Casts and @trusted

[Anonymous via Digitalmars-d-learn]

That really is it. The other methods are just other gets to the 
buffer, like this:

T[] get_dup(TS strat=TS.cyclic)(size_t n) const {
	static if (strat==TS.once) size_t numreads = fixNToFill(n);
	else size_t numreads = n;
	auto ret = new T[](numreads);
	
	size_t read = index;
	foreach(i;0..numreads) {
		ret[i] = _buffer[read].dup;
		if (read == 0) read = fill-1;
		else --read;
	}

	return ret;
}

But ah, the .ptr property is not supposed to work for array 
element? In any case it still works as cast(T*) &(_buffer[read]). 
Here's the unittest I slapped together:

unittest {
	char[5] hello = "hello";
	char[5] world = "world";
	char[5] forty = "forty";
	char[5] three = "three";
	char[5] gdbye = "gdbye";
	alias chars_t = char[5];
	chars_t[] foo = [hello,world,forty,three];
	chars_t[] oob = foo.dup.reverse;
	StaticRingBuffer!(chars_t,4) bar;
	bar.put(foo);
	assert(bar.index==3);
	const(chars_t)*[4] ptrs;
	bar.get_ref(4,ptrs);
	assert(bar.get_dup(4) == oob);
	foreach(i,ptr; ptrs) assert(*ptr == oob[i]);
	assert(bar.get_dup(7) == 
[three,forty,world,hello,three,forty,world]);
	bar.put("gdbye");
	assert(bar.index==0);
	assert(bar.get_dup(4) == [gdbye,three,forty,world]);
	assert(bar.get_dup(7) == 
[gdbye,three,forty,world,gdbye,three,forty]);
}

But now I see my problem is that a simple const(T*)[N] already 
initializes its elements to null, so nothing past that should 
modify them. And without the casts, the type on &(_buffer[read]) 
is a const(T*) instead of something else which finally makes 
sense. Somehow I thought .ptr was a property of everything.

And now I realize that I can just put the ptr array within the 
get scope, and return it, to initialize a lhs const(T*)[] by 
value. I was making things hard on myself by trying to modify a 
passed-in buffer.