LookupLenCode

const LookupLenCode = packed struct(u5) {
    code: ShortLenCode,

    const code_table = table: {
        var codes: [256]ShortLenCode = undefined;
        for (0.., &codes) |v, *c| {
            c.* = .fromVal(v);
        }
        break :table codes;
    };

    const base_table = table: {
        var bases: [29]u8 = undefined;
        for (0.., &bases) |c, *b| {
            b.* = ShortLenCode.fromInt(c).base();
        }
        break :table bases;
    };

    pub fn fromVal(v: u8) LookupLenCode {
        return .{ .code = code_table[v] };
    }

    /// `@ctz(return) >= extraBits()`
    pub fn base(c: LookupLenCode) u8 {
        return base_table[c.toInt()];
    }

    pub fn extraBits(c: LookupLenCode) u3 {
        return c.code.extraBits();
    }

    pub fn toInt(c: LookupLenCode) u5 {
        return @bitCast(c);
    }

    pub fn fromInt(x: u5) LookupLenCode {
        return @bitCast(x);
    }
}