Source to iokit/Families/IONetworking/IOPacketQueue.cpp

/*
 * Copyright (c) 1998-2000 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_LICENSE_HEADER_START@
 * 
 * The contents of this file constitute Original Code as defined in and
 * are subject to the Apple Public Source License Version 1.1 (the
 * "License").  You may not use this file except in compliance with the
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/*
 * Copyright (c) 1998 Apple Computer, Inc.  All rights reserved. 
 *
 * IOPacketQueue.cpp - Implements a FIFO mbuf packet queue.
 *
 * HISTORY
 * 9-Dec-1998       Joe Liu (jliu) created.
 *
 */

#include <IOKit/assert.h>
#include <IOKit/IOLib.h>    // IOLog
#include <IOKit/network/IOPacketQueue.h>

// Get the mbuf definitions from BSD headers.
//
extern "C" {
#include <sys/param.h>
#include <sys/mbuf.h>
}

#define super OSObject
OSDefineMetaClassAndStructors( IOPacketQueue, OSObject )

//---------------------------------------------------------------------------
// Lock macros.

#define LOCK         IOSimpleLockLock(_lock)
#define UNLOCK       IOSimpleLockUnlock(_lock)

//---------------------------------------------------------------------------
// Factory method that will construct and initialize an IOPacketQueue instance.
//
// capacity: The initial capacity of the queue. Can be changed
//           later through setCapacity().
//
// Returns an IOPacketQueue instance upon success, or 0 otherwise.

bool IOPacketQueue::initWithCapacity(UInt32 capacity)
{
    _head = _tail = (struct mbuf *) 0;
    _size = _peakSize = 0;
    _capacity = capacity;

    if (!super::init()) {
        IOLog("IOPacketQueue: super::init() failed\n");
        return false;
    }

    if ((_lock = IOSimpleLockAlloc()) == 0)
        return false;

    IOSimpleLockInit(_lock);

    return true;
}

//---------------------------------------------------------------------------
// Factory method that will construct and initialize an IOPacketQueue instance.
//
// capacity: The initial capacity of the queue. Can be changed later
//           through setCapacity().
//
// Returns an IOPacketQueue instance on success, or 0 otherwise.

IOPacketQueue * IOPacketQueue::withCapacity(UInt32 capacity)
{
    IOPacketQueue * queue = new IOPacketQueue;

    if (queue && !queue->initWithCapacity(capacity)) {
        queue->release();
        return 0;
    }
    return queue;
}

//---------------------------------------------------------------------------
// Frees the IOPacketQueue instance. Release all packets in the queue to the
// free mbuf pool, then call super::free().

void IOPacketQueue::free()
{
    if (_lock) {
        setCapacity(0);
        lockFlush();
        IOSimpleLockFree(_lock);
    }
    super::free();
}

//---------------------------------------------------------------------------
// Get the size of the queue.
// Returns the number of packets currently held in the queue.

UInt32 IOPacketQueue::getSize() const
{
    return (_size);
}

//---------------------------------------------------------------------------
// The queue contains a counter that records the peak size of the queue.