///\file

/******************************************************************************
The MIT License(MIT)

Embedded Template Library.

Copyright(c) 2014 jwellbelove

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
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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,
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SOFTWARE.
******************************************************************************/

#ifndef __ETL_CRC64_ECMA__
#define __ETL_CRC64_ECMA__

#include <cstdint>

///\defgroup crc64_ecma Sixty four bit CRC ECMA calculation
///\ingroup crc

namespace etl
{
  //***************************************************************************
  /// CRC64_ECMA table
  /// \ingroup crc64_ecma
  //***************************************************************************
  extern const uint64_t CRC64_ECMA[];

  //***************************************************************************
  /// Calculates CRC64-ECMA using polynomial 0x42F0E1EBA9EA3693.
  /// \ingroup crc64_ecma
  //***************************************************************************
  class crc64_ecma
  {
  public:

    typedef uint64_t value_type;

    //*************************************************************************
    /// Default constructor.
    //*************************************************************************
    crc64_ecma()
    {
      reset();
    }

    //*************************************************************************
    /// Constructor from range.
    /// \param begin Start of the range.
    /// \param end   End of the range.
    /// \return The CRC result.
    //*************************************************************************
    template<typename TIterator>
    crc64_ecma(TIterator begin, const TIterator end)
    {
      reset();
      add(begin, end);
    }

    //*************************************************************************
    /// Resets the CRC to the initial state.
    //*************************************************************************
    void reset()
    {
      crc = 0;
    }

    //*************************************************************************
    /// \param value The value to add to the CRC.
    /// \return The CRC result.
    //*************************************************************************
    template<typename TValue>
    void add(TValue value)
    {
      // How many steps in a value?
      size_t steps = sizeof(TValue) / sizeof(uint8_t);

      uint8_t* p_data = reinterpret_cast<uint8_t*>(&value);

      for (size_t i = 0; i < steps; ++i)
      {
        crc = (crc << 8) ^ CRC64_ECMA[((crc >> 56) ^ p_data[i]) & 0xFF];
      }
    }

    //*************************************************************************
    /// \param begin Start of the range.
    /// \param end   End of the range.
    /// \return The CRC result.
    //*************************************************************************
    template<typename TIterator>
    void add(TIterator begin, const TIterator end)
    {
      while (begin != end)
      {
        add(*begin);
        ++begin;
      }
    }

    //*************************************************************************
    /// Gets the CRC value.
    //*************************************************************************
    value_type value() const
    {
      return crc;
    }

    //*************************************************************************
    /// Conversion operator to value_type.
    //*************************************************************************
    operator value_type () const
    {
      return crc;
    }

  private:

    value_type crc;
  };
}

#endif