protolib.py revision 10107
13914Ssaidi@eecs.umich.edu#!/usr/bin/env python 23914Ssaidi@eecs.umich.edu 33914Ssaidi@eecs.umich.edu# Copyright (c) 2013 ARM Limited 43914Ssaidi@eecs.umich.edu# All rights reserved 53914Ssaidi@eecs.umich.edu# 63914Ssaidi@eecs.umich.edu# The license below extends only to copyright in the software and shall 73914Ssaidi@eecs.umich.edu# not be construed as granting a license to any other intellectual 83914Ssaidi@eecs.umich.edu# property including but not limited to intellectual property relating 93914Ssaidi@eecs.umich.edu# to a hardware implementation of the functionality of the software 103914Ssaidi@eecs.umich.edu# licensed hereunder. You may use the software subject to the license 113914Ssaidi@eecs.umich.edu# terms below provided that you ensure that this notice is replicated 123914Ssaidi@eecs.umich.edu# unmodified and in its entirety in all distributions of the software, 133914Ssaidi@eecs.umich.edu# modified or unmodified, in source code or in binary form. 143914Ssaidi@eecs.umich.edu# 153914Ssaidi@eecs.umich.edu# Redistribution and use in source and binary forms, with or without 163914Ssaidi@eecs.umich.edu# modification, are permitted provided that the following conditions are 173914Ssaidi@eecs.umich.edu# met: redistributions of source code must retain the above copyright 183914Ssaidi@eecs.umich.edu# notice, this list of conditions and the following disclaimer; 193914Ssaidi@eecs.umich.edu# redistributions in binary form must reproduce the above copyright 203914Ssaidi@eecs.umich.edu# notice, this list of conditions and the following disclaimer in the 213914Ssaidi@eecs.umich.edu# documentation and/or other materials provided with the distribution; 223914Ssaidi@eecs.umich.edu# neither the name of the copyright holders nor the names of its 233914Ssaidi@eecs.umich.edu# contributors may be used to endorse or promote products derived from 243914Ssaidi@eecs.umich.edu# this software without specific prior written permission. 253914Ssaidi@eecs.umich.edu# 263914Ssaidi@eecs.umich.edu# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 273914Ssaidi@eecs.umich.edu# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 283914Ssaidi@eecs.umich.edu# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 293914Ssaidi@eecs.umich.edu# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 303914Ssaidi@eecs.umich.edu# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 313914Ssaidi@eecs.umich.edu# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 323914Ssaidi@eecs.umich.edu# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 333914Ssaidi@eecs.umich.edu# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 343914Ssaidi@eecs.umich.edu# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 353914Ssaidi@eecs.umich.edu# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 363914Ssaidi@eecs.umich.edu# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 373914Ssaidi@eecs.umich.edu# 383914Ssaidi@eecs.umich.edu# Copyright 2008 Google Inc. All rights reserved. 393914Ssaidi@eecs.umich.edu# http://code.google.com/p/protobuf/ 403914Ssaidi@eecs.umich.edu# 413914Ssaidi@eecs.umich.edu# Redistribution and use in source and binary forms, with or without 423914Ssaidi@eecs.umich.edu# modification, are permitted provided that the following conditions are 433914Ssaidi@eecs.umich.edu# met: 443914Ssaidi@eecs.umich.edu# 453914Ssaidi@eecs.umich.edu# * Redistributions of source code must retain the above copyright 463914Ssaidi@eecs.umich.edu# notice, this list of conditions and the following disclaimer. 473914Ssaidi@eecs.umich.edu# * Redistributions in binary form must reproduce the above 483914Ssaidi@eecs.umich.edu# copyright notice, this list of conditions and the following disclaimer 493914Ssaidi@eecs.umich.edu# in the documentation and/or other materials provided with the 503914Ssaidi@eecs.umich.edu# distribution. 513914Ssaidi@eecs.umich.edu# * Neither the name of Google Inc. nor the names of its 523943Sbinkertn@umich.edu# contributors may be used to endorse or promote products derived from 533914Ssaidi@eecs.umich.edu# this software without specific prior written permission. 543914Ssaidi@eecs.umich.edu# 553914Ssaidi@eecs.umich.edu# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 563914Ssaidi@eecs.umich.edu# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 573943Sbinkertn@umich.edu# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 583943Sbinkertn@umich.edu# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 593943Sbinkertn@umich.edu# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 603914Ssaidi@eecs.umich.edu# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 613914Ssaidi@eecs.umich.edu# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 623914Ssaidi@eecs.umich.edu# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 633914Ssaidi@eecs.umich.edu# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 643914Ssaidi@eecs.umich.edu# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 653914Ssaidi@eecs.umich.edu# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 663914Ssaidi@eecs.umich.edu# 673914Ssaidi@eecs.umich.edu# Authors: Andreas Hansson 683914Ssaidi@eecs.umich.edu# Radhika Jagtap 693914Ssaidi@eecs.umich.edu 703914Ssaidi@eecs.umich.edu# This file is a library of commonly used functions used when interfacing 713914Ssaidi@eecs.umich.edu# with protobuf python messages. For eg, the decode scripts for different 723914Ssaidi@eecs.umich.edu# types of proto objects can use the same function to decode a single message 733914Ssaidi@eecs.umich.edu 743914Ssaidi@eecs.umich.eduimport struct 753914Ssaidi@eecs.umich.edu 763914Ssaidi@eecs.umich.edudef DecodeVarint(in_file): 773914Ssaidi@eecs.umich.edu """ 783914Ssaidi@eecs.umich.edu The decoding of the Varint32 is copied from 793914Ssaidi@eecs.umich.edu google.protobuf.internal.decoder and is only repeated here to 803914Ssaidi@eecs.umich.edu avoid depending on the internal functions in the library. If the 813914Ssaidi@eecs.umich.edu end of file is reached, return (0, 0). 823914Ssaidi@eecs.umich.edu """ 833914Ssaidi@eecs.umich.edu result = 0 843914Ssaidi@eecs.umich.edu shift = 0 853914Ssaidi@eecs.umich.edu pos = 0 863914Ssaidi@eecs.umich.edu # Use a 32-bit mask 873914Ssaidi@eecs.umich.edu mask = 0xffffffff 883914Ssaidi@eecs.umich.edu while 1: 893914Ssaidi@eecs.umich.edu c = in_file.read(1) 903914Ssaidi@eecs.umich.edu if len(c) == 0: 913943Sbinkertn@umich.edu return (0, 0) 923914Ssaidi@eecs.umich.edu b = struct.unpack('<B', c)[0] 933914Ssaidi@eecs.umich.edu result |= ((b & 0x7f) << shift) 943914Ssaidi@eecs.umich.edu pos += 1 953914Ssaidi@eecs.umich.edu if not (b & 0x80): 963914Ssaidi@eecs.umich.edu if result > 0x7fffffffffffffff: 973914Ssaidi@eecs.umich.edu result -= (1 << 64) 983914Ssaidi@eecs.umich.edu result |= ~mask 993914Ssaidi@eecs.umich.edu else: 1003914Ssaidi@eecs.umich.edu result &= mask 1013943Sbinkertn@umich.edu return (result, pos) 1023914Ssaidi@eecs.umich.edu shift += 7 1033914Ssaidi@eecs.umich.edu if shift >= 64: 1043914Ssaidi@eecs.umich.edu raise IOError('Too many bytes when decoding varint.') 1053914Ssaidi@eecs.umich.edu 1063914Ssaidi@eecs.umich.edudef decodeMessage(in_file, message): 1073914Ssaidi@eecs.umich.edu """ 1083914Ssaidi@eecs.umich.edu Attempt to read a message from the file and decode it. Return 1093914Ssaidi@eecs.umich.edu False if no message could be read. 1103914Ssaidi@eecs.umich.edu """ 1113914Ssaidi@eecs.umich.edu try: 1123914Ssaidi@eecs.umich.edu size, pos = DecodeVarint(in_file) 1133914Ssaidi@eecs.umich.edu if size == 0: 1143914Ssaidi@eecs.umich.edu return False 1153914Ssaidi@eecs.umich.edu buf = in_file.read(size) 1163914Ssaidi@eecs.umich.edu message.ParseFromString(buf) 1173914Ssaidi@eecs.umich.edu return True 118 except IOError: 119 return False 120 121def EncodeVarint(out_file, value): 122 """ 123 The encoding of the Varint32 is copied from 124 google.protobuf.internal.encoder and is only repeated here to 125 avoid depending on the internal functions in the library. 126 """ 127 bits = value & 0x7f 128 value >>= 7 129 while value: 130 out_file.write(struct.pack('<B', 0x80|bits)) 131 bits = value & 0x7f 132 value >>= 7 133 out_file.write(struct.pack('<B', bits)) 134 135def encodeMessage(out_file, message): 136 """ 137 Encoded a message with the length prepended as a 32-bit varint. 138 """ 139 out = message.SerializeToString() 140 EncodeVarint(out_file, len(out)) 141 out_file.write(out) 142