usr.bin/grep/dfa.c

1638    Lastpos:  The lastpos of a node is the set of positions that could
1641    * EMPTY leaves have empty lastpos.
1642    * The lastpos of a nonempty leaf is that leaf itself.
1643    * The lastpos of a QMARK, STAR, or PLUS node is the lastpos of its
1645    * The lastpos of a CAT node is the lastpos of its right argument, union
1646      the lastpos of the left if the right argument is nullable.
1647    * The lastpos of an OR node is the union of the lastpos of each argument.
1657      the follow of every node in the lastpos.
1659      the follow of every node in the lastpos of the first argument.
1672   int *nlastpos;		/* Element count stack for lastpos sets. */
1673   position *lastpos;		/* Array where lastpos elements are stored. */
1704   MALLOC(lastpos, position, d->nleaves);
1705   o_lastpos = lastpos, lastpos += d->nleaves;
1723 	/* The firstpos and lastpos of the empty leaf are both empty. */
1730 	   of every element in the lastpos. */
1733 	pos = lastpos;
1750 	   follow of every element in the lastpos of the first argument. */
1753 	pos = lastpos + nlastpos[-1];
1770 	/* The lastpos of a CAT node is the lastpos of the second argument,
1776 	    pos = lastpos + nlastpos[-2];
1778 	      pos[j] = lastpos[j];
1779 	    lastpos += nlastpos[-2];
1795 	/* The lastpos is the union of the lastpos of each argument. */
1812 	/* This position is in its own firstpos and lastpos. */
1814 	--firstpos, --lastpos;
1815 	firstpos->index = lastpos->index = i;
1816 	firstpos->constraint = lastpos->constraint = NO_CONSTRAINT;
1835       fprintf(stderr, "\n lastpos:");
1838 	  fprintf(stderr, " %d:", lastpos[j].index);
1839 	  prtok(d->tokens[lastpos[j].index]);