/****************************************************************************
*
* 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: Near heap expansion routines.
*
****************************************************************************/
//#include "dll.h" // needs to be first
#include "variety.h"
#include <stddef.h>
#include <malloc.h>
#include "heap.h"
#include "heapacc.h"
#if defined(__DOS_EXT__)
#include "extender.h"
#endif
#if defined(__SMALL_DATA__)
_WCRTLINK void *_expand( void *stg, size_t amount )
{
return( _nexpand( stg, amount ) );
}
#endif
#if defined(__AXP__) || defined(__PPC__)
#define _SEGMENT int
#else
#define _SEGMENT __segment
#endif
int __HeapManager_expand( _SEGMENT seg,
unsigned offset,
size_t req_size,
size_t *growth_size )
{
#if defined(M_I86)
typedef struct freelistp __based(seg) *fptr;
typedef char __based(void) *cptr;
struct miniheapblkp __based(seg) *hblk;
#else
typedef struct freelistp _WCNEAR *fptr;
typedef char _WCNEAR *cptr;
mheapptr hblk;
#endif
fptr p1;
fptr p2;
fptr pnext;
fptr pprev;
size_t new_size;
size_t old_size;
size_t free_size;
/* round (new_size + tag) to multiple of pointer size */
new_size = (req_size + TAG_SIZE + ROUND_SIZE) & ~ROUND_SIZE;
if( new_size < req_size ) new_size = ~0; //go for max
if( new_size < FRL_SIZE ) {
new_size = FRL_SIZE;
}
p1 = (fptr) ((cptr)offset - TAG_SIZE);
old_size = p1->len & ~1;
if( new_size > old_size ) {
/* enlarging the current allocation */
p2 = (fptr) ((cptr)p1 + old_size);
*growth_size = new_size - old_size;
for(;;) {
free_size = p2->len;
if( p2->len == END_TAG ) {
return( __HM_TRYGROW );
} else if( free_size & 1 ) { /* next piece is allocated */
break;
} else {
pnext = p2->next;
pprev = p2->prev;
if( seg == _DGroup() ) { // near heap
for( hblk = __nheapbeg; hblk->next; hblk = hblk->next ) {
if( (fptr)hblk <= (fptr)offset &&
(fptr)((PTR)hblk+hblk->len) > (fptr)offset ) break;
}
}
#if defined(M_I86)
else { // Based heap
hblk = 0;
}
#endif
if( hblk->rover == p2 ) { /* 09-feb-91 */
hblk->rover = p2->prev;
}
if( free_size < *growth_size ||
free_size - *growth_size < FRL_SIZE ) {
/* unlink small free block */
pprev->next = pnext;
pnext->prev = pprev;
p1->len += free_size;
hblk->numfree--;
if( free_size >= *growth_size ) {
return( __HM_SUCCESS );
}
*growth_size -= free_size;
p2 = (fptr) ((cptr)p2 + free_size);
} else {
p2 = (fptr) ((cptr)p2 + *growth_size);
p2->len = free_size - *growth_size;
p2->prev = pprev;
p2->next = pnext;
pprev->next = p2;
pnext->prev = p2;
p1->len += *growth_size;
return( __HM_SUCCESS );
}
}
}
/* no suitable free blocks behind, have to move block */
return( __HM_FAIL );
} else {
/* shrinking the current allocation */
if( old_size - new_size >= FRL_SIZE ) {
/* block big enough to split */
p1->len = new_size | 1;
p1 = (fptr) ((cptr)p1 + new_size);
p1->len = (old_size - new_size) | 1;
if( seg == _DGroup() ) { // near heap
for( hblk = __nheapbeg; hblk->next; hblk = hblk->next ) {
if( (fptr)hblk <= (fptr)offset &&
(fptr)((PTR)hblk+hblk->len) > (fptr)offset ) break;
}
}
#if defined(M_I86)
else // Based heap
hblk = 0;
#endif
/* _bfree will decrement 'numalloc' 08-jul-91 */
hblk->numalloc++;
#if defined(M_I86)
_bfree( seg, (cptr)p1 + TAG_SIZE );
/* free the top portion */
#else
_nfree( (cptr)p1 + TAG_SIZE );
#endif
}
}
return( __HM_SUCCESS );
}
_WCRTLINK void _WCNEAR *_nexpand( void _WCNEAR *stg, size_t req_size )
{
struct {
unsigned expanded : 1;
} flags;
int retval;
size_t growth_size;
flags.expanded = 0;
_AccessNHeap();
for( ;; ) {
retval = __HeapManager_expand( _DGroup(),
(unsigned) stg,
req_size,
&growth_size );
if( retval == __HM_SUCCESS ) {
_ReleaseNHeap();
return( stg );
}
if( retval == __HM_FAIL || !__IsCtsNHeap() ) break;
if( retval == __HM_TRYGROW ) {
if( flags.expanded ) break;
if( __ExpandDGROUP( growth_size ) == 0 ) {
break;
}
flags.expanded = 1;
}
}
_ReleaseNHeap();
return( NULL );
}