Lib/test/test_struct.py

   1 from test_support import TestFailed, verbose, verify
   2 import struct
   3 ## import pdb
   4
   5 import sys
   6 ISBIGENDIAN = sys.byteorder == "big"
   7 del sys
   8 verify((struct.pack('=i', 1)[0] == chr(0)) == ISBIGENDIAN,
   9        "bigendian determination appears wrong")
  10
  11 def string_reverse(s):
  12     chars = list(s)
  13     chars.reverse()
  14     return "".join(chars)
  15
  16 def bigendian_to_native(value):
  17     if ISBIGENDIAN:
  18         return value
  19     else:
  20         return string_reverse(value)
  21
  22 def simple_err(func, *args):
  23     try:
  24         apply(func, args)
  25     except struct.error:
  26         pass
  27     else:
  28         raise TestFailed, "%s%s did not raise struct.error" % (
  29             func.__name__, args)
  30 ##      pdb.set_trace()
  31
  32 def any_err(func, *args):
  33     try:
  34         apply(func, args)
  35     except (struct.error, OverflowError, TypeError):
  36         pass
  37     else:
  38         raise TestFailed, "%s%s did not raise error" % (
  39             func.__name__, args)
  40 ##      pdb.set_trace()
  41
  42
  43 simple_err(struct.calcsize, 'Z')
  44
  45 sz = struct.calcsize('i')
  46 if sz * 3 != struct.calcsize('iii'):
  47     raise TestFailed, 'inconsistent sizes'
  48
  49 fmt = 'cbxxxxxxhhhhiillffd'
  50 fmt3 = '3c3b18x12h6i6l6f3d'
  51 sz = struct.calcsize(fmt)
  52 sz3 = struct.calcsize(fmt3)
  53 if sz * 3 != sz3:
  54     raise TestFailed, 'inconsistent sizes (3*%s -> 3*%d = %d, %s -> %d)' % (
  55         `fmt`, sz, 3*sz, `fmt3`, sz3)
  56
  57 simple_err(struct.pack, 'iii', 3)
  58 simple_err(struct.pack, 'i', 3, 3, 3)
  59 simple_err(struct.pack, 'i', 'foo')
  60 simple_err(struct.unpack, 'd', 'flap')
  61 s = struct.pack('ii', 1, 2)
  62 simple_err(struct.unpack, 'iii', s)
  63 simple_err(struct.unpack, 'i', s)
  64
  65 c = 'a'
  66 b = 1
  67 h = 255
  68 i = 65535
  69 l = 65536
  70 f = 3.1415
  71 d = 3.1415
  72
  73 for prefix in ('', '@', '<', '>', '=', '!'):
  74     for format in ('xcbhilfd', 'xcBHILfd'):
  75         format = prefix + format
  76         if verbose:
  77             print "trying:", format
  78         s = struct.pack(format, c, b, h, i, l, f, d)
  79         cp, bp, hp, ip, lp, fp, dp = struct.unpack(format, s)
  80         if (cp != c or bp != b or hp != h or ip != i or lp != l or
  81             int(100 * fp) != int(100 * f) or int(100 * dp) != int(100 * d)):
  82             # ^^^ calculate only to two decimal places
  83             raise TestFailed, "unpack/pack not transitive (%s, %s)" % (
  84                 str(format), str((cp, bp, hp, ip, lp, fp, dp)))
  85
  86 # Test some of the new features in detail
  87
  88 # (format, argument, big-endian result, little-endian result, asymmetric)
  89 tests = [
  90     ('c', 'a', 'a', 'a', 0),
  91     ('xc', 'a', '\0a', '\0a', 0),
  92     ('cx', 'a', 'a\0', 'a\0', 0),
  93     ('s', 'a', 'a', 'a', 0),
  94     ('0s', 'helloworld', '', '', 1),
  95     ('1s', 'helloworld', 'h', 'h', 1),
  96     ('9s', 'helloworld', 'helloworl', 'helloworl', 1),
  97     ('10s', 'helloworld', 'helloworld', 'helloworld', 0),
  98     ('11s', 'helloworld', 'helloworld\0', 'helloworld\0', 1),
  99     ('20s', 'helloworld', 'helloworld'+10*'\0', 'helloworld'+10*'\0', 1),
 100     ('b', 7, '\7', '\7', 0),
 101     ('b', -7, '\371', '\371', 0),
 102     ('B', 7, '\7', '\7', 0),
 103     ('B', 249, '\371', '\371', 0),
 104     ('h', 700, '\002\274', '\274\002', 0),
 105     ('h', -700, '\375D', 'D\375', 0),
 106     ('H', 700, '\002\274', '\274\002', 0),
 107     ('H', 0x10000-700, '\375D', 'D\375', 0),
 108     ('i', 70000000, '\004,\035\200', '\200\035,\004', 0),
 109     ('i', -70000000, '\373\323\342\200', '\200\342\323\373', 0),
 110     ('I', 70000000L, '\004,\035\200', '\200\035,\004', 0),
 111     ('I', 0x100000000L-70000000, '\373\323\342\200', '\200\342\323\373', 0),
 112     ('l', 70000000, '\004,\035\200', '\200\035,\004', 0),
 113     ('l', -70000000, '\373\323\342\200', '\200\342\323\373', 0),
 114     ('L', 70000000L, '\004,\035\200', '\200\035,\004', 0),
 115     ('L', 0x100000000L-70000000, '\373\323\342\200', '\200\342\323\373', 0),
 116     ('f', 2.0, '@\000\000\000', '\000\000\000@', 0),
 117     ('d', 2.0, '@\000\000\000\000\000\000\000',
 118                '\000\000\000\000\000\000\000@', 0),
 119     ('f', -2.0, '\300\000\000\000', '\000\000\000\300', 0),
 120     ('d', -2.0, '\300\000\000\000\000\000\000\000',
 121                '\000\000\000\000\000\000\000\300', 0),
 122 ]
 123
 124 for fmt, arg, big, lil, asy in tests:
 125     if verbose:
 126         print `fmt`, `arg`, `big`, `lil`
 127     for (xfmt, exp) in [('>'+fmt, big), ('!'+fmt, big), ('<'+fmt, lil),
 128                         ('='+fmt, ISBIGENDIAN and big or lil)]:
 129         res = struct.pack(xfmt, arg)
 130         if res != exp:
 131             raise TestFailed, "pack(%s, %s) -> %s # expected %s" % (
 132                 `fmt`, `arg`, `res`, `exp`)
 133         n = struct.calcsize(xfmt)
 134         if n != len(res):
 135             raise TestFailed, "calcsize(%s) -> %d # expected %d" % (
 136                 `xfmt`, n, len(res))
 137         rev = struct.unpack(xfmt, res)[0]
 138         if rev != arg and not asy:
 139             raise TestFailed, "unpack(%s, %s) -> (%s,) # expected (%s,)" % (
 140                 `fmt`, `res`, `rev`, `arg`)
 141
 142 ###########################################################################
 143 # Simple native q/Q tests.
 144
 145 has_native_qQ = 1
 146 try:
 147     struct.pack("q", 5)
 148 except struct.error:
 149     has_native_qQ = 0
 150
 151 if verbose:
 152     print "Platform has native q/Q?", has_native_qQ and "Yes." or "No."
 153
 154 any_err(struct.pack, "Q", -1)   # can't pack -1 as unsigned regardless
 155 simple_err(struct.pack, "q", "a")  # can't pack string as 'q' regardless
 156 simple_err(struct.pack, "Q", "a")  # ditto, but 'Q'
 157
 158 def test_native_qQ():
 159     bytes = struct.calcsize('q')
 160     # The expected values here are in big-endian format, primarily because
 161     # I'm on a little-endian machine and so this is the clearest way (for
 162     # me) to force the code to get exercised.
 163     for format, input, expected in (
 164             ('q', -1, '\xff' * bytes),
 165             ('q', 0, '\x00' * bytes),
 166             ('Q', 0, '\x00' * bytes),
 167             ('q', 1L, '\x00' * (bytes-1) + '\x01'),
 168             ('Q', (1L << (8*bytes))-1, '\xff' * bytes),
 169             ('q', (1L << (8*bytes-1))-1, '\x7f' + '\xff' * (bytes - 1))):
 170         got = struct.pack(format, input)
 171         native_expected = bigendian_to_native(expected)
 172         verify(got == native_expected,
 173                "%r-pack of %r gave %r, not %r" %
 174                     (format, input, got, native_expected))
 175         retrieved = struct.unpack(format, got)[0]
 176         verify(retrieved == input,
 177                "%r-unpack of %r gave %r, not %r" %
 178                     (format, got, retrieved, input))
 179
 180 if has_native_qQ:
 181     test_native_qQ()
 182
 183 ###########################################################################
 184 # Standard integer tests (bBhHiIlLqQ).
 185
 186 import binascii
 187
 188 class IntTester:
 189
 190     # XXX Most std integer modes fail to test for out-of-range.
 191     # The "i" and "l" codes appear to range-check OK on 32-bit boxes, but
 192     # fail to check correctly on some 64-bit ones (Tru64 Unix + Compaq C
 193     # reported by Mark Favas).
 194     BUGGY_RANGE_CHECK = "bBhHiIlL"
 195
 196     def __init__(self, formatpair, bytesize):
 197         assert len(formatpair) == 2
 198         self.formatpair = formatpair
 199         for direction in "<>!=":
 200             for code in formatpair:
 201                 format = direction + code
 202                 verify(struct.calcsize(format) == bytesize)
 203         self.bytesize = bytesize
 204         self.bitsize = bytesize * 8
 205         self.signed_code, self.unsigned_code = formatpair
 206         self.unsigned_min = 0
 207         self.unsigned_max = 2L**self.bitsize - 1
 208         self.signed_min = -(2L**(self.bitsize-1))
 209         self.signed_max = 2L**(self.bitsize-1) - 1
 210
 211     def test_one(self, x, pack=struct.pack,
 212                           unpack=struct.unpack,
 213                           unhexlify=binascii.unhexlify):
 214         if verbose:
 215             print "trying std", self.formatpair, "on", x, "==", hex(x)
 216
 217         # Try signed.
 218         code = self.signed_code
 219         if self.signed_min <= x <= self.signed_max:
 220             # Try big-endian.
 221             expected = long(x)
 222             if x < 0:
 223                 expected += 1L << self.bitsize
 224                 assert expected > 0
 225             expected = hex(expected)[2:-1] # chop "0x" and trailing 'L'
 226             if len(expected) & 1:
 227                 expected = "0" + expected
 228             expected = unhexlify(expected)
 229             expected = "\x00" * (self.bytesize - len(expected)) + expected
 230
 231             # Pack work?
 232             format = ">" + code
 233             got = pack(format, x)
 234             verify(got == expected,
 235                    "'%s'-pack of %r gave %r, not %r" %
 236                     (format, x, got, expected))
 237
 238             # Unpack work?
 239             retrieved = unpack(format, got)[0]
 240             verify(x == retrieved,
 241                    "'%s'-unpack of %r gave %r, not %r" %
 242                     (format, got, retrieved, x))
 243
 244             # Adding any byte should cause a "too big" error.
 245             any_err(unpack, format, '\x01' + got)
 246
 247             # Try little-endian.
 248             format = "<" + code
 249             expected = string_reverse(expected)
 250
 251             # Pack work?
 252             got = pack(format, x)
 253             verify(got == expected,
 254                    "'%s'-pack of %r gave %r, not %r" %
 255                     (format, x, got, expected))
 256
 257             # Unpack work?
 258             retrieved = unpack(format, got)[0]
 259             verify(x == retrieved,
 260                    "'%s'-unpack of %r gave %r, not %r" %
 261                     (format, got, retrieved, x))
 262
 263             # Adding any byte should cause a "too big" error.
 264             any_err(unpack, format, '\x01' + got)
 265
 266         else:
 267             # x is out of range -- verify pack realizes that.
 268             if code in self.BUGGY_RANGE_CHECK:
 269                 if verbose:
 270                     print "Skipping buggy range check for code", code
 271             else:
 272                 any_err(pack, ">" + code, x)
 273                 any_err(pack, "<" + code, x)
 274
 275         # Much the same for unsigned.
 276         code = self.unsigned_code
 277         if self.unsigned_min <= x <= self.unsigned_max:
 278             # Try big-endian.
 279             format = ">" + code
 280             expected = long(x)
 281             expected = hex(expected)[2:-1] # chop "0x" and trailing 'L'
 282             if len(expected) & 1:
 283                 expected = "0" + expected
 284             expected = unhexlify(expected)
 285             expected = "\x00" * (self.bytesize - len(expected)) + expected
 286
 287             # Pack work?
 288             got = pack(format, x)
 289             verify(got == expected,
 290                    "'%s'-pack of %r gave %r, not %r" %
 291                     (format, x, got, expected))
 292
 293             # Unpack work?
 294             retrieved = unpack(format, got)[0]
 295             verify(x == retrieved,
 296                    "'%s'-unpack of %r gave %r, not %r" %
 297                     (format, got, retrieved, x))
 298
 299             # Adding any byte should cause a "too big" error.
 300             any_err(unpack, format, '\x01' + got)
 301
 302             # Try little-endian.
 303             format = "<" + code
 304             expected = string_reverse(expected)
 305
 306             # Pack work?
 307             got = pack(format, x)
 308             verify(got == expected,
 309                    "'%s'-pack of %r gave %r, not %r" %
 310                     (format, x, got, expected))
 311
 312             # Unpack work?
 313             retrieved = unpack(format, got)[0]
 314             verify(x == retrieved,
 315                    "'%s'-unpack of %r gave %r, not %r" %
 316                     (format, got, retrieved, x))
 317
 318             # Adding any byte should cause a "too big" error.
 319             any_err(unpack, format, '\x01' + got)
 320
 321         else:
 322             # x is out of range -- verify pack realizes that.
 323             if code in self.BUGGY_RANGE_CHECK:
 324                 if verbose:
 325                     print "Skipping buggy range check for code", code
 326             else:
 327                 any_err(pack, ">" + code, x)
 328                 any_err(pack, "<" + code, x)
 329
 330     def run(self):
 331         from random import randrange
 332
 333         # Create all interesting powers of 2.
 334         values = []
 335         for exp in range(self.bitsize + 3):
 336             values.append(1L << exp)
 337
 338         # Add some random values.
 339         for i in range(self.bitsize):
 340             val = 0L
 341             for j in range(self.bytesize):
 342                 val = (val << 8) | randrange(256)
 343             values.append(val)
 344
 345         # Try all those, and their negations, and +-1 from them.  Note
 346         # that this tests all power-of-2 boundaries in range, and a few out
 347         # of range, plus +-(2**n +- 1).
 348         for base in values:
 349             for val in -base, base:
 350                 for incr in -1, 0, 1:
 351                     x = val + incr
 352                     try:
 353                         x = int(x)
 354                     except OverflowError:
 355                         pass
 356                     self.test_one(x)
 357
 358         # Some error cases.
 359         for direction in "<>":
 360             for code in self.formatpair:
 361                 for badobject in "a string", 3+42j, randrange:
 362                     any_err(struct.pack, direction + code, badobject)
 363
 364 for args in [("bB", 1),
 365              ("hH", 2),
 366              ("iI", 4),
 367              ("lL", 4),
 368              ("qQ", 8)]:
 369     t = IntTester(*args)
 370     t.run()