1 | #!/usr/bin/python |
---|
2 | |
---|
3 | import sys, struct, logging |
---|
4 | from .constants import OutOfBandTags, IntegerTags, OctetStringTags, CharacterStringTags |
---|
5 | |
---|
6 | # initialize logger |
---|
7 | logger = logging.getLogger(__name__) |
---|
8 | |
---|
9 | def setter(prop): |
---|
10 | def f(func): |
---|
11 | return property(prop.fget, func, prop.fdel, prop.__doc__) |
---|
12 | return f |
---|
13 | |
---|
14 | class Value(object): |
---|
15 | """ |
---|
16 | An IPP value consists of a tag and a value. |
---|
17 | |
---|
18 | From RFC 2565: |
---|
19 | ----------------------------------------------- |
---|
20 | | value-tag | 1 byte |
---|
21 | ----------------------------------------------- |
---|
22 | | name-length (value is 0x0000) | 2 bytes |
---|
23 | ----------------------------------------------- |
---|
24 | | value-length (value is v) | 2 bytes |
---|
25 | ----------------------------------------------- |
---|
26 | | value | v bytes |
---|
27 | ----------------------------------------------- |
---|
28 | """ |
---|
29 | |
---|
30 | def __init__(self, value_tag=None, value=None): |
---|
31 | """ |
---|
32 | Initialize a Value. There are three different ways you can |
---|
33 | call this method: |
---|
34 | |
---|
35 | Value() -- creates an empty Value instance |
---|
36 | |
---|
37 | Value(value_tag, value) -- creates a Value instance from |
---|
38 | a non-binary value |
---|
39 | |
---|
40 | If you create an empty Value instance, once you have set |
---|
41 | value_tag and value, you can retrieve the packed value from |
---|
42 | the packed_value property. |
---|
43 | |
---|
44 | Arguments: |
---|
45 | |
---|
46 | value_tag -- one byte, identifying the type of value |
---|
47 | |
---|
48 | value -- variable size, containing the actual value. |
---|
49 | It should be a string or number. |
---|
50 | """ |
---|
51 | |
---|
52 | # make sure the arguments are valid |
---|
53 | if value is not None: |
---|
54 | assert value_tag is not None, \ |
---|
55 | "value_tag must not be null because " + \ |
---|
56 | "value is not null!" |
---|
57 | |
---|
58 | # initialize member variables |
---|
59 | self.value_tag = value_tag # one byte, the type of value |
---|
60 | self.value = value # non-binary value of self.value |
---|
61 | |
---|
62 | @classmethod |
---|
63 | def unpack(cls, value_tag, packed_value): |
---|
64 | """Unpack a binary IPP value |
---|
65 | |
---|
66 | Unpacks a binary string into a Value object. |
---|
67 | |
---|
68 | """ |
---|
69 | return cls(value_tag, cls._unpack(value_tag, packed_value)) |
---|
70 | |
---|
71 | @staticmethod |
---|
72 | def _unpack(value_tag, packed_value): |
---|
73 | """ |
---|
74 | Given self.value_tag and self.packed_value, unpack the binary |
---|
75 | value into either a string or number. These values MUST NOT |
---|
76 | be null. |
---|
77 | |
---|
78 | Returns: unpacked value |
---|
79 | |
---|
80 | """ |
---|
81 | |
---|
82 | assert value_tag is not None, \ |
---|
83 | "Cannot unpack values with unspecified value tag!" |
---|
84 | assert packed_value is not None, \ |
---|
85 | "Cannot unpack null values!" |
---|
86 | |
---|
87 | value = None |
---|
88 | |
---|
89 | # out-of-band value tags |
---|
90 | if value_tag == OutOfBandTags.UNSUPPORTED or \ |
---|
91 | value_tag == OutOfBandTags.DEFAULT or \ |
---|
92 | value_tag == OutOfBandTags.UNKNOWN or \ |
---|
93 | value_tag == OutOfBandTags.NO_VALUE: |
---|
94 | value_size = 0 |
---|
95 | value = '' |
---|
96 | |
---|
97 | # integer value tags |
---|
98 | elif value_tag == IntegerTags.INTEGER: |
---|
99 | value = struct.unpack('>i', packed_value)[0] |
---|
100 | elif value_tag == IntegerTags.BOOLEAN: |
---|
101 | value = struct.unpack('>b', packed_value)[0] |
---|
102 | elif value_tag == IntegerTags.ENUM: |
---|
103 | value = struct.unpack('>i', packed_value)[0] |
---|
104 | |
---|
105 | |
---|
106 | elif value_tag == OctetStringTags.DATETIME: |
---|
107 | # field octets contents range |
---|
108 | # ----- ------ -------- ----- |
---|
109 | # 1 1-2 year 0..65536 |
---|
110 | # 2 3 month 1..12 |
---|
111 | # 3 4 day 1..31 |
---|
112 | # 4 5 hour 0..23 |
---|
113 | # 5 6 minutes 0..59 |
---|
114 | # 6 7 seconds 0..60 |
---|
115 | # (use 60 for leap-second) |
---|
116 | # 7 8 deci-seconds 0..9 |
---|
117 | # 8 9 direction from UTC '+' / '-' |
---|
118 | # 9 10 hours from UTC 0..11 |
---|
119 | # 10 11 minutes from UTC 0..59 |
---|
120 | |
---|
121 | value = struct.unpack('>hbbbbbbcbb', packed_value) |
---|
122 | |
---|
123 | elif value_tag == OctetStringTags.RESOLUTION: |
---|
124 | # OCTET-STRING consisting of nine octets of 2 |
---|
125 | # SIGNED-INTEGERs followed by a SIGNED-BYTE. The first |
---|
126 | # SIGNED-INTEGER contains the value of cross feed |
---|
127 | # direction resolution. The second SIGNED-INTEGER contains |
---|
128 | # the value of feed direction resolution. The SIGNED-BYTE |
---|
129 | # contains the units |
---|
130 | |
---|
131 | value = struct.unpack('>iib', packed_value) |
---|
132 | |
---|
133 | elif value_tag == OctetStringTags.RANGE_OF_INTEGER: |
---|
134 | # Eight octets consisting of 2 SIGNED-INTEGERs. The first |
---|
135 | # SIGNED-INTEGER contains the lower bound and the second |
---|
136 | # SIGNED-INTEGER contains the upper bound. |
---|
137 | |
---|
138 | value = struct.unpack('>ii', packed_value) |
---|
139 | |
---|
140 | elif value_tag == OctetStringTags.TEXT_WITH_LANGUAGE or \ |
---|
141 | value_tag == OctetStringTags.NAME_WITH_LANGUAGE: |
---|
142 | a = struct.unpack('>h', packed_value[:2])[0] |
---|
143 | b = struct.unpack('>%ss' % a, packed_value[2:a+2])[0] |
---|
144 | c = struct.unpack('>h', packed_value[a+2:a+4])[0] |
---|
145 | d = struct.unpack('>%ss' % c, packed_value[a+4:][0]) |
---|
146 | value = (a, b, c, d) |
---|
147 | |
---|
148 | # character string value tags |
---|
149 | elif value_tag == \ |
---|
150 | CharacterStringTags.TEXT_WITHOUT_LANGUAGE or \ |
---|
151 | value_tag == \ |
---|
152 | CharacterStringTags.NAME_WITHOUT_LANGUAGE: |
---|
153 | value = str(packed_value) |
---|
154 | elif value_tag == CharacterStringTags.GENERIC or \ |
---|
155 | value_tag == CharacterStringTags.KEYWORD or \ |
---|
156 | value_tag == CharacterStringTags.URI or \ |
---|
157 | value_tag == CharacterStringTags.URI_SCHEME or \ |
---|
158 | value_tag == CharacterStringTags.CHARSET or \ |
---|
159 | value_tag == CharacterStringTags.NATURAL_LANGUAGE or \ |
---|
160 | value_tag == CharacterStringTags.MIME_MEDIA_TYPE: |
---|
161 | value = str(packed_value) |
---|
162 | |
---|
163 | # anything else that we didn't handle |
---|
164 | else: |
---|
165 | if value is None: |
---|
166 | value = packed_value |
---|
167 | |
---|
168 | return value |
---|
169 | |
---|
170 | @property |
---|
171 | def packed_value(self): |
---|
172 | """ |
---|
173 | Given self.value_tag and self.value, pack the value into |
---|
174 | binary form. These values MUST NOT be null. |
---|
175 | |
---|
176 | Returns: packed_value |
---|
177 | |
---|
178 | """ |
---|
179 | |
---|
180 | assert self.value_tag is not None, \ |
---|
181 | "cannot pack value with null value tag!" |
---|
182 | assert self.value is not None, \ |
---|
183 | "cannot pack null value!" |
---|
184 | |
---|
185 | packed_value = None |
---|
186 | |
---|
187 | # out-of-band value tags |
---|
188 | if self.value_tag == OutOfBandTags.UNSUPPORTED or \ |
---|
189 | self.value_tag == OutOfBandTags.DEFAULT or \ |
---|
190 | self.value_tag == OutOfBandTags.UNKNOWN or \ |
---|
191 | self.value_tag == OutOfBandTags.NO_VALUE: |
---|
192 | packed_value = '' |
---|
193 | |
---|
194 | # integer value tags |
---|
195 | elif self.value_tag == IntegerTags.INTEGER: |
---|
196 | packed_value = struct.pack('>i', self.value) |
---|
197 | elif self.value_tag == IntegerTags.BOOLEAN: |
---|
198 | packed_value = struct.pack('>b', self.value) |
---|
199 | elif self.value_tag == IntegerTags.ENUM: |
---|
200 | packed_value = struct.pack('>i', self.value) |
---|
201 | |
---|
202 | # octet string value tags |
---|
203 | elif self.value_tag == OctetStringTags.DATETIME: |
---|
204 | # field octets contents range |
---|
205 | # ----- ------ -------- ----- |
---|
206 | # 1 1-2 year 0..65536 |
---|
207 | # 2 3 month 1..12 |
---|
208 | # 3 4 day 1..31 |
---|
209 | # 4 5 hour 0..23 |
---|
210 | # 5 6 minutes 0..59 |
---|
211 | # 6 7 seconds 0..60 |
---|
212 | # (use 60 for leap-second) |
---|
213 | # 7 8 deci-seconds 0..9 |
---|
214 | # 8 9 direction from UTC '+' / '-' |
---|
215 | # 9 10 hours from UTC 0..11 |
---|
216 | # 10 11 minutes from UTC 0..59 |
---|
217 | |
---|
218 | packed_value = struct.pack('>hbbbbbbcbb', *self.value) |
---|
219 | |
---|
220 | elif self.value_tag == OctetStringTags.RESOLUTION: |
---|
221 | # OCTET-STRING consisting of nine octets of 2 |
---|
222 | # SIGNED-INTEGERs followed by a SIGNED-BYTE. The first |
---|
223 | # SIGNED-INTEGER contains the value of cross feed |
---|
224 | # direction resolution. The second SIGNED-INTEGER contains |
---|
225 | # the value of feed direction resolution. The SIGNED-BYTE |
---|
226 | # contains the units |
---|
227 | |
---|
228 | packed_value = truct.pack('>iib', self.value) |
---|
229 | |
---|
230 | elif self.value_tag == OctetStringTags.RANGE_OF_INTEGER: |
---|
231 | # Eight octets consisting of 2 SIGNED-INTEGERs. The first |
---|
232 | # SIGNED-INTEGER contains the lower bound and the second |
---|
233 | # SIGNED-INTEGER contains the upper bound. |
---|
234 | |
---|
235 | packed_value = struct.pack('>ii', self.value) |
---|
236 | |
---|
237 | elif self.value_tag == OctetStringTags.TEXT_WITH_LANGUAGE or \ |
---|
238 | self.value_tag == OctetStringTags.NAME_WITH_LANGUAGE: |
---|
239 | |
---|
240 | a_bin = struct.pack('>h', self.value[0]) |
---|
241 | b_bin = struct.pack('>%ss' % self.value[0], self.value[1]) |
---|
242 | c_bin = struct.pack('>h', self.value[2]) |
---|
243 | d_bin = struct.pack('>%ss' % self.value[2], self.value[3]) |
---|
244 | |
---|
245 | packed_value = a_bin + b_bin + c_bin + d_bin |
---|
246 | |
---|
247 | # character string value tags |
---|
248 | elif self.value_tag == \ |
---|
249 | CharacterStringTags.TEXT_WITHOUT_LANGUAGE or \ |
---|
250 | self.value_tag == \ |
---|
251 | CharacterStringTags.NAME_WITHOUT_LANGUAGE: |
---|
252 | |
---|
253 | packed_value = struct.pack('>%ss' % len(self.value), |
---|
254 | self.value) |
---|
255 | |
---|
256 | elif self.value_tag == CharacterStringTags.GENERIC or \ |
---|
257 | self.value_tag == CharacterStringTags.KEYWORD or \ |
---|
258 | self.value_tag == CharacterStringTags.URI or \ |
---|
259 | self.value_tag == CharacterStringTags.URI_SCHEME or \ |
---|
260 | self.value_tag == CharacterStringTags.CHARSET or \ |
---|
261 | self.value_tag == CharacterStringTags.NATURAL_LANGUAGE or \ |
---|
262 | self.value_tag == CharacterStringTags.MIME_MEDIA_TYPE: |
---|
263 | |
---|
264 | packed_value = struct.pack('>%ss' % len(self.value), |
---|
265 | self.value) |
---|
266 | |
---|
267 | else: |
---|
268 | packed_value = self.value |
---|
269 | |
---|
270 | return packed_value |
---|
271 | |
---|
272 | @setter(packed_value) |
---|
273 | def packed_value(self, packed_value): |
---|
274 | """Replace a value using a new packed value |
---|
275 | |
---|
276 | Unpacks a new packed_value (of the same value_tag). |
---|
277 | |
---|
278 | """ |
---|
279 | self.value = self._unpack(self.value_tag, packed_value) |
---|
280 | |
---|
281 | @property |
---|
282 | def packed_value_size(self): |
---|
283 | """ |
---|
284 | Get the size of the value in bytes. |
---|
285 | """ |
---|
286 | |
---|
287 | return len(self.packed_value) |
---|
288 | |
---|
289 | @property |
---|
290 | def total_size(self): |
---|
291 | """ |
---|
292 | Get the total size of the IPP value. |
---|
293 | """ |
---|
294 | |
---|
295 | # 1 byte for the tag |
---|
296 | return self.packed_value_size + 1 |
---|
297 | |
---|
298 | def __str__(self): |
---|
299 | return str(self.value) |
---|
300 | |
---|
301 | def __repr__(self): |
---|
302 | return '<IPPValue (%r, %r)>' % (self.value_tag, self.value) |
---|