forked from KolibriOS/kolibrios
206 lines
6.9 KiB
C
206 lines
6.9 KiB
C
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/****************************************************************************
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*
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* Open Watcom Project
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*
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* Portions Copyright (c) 1983-2002 Sybase, Inc. All Rights Reserved.
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*
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* ========================================================================
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*
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* This file contains Original Code and/or Modifications of Original
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* Code as defined in and that are subject to the Sybase Open Watcom
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* Public License version 1.0 (the 'License'). You may not use this file
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* except in compliance with the License. BY USING THIS FILE YOU AGREE TO
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* ALL TERMS AND CONDITIONS OF THE LICENSE. A copy of the License is
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* provided with the Original Code and Modifications, and is also
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* available at www.sybase.com/developer/opensource.
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*
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* The Original Code and all software distributed under the License are
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* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
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* EXPRESS OR IMPLIED, AND SYBASE AND ALL CONTRIBUTORS HEREBY DISCLAIM
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* ALL SUCH WARRANTIES, INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF
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* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR
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* NON-INFRINGEMENT. Please see the License for the specific language
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* governing rights and limitations under the License.
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*
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* ========================================================================
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*
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* Description: Near heap expansion routines.
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*
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****************************************************************************/
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//#include "dll.h" // needs to be first
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#include "variety.h"
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#include <stddef.h>
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#include <malloc.h>
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#include "heap.h"
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#include "heapacc.h"
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#if defined(__DOS_EXT__)
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#include "extender.h"
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#endif
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#if defined(__SMALL_DATA__)
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_WCRTLINK void *_expand( void *stg, size_t amount )
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{
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return( _nexpand( stg, amount ) );
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}
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#endif
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#if defined(__AXP__) || defined(__PPC__)
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#define _SEGMENT int
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#else
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#define _SEGMENT __segment
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#endif
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int __HeapManager_expand( _SEGMENT seg,
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unsigned offset,
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size_t req_size,
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size_t *growth_size )
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{
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#if defined(M_I86)
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typedef struct freelistp __based(seg) *fptr;
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typedef char __based(void) *cptr;
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struct miniheapblkp __based(seg) *hblk;
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#else
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typedef struct freelistp _WCNEAR *fptr;
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typedef char _WCNEAR *cptr;
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mheapptr hblk;
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#endif
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fptr p1;
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fptr p2;
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fptr pnext;
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fptr pprev;
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size_t new_size;
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size_t old_size;
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size_t free_size;
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/* round (new_size + tag) to multiple of pointer size */
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new_size = (req_size + TAG_SIZE + ROUND_SIZE) & ~ROUND_SIZE;
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if( new_size < req_size ) new_size = ~0; //go for max
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if( new_size < FRL_SIZE ) {
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new_size = FRL_SIZE;
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}
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p1 = (fptr) ((cptr)offset - TAG_SIZE);
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old_size = p1->len & ~1;
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if( new_size > old_size ) {
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/* enlarging the current allocation */
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p2 = (fptr) ((cptr)p1 + old_size);
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*growth_size = new_size - old_size;
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for(;;) {
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free_size = p2->len;
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if( p2->len == END_TAG ) {
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return( __HM_TRYGROW );
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} else if( free_size & 1 ) { /* next piece is allocated */
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break;
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} else {
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pnext = p2->next;
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pprev = p2->prev;
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if( seg == _DGroup() ) { // near heap
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for( hblk = __nheapbeg; hblk->next; hblk = hblk->next ) {
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if( (fptr)hblk <= (fptr)offset &&
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(fptr)((PTR)hblk+hblk->len) > (fptr)offset ) break;
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}
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}
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#if defined(M_I86)
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else { // Based heap
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hblk = 0;
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}
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#endif
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if( hblk->rover == p2 ) { /* 09-feb-91 */
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hblk->rover = p2->prev;
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}
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if( free_size < *growth_size ||
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free_size - *growth_size < FRL_SIZE ) {
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/* unlink small free block */
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pprev->next = pnext;
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pnext->prev = pprev;
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p1->len += free_size;
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hblk->numfree--;
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if( free_size >= *growth_size ) {
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return( __HM_SUCCESS );
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}
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*growth_size -= free_size;
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p2 = (fptr) ((cptr)p2 + free_size);
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} else {
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p2 = (fptr) ((cptr)p2 + *growth_size);
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p2->len = free_size - *growth_size;
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p2->prev = pprev;
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p2->next = pnext;
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pprev->next = p2;
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pnext->prev = p2;
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p1->len += *growth_size;
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return( __HM_SUCCESS );
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}
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}
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}
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/* no suitable free blocks behind, have to move block */
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return( __HM_FAIL );
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} else {
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/* shrinking the current allocation */
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if( old_size - new_size >= FRL_SIZE ) {
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/* block big enough to split */
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p1->len = new_size | 1;
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p1 = (fptr) ((cptr)p1 + new_size);
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p1->len = (old_size - new_size) | 1;
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if( seg == _DGroup() ) { // near heap
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for( hblk = __nheapbeg; hblk->next; hblk = hblk->next ) {
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if( (fptr)hblk <= (fptr)offset &&
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(fptr)((PTR)hblk+hblk->len) > (fptr)offset ) break;
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}
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}
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#if defined(M_I86)
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else // Based heap
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hblk = 0;
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#endif
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/* _bfree will decrement 'numalloc' 08-jul-91 */
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hblk->numalloc++;
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#if defined(M_I86)
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_bfree( seg, (cptr)p1 + TAG_SIZE );
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/* free the top portion */
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#else
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_nfree( (cptr)p1 + TAG_SIZE );
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#endif
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}
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}
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return( __HM_SUCCESS );
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}
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_WCRTLINK void _WCNEAR *_nexpand( void _WCNEAR *stg, size_t req_size )
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{
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struct {
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unsigned expanded : 1;
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} flags;
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int retval;
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size_t growth_size;
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flags.expanded = 0;
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_AccessNHeap();
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for( ;; ) {
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retval = __HeapManager_expand( _DGroup(),
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(unsigned) stg,
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req_size,
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&growth_size );
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if( retval == __HM_SUCCESS ) {
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_ReleaseNHeap();
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return( stg );
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}
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if( retval == __HM_FAIL || !__IsCtsNHeap() ) break;
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if( retval == __HM_TRYGROW ) {
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if( flags.expanded ) break;
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if( __ExpandDGROUP( growth_size ) == 0 ) {
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break;
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}
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flags.expanded = 1;
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}
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}
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_ReleaseNHeap();
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return( NULL );
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}
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