Code Example

struct SomeStruct {
  int a;
  float b;
};
struct AnotherStruct {
  int a;
  double b;
  std::vector<SomeStruct> c;
  std::unordered_map<std::string, uint32_t> d;
  // ....
} another_struct;
// ... set another_struct
std::string str = SerializeToString(another_struct);
if (auto opb = ParseFromString<AnotherStruct>(str)) {
  // *opb is actualy equal to another_struct
}

• See more example example.cpp
• If you want to realize you serialize alothgrim, please refer baseline_serializer and baseline_deserializer

Difference between other serialization

Method	cross-language	modify code needed	container supprot	memory
Troy	by your alothgrim	no	yes	low
Protobuf/Thrift	yes	need to write proto	only vector and map (for proto3)	high
boost serialization	no	yes	no	low
C#.NET framework	only windows	no	yes	low

How To Install

gcc-7.1

• for ubuntu 14.04

sudo add-apt-repository ppa:jonathonf/gcc-7.1

sudo apt-get install gcc-7

• for centos

 yum install gcc-7

• for installation package

install gcc

bazel

• Install JDK 8

• Install JDK 8 by using:

sudo apt-get install openjdk-8-jdk

• On Ubuntu 14.04 LTS you'll have to use a PPA:

sudo add-apt-repository ppa:webupd8team/java

sudo apt-get update && sudo apt-get install oracle-java8-installer

• Add Bazel distribution URI as a package source (one time setup)

echo "deb [arch=amd64] http://storage.googleapis.com/bazel-apt stable jdk1.8" | sudo tee /etc/apt/sources.list.d/bazel.list

curl https://bazel.build/bazel-release.pub.gpg | sudo apt-key add -

If you want to install the testing version of Bazel, replace stable with testing.

• Install and update Bazel

sudo apt-get update && sudo apt-get install bazel

• Once installed, you can upgrade to a newer version of Bazel with:

sudo apt-get upgrade bazel

• More Documents about bazel

• bazel

boost

• for ubuntu 14.04

Run command

sudo apt-get install libboost-all-dev

Or you can call

aptitude search boost

find packages you need and install them using the apt-get command.

• for installation package

install boost

Build And Test

Build

bazel build ...

Test

bazel test ...

Structure of Troy

C++17 Language Features Used in Troy

Template argument deduction for class templates

Automatic template argument deduction much like how it's done for functions, but now including class constructors.

template <typename T = float>
struct MyContainer {
  T val;
  MyContainer() : val() {}
  MyContainer(T val) : val(val) {}
  // ...
};
MyContainer c1{ 1 }; // OK MyContainer<int>
MyContainer c2; // OK MyContainer<float>

Structured bindings

A proposal for de-structuring initialization, that would allow writing auto [ x, y, z ] = expr; where the type of expr was a tuple-like object, whose elements would be bound to the variables x, y, and z (which this construct declares). Tuple-like objects include std::tuple, std::pair, std::array, and aggregate structures.

using Coordinate = std::pair<int, int>;
Coordinate origin() {
  return Coordinate{0, 0};
}
const auto [ x, y ] = origin();
x; // == 0
y; // == 0

Selection statements with initializer

New versions of the if and switch statements which simplify common code patterns and help users keep scopes tight.

{
  std::lock_guard<std::mutex> lk(mx);
  if (v.empty()) v.push_back(val);
}
// vs.
if (std::lock_guard<std::mutex> lk(mx); v.empty()) {
  v.push_back(val);
}

Foo gadget(args);
switch (auto s = gadget.status()) {
  case OK: gadget.zip(); break;
  case Bad: throw BadFoo(s.message());
}
// vs.
switch (Foo gadget(args); auto s = gadget.status()) {
  case OK: gadget.zip(); break;
  case Bad: throw BadFoo(s.message());
}

constexpr if

Write code that is instantiated depending on a compile-time condition.

template <typename T>
constexpr bool isIntegral() {
  if constexpr (std::is_integral<T>::value) {
    return true;
  } else {
    return false;
  }
}
static_assert(isIntegral<int>() == true);
static_assert(isIntegral<char>() == true);
static_assert(isIntegral<double>() == false);
struct S {};
static_assert(isIntegral<S>() == false);

std::optional

The class template std::optional manages an optional contained value, i.e. a value that may or may not be present. A common use case for optional is the return value of a function that may fail.

std::optional<std::string> create(bool b) {
  if (b) {
    return "Godzilla";
  } else {
    return {};
  }
}

Acknowledgements

• cppreference - especially useful for finding examples and documentation of new library features.
• modern-cpp-features modern cpp features for C++11/14/17

Author

Qian Wang(cenrwang@tencent.com)

License

Apache-2.0 license.

TODO

version control

• 版本控制，前向兼容

protobuf / boost::archive alogthiom release

• protobuf 和 boost::archive 算法在troy上的实现

verification interface

• 提供校验接口， 防止文件被污染或错读