Re: Single-Allocation Variable-Sized Array

[Alex Parrill via Digitalmars-d-learn]

On Wednesday, 18 May 2016 at 21:28:56 UTC, Nordlöw wrote:
What's the preferred way in D to implement single-allocation 
variable-sized arrays such as

/** Single-Allocation Array. */
struct ArrayN
{
    ubyte length;  // <= maxLength
    size room;     // allocated length
    ubyte[0] data; // `room` number of bytes follows
}

where insertion/deletion typically is done via

    ArrayN* pushBack(ArrayN*, ubyte element);
    ArrayN* popBack(ArrayN*);

which, when needed, will reallocate a new larger/smaller 
`ArrayN`

?

Further, what's the official name for this structure?

In C it's called a variable-length struct or object. I don't 
think D implements them, but this could probably work:

struct Foo {
    size_t len;

    ubyte[] data() @property {
        auto thisptr = cast(ubyte*)(&this);
        return thisptr[Foo.sizeof..(Foo.sizeof+len)];
    }
}