| Rich Lane | 15cbe84 | 2013-04-26 16:04:11 -0700 | [diff] [blame^] | 1 | :: # Copyright 2013, Big Switch Networks, Inc. |
| 2 | :: # |
| 3 | :: # LoxiGen is licensed under the Eclipse Public License, version 1.0 (EPL), with |
| 4 | :: # the following special exception: |
| 5 | :: # |
| 6 | :: # LOXI Exception |
| 7 | :: # |
| 8 | :: # As a special exception to the terms of the EPL, you may distribute libraries |
| 9 | :: # generated by LoxiGen (LoxiGen Libraries) under the terms of your choice, provided |
| 10 | :: # that copyright and licensing notices generated by LoxiGen are not altered or removed |
| 11 | :: # from the LoxiGen Libraries and the notice provided below is (i) included in |
| 12 | :: # the LoxiGen Libraries, if distributed in source code form and (ii) included in any |
| 13 | :: # documentation for the LoxiGen Libraries, if distributed in binary form. |
| 14 | :: # |
| 15 | :: # Notice: "Copyright 2013, Big Switch Networks, Inc. This library was generated by the LoxiGen Compiler." |
| 16 | :: # |
| 17 | :: # You may not use this file except in compliance with the EPL or LOXI Exception. You may obtain |
| 18 | :: # a copy of the EPL at: |
| 19 | :: # |
| 20 | :: # http://www.eclipse.org/legal/epl-v10.html |
| 21 | :: # |
| 22 | :: # Unless required by applicable law or agreed to in writing, software |
| 23 | :: # distributed under the License is distributed on an "AS IS" BASIS, WITHOUT |
| 24 | :: # WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the |
| 25 | :: # EPL for the specific language governing permissions and limitations |
| 26 | :: # under the EPL. |
| 27 | :: |
| 28 | :: include('_copyright.py') |
| 29 | """ |
| 30 | Utility functions independent of the protocol version |
| 31 | """ |
| 32 | |
| 33 | :: include('_autogen.py') |
| 34 | |
| 35 | import loxi |
| 36 | import struct |
| 37 | |
| 38 | def unpack_array(deserializer, element_size, buf): |
| 39 | """ |
| 40 | Deserialize an array of fixed length elements. |
| 41 | The deserializer function should take a buffer and return the new object. |
| 42 | """ |
| 43 | if len(buf) % element_size != 0: raise loxi.ProtocolError("invalid array length") |
| 44 | n = len(buf) / element_size |
| 45 | return [deserializer(buffer(buf, i*element_size, element_size)) for i in range(n)] |
| 46 | |
| 47 | def unpack_list(deserializer, length_fmt, buf, extra_len=0): |
| 48 | """ |
| 49 | Deserialize a list of variable-length entries. |
| 50 | 'length_fmt' is a struct format string with exactly one non-padding format |
| 51 | character that returns the length of the given element, minus extra_len. |
| 52 | The deserializer function should take a buffer and return the new object. |
| 53 | """ |
| 54 | entries = [] |
| 55 | offset = 0 |
| 56 | length_struct = struct.Struct(length_fmt) |
| 57 | n = len(buf) |
| 58 | while offset < n: |
| 59 | if offset + length_struct.size > len(buf): raise loxi.ProtocolError("entry header overruns list length") |
| 60 | length, = length_struct.unpack_from(buf, offset) |
| 61 | length += extra_len |
| 62 | if length < length_struct.size: raise loxi.ProtocolError("entry length is less than the header length") |
| 63 | if offset + length > len(buf): raise loxi.ProtocolError("entry length overruns list length") |
| 64 | entries.append(deserializer(buffer(buf, offset, length))) |
| 65 | offset += length |
| 66 | return entries |