bexpand.c

来自「开放源码的编译器open watcom 1.6.0版的源代码」· C语言 代码 · 共 68 行

/****************************************************************************
*
*                            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
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*    except in compliance with the License. BY USING THIS FILE YOU AGREE TO
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*    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
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* Description:  WHEN YOU FIGURE OUT WHAT THIS FILE DOES, PLEASE
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****************************************************************************/


#include "dll.h"        // needs to be first
#include "variety.h"
#include <malloc.h>
#include "heap.h"
#include "heapacc.h"

_WCRTLINK void __based(void) *_bexpand( __segment seg,
                              void __based(void) *mem,
                              size_t req_size )
    {
        struct {
            unsigned expanded : 1;
        } flags;
        int retval;
        size_t growth_size;

        flags.expanded = 0;
        _AccessFHeap();
        for( ;; ) {
            retval = __HeapManager_expand( seg, (unsigned)mem,
                                           req_size, &growth_size );
            if( retval == __HM_SUCCESS ) {
                _ReleaseFHeap();
                return( mem );
            }
            if( retval == __HM_FAIL ) break;
            if( retval == __HM_TRYGROW ) {
                if( flags.expanded ) break;
                if( __GrowSeg( seg, growth_size ) == 0 ) break;
                flags.expanded = 1;
            }
        }
        _ReleaseFHeap();
        return( _NULLOFF );
    }