Function bit_reverse

KeyboardVisualizerCommon/chuck_fft.c:268–284

----------------------------------------------------------------------------- name: bit_reverse() desc: bitreverse places float array x containing N/2 complex values into bit-reversed order -----------------------------------------------------------------------------

//       into bit-reversed order
//-----------------------------------------------------------------------------
void bit_reverse(float * x, long N)
{
    float rtemp, itemp;
    long i, j, m;
    for (i = j = 0; i < N; i += 2, j += m)
    {
        if (j > i)
        {
            rtemp = x[j]; itemp = x[j + 1]; /* complex exchange */
            x[j] = x[i]; x[j + 1] = x[i + 1];
            x[i] = rtemp; x[i + 1] = itemp;
        }

        for (m = N >> 1; m >= 2 && j >= m; m >>= 1)
            j -= m;
    }
}