+ , testBit
+
+ -- * Feature operations
+ , setFeature
+ , hasFeature
+ , listFeatures
+ ) where
+
+import Data.ByteString (ByteString)
+import qualified Data.ByteString as BS
+import Data.Word (Word16)
+import Lightning.Protocol.BOLT9.Features
+import Lightning.Protocol.BOLT9.Types
+
+-- Parsing and rendering ------------------------------------------------------
+
+-- | Parse a ByteString into a FeatureVector.
+--
+-- Alias for 'fromByteString'.
+parse :: ByteString -> FeatureVector
+parse = fromByteString
+{-# INLINE parse #-}
+
+-- | Render a FeatureVector to a ByteString, trimming leading zero bytes
+-- for compact encoding.
+render :: FeatureVector -> ByteString
+render = BS.dropWhile (== 0) . unFeatureVector
+{-# INLINE render #-}
+
+-- Bit operations -------------------------------------------------------------
+
+-- | Set a bit by raw index.
+setBit :: Word16 -> FeatureVector -> FeatureVector
+setBit !idx = set (bitIndex idx)
+{-# INLINE setBit #-}
+
+-- | Clear a bit by raw index.
+clearBit :: Word16 -> FeatureVector -> FeatureVector
+clearBit !idx = clear (bitIndex idx)
+{-# INLINE clearBit #-}
+
+-- | Test if a bit is set.
+testBit :: Word16 -> FeatureVector -> Bool
+testBit !idx = member (bitIndex idx)
+{-# INLINE testBit #-}
+
+-- Feature operations ---------------------------------------------------------
+
+-- | Set or clear a feature's bit.
+--
+-- If the Bool is True, sets the required (even) bit.
+-- If the Bool is False, sets the optional (odd) bit.
+setFeature :: Feature -> Bool -> FeatureVector -> FeatureVector
+setFeature !f !required = setBit targetBit
+ where
+ !baseBit = featureBaseBit f
+ !targetBit = if required then baseBit else baseBit + 1
+{-# INLINE setFeature #-}
+
+-- | Check if a feature is set in the vector.
+--
+-- Returns:
+--
+-- * @Just True@ if the required (even) bit is set
+-- * @Just False@ if the optional (odd) bit is set (and required is not)
+-- * @Nothing@ if neither bit is set
+hasFeature :: Feature -> FeatureVector -> Maybe Bool
+hasFeature !f !fv
+ | testBit baseBit fv = Just True -- required
+ | testBit (baseBit + 1) fv = Just False -- optional
+ | otherwise = Nothing
+ where
+ !baseBit = featureBaseBit f
+{-# INLINE hasFeature #-}
+
+-- | List all known features that are set in the vector.
+--
+-- Returns pairs of (Feature, Bool) where the Bool indicates if the
+-- required (even) bit is set (True) or the optional (odd) bit (False).
+listFeatures :: FeatureVector -> [(Feature, Bool)]
+listFeatures !fv = foldr check [] knownFeatures
+ where
+ check !f !acc = case hasFeature f fv of
+ Just isReq -> (f, isReq) : acc
+ Nothing -> acc
diff --git a/ppad-bolt9.cabal b/ppad-bolt9.cabal
@@ -25,6 +25,7 @@ library
-Wall
exposed-modules:
Lightning.Protocol.BOLT9
+ Lightning.Protocol.BOLT9.Codec
Lightning.Protocol.BOLT9.Features
Lightning.Protocol.BOLT9.Types
build-depends:
