checksum.cpp

/*
Copyright [2024] [Yao Yao]

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.

*/

#include "checksum.h"
#include <boost/uuid/detail/md5.hpp>
#include <boost/uuid/detail/sha1.hpp>
#include <fstream>
#include <filesystem>

namespace {
// for C++20 std::to_array
template <typename T, size_t size>
constexpr std::array<T, size> toArray(const T(&src)[size]) {
    std::array<T, size> dst{};
    std::copy_n(src, size, dst.begin());
    return dst;
}

template <typename Algo>
auto checksum(const void* data, size_t size)
{
    Algo hash{};
    hash.process_bytes(data, size);
    typename Algo::digest_type digest;
    hash.get_digest(digest);
    return toArray(digest);
}

template <typename Algo>
auto checksum(const char* filename)
{
    Algo hash{};
    std::ifstream fin;
    fin.exceptions(std::ios::badbit);
    fin.open(filename, std::ios::binary);
    std::vector<char> buffer(256<<10);
    while (fin.good()) {
        const auto nbBytes = fin.read(buffer.data(), buffer.size()).gcount();
        hash.process_bytes(buffer.data(), nbBytes);
    }
    typename Algo::digest_type digest;
    hash.get_digest(digest);
    return toArray(digest);
}
}

namespace cudapp {

std::array<uint32_t, 4> md5sum(const void* data, size_t size)
{
    return checksum<boost::uuids::detail::md5>(data, size);
}

std::array<uint32_t, 4> md5sum(const char* filename)
{
    return checksum<boost::uuids::detail::md5>(filename);
}

std::array<uint32_t, 5> sha1sum(const void* data, size_t size)
{
    return checksum<boost::uuids::detail::sha1>(data, size);
}
std::array<uint32_t, 5> sha1sum(const char* filename)
{
    return checksum<boost::uuids::detail::sha1>(filename);
}

} // namespace cudapp