def test_chunk_iteration():
chunk_number = COLLATION_SIZE // CHUNK_SIZE
test_chunks = [
zpad_left(int_to_big_endian(i), CHUNK_SIZE)
for i in range(chunk_number)
]
chunks = test_chunks
body = b"".join(chunks)
for recovered, original in zip_longest(iterate_chunks(body),
chunks,
fillvalue=None):
assert recovered is not None and original is not None
assert recovered == original
chunks = test_chunks[:-2]
body = b"".join(chunks)
with pytest.raises(ValidationError):
next(iterate_chunks(body))
chunks = test_chunks
body = b"".join(chunks)[:-2]
with pytest.raises(ValidationError):
next(iterate_chunks(body))
chunks = test_chunks
body = b"".join(chunks) + b"\x00"
with pytest.raises(ValidationError):
next(iterate_chunks(body))
chunks = test_chunks + [b"\x00" * CHUNK_SIZE]
body = b"".join(chunks)
with pytest.raises(ValidationError):
next(iterate_chunks(body))
def modexp(computation):
"""
https://github.com/ethereum/EIPs/pull/198
"""
gas_fee = _compute_modexp_gas_fee(computation.msg.data)
computation.consume_gas(gas_fee, reason='MODEXP Precompile')
result = _modexp(computation.msg.data)
_, _, modulus_length = _extract_lengths(computation.msg.data)
result_bytes = zpad_left(int_to_big_endian(result), to_size=modulus_length)
computation.output = result_bytes
return computation
def modexp(computation: BaseComputation) -> BaseComputation:
"""
https://github.com/ethereum/EIPs/pull/198
"""
gas_fee = _compute_modexp_gas_fee(computation.msg.data)
computation.consume_gas(gas_fee, reason='MODEXP Precompile')
result = _modexp(computation.msg.data)
_, _, modulus_length = _extract_lengths(computation.msg.data)
# Modulo 0 is undefined, return zero
# https://math.stackexchange.com/questions/516251/why-is-n-mod-0-undefined
result_bytes = b'' if modulus_length == 0 else zpad_left(
int_to_big_endian(result), to_size=modulus_length)
computation.output = result_bytes
return computation