def replace_shortcut_ops(instructions):
"""Replace opcodes with a corresponding shortcut form."""
optimizations = []
# Replace division by 2.
# OP_2 OP_DIV -> OP_2DIV
optimizations.append(([types.Two(), types.Div()], lambda values: [types.Div2()]))
# Replace subtraction by 1.
# OP_1 OP_SUB -> OP_1SUB
optimizations.append(([types.One(), types.Sub()], lambda values: [types.Sub1()]))
# Replace 1 * -1 with -1.
# OP_1 OP_NEGATE -> OP_1NEGATE
optimizations.append(([types.One(), types.Negate()], lambda values: [types.NegativeOne()]))
# Replace addition by 1.
# OP_1 OP_ADD -> OP_1ADD
for permutation in permutations([types.Push(), types.One()]) + permutations([types.SmallIntOpCode(), types.One()]):
idx = 0 if not isinstance(permutation[0], types.One) else 1
optimizations.append((permutation + [types.Add()], lambda values, idx=idx: [values[idx], types.Add1()]))
optimizations.append(([types.Assumption(), types.One(), types.Add()], lambda values: [values[0], types.Add1()]))
# Replace multiplication by 2.
# OP_2 OP_MUL -> OP_2MUL
for permutation in permutations([types.Push(), types.Two()]) + permutations([types.SmallIntOpCode(), types.Two()]):
idx = 0 if not isinstance(permutation[0], types.Two) else 1
optimizations.append((permutation + [types.Mul()], lambda values, idx=idx: [values[idx], types.Mul2()]))
optimizations.append(([types.Assumption(), types.Two(), types.Mul()], lambda values: [values[0], types.Mul2()]))
for template, callback in optimizations:
instructions.replace_template(template, callback, strict=False)
def test_shortcut_ops(self):
for script in [
[types.Five(), types.One(), types.Add()],
[types.One(), types.Five(), types.Add()],
]:
self._do_test('OP_5 OP_1ADD', script)
self._do_test('OP_1ADD', [types.Assumption('testItem'), types.One(), types.Add()])
script = [types.Five(), types.One(), types.Sub()]
self._do_test('OP_5 OP_1SUB', script)
for script in [
[types.Five(), types.Two(), types.Mul()],
[types.Two(), types.Five(), types.Mul()],
]:
self._do_test('OP_5 OP_2MUL', script)
self._do_test('OP_2MUL', [types.Assumption('testItem'), types.Two(), types.Mul()])
script = [types.Five(), types.Two(), types.Div()]
self._do_test('OP_5 OP_2DIV', script)
script = [types.Five(), types.One(), types.Negate()]
self._do_test('OP_5 OP_1NEGATE', script)
def test_small_int(self):
items = [
(LInstructions([types.One(), types.Two(), types.IfDup()]), 1),
(LInstructions([types.One(), types.Zero(), types.IfDup()]), 0),
]
for script, expected_delta in items:
self._do_context(script)
ifdup = script[2]
self.assertIsInstance(ifdup, types.IfDup)
self.assertEqual(expected_delta, ifdup.delta)
def test_optimize_stack_ops(self):
script = [types.Five(), types.One(), types.Pick()]
self._do_test('OP_5 OP_OVER', script)
script = [types.Five(), types.One(), types.Roll(), types.Drop()]
self._do_test('OP_5 OP_NIP', script)
script = [types.Zero(), types.Pick()]
self._do_test('OP_DUP', script)
script = [types.Five(), types.Zero(), types.Roll()]
self._do_test('OP_5', script)
script = [types.Five(), types.Six(), types.One(), types.Roll(), types.One(), types.Roll()]
self._do_test('OP_5 OP_6', script)
def optimize_stack_ops(instructions):
"""Optimize stack operations."""
for template, replacement in [
# OP_1 OP_PICK -> OP_OVER
([types.One(), types.Pick()], [types.Over()]),
# OP_1 OP_ROLL OP_DROP -> OP_NIP
([types.One(), types.Roll(), types.Drop()], [types.Nip()]),
# OP_0 OP_PICK -> OP_DUP
([types.Zero(), types.Pick()], [types.Dup()]),
# OP_0 OP_ROLL -> _
([types.Zero(), types.Roll()], []),
# OP_1 OP_ROLL OP_1 OP_ROLL -> _
([types.One(), types.Roll(), types.One(), types.Roll()], []),
# OP_1 OP_ROLL -> OP_SWAP
([types.One(), types.Roll()], [types.Swap()]),
# OP_NIP OP_DROP -> OP_2DROP
([types.Nip(), types.Drop()], [types.TwoDrop()]),
# OP_OVER OP_OVER -> OP_2DUP
([types.Over(), types.Over()], [types.TwoDup()]),
]:
callback = lambda values, replacement=replacement: replacement
instructions.replace_template(template, callback)
def test_multisig(self):
sigs = [types.Push(formats.int_to_bytearray(i)) for i in [100]]
pubs = [types.Push(formats.int_to_bytearray(i)) for i in [300, 400]]
script = [types.Zero()] # Dummy value.
script.extend(sigs + [types.One()]) # 1 signature.
script.extend(pubs + [types.Two()]) # 2 public keys.
script.append(types.CheckMultiSig())
script = LInstructions(script)
self._do_context(script)
checkmultisig = script[6]
self.assertIsInstance(checkmultisig, types.CheckMultiSig)
self.assertEqual(2, checkmultisig.num_pubkeys)
self.assertEqual(1, checkmultisig.num_sigs)
def test_push(self):
script = LInstructions([types.One(), types.Push(formats.int_to_bytearray(20)), types.IfDup()])
self._do_context(script)
ifdup = script[2]
self.assertIsInstance(ifdup, types.IfDup)
self.assertEqual(1, ifdup.delta)