1UNPACK(3) unpack 2.4 UNPACK(3)
2
6 packet.unpack - Unpack module
7
9 Provides the object for managing and unpacking raw data from a working
10 buffer.
11
13 class Unpack(__builtin__.object)
14 Unpack object
15 Usage:
17 from packet.unpack import Unpack
18 x = Unpack(buffer)
20 # Get 32 bytes from the working buffer and move the offset pointer
22 data = x.read(32)
23 # Get all the unprocessed bytes from the working buffer
25 # (all bytes starting from the offset pointer)
26 # Do not move the offset pointer
27 data = x.getbytes()
28 # Get all bytes from the working buffer from the given offset
30 # Do not move the offset pointer
31 data = x.getbytes(offset)
32 # Return the number of unprocessed bytes left in the working buffer
34 size = x.size()
35 size = len(x)
36 # Get the offset pointer
38 offset = x.tell()
39 # Set the offset pointer
41 x.seek(offset)
42 # Append the given data to the working buffer
44 x.append(data)
45 # Insert the given data to the working buffer right before the
47 # offset pointer. This resets the working buffer completely
48 # and the offset pointer is initialized to zero. It is like
49 # re-instantiating the object like:
50 # x = Unpack(data + x.getbytes())
51 x.insert(data)
52 # Save state
54 sid = x.save_state()
55 # Restore state
57 x.restore_state(sid)
58 # Unpack an 'unsigned short' (2 bytes in network order)
60 short_int = x.unpack(2, '!H')[0]
61 # Unpack different basic types
63 char = x.unpack_char()
64 uchar = x.unpack_uchar()
65 short = x.unpack_short()
66 ushort = x.unpack_ushort()
67 int = x.unpack_int()
68 uint = x.unpack_uint()
69 int64 = x.unpack_int64()
70 uint64 = x.unpack_uint64()
71 data1 = x.unpack_opaque()
72 data2 = x.unpack_opaque(64) # Length of opaque must be <= 64
73 data3 = x.unpack_fopaque(32)
74 # Get string where length is given as an unsigned integer
76 buffer = x.unpack_string()
77 # Get string of fixed length
78 buffer = x.unpack_string(32)
79 # Get string where length is given as a short integer
80 buffer = x.unpack_string(Unpack.unpack_short)
81 buffer = x.unpack_string(ltype=Unpack.unpack_short)
82 # Get string padded to a 4 byte boundary, discard padding bytes
83 buffer = x.unpack_string(pad=4)
84 # Get an array of unsigned integers
86 alist = x.unpack_array()
87 # Get a fixed length array of unsigned integers
88 alist = x.unpack_array(ltype=10)
89 # Get an array of short integers
90 alist = x.unpack_array(Unpack.unpack_short)
91 # Get an array of strings, the length of the array is given
92 # by a short integer
93 alist = x.unpack_array(Unpack.unpack_string, Unpack.unpack_short)
94 # Get an array of strings, the length of each string is given by
95 # a short integer and each string is padded to a 4 byte boundary
96 alist = x.unpack_array(Unpack.unpack_string, uargs={'ltype':Unpack.unpack_short, 'pad':4})
97 # Get an array of objects decoded by item_obj where the first
98 # argument to item_obj is the unpack object, e.g., item = item_obj(x)
99 alist = x.unpack_array(item_obj)
100 # Get a list of unsigned integers
102 alist = x.unpack_list()
103 # Get a list of short integers
104 alist = x.unpack_list(Unpack.unpack_short)
105 # Get a list of strings, the next item flag is given
106 # by a short integer
107 alist = x.unpack_list(Unpack.unpack_string, Unpack.unpack_short)
108 # Get a list of strings, the length of each string is given by
109 # a short integer and each string is padded to a 4 byte boundary
110 alist = x.unpack_list(Unpack.unpack_string, uargs={'ltype':Unpack.unpack_short, 'pad':4})
111 # Unpack a conditional, it unpacks a conditional flag first and
113 # if it is true it unpacks the item given and returns it. If the
114 # conditional flag decoded is false, the method returns None
115 buffer = x.unpack_conditional(Unpack.unpack_opaque)
116 # Unpack an array of unsigned integers and convert array into
118 # a single long integer
119 bitmask = unpack_bitmap()
120 Methods defined here:
123 ---------------------
124 __init__(self, data)
126 Constructor
127 Initialize object's private data.
129 data: Raw packet data
132 __len__ = size(self)
134 append(self, data)
136 Append data to the working buffer.
137 getbytes(self, offset=None)
139 Get the number of bytes given from the working buffer.
140 Do not move the offset pointer.
141 offset:
144 Starting offset of data to return [default: current offset]
145 insert(self, data)
147 Insert data to the beginning of the current working buffer.
148 read(self, size, pad=0)
150 Get the number of bytes given from the working buffer.
151 Move the offset pointer.
152 size: Length of data to get
155 pad: Get and discard padding bytes [default: 0]
157 If given, data is padded to this byte boundary
158 restore_state(self, sid)
160 Restore state given by the state id
161 save_state(self)
163 Save state and return the state id
164 seek(self, offset)
166 Set the offset pointer.
167 size(self)
169 Return the number of unprocessed bytes left in the working buffer
170 tell(self)
172 Get the offset pointer.
173 unpack(self, size, fmt)
175 Get the number of bytes given from the working buffer and process
176 it according to the given format.
177 Return a tuple of unpack items, see struct.unpack.
178 size: Length of data to process
181 fmt: Format string on how to process data
183 unpack_array(self, unpack_item=<function unpack_uint>, ltype=<function unpack_uint>, uargs={}, maxcount=0, islist=False)
185 Get a variable length array, the type of objects in the array
186 is given by the unpacking function unpack_item and the type
187 to decode the length of the array is given by ltype
188 unpack_item:
191 Unpack function for each item in the array [default: unpack_uint]
192 ltype: Function to decode length of array [default: unpack_uint]
194 Could also be given as an integer to have a fixed length array
195 uargs: Named arguments to pass to unpack_item function [default: {}]
197 maxcount:
199 Maximum length of array [default: any length]
200 unpack_bitmap(self)
202 Unpack an array of unsigned integers and convert array into
203 a single long integer
204 unpack_char(self)
206 Get a signed char
207 unpack_conditional(self, unpack_item=<function unpack_uint>, ltype=<function unpack_uint>, uargs={})
209 Get an item if condition flag given by ltype is true, if condition
210 flag is false then return None
211 unpack_item:
214 Unpack function for item if condition is true [default: unpack_uint]
215 ltype: Function to decode the condition flag [default: unpack_uint]
217 uargs: Named arguments to pass to unpack_item function [default: {}]
219 unpack_fopaque(self, size)
221 Get a fixed length opaque
222 unpack_int(self)
224 Get a signed integer
225 unpack_int64(self)
227 Get a signed 64 bit integer
228 unpack_list(self, *kwts, **kwds)
230 Get an indeterminate size list, the type of objects in the list
231 is given by the unpacking function unpack_item and the type
232 to decode the next item flag is given by ltype
233 unpack_item:
236 Unpack function for each item in the list [default: unpack_uint]
237 ltype: Function to decode the next item flag [default: unpack_uint]
239 uargs: Named arguments to pass to unpack_item function [default: {}]
241 unpack_opaque(self, maxcount=0)
243 Get a variable length opaque up to a maximum length of maxcount
244 unpack_short(self)
246 Get a signed short integer
247 unpack_string(self, ltype=<function unpack_uint>, pad=0, maxcount=0)
249 Get a variable length string
250 ltype: Function to decode length of string [default: unpack_uint]
253 Could also be given as an integer to have a fixed length string
254 pad: Get and discard padding bytes [default: 0]
256 If given, string is padded to this byte boundary
257 maxcount:
259 Maximum length of string [default: any length]
260 unpack_uchar(self)
262 Get an unsigned char
263 unpack_uint(self)
265 Get an unsigned integer
266 unpack_uint64(self)
268 Get an unsigned 64 bit integer
269 unpack_ushort(self)
271 Get an unsigned short integer
272
274 No known bugs.
275
277 Jorge Mora (mora@netapp.com)
278NFStest 2.1.5 14 February 2017 UNPACK(3)