protolib.py revision 13540
113819Sgabeblack@google.com#!/usr/bin/env python2.7 213819Sgabeblack@google.com 313819Sgabeblack@google.com# Copyright (c) 2013 ARM Limited 413819Sgabeblack@google.com# All rights reserved 513819Sgabeblack@google.com# 613819Sgabeblack@google.com# The license below extends only to copyright in the software and shall 713819Sgabeblack@google.com# not be construed as granting a license to any other intellectual 813819Sgabeblack@google.com# property including but not limited to intellectual property relating 913819Sgabeblack@google.com# to a hardware implementation of the functionality of the software 1013819Sgabeblack@google.com# licensed hereunder. You may use the software subject to the license 1113819Sgabeblack@google.com# terms below provided that you ensure that this notice is replicated 1213819Sgabeblack@google.com# unmodified and in its entirety in all distributions of the software, 1313819Sgabeblack@google.com# modified or unmodified, in source code or in binary form. 1413819Sgabeblack@google.com# 1513819Sgabeblack@google.com# Redistribution and use in source and binary forms, with or without 1613819Sgabeblack@google.com# modification, are permitted provided that the following conditions are 1713819Sgabeblack@google.com# met: redistributions of source code must retain the above copyright 1813819Sgabeblack@google.com# notice, this list of conditions and the following disclaimer; 1913819Sgabeblack@google.com# redistributions in binary form must reproduce the above copyright 2013819Sgabeblack@google.com# notice, this list of conditions and the following disclaimer in the 2113819Sgabeblack@google.com# documentation and/or other materials provided with the distribution; 2213819Sgabeblack@google.com# neither the name of the copyright holders nor the names of its 2313819Sgabeblack@google.com# contributors may be used to endorse or promote products derived from 2413819Sgabeblack@google.com# this software without specific prior written permission. 2513819Sgabeblack@google.com# 2613819Sgabeblack@google.com# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 2713819Sgabeblack@google.com# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 2813819Sgabeblack@google.com# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 2913819Sgabeblack@google.com# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 3013819Sgabeblack@google.com# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 3113819Sgabeblack@google.com# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 3213819Sgabeblack@google.com# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 3313819Sgabeblack@google.com# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 3413819Sgabeblack@google.com# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 3513819Sgabeblack@google.com# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 3613819Sgabeblack@google.com# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 3713819Sgabeblack@google.com# 3813819Sgabeblack@google.com# Copyright 2008 Google Inc. All rights reserved. 3913819Sgabeblack@google.com# http://code.google.com/p/protobuf/ 4013819Sgabeblack@google.com# 4113819Sgabeblack@google.com# Redistribution and use in source and binary forms, with or without 4213819Sgabeblack@google.com# modification, are permitted provided that the following conditions are 4313819Sgabeblack@google.com# met: 4413819Sgabeblack@google.com# 4513819Sgabeblack@google.com# * Redistributions of source code must retain the above copyright 4613819Sgabeblack@google.com# notice, this list of conditions and the following disclaimer. 4713819Sgabeblack@google.com# * Redistributions in binary form must reproduce the above 4813819Sgabeblack@google.com# copyright notice, this list of conditions and the following disclaimer 4913819Sgabeblack@google.com# in the documentation and/or other materials provided with the 5013819Sgabeblack@google.com# distribution. 5113819Sgabeblack@google.com# * Neither the name of Google Inc. nor the names of its 5213819Sgabeblack@google.com# contributors may be used to endorse or promote products derived from 5313819Sgabeblack@google.com# this software without specific prior written permission. 5413819Sgabeblack@google.com# 5513819Sgabeblack@google.com# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 5613819Sgabeblack@google.com# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 5713819Sgabeblack@google.com# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 5813819Sgabeblack@google.com# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 5913819Sgabeblack@google.com# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 6013819Sgabeblack@google.com# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 6113819Sgabeblack@google.com# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 6213819Sgabeblack@google.com# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 6313819Sgabeblack@google.com# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 6413819Sgabeblack@google.com# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 6513819Sgabeblack@google.com# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 6613819Sgabeblack@google.com# 6713819Sgabeblack@google.com# Authors: Andreas Hansson 6813819Sgabeblack@google.com# Radhika Jagtap 6913819Sgabeblack@google.com 7013819Sgabeblack@google.com# This file is a library of commonly used functions used when interfacing 7113819Sgabeblack@google.com# with protobuf python messages. For eg, the decode scripts for different 7213819Sgabeblack@google.com# types of proto objects can use the same function to decode a single message 7313819Sgabeblack@google.com 7413819Sgabeblack@google.comimport gzip 7513819Sgabeblack@google.comimport struct 7613819Sgabeblack@google.com 7713819Sgabeblack@google.comdef openFileRd(in_file): 7813819Sgabeblack@google.com """ 7913819Sgabeblack@google.com This opens the file passed as argument for reading using an appropriate 8013819Sgabeblack@google.com function depending on if it is gzipped or not. It returns the file 8113819Sgabeblack@google.com handle. 8213819Sgabeblack@google.com """ 8313819Sgabeblack@google.com try: 8413819Sgabeblack@google.com # First see if this file is gzipped 8513819Sgabeblack@google.com try: 8613819Sgabeblack@google.com # Opening the file works even if it is not a gzip file 8713819Sgabeblack@google.com proto_in = gzip.open(in_file, 'rb') 8813819Sgabeblack@google.com 8913819Sgabeblack@google.com # Force a check of the magic number by seeking in the 9013819Sgabeblack@google.com # file. If we do not do it here the error will occur when 9113819Sgabeblack@google.com # reading the first message. 9213819Sgabeblack@google.com proto_in.seek(1) 9313819Sgabeblack@google.com proto_in.seek(0) 9413819Sgabeblack@google.com except IOError: 9513819Sgabeblack@google.com proto_in = open(in_file, 'rb') 9613819Sgabeblack@google.com except IOError: 9713819Sgabeblack@google.com print "Failed to open ", in_file, " for reading" 9813819Sgabeblack@google.com exit(-1) 9913819Sgabeblack@google.com return proto_in 10013819Sgabeblack@google.com 10113819Sgabeblack@google.comdef _DecodeVarint32(in_file): 10213819Sgabeblack@google.com """ 10313819Sgabeblack@google.com The decoding of the Varint32 is copied from 10413819Sgabeblack@google.com google.protobuf.internal.decoder and is only repeated here to 10513819Sgabeblack@google.com avoid depending on the internal functions in the library. If the 10613819Sgabeblack@google.com end of file is reached, return (0, 0). 10713819Sgabeblack@google.com """ 10813819Sgabeblack@google.com result = 0 10913819Sgabeblack@google.com shift = 0 11013819Sgabeblack@google.com pos = 0 11113819Sgabeblack@google.com # Use a 32-bit mask 11213819Sgabeblack@google.com mask = 0xffffffff 11313819Sgabeblack@google.com while 1: 11413819Sgabeblack@google.com c = in_file.read(1) 11513819Sgabeblack@google.com if len(c) == 0: 11613819Sgabeblack@google.com return (0, 0) 11713819Sgabeblack@google.com b = struct.unpack('<B', c)[0] 11813819Sgabeblack@google.com result |= ((b & 0x7f) << shift) 11913819Sgabeblack@google.com pos += 1 12013819Sgabeblack@google.com if not (b & 0x80): 12113819Sgabeblack@google.com if result > 0x7fffffffffffffff: 12213819Sgabeblack@google.com result -= (1 << 64) 12313819Sgabeblack@google.com result |= ~mask 12413819Sgabeblack@google.com else: 125 result &= mask 126 return (result, pos) 127 shift += 7 128 if shift >= 64: 129 raise IOError('Too many bytes when decoding varint.') 130 131def decodeMessage(in_file, message): 132 """ 133 Attempt to read a message from the file and decode it. Return 134 False if no message could be read. 135 """ 136 try: 137 size, pos = _DecodeVarint32(in_file) 138 if size == 0: 139 return False 140 buf = in_file.read(size) 141 message.ParseFromString(buf) 142 return True 143 except IOError: 144 return False 145 146def _EncodeVarint32(out_file, value): 147 """ 148 The encoding of the Varint32 is copied from 149 google.protobuf.internal.encoder and is only repeated here to 150 avoid depending on the internal functions in the library. 151 """ 152 bits = value & 0x7f 153 value >>= 7 154 while value: 155 out_file.write(struct.pack('<B', 0x80 | bits)) 156 bits = value & 0x7f 157 value >>= 7 158 out_file.write(struct.pack('<B', bits)) 159 160def encodeMessage(out_file, message): 161 """ 162 Encoded a message with the length prepended as a 32-bit varint. 163 """ 164 out = message.SerializeToString() 165 _EncodeVarint32(out_file, len(out)) 166 out_file.write(out) 167