catch2/internal/catch_sharding.hpp

0001
0002 //              Copyright Catch2 Authors
0003 // Distributed under the Boost Software License, Version 1.0.
0004 //   (See accompanying file LICENSE.txt or copy at
0005 //        https://www.boost.org/LICENSE_1_0.txt)
0006
0007 // SPDX-License-Identifier: BSL-1.0
0008 #ifndef CATCH_SHARDING_HPP_INCLUDED
0009 #define CATCH_SHARDING_HPP_INCLUDED
0010
0011 #include <catch2/catch_session.hpp>
0012
0013 #include <cmath>
0014 #include <algorithm>
0015
0016 namespace Catch {
0017
0018     template<typename Container>
0019     Container createShard(Container const& container, std::size_t const shardCount, std::size_t const shardIndex) {
0020         assert(shardCount > shardIndex);
0021
0022         if (shardCount == 1) {
0023             return container;
0024         }
0025
0026         const std::size_t totalTestCount = container.size();
0027
0028         const std::size_t shardSize = totalTestCount / shardCount;
0029         const std::size_t leftoverTests = totalTestCount % shardCount;
0030
0031         const std::size_t startIndex = shardIndex * shardSize + (std::min)(shardIndex, leftoverTests);
0032         const std::size_t endIndex = (shardIndex + 1) * shardSize + (std::min)(shardIndex + 1, leftoverTests);
0033
0034         auto startIterator = std::next(container.begin(), static_cast<std::ptrdiff_t>(startIndex));
0035         auto endIterator = std::next(container.begin(), static_cast<std::ptrdiff_t>(endIndex));
0036
0037         return Container(startIterator, endIterator);
0038     }
0039
0040 }
0041
0042 #endif // CATCH_SHARDING_HPP_INCLUDED