sequence-number.h

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//
// Copyright (c) 2008-2010 INESC Porto
//
// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License version 2 as
// published by the Free Software Foundation;
//
// This program 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 General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
//
// Author: Gustavo J. A. M. Carneiro  <gjc@inescporto.pt> <gjcarneiro@gmail.com>
//
 
#ifndef NS3_SEQ_NUM_H
#define NS3_SEQ_NUM_H
 
#include "ns3/type-name.h"
 
#include <iostream>
#include <limits>
#include <stdint.h>
 
namespace ns3
{
 
template <typename NUMERIC_TYPE, typename SIGNED_TYPE>
class SequenceNumber
{
  public:
    SequenceNumber()
        : m_value(0)
    {
    }
 
    explicit SequenceNumber(NUMERIC_TYPE value)
        : m_value(value)
    {
    }
 
    SequenceNumber(const SequenceNumber<NUMERIC_TYPE, SIGNED_TYPE>& value)
        : m_value(value.m_value)
    {
    }
 
    SequenceNumber<NUMERIC_TYPE, SIGNED_TYPE>& operator=(NUMERIC_TYPE value)
    {
        m_value = value;
        return *this;
    }
 
    SequenceNumber<NUMERIC_TYPE, SIGNED_TYPE>& operator=(
        const SequenceNumber<NUMERIC_TYPE, SIGNED_TYPE>& value)
    {
        m_value = value.m_value;
        return *this;
    }
 
#if 0
  // a SequenceNumber implicitly converts to a plain number, but not the other way around
  operator NUMERIC_TYPE () const
  {
    return m_value;
  }
#endif
 
    NUMERIC_TYPE GetValue() const
    {
        return m_value;
    }
 
    SequenceNumber<NUMERIC_TYPE, SIGNED_TYPE> operator++()
    {
        m_value++;
        return *this;
    }
 
    SequenceNumber<NUMERIC_TYPE, SIGNED_TYPE> operator++(int)
    {
        SequenceNumber<NUMERIC_TYPE, SIGNED_TYPE> retval(m_value);
        m_value++;
        return retval;
    }
 
    SequenceNumber<NUMERIC_TYPE, SIGNED_TYPE> operator--()
    {
        m_value--;
        return *this;
    }
 
    SequenceNumber<NUMERIC_TYPE, SIGNED_TYPE> operator--(int)
    {
        SequenceNumber<NUMERIC_TYPE, SIGNED_TYPE> retval(m_value);
        m_value--;
        return retval;
    }
 
    SequenceNumber<NUMERIC_TYPE, SIGNED_TYPE>& operator+=(SIGNED_TYPE value)
    {
        m_value += value;
        return *this;
    }
 
    SequenceNumber<NUMERIC_TYPE, SIGNED_TYPE>& operator-=(SIGNED_TYPE value)
    {
        m_value -= value;
        return *this;
    }
 
    SequenceNumber<NUMERIC_TYPE, SIGNED_TYPE> operator+(
        const SequenceNumber<NUMERIC_TYPE, SIGNED_TYPE>& other) const
    {
        return SequenceNumber<NUMERIC_TYPE, SIGNED_TYPE>(m_value + other.m_value);
    }
 
    SequenceNumber<NUMERIC_TYPE, SIGNED_TYPE> operator+(SIGNED_TYPE delta) const
    {
        return SequenceNumber<NUMERIC_TYPE, SIGNED_TYPE>(m_value + delta);
    }
 
    SequenceNumber<NUMERIC_TYPE, SIGNED_TYPE> operator-(SIGNED_TYPE delta) const
    {
        return SequenceNumber<NUMERIC_TYPE, SIGNED_TYPE>(m_value - delta);
    }
 
    SIGNED_TYPE operator-(const SequenceNumber<NUMERIC_TYPE, SIGNED_TYPE>& other) const
    {
        static const NUMERIC_TYPE maxValue = std::numeric_limits<NUMERIC_TYPE>::max();
        static const NUMERIC_TYPE halfMaxValue = std::numeric_limits<NUMERIC_TYPE>::max() / 2;
        if (m_value > other.m_value)
        {
            NUMERIC_TYPE diff = m_value - other.m_value;
            if (diff < halfMaxValue)
            {
                return static_cast<SIGNED_TYPE>(diff);
            }
            else
            {
                //      |------------|------------|
                //       ====                  ===
                //          ^                  ^
                //       other.m_value      m_value
                return -(static_cast<SIGNED_TYPE>(maxValue - m_value + 1 + other.m_value));
            }
        }
        else
        {
            NUMERIC_TYPE diff = other.m_value - m_value;
            if (diff < halfMaxValue)
            {
                //      |------------|------------|
                //          ========
                //          ^      ^
                //     m_value   other.m_value
                return -(static_cast<SIGNED_TYPE>(diff));
            }
            else
            {
                //      |------------|------------|
                //       ====                  ===
                //          ^                  ^
                //       m_value      other.m_value
                return static_cast<SIGNED_TYPE>(maxValue - other.m_value + 1 + m_value);
            }
        }
    }
 
    bool operator>(const SequenceNumber<NUMERIC_TYPE, SIGNED_TYPE>& other) const
    {
        static const NUMERIC_TYPE halfMaxValue = std::numeric_limits<NUMERIC_TYPE>::max() / 2;
 
        return (((m_value > other.m_value) && (m_value - other.m_value) <= halfMaxValue) ||
                ((other.m_value > m_value) && (other.m_value - m_value) > halfMaxValue));
    }
 
    bool operator==(const SequenceNumber<NUMERIC_TYPE, SIGNED_TYPE>& other) const
    {
        return (m_value == other.m_value);
    }
 
    bool operator!=(const SequenceNumber<NUMERIC_TYPE, SIGNED_TYPE>& other) const
    {
        return (m_value != other.m_value);
    }
 
    bool operator<=(const SequenceNumber<NUMERIC_TYPE, SIGNED_TYPE>& other) const
    {
        return (!this->operator>(other));
    }
 
    bool operator>=(const SequenceNumber<NUMERIC_TYPE, SIGNED_TYPE>& other) const
    {
        return (this->operator>(other) || this->operator==(other));
    }
 
    bool operator<(const SequenceNumber<NUMERIC_TYPE, SIGNED_TYPE>& other) const
    {
        return !this->operator>(other) && m_value != other.m_value;
    }
 
    template <typename NUMERIC_TYPE2, typename SIGNED_TYPE2>
    friend std::ostream& operator<<(std::ostream& os,
                                    const SequenceNumber<NUMERIC_TYPE2, SIGNED_TYPE2>& val);
 
    template <typename NUMERIC_TYPE2, typename SIGNED_TYPE2>
    friend std::istream& operator>>(std::istream& is,
                                    const SequenceNumber<NUMERIC_TYPE2, SIGNED_TYPE2>& val);
 
  public:
    // Unimplemented operators
    SequenceNumber<NUMERIC_TYPE, SIGNED_TYPE>& operator+=(
        const SequenceNumber<NUMERIC_TYPE, SIGNED_TYPE>&) = delete;
    SequenceNumber<NUMERIC_TYPE, SIGNED_TYPE>& operator-=(
        const SequenceNumber<NUMERIC_TYPE, SIGNED_TYPE>&) = delete;
    SequenceNumber<NUMERIC_TYPE, SIGNED_TYPE> operator*(
        const SequenceNumber<NUMERIC_TYPE, SIGNED_TYPE>&) const = delete;
    SequenceNumber<NUMERIC_TYPE, SIGNED_TYPE> operator/(
        const SequenceNumber<NUMERIC_TYPE, SIGNED_TYPE>&) const = delete;
    SequenceNumber<NUMERIC_TYPE, SIGNED_TYPE> operator%(
        const SequenceNumber<NUMERIC_TYPE, SIGNED_TYPE>&) const = delete;
    bool operator!() const = delete;
    bool operator&&(const SequenceNumber<NUMERIC_TYPE, SIGNED_TYPE>&) const = delete;
    bool operator||(const SequenceNumber<NUMERIC_TYPE, SIGNED_TYPE>&) const = delete;
    SequenceNumber<NUMERIC_TYPE, SIGNED_TYPE> operator~() const = delete;
    SequenceNumber<NUMERIC_TYPE, SIGNED_TYPE> operator&(
        const SequenceNumber<NUMERIC_TYPE, SIGNED_TYPE>&) const = delete;
    SequenceNumber<NUMERIC_TYPE, SIGNED_TYPE> operator|(
        const SequenceNumber<NUMERIC_TYPE, SIGNED_TYPE>&) const = delete;
    SequenceNumber<NUMERIC_TYPE, SIGNED_TYPE> operator^(
        const SequenceNumber<NUMERIC_TYPE, SIGNED_TYPE>&) const = delete;
    SequenceNumber<NUMERIC_TYPE, SIGNED_TYPE> operator<<(
        const SequenceNumber<NUMERIC_TYPE, SIGNED_TYPE>&) const = delete;
    SequenceNumber<NUMERIC_TYPE, SIGNED_TYPE> operator>>(
        const SequenceNumber<NUMERIC_TYPE, SIGNED_TYPE>&) const = delete;
    int operator*() = delete;
    // SequenceNumber<NUMERIC_TYPE, SIGNED_TYPE>* operator& () = delete;
 
  private:
    NUMERIC_TYPE m_value; 
};
 
template <typename NUMERIC_TYPE, typename SIGNED_TYPE>
std::ostream&
operator<<(std::ostream& os, const SequenceNumber<NUMERIC_TYPE, SIGNED_TYPE>& val)
{
    os << val.m_value;
    return os;
}
 
template <typename NUMERIC_TYPE, typename SIGNED_TYPE>
std::istream&
operator>>(std::istream& is, const SequenceNumber<NUMERIC_TYPE, SIGNED_TYPE>& val)
{
    is >> val.m_value;
    return is;
}
 
typedef SequenceNumber<uint32_t, int32_t> SequenceNumber32;
typedef SequenceNumber<uint16_t, int16_t> SequenceNumber16;
typedef SequenceNumber<uint8_t, int8_t> SequenceNumber8;
 
namespace TracedValueCallback
{
 
typedef void (*SequenceNumber32)(SequenceNumber32 oldValue, SequenceNumber32 newValue);
 
} // namespace TracedValueCallback
 
TYPENAMEGET_DEFINE(SequenceNumber32);
 
} // namespace ns3
 
#endif /* NS3_SEQ_NUM_H */