self.state[:self.offset] ^= self.buf[^self.offset..];

array::zip_with_into(self.state[:self.offset], self.buf[^self.offset..], fn char (char a, char b) => a ^ b);

fn void zip() => @pool()
{
	char[] left = "abcde";
	long[] right = { -1, 0x8000, 0 };

	Pair{char, long}[] expected = { {'a', -1}, {'b', 0x8000}, {'c', 0} };

	Pair{char, long}[] zipped = array::tzip(left, right);

	assert(zipped.len == 3);
	foreach (i, c : zipped) assert(c == expected[i], "Mismatch on index %d: %s (actual) != %s (expected)", i, c, expected[i]);
}

fn void zip_with_longest_fill_pointers() => @pool()
{
	ZString field = "0123456789abcdefghijklmnopqrstuvwxyz-_=!";

	char*[] left = { &field[3], &field[1] };
	char[] right = { 0x05, 0x04, 0x0A, 0x10, 0x11 };

	char[] expected = "85agh";

	char[] zipped = array::tzip_with_longest(left, right, fn char (char* a, char b) => a[b], &field[0]);

	assert(zipped.len == 5);
	foreach (i, c : zipped) test::@check(c == expected[i], "Mismatch on index %d: %s (actual) != %s (expected)", i, c, expected[i]);
}

fn void zip_with_into()
{
	char[] left = { '1', '2', '3', '4' };
	String[6] right = { "one", "two", "three", "four", "five", "six" };

	char[] expected = { '4', '5', '8', '8' };

	array::zip_with_into(left, right, fn char (char a, String b) => a + (char)b.len);

	assert(left.len == 4);
	foreach (i, c : left) test::@check(c == expected[i], "Mismatch on index %d: %s (actual) != %s (expected)", i, c, expected[i]);
}