kolibrios-fun/programs/develop/open watcom/trunk/clib/heap/nrealloc.c

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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 realloc routines.
*
****************************************************************************/
//#include "dll.h" // needs to be first
#include "variety.h"
#include <stddef.h>
#include <malloc.h>
#include <string.h>
#include "heap.h"
#if defined(__DOS_EXT__)
#include "extender.h"
#endif
#if defined(__SMALL_DATA__)
_WCRTLINK void *realloc( void *stg, size_t amount )
{
return( _nrealloc( stg, amount ) );
}
#endif
#pragma intrinsic(memcpy)
_WCRTLINK void _WCNEAR *_nrealloc( void _WCI86NEAR *stg, size_t req_size )
{
void _WCNEAR *p;
size_t old_size;
if( stg == NULL ) {
return( _nmalloc( req_size ) );
}
if( req_size == 0 ) {
_nfree( stg );
return( (void _WCNEAR *) NULL );
}
old_size = _nmsize( stg );
p = _nexpand( stg, req_size ); /* try to expand it in place */
if( p == NULL ) { /* if couldn't be expanded in place */
#if defined(__DOS_EXT__)
if( _IsRational() ) {
frlptr flp, newflp;
flp = (frlptr) ((PTR)stg - TAG_SIZE);
newflp = __ReAllocDPMIBlock( flp, req_size + TAG_SIZE );
if( newflp ) {
return( (void _WCNEAR *)((PTR)newflp + TAG_SIZE) );
}
}
#endif
p = _nmalloc( req_size ); /* - allocate a new block */
if( p != NULL ) { /* - if we got one */
memcpy( p, stg, old_size ); /* copy it */
_nfree( stg ); /* and free old one */
} else {
_nexpand( stg, old_size ); /* reset back to old size */
}
}
return( p );
}