block/include/nil/crypto3/detail/static_digest.hpp

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//---------------------------------------------------------------------------//
// Copyright (c) 2018-2020 Mikhail Komarov <nemo@nil.foundation>
//
// MIT License
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.
//---------------------------------------------------------------------------//
 
#ifndef CRYPTO3_STATIC_DIGEST_HPP
#define CRYPTO3_STATIC_DIGEST_HPP
 
#include <boost/static_assert.hpp>
#include <boost/assert.hpp>
 
#include <array>
#include <string>
#include <cstring>
#include <iostream>
 
#include <nil/crypto3/detail/octet.hpp>
#include <nil/crypto3/detail/pack.hpp>
 
namespace nil {
    namespace crypto3 {
        template<std::size_t DigestBits>
        class static_digest : public std::array<octet_type, DigestBits / octet_bits> { };
 
        namespace detail {
            template<std::size_t DigestBits, typename OutputIterator>
            OutputIterator to_ascii(const static_digest<DigestBits> &d, OutputIterator it) {
                for (std::size_t j = 0; j < DigestBits / octet_bits; ++j) {
                    octet_type b = d[j];
                    *it++ = "0123456789abcdef"[(b >> 4) & 0xF];
                    *it++ = "0123456789abcdef"[(b >> 0) & 0xF];
                }
                return it;
            }
 
            template<std::size_t DigestBits>
            std::array<char, DigestBits / 4 + 1> c_str(const static_digest<DigestBits> &d) {
                std::array<char, DigestBits / 4 + 1> s;
                char *p = to_ascii<DigestBits>(d, s.data());
                *p++ = '\0';
                return s;
            }
        }    // namespace detail
    }        // namespace crypto3
}    // namespace nil
 
namespace std {
    template<std::size_t DigestBits>
    std::string to_string(const nil::crypto3::static_digest<DigestBits> &d) {
        std::array<char, DigestBits / 4 + 1> cstr = nil::crypto3::detail::c_str(d);
        return std::string(cstr.data(), cstr.size() - 1);
    }
}    // namespace std
 
namespace nil {
    namespace crypto3 {
 
        template<std::size_t NewBits, std::size_t OldBits>
        static_digest<NewBits> resize(const static_digest<OldBits> &od) {
            static_digest<NewBits> nd;
            nd.fill(0);
            std::size_t bytes = sizeof(octet_type) * (NewBits < OldBits ? NewBits : OldBits) / octet_bits;
            std::memcpy(nd.data(), od.data(), bytes);
            return nd;
        }
 
        template<std::size_t NewBits, std::size_t OldBits>
        static_digest<NewBits> truncate(const static_digest<OldBits> &od) {
            BOOST_STATIC_ASSERT(NewBits <= OldBits);
            return resize<NewBits>(od);
        }
 
        template<std::size_t DB1, std::size_t DB2>
        bool operator==(const static_digest<DB1> &a, const static_digest<DB2> &b) {
            // TODO: Think about size of static_digest. We can't use resize here because
            //  it's change element which we compare
            return static_cast<bool>(DB1 == DB2 ? std::equal(std::begin(a), std::end(a), std::begin(b), std::end(b)) :
                                                  0);
        }
 
        template<std::size_t DB1, std::size_t DB2>
        bool operator!=(const static_digest<DB1> &a, const static_digest<DB2> &b) {
            return !(a == b);
        }
 
        template<std::size_t DB1, std::size_t DB2>
        bool operator<(const static_digest<DB1> &a, const static_digest<DB2> &b) {
            // #TODO: Implement this right
            return DB1 < DB2;
        }
 
        template<std::size_t DB1, std::size_t DB2>
        bool operator>(const static_digest<DB1> &a, const static_digest<DB2> &b) {
            return b < a;
        }
 
        template<std::size_t DB1, std::size_t DB2>
        bool operator<=(const static_digest<DB1> &a, const static_digest<DB2> &b) {
            return !(b < a);
        }
 
        template<std::size_t DB1, std::size_t DB2>
        bool operator>=(const static_digest<DB1> &a, const static_digest<DB2> &b) {
            return !(b > a);
        }
 
        template<std::size_t DB>
        bool operator!=(const static_digest<DB> &a, char const *b) {
            BOOST_ASSERT(std::strlen(b) == DB / 4);
            return std::to_string(a) != b;
        }
 
        template<std::size_t DB>
        bool operator==(const static_digest<DB> &a, char const *b) {
            return !(a != b);
        }
 
        template<std::size_t DB>
        bool operator!=(char const *b, const static_digest<DB> &a) {
            return a != b;
        }
 
        template<std::size_t DB>
        bool operator==(char const *b, const static_digest<DB> &a) {
            return a == b;
        }
 
        template<std::size_t DigestBits>
        std::ostream &operator<<(std::ostream &sink, const static_digest<DigestBits> &d) {
            detail::to_ascii<DigestBits>(d, std::ostream_iterator<char>(sink));
            return sink;
        }
 
        template<std::size_t DigestBits>
        std::istream &operator>>(std::istream &source, static_digest<DigestBits> &d) {
            std::array<char, DigestBits / 4> a = {{}};
            for (unsigned i = 0; i < a.size(); ++i) {
                char c;
                if (!source.get(c)) {
                    source.setstate(std::ios::failbit);
                    break;
                }
                if (!std::isxdigit(c, source.getloc())) {
                    source.unget();
                    source.setstate(std::ios::failbit);
                    break;
                }
 
                if (std::isdigit(c, source.getloc())) {
                    a[i] = (c - '0');
                } else {
                    a[i] = std::toupper(c, source.getloc()) - 'A' + 0xA;
                }
            }
            detail::pack<stream_endian::big_bit, stream_endian::big_bit, 4, 8>(a.begin(), a.end(), d.begin());
            return source;
        }
    }    // namespace crypto3
}    // namespace nil
 
#endif    // CRYPTO3_HASH_DIGEST_HPP