// Copyright 2016 Proyectos y Sistemas de Mantenimiento SL (eProsima).

//

// 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.

/**

 * @file SequenceNumber.hpp

 */

#ifndef FASTDDS_RTPS_COMMON__SEQUENCENUMBER_HPP

#define FASTDDS_RTPS_COMMON__SEQUENCENUMBER_HPP

#include <algorithm>

#include <cassert>

#include <limits>

#include <vector>

#include <fastdds/fastdds_dll.hpp>

#include <fastdds/rtps/common/Types.hpp>

#include <fastdds/utils/fixed_size_bitmap.hpp>

namespace eprosima {

namespace fastdds {

namespace rtps {

//!@brief Structure SequenceNumber_t, different for each change in the same writer.

//!@ingroup COMMON_MODULE

struct FASTDDS_EXPORTED_API SequenceNumber_t

{

    //!

    int32_t high = 0;

    //!

    uint32_t low = 0;

    //! Default constructor

    SequenceNumber_t() noexcept

    {

        high = 0;

        low = 0;

    }

    /*!

     * @param hi

     * @param lo

     */

    SequenceNumber_t(

            int32_t hi,

            uint32_t lo) noexcept

        : high(hi)

        , low(lo)

    {

    }

    /*!

     * @param u

     */

    explicit SequenceNumber_t(

            uint64_t u) noexcept

        : high(static_cast<int32_t>(u >> 32u))

        , low(static_cast<uint32_t>(u))

    {

    }

    /*! Convert the number to 64 bit.

     * @return 64 bit representation of the SequenceNumber

     */

    uint64_t to64long() const noexcept

    {

        return (static_cast<uint64_t>(high) << 32u) + low;

    }

    //! Increase SequenceNumber in 1.

    SequenceNumber_t& operator ++() noexcept

    {

        ++low;

        if (low == 0)

        {

            assert(std::numeric_limits<decltype(high)>::max() > high);

            ++high;

        }

        return *this;

    }

    SequenceNumber_t operator ++(

            int) noexcept

    {

        SequenceNumber_t result(*this);

        ++(*this);

        return result;

    }

    /**

     * Increase SequenceNumber.

     * @param inc Number to add to the SequenceNumber

     */

    SequenceNumber_t& operator +=(

            int inc) noexcept

    {

        assert(inc >= 0);

        uint32_t aux_low = low;

        low += static_cast<uint32_t>(inc);

        if (low < aux_low)

        {

            // Being the type of the parameter an 'int', the increment of 'high' will be as much as 1.

            assert(std::numeric_limits<decltype(high)>::max() > high);

            ++high;

        }

        return *this;

    }

    static SequenceNumber_t unknown() noexcept

    {

        return {-1, 0};

    }

};

#ifndef DOXYGEN_SHOULD_SKIP_THIS_PUBLIC

/**

 * Compares two SequenceNumber_t.

 * @param sn1 First SequenceNumber_t to compare

 * @param sn2 Second SequenceNumber_t to compare

 * @return True if equal

 */

inline bool operator ==(

        const SequenceNumber_t& sn1,

        const SequenceNumber_t& sn2) noexcept

{

    return (sn1.low == sn2.low) && (sn1.high == sn2.high);

}

/**

 * Compares two SequenceNumber_t.

 * @param sn1 First SequenceNumber_t to compare

 * @param sn2 Second SequenceNumber_t to compare

 * @return True if not equal

 */

inline bool operator !=(

        const SequenceNumber_t& sn1,

        const SequenceNumber_t& sn2) noexcept

{

    return (sn1.low != sn2.low) || (sn1.high != sn2.high);

}

/**

 * Checks if a SequenceNumber_t is greater than other.

 * @param seq1 First SequenceNumber_t to compare

 * @param seq2 Second SequenceNumber_t to compare

 * @return True if the first SequenceNumber_t is greater than the second

 */

inline bool operator >(

        const SequenceNumber_t& seq1,

        const SequenceNumber_t& seq2) noexcept

{

    if (seq1.high == seq2.high)

    {

        return seq1.low > seq2.low;

    }

    return seq1.high > seq2.high;

}

/**

 * Checks if a SequenceNumber_t is less than other.

 * @param seq1 First SequenceNumber_t to compare

 * @param seq2 Second SequenceNumber_t to compare

 * @return True if the first SequenceNumber_t is less than the second

 */

inline bool operator <(

        const SequenceNumber_t& seq1,

        const SequenceNumber_t& seq2) noexcept

{

    if (seq1.high == seq2.high)

    {

        return seq1.low < seq2.low;

    }

    return seq1.high < seq2.high;

}

/**

 * Checks if a SequenceNumber_t is greater or equal than other.

 * @param seq1 First SequenceNumber_t to compare

 * @param seq2 Second SequenceNumber_t to compare

 * @return True if the first SequenceNumber_t is greater or equal than the second

 */

inline bool operator >=(

        const SequenceNumber_t& seq1,

        const SequenceNumber_t& seq2) noexcept

{

    if (seq1.high == seq2.high)

    {

        return seq1.low >= seq2.low;

    }

    return seq1.high > seq2.high;

}

/**

 * Checks if a SequenceNumber_t is less or equal than other.

 * @param seq1 First SequenceNumber_t to compare

 * @param seq2 Second SequenceNumber_t to compare

 * @return True if the first SequenceNumber_t is less or equal than the second

 */

inline bool operator <=(

        const SequenceNumber_t& seq1,

        const SequenceNumber_t& seq2) noexcept

{

    if (seq1.high == seq2.high)

    {

        return seq1.low <= seq2.low;

    }

    return seq1.high < seq2.high;

}

/**

 * Subtract one uint32_t from a SequenceNumber_t

 * @param seq Base SequenceNumber_t

 * @param inc uint32_t to subtract

 * @return Result of the subtraction

 */

inline SequenceNumber_t operator -(

        const SequenceNumber_t& seq,

        const uint32_t inc) noexcept

{

    SequenceNumber_t res(seq.high, seq.low - inc);

    if (inc > seq.low)

    {

        // Being the type of the parameter an 'uint32_t', the decrement of 'high' will be as much as 1.

        assert(0 < res.high);

        --res.high;

    }

    return res;

}

/**

 * Add one uint32_t to a SequenceNumber_t

 * @param [in] seq Base sequence number

 * @param inc value to add to the base

 * @return Result of the addition

 */

inline SequenceNumber_t operator +(

        const SequenceNumber_t& seq,

        const uint32_t inc) noexcept

{

    SequenceNumber_t res(seq.high, seq.low + inc);

    if (res.low < seq.low)

    {

        // Being the type of the parameter an 'uint32_t', the increment of 'high' will be as much as 1.

        assert(std::numeric_limits<decltype(res.high)>::max() > res.high);

        ++res.high;

    }

    return res;

}

/**

 * Subtract one SequenceNumber_t to another

 * @param minuend Minuend. Has to be greater than or equal to subtrahend.

 * @param subtrahend Subtrahend.

 * @return Result of the subtraction

 */

inline SequenceNumber_t operator -(

        const SequenceNumber_t& minuend,

        const SequenceNumber_t& subtrahend) noexcept

{

    assert(minuend >= subtrahend);

    SequenceNumber_t res(minuend.high - subtrahend.high, minuend.low - subtrahend.low);

    if (minuend.low < subtrahend.low)

    {

        assert(0 < res.high);

        --res.high;

    }

    return res;

}

#endif // ifndef DOXYGEN_SHOULD_SKIP_THIS_PUBLIC

const SequenceNumber_t c_SequenceNumber_Unknown{-1, 0};

#ifndef DOXYGEN_SHOULD_SKIP_THIS_PUBLIC

/**

 * Sorts two instances of SequenceNumber_t

 * @param s1 First SequenceNumber_t to compare

 * @param s2 First SequenceNumber_t to compare

 * @return True if s1 is less than s2

 */

inline bool sort_seqNum(

        const SequenceNumber_t& s1,

        const SequenceNumber_t& s2) noexcept

{

    return s1 < s2;

}

/**

 *

 * @param output

 * @param seqNum

 * @return

 */

inline std::ostream& operator <<(

        std::ostream& output,

        const SequenceNumber_t& seqNum)

{

    return output << seqNum.to64long();

}

inline std::ostream& operator <<(

        std::ostream& output,

        const std::vector<SequenceNumber_t>& seqNumSet)

{

    for (const SequenceNumber_t& sn : seqNumSet)

    {

        output << sn << " ";

    }

    return output;

}

/*!

 * @brief Defines the STL hash function for type SequenceNumber_t.

 */

struct SequenceNumberHash

{

    std::size_t operator ()(

            const SequenceNumber_t& sequence_number) const noexcept

    {

        return static_cast<std::size_t>(sequence_number.to64long());

    }

};

struct SequenceNumberDiff

{

    uint32_t operator ()(

            const SequenceNumber_t& a,

            const SequenceNumber_t& b) const noexcept

    {

        SequenceNumber_t diff = a - b;

        return diff.low;

    }

};

#endif // ifndef DOXYGEN_SHOULD_SKIP_THIS_PUBLIC

//! Structure SequenceNumberSet_t, contains a group of sequencenumbers.

using SequenceNumberSet_t = BitmapRange<SequenceNumber_t, SequenceNumberDiff, 256>;

#ifndef DOXYGEN_SHOULD_SKIP_THIS_PUBLIC

/**

 * Prints a sequence Number set

 * @param output Output Stream

 * @param sns SequenceNumber set

 * @return OStream.

 */

inline std::ostream& operator <<(

        std::ostream& output,

        const SequenceNumberSet_t& sns)

{

    output << sns.base().to64long() << ":";

    sns.for_each([&output](

                SequenceNumber_t it)

            {

                output << it.to64long() << "-";

            });

    return output;

}

/**

 *

 * @param input

 * @param seqNum

 * @return

 */

inline std::istream& operator >>(

        std::istream& input,

        SequenceNumber_t& seqNum)

{

    uint64_t aux;

    if (input >> aux)

    {

        seqNum = SequenceNumber_t(aux);

    }

    return input;

}

#endif // DOXYGEN_SHOULD_SKIP_THIS_PUBLIC

} // namespace rtps

} // namespace fastdds

} // namespace eprosima

#endif // FASTDDS_RTPS_COMMON__SEQUENCENUMBER_HPP