Subversion Repositories Kolibri OS

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

*

*                            Open Watcom Project

*

*    Portions Copyright (c) 1983-2002 Sybase, Inc. All Rights Reserved.

*

*  ========================================================================

*

*    This file contains Original Code and/or Modifications of Original

*    Code as defined in and that are subject to the Sybase Open Watcom

*    Public License version 1.0 (the 'License'). You may not use this file

*    except in compliance with the License. BY USING THIS FILE YOU AGREE TO

*    ALL TERMS AND CONDITIONS OF THE LICENSE. A copy of the License is

*    provided with the Original Code and Modifications, and is also

*    available at www.sybase.com/developer/opensource.

*

*    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 SYBASE AND ALL CONTRIBUTORS HEREBY DISCLAIM

*    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.

*

*  ========================================================================

*

* Description:  Implementation of near _heapmin() and _nheapmin().

*

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

#include "variety.h"

#include 

#include 

#include 

#include "heap.h"

#include "heapacc.h"

#if defined(__DOS_EXT__)

// #include "extender.h"

#endif

#if defined(__WINDOWS_286__) || defined(__NT__)

 #include "kolibri.h"

#endif

#if defined(__OS2__)

// #include 

#endif

#if defined(__WINDOWS_386__)

// extern int __pascal DPMIFree(unsigned long);   // windows extender function

#endif

#if defined(__CALL21__)

// #include "tinyio.h"

#endif

#if defined(__SMALL_DATA__)

_WCRTLINK int _heapshrink( void )

{

    return( _nheapshrink() );

}

_WCRTLINK int _heapmin( void )

{

    return( _nheapshrink() );

}

#endif

_WCRTLINK int _nheapmin( void )

{

    return( _nheapshrink() );

}

#if defined(__WARP__)        || \

    defined(__WINDOWS_286__) || \

    defined(__WINDOWS_386__) || \

    defined(__NT__)          || \

    defined(__CALL21__)

static void __ReleaseMiniHeap( mheapptr mhp )

{

    mheapptr pprev;

    mheapptr pnext;

    pprev = mhp->prev;

    pnext = mhp->next;

    if( user_free( mhp ) == 1 ) {

        if( pprev == NULL ) {

            __nheapbeg = pnext;

        } else {

            pprev->next = pnext;

        }

        if( pnext != NULL )  pnext->prev = pprev;

    } //else: do not unlink if the memory cannot be freed successfully

}

#endif

_WCRTLINK int _nheapshrink( void )

{

    mheapptr mhp;

#if !defined(__WARP__)        && \

    !defined(__WINDOWS_286__) && \

    !defined(__WINDOWS_386__) && \

    !defined(__NT__)          && \

    !defined(__CALL21__)

    // Shrink by adjusting _curbrk

    frlptr last_free;

    frlptr end_tag;

    unsigned new_brk;

    _AccessNHeap();

    #if defined(__DOS_EXT__)

    if( !_IsRationalZeroBase() && !_IsCodeBuilder() ) {

    #endif

        if( __nheapbeg == NULL ) {

            _ReleaseNHeap();

            return( 0 ); // No near heap, can't shrink

        }

        /* Goto the end of miniheaplist (if there's more than 1 blk) */

        for( mhp = __nheapbeg; mhp->next; mhp = mhp->next );

        /* check that last free block is at end of heap */

        last_free = mhp->freehead.prev;

        end_tag = (frlptr) ( (PTR)last_free + last_free->len );

        if( end_tag->len != END_TAG ) {

            _ReleaseNHeap();

            return( 0 );

        }

        if( end_tag != (frlptr) ((PTR)mhp + mhp->len ) ) {

            _ReleaseNHeap();

            return( 0 );

        }

        #if defined(__DOS_EXT__)

        // only shrink if we can shave off at least 4k

        if( last_free->len < 0x1000 ) {

            _ReleaseNHeap();

            return( 0 );

        }

        #else

        if( last_free->len <= sizeof( frl ) ) {

            _ReleaseNHeap();

            return( 0 );

        }

        #endif

        /* make sure there hasn't been an external change in _curbrk */

        if( sbrk( 0 ) != &(end_tag->prev) ) {

            _ReleaseNHeap();

            return( 0 );

        }

        /* calculate adjustment factor */

        if( mhp->len-last_free->len > sizeof( struct miniheapblkp ) ) {

            // this miniheapblk is still being used

            #if defined(__DOS_EXT__)

                frlptr new_last_free;

                new_last_free = (frlptr)((((unsigned)last_free + 0xfff) & ~0xfff) - TAG_SIZE);

                if( new_last_free == last_free ) {

            #endif

                    // remove entire entry

                    mhp->len -= last_free->len;

                    --mhp->numfree;

                    // Relink the freelist entries, and update the rover

                    mhp->freehead.prev = last_free->prev;

                    last_free->prev->next = &mhp->freehead;

                    if( mhp->rover == last_free ) mhp->rover = last_free->prev;

            #if defined(__DOS_EXT__)

                } else {

                    // just shrink the last free entry

                    mhp->len -= last_free->len;

                    last_free->len = (PTR)new_last_free - (PTR)last_free;

                    mhp->len += last_free->len;

                    last_free = new_last_free;

                }

            #endif

            last_free->len = END_TAG;

            new_brk = (unsigned) ((PTR)last_free + TAG_SIZE );

        } else {

            // we can remove this miniheapblk

            if( mhp->prev ) { // Not the first miniheapblk

                mhp->prev->next = NULL;

                new_brk = (unsigned)mhp;//->prev + (unsigned)mhp->prev->len;

            } else { // Is the first miniheapblk

                new_brk = (unsigned)__nheapbeg;

                __nheapbeg = NULL;

            }

            // Update rover info

            if( __MiniHeapRover == mhp ) {

                __MiniHeapRover = __nheapbeg;

                __LargestSizeB4MiniHeapRover = 0;

            }

        }

        if( __brk( new_brk ) == (void _WCNEAR *) -1 ) {

            _ReleaseNHeap();

            return( -1 );

        }

        _ReleaseNHeap();

        return( 0 );

    #if defined(__DOS_EXT__)

    }

    __FreeDPMIBlocks(); // For RSI/zero-base and Intel CB

    _ReleaseNHeap();

    return( 0 );

    #endif

#else

    // Shrink by releasing mini-heaps

    {

        mheapptr pnext;

        _AccessNHeap();

        for( mhp = __nheapbeg; mhp; mhp = pnext ) {

            pnext = mhp->next;

            if( mhp->len - sizeof(struct miniheapblkp) ==

                (mhp->freehead.prev)->len ) __ReleaseMiniHeap( mhp );

        }

        _ReleaseNHeap();

        return( 0 );

    }

#endif

}