Constants.hs

-- | Module      : MultiFormats.CID.Constants
--   Description : Defines constants used in CIDs
--   Copyright   : Zoey McBride (c) 2026
--   License     : AGPL-3.0-or-later
--   Maintainer  : zoeymcbride@mailbox.org
--   Stability   : experimental
module MultiFormats.CID.Constants
  ( -- * Versioning magic numbers
    v0EncodingPrefix,
    v0FirstByte,
    v0SecondByte,
    v1FirstVarInt,

    -- * Versioning metadata
    v0EncodingLength,
    v0TotalBytes,
    v0HashBytes,

    -- * CBOR tag number for IPLD's DAG-CBOR specification.
    ipldTagCBOR,
  )
where

import Data.Word (Word8)
import MultiFormats.VarInt (VarInt)

-- | This prefixes a CIDv0 instead of a multibase prefix.
v0EncodingPrefix :: String
v0EncodingPrefix = "Qm"

-- | The length of a CIDv0 string, base58 encoded.
v0EncodingLength :: Int
v0EncodingLength = 46

-- | Required length in bytes of all CIDv0 encodings.
v0TotalBytes :: Int
v0TotalBytes = 34

-- | Length of hash digest in CIDv0, ie the length without its versioning
-- information, since those are the only items in CIDv0.
v0HashBytes :: Int
v0HashBytes = v0TotalBytes - 2

-- | Required first byte of all CIDv0 encodings.
v0FirstByte :: Word8
v0FirstByte = 0x12

-- | Required second byte of all CIDv0 encodings.
v0SecondByte :: Word8
v0SecondByte = 0x20

-- | Required first VarInt of all CIDv1 encodings.
v1FirstVarInt :: VarInt
v1FirstVarInt = 1

-- | Used for CBOR tagged major-types to identify CID encoded bytestrings.
ipldTagCBOR :: Word8
ipldTagCBOR = 42