/****************************************************************************
*
* 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 <stddef.h>
#include <stdlib.h>
#include <malloc.h>
#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 <wos2.h>
#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
}