Sematic-Cartographer/cartographer-master/cartographer/io/proto_stream.cc

101 lines
2.9 KiB
C++
Executable File

/*
* Copyright 2016 The Cartographer Authors
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "cartographer/io/proto_stream.h"
#include "glog/logging.h"
namespace cartographer {
namespace io {
namespace {
// First eight bytes to identify our proto stream format.
const uint64 kMagic = 0x7b1d1f7b5bf501db;
void WriteSizeAsLittleEndian(uint64 size, std::ostream* out) {
for (int i = 0; i != 8; ++i) {
out->put(size & 0xff);
size >>= 8;
}
}
bool ReadSizeAsLittleEndian(std::istream* in, uint64* size) {
*size = 0;
for (int i = 0; i != 8; ++i) {
*size >>= 8;
*size += static_cast<uint64>(in->get()) << 56;
}
return !in->fail();
}
} // namespace
ProtoStreamWriter::ProtoStreamWriter(const std::string& filename)
: out_(filename, std::ios::out | std::ios::binary) {
WriteSizeAsLittleEndian(kMagic, &out_);
}
void ProtoStreamWriter::Write(const std::string& uncompressed_data) {
std::string compressed_data;
common::FastGzipString(uncompressed_data, &compressed_data);
WriteSizeAsLittleEndian(compressed_data.size(), &out_);
out_.write(compressed_data.data(), compressed_data.size());
}
void ProtoStreamWriter::WriteProto(const google::protobuf::Message& proto) {
std::string uncompressed_data;
proto.SerializeToString(&uncompressed_data);
Write(uncompressed_data);
}
bool ProtoStreamWriter::Close() {
out_.close();
return !out_.fail();
}
ProtoStreamReader::ProtoStreamReader(const std::string& filename)
: in_(filename, std::ios::in | std::ios::binary) {
uint64 magic;
if (!ReadSizeAsLittleEndian(&in_, &magic) || magic != kMagic) {
in_.setstate(std::ios::failbit);
}
CHECK(in_.good()) << "Failed to open proto stream '" << filename << "'.";
}
bool ProtoStreamReader::Read(std::string* decompressed_data) {
uint64 compressed_size;
if (!ReadSizeAsLittleEndian(&in_, &compressed_size)) {
return false;
}
std::string compressed_data(compressed_size, '\0');
if (!in_.read(&compressed_data.front(), compressed_size)) {
return false;
}
common::FastGunzipString(compressed_data, decompressed_data);
return true;
}
bool ProtoStreamReader::ReadProto(google::protobuf::Message* proto) {
std::string decompressed_data;
return Read(&decompressed_data) && proto->ParseFromString(decompressed_data);
}
bool ProtoStreamReader::eof() const { return in_.eof(); }
} // namespace io
} // namespace cartographer