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| /**************************************************************************** |
| * |
| * 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 ); |
| } |