[apple/xnu.git] / iokit / IOKit / IOBufferMemoryDescriptor.h

/*
 * Copyright (c) 1998-2000 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
 * 
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. The rights granted to you under the License
 * may not be used to create, or enable the creation or redistribution of,
 * unlawful or unlicensed copies of an Apple operating system, or to
 * circumvent, violate, or enable the circumvention or violation of, any
 * terms of an Apple operating system software license agreement.
 * 
 * Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this file.
 * 
 * The 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, QUIET ENJOYMENT OR NON-INFRINGEMENT.
 * Please see the License for the specific language governing rights and
 * limitations under the License.
 * 
 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
 */
#ifndef _IOBUFFERMEMORYDESCRIPTOR_H
#define _IOBUFFERMEMORYDESCRIPTOR_H

#include <IOKit/IOMemoryDescriptor.h>

enum {
    kIOMemoryPhysicallyContiguous	= 0x00000010,
    kIOMemoryPageable	      		= 0x00000020,
    kIOMemoryPurgeable	      		= 0x00000040,
    kIOMemorySharingTypeMask		= 0x000f0000,
    kIOMemoryUnshared			= 0x00000000,
    kIOMemoryKernelUserShared		= 0x00010000
};

#define _IOBUFFERMEMORYDESCRIPTOR_INTASKWITHOPTIONS_	1
/*!
    @class IOBufferMemoryDescriptor
    @abstract Provides a simple memory descriptor that allocates its own buffer memory.
*/

class IOBufferMemoryDescriptor : public IOGeneralMemoryDescriptor
{
    OSDeclareDefaultStructors(IOBufferMemoryDescriptor);

private:
/*! @struct ExpansionData
    @discussion This structure will be used to expand the capablilties of this class in the future.
    */    
    struct ExpansionData {
	IOMemoryMap *   map;
    };

/*! @var reserved
    Reserved for future use.  (Internal use only)  */
    ExpansionData * reserved;

protected:
    void *               _buffer;
    vm_size_t            _capacity;
    vm_offset_t		 _alignment;
    IOOptionBits	 _options;
    IOPhysicalAddress *  _physAddrs;
    unsigned             _physSegCount;

private:
    virtual bool initWithOptions(
                               IOOptionBits options,
                               vm_size_t    capacity,
                               vm_offset_t  alignment,
			       task_t	    inTask);

    virtual bool initWithPhysicalMask(
				task_t		  inTask,
				IOOptionBits      options,
				mach_vm_size_t    capacity,
				mach_vm_address_t alignment,
				mach_vm_address_t physicalMask);

    OSMetaClassDeclareReservedUsed(IOBufferMemoryDescriptor, 0);
    OSMetaClassDeclareReservedUsed(IOBufferMemoryDescriptor, 1);
    OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 2);
    OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 3);
    OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 4);
    OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 5);
    OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 6);
    OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 7);
    OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 8);
    OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 9);
    OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 10);
    OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 11);
    OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 12);
    OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 13);
    OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 14);
    OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 15);

protected:
    virtual void free();

    virtual bool initWithAddress( void *      address,       /* not supported */
                                  IOByteCount withLength,
                                  IODirection withDirection );

    virtual bool initWithAddress( vm_address_t address,      /* not supported */
                                  IOByteCount  withLength,
                                  IODirection  withDirection,
                                  task_t       withTask );

    virtual bool initWithPhysicalAddress( 
                                  IOPhysicalAddress address, /* not supported */
                                  IOByteCount       withLength,
                                  IODirection       withDirection );

    virtual bool initWithPhysicalRanges( 
                                  IOPhysicalRange * ranges,  /* not supported */
                                  UInt32            withCount,
                                  IODirection       withDirection,
                                  bool              asReference = false );

    virtual bool initWithRanges(  IOVirtualRange * ranges,   /* not supported */
                                  UInt32           withCount,
                                  IODirection      withDirection,
                                  task_t           withTask,
                                  bool             asReference = false );

    IOGeneralMemoryDescriptor::withAddress;                  /* not supported */
    IOGeneralMemoryDescriptor::withPhysicalAddress;          /* not supported */
    IOGeneralMemoryDescriptor::withPhysicalRanges;           /* not supported */
    IOGeneralMemoryDescriptor::withRanges;                   /* not supported */
    IOGeneralMemoryDescriptor::withSubRange;                 /* not supported */

public:

    /*
     * withOptions:
     *
     * Returns a new IOBufferMemoryDescriptor with a buffer large enough to
     * hold capacity bytes.  The descriptor's length is initially set to the
     * capacity.
     */
    virtual bool initWithOptions(   IOOptionBits options,
                                    vm_size_t    capacity,
                                    vm_offset_t  alignment);

    static IOBufferMemoryDescriptor * withOptions(  IOOptionBits options,
                                                    vm_size_t    capacity,
                                                    vm_offset_t  alignment = 1);

/*! @function inTaskWithOptions
    @abstract Creates a memory buffer with memory descriptor for that buffer. 
    @discussion Added in Mac OS X 10.2, this method allocates a memory buffer with a given size and alignment in the task's address space specified, and returns a memory descriptor instance representing the memory. It is recommended that memory allocated for I/O or sharing via mapping be created via IOBufferMemoryDescriptor. Options passed with the request specify the kind of memory to be allocated - pageablity and sharing are specified with option bits. This function may block and so should not be called from interrupt level or while a simple lock is held.
    @param inTask The task the buffer will be allocated in.
    @param options Options for the allocation:<br>
    kIODirectionOut, kIODirectionIn - set the direction of the I/O transfer.<br>
    kIOMemoryPhysicallyContiguous - pass to request memory be physically contiguous. This option is heavily discouraged. The request may fail if memory is fragmented, may cause large amounts of paging activity, and may take a very long time to execute.<br>
    kIOMemoryPageable - pass to request memory be non-wired - the default for kernel allocated memory is wired.<br>
    kIOMemoryPurgeable - pass to request memory that may later have its purgeable state set with IOMemoryDescriptor::setPurgeable. Only supported for kIOMemoryPageable allocations.<br>
    kIOMemoryKernelUserShared - pass to request memory that will be mapped into both the kernel and client applications.
    @param capacity The number of bytes to allocate.
    @param alignment The minimum required alignment of the buffer in bytes - 1 is the default for no required alignment. For example, pass 256 to get memory allocated at an address with bits 0-7 zero.
    @result Returns an instance of class IOBufferMemoryDescriptor to be released by the caller, which will free the memory desriptor and associated buffer. */

    static IOBufferMemoryDescriptor * inTaskWithOptions(
					    task_t       inTask,
                                            IOOptionBits options,
                                            vm_size_t    capacity,
                                            vm_offset_t  alignment = 1);

/*! @function inTaskWithPhysicalMask
    @abstract Creates a memory buffer with memory descriptor for that buffer. 
    @discussion Added in Mac OS X 10.5, this method allocates a memory buffer with a given size and alignment in the task's address space specified, and returns a memory descriptor instance representing the memory. It is recommended that memory allocated for I/O or sharing via mapping be created via IOBufferMemoryDescriptor. Options passed with the request specify the kind of memory to be allocated - pageablity and sharing are specified with option bits. This function may block and so should not be called from interrupt level or while a simple lock is held.
    @param inTask The task the buffer will be mapped in. Pass NULL to create memory unmapped in any task (eg. for use as a DMA buffer).
    @param options Options for the allocation:<br>
    kIODirectionOut, kIODirectionIn - set the direction of the I/O transfer.<br>
    kIOMemoryPhysicallyContiguous - pass to request memory be physically contiguous. This option is heavily discouraged. The request may fail if memory is fragmented, may cause large amounts of paging activity, and may take a very long time to execute.<br>
    kIOMemoryKernelUserShared - pass to request memory that will be mapped into both the kernel and client applications.
    @param capacity The number of bytes to allocate.
    @param mask The buffer will be allocated with pages such that physical addresses will only have bits set present in physicalMask. For example, pass 0x00000000FFFFFFFFULL for a buffer to be accessed by hardware that has 32 address bits.
    @result Returns an instance of class IOBufferMemoryDescriptor to be released by the caller, which will free the memory desriptor and associated buffer. */

    static IOBufferMemoryDescriptor * inTaskWithPhysicalMask(
					    task_t	      inTask,
                                            IOOptionBits      options,
                                            mach_vm_size_t    capacity,
                                            mach_vm_address_t physicalMask);

    /*
     * withCapacity:
     *
     * Returns a new IOBufferMemoryDescriptor with a buffer large enough to
     * hold capacity bytes.  The descriptor's length is initially set to the
     * capacity.
     */
    static IOBufferMemoryDescriptor * withCapacity(
                                     vm_size_t    capacity,
                                     IODirection  withDirection,
                                     bool         withContiguousMemory = false);
    /*
     * initWithBytes:
     *
     * Initialize a new IOBufferMemoryDescriptor preloaded with bytes (copied).
     * The descriptor's length and capacity are set to the input buffer's size.
     */
    virtual bool initWithBytes(const void * bytes,
                               vm_size_t    withLength,
                               IODirection  withDirection,
                               bool         withContiguousMemory = false);

    /*
     * withBytes:
     *
     * Returns a new IOBufferMemoryDescriptor preloaded with bytes (copied).
     * The descriptor's length and capacity are set to the input buffer's size.
     */
    static IOBufferMemoryDescriptor * withBytes(
                                     const void * bytes,
                                     vm_size_t    withLength,
                                     IODirection  withDirection,
                                     bool         withContiguousMemory = false);

    /*
     * setLength:
     *
     * Change the buffer length of the memory descriptor.  When a new buffer
     * is created, the initial length of the buffer is set to be the same as
     * the capacity.  The length can be adjusted via setLength for a shorter
     * transfer (there is no need to create more buffer descriptors when you
     * can reuse an existing one, even for different transfer sizes).   Note
     * that the specified length must not exceed the capacity of the buffer.
     */
    virtual void setLength(vm_size_t length);

    /*
     * setDirection:
     *
     * Change the direction of the transfer.  This method allows one to redirect
     * the descriptor's transfer direction.  This eliminates the need to destroy
     * and create new buffers when different transfer directions are needed.
     */
    virtual void setDirection(IODirection direction);

    /*
     * getCapacity:
     *
     * Get the buffer capacity
     */
    virtual vm_size_t getCapacity() const;

    /*
     * getBytesNoCopy:
     *
     * Return the virtual address of the beginning of the buffer
     */
    virtual void *getBytesNoCopy();

    /*
     * getBytesNoCopy:
     *
     * Return the virtual address of an offset from the beginning of the buffer
     */
    virtual void *getBytesNoCopy(vm_size_t start, vm_size_t withLength);

    /*
     * appendBytes:
     *
     * Add some data to the end of the buffer.  This method automatically
     * maintains the memory descriptor buffer length.  Note that appendBytes
     * will not copy past the end of the memory descriptor's current capacity.
     */
    virtual bool appendBytes(const void *bytes, vm_size_t withLength);

    /* DEPRECATED */ virtual void * getVirtualSegment(IOByteCount offset,
    /* DEPRECATED */					IOByteCount * length);
};

#endif /* !_IOBUFFERMEMORYDESCRIPTOR_H */
Commit	Line	Data
1c79356b A	1	/*
	2	* Copyright (c) 1998-2000 Apple Computer, Inc. All rights reserved.
	3	*
2d21ac55	4	* @APPLE_OSREFERENCE_LICENSE_HEADER_START@
1c79356b	5	*
2d21ac55 A	6	* This file contains Original Code and/or Modifications of Original Code
	7	* as defined in and that are subject to the Apple Public Source License
	8	* Version 2.0 (the 'License'). You may not use this file except in
	9	* compliance with the License. The rights granted to you under the License
	10	* may not be used to create, or enable the creation or redistribution of,
	11	* unlawful or unlicensed copies of an Apple operating system, or to
	12	* circumvent, violate, or enable the circumvention or violation of, any
	13	* terms of an Apple operating system software license agreement.
8f6c56a5	14	*
2d21ac55 A	15	* Please obtain a copy of the License at
	16	* http://www.opensource.apple.com/apsl/ and read it before using this file.
	17	*
	18	* The Original Code and all software distributed under the License are
	19	* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
8f6c56a5 A	20	* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
8f6c56a5 A	21	* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
2d21ac55 A	22	* FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
	23	* Please see the License for the specific language governing rights and
	24	* limitations under the License.
8f6c56a5	25	*
2d21ac55	26	* @APPLE_OSREFERENCE_LICENSE_HEADER_END@
1c79356b A	27	*/
	28	#ifndef _IOBUFFERMEMORYDESCRIPTOR_H
	29	#define _IOBUFFERMEMORYDESCRIPTOR_H
	30
	31	#include <IOKit/IOMemoryDescriptor.h>
	32
	33	enum {
1c79356b A	34	kIOMemoryPhysicallyContiguous = 0x00000010,
1c79356b A	35	kIOMemoryPageable = 0x00000020,
91447636	36	kIOMemoryPurgeable = 0x00000040,
1c79356b A	37	kIOMemorySharingTypeMask = 0x000f0000,
1c79356b A	38	kIOMemoryUnshared = 0x00000000,
55e303ae	39	kIOMemoryKernelUserShared = 0x00010000
1c79356b A	40	};
1c79356b A	41
9bccf70c	42	#define _IOBUFFERMEMORYDESCRIPTOR_INTASKWITHOPTIONS_ 1
91447636 A	43	/*!
	44	@class IOBufferMemoryDescriptor
	45	@abstract Provides a simple memory descriptor that allocates its own buffer memory.
	46	*/
1c79356b A	47
	48	class IOBufferMemoryDescriptor : public IOGeneralMemoryDescriptor
	49	{
	50	OSDeclareDefaultStructors(IOBufferMemoryDescriptor);
	51
2d21ac55	52	private:
1c79356b A	53	/*! @struct ExpansionData
	54	@discussion This structure will be used to expand the capablilties of this class in the future.
	55	*/
9bccf70c	56	struct ExpansionData {
2d21ac55	57	IOMemoryMap * map;
9bccf70c	58	};
1c79356b A	59
	60	/*! @var reserved
	61	Reserved for future use. (Internal use only) */
	62	ExpansionData * reserved;
	63
	64	protected:
	65	void * _buffer;
	66	vm_size_t _capacity;
	67	vm_offset_t _alignment;
	68	IOOptionBits _options;
	69	IOPhysicalAddress * _physAddrs;
	70	unsigned _physSegCount;
	71
	72	private:
9bccf70c A	73	virtual bool initWithOptions(
	74	IOOptionBits options,
	75	vm_size_t capacity,
	76	vm_offset_t alignment,
	77	task_t inTask);
0c530ab8	78
0c530ab8 A	79	virtual bool initWithPhysicalMask(
	80	task_t inTask,
	81	IOOptionBits options,
	82	mach_vm_size_t capacity,
	83	mach_vm_address_t alignment,
	84	mach_vm_address_t physicalMask);
2d21ac55 A	85
2d21ac55 A	86	OSMetaClassDeclareReservedUsed(IOBufferMemoryDescriptor, 0);
0c530ab8	87	OSMetaClassDeclareReservedUsed(IOBufferMemoryDescriptor, 1);
1c79356b A	88	OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 2);
	89	OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 3);
	90	OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 4);
	91	OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 5);
	92	OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 6);
	93	OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 7);
	94	OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 8);
	95	OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 9);
	96	OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 10);
	97	OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 11);
	98	OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 12);
	99	OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 13);
	100	OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 14);
	101	OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 15);
	102
	103	protected:
	104	virtual void free();
	105
	106	virtual bool initWithAddress( void * address, /* not supported */
	107	IOByteCount withLength,
	108	IODirection withDirection );
	109
	110	virtual bool initWithAddress( vm_address_t address, /* not supported */
	111	IOByteCount withLength,
	112	IODirection withDirection,
	113	task_t withTask );
	114
	115	virtual bool initWithPhysicalAddress(
	116	IOPhysicalAddress address, /* not supported */
	117	IOByteCount withLength,
	118	IODirection withDirection );
	119
	120	virtual bool initWithPhysicalRanges(
	121	IOPhysicalRange * ranges, /* not supported */
	122	UInt32 withCount,
	123	IODirection withDirection,
	124	bool asReference = false );
	125
	126	virtual bool initWithRanges( IOVirtualRange * ranges, /* not supported */
	127	UInt32 withCount,
	128	IODirection withDirection,
	129	task_t withTask,
	130	bool asReference = false );
	131
	132	IOGeneralMemoryDescriptor::withAddress; /* not supported */
	133	IOGeneralMemoryDescriptor::withPhysicalAddress; /* not supported */
	134	IOGeneralMemoryDescriptor::withPhysicalRanges; /* not supported */
	135	IOGeneralMemoryDescriptor::withRanges; /* not supported */
	136	IOGeneralMemoryDescriptor::withSubRange; /* not supported */
	137
	138	public:
	139
	140	/*
	141	* withOptions:
	142	*
	143	* Returns a new IOBufferMemoryDescriptor with a buffer large enough to
	144	* hold capacity bytes. The descriptor's length is initially set to the
	145	* capacity.
	146	*/
	147	virtual bool initWithOptions( IOOptionBits options,
	148	vm_size_t capacity,
	149	vm_offset_t alignment);
	150
	151	static IOBufferMemoryDescriptor * withOptions( IOOptionBits options,
152	vm_size_t capacity,
153	vm_offset_t alignment = 1);
154
9bccf70c	155	/*! @function inTaskWithOptions
91447636 A	156	@abstract Creates a memory buffer with memory descriptor for that buffer.
91447636 A	157	@discussion Added in Mac OS X 10.2, this method allocates a memory buffer with a given size and alignment in the task's address space specified, and returns a memory descriptor instance representing the memory. It is recommended that memory allocated for I/O or sharing via mapping be created via IOBufferMemoryDescriptor. Options passed with the request specify the kind of memory to be allocated - pageablity and sharing are specified with option bits. This function may block and so should not be called from interrupt level or while a simple lock is held.
9bccf70c	158	@param inTask The task the buffer will be allocated in.
91447636	159	@param options Options for the allocation:<br>
0c530ab8	160	kIODirectionOut, kIODirectionIn - set the direction of the I/O transfer.<br>
91447636 A	161	kIOMemoryPhysicallyContiguous - pass to request memory be physically contiguous. This option is heavily discouraged. The request may fail if memory is fragmented, may cause large amounts of paging activity, and may take a very long time to execute.<br>
	162	kIOMemoryPageable - pass to request memory be non-wired - the default for kernel allocated memory is wired.<br>
	163	kIOMemoryPurgeable - pass to request memory that may later have its purgeable state set with IOMemoryDescriptor::setPurgeable. Only supported for kIOMemoryPageable allocations.<br>
9bccf70c A	164	kIOMemoryKernelUserShared - pass to request memory that will be mapped into both the kernel and client applications.
	165	@param capacity The number of bytes to allocate.
	166	@param alignment The minimum required alignment of the buffer in bytes - 1 is the default for no required alignment. For example, pass 256 to get memory allocated at an address with bits 0-7 zero.
91447636	167	@result Returns an instance of class IOBufferMemoryDescriptor to be released by the caller, which will free the memory desriptor and associated buffer. */
9bccf70c A	168
	169	static IOBufferMemoryDescriptor * inTaskWithOptions(
	170	task_t inTask,
	171	IOOptionBits options,
	172	vm_size_t capacity,
	173	vm_offset_t alignment = 1);
	174
0c530ab8 A	175	/*! @function inTaskWithPhysicalMask
	176	@abstract Creates a memory buffer with memory descriptor for that buffer.
	177	@discussion Added in Mac OS X 10.5, this method allocates a memory buffer with a given size and alignment in the task's address space specified, and returns a memory descriptor instance representing the memory. It is recommended that memory allocated for I/O or sharing via mapping be created via IOBufferMemoryDescriptor. Options passed with the request specify the kind of memory to be allocated - pageablity and sharing are specified with option bits. This function may block and so should not be called from interrupt level or while a simple lock is held.
	178	@param inTask The task the buffer will be mapped in. Pass NULL to create memory unmapped in any task (eg. for use as a DMA buffer).
	179	@param options Options for the allocation:<br>
	180	kIODirectionOut, kIODirectionIn - set the direction of the I/O transfer.<br>
	181	kIOMemoryPhysicallyContiguous - pass to request memory be physically contiguous. This option is heavily discouraged. The request may fail if memory is fragmented, may cause large amounts of paging activity, and may take a very long time to execute.<br>
	182	kIOMemoryKernelUserShared - pass to request memory that will be mapped into both the kernel and client applications.
	183	@param capacity The number of bytes to allocate.
	184	@param mask The buffer will be allocated with pages such that physical addresses will only have bits set present in physicalMask. For example, pass 0x00000000FFFFFFFFULL for a buffer to be accessed by hardware that has 32 address bits.
	185	@result Returns an instance of class IOBufferMemoryDescriptor to be released by the caller, which will free the memory desriptor and associated buffer. */
	186
	187	static IOBufferMemoryDescriptor * inTaskWithPhysicalMask(
	188	task_t inTask,
	189	IOOptionBits options,
	190	mach_vm_size_t capacity,
	191	mach_vm_address_t physicalMask);
0c530ab8	192
1c79356b A	193	/*
	194	* withCapacity:
	195	*
	196	* Returns a new IOBufferMemoryDescriptor with a buffer large enough to
	197	* hold capacity bytes. The descriptor's length is initially set to the
	198	* capacity.
	199	*/
	200	static IOBufferMemoryDescriptor * withCapacity(
	201	vm_size_t capacity,
	202	IODirection withDirection,
	203	bool withContiguousMemory = false);
	204	/*
	205	* initWithBytes:
	206	*
	207	* Initialize a new IOBufferMemoryDescriptor preloaded with bytes (copied).
	208	* The descriptor's length and capacity are set to the input buffer's size.
	209	*/
	210	virtual bool initWithBytes(const void * bytes,
	211	vm_size_t withLength,
	212	IODirection withDirection,
	213	bool withContiguousMemory = false);
	214
	215	/*
	216	* withBytes:
	217	*
	218	* Returns a new IOBufferMemoryDescriptor preloaded with bytes (copied).
	219	* The descriptor's length and capacity are set to the input buffer's size.
	220	*/
	221	static IOBufferMemoryDescriptor * withBytes(
	222	const void * bytes,
	223	vm_size_t withLength,
	224	IODirection withDirection,
	225	bool withContiguousMemory = false);
	226
	227	/*
	228	* setLength:
	229	*
	230	* Change the buffer length of the memory descriptor. When a new buffer
	231	* is created, the initial length of the buffer is set to be the same as
	232	* the capacity. The length can be adjusted via setLength for a shorter
	233	* transfer (there is no need to create more buffer descriptors when you
	234	* can reuse an existing one, even for different transfer sizes). Note
	235	* that the specified length must not exceed the capacity of the buffer.
	236	*/
	237	virtual void setLength(vm_size_t length);
	238
	239	/*
	240	* setDirection:
	241	*
	242	* Change the direction of the transfer. This method allows one to redirect
	243	* the descriptor's transfer direction. This eliminates the need to destroy
	244	* and create new buffers when different transfer directions are needed.
	245	*/
	246	virtual void setDirection(IODirection direction);
	247
	248	/*
	249	* getCapacity:
	250	*
	251	* Get the buffer capacity
	252	*/
	253	virtual vm_size_t getCapacity() const;
	254
	255	/*
	256	* getBytesNoCopy:
257	*
258	* Return the virtual address of the beginning of the buffer
259	*/
260	virtual void *getBytesNoCopy();
261
262	/*
263	* getBytesNoCopy:
264	*
265	* Return the virtual address of an offset from the beginning of the buffer
266	*/
267	virtual void *getBytesNoCopy(vm_size_t start, vm_size_t withLength);
268
269	/*
270	* appendBytes:
271	*
272	* Add some data to the end of the buffer. This method automatically
273	* maintains the memory descriptor buffer length. Note that appendBytes
274	* will not copy past the end of the memory descriptor's current capacity.
275	*/
276	virtual bool appendBytes(const void *bytes, vm_size_t withLength);
0c530ab8	277
0c530ab8 A	278	/* DEPRECATED / virtual void getVirtualSegment(IOByteCount offset,
0c530ab8 A	279	/* DEPRECATED / IOByteCount length);
1c79356b A	280	};
	281
	282	#endif /* !_IOBUFFERMEMORYDESCRIPTOR_H */