multihash implementation in c++.

Multihash is delivered as

1. A library: libmultihash
2. An executable: bin/multihash

The supplied dockerfile produces a reproducable build image which can be used to compile the source:

docker build -t lockblox/multihash multihash
docker run -it --rm -v multihash:/root/src lockblox/multihash 

Multihash requires some dependencies to be met before building, which are provided via vcpkg as follows:

 git clone https://github.com/lockblox/vcpkg.git \
 cd vcpkg \
 ./bootstrap-vcpkg.sh \
 ./vcpkg integrate install \
 ./vcpkg install gtest cryptopp ms-gsl varint

Multihash uses cmake for builds. In order for cmake to find the required dependencies, the -DCMAKE_TOOLCHAIN_FILE option should be supplied, for example:

 cmake -DCMAKE_TOOLCHAIN_FILE=../vcpkg/scripts/buildsystems/vcpkg.cmake" ../multihash
 cmake --build .

At the lowest level, there is the abstract type multihash::algorithm.

A multihash::algorithm defines the steps required to compute a hash from input data.

multihash::algorithm instances are created by a factory and each factory is registered under a unique hash code identifier.

auto code = multihash::code::sha3_256;
auto algorithm = multihash::algorithm::create(code);
auto buffer = std::string{"hello, world"};
algorithm->update(buffer);
auto result = std::string(256, '=');
algorithm->digest(result);

A multihash::function is a hash functor which operates on iterator pairs.

auto multihash = multihash::function(code)(input.begin(), input.end());

A multihash::multihash combines the hash code and multihash in a binary payload.

auto code = multihash.code();
auto multihash = multihash.multihash();

multihash is released under the MIT License.