codec/include/nil/crypto3/detail/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
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// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.
//---------------------------------------------------------------------------//
 
#ifndef CRYPTO3_DIGEST_HPP
#define CRYPTO3_DIGEST_HPP
 
#include <iostream>
 
#include <boost/static_assert.hpp>
#include <boost/assert.hpp>
 
#include <boost/container/small_vector.hpp>
 
#include <nil/crypto3/detail/pack.hpp>
#include <nil/crypto3/detail/octet.hpp>
 
namespace nil {
    namespace crypto3 {
        template<std::size_t DigestBits>
        using digest = boost::container::small_vector<octet_type, DigestBits / octet_bits>;
 
        namespace detail {
            template<std::size_t DigestBits, typename OutputIterator>
            OutputIterator to_ascii(const boost::container::small_vector<octet_type, DigestBits / octet_bits> &d,
                                    OutputIterator it) {
                for (std::size_t j = 0; j < d.size(); ++j) {
                    octet_type b = d[j];
                    *it++ = "0123456789abcdef"[(b >> 4) & 0xF];
                    *it++ = "0123456789abcdef"[(b >> 0) & 0xF];
                }
                return it;
            }
 
            template<std::size_t DigestBits>
            digest<DigestBits / 4 + 1>
                c_str(const boost::container::small_vector<octet_type, DigestBits / octet_bits> &d) {
                digest<DigestBits / 4 + 1> s;
                to_ascii<DigestBits>(d, std::back_inserter(s));
                s.push_back('\0');
                return s;
            }
        }    // namespace detail
 
 
        template<unsigned NewBits, unsigned OldBits>
        digest<NewBits> reserve(const boost::container::small_vector<octet_type, OldBits / octet_bits> &od) {
            digest<NewBits> nd;
            unsigned bytes = sizeof(octet_type) * (NewBits < OldBits ? NewBits : OldBits) / octet_bits;
            std::memcpy(nd.data(), od.data(), bytes);
            return nd;
        }
 
        template<std::size_t DigestBits>
        digest<DigestBits> resize(const digest<DigestBits> &od, std::size_t new_size) {
            
            std::size_t old_size = od.size();
 
            if (new_size == old_size)
                return od;
 
            digest<DigestBits> nd(new_size, octet_type());
            std::size_t bytes = sizeof(octet_type) * (old_size < new_size ? old_size : new_size);
            std::memcpy(nd.data(), od.data(), bytes);
            return nd;
        }
 
        template<unsigned NewBits, unsigned OldBits>
        digest<NewBits> truncate(const boost::container::small_vector<octet_type, OldBits / octet_bits> &od) {
            BOOST_STATIC_ASSERT(NewBits <= OldBits);
            return resize<NewBits>(od);
        }
 
        template<unsigned DB1, unsigned DB2>
        bool operator==(const digest<DB1> &a, const digest<DB2> &b) {
            unsigned const DB = DB1 < DB2 ? DB2 : DB1;
            return resize<DB>(a).base_array() == resize<DB>(b).base_array();
        }
 
        template<unsigned DB1, unsigned DB2>
        bool operator!=(const digest<DB1> &a, const digest<DB2> &b) {
            return !(a == b);
        }
 
        template<unsigned DB1, unsigned DB2>
        bool operator<(const digest<DB1> &a, const digest<DB2> &b) {
            unsigned const DB = DB1 < DB2 ? DB2 : DB1;
            return resize<DB>(a).base_array() < resize<DB>(b).base_array();
        }
 
        template<unsigned DB1, unsigned DB2>
        bool operator>(const digest<DB1> &a, const digest<DB2> &b) {
            return b < a;
        }
 
        template<unsigned DB1, unsigned DB2>
        bool operator<=(const digest<DB1> &a, const digest<DB2> &b) {
            return !(b < a);
        }
 
        template<unsigned DB1, unsigned DB2>
        bool operator>=(const digest<DB1> &a, const digest<DB2> &b) {
            return !(b > a);
        }
 
        template<unsigned DB>
        bool operator!=(digest<DB> const &a, char const *b) {
            BOOST_ASSERT(std::strlen(b) == DB / 4);
            return static_cast<bool>(std::strcmp(a.cstring().data(), b));
        }
 
        template<unsigned DB>
        bool operator==(digest<DB> const &a, char const *b) {
            return !(a != b);
        }
 
        template<unsigned DB>
        bool operator!=(char const *b, digest<DB> const &a) {
            return a != b;
        }
 
        template<unsigned DB>
        bool operator==(char const *b, digest<DB> const &a) {
            return a == b;
        }
 
        template<unsigned DB>
        std::ostream &operator<<(std::ostream &sink, digest<DB> const &d) {
            d.to_ascii(std::ostream_iterator<char>(sink));
            return sink;
        }
 
        template<unsigned DB>
        std::istream &operator>>(std::istream &source, digest<DB> &d) {
            std::array<char, DB / 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
 
namespace std {
    template<std::size_t DigestBits>
    std::string to_string(const nil::crypto3::digest<DigestBits> &d) {
        nil::crypto3::digest<DigestBits / 4 + 1> cstr = nil::crypto3::detail::c_str(d);
        return std::string(cstr.begin(), cstr.begin() + cstr.size() - 1);
    }
}    // namespace std
 
#endif    // CRYPTO3_DIGEST_HPP