memmax.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 59 行

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*                            Open Watcom Project
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#include "dll.h"        // needs to be first
#include "variety.h"
#include <stddef.h>
#include <malloc.h>
#include "heap.h"
#include "heapacc.h"

_WCRTLINK size_t _memmax( void )  /* return size of largest free piece from near heap */
    {
        size_t maxlen, size;
        frlptr pnext;
        mheapptr mhp;

        maxlen = 0;
        _AccessNHeap();
        for( mhp = __nheapbeg; mhp != NULL; mhp = mhp->next ) {
            pnext = mhp->freehead.next;
            while( pnext != (frlptr) &mhp->freehead ) {
                size = ((pnext->len - TAG_SIZE) & ~ROUND_SIZE);
                if( size > maxlen ) maxlen = size;
                pnext = pnext->next;
            }
        }
        _ReleaseNHeap();
        return( maxlen );
    }