pktfifo.hh

来自「M5,一个功能强大的多处理器系统模拟器.很多针对处理器架构,性能的研究都使用它作」· HH 代码 · 共 171 行

/*
 * Copyright (c) 2004, 2005
 * The Regents of The University of Michigan
 * All Rights Reserved
 *
 * This code is part of the M5 simulator.
 *
 * Permission is granted to use, copy, create derivative works and
 * redistribute this software and such derivative works for any
 * purpose, so long as the copyright notice above, this grant of
 * permission, and the disclaimer below appear in all copies made; and
 * so long as the name of The University of Michigan is not used in
 * any advertising or publicity pertaining to the use or distribution
 * of this software without specific, written prior authorization.
 *
 * THIS SOFTWARE IS PROVIDED AS IS, WITHOUT REPRESENTATION FROM THE
 * UNIVERSITY OF MICHIGAN AS TO ITS FITNESS FOR ANY PURPOSE, AND
 * WITHOUT WARRANTY BY THE UNIVERSITY OF MICHIGAN OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE. THE REGENTS OF THE UNIVERSITY OF MICHIGAN SHALL NOT BE
 * LIABLE FOR ANY DAMAGES, INCLUDING DIRECT, SPECIAL, INDIRECT,
 * INCIDENTAL, OR CONSEQUENTIAL DAMAGES, WITH RESPECT TO ANY CLAIM
 * ARISING OUT OF OR IN CONNECTION WITH THE USE OF THE SOFTWARE, EVEN
 * IF IT HAS BEEN OR IS HEREAFTER ADVISED OF THE POSSIBILITY OF SUCH
 * DAMAGES.
 *
 * Authors: Nathan L. Binkert
 */

#ifndef __DEV_PKTFIFO_HH__
#define __DEV_PKTFIFO_HH__

#include <iosfwd>
#include <list>
#include <string>

#include "dev/etherpkt.hh"
#include "sim/serialize.hh"

class Checkpoint;
class PacketFifo
{
  public:
    typedef std::list<EthPacketPtr> fifo_list;
    typedef fifo_list::iterator iterator;

  protected:
    std::list<EthPacketPtr> fifo;
    int _maxsize;
    int _size;
    int _reserved;

  public:
    explicit PacketFifo(int max) : _maxsize(max), _size(0), _reserved(0) {}
    virtual ~PacketFifo() {}

    int packets() const { return fifo.size(); }
    int maxsize() const { return _maxsize; }
    int size() const { return _size; }
    int reserved() const { return _reserved; }
    int avail() const { return _maxsize - _size - _reserved; }
    bool empty() const { return size() <= 0; }
    bool full() const { return avail() <= 0; }

    int reserve(int len = 0)
    {
        _reserved += len;
        assert(avail() >= 0);
        return _reserved;
    }

    iterator begin() { return fifo.begin(); }
    iterator end() { return fifo.end(); }

    EthPacketPtr front() { return fifo.front(); }

    bool push(EthPacketPtr ptr)
    {
        assert(ptr->length);
        assert(_reserved <= ptr->length);
        assert(ptr->slack == 0);
        if (avail() < ptr->length - _reserved)
            return false;

        _size += ptr->length;
        fifo.push_back(ptr);
        _reserved = 0;
        return true;
    }

    void pop()
    {
        if (empty())
            return;

        EthPacketPtr &packet = fifo.front();
        _size -= packet->length;
        _size -= packet->slack;
        packet->slack = 0;
        packet = NULL;
        fifo.pop_front();
    }

    void clear()
    {
        for (iterator i = begin(); i != end(); ++i)
            (*i)->slack = 0;
        fifo.clear();
        _size = 0;
        _reserved = 0;
    }

    void remove(iterator i)
    {
        EthPacketPtr &packet = *i;
        if (i != fifo.begin()) {
            iterator prev = i;
            --prev;
            assert(prev != fifo.end());
            (*prev)->slack += packet->length;
        } else {
            _size -= packet->length;
            _size -= packet->slack;
        }

        packet->slack = 0;
        packet = NULL;
        fifo.erase(i);
    }

    bool copyout(void *dest, int offset, int len);

    int countPacketsBefore(iterator end)
    {
        iterator i = fifo.begin();
        int count = 0;

        while (i != end) {
            ++count;
            ++i;
        }

        return count;
    }

    int countPacketsAfter(iterator i)
    {
        iterator end = fifo.end();
        int count = 0;

        while (i != end) {
            ++count;
            ++i;
        }

        return count;
    }


/**
 * Serialization stuff
 */
  public:
    void serialize(const std::string &base, std::ostream &os);
    void unserialize(const std::string &base,
                     Checkpoint *cp, const std::string &section);
};

#endif // __DEV_PKTFIFO_HH__