int __cdecl _heap_addblock (
void * block,
size_t size
)
{
_PBLKDESC pdesc;
REG1 _PBLKDESC pnewdesc;
_PBLKDESC pdescs[4] = { NULL, NULL, NULL, NULL };
_PBLKDESC *ppdesc = pdescs;
size_t lastsize;
int find;
/*
* Make sure we enough empty descriptors to do the job! Do it here
* and now because recovering from an out-of-descriptors condition
* is too dicey later on.
*/
if ( ((pdescs[0] = __getempty()) == NULL) ||
((pdescs[1] = __getempty()) == NULL) ||
((pdescs[2] = __getempty()) == NULL) )
{
goto error;
}
/*
* Find where the address fits into the heap.
*/
find = _heap_findaddr(block, &pdesc);
/*
* Fill in the new heap descriptor.
* (1) If the new address is an exact fit, use the dummy
* descriptor that already exists for it.
* (2) If the address is NOT in the heap, allocate a new one.
*/
if ( find == _HEAPFIND_EXACT ) {
if ( !(_IS_DUMMY(pdesc)) )
goto error;
pnewdesc = pdesc;
}
else {
pnewdesc = *(ppdesc++);
}
pnewdesc->pblock = block; /* pointer to block */
_SET_FREE(pnewdesc); /* set me free (why don't ya, babe) */
*(_PBLKDESC*)block = pnewdesc; /* init back pointer */
/*
* Put the block in the heap
* find = result of _heap_findaddr() call
* pnewdesc = points to desc to be inserted
* pdesc = filled in by _heap_findaddr() call as appropriate
*/
switch (find) {
case(_HEAPFIND_EMPTY):
/*
* No memory in heap yet
*/
_heap_desc.sentinel.pblock = (char *) block + size;
_before(pnewdesc, size, &_heap_desc.sentinel,
&ppdesc);
_heap_desc.pfirstdesc = _heap_desc.proverdesc =
pnewdesc;
break;
case(_HEAPFIND_BEFORE):
/*
* New block is before the heap
*/
_before(pnewdesc, size, _heap_desc.pfirstdesc,
&ppdesc);
_heap_desc.pfirstdesc = pnewdesc;
break;
case(_HEAPFIND_AFTER):
/*
* New block is after the heap
*
* Find the current last block in the heap
*/
if ( _heap_findaddr((void *)((char *)
(_heap_desc.sentinel.pblock) - 1), &pdesc) !=
_HEAPFIND_WITHIN )
_heap_abort();
lastsize = _MEMSIZE(pdesc);
/*
* Start insertion by placing new block immediately
* in front of the sentinel
*/
_heap_desc.sentinel.pblock = (char *) block + size;
pnewdesc->pnextdesc = &_heap_desc.sentinel;
/*
* Finish insertion by placing new block after the
* old last block (with a possible intervening dummy
* block being created)
*/
_before(pdesc, lastsize, pnewdesc,
&ppdesc);
break;
case(_HEAPFIND_EXACT):
/*
* Block is already in the heap (and we've checked
* that it was a "dummy" before this call).
*
* [NOTES: (1) pnewdesc and pdesc are the same,
* (2) pnewdesc is already linked to the previous
* heap entry, (3) pdesc->pnextdesc is still valid!
* (4) Also, if pdesc->pnextdesc is the sentinel,
* then simply update the sentinel size (calling
* before will cause an error if the previous last
* block was bigger than the current one!).
* (see code at top of this routine).]
*/
if (pdesc->pnextdesc == &_heap_desc.sentinel)
_heap_desc.sentinel.pblock =
(char *) _ADDRESS(pdesc) + size;
else
_before(pnewdesc, size, pdesc->pnextdesc,
&ppdesc);
break;
default:
/*
* New block is within heap
*/
if (!(_IS_DUMMY(pdesc)))
goto error;
/*
* If the last block in the heap is a dummy region
* and a new region is allocated which lies within
* that region, we need to update sentinel.pblock.
*/
if (pdesc->pnextdesc == &_heap_desc.sentinel)
{
void * newend = (char *) _ADDRESS(pnewdesc) + size;
if (_heap_desc.sentinel.pblock < newend)
_heap_desc.sentinel.pblock = newend;
}
_before(pnewdesc, size, pdesc->pnextdesc,
&ppdesc);
_before(pdesc, _MEMSIZE(pdesc), pnewdesc,
&ppdesc);
break;
}
/*
* Update rover, if appropriate
*/
if ( (block < _ADDRESS(_heap_desc.proverdesc)) &&
(_BLKSIZE(pnewdesc) >= _heap_resetsize) )
_heap_desc.proverdesc = pnewdesc;
/*
* Good return
*/
/* good: unreferenced label to be removed */
return(0);
/*
* Error return
*/
error:
while ( *ppdesc != NULL ) {
_PUTEMPTY(*ppdesc);
ppdesc++;
}
return(-1);
}
int __cdecl _heapmin(void)
{
REG1 int index;
_PBLKDESC pdesc;
REG2 _PBLKDESC pdesc2;
void * regend;
int region_min_count = 0;
#if defined(_M_MPPC) || defined(_M_M68K)
struct _heap_region_ *pHeapRegions;
#endif
/*
* Lock the heap
*/
_mlock(_HEAP_LOCK);
/*
* Coalesce the heap (should return NULL)
*/
if ( _heap_search((unsigned)_HEAP_COALESCE) != NULL )
_heap_abort();
/*
* Loop through the region descriptor table freeing as much
* memory to the OS as possible.
*/
#if defined(_M_MPPC) || defined(_M_M68K)
for ( index=0 ; index < _heap_region_table_cur ; index++ ) {
pHeapRegions = (struct _heap_region_ *)(*hHeapRegions);
if ( (pHeapRegions + index)->_regbase == NULL )
continue; /* region entry is empty */
/*
* Get the entry that contains the last address of
* the region (allocated so far, that is).
*/
regend = (char *) ( (pHeapRegions + index)->_regbase) +
(pHeapRegions + index)->_currsize - 1;
#else /* !defined(_M_MPPC) && !defined(_M_M68K) */
for ( index=0 ; index < _HEAP_REGIONMAX ; index++ ) {
if ( _heap_regions[index]._regbase == NULL )
continue; /* region entry is empty */
/*
* Get the entry that contains the last address of
* the region (allocated so far, that is).
*/
regend = (char *) _heap_regions[index]._regbase +
_heap_regions[index]._currsize - 1;
#endif /* defined(_M_MPPC) || defined(_M_M68K) */
if ( _heap_findaddr(regend, &pdesc) != _HEAPFIND_WITHIN )
_heap_abort(); /* last address not within a block */
/*
* See if the containing block is free
*/
if ( !(_IS_FREE(pdesc)) )
continue; /* block is not free */
/*
* Region ends with a free block, go free as much mem
* as possible.
*/
region_min_count += _heapmin_region(index, regend, pdesc);
} /* region loop */
/*
* By minimizing the heap, we've likely invalidated the rover and
* may have produced contiguous dummy blocks so:
*
* (1) reset the rover
* (2) coalesce contiguous dummy blocks
*/
if ( region_min_count ) {
/*
* Set proverdesc to pfirstdesc
*/
_heap_desc.proverdesc = _heap_desc.pfirstdesc;
for ( pdesc = _heap_desc.pfirstdesc ; pdesc !=
&_heap_desc.sentinel ; pdesc = pdesc->pnextdesc ) {
/*
* Check and remove consecutive dummy blocks
*/
if ( _IS_DUMMY(pdesc) ) {
for ( pdesc2 = pdesc->pnextdesc ;
_IS_DUMMY(pdesc2) ;
pdesc2 = pdesc->pnextdesc ) {
/*
* coalesce the dummy blocks
*/
pdesc->pnextdesc = pdesc2->pnextdesc;
_PUTEMPTY(pdesc2);
} /* dummy loop */
} /* if */
} /* heap loop */
} /* region_min_count */
/*
* Good return
*/
/* goodrtn: unreferenced label to be removed */
/*
* Release the heap lock
*/
_munlock(_HEAP_LOCK);
return(0);
}
/***
*_heapmin_region() - Minimize a region
*
*Purpose:
* Free as much of a region back to the OS as possible.
*
*Entry:
* int index = index of the region in the region table
* void * regend = last valid address in region
* pdesc = pointer to the last block of memory in the region
* (it has already been determined that this block is free)
*
*Exit:
* int 1 = minimized region
* 0 = no change to region
*
*Exceptions:
*
*******************************************************************************/
static int __cdecl _heapmin_region (
int index,
void * regend,
REG1 _PBLKDESC pdesc
)
{
unsigned size;
REG2 _PBLKDESC pnew;
#if defined(_M_MPPC) || defined(_M_M68K)
struct _heap_region_ *pHeapRegions;
#endif
/*
* Init some variables
*
* regend = 1st address AFTER region
* size = amount of free memory at end of current region
*/
regend = (char *) regend + 1; /* "regend++" give compiler error... */
size = ((char *)regend - (char *)_ADDRESS(pdesc));
/*
* See if there's enough free memory to release to the OS.
* (NOTE: Need more than a page since we may need a back pointer.)
*/
if ( size <= _PAGESIZE_ )
return(0); /* 0 = no change to region */
/*
* We're going to free some memory to the OS. See if the
* free block crosses the end of the region and, if so,
* split up the block appropriately.
*/
if ( (_MEMSIZE(pdesc) - size) != 0 ) {
/*
* The free block spans the end of the region.
* Divide it up.
*/
/*
* Get an empty descriptor
*/
if ( (pnew = __getempty()) == NULL )
return(0);
pnew->pblock = regend; /* init block pointer */
* (_PBLKDESC*)regend = pnew; /* init back pointer */
_SET_FREE(pnew); /* set the block free */
pnew->pnextdesc = pdesc->pnextdesc; /* link it in */
pdesc->pnextdesc = pnew;
}
/*
* At this point, we have a free block of memory that goes
* up to (but not exceeding) the end of the region.
*
* pdesc = descriptor of the last free block in region
* size = amount of free mem at end of region (i.e., _MEMSIZE(pdesc))
* regend = 1st address AFTER end of region
*/
/*
* See if we should return the whole region of only part of it.
*/
#if defined(_M_MPPC) || defined(_M_M68K)
pHeapRegions = (struct _heap_region_ *)(*hHeapRegions);
if ( _ADDRESS(pdesc) == (pHeapRegions + index)->_regbase ) {
#else
if ( _ADDRESS(pdesc) == _heap_regions[index]._regbase ) {
#endif
/*
* Whole region is free, return it to OS
*/
_heap_free_region(index);
/*
* Put a dummy block in the heap to hold space for
* the memory we just freed up.
*/
_SET_DUMMY(pdesc);
}
else {
/*
* Whole region is NOT free, return part of it to OS
*/
#if !defined(_M_MPPC) && !defined(_M_M68K)
_free_partial_region(pdesc, size, index);
#endif
}
/*
* Exit paths
*/
return(1); /* 1 = minimized region */
}
/***
*_free_partial_region() - Free part of a region to the OS
*
*Purpose:
* Free a portion of a region to the OS
*
*Entry:
* pdesc = descriptor of last free block in region
* size = amount of free mem at end of region (i.e., _MEMSIZE(pdesc))
* index = index of region
*
*Exit:
*
*Exceptions:
*
*******************************************************************************/
static void __cdecl _free_partial_region (
REG1 _PBLKDESC pdesc,
unsigned size,
int index
)
{
unsigned left;
void * base;
REG2 _PBLKDESC pnew;
#if defined(_M_MPPC) || defined(_M_M68K)
struct _heap_region_ *pHeapRegions;
#endif
/*
* Init a few variables.
*/
left = (size & (_PAGESIZE_-1));
base = (char *)_ADDRESS(pdesc);
/*
* We return memory to the OS in page multiples. If the
* free block is not page aligned, we'll insert a new free block
* to fill in the difference.
*/
if ( left != 0 ) {
/*
* The block is not a multiple of pages so we need
* to adjust variables accordingly.
*/
size -= left;
base = (char *)base + left;
}
/*
* Return the free pages to the OS.
*/
#if defined(_M_MPPC) || defined(_M_M68K)
if (base)
{
DisposePtr(base);
}
/*
* Adjust the region table entry
*/
pHeapRegions = (struct _heap_region_ *)(*hHeapRegions);
(pHeapRegions + index)->_currsize -= size;
#else /* !defined(_M_MPPC) && !defined(_M_M68K) */
if (!VirtualFree(base, size, MEM_DECOMMIT))
_heap_abort();
/*
* Adjust the region table entry
*/
_heap_regions[index]._currsize -= size;
#endif /* defined(_M_MPPC) || defined(_M_M68K) */
/*
* Adjust the heap according to whether we released the whole
* free block or not. (Don't worry about consecutive dummies,
* we'll coalesce them later.)
*
* base = address of block we just gave back to OS
* size = size of block we gave back to OS
* left = size of block we did NOT give back to OS
*/
if ( left == 0 ) {
/*
* The free block was released to the OS in its
* entirety. Make the free block a dummy place holder.
*/
_SET_DUMMY(pdesc);
}
else {
/*
* Did NOT release the whole free block to the OS.
* There's a block of free memory we want to leave
* in the heap. Insert a dummy entry after it.
*/
if ( (pnew = __getempty()) == NULL )
_heap_abort();
pnew->pblock = (char *)base;
_SET_DUMMY(pnew);
pnew->pnextdesc = pdesc->pnextdesc;
pdesc->pnextdesc = pnew;
}
}
