xnu-792.6.61.tar.gz

[apple/xnu.git] / iokit / Kernel / IORangeAllocator.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
 * License.  Please obtain a copy of the License at
 * http://www.apple.com/publicsource and read it before using this file.
 * 
 * This Original Code and all software distributed under the License are
 * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
 * License for the specific language governing rights and limitations
 * under the License.
 * 
 * @APPLE_LICENSE_HEADER_END@
 */
/*
 * Copyright (c) 1999 Apple Computer, Inc.
 *
 *
 * HISTORY
 *
 * sdouglas 05 Nov 99 - created.
 */

#include <libkern/c++/OSArray.h>
#include <libkern/c++/OSNumber.h>
#include <IOKit/IORangeAllocator.h>
#include <IOKit/IOLib.h>
#include <IOKit/IOLocks.h>
#include <IOKit/assert.h>

/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */

#undef super
#define super OSObject

OSDefineMetaClassAndStructors( IORangeAllocator, OSObject )

struct IORangeAllocatorElement {
    // closed range
    IORangeScalar	start;
    IORangeScalar	end;
};

IOLock *	gIORangeAllocatorLock;

#define LOCK()		\
	if( options & kLocking)	IOTakeLock( gIORangeAllocatorLock )
#define UNLOCK()	\
	if( options & kLocking)	IOUnlock( gIORangeAllocatorLock )

/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */

bool IORangeAllocator::init( IORangeScalar endOfRange,
				IORangeScalar _defaultAlignment,
				UInt32 _capacity,
				IOOptionBits _options )
{
    if( !super::init())
	return( false );

    if( !_capacity)
	_capacity = 1;
    if( !_defaultAlignment)
	_defaultAlignment = 1;
    capacity		= 0;
    capacityIncrement	= _capacity;
    numElements 	= 0;
    elements 		= 0;
    defaultAlignmentMask = _defaultAlignment - 1;
    options		= _options;

    if( (!gIORangeAllocatorLock) && (options & kLocking))
	gIORangeAllocatorLock = IOLockAlloc();

    if( endOfRange)
	deallocate( 0, endOfRange + 1 );

    return( true );
}

IORangeAllocator * IORangeAllocator:: withRange(
					IORangeScalar endOfRange,
				        IORangeScalar defaultAlignment,
				        UInt32 capacity,
					IOOptionBits options )
{
    IORangeAllocator * thingy;

    thingy = new IORangeAllocator;
    if( thingy && ! thingy->init( endOfRange, defaultAlignment,
				capacity, options )) {
	thingy->release();
	thingy = 0;
    }

    return( thingy );
}

void IORangeAllocator::free()
{
    if( elements)
	IODelete( elements, IORangeAllocatorElement, capacity );

    super::free();
}

UInt32 IORangeAllocator::getFragmentCount( void )
{
    return( numElements );
}

UInt32 IORangeAllocator::getFragmentCapacity( void )
{
    return( capacity );
}

void IORangeAllocator::setFragmentCapacityIncrement( UInt32 count )
{
    capacityIncrement = count;
}


// allocate element at index
bool IORangeAllocator::allocElement( UInt32 index )
{
    UInt32			newCapacity;
    IORangeAllocatorElement *	newElements;

    if( ((numElements == capacity) && capacityIncrement)
     || (!elements)) {

	newCapacity = capacity + capacityIncrement;
	newElements = IONew( IORangeAllocatorElement, newCapacity );
	if( !newElements)
	    return( false );

	if( elements) {
	    bcopy( elements,
		   newElements,
		   index * sizeof( IORangeAllocatorElement));
	    bcopy( elements + index,
		   newElements + index + 1,
		   (numElements - index) * sizeof( IORangeAllocatorElement));

	    IODelete( elements, IORangeAllocatorElement, capacity );
	}

	elements = newElements;
	capacity = newCapacity;

    } else {

	bcopy( elements + index,
	       elements + index + 1,
	       (numElements - index) * sizeof( IORangeAllocatorElement));
    }
    numElements++;

    return( true );
}

// destroy element at index
void IORangeAllocator::deallocElement( UInt32 index )
{
    numElements--;
    bcopy( elements + index + 1,
	   elements + index,
	   (numElements - index) * sizeof( IORangeAllocatorElement));
}

bool IORangeAllocator::allocate( IORangeScalar size,
				 IORangeScalar * result,
				 IORangeScalar alignment )
{
    IORangeScalar	data, dataEnd;
    IORangeScalar	thisStart, thisEnd;
    UInt32		index;
    bool		ok = false;

    if( !size || !result)
	return( false );

    if( 0 == alignment)
	alignment = defaultAlignmentMask;
    else
        alignment--;

    size = (size + defaultAlignmentMask) & ~defaultAlignmentMask;

    LOCK();

    for( index = 0; index < numElements; index++ ) {

	thisStart = elements[index].start;
	thisEnd = elements[index].end;
        data = (thisStart + alignment) & ~alignment;
	dataEnd = (data + size - 1);

	ok = (dataEnd <= thisEnd);
	if( ok) {
	    if( data != thisStart) {
		if( dataEnd != thisEnd) {
		    if( allocElement( index + 1 )) {
			elements[index++].end = data - 1;
			elements[index].start = dataEnd + 1;
			elements[index].end = thisEnd;
		    } else
			ok = false;
		} else
		    elements[index].end = data - 1;
	    } else {
		if( dataEnd != thisEnd)
		    elements[index].start = dataEnd + 1;
		else
		    deallocElement( index );
	    }
	    if( ok)
		*result = data;
      	    break;
	} 
    }

    UNLOCK();

    return( ok );
}

bool IORangeAllocator::allocateRange( IORangeScalar data,
					 IORangeScalar size )
{
    IORangeScalar	thisStart, thisEnd;
    IORangeScalar	dataEnd;
    UInt32		index;
    bool		found = false;

    if( !size)
	return( 0 );

    size = (size + defaultAlignmentMask) & ~defaultAlignmentMask;
    dataEnd = data + size - 1;

    LOCK();

    for( index = 0;
	 (!found) && (index < numElements);
	 index++ ) {

	thisStart = elements[index].start;
	thisEnd = elements[index].end;

	if( thisStart > data)
	    break;
	found = (dataEnd <= thisEnd);

        if( found) {
	    if( data != thisStart) {
	        if( dataEnd != thisEnd) {
		    found = allocElement( index + 1 );
		    if( found) {
		        elements[index++].end = data - 1;
		        elements[index].start = dataEnd + 1;
		        elements[index].end = thisEnd;
		    }
	        } else
	       	    elements[index].end = data - 1;
	    } else if( dataEnd != thisEnd)
      	        elements[index].start = dataEnd + 1;
	    else
	        deallocElement( index );
        }
    }

    UNLOCK();

    return( found );
}

void IORangeAllocator::deallocate( IORangeScalar data,
				   IORangeScalar size )
{
    IORangeScalar	dataEnd;
    UInt32		index;
    bool		headContig = false;
    bool		tailContig = false;

    size = (size + defaultAlignmentMask) & ~defaultAlignmentMask;
    dataEnd = data + size - 1;

    LOCK();

    for( index = 0; index < numElements; index++ ) {
	if( elements[index].start < data) {
	    headContig = (data <= (elements[index].end + 1));
	    continue;
	}
	tailContig = ((data + size) >= elements[index].start);
	break;
    }

    if( headContig) {
        if( tailContig) {
            elements[index-1].end = elements[index].end;
	    deallocElement( index );
	} else /*safe*/ if( dataEnd > elements[index-1].end)
	    elements[index-1].end = dataEnd;

    } else if( tailContig) {
	if( data < elements[index].start) /*safe*/
	    elements[index].start = data;

    } else if( allocElement( index)) {
	elements[index].start = data;
	elements[index].end = dataEnd;
    }

    UNLOCK();
}

bool IORangeAllocator::serialize(OSSerialize *s) const
{
    OSArray *	array = OSArray::withCapacity( numElements * 2 );
    OSNumber *	num;
    UInt32	index;
    bool	ret;

    if( !array)
	return( false );

    LOCK();

    for( index = 0; index < numElements; index++) {
	if( (num = OSNumber::withNumber( elements[index].start,
					8 * sizeof(IORangeScalar) ))) {
	    array->setObject(num);
	    num->release();
	}
	if( (num = OSNumber::withNumber( elements[index].end,
					8 * sizeof(IORangeScalar) ))) {
	    array->setObject(num);
	    num->release();
	}
    }

    UNLOCK();

    ret = array->serialize(s);
    array->release();

    return( ret );
}

IORangeScalar IORangeAllocator::getFreeCount( void )
{
    UInt32		index;
    IORangeScalar	sum = 0;

    for( index = 0; index < numElements; index++)
	sum += elements[index].end - elements[index].start + 1;

    return( sum );
}