Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!swrinde!cs.utexas.edu!uunet!sdl.mdcbbs.com!alanb
From: alanb@sdl.mdcbbs.com
Newsgroups: comp.lang.c++
Subject: Re: proposal for new/delete extension
Message-ID: <1991Jun26.103505.1@sdl.mdcbbs.com>
Date: 26 Jun 91 09:35:05 GMT
References: <19215@prometheus.megatest.UUCP>
Organization: Shape Data Ltd. (McDonnell Douglas M&E, Cambridge UK)
Lines: 33
Nntp-Posting-Host: shapeg
Nntp-Posting-User: alanb

In article <19215@prometheus.megatest.UUCP>, djones@megatest.UUCP (Dave Jones) writes:
> 
> 
> I would like to describe to you a small language-extension which I think
> would prove useful. First I will describe the problem to be solved.
> 
> Occasionally, for the sake of efficiency, it is desirable to
> allocate memory for new objects of a given class from a pool of preallocated
> packets, sized by the sizeof() operator. It has been my experience that this
> practice can improve the performance of some applications very significantly.
> We therefore redefine the "new" and "delete" operators for the class.
> 
> class Class1 {
>    		char goodies[SIZE];
> 	public:
> 		void *operator new(size_t);   // ignores the size_t
> 		void  operator delete(void *);
> 		// etc..
> };
> 
[Detail omitted]
> 		Class1 *operator new();
> 		void    operator delete(Class1*);

Sounds plausible. As a workround, would the following work?
void *Class1::operator new(size_t s)
{
    // If default new doesn't work, Class2 needs to redefine operator new anyway
    if (s != sizeof(Class1))
	return ::operator new(s);  

    // Do fixed pool stuff here
}