Re: Stack-based @nogc dynamic array

[Mike Franklin via Digitalmars-d-learn]

On Thursday, 16 May 2019 at 12:16:26 UTC, Marco de Wild wrote:

Or are there any tips to roll my own implementation?

I took a stab at it:

---
@nogc:
nothrow:
pure:

struct NoGcArray(size_t maxSize, T)
{
    private T[maxSize] _buffer;
    private T[] _slice;
    private size_t _frontIndex;

    size_t length() const
    {
        return _slice.length;
    }

    void opOpAssign(string op)(T element)
    {
        static if(op == "~")
        {
            _buffer[_frontIndex + length] = element;
            _slice = _buffer[_frontIndex..(length + 1)];
        }
        else
        {
            static assert(false, "Only concatenation supported");
        }
    }

    T opIndex(size_t index) const
    {
        return _slice[index];
    }

    T front() const
    {
        return _slice[0];
    }

    void popFront()
    {
        _frontIndex++;
        _slice = _slice[1..$];
    }

    bool empty() const
    {
        return _slice.length == 0;
    }
}

void main()
{
    import std.algorithm : sum, map;
    NoGcArray!(4, int) array;
    array ~= 420;
    array ~= 42;
    assert(array.map!(x => x*2).sum == 924);
}
---

Mike