/**
* Walk down the tree from the given node following the given path
* @param st the suffixtree in question
* @param v the node to start from its children
* @param p the path to walk down and then free
* @return a position corresponding to end
*/
static pos *walk_down( suffixtree *st, node *v, path *p )
{
pos *q=NULL;
int start = path_start( p );
int len = path_len( p );
v = node_find_child( v, st->str, st->str[start] );
while ( len > 0 )
{
if ( len <= node_len(v) )
{
q = pos_create();
q->loc = node_start(v)+len-1;
q->v = v;
break;
}
else
{
start += node_len(v);
len -= node_len(v);
v = node_find_child( v, st->str, st->str[start] );
}
}
path_dispose( p );
return q;
}
int node_end( node *v, int max )
{
if ( node_len(v) == INFINITY )
return max;
else
return v->start+v->len-1;
}
/**
* Find a location of the suffix in the tree.
* @param st the suffixtree in question
* @param j the extension number counting from 0
* @param i the current phase - 1
* @param log the log to record errors in
* @return the position (combined node and edge-offset)
*/
static pos *find_beta( suffixtree *st, int j, int i, plugin_log *log )
{
pos *p;
if ( st->old_j > 0 && st->old_j == j )
{
p = pos_create();
p->loc = st->old_beta.loc;
p->v = st->old_beta.v;
}
else if ( j>i ) // empty string
{
p = pos_create();
p->loc = 0;
p->v = st->root;
}
else if ( j==0 ) // entire string
{
p = pos_create();
p->loc = i;
p->v = st->f;
}
else // walk across tree
{
node *v = st->last.v;
int len = st->last.loc-node_start(st->last.v)+1;
path *q = path_create( node_start(v), len, log );
v = node_parent( v );
while ( v != st->root && node_link(v)==NULL )
{
path_prepend( q, node_len(v) );
v = node_parent( v );
}
if ( v != st->root )
{
v = node_link( v );
p = walk_down( st, v, q );
}
else
{
path_dispose( q );
p = walk_down( st, st->root, path_create(j,i-j+1,log) );
}
}
st->last = *p;
return p;
}
/**
* Find a location of the suffix in the tree.
* @param j the extension number counting from 0
* @param i the current phase - 1
* @return the position (combined node and edge-offset)
*/
static pos *find_beta( int j, int i )
{
pos *p;
if ( old_j > 0 && old_j == j )
{
p = pos_create();
p->loc = old_beta.loc;
p->v = old_beta.v;
}
else if ( j>i ) // empty string
{
p = pos_create();
p->loc = 0;
p->v = root;
}
else if ( j==0 ) // entire string
{
p = pos_create();
p->loc = i;
p->v = f;
}
else // walk across tree
{
node *v = last.v;
int len = last.loc-node_start(last.v)+1;
path *q = path_create( node_start(v), len );
v = node_parent( v );
while ( v != root && node_link(v)==NULL )
{
path_prepend( q, node_len(v) );
v = node_parent( v );
}
if ( v != root )
{
v = node_link( v );
p = walk_down( v, q );
}
else
{
path_dispose( q );
p = walk_down( root, path_create(j,i-j+1) );
}
}
last = *p;
return p;
}
/**
* Is an unattached node equal to a dom-attached node
* @param n the node in the tree
* @param r the unattached node aka range
* @return 1 if they have the same range
*/
static int range_equals_node( node *n, node *r )
{
return node_offset(n)==node_offset(r) && node_len(n)==node_len(r);
}
