1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
|
"""Implements (a subset of) Sun XDR -- eXternal Data Representation.
See: RFC 1014
"""
import struct
try:
from cStringIO import StringIO as _StringIO
except ImportError:
from StringIO import StringIO as _StringIO
from functools import wraps
__all__ = ["Error", "Packer", "Unpacker", "ConversionError"]
# exceptions
class Error(Exception):
"""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
def raise_conversion_error(function):
""" Wrap any raised struct.errors in a ConversionError. """
@wraps(function)
def result(self, value):
try:
return function(self, value)
except struct.error as e:
raise ConversionError(e.args[0])
return result
class Packer:
"""Pack various data representations into a buffer."""
def __init__(self):
self.reset()
def reset(self):
self.__buf = _StringIO()
def get_buffer(self):
return self.__buf.getvalue()
# backwards compatibility
get_buf = get_buffer
@raise_conversion_error
def pack_uint(self, x):
self.__buf.write(struct.pack('>L', x))
@raise_conversion_error
def pack_int(self, x):
self.__buf.write(struct.pack('>l', x))
pack_enum = pack_int
def pack_bool(self, x):
if x: self.__buf.write('\0\0\0\1')
else: self.__buf.write('\0\0\0\0')
def pack_uhyper(self, x):
try:
self.pack_uint(x>>32 & 0xffffffffL)
except (TypeError, struct.error) as e:
raise ConversionError(e.args[0])
try:
self.pack_uint(x & 0xffffffffL)
except (TypeError, struct.error) as e:
raise ConversionError(e.args[0])
pack_hyper = pack_uhyper
@raise_conversion_error
def pack_float(self, x):
self.__buf.write(struct.pack('>f', x))
@raise_conversion_error
def pack_double(self, x):
self.__buf.write(struct.pack('>d', x))
def pack_fstring(self, n, s):
if n < 0:
raise ValueError, 'fstring size must be nonnegative'
data = s[:n]
n = ((n+3)//4)*4
data = data + (n - len(data)) * '\0'
self.__buf.write(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
def unpack_bool(self):
return bool(self.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 %r' % (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)
|
