/***
*expand.c - Win32 expand heap routine
*
*       Copyright (c) 1991-1995, Microsoft Corporation. All rights reserved.
*
*Purpose:
*
*Revision History:
*       01-15-92  JCR   Module created.
*       02-04-92  GJF   Replaced windows.h with oscalls.h.
*       05-06-92  DJM   ifndef out of POSIX build.
*       09-23-92  SRW   Change winheap code to call NT directly always
*       10-15-92  SKS   Removed the ill-named HEAP_GROWTH_ALLOWED flag
*               which was causing a bug: _expand was behaving like
*               realloc(), by moving the block when it could not be
*               grown in place.  _expand() must NEVER move the block.
*               Also added a safety check to work around a bug in
*               HeapReAlloc, where it returns success even
*               when it fails to grow the block in place.
*       10-28-92  SRW   Change winheap code to call Heap????Ex calls
*       11-05-92  SKS   Change name of variable "CrtHeap" to "_crtheap"
*       11-07-92  SRW   _NTIDW340 replaced by linkopts\betacmp.c
*       11-16-92  SRW   Heap???Ex functions renamed to Heap???
*       10-21-93  GJF   Replace _CALLTYPE1 with _cdecl. Cleaned up format.
*       04-06-95  GJF   Added support for debug heap.
*       04-29-95  GJF   Copied over from winheap and made conditional on
*               WINHEAP.
*       05-22-95  GJF   Test against _HEAP_MAXREQ before calling API. Also,
*               removed workaround for long-ago NT problem.
*       05-24-95  CFW   Official ANSI C++ new handler added.
*	05-23-95  GJF	Really removed workaround this time...
*
*******************************************************************************/

#ifdef  WINHEAP

#ifndef _POSIX_

#include <cruntime.h>
#include <malloc.h>
#include <winheap.h>
#include <oscalls.h>
#include <dbgint.h>

/***
*void *_expand(void *pblck, size_t newsize) - expand/contract a block of memory
*       in the heap
*
*Purpose:
*       Resizes a block in the heap to newsize bytes. newsize may be either
*       greater (expansion) or less (contraction) than the original size of
*       the block. The block is NOT moved.
*
*       NOTES:
*
*       (1) In this implementation, if the block cannot be grown to the
*       desired size, the resulting block will NOT be grown to the max
*       possible size.  (That is, either it works or it doesn't.)
*
*       (2) Unlike other implementations, you can NOT pass a previously
*       freed block to this routine and expect it to work.
*
*Entry:
*       void *pblck - pointer to block in the heap previously allocated
*                 by a call to malloc(), realloc() or _expand().
*
*       size_t newsize  - requested size for the resized block
*
*Exit:
*       Success:  Pointer to the resized memory block (i.e., pblck)
*       Failure:  NULL
*
*Uses:
*
*Exceptions:
*       If pblck does not point to a valid allocation block in the heap,
*       _expand() will behave unpredictably and probably corrupt the heap.
*
*******************************************************************************/

void * __cdecl _expand_base(
        void * pblock,
        size_t newsize
        )
{
        /* newsize == 0 bumped up to 1 */
        newsize = (newsize ? newsize : 1);

#ifdef HEAPHOOK
        /* call heap hook if installed */
        if (_heaphook) {
            void * retp;
            if ((*_heaphook)(_HEAP_EXPAND, newsize, pblock, (void *)&retp))
                return retp;
        }
#endif /* HEAPHOOK */

        /* validate size */
        if ( newsize > _HEAP_MAXREQ )
            newsize = _HEAP_MAXREQ;

        return (HeapReAlloc( _crtheap,
                 HEAP_REALLOC_IN_PLACE_ONLY,
                 pblock,
                 newsize
                   ));
}

#endif  /* !_POSIX_ */

#endif /* WINHEAP */