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8152d32375
Use != instead of <> since <> is documented as "obsolescent". Use "is" and "is not" when comparing with None or type objects.
280 lines
7.0 KiB
Python
280 lines
7.0 KiB
Python
"""Implements (a subset of) Sun XDR -- eXternal Data Representation.
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See: RFC 1014
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"""
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import struct
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# exceptions
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class Error:
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"""Exception class for this module. Use:
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except xdrlib.Error, var:
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# var has the Error instance for the exception
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Public ivars:
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msg -- contains the message
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"""
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def __init__(self, msg):
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self.msg = msg
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def __repr__(self):
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return repr(self.msg)
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def __str__(self):
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return str(self.msg)
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class ConversionError(Error):
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pass
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class Packer:
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"""Pack various data representations into a buffer."""
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def __init__(self):
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self.reset()
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def reset(self):
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self.__buf = ''
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def get_buffer(self):
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return self.__buf
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# backwards compatibility
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get_buf = get_buffer
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def pack_uint(self, x):
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self.__buf = self.__buf + struct.pack('>L', x)
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pack_int = pack_uint
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pack_enum = pack_int
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def pack_bool(self, x):
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if x: self.__buf = self.__buf + '\0\0\0\1'
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else: self.__buf = self.__buf + '\0\0\0\0'
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def pack_uhyper(self, x):
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self.pack_uint(x>>32 & 0xffffffffL)
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self.pack_uint(x & 0xffffffffL)
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pack_hyper = pack_uhyper
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def pack_float(self, x):
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try: self.__buf = self.__buf + struct.pack('>f', x)
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except struct.error, msg:
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raise ConversionError, msg
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def pack_double(self, x):
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try: self.__buf = self.__buf + struct.pack('>d', x)
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except struct.error, msg:
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raise ConversionError, msg
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def pack_fstring(self, n, s):
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if n < 0:
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raise ValueError, 'fstring size must be nonnegative'
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n = ((n+3)/4)*4
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data = s[:n]
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data = data + (n - len(data)) * '\0'
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self.__buf = self.__buf + data
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pack_fopaque = pack_fstring
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def pack_string(self, s):
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n = len(s)
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self.pack_uint(n)
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self.pack_fstring(n, s)
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pack_opaque = pack_string
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pack_bytes = pack_string
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def pack_list(self, list, pack_item):
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for item in list:
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self.pack_uint(1)
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pack_item(item)
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self.pack_uint(0)
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def pack_farray(self, n, list, pack_item):
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if len(list) != n:
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raise ValueError, 'wrong array size'
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for item in list:
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pack_item(item)
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def pack_array(self, list, pack_item):
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n = len(list)
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self.pack_uint(n)
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self.pack_farray(n, list, pack_item)
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class Unpacker:
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"""Unpacks various data representations from the given buffer."""
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def __init__(self, data):
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self.reset(data)
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def reset(self, data):
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self.__buf = data
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self.__pos = 0
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def get_position(self):
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return self.__pos
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def set_position(self, position):
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self.__pos = position
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def get_buffer(self):
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return self.__buf
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def done(self):
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if self.__pos < len(self.__buf):
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raise Error('unextracted data remains')
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def unpack_uint(self):
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i = self.__pos
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self.__pos = j = i+4
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data = self.__buf[i:j]
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if len(data) < 4:
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raise EOFError
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x = struct.unpack('>L', data)[0]
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try:
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return int(x)
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except OverflowError:
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return x
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def unpack_int(self):
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i = self.__pos
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self.__pos = j = i+4
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data = self.__buf[i:j]
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if len(data) < 4:
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raise EOFError
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return struct.unpack('>l', data)[0]
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unpack_enum = unpack_int
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unpack_bool = unpack_int
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def unpack_uhyper(self):
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hi = self.unpack_uint()
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lo = self.unpack_uint()
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return long(hi)<<32 | lo
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def unpack_hyper(self):
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x = self.unpack_uhyper()
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if x >= 0x8000000000000000L:
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x = x - 0x10000000000000000L
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return x
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def unpack_float(self):
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i = self.__pos
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self.__pos = j = i+4
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data = self.__buf[i:j]
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if len(data) < 4:
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raise EOFError
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return struct.unpack('>f', data)[0]
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def unpack_double(self):
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i = self.__pos
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self.__pos = j = i+8
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data = self.__buf[i:j]
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if len(data) < 8:
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raise EOFError
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return struct.unpack('>d', data)[0]
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def unpack_fstring(self, n):
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if n < 0:
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raise ValueError, 'fstring size must be nonnegative'
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i = self.__pos
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j = i + (n+3)/4*4
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if j > len(self.__buf):
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raise EOFError
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self.__pos = j
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return self.__buf[i:i+n]
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unpack_fopaque = unpack_fstring
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def unpack_string(self):
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n = self.unpack_uint()
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return self.unpack_fstring(n)
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unpack_opaque = unpack_string
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unpack_bytes = unpack_string
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def unpack_list(self, unpack_item):
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list = []
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while 1:
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x = self.unpack_uint()
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if x == 0: break
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if x != 1:
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raise ConversionError, '0 or 1 expected, got ' + `x`
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item = unpack_item()
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list.append(item)
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return list
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def unpack_farray(self, n, unpack_item):
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list = []
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for i in range(n):
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list.append(unpack_item())
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return list
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def unpack_array(self, unpack_item):
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n = self.unpack_uint()
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return self.unpack_farray(n, unpack_item)
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# test suite
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def _test():
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p = Packer()
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packtest = [
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(p.pack_uint, (9,)),
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(p.pack_bool, (None,)),
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(p.pack_bool, ('hello',)),
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(p.pack_uhyper, (45L,)),
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(p.pack_float, (1.9,)),
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(p.pack_double, (1.9,)),
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(p.pack_string, ('hello world',)),
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(p.pack_list, (range(5), p.pack_uint)),
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(p.pack_array, (['what', 'is', 'hapnin', 'doctor'], p.pack_string)),
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]
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succeedlist = [1] * len(packtest)
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count = 0
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for method, args in packtest:
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print 'pack test', count,
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try:
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apply(method, args)
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print 'succeeded'
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except ConversionError, var:
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print 'ConversionError:', var.msg
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succeedlist[count] = 0
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count = count + 1
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data = p.get_buffer()
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# now verify
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up = Unpacker(data)
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unpacktest = [
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(up.unpack_uint, (), lambda x: x == 9),
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(up.unpack_bool, (), lambda x: not x),
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(up.unpack_bool, (), lambda x: x),
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(up.unpack_uhyper, (), lambda x: x == 45L),
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(up.unpack_float, (), lambda x: 1.89 < x < 1.91),
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(up.unpack_double, (), lambda x: 1.89 < x < 1.91),
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(up.unpack_string, (), lambda x: x == 'hello world'),
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(up.unpack_list, (up.unpack_uint,), lambda x: x == range(5)),
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(up.unpack_array, (up.unpack_string,),
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lambda x: x == ['what', 'is', 'hapnin', 'doctor']),
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]
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count = 0
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for method, args, pred in unpacktest:
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print 'unpack test', count,
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try:
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if succeedlist[count]:
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x = apply(method, args)
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print pred(x) and 'succeeded' or 'failed', ':', x
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else:
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print 'skipping'
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except ConversionError, var:
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print 'ConversionError:', var.msg
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count = count + 1
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if __name__ == '__main__':
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_test()
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