bech32

commit 52a11137e17d1ca94239d815abc5eac36b3aef00
parent 085944fd037672e264a186cd54d83ac9ca21c308
Author: Jared Tobin <jared@jtobin.io>
Date:   Sat, 14 Dec 2024 04:08:45 -0330

lib: s/verify_checksum/verify

Strikes me as having better UX.

Diffstat:
M
lib/Data/ByteString/Base32.hs
 | 
17
++++++++++-------
M
lib/Data/ByteString/Bech32.hs
 | 
16
+++++++---------
M
lib/Data/ByteString/Bech32m.hs
 | 
16
+++++++---------

3 files changed, 24 insertions(+), 25 deletions(-)
diff --git a/lib/Data/ByteString/Base32.hs b/lib/Data/ByteString/Base32.hs
@@ -11,7 +11,7 @@ module Data.ByteString.Base32 (
   -- not actually base32-related, but convenient to put here
   , Encoding(..)
   , create_checksum
-  , verify_checksum
+  , verify
   , valid_hrp
   ) where
 
@@ -204,10 +204,13 @@ create_checksum enc hrp dat =
 
   in  BS.map code "\EM\DC4\SI\n\ENQ\NUL" -- BS.pack [25, 20, 15, 10, 5, 0]
 
-verify_checksum :: Encoding -> BS.ByteString -> BS.ByteString -> Bool
-verify_checksum enc hrp dat =
-  let bs = hrp_expand hrp <> as_word5 dat
-  in  polymod bs == case enc of
-        Bech32 -> 1
-        Bech32m -> _BECH32M_CONST
+verify :: Encoding -> BS.ByteString -> Bool
+verify enc b32 = case BS.elemIndexEnd 0x31 b32 of
+  Nothing  -> False
+  Just idx ->
+    let (hrp, BS.drop 1 -> dat) = BS.splitAt idx b32
+        bs = hrp_expand hrp <> as_word5 dat
+    in  polymod bs == case enc of
+          Bech32 -> 1
+          Bech32m -> _BECH32M_CONST
 
diff --git a/lib/Data/ByteString/Bech32.hs b/lib/Data/ByteString/Bech32.hs
@@ -2,7 +2,7 @@
 
 module Data.ByteString.Bech32 (
     encode
-  , verify_checksum
+  , verify
   ) where
 
 import Control.Monad (guard)
@@ -20,18 +20,16 @@ toStrict = BS.toStrict
 create_checksum :: BS.ByteString -> BS.ByteString -> BS.ByteString
 create_checksum = B32.create_checksum Bech32
 
--- | Verify a Bech32 checksum, given human-readable and data parts.
+-- | Verify that a bech32 string has a valid checksum.
 --
---   >>> let Just bech32 = encode "bc" "my string"
---   >>> verify_checksum "bc" "d4ujqum5wf5kuecmu02w2"
+--   >>> verify "bc1d4ujqum5wf5kuecmu02w2"
 --   True
---   >>> verify_checksum "bc" "d4ujquw5wf5kuecmu02w2" -- s/m/w
+--   >>> verify "bc1d4ujquw5wf5kuecmu02w2" -- s/m/w
 --   False
-verify_checksum
-  :: BS.ByteString -- ^ base255-encoded human-readable part
-  -> BS.ByteString -- ^ bech32-encoded data part
+verify
+  :: BS.ByteString -- ^ bech32-encoded bytestring
   -> Bool
-verify_checksum = B32.verify_checksum Bech32
+verify = B32.verify Bech32
 
 -- | Encode a base255 human-readable part and input as Bech32.
 --
diff --git a/lib/Data/ByteString/Bech32m.hs b/lib/Data/ByteString/Bech32m.hs
@@ -2,7 +2,7 @@
 
 module Data.ByteString.Bech32m (
     encode
-  , verify_checksum
+  , verify
   ) where
 
 import Control.Monad (guard)
@@ -20,18 +20,16 @@ toStrict = BS.toStrict
 create_checksum :: BS.ByteString -> BS.ByteString -> BS.ByteString
 create_checksum = B32.create_checksum Bech32m
 
--- | Verify a Bech32m checksum, given human-readable and data parts.
+-- | Verify that a bech32m string has a valid checksum.
 --
---   >>> let Just bech32m = encode "bc" "my string"
---   >>> verify_checksum "bc" "d4ujqum5wf5kuecwqlxtg"
+--   >>> verify "bc1d4ujqum5wf5kuecwqlxtg"
 --   True
---   >>> verify_checksum "bc" "d4ujquw5wf5kuecwqlxtg" -- s/m/w
+--   >>> verify "bc1d4ujquw5wf5kuecwqlxtg" -- s/m/w
 --   False
-verify_checksum
-  :: BS.ByteString -- ^ base255-encoded human-readable part
-  -> BS.ByteString -- ^ bech32-encoded data part
+verify
+  :: BS.ByteString -- ^ bech32m-encoded bytestring
   -> Bool
-verify_checksum = B32.verify_checksum Bech32m
+verify = B32.verify Bech32m
 
 -- | Encode a base255 human-readable part and input as Bech32m.
 --