nimbus-eth2/beacon_chain/merkle_minimal.nim

43 lines
1.6 KiB
Nim

# beacon_chain
# Copyright (c) 2018-2020 Status Research & Development GmbH
# Licensed and distributed under either of
# * MIT license (license terms in the root directory or at https://opensource.org/licenses/MIT).
# * Apache v2 license (license terms in the root directory or at https://www.apache.org/licenses/LICENSE-2.0).
# at your option. This file may not be copied, modified, or distributed except according to those terms.
# https://github.com/ethereum/eth2.0-specs/blob/v1.0.0/tests/core/pyspec/eth2spec/utils/merkle_minimal.py
# Merkle tree helpers
# ---------------------------------------------------------------
{.push raises: [Defect].}
import
sequtils,
stew/endians2,
# Specs
../../beacon_chain/spec/[datatypes, digest],
../../beacon_chain/ssz/merkleization
const depositContractLimit* = Limit(1'u64 shl DEPOSIT_CONTRACT_TREE_DEPTH)
func attachMerkleProofs*(deposits: var openArray[Deposit]) =
let depositsRoots = mapIt(deposits, hash_tree_root(it.data))
var incrementalMerkleProofs = createMerkleizer(depositContractLimit)
for i in 0 ..< depositsRoots.len:
incrementalMerkleProofs.addChunkAndGenMerkleProof(depositsRoots[i], deposits[i].proof)
deposits[i].proof[32] = default(Eth2Digest)
deposits[i].proof[32].data[0..7] = toBytesLE uint64(i + 1)
template getProof*(proofs: seq[Eth2Digest], idxParam: int): openArray[Eth2Digest] =
let
idx = idxParam
## TODO: It's surprising that we have to do +1 here.
## It seems that `depositContractLimit` is set too high.
startIdx = idx * (DEPOSIT_CONTRACT_TREE_DEPTH + 1)
endIdx = startIdx + DEPOSIT_CONTRACT_TREE_DEPTH - 1
proofs.toOpenArray(startIdx, endIdx)