/*
 * Copyright 2006, Haiku, Inc. All Rights Reserved.
 * Distributed under the terms of the MIT License.
 *
 * Authors:
 *		Axel Dörfler, axeld@pinc-software.de
 */
#ifndef BUFFER_QUEUE_H
#define BUFFER_QUEUE_H


#include "tcp.h"

#include <util/DoublyLinkedList.h>


typedef DoublyLinkedList<struct net_buffer, DoublyLinkedListCLink<struct net_buffer> > SegmentList;

class BufferQueue {
	public:
		BufferQueue(size_t maxBytes);
		~BufferQueue();

		void SetMaxBytes(size_t maxBytes);
		void SetInitialSequence(tcp_sequence sequence);

		void Add(net_buffer *buffer);
		void Add(net_buffer *buffer, tcp_sequence sequence);
		status_t RemoveUntil(tcp_sequence sequence);
		status_t Get(net_buffer *buffer, tcp_sequence sequence, size_t bytes);
		status_t Get(size_t bytes, bool remove, net_buffer **_buffer);

		size_t Available() const { return fContiguousBytes; }
		size_t Available(tcp_sequence sequence) const;

		size_t PushedData() const
		{
			// we must check if fPushPointer is not 0 here due to
			// `tcp_sequence's special handling of >
			return fPushPointer != 0 && fPushPointer > fFirstSequence ?
				fPushPointer - fFirstSequence : 0;
		}

		void SetPushPointer();

		size_t Used() const { return fNumBytes; }
		size_t Free() const { return fMaxBytes - fNumBytes; }
		size_t Size() const { return fMaxBytes; }

		bool IsContiguous() const { return fNumBytes == fContiguousBytes; }

		tcp_sequence FirstSequence() const { return fFirstSequence; }
		tcp_sequence LastSequence() const { return fLastSequence; }
		tcp_sequence NextSequence() const { return fFirstSequence + fContiguousBytes; }

	private:
		SegmentList fList;
		size_t	fMaxBytes;
		size_t	fNumBytes;
		size_t	fContiguousBytes;
		tcp_sequence fFirstSequence;
		tcp_sequence fLastSequence;
		tcp_sequence fPushPointer;
};

#endif	// BUFFER_QUEUE_H