ccrc (C++ CRC)

A simple header only CRC class.

Motivation

A simple CRC class without external dependancies, I also wanted to make use of constexpr to calculate LUTs at compile time.

Prerequisites

• cmake
• Catch2 - for unit testing

Build

mkdir build && cd build
cmake -DBUILD_TEST=ON -DBUILD_EXAMPLE=ON ..
make -j

Unit tests

Unit tests are built on Catch2.

To run tests simply run:

./run_all_tests.sh

Example

The project provides an example application. Currently the application supports the following operations:

./bin/ccrc_example -h                                                                     ✹
Example crc usage.
Usage:
  crc_example [OPTION...]

      --help       Print help
  -f, --file arg   File input.
  -i, --input arg  String input

Example input string:

./bin/ccrc_example -i "123456789"                                                         ✹
[2019-08-09 23:59:35.762] [crc] [info] Attempting to checksum string : '123456789'
[2019-08-09 23:59:35.762] [crc] [info]  crc32_default_t : 0xcbf43926
[2019-08-09 23:59:35.762] [crc] [info]          bzip2_t : 0xfc891918
[2019-08-09 23:59:35.762] [crc] [info]         crc32c_t : 0xe3069283
[2019-08-09 23:59:35.762] [crc] [info]         crc32d_t : 0x87315576
[2019-08-09 23:59:35.762] [crc] [info]          mpeg2_t : 0x376e6e7
[2019-08-09 23:59:35.762] [crc] [info]          posix_t : 0x765e7680
### More results here
[2019-08-09 23:59:35.762] [crc] [info]         i_code_t : 0x7e
[2019-08-09 23:59:35.762] [crc] [info]            itu_t : 0xa1
[2019-08-09 23:59:35.762] [crc] [info]         maxim8_t : 0xa1
[2019-08-09 23:59:35.762] [crc] [info]           rohc_t : 0xd0
[2019-08-09 23:59:35.762] [crc] [info]          wcdma_t : 0x25

You can compare these values to an online calculator such as crccalc

You can also checksum files:

./bin/ccrc_example -f ../LICENSE.md                                                       ✹
[2019-08-10 00:00:48.094] [crc] [info] Attempting to checksum file : '../LICENSE.md'
[2019-08-10 00:00:48.094] [crc] [info] 1075 bytes read
[2019-08-10 00:00:48.094] [crc] [info]  crc32_default_t : 0x29d01e9d
[2019-08-10 00:00:48.094] [crc] [info]          bzip2_t : 0x9c17fcb9
[2019-08-10 00:00:48.094] [crc] [info]         crc32c_t : 0x101f9585
[2019-08-10 00:00:48.094] [crc] [info]         crc32d_t : 0x1f31440
[2019-08-10 00:00:48.095] [crc] [info]          mpeg2_t : 0x63e80346
[2019-08-10 00:00:48.095] [crc] [info]          posix_t : 0x267b554
### More results here
[2019-08-10 00:00:48.100] [crc] [info]         i_code_t : 0x81
[2019-08-10 00:00:48.100] [crc] [info]            itu_t : 0xfe
[2019-08-10 00:00:48.100] [crc] [info]         maxim8_t : 0xfb
[2019-08-10 00:00:48.100] [crc] [info]           rohc_t : 0xc8
[2019-08-10 00:00:48.101] [crc] [info]          wcdma_t : 0x4f

Versioning

We use SemVer for versioning. For the versions available, see the tags on this repository.

Usage

#include "crc/crc.h"

//  using namespace ccrc::base; // Classic byte wise CRC, good if you cannot afford memory req.
using namespace ccrc::fast; //Table based, size depends on the checksum used.

int main(int argc, char **argv) {
    constexpr static std::array<uint8_t, 4> t_small = {{0xDE, 0xAD, 0xBE, 0xEF}};
    std::cout << crc32_default_t::checksum(t_small) << std::endl;
}

License

This project is licensed under the MIT License - see the LICENSE.md file for details

Acknowledgments

• sunshine2k - Online CRC calculator used to confirm checksums with all the neccearry pre-defined checksums.
• jarro2783 - cxxopts - awesome command line parser in C++.
• Boost crc - great library which has inspired this project.

See also the list of contributors who participated in this project.