NLEFT_CONTIG
#define NBOTH_CONTIG (NLEFT_CONTIG | NRIGHT_CONTIG)
state |= NLEFT_CONTIG;
switch (state & (NLEFT_CONTIG | NRIGHT_CONTIG | NHOLE)) {
case NLEFT_CONTIG | NRIGHT_CONTIG:
case NLEFT_CONTIG: