hash.hpp

/*
  ANCH Framework: ANother C++ Hack is a C++ framework based on C++11 standard
  Copyright (C) 2012 Vincent Lachenal

  This file is part of ANCH Framework.

  ANCH Framework is free software: you can redistribute it and/or modify
  it under the terms of the GNU Lesser General Public License as published by
  the Free Software Foundation, either version 3 of the License, or
  (at your option) any later version.

  ANCH Framework is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU Lesser General Public License for more details.

  You should have received a copy of the GNU Lesser General Public License
  along with ANCH Framework.  If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef _ANCH_CRYPTO_HASH_H_
#define _ANCH_CRYPTO_HASH_H_

#include <iostream>
#include <ostream>
#include <iomanip>
#include <array>


namespace anch {
  namespace crypto {

    template<std::size_t O, std::size_t B>
    class Hash {

      // Methods +
    public:
      virtual const std::array<uint8_t,O>& digest() const = 0;

      template<class CharT, class Traits, class Allocator>
      const std::array<uint8_t,O>& digest(const std::basic_string<CharT,Traits,Allocator>& data) {
        reset();
        addData(reinterpret_cast<const uint8_t*>(data.data()), data.length());
        finalize();
        return digest();
      }

      template<std::size_t N>
      const std::array<uint8_t,O>& digest(const std::array<uint8_t,N>& data) {
        reset();
        addData(data.data(), N);
        finalize();
        return digest();
      }

      const std::array<uint8_t,O>& digest(const uint8_t* data, std::size_t len) {
        reset();
        addData(data, len);
        finalize();
        return digest();
      }

      template<class CharT, class Traits>
      const std::array<uint8_t,O>& digest(std::basic_istream<CharT,Traits>& stream) {
        reset();
        if(stream) {
          char data[1024];
          while(!stream.eof()) {
            stream.read(data, 1024);
            addData(reinterpret_cast<uint8_t*>(data), stream.gcount());
          }
          finalize();
        }
        return digest();
      }

    protected:
      virtual void reset() = 0;

      virtual void addData(const uint8_t* data, std::size_t len) = 0;

      virtual void finalize() = 0;
      // Methods -


      // Accessors +
    public:
      inline static constexpr std::size_t getOutputSize() {
        return O;
      }

      inline static constexpr std::size_t getBlockSize() {
        return B;
      }
      // Accessors -

    };

  }
}

template<class CharT, class Traits, std::size_t O, std::size_t B>
std::basic_ostream<CharT, Traits>&
operator << (std::basic_ostream<CharT, Traits>& out, const anch::crypto::Hash<O,B>& hash) {
  std::ios_base::fmtflags flags = out.flags(); // Save current flags
  out << std::hex;
  for(const uint8_t& byte : hash.digest()) {
    out << std::setfill('0') << std::setw(2) << static_cast<uint16_t>(byte);
  }
  out.flags(flags); // Restore flags
  return out;
}

#endif // _ANCH_CRYPTO_HASH_H_