/*

    File:       OTMemoryReserve.h

    Contains:   Wrapper for OTAllocMem to enable lots of interrupt-time memory allocations.

    Written by: Quinn "The Eskimo!"

    Copyright:  © 1998-2000 by Apple Computer, Inc., all rights reserved.

    Disclaimer: IMPORTANT:  This Apple software is supplied to you by Apple Computer, Inc.

                ("Apple") in consideration of your agreement to the following terms, and your

                use, installation, modification or redistribution of this Apple software

                constitutes acceptance of these terms.  If you do not agree with these terms,

                please do not use, install, modify or redistribute this Apple software.

                In consideration of your agreement to abide by the following terms, and subject

                to these terms, Apple grants you a personal, non-exclusive license, under AppleÕs

                copyrights in this original Apple software (the "Apple Software"), to use,

                reproduce, modify and redistribute the Apple Software, with or without

                modifications, in source and/or binary forms; provided that if you redistribute

                the Apple Software in its entirety and without modifications, you must retain

                this notice and the following text and disclaimers in all such redistributions of

                the Apple Software.  Neither the name, trademarks, service marks or logos of

                Apple Computer, Inc. may be used to endorse or promote products derived from the

                Apple Software without specific prior written permission from Apple.  Except as

                expressly stated in this notice, no other rights or licenses, express or implied,

                are granted by Apple herein, including but not limited to any patent rights that

                may be infringed by your derivative works or by other works in which the Apple

                Software may be incorporated.

                The Apple Software is provided by Apple on an "AS IS" basis.  APPLE MAKES NO

                WARRANTIES, EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION THE IMPLIED

                WARRANTIES OF NON-INFRINGEMENT, MERCHANTABILITY AND FITNESS FOR A PARTICULAR

                PURPOSE, REGARDING THE APPLE SOFTWARE OR ITS USE AND OPERATION ALONE OR IN

                COMBINATION WITH YOUR PRODUCTS.

                IN NO EVENT SHALL APPLE BE LIABLE FOR ANY SPECIAL, INDIRECT, INCIDENTAL OR

                CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE

                GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)

                ARISING IN ANY WAY OUT OF THE USE, REPRODUCTION, MODIFICATION AND/OR DISTRIBUTION

                OF THE APPLE SOFTWARE, HOWEVER CAUSED AND WHETHER UNDER THEORY OF CONTRACT, TORT

                (INCLUDING NEGLIGENCE), STRICT LIABILITY OR OTHERWISE, EVEN IF APPLE HAS BEEN

                ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

    Change History (most recent first):

*/

#pragma once

/////////////////////////////////////////////////////////////////

// MIB Setup

#include "MoreSetup.h"

// Mac OS Interfaces

#include <MacTypes.h>

#include <OpenTransport.h>

/////////////////////////////////////////////////////////////////////

extern pascal OSStatus InitOTMemoryReserve(ByteCount freeHeapSpaceRequired, ByteCount chunkSize, 

                                           ItemCount minChunks, ItemCount maxChunks,

                                           OTClientContextPtr clientContext);

    // Initialises the module.  Creates an OT memory reserve using 

    // chunkSize chunks.  At least minChunks will be allocated.  At most 

    // maxChunks will be allocated.  There will be at least freeHeapSpaceRequired 

    // bytes left in the heap after the call.

    //

    // There are some simple rules to following for these parameters.

    // 

    // o In order for this module to be effective chunkSize should be

    //   significantly bigger than the largest block you will allocate 

    //   using OTAllocMemFromReserveInContext.

    //

    // o You should set freeHeapSpaceRequired to at least 32 KB, preferably 

    //   a larger value like 64 or 128 KB.  Mac OS does not deal well if 

    //   if you have very little free space in your application partition.

    //

    // o If you intend to use OTAllocMemFromReserveInContext for your 

    //   primary application allocator, (minChunks * chunkSize) + freeHeapSpaceRequired + static allocation size

    //   should be approximately equal to your minimum application partition 

    //   size.

    //

    // o DonÕt pass $FFFFFFFF to maxChunks, even if you want your entire 

    //   application partition (except for freeHeapSpaceRequired bytes) 

    //   to be used for the OT memory reserve.  This will work on current 

    //   systems (because OTAllocMemInContext will be allocating from 

    //   your application partition) but it may cause problems on future 

    //   systems (if OTAllocMemInContext is revised to get memory from 

    //   a read/write file mapping, for example).  Thus is actually the 

    //   case on Mac OS X.  This module does not make a lot of sense on 

    //   Mac OS X, but it will work properly if you pass a reasonable 

    //   value for maxChunks.

    //

    // o ItÕs likely that passing anything other than nil for clientContext 

    //   is a bad idea.  This routine allocates the routine using OTAllocMemInContext, 

    //   passing clientContext as the context parameter.  If you pass a non-nil 

    //   value (not the primary application context), itÕs likely that 

    //   OTAllocMemInContext wonÕt allocate memory from the application heap 

    //   and thus your 

extern pascal void TermOTMemoryReserve(void);

    // Terminates the module.

extern pascal void *OTAllocMemFromReserveInContext(OTByteCount size, OTClientContextPtr clientContext);

    // Allocates memory from OT and, if that fails, returns part of 

    // the memory reserve to OT and tries again.

#if MORE_DEBUG

    extern pascal void OTMemoryReserveTest(void);

        // See comment in implementation part.

#endif