PUCAN_FLTSTD_ROW_IDX_BITS
if ((idx < 0) || (idx >= (1 << PUCAN_FLTSTD_ROW_IDX_BITS))) {
n = 1 << PUCAN_FLTSTD_ROW_IDX_BITS;
#define PUCAN_FLTSTD_ROW_IDX_MAX ((1 << PUCAN_FLTSTD_ROW_IDX_BITS) - 1)