Add std.BoundedArray(u5, 32) to hashmap

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21

Remains the question: how to garantuee zero’s for the part after “len”?

22

fields are always public so you can zero the buffer yourself @memSet if you weren’t aware of it before :3

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23 
var suffix : std.BoundedArray(u5, 32) = .{
    .buffer = [_]u5{0} ** 32,
    .len = 0,
};

The 3 extra bits in the u5 will still be set to undefined, but autoHash will correctly avoid those bits (I assume autoEql will also).

24

Note that it’s still not a full solution to the problem, since e.g. this test will still fail:

test "bounded array auto hash map" {
    var map: std.AutoHashMap(std.BoundedArray(u5, 32), void) = .init(std.testing.allocator);
    defer map.deinit();

    var arr: std.BoundedArray(u5, 32) = .{
        .buffer = [_]u5{ 1, 2, 3 } ++ [_]u5{0} ** 29,
        .len = 3,
    };

    try map.putNoClobber(arr, {});

    try arr.append(4);

    // ...

    _ = arr.pop();

    try std.testing.expect(map.contains(arr));
}

The only way to make this work in all cases would be to use a custom BoundedArray implementation that sets all elements outside the len to 0 after every modification to the list, but that’s just pointless extra work to enable using an autoHash function that isn’t suited to this use case.

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