src/proto/protoio.cc

   1 /*
   2  * Copyright (c) 2012 ARM Limited
   3  * All rights reserved
   4  *
   5  * The license below extends only to copyright in the software and shall
   6  * not be construed as granting a license to any other intellectual
   7  * property including but not limited to intellectual property relating
   8  * to a hardware implementation of the functionality of the software
   9  * licensed hereunder.  You may use the software subject to the license
  10  * terms below provided that you ensure that this notice is replicated
  11  * unmodified and in its entirety in all distributions of the software,
  12  * modified or unmodified, in source code or in binary form.
  13  *
  14  * Redistribution and use in source and binary forms, with or without
  15  * modification, are permitted provided that the following conditions are
  16  * met: redistributions of source code must retain the above copyright
  17  * notice, this list of conditions and the following disclaimer;
  18  * redistributions in binary form must reproduce the above copyright
  19  * notice, this list of conditions and the following disclaimer in the
  20  * documentation and/or other materials provided with the distribution;
  21  * neither the name of the copyright holders nor the names of its
  22  * contributors may be used to endorse or promote products derived from
  23  * this software without specific prior written permission.
  24  *
  25  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  26  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  27  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  28  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  29  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  30  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  31  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  32  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  33  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  34  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  35  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  36  *
  37  * Authors: Andreas Hansson
  38  */
  39
  40 #include "base/misc.hh"
  41 #include "proto/protoio.hh"
  42
  43 using namespace std;
  44 using namespace google::protobuf;
  45
  46 ProtoOutputStream::ProtoOutputStream(const string& filename) :
  47     fileStream(filename.c_str(), ios::out | ios::binary | ios::trunc),
  48     wrappedFileStream(NULL), gzipStream(NULL), zeroCopyStream(NULL)
  49 {
  50     if (!fileStream.good())
  51         panic("Could not open %s for writing\n", filename);
  52
  53     // Wrap the output file in a zero copy stream, that in turn is
  54     // wrapped in a gzip stream if the filename ends with .gz. The
  55     // latter stream is in turn wrapped in a coded stream
  56     wrappedFileStream = new io::OstreamOutputStream(&fileStream);
  57     if (filename.find_last_of('.') != string::npos &&
  58         filename.substr(filename.find_last_of('.') + 1) == "gz") {
  59         gzipStream = new io::GzipOutputStream(wrappedFileStream);
  60         zeroCopyStream = gzipStream;
  61     } else {
  62         zeroCopyStream = wrappedFileStream;
  63     }
  64
  65     // Write the magic number to the file
  66     io::CodedOutputStream codedStream(zeroCopyStream);
  67     codedStream.WriteLittleEndian32(magicNumber);
  68
  69     // Note that each type of stream (packet, instruction etc) should
  70     // add its own header and perform the appropriate checks
  71 }
  72
  73 ProtoOutputStream::~ProtoOutputStream()
  74 {
  75     // As the compression is optional, see if the stream exists
  76     if (gzipStream != NULL)
  77         delete gzipStream;
  78     delete wrappedFileStream;
  79     fileStream.close();
  80 }
  81
  82 void
  83 ProtoOutputStream::write(const Message& msg)
  84 {
  85     // Due to the byte limit of the coded stream we create it for
  86     // every single mesage (based on forum discussions around the size
  87     // limitation)
  88     io::CodedOutputStream codedStream(zeroCopyStream);
  89
  90     // Write the size of the message to the stream
  91     codedStream.WriteVarint32(msg.ByteSize());
  92
  93     // Write the message itself to the stream
  94     msg.SerializeWithCachedSizes(&codedStream);
  95 }
  96
  97 ProtoInputStream::ProtoInputStream(const string& filename) :
  98     fileStream(filename.c_str(), ios::in | ios::binary), fileName(filename),
  99     useGzip(false),
 100     wrappedFileStream(NULL), gzipStream(NULL), zeroCopyStream(NULL)
 101 {
 102     if (!fileStream.good())
 103         panic("Could not open %s for reading\n", filename);
 104
 105     // check the magic number to see if this is a gzip stream
 106     unsigned char bytes[2];
 107     fileStream.read((char*) bytes, 2);
 108     useGzip = fileStream.good() && bytes[0] == 0x1f && bytes[1] == 0x8b;
 109
 110     // seek to the start of the input file and clear any flags
 111     fileStream.clear();
 112     fileStream.seekg(0, ifstream::beg);
 113
 114     createStreams();
 115 }
 116
 117 void
 118 ProtoInputStream::createStreams()
 119 {
 120     // All streams should be NULL at this point
 121     assert(wrappedFileStream == NULL && gzipStream == NULL &&
 122            zeroCopyStream == NULL);
 123
 124     // Wrap the input file in a zero copy stream, that in turn is
 125     // wrapped in a gzip stream if the filename ends with .gz. The
 126     // latter stream is in turn wrapped in a coded stream
 127     wrappedFileStream = new io::IstreamInputStream(&fileStream);
 128     if (useGzip) {
 129         gzipStream = new io::GzipInputStream(wrappedFileStream);
 130         zeroCopyStream = gzipStream;
 131     } else {
 132         zeroCopyStream = wrappedFileStream;
 133     }
 134
 135     uint32_t magic_check;
 136     io::CodedInputStream codedStream(zeroCopyStream);
 137     if (!codedStream.ReadLittleEndian32(&magic_check) ||
 138         magic_check != magicNumber)
 139         panic("Input file %s is not a valid gem5 proto format.\n",
 140               fileName);
 141 }
 142
 143 void
 144 ProtoInputStream::destroyStreams()
 145 {
 146     // As the compression is optional, see if the stream exists
 147     if (gzipStream != NULL) {
 148         delete gzipStream;
 149         gzipStream = NULL;
 150     }
 151     delete wrappedFileStream;
 152     wrappedFileStream = NULL;
 153
 154     zeroCopyStream = NULL;
 155 }
 156
 157
 158 ProtoInputStream::~ProtoInputStream()
 159 {
 160     destroyStreams();
 161     fileStream.close();
 162 }
 163
 164
 165 void
 166 ProtoInputStream::reset()
 167 {
 168     destroyStreams();
 169     // seek to the start of the input file and clear any flags
 170     fileStream.clear();
 171     fileStream.seekg(0, ifstream::beg);
 172     createStreams();
 173 }
 174
 175 bool
 176 ProtoInputStream::read(Message& msg)
 177 {
 178     // Read a message from the stream by getting the size, using it as
 179     // a limit when parsing the message, then popping the limit again
 180     uint32_t size;
 181
 182     // Due to the byte limit of the coded stream we create it for
 183     // every single mesage (based on forum discussions around the size
 184     // limitation)
 185     io::CodedInputStream codedStream(zeroCopyStream);
 186     if (codedStream.ReadVarint32(&size)) {
 187         io::CodedInputStream::Limit limit = codedStream.PushLimit(size);
 188         if (msg.ParseFromCodedStream(&codedStream)) {
 189             codedStream.PopLimit(limit);
 190             // All went well, the message is parsed and the limit is
 191             // popped again
 192             return true;
 193         } else {
 194             panic("Unable to read message from coded stream %s\n",
 195                   fileName);
 196         }
 197     }
 198
 199     return false;
 200 }