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https://github.com/felixguendling/cista

Cista is a simple, high-performance, zero-copy C++ serialization & reflection library.
https://github.com/felixguendling/cista

benchmark cpp cpp17 deserialization efficient high-performance reflection serialization zero-copy

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Cista is a simple, high-performance, zero-copy C++ serialization & reflection library.

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# Simple C++ Serialization & Reflection.



Cista++ is a simple, open source (MIT license) C++17 compatible way of (de-)serializing C++ data structures.



*Single header - no dependencies. No macros. No source code generation.*



  - Raw performance - use your native structs. Supports modification/resizing of deserialized data!

  - Supports complex and cyclic data structures including cyclic references, recursive data structures, etc.

  - Save 50% memory: serialize directly to the filesystem if needed, no intermediate buffer required.

  - Fuzzing-checked though continuous fuzzing using LLVMs LibFuzzer.

  - Comes with a serializable high-performance hash map and hash set implementation based on [Google's Swiss Table](https://abseil.io/blog/20180927-swisstables).

  - Reduce boilerplate code: automatic derivation of hash and equality functions.

  - Built-in optional automatic data structure versioning through recursive type hashing.

  - Optional check sum to prevent deserialization of corrupt data.

  - Compatible with Clang, GCC, and MSVC



The underlying reflection mechanism can be used in [other ways](https://cista.rocks/#reflection), too!



**Examples:**



Download the [latest release](https://github.com/felixguendling/cista/releases/latest/download/cista.h) and try it out.



Simple example writing to a buffer:



```cpp

namespace data = cista::raw;

struct my_struct {  // Define your struct.

  int a_{0};

  struct inner {

      data::string b_;

  } j;

};



std::vector buf;

{  // Serialize.

  my_struct obj{1, {data::string{"test"}}};

  buf = cista::serialize(obj);

}



// Deserialize.

auto deserialized = cista::deserialize(buf);

assert(deserialized->j.b_ == data::string{"test"});

```



Advanced example writing a hash map to a memory mapped file:



```cpp

namespace data = cista::offset;

constexpr auto const MODE =  // opt. versioning + check sum

    cista::mode::WITH_VERSION | cista::mode::WITH_INTEGRITY;



struct pos { int x, y; };

using pos_map =  // Automatic deduction of hash & equality

    data::hash_map,

                   data::hash_set>;



{  // Serialize.

  auto positions =

      pos_map{{{{1, 2}, {3, 4}}, {"hello", "cista"}},

              {{{5, 6}, {7, 8}}, {"hello", "world"}}};

  cista::buf mmap{cista::mmap{"data"}};

  cista::serialize(mmap, positions);

}



// Deserialize.

auto b = cista::mmap("data", cista::mmap::protection::READ);

auto positions = cista::deserialize(b);

```



Advanced example showing support for non-aggregate types like derived classes or classes with custom constructors:



```cpp

namespace data = cista::offset;

constexpr auto MODE = cista::mode::WITH_VERSION;



struct parent {

  parent() = default;

  explicit parent(int a) : x_{a}, y_{a} {}

  auto cista_members() { return std::tie(x_, y_); }

  int x_, y_;

};

struct child : parent {

  child() = default;

  explicit child(int a) : parent{a}, z_{a} {}

  auto cista_members() {

    return std::tie(*static_cast(this), z_);

  }

  int z_;

};



/*

 * Automatically defaulted for you:

 *   - de/serialization

 *   - hashing (use child in hash containers)

 *   - equality comparison

 *   - data structure version ("type hash")

 */

using t = data::hash_map;



// ... usage, serialization as in the previous examples

```



# Benchmarks



Have a look at the [benchmark repository](https://github.com/felixguendling/cpp-serialization-benchmark) for more details.



| Library                                               | Serialize      | Deserialize     | Fast Deserialize |   Traverse | Deserialize & Traverse |      Size  |

| :---                                                  |           ---: |            ---: |             ---: |       ---: |                   ---: |       ---: |

| [Cap’n Proto](https://capnproto.org/capnp-tool.html)  |       105 ms   |    **0.002 ms** |       **0.0 ms** |   356 ms   |               353 ms   |    50.5M   |

| [cereal](https://uscilab.github.io/cereal/index.html) |       239 ms   |    197.000 ms   |                - |   125 ms   |               322 ms   |    37.8M   |

| [Cista++](https://cista.rocks/) `offset`              |      **72 ms** |      0.053 ms   |       **0.0 ms** |   132 ms   |             **132 ms** |  **25.3M** |

| [Cista++](https://cista.rocks/) `raw`                 |      3555 ms   |     68.900 ms   |        21.5 ms   | **112 ms** |             **133 ms** |   176.4M   |

| [Flatbuffers](https://google.github.io/flatbuffers/)  |      2349 ms   |     15.400 ms   |       **0.0 ms** |   136 ms   |             **133 ms** |    63.0M   |



# Use Cases



Reader and writer should have the same pointer width. Loading data on systems with a different byte order (endianess) is supported.

Examples:



  - Asset loading for all kinds of applications (i.e. game assets, GIS data, large graphs, etc.)

  - Transferring data over network

  - shared memory applications



Currently, only C++17 software can read/write data.

But it should be possible to generate accessors

for other programming languages, too.



# Alternatives



If you need to be compatible with other programming languages

or require protocol evolution (downward compatibility)

you should look for another solution:



  - [Protocol Buffers](https://developers.google.com/protocol-buffers/)

  - [Cap’n Proto](https://capnproto.org/)

  - [Flatbuffers](https://google.github.io/flatbuffers/)

  - [cereal](https://uscilab.github.io/cereal/)

  - [Boost Serialization](https://www.boost.org/doc/libs/1_68_0/libs/serialization/doc/index.html)

  - [MessagePack](https://msgpack.org/)

  - [tser](https://github.com/KonanM/tser)

  - [... many more](https://en.wikipedia.org/wiki/Comparison_of_data_serialization_formats)



# Documentation



* [Installation and Usage](https://github.com/felixguendling/cista/wiki/Installation-and-Usage)

* [Serialization Reference](https://github.com/felixguendling/cista/wiki/Serialization-Reference)

* [Custom (De-)Serialization Functions](https://github.com/felixguendling/cista/wiki/Custom-(De-)Serialization-Functions)

* [Data Structure Versioning](https://github.com/felixguendling/cista/wiki/Data-Structure-Versioning)

* [Hash Containers](https://github.com/felixguendling/cista/wiki/Hash-Containers)

  * [Hashing Framework](https://github.com/felixguendling/cista/wiki/Hashing-Framework)

  * [Equality Framework](https://github.com/felixguendling/cista/wiki/Equality-Framework)

  * [Benchmark](https://github.com/felixguendling/cista/wiki/Hash-Map-Benchmark)

* [Security](https://github.com/felixguendling/cista/wiki/Security)



# Contribute



Feel free to contribute (bug reports, pull requests, etc.)!