packet_storage.h

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// Copyright (C) 2012-2015 Internet Systems Consortium, Inc. ("ISC")
//
// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this
// file, You can obtain one at http://mozilla.org/MPL/2.0/.

#ifndef PACKET_STORAGE_H
#define PACKET_STORAGE_H

#include <boost/noncopyable.hpp>
#include <boost/shared_ptr.hpp>
#include <list>
#include <stdint.h>

namespace isc {
namespace perfdhcp {

template<typename T>
class PacketStorage : public boost::noncopyable {
public:
    typedef boost::shared_ptr<T> PacketPtr;

private:
    typedef typename std::list<PacketPtr> PacketContainer;
    typedef typename PacketContainer::iterator PacketContainerIterator;

public:

    PacketStorage() { }

    void append(const PacketPtr& packet) {
        storage_.push_back(packet);
        if (storage_.size() == 1) {
            current_pointer_ = storage_.begin();
        }
    }

    void clear(const uint64_t num = 0) {
        if (num != 0) {
            PacketContainerIterator last = storage_.begin();
            std::advance(last, num > size() ? size() : num);
            current_pointer_ = storage_.erase(storage_.begin(), last);
        } else {
            storage_.clear();
            current_pointer_ = storage_.begin();
        }
    }

    bool empty() const {
        return (storage_.empty());
    }

    PacketPtr getNext() {
        if (storage_.empty()) {
            return (PacketPtr());
        } else if (current_pointer_ == storage_.end()) {
            current_pointer_ = storage_.begin();
        }
        PacketPtr packet = *current_pointer_;
        current_pointer_ = storage_.erase(current_pointer_);
        return (packet);
    }

    PacketPtr getRandom() {
        if (empty()) {
            return (PacketPtr());
        }
        current_pointer_ = storage_.begin();
        if (size() > 1) {
            std::advance(current_pointer_, rand() % (size() - 1));
        }
        PacketPtr packet = *current_pointer_;
        current_pointer_ = storage_.erase(current_pointer_);
        return (packet);
    }

    uint64_t size() const {
        return (storage_.size());
    }

private:

    std::list<PacketPtr> storage_;            
    PacketContainerIterator current_pointer_; 

};

} // namespace perfdhcp
} // namespace isc

#endif // PACKET_STORAGE_H