ObjectArray

const ObjectArray = struct

File

Code

const ObjectArray = struct {
    const ObjectPointer = *anyopaque;

    // content of the array
    slots: []?ObjectPointer,

    /// create a new ObjectArray with n slots. must call deinit() to deallocate.
    pub fn init(n: usize) *ObjectArray {
        const array = simple_allocator.alloc(ObjectArray);

        array.* = ObjectArray{
            .slots = simple_allocator.allocSlice(?ObjectPointer, n),
        };

        for (array.slots) |*object| {
            object.* = null;
        }

        return array;
    }

    /// deallocate the ObjectArray.
    pub fn deinit(self: *ObjectArray) void {
        // deallocated used objects in the array
        for (self.slots) |*object| {
            simple_allocator.free(object.*);
        }
        simple_allocator.free(self.slots);
        simple_allocator.free(self);
    }

    /// resize the ObjectArray if needed.
    pub fn ensureLength(self: *ObjectArray, new_len: usize) *ObjectArray {
        const old_len = self.slots.len;

        if (old_len > new_len) {
            return self;
        }

        // reallocate
        self.slots = simple_allocator.reallocSlice(?ObjectPointer, self.slots, new_len);

        // init newly added slots
        for (self.slots[old_len..]) |*object| {
            object.* = null;
        }

        return self;
    }

    /// Retrieve the pointer at request index, using control to initialize it if needed.
    pub fn getPointer(self: *ObjectArray, index: usize, control: *emutls_control) ObjectPointer {
        if (self.slots[index] == null) {
            // initialize the slot
            const size = control.size;
            const alignment: u29 = @truncate(control.alignment);

            var data = simple_allocator.advancedAlloc(alignment, size);
            errdefer simple_allocator.free(data);

            if (control.default_value) |value| {
                // default value: copy the content to newly allocated object.
                @memcpy(data[0..size], @as([*]const u8, @ptrCast(value)));
            } else {
                // no default: return zeroed memory.
                @memset(data[0..size], 0);
            }

            self.slots[index] = data;
        }

        return self.slots[index].?;
    }
}