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/***
*heapwalk.c - walk the heap
*
* Copyright (c) 1989-1991, Microsoft Corporation. All rights reserved.
*
*Purpose:
* Defines the _heapwalk() function
*
*Revision History:
* 07-05-89 JCR Module created.
* 11-13-89 GJF Added MTHREAD support, also fixed copyright.
* 11-14-89 JCR Fixed bug -- returned address was off by HDRSIZE
* 12-18-89 GJF Removed DEBUG286 stuff, also some tuning, cleaned up
* format a bit, changed header file name to heap.h, added
* explicit _cdecl to function definition
* 12-20-89 GJF Removed references to plastdesc
* 03-11-90 GJF Replaced _cdecl with _CALLTYPE1, added #include
* <cruntime.h> and removed #include <register.h>.
* 09-28-90 GJF New-style function declarator.
*
*******************************************************************************/
#include <cruntime.h>
#include <heap.h>
#include <malloc.h>
#include <os2dll.h>
#include <stddef.h>
/***
*int _heapwalk() - Walk the heap
*
*Purpose:
* Walk the heap returning information on one entry at a time.
*
*Entry:
* struct _heapinfo {
* int * _pentry; heap entry pointer
* size_t size; size of heap entry
* int _useflag; free/inuse flag
* } *entry;
*
*Exit:
* Returns one of the following values:
*
* _HEAPOK - completed okay
* _HEAPEMPTY - heap not initialized
* _HEAPBADPTR - _pentry pointer is bogus
* _HEAPBADBEGIN - can't find initial header info
* _HEAPBADNODE - malformed node somewhere
* _HEAPEND - end of heap successfully reached
*
*Uses:
*
*Exceptions:
*
*******************************************************************************/
int _CALLTYPE1 _heapwalk (
struct _heapinfo *_entry
)
{
REG1 _PBLKDESC pdesc;
_PBLKDESC polddesc;
int retval = _HEAPOK;
/*
* Lock the heap
*/
_mlock(_HEAP_LOCK);
/*
* Quick header check
*/
if ( (_heap_desc.pfirstdesc == NULL) ||
(_heap_desc.proverdesc == NULL) ||
(_heap_desc.sentinel.pnextdesc != NULL) ) {
retval = _HEAPBADBEGIN;
goto done;
}
/*
* Check for an empty heap
*/
if ( _heap_desc.pfirstdesc == &_heap_desc.sentinel ) {
retval = _HEAPEMPTY;
goto done;
}
/*
* If _pentry is NULL, return info about the first entry.
* Else, get info about the next entry in the heap.
*/
if ( _entry->_pentry == NULL ) {
pdesc = _heap_desc.pfirstdesc;
}
else {
/*
* Find the entry we gave to the user last time around
*/
if ( _heap_findaddr( (void *)((char *)(_entry->_pentry) -
_HDRSIZE), &polddesc) != _HEAPFIND_EXACT ) {
retval = _HEAPBADPTR;
goto done;
}
pdesc = polddesc->pnextdesc;
} /* else */
/*
* pdesc = entry to return info about
*/
/*
* Skip over dummy entries
*/
while ( _IS_DUMMY(pdesc) )
pdesc = pdesc->pnextdesc;
/*
* See if we're at the end of the heap
*/
if ( pdesc == &_heap_desc.sentinel ) {
retval = _HEAPEND;
goto done;
}
/*
* Check back pointer (note that pdesc cannot point to a dummy
* descriptor since we have skipped over them)
*/
if (!_CHECK_PDESC(pdesc)) {
retval = _HEAPBADPTR;
goto done;
}
/*
* Return info on the next block
*/
_entry->_pentry = ( (void *)((char *)_ADDRESS(pdesc) + _HDRSIZE) );
_entry->_size = _BLKSIZE(pdesc);
_entry->_useflag = ( _IS_INUSE(pdesc) ? _USEDENTRY : _FREEENTRY );
/*
* Common return
*/
done:
/*
* Release the heap lock
*/
_munlock(_HEAP_LOCK);
return(retval);
}
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