def decode_single(typ, data):
base, sub, _ = typ
if base == 'address':
return encode_hex(data[12:])
elif base == 'hash':
return data[32 - int(sub):]
elif base == 'string' or base == 'bytes':
if len(sub):
return data[:int(sub)]
else:
l = big_endian_to_int(data[0:32])
return data[32:][:l]
elif base == 'uint':
return big_endian_to_int(data)
elif base == 'int':
o = big_endian_to_int(data)
return (o - 2 ** int(sub)) if o >= 2 ** (int(sub) - 1) else o
elif base == 'ufixed':
high, low = [int(x) for x in sub.split('x')]
return big_endian_to_int(data) * 1.0 // 2 ** low
elif base == 'fixed':
high, low = [int(x) for x in sub.split('x')]
o = big_endian_to_int(data)
i = (o - 2 ** (high + low)) if o >= 2 ** (high + low - 1) else o
return (i * 1.0 // 2 ** low)
elif base == 'bool':
return bool(int(encode_hex(data), 16))
def _encode_function(self, signature, param_values):
prefix = utils.big_endian_to_int(utils.sha3(signature)[:4])
if signature.find('(') == -1:
raise RuntimeError('Invalid function signature. Missing "(" and/or ")"...')
if signature.find(')') - signature.find('(') == 1:
return utils.encode_int(prefix)
types = signature[signature.find('(') + 1: signature.find(')')].split(',')
encoded_params = encode_abi(types, param_values)
return utils.zpad(utils.encode_int(prefix), 4) + encoded_params
def dec(typ, arg):
base, sub, arrlist = typ
sz = get_size(typ)
# Dynamic-sized strings are encoded as <len(str)> + <str>
if base in ('string', 'bytes') and not sub:
L = big_endian_to_int(arg[:32])
assert len(arg[32:]) == ceil32(L), "Wrong data size for string/bytes object"
return arg[32:][:L]
# Dynamic-sized arrays
elif sz is None:
L = big_endian_to_int(arg[:32])
subtyp = base, sub, arrlist[:-1]
subsize = get_size(subtyp)
# If children are dynamic, use the head/tail mechanism. Fortunately,
# here the code is simpler since we do not have to worry about
# mixed dynamic and static children, as we do in the top-level multi-arg
# case
if subsize is None:
assert len(arg) >= 32 + 32 * L, "Not enough data for head"
start_positions = [big_endian_to_int(arg[32 + 32 * i: 64 + 32 * i])
for i in range(L)] + [len(arg)]
outs = [arg[start_positions[i]: start_positions[i + 1]]
for i in range(L)]
return [dec(subtyp, out) for out in outs]
# If children are static, then grab the data slice for each one and
# sequentially decode them manually
else:
return [dec(subtyp, arg[32 + subsize * i: 32 + subsize * (i + 1)])
for i in range(L)]
# Static-sized arrays: decode piece-by-piece
elif len(arrlist):
L = arrlist[-1][0]
subtyp = base, sub, arrlist[:-1]
subsize = get_size(subtyp)
return [dec(subtyp, arg[subsize * i:subsize * (i + 1)])
for i in range(L)]
else:
return decode_single(typ, arg)
def _encode_function(self, signature, param_values):
prefix = utils.big_endian_to_int(utils.sha3(signature)[:4])
if signature.find('(') == -1:
raise RuntimeError(
'Invalid function signature. Missing "(" and/or ")"...')
if signature.find(')') - signature.find('(') == 1:
return utils.encode_int(prefix)
types = signature[signature.find('(') +
1:signature.find(')')].split(',')
encoded_params = encode_abi(types, param_values)
return utils.zpad(utils.encode_int(prefix), 4) + encoded_params
def decint(n, signed=False): # pylint: disable=invalid-name,too-many-branches
''' Decode an unsigned/signed integer. '''
if isinstance(n, str):
n = utils.to_string(n)
if n is True:
return 1
if n is False:
return 0
if n is None:
return 0
if is_numeric(n):
if signed:
if not -TT255 <= n <= TT255 - 1:
raise EncodingError('Number out of range: %r' % n)
else:
if not 0 <= n <= TT256 - 1:
raise EncodingError('Number out of range: %r' % n)
return n
if is_string(n):
if len(n) > 32:
raise EncodingError('String too long: %r' % n)
if len(n) == 40:
int_bigendian = decode_hex(n)
else:
int_bigendian = n # pylint: disable=redefined-variable-type
result = big_endian_to_int(int_bigendian)
if signed:
if result >= TT255:
result -= TT256
if not -TT255 <= result <= TT255 - 1:
raise EncodingError('Number out of range: %r' % n)
else:
if not 0 <= result <= TT256 - 1:
raise EncodingError('Number out of range: %r' % n)
return result
raise EncodingError('Cannot decode integer: %r' % n)
def decode_abi(types, data):
# Process types
proctypes = [process_type(typ) for typ in types]
# Get sizes of everything
sizes = [get_size(typ) for typ in proctypes]
# Initialize array of outputs
outs = [None] * len(types)
# Initialize array of start positions
start_positions = [None] * len(types) + [len(data)]
# If a type is static, grab the data directly, otherwise record
# its start position
pos = 0
for i, typ in enumerate(types):
if sizes[i] is None:
start_positions[i] = big_endian_to_int(data[pos:pos + 32])
j = i - 1
while j >= 0 and start_positions[j] is None:
start_positions[j] = start_positions[i]
j -= 1
pos += 32
else:
outs[i] = data[pos:pos + sizes[i]]
pos += sizes[i]
# We add a start position equal to the length of the entire data
# for convenience.
j = len(types) - 1
while j >= 0 and start_positions[j] is None:
start_positions[j] = start_positions[len(types)]
j -= 1
assert pos <= len(data), "Not enough data for head"
# Grab the data for tail arguments using the start positions
# calculated above
for i, typ in enumerate(types):
if sizes[i] is None:
offset = start_positions[i]
next_offset = start_positions[i + 1]
outs[i] = data[offset:next_offset]
# Recursively decode them all
return [dec(proctypes[i], outs[i]) for i in range(len(outs))]
def event_id(name, encode_types):
""" Return the event id.
Defined as:
`keccak(EVENT_NAME+"("+EVENT_ARGS.map(canonical_type_of).join(",")+")")`
Where `canonical_type_of` is a function that simply returns the canonical
type of a given argument, e.g. for uint indexed foo, it would return
uint256). Note the lack of spaces.
"""
event_types = [
_canonical_type(type_)
for type_ in encode_types
]
event_signature = '{event_name}({canonical_types})'.format(
event_name=name,
canonical_types=','.join(event_types),
)
return big_endian_to_int(utils.sha3(event_signature))
def method_id(name, encode_types):
""" Return the unique method id.
The signature is defined as the canonical expression of the basic
prototype, i.e. the function name with the parenthesised list of parameter
types. Parameter types are split by a single comma - no spaces are used.
The method id is defined as the first four bytes (left, high-order in
big-endian) of the Keccak (SHA-3) hash of the signature of the function.
"""
function_types = [
_canonical_type(type_)
for type_ in encode_types
]
function_signature = '{function_name}({canonical_types})'.format(
function_name=name,
canonical_types=','.join(function_types),
)
function_keccak = utils.sha3(function_signature)
first_bytes = function_keccak[:4]
return big_endian_to_int(first_bytes)