def _modexp(data: bytes) -> int:
base_length, exponent_length, modulus_length = extract_lengths(data)
if base_length == 0:
return 0
elif modulus_length == 0:
return 0
# compute start:end indexes
base_end_idx = 96 + base_length
exponent_end_idx = base_end_idx + exponent_length
modulus_end_dx = exponent_end_idx + modulus_length
# extract arguments
modulus_bytes = zpad_right(
data[exponent_end_idx:modulus_end_dx],
to_size=modulus_length,
)
modulus = big_endian_to_int(modulus_bytes)
if modulus == 0:
return 0
base_bytes = zpad_right(data[96:base_end_idx], to_size=base_length)
base = big_endian_to_int(base_bytes)
exponent_bytes = zpad_right(
data[base_end_idx:exponent_end_idx],
to_size=exponent_length,
)
exponent = big_endian_to_int(exponent_bytes)
result = pow(base, exponent, modulus)
return result
def _compute_modexp_gas_fee_eip_198(data: bytes) -> int:
base_length, exponent_length, modulus_length = extract_lengths(data)
first_32_exponent_bytes = zpad_right(
data[96 + base_length:96 + base_length + exponent_length],
to_size=min(exponent_length, 32),
)[:32]
adjusted_exponent_length = _compute_adjusted_exponent_length(
exponent_length,
first_32_exponent_bytes,
)
complexity = _compute_complexity(max(modulus_length, base_length))
gas_fee = (complexity * max(adjusted_exponent_length, 1) //
constants.GAS_MOD_EXP_QUADRATIC_DENOMINATOR)
return gas_fee
def _compute_modexp_gas_fee_eip_2565(data: bytes) -> int:
base_length, exponent_length, modulus_length = extract_lengths(data)
base_end_idx = 96 + base_length
exponent_end_idx = base_end_idx + exponent_length
exponent_bytes = zpad_right(
data[base_end_idx:exponent_end_idx],
to_size=exponent_length,
)
multiplication_complexity = _calculate_multiplication_complexity(base_length, modulus_length)
iteration_count = compute_adjusted_exponent_length(exponent_length, exponent_bytes)
return max(200,
multiplication_complexity * iteration_count
// constants.GAS_MOD_EXP_QUADRATIC_DENOMINATOR_EIP_2565)
def calc_chunk_root(collation_body: bytes) -> Hash32:
check_body_size(collation_body)
chunks = list(iterate_chunks(collation_body))
return get_merkle_root_from_items(chunks)
def check_body_size(body: bytes) -> bytes:
if len(body) != COLLATION_SIZE:
raise ValidationError("{} byte collation body exceeds maximum allowed size".format(
len(body)
))
return body
@apply_to_return_value(check_body_size)
@apply_to_return_value(lambda v: zpad_right(v, COLLATION_SIZE))
@apply_to_return_value(b"".join)
def serialize_blobs(blobs: Iterable[bytes]) -> Iterator[bytes]:
"""Serialize a sequence of blobs and return a collation body."""
for i, blob in enumerate(blobs):
if len(blob) == 0:
raise ValidationError("Cannot serialize blob {} of length 0".format(i))
if len(blob) > MAX_BLOB_SIZE:
raise ValidationError("Cannot serialize blob {} of size {}".format(i, len(blob)))
for blob_index in range(0, len(blob), CHUNK_DATA_SIZE):
remaining_blob_bytes = len(blob) - blob_index
if remaining_blob_bytes <= CHUNK_DATA_SIZE:
length_bits = remaining_blob_bytes
else: