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