/Lib/test/test_struct.py
http://unladen-swallow.googlecode.com/ · Python · 590 lines · 440 code · 83 blank · 67 comment · 81 complexity · d2bceef34c3357b8d1795ed2b69000a6 MD5 · raw file
- import array
- import unittest
- import struct
- import warnings
- warnings.filterwarnings("ignore", "struct integer overflow masking is deprecated",
- DeprecationWarning)
- from functools import wraps
- from test.test_support import TestFailed, verbose, run_unittest
- import sys
- ISBIGENDIAN = sys.byteorder == "big"
- IS32BIT = sys.maxsize == 0x7fffffff
- del sys
- try:
- import _struct
- except ImportError:
- PY_STRUCT_RANGE_CHECKING = 0
- PY_STRUCT_OVERFLOW_MASKING = 1
- PY_STRUCT_FLOAT_COERCE = 2
- else:
- PY_STRUCT_RANGE_CHECKING = getattr(_struct, '_PY_STRUCT_RANGE_CHECKING', 0)
- PY_STRUCT_OVERFLOW_MASKING = getattr(_struct, '_PY_STRUCT_OVERFLOW_MASKING', 0)
- PY_STRUCT_FLOAT_COERCE = getattr(_struct, '_PY_STRUCT_FLOAT_COERCE', 0)
- def string_reverse(s):
- return "".join(reversed(s))
- def bigendian_to_native(value):
- if ISBIGENDIAN:
- return value
- else:
- return string_reverse(value)
- def with_warning_restore(func):
- @wraps(func)
- def decorator(*args, **kw):
- with warnings.catch_warnings():
- # We need this function to warn every time, so stick an
- # unqualifed 'always' at the head of the filter list
- warnings.simplefilter("always")
- warnings.filterwarnings("error", category=DeprecationWarning)
- return func(*args, **kw)
- return decorator
- @with_warning_restore
- def deprecated_err(func, *args):
- try:
- func(*args)
- except (struct.error, TypeError):
- pass
- except DeprecationWarning:
- if not PY_STRUCT_OVERFLOW_MASKING:
- raise TestFailed, "%s%s expected to raise DeprecationWarning" % (
- func.__name__, args)
- else:
- raise TestFailed, "%s%s did not raise error" % (
- func.__name__, args)
- class StructTest(unittest.TestCase):
- @with_warning_restore
- def check_float_coerce(self, format, number):
- # SF bug 1530559. struct.pack raises TypeError where it used to convert.
- if PY_STRUCT_FLOAT_COERCE == 2:
- # Test for pre-2.5 struct module
- packed = struct.pack(format, number)
- floored = struct.unpack(format, packed)[0]
- self.assertEqual(floored, int(number),
- "did not correcly coerce float to int")
- return
- try:
- struct.pack(format, number)
- except (struct.error, TypeError):
- if PY_STRUCT_FLOAT_COERCE:
- self.fail("expected DeprecationWarning for float coerce")
- except DeprecationWarning:
- if not PY_STRUCT_FLOAT_COERCE:
- self.fail("expected to raise struct.error for float coerce")
- else:
- self.fail("did not raise error for float coerce")
- def test_isbigendian(self):
- self.assertEqual((struct.pack('=i', 1)[0] == chr(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', '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 = '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', 70000000L, '\004,\035\200', '\200\035,\004', 0),
- ('I', 0x100000000L-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', 70000000L, '\004,\035\200', '\200\035,\004', 0),
- ('L', 0x100000000L-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:
- 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 rev != arg:
- self.assert_(asy)
- def test_native_qQ(self):
- # can't pack -1 as unsigned regardless
- self.assertRaises((struct.error, TypeError), 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:
- bytes = 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' * bytes),
- ('q', 0, '\x00' * bytes),
- ('Q', 0, '\x00' * bytes),
- ('q', 1L, '\x00' * (bytes-1) + '\x01'),
- ('Q', (1L << (8*bytes))-1, '\xff' * bytes),
- ('q', (1L << (8*bytes-1))-1, '\x7f' + '\xff' * (bytes - 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):
- # XXX Most std integer modes fail to test for out-of-range.
- # The "i" and "l" codes appear to range-check OK on 32-bit boxes, but
- # fail to check correctly on some 64-bit ones (Tru64 Unix + Compaq C
- # reported by Mark Favas).
- BUGGY_RANGE_CHECK = "bBhHiIlL"
- def __init__(self, formatpair, bytesize):
- 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 = 2L**self.bitsize - 1
- self.signed_min = -(2L**(self.bitsize-1))
- self.signed_max = 2L**(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 = long(x)
- if x < 0:
- expected += 1L << self.bitsize
- self.assert_(expected > 0)
- expected = hex(expected)[2:-1] # chop "0x" and trailing 'L'
- if len(expected) & 1:
- expected = "0" + expected
- expected = unhexlify(expected)
- expected = "\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,
- '\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,
- '\x01' + got)
- else:
- # x is out of range -- verify pack realizes that.
- if not PY_STRUCT_RANGE_CHECKING and code in self.BUGGY_RANGE_CHECK:
- if verbose:
- print "Skipping buggy range check for code", code
- else:
- deprecated_err(pack, ">" + code, x)
- deprecated_err(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 = long(x)
- expected = hex(expected)[2:-1] # chop "0x" and trailing 'L'
- if len(expected) & 1:
- expected = "0" + expected
- expected = unhexlify(expected)
- expected = "\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,
- '\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,
- '\x01' + got)
- else:
- # x is out of range -- verify pack realizes that.
- if not PY_STRUCT_RANGE_CHECKING and code in self.BUGGY_RANGE_CHECK:
- if verbose:
- print "Skipping buggy range check for code", code
- else:
- deprecated_err(pack, ">" + code, x)
- deprecated_err(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(1L << exp)
- # Add some random values.
- for i in range(self.bitsize):
- val = 0L
- 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:
- self.assertRaises((struct.error, TypeError),
- 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', ''),
- ('1p', 'abc', '\x00', ''),
- ('2p', 'abc', '\x01a', 'a'),
- ('3p', 'abc', '\x02ab', 'ab'),
- ('4p', 'abc', '\x03abc', 'abc'),
- ('5p', 'abc', '\x03abc\x00', 'abc'),
- ('6p', 'abc', '\x03abc\x00\x00', 'abc'),
- ('1000p', 'x'*1000, '\xff' + 'x'*999, 'x'*255)]:
- 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" and ">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)
- unpacked = struct.unpack("<f", packed)[0]
- # This failed at base = 2, 4, and 32, with unpacked = 1, 2, and
- # 16, respectively.
- self.assertEqual(base, unpacked)
- bigpacked = 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)
- if PY_STRUCT_RANGE_CHECKING:
- def test_1229380(self):
- # SF bug 1229380. No struct.pack exception for some out of
- # range integers
- import sys
- for endian in ('', '>', '<'):
- for cls in (int, long):
- for fmt in ('B', 'H', 'I', 'L'):
- deprecated_err(struct.pack, endian + fmt, cls(-1))
- deprecated_err(struct.pack, endian + 'B', cls(300))
- deprecated_err(struct.pack, endian + 'H', cls(70000))
- deprecated_err(struct.pack, endian + 'I', sys.maxint * 4L)
- deprecated_err(struct.pack, endian + 'L', sys.maxint * 4L)
- def XXXtest_1530559(self):
- # XXX This is broken: see the bug report
- # SF bug 1530559. struct.pack raises TypeError where it used to convert.
- for endian in ('', '>', '<'):
- for fmt in ('B', 'H', 'I', 'L', 'b', 'h', 'i', 'l'):
- self.check_float_coerce(endian + fmt, 1.0)
- self.check_float_coerce(endian + fmt, 1.5)
- def test_issue4228(self):
- # Packing a long may yield either 32 or 64 bits
- x = struct.pack('L', -1)[:4]
- self.assertEqual(x, '\xff'*4)
- def test_unpack_from(self):
- test_string = 'abcd01234'
- fmt = '4s'
- s = struct.Struct(fmt)
- for cls in (str, buffer):
- data = cls(test_string)
- self.assertEqual(s.unpack_from(data), ('abcd',))
- self.assertEqual(s.unpack_from(data, 2), ('cd01',))
- self.assertEqual(s.unpack_from(data, 4), ('0123',))
- for i in xrange(6):
- self.assertEqual(s.unpack_from(data, i), (data[i:i+4],))
- for i in xrange(6, len(test_string) + 1):
- self.assertRaises(struct.error, s.unpack_from, data, i)
- for cls in (str, buffer):
- data = cls(test_string)
- self.assertEqual(struct.unpack_from(fmt, data), ('abcd',))
- self.assertEqual(struct.unpack_from(fmt, data, 2), ('cd01',))
- self.assertEqual(struct.unpack_from(fmt, data, 4), ('0123',))
- for i in xrange(6):
- self.assertEqual(struct.unpack_from(fmt, data, i), (data[i:i+4],))
- for i in xrange(6, len(test_string) + 1):
- self.assertRaises(struct.error, struct.unpack_from, fmt, data, i)
- def test_pack_into(self):
- test_string = 'Reykjavik rocks, eow!'
- writable_buf = array.array('c', ' '*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('c', ' '*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 = 'Reykjavik rocks, eow!'
- writable_buf = array.array('c', ' '*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('c', ' '*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', '\x12\x34\x56\x78')
- data2 = buffer('......\x12\x34\x56\x78......', 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, 0xffffffffL+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 '\x01\x7f\xff\x0f\xf0':
- self.assertTrue(struct.unpack('>?', c)[0])
- if IS32BIT:
- def test_crasher(self):
- self.assertRaises(MemoryError, struct.pack, "357913941c", "a")
- def test_main():
- run_unittest(StructTest)
- if __name__ == '__main__':
- test_main()