Path: chuka.playstation.co.uk!news
From: sosman@terratron.com (Steven Osman)
Newsgroups: scee.yaroze.beginners
Subject: Re: A Problem with Malloc and a question about InitHeap
Date: Mon, 13 Dec 1999 05:27:38 GMT
Organization: PlayStation Net Yaroze (SCEE)
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References: <3851a5b1.5208772@news.playstation.co.uk> <3852CCEA.714FF3B2@identicalsoftware.com>
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Incidentally, at the cost of 4 bytes of memory you can make it
faster...

void AddCamera(Camera ** listStart, Camera **listEnd) {
    Camera *newCamera=(Camera *) malloc(sizeof(Camera));

    if (*listEnd) {
        *listEnd->next=newCamera;
    } else {
        *listStart=newCamera;
    }

    *listEnd=newCamera;
    ReadCamera(newCamera);
}

Just keep the start and end pointers of the list (make sure they are
both initialized to NULL).

Steven

On Sat, 11 Dec 1999 22:15:06 +0000, Dennis Payne
<dulsi@identicalsoftware.com> wrote:

>> void AddCamera(Camera* list)
>> {
>>         while( list!= NULL ) list=list->next;
>>         list = (Camera*) malloc( sizeof(Camera) );
>>         ReadCamera(list);
>> }
>
>The code is wrong (I think).  To do the equivelent of the macro:
>void AddCamera(Camera** list)
>{
>        while( (*list)!= NULL ) (*list)=(*list)->next;
>        (*list) = (Camera*) malloc( sizeof(Camera) );
>        ReadCamera(*list);
>}
>
>I don't think this is what you want though.  This iterates through
>the list but does not add the item to the list.  It also destroys
>the pointers to the list in the process.  Here's what I think
>you want:
>
>void AddCamera(Camera** list)
>{
>        Camera *prev;
>	if ((*list) == NULL)
>        {
>              (*list) = (Camera*) malloc( sizeof(Camera) );
>              ReadCamera(*list);
>        }
>        else
>        {
>              prev = *list;
>              while( prev->next != NULL ) prev=prev->next;
>              prev->next = (Camera*) malloc( sizeof(Camera) );
>              ReadCamera(prev->next);
>        }
>}
>
>(In C++ you would pass in a "Camera *&list".)
>
>If you need an explaination of what this is doing let me know.
>
>> BTW - InitHeap seems to have no effect. Oh and one last thing how do
>> you reclaim the memory after you have loaded your files into video
>> memory or into their structures(I parse a raw binary file also).
>
>After you're done with the files simply use the memory.  For
>example if you loaded all the graphic images then you could use
>InitHeap with the memory addresses of where the images were stored.
>(I have no experience with InitHeap so I don't know why it would be
>a problem.)
>
>Dennis Payne
>dulsi@identicalsoftware.com