75 lines
1.9 KiB
Python
75 lines
1.9 KiB
Python
from .hash_function import hash
|
|
|
|
|
|
ZERO_BYTES32 = b'\x00' * 32
|
|
|
|
zerohashes = [ZERO_BYTES32]
|
|
for layer in range(1, 32):
|
|
zerohashes.append(hash(zerohashes[layer - 1] + zerohashes[layer - 1]))
|
|
|
|
|
|
# Compute a Merkle root of a right-zerobyte-padded 2**32 sized tree
|
|
def calc_merkle_tree_from_leaves(values):
|
|
values = list(values)
|
|
tree = [values[::]]
|
|
for h in range(32):
|
|
if len(values) % 2 == 1:
|
|
values.append(zerohashes[h])
|
|
values = [hash(values[i] + values[i + 1]) for i in range(0, len(values), 2)]
|
|
tree.append(values[::])
|
|
return tree
|
|
|
|
|
|
def get_merkle_root(values):
|
|
return calc_merkle_tree_from_leaves(values)[-1][0]
|
|
|
|
|
|
def get_merkle_proof(tree, item_index):
|
|
proof = []
|
|
for i in range(32):
|
|
subindex = (item_index // 2**i) ^ 1
|
|
proof.append(tree[i][subindex] if subindex < len(tree[i]) else zerohashes[i])
|
|
return proof
|
|
|
|
|
|
def next_power_of_two(v: int) -> int:
|
|
"""
|
|
Get the next power of 2. (for 64 bit range ints).
|
|
0 is a special case, to have non-empty defaults.
|
|
Examples:
|
|
0 -> 1, 1 -> 1, 2 -> 2, 3 -> 4, 32 -> 32, 33 -> 64
|
|
"""
|
|
if v == 0:
|
|
return 1
|
|
return 1 << (v - 1).bit_length()
|
|
|
|
|
|
def merkleize_chunks(chunks, pad_to: int = None):
|
|
count = len(chunks)
|
|
depth = max(count - 1, 0).bit_length()
|
|
max_depth = max(depth, (pad_to - 1).bit_length())
|
|
tmp = [None for _ in range(max_depth + 1)]
|
|
|
|
def merge(h, i):
|
|
j = 0
|
|
while True:
|
|
if i & (1 << j) == 0:
|
|
if i == count and j < depth:
|
|
h = hash(h + zerohashes[j])
|
|
else:
|
|
break
|
|
else:
|
|
h = hash(tmp[j] + h)
|
|
j += 1
|
|
tmp[j] = h
|
|
|
|
for i in range(count):
|
|
merge(chunks[i], i)
|
|
|
|
merge(zerohashes[0], count)
|
|
|
|
for j in range(depth, max_depth):
|
|
tmp[j + 1] = hash(tmp[j] + zerohashes[j])
|
|
|
|
return tmp[max_depth]
|