import array import unittest import struct import sys from test.support import run_unittest ISBIGENDIAN = sys.byteorder == "big" IS32BIT = sys.maxsize == 0x7fffffff def string_reverse(s): return s[::-1] def bigendian_to_native(value): if ISBIGENDIAN: return value else: return string_reverse(value) class StructTest(unittest.TestCase): def test_isbigendian(self): self.assertEqual((struct.pack('=i', 1)[0] == 0), ISBIGENDIAN) def test_consistence(self): self.assertRaises(struct.error, struct.calcsize, 'Z') sz = struct.calcsize('i') self.assertEqual(sz * 3, struct.calcsize('iii')) fmt = 'cbxxxxxxhhhhiillffd?' fmt3 = '3c3b18x12h6i6l6f3d3?' sz = struct.calcsize(fmt) sz3 = struct.calcsize(fmt3) self.assertEqual(sz * 3, sz3) self.assertRaises(struct.error, struct.pack, 'iii', 3) self.assertRaises(struct.error, struct.pack, 'i', 3, 3, 3) self.assertRaises(struct.error, struct.pack, 'i', 'foo') self.assertRaises(struct.error, struct.pack, 'P', 'foo') self.assertRaises(struct.error, struct.unpack, 'd', b'flap') s = struct.pack('ii', 1, 2) self.assertRaises(struct.error, struct.unpack, 'iii', s) self.assertRaises(struct.error, struct.unpack, 'i', s) def test_transitiveness(self): c = b'a' b = 1 h = 255 i = 65535 l = 65536 f = 3.1415 d = 3.1415 t = True for prefix in ('', '@', '<', '>', '=', '!'): for format in ('xcbhilfd?', 'xcBHILfd?'): format = prefix + format s = struct.pack(format, c, b, h, i, l, f, d, t) cp, bp, hp, ip, lp, fp, dp, tp = struct.unpack(format, s) self.assertEqual(cp, c) self.assertEqual(bp, b) self.assertEqual(hp, h) self.assertEqual(ip, i) self.assertEqual(lp, l) self.assertEqual(int(100 * fp), int(100 * f)) self.assertEqual(int(100 * dp), int(100 * d)) self.assertEqual(tp, t) def test_new_features(self): # Test some of the new features in detail # (format, argument, big-endian result, little-endian result, asymmetric) tests = [ ('c', 'a', 'a', 'a', 0), ('xc', 'a', '\0a', '\0a', 0), ('cx', 'a', 'a\0', 'a\0', 0), ('s', 'a', 'a', 'a', 0), ('0s', 'helloworld', '', '', 1), ('1s', 'helloworld', 'h', 'h', 1), ('9s', 'helloworld', 'helloworl', 'helloworl', 1), ('10s', 'helloworld', 'helloworld', 'helloworld', 0), ('11s', 'helloworld', 'helloworld\0', 'helloworld\0', 1), ('20s', 'helloworld', 'helloworld'+10*'\0', 'helloworld'+10*'\0', 1), ('b', 7, '\7', '\7', 0), ('b', -7, '\371', '\371', 0), ('B', 7, '\7', '\7', 0), ('B', 249, '\371', '\371', 0), ('h', 700, '\002\274', '\274\002', 0), ('h', -700, '\375D', 'D\375', 0), ('H', 700, '\002\274', '\274\002', 0), ('H', 0x10000-700, '\375D', 'D\375', 0), ('i', 70000000, '\004,\035\200', '\200\035,\004', 0), ('i', -70000000, '\373\323\342\200', '\200\342\323\373', 0), ('I', 70000000, '\004,\035\200', '\200\035,\004', 0), ('I', 0x100000000-70000000, '\373\323\342\200', '\200\342\323\373', 0), ('l', 70000000, '\004,\035\200', '\200\035,\004', 0), ('l', -70000000, '\373\323\342\200', '\200\342\323\373', 0), ('L', 70000000, '\004,\035\200', '\200\035,\004', 0), ('L', 0x100000000-70000000, '\373\323\342\200', '\200\342\323\373', 0), ('f', 2.0, '@\000\000\000', '\000\000\000@', 0), ('d', 2.0, '@\000\000\000\000\000\000\000', '\000\000\000\000\000\000\000@', 0), ('f', -2.0, '\300\000\000\000', '\000\000\000\300', 0), ('d', -2.0, '\300\000\000\000\000\000\000\000', '\000\000\000\000\000\000\000\300', 0), ('?', 0, '\0', '\0', 0), ('?', 3, '\1', '\1', 1), ('?', True, '\1', '\1', 0), ('?', [], '\0', '\0', 1), ('?', (1,), '\1', '\1', 1), ] for fmt, arg, big, lil, asy in tests: big = bytes(big, "latin-1") lil = bytes(lil, "latin-1") for (xfmt, exp) in [('>'+fmt, big), ('!'+fmt, big), ('<'+fmt, lil), ('='+fmt, ISBIGENDIAN and big or lil)]: res = struct.pack(xfmt, arg) self.assertEqual(res, exp) self.assertEqual(struct.calcsize(xfmt), len(res)) rev = struct.unpack(xfmt, res)[0] if isinstance(arg, str): # Strings are returned as bytes since you can't know the # encoding of the string when packed. arg = bytes(arg, 'latin1') if rev != arg: self.assertTrue(asy) def test_native_qQ(self): # can't pack -1 as unsigned regardless self.assertRaises((struct.error, OverflowError), struct.pack, "Q", -1) # can't pack string as 'q' regardless self.assertRaises(struct.error, struct.pack, "q", "a") # ditto, but 'Q' self.assertRaises(struct.error, struct.pack, "Q", "a") try: struct.pack("q", 5) except struct.error: # does not have native q/Q pass else: nbytes = struct.calcsize('q') # The expected values here are in big-endian format, primarily # because I'm on a little-endian machine and so this is the # clearest way (for me) to force the code to get exercised. for format, input, expected in ( ('q', -1, '\xff' * nbytes), ('q', 0, '\x00' * nbytes), ('Q', 0, '\x00' * nbytes), ('q', 1, '\x00' * (nbytes-1) + '\x01'), ('Q', (1 << (8*nbytes))-1, '\xff' * nbytes), ('q', (1 << (8*nbytes-1))-1, '\x7f' + '\xff' * (nbytes - 1))): expected = bytes(expected, "latin-1") got = struct.pack(format, input) native_expected = bigendian_to_native(expected) self.assertEqual(got, native_expected) retrieved = struct.unpack(format, got)[0] self.assertEqual(retrieved, input) def test_standard_integers(self): # Standard integer tests (bBhHiIlLqQ). import binascii class IntTester(unittest.TestCase): def __init__(self, formatpair, bytesize): super(IntTester, self).__init__(methodName='test_one') self.assertEqual(len(formatpair), 2) self.formatpair = formatpair for direction in "<>!=": for code in formatpair: format = direction + code self.assertEqual(struct.calcsize(format), bytesize) self.bytesize = bytesize self.bitsize = bytesize * 8 self.signed_code, self.unsigned_code = formatpair self.unsigned_min = 0 self.unsigned_max = 2**self.bitsize - 1 self.signed_min = -(2**(self.bitsize-1)) self.signed_max = 2**(self.bitsize-1) - 1 def test_one(self, x, pack=struct.pack, unpack=struct.unpack, unhexlify=binascii.unhexlify): # Try signed. code = self.signed_code if self.signed_min <= x <= self.signed_max: # Try big-endian. expected = x if x < 0: expected += 1 << self.bitsize self.assertTrue(expected > 0) expected = hex(expected)[2:] # chop "0x" if len(expected) & 1: expected = "0" + expected expected = unhexlify(expected) expected = b"\x00" * (self.bytesize - len(expected)) + expected # Pack work? format = ">" + code got = pack(format, x) self.assertEqual(got, expected) # Unpack work? retrieved = unpack(format, got)[0] self.assertEqual(x, retrieved) # Adding any byte should cause a "too big" error. self.assertRaises((struct.error, TypeError), unpack, format, b'\x01' + got) # Try little-endian. format = "<" + code expected = string_reverse(expected) # Pack work? got = pack(format, x) self.assertEqual(got, expected) # Unpack work? retrieved = unpack(format, got)[0] self.assertEqual(x, retrieved) # Adding any byte should cause a "too big" error. self.assertRaises((struct.error, TypeError), unpack, format, b'\x01' + got) else: # x is out of range -- verify pack realizes that. self.assertRaises(struct.error, pack, ">" + code, x) self.assertRaises(struct.error, pack, "<" + code, x) # Much the same for unsigned. code = self.unsigned_code if self.unsigned_min <= x <= self.unsigned_max: # Try big-endian. format = ">" + code expected = x expected = hex(expected)[2:] # chop "0x" if len(expected) & 1: expected = "0" + expected expected = unhexlify(expected) expected = b"\x00" * (self.bytesize - len(expected)) + expected # Pack work? got = pack(format, x) self.assertEqual(got, expected) # Unpack work? retrieved = unpack(format, got)[0] self.assertEqual(x, retrieved) # Adding any byte should cause a "too big" error. self.assertRaises((struct.error, TypeError), unpack, format, b'\x01' + got) # Try little-endian. format = "<" + code expected = string_reverse(expected) # Pack work? got = pack(format, x) self.assertEqual(got, expected) # Unpack work? retrieved = unpack(format, got)[0] self.assertEqual(x, retrieved) # Adding any byte should cause a "too big" error. self.assertRaises((struct.error, TypeError), unpack, format, b'\x01' + got) else: # x is out of range -- verify pack realizes that. self.assertRaises(struct.error, pack, ">" + code, x) self.assertRaises(struct.error, pack, "<" + code, x) def run(self): from random import randrange # Create all interesting powers of 2. values = [] for exp in range(self.bitsize + 3): values.append(1 << exp) # Add some random values. for i in range(self.bitsize): val = 0 for j in range(self.bytesize): val = (val << 8) | randrange(256) values.append(val) # Try all those, and their negations, and +-1 from them. Note # that this tests all power-of-2 boundaries in range, and a few out # of range, plus +-(2**n +- 1). for base in values: for val in -base, base: for incr in -1, 0, 1: x = val + incr try: x = int(x) except OverflowError: pass self.test_one(x) # Some error cases. for direction in "<>": for code in self.formatpair: for badobject in "a string", 3+42j, randrange, -1729.0: self.assertRaises(struct.error, struct.pack, direction + code, badobject) for args in [("bB", 1), ("hH", 2), ("iI", 4), ("lL", 4), ("qQ", 8)]: t = IntTester(*args) t.run() def test_p_code(self): # Test p ("Pascal string") code. for code, input, expected, expectedback in [ ('p','abc', '\x00', b''), ('1p', 'abc', '\x00', b''), ('2p', 'abc', '\x01a', b'a'), ('3p', 'abc', '\x02ab', b'ab'), ('4p', 'abc', '\x03abc', b'abc'), ('5p', 'abc', '\x03abc\x00', b'abc'), ('6p', 'abc', '\x03abc\x00\x00', b'abc'), ('1000p', 'x'*1000, '\xff' + 'x'*999, b'x'*255)]: expected = bytes(expected, "latin-1") got = struct.pack(code, input) self.assertEqual(got, expected) (got,) = struct.unpack(code, got) self.assertEqual(got, expectedback) def test_705836(self): # SF bug 705836. "f" had a severe rounding bug, where a carry # from the low-order discarded bits could propagate into the exponent # field, causing the result to be wrong by a factor of 2. import math for base in range(1, 33): # smaller <- largest representable float less than base. delta = 0.5 while base - delta / 2.0 != base: delta /= 2.0 smaller = base - delta # Packing this rounds away a solid string of trailing 1 bits. packed = struct.pack("f", smaller) self.assertEqual(bigpacked, string_reverse(packed)) unpacked = struct.unpack(">f", bigpacked)[0] self.assertEqual(base, unpacked) # Largest finite IEEE single. big = (1 << 24) - 1 big = math.ldexp(big, 127 - 23) packed = struct.pack(">f", big) unpacked = struct.unpack(">f", packed)[0] self.assertEqual(big, unpacked) # The same, but tack on a 1 bit so it rounds up to infinity. big = (1 << 25) - 1 big = math.ldexp(big, 127 - 24) self.assertRaises(OverflowError, struct.pack, ">f", big) def test_1229380(self): # SF bug 1229380. No struct.pack exception for some out of # range integers for endian in ('', '>', '<'): for fmt in ('B', 'H', 'I', 'L'): self.assertRaises((struct.error, OverflowError), struct.pack, endian + fmt, -1) self.assertRaises((struct.error, OverflowError), struct.pack, endian + 'B', 300) self.assertRaises((struct.error, OverflowError), struct.pack, endian + 'H', 70000) self.assertRaises((struct.error, OverflowError), struct.pack, endian + 'I', sys.maxsize * 4) self.assertRaises((struct.error, OverflowError), struct.pack, endian + 'L', sys.maxsize * 4) def test_1530559(self): for endian in ('', '>', '<'): for fmt in ('B', 'H', 'I', 'L', 'Q', 'b', 'h', 'i', 'l', 'q'): self.assertRaises(struct.error, struct.pack, endian + fmt, 1.0) self.assertRaises(struct.error, struct.pack, endian + fmt, 1.5) self.assertRaises(struct.error, struct.pack, 'P', 1.0) self.assertRaises(struct.error, struct.pack, 'P', 1.5) def test_unpack_from(self): test_string = b'abcd01234' fmt = '4s' s = struct.Struct(fmt) for cls in (bytes, bytearray): data = cls(test_string) if not isinstance(data, (bytes, bytearray)): bytes_data = bytes(data, 'latin1') else: bytes_data = data self.assertEqual(s.unpack_from(data), (b'abcd',)) self.assertEqual(s.unpack_from(data, 2), (b'cd01',)) self.assertEqual(s.unpack_from(data, 4), (b'0123',)) for i in range(6): self.assertEqual(s.unpack_from(data, i), (bytes_data[i:i+4],)) for i in range(6, len(test_string) + 1): self.assertRaises(struct.error, s.unpack_from, data, i) for cls in (bytes, bytearray): data = cls(test_string) self.assertEqual(struct.unpack_from(fmt, data), (b'abcd',)) self.assertEqual(struct.unpack_from(fmt, data, 2), (b'cd01',)) self.assertEqual(struct.unpack_from(fmt, data, 4), (b'0123',)) for i in range(6): self.assertEqual(struct.unpack_from(fmt, data, i), (data[i:i+4],)) for i in range(6, len(test_string) + 1): self.assertRaises(struct.error, struct.unpack_from, fmt, data, i) def test_pack_into(self): test_string = b'Reykjavik rocks, eow!' writable_buf = array.array('b', b' '*100) fmt = '21s' s = struct.Struct(fmt) # Test without offset s.pack_into(writable_buf, 0, test_string) from_buf = writable_buf.tostring()[:len(test_string)] self.assertEqual(from_buf, test_string) # Test with offset. s.pack_into(writable_buf, 10, test_string) from_buf = writable_buf.tostring()[:len(test_string)+10] self.assertEqual(from_buf, test_string[:10] + test_string) # Go beyond boundaries. small_buf = array.array('b', b' '*10) self.assertRaises(struct.error, s.pack_into, small_buf, 0, test_string) self.assertRaises(struct.error, s.pack_into, small_buf, 2, test_string) # Test bogus offset (issue 3694) sb = small_buf self.assertRaises(TypeError, struct.pack_into, b'1', sb, None) def test_pack_into_fn(self): test_string = b'Reykjavik rocks, eow!' writable_buf = array.array('b', b' '*100) fmt = '21s' pack_into = lambda *args: struct.pack_into(fmt, *args) # Test without offset. pack_into(writable_buf, 0, test_string) from_buf = writable_buf.tostring()[:len(test_string)] self.assertEqual(from_buf, test_string) # Test with offset. pack_into(writable_buf, 10, test_string) from_buf = writable_buf.tostring()[:len(test_string)+10] self.assertEqual(from_buf, test_string[:10] + test_string) # Go beyond boundaries. small_buf = array.array('b', b' '*10) self.assertRaises(struct.error, pack_into, small_buf, 0, test_string) self.assertRaises(struct.error, pack_into, small_buf, 2, test_string) def test_unpack_with_buffer(self): # SF bug 1563759: struct.unpack doens't support buffer protocol objects data1 = array.array('B', b'\x12\x34\x56\x78') data2 = memoryview(b'\x12\x34\x56\x78') # XXX b'......XXXX......', 6, 4 for data in [data1, data2]: value, = struct.unpack('>I', data) self.assertEqual(value, 0x12345678) def test_bool(self): for prefix in tuple("<>!=")+('',): false = (), [], [], '', 0 true = [1], 'test', 5, -1, 0xffffffff+1, 0xffffffff/2 falseFormat = prefix + '?' * len(false) packedFalse = struct.pack(falseFormat, *false) unpackedFalse = struct.unpack(falseFormat, packedFalse) trueFormat = prefix + '?' * len(true) packedTrue = struct.pack(trueFormat, *true) unpackedTrue = struct.unpack(trueFormat, packedTrue) self.assertEqual(len(true), len(unpackedTrue)) self.assertEqual(len(false), len(unpackedFalse)) for t in unpackedFalse: self.assertFalse(t) for t in unpackedTrue: self.assertTrue(t) packed = struct.pack(prefix+'?', 1) self.assertEqual(len(packed), struct.calcsize(prefix+'?')) if len(packed) != 1: self.assertFalse(prefix, msg='encoded bool is not one byte: %r' %packed) for c in [b'\x01', b'\x7f', b'\xff', b'\x0f', b'\xf0']: self.assertTrue(struct.unpack('>?', c)[0]) if IS32BIT: def test_crasher(self): self.assertRaises(MemoryError, struct.pack, "357913941b", "a") def test_main(): run_unittest(StructTest) if __name__ == '__main__': test_main()