T[new]

[Andrei Alexandrescu]

Lionello Lunesu wrote:
> 
> "Andrei Alexandrescu" <SeeWebsiteForEmail at erdani.org> wrote in message 
> news:h5ndt0$1blj$1 at digitalmars.com...
>> bearophile wrote:
>>> Walter Bright:
>>>> Under the hood, a T[new] will be a single pointer to a library 
>>>> defined type. This library defined type will likely contain three 
>>>> properties:
>>>
>>> I have another question: are there some performance penalities in 
>>> using such arrays for normal random access operations?
>>
>> One extra indirection, usually nearby.
>>
>> Andrei
> 
> If the size and capacity get added to the begining of the memory block 
> containing the data, only an extra offset is needed. The compiler could 
> emit "mov eax, [esi*4 + 8]" or something. Look ma, no extra indirection :)

I wish too. The problem is that when you resize the array, the control 
block will not refer to the adjacent chunk.


Andrei