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/***
*free.c - free an entry in the heap
*
* Copyright (c) 1989-1991, Microsoft Corporation. All rights reserved.
*
*Purpose:
* Defines the following functions:
* free() - free a memory block in the heap
* _free_lk() - non-locking from of free() (multi-thread only)
*
*Revision History:
* 06-30-89 JCR Module created
* 07-07-89 GJF Fixed test for resetting proverdesc
* 11-10-89 GJF Added MTHREAD support. Also, a little cleanup.
* 12-18-89 GJF Change header file name to heap.h, added register
* declarations and added explicit _cdecl to function
* definitions
* 03-09-90 GJF Replaced _cdecl with _CALLTYPE1, added #include
* <cruntime.h> and removed #include <register.h>.
* 09-27-90 GJF New-style function declarators. Also, rewrote expr.
* so that a cast was not used as an lvalue.
* 03-05-91 GJF Changed strategy for rover - old version available
* by #define-ing _OLDROVER_.
* 04-08-91 GJF Temporary hack for Win32/DOS folks - special version
* of free that just calls HeapFree. Change conditioned
* on _WIN32DOS_.
*
*******************************************************************************/
#ifndef _WIN32DOS_
#include <cruntime.h>
#include <heap.h>
#include <malloc.h>
#include <os2dll.h>
#include <stdlib.h>
/***
*void free(pblock) - free a block in the heap
*
*Purpose:
* Free a memory block in the heap.
*
* Special Notes For Multi-thread: The non-multi-thread version is renamed
* to _free_lk(). The multi-thread free() simply locks the heap, calls
* _free_lk(), then unlocks the heap and returns.
*
*Entry:
* void *pblock - pointer to a memory block in the heap
*
*Return:
* <void>
*
*******************************************************************************/
#ifdef MTHREAD
void _CALLTYPE1 free (
void *pblck
)
{
/* lock the heap
*/
_mlock(_HEAP_LOCK);
/* free the block
*/
_free_lk(pblck);
/* unlock the heap
*/
_munlock(_HEAP_LOCK);
}
/***
*void _free_lk(pblock) - non-locking form of free
*
*Purpose:
* Same as free() except that no locking is performed
*
*Entry:
* See free
*
*Return:
*
*******************************************************************************/
void _CALLTYPE1 _free_lk (
#else /* ndef MTHREAD */
void _CALLTYPE1 free (
#endif /* MTHREAD */
REG1 void *pblck
)
{
REG2 _PBLKDESC pdesc;
/*
* If the pointer is NULL, just return [ANSI].
*/
if (pblck == NULL)
return;
/*
* Point to block header and get the pointer back to the heap desc.
*/
pblck = (char *)pblck - _HDRSIZE;
pdesc = *(_PBLKDESC*)pblck;
/*
* Validate the back pointer.
*/
if (_ADDRESS(pdesc) != pblck)
_heap_abort();
/*
* Pointer is ok. Mark block free.
*/
_SET_FREE(pdesc);
/*
* Back up rover pointer, if appropriate.
*/
#ifdef _OLDROVER_
if (_heap_desc.proverdesc->pblock > pdesc->pblock)
_heap_desc.proverdesc = pdesc;
#else /* ndef _OLDROVER_ */
if ( (_heap_resetsize != 0xffffffff) &&
(_heap_desc.proverdesc->pblock > pdesc->pblock) &&
(_BLKSIZE(pdesc) >= _heap_resetsize) )
_heap_desc.proverdesc = pdesc;
#endif /* _OLDROVER_ */
}
#else /* _WIN32DOS_ */
/*
* TEMPORARY HACK! THE CODE BELOW IS INTENDED TO ALLOW LIMITED USE OF THE
* C RUNTIME ON WIN32/DOS. IT WILL BE DELETED AS SOON AS THEY IMPLEMENT
* VirtualAlloc()!
*/
#include <cruntime.h>
#include <oscalls.h>
#include <malloc.h>
extern HANDLE _HeapHandle;
void _CALLTYPE1 free (
void *pblck
)
{
HeapFree(_HeapHandle, pblck);
return;
}
#endif /* _WIN32DOS_ */
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