Each of the r123arrayNxW is a fixed size array of N W-bit unsigned integers. It is functionally equivalent to the C++0x std::array<N, uintW_t>, but does not require C++0x features or libraries.

In addition to meeting most of the requirements of a Container, it also has a member function, incr(), which increments the zero-th element and carrys overflows into higher indexed elements. Thus, by using incr(), sequences of up to 2^(N*W) distinct values can be produced.

If SSE is supported by the compiler, then the class r123array1xm128i is also defined, in which the data member is an array of one r123128i object.