Re: [boost] really smart pointers submission

From: Fabrice Truillot (fte_at_[hidden])
Date: 2000-07-17 16:44:04

on 17.7.2000 21:54, Thant Tessman at thant_at_[hidden] wrote:

> 
> Okay, here they are. I've also included a very simple test program.
> ("circ_ptr" isn't the greatest name, but in my original implementation
> they're called "Ptr".)

Can I suggest an optimisation ? In your RawHandle, you can use some sort of
union between the void* raw pointer and the boolean. On most
implementations, the pointers are always at least 2-byte aligned (4-bytes
for my Macintosh). So, you can use the least significant bit to store your
boolean.

Under CodeWarrior 5.3, MacOS, sizeof (RawPointer) == 8, and with the
proposed optimisation, 4 bytes.

Hints :

struct pointer_and_bit
{
    void* ptr;

    bool bit () { return (ptr & 1); };
    void bit (bool b)
        {
            if (b) ptr |= 1;
            else ptr &= ~1;
        };

    ... operator -> ...
};

Sorry for this java/c++ pseudo-code. Some type cast must be applied too.

Fab'
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