public static SuffixTree create(Text text) {
SuffixTree tree = new SuffixTree(text);
Suffix active = new Suffix(tree.root, 0, -1);
for (int i = 0; i < text.length(); i++) {
tree.addPrefix(active, i);
}
return tree;
}
private void addPrefix(Suffix active, int endIndex) {
Node lastParentNode = null;
Node parentNode;
while (true) {
Edge edge;
parentNode = active.getOriginNode();
// Step 1 is to try and find a matching edge for the given node.
// If a matching edge exists, we are done adding edges, so we break out of this big loop.
if (active.isExplicit()) {
edge = active.getOriginNode().findEdge(symbolAt(endIndex));
if (edge != null) {
break;
}
} else {
// implicit node, a little more complicated
edge = active.getOriginNode().findEdge(symbolAt(active.getBeginIndex()));
int span = active.getSpan();
if (Objects.equal(symbolAt(edge.getBeginIndex() + span + 1), symbolAt(endIndex))) {
break;
}
parentNode = edge.splitEdge(active);
}
// We didn't find a matching edge, so we create a new one, add it to the tree at the parent
// node position,
// and insert it into the hash table. When we create a new node, it also means we need to
// create
// a suffix link to the new node from the last node we visited.
Edge newEdge = new Edge(endIndex, text.length() - 1, parentNode);
newEdge.insert();
updateSuffixNode(lastParentNode, parentNode);
lastParentNode = parentNode;
// This final step is where we move to the next smaller suffix
if (active.getOriginNode() == root) {
active.incBeginIndex();
} else {
active.changeOriginNode();
}
active.canonize();
}
updateSuffixNode(lastParentNode, parentNode);
active.incEndIndex();
// Now the endpoint is the next active point
active.canonize();
}
/**
* Appends a subsequence of the specified text. If the specified character sequence is <code>null
* </code> this method is equivalent to <code>append("null")</code>.
*
* @param txt the text to append or <code>null</code>.
* @param start the index of the first character to append.
* @param end the index after the last character to append.
* @return <code>this</code>
* @throws IndexOutOfBoundsException if <code>(start < 0) || (end < 0)
* || (start > end) || (end > txt.length())</code>
*/
public final TextBuilder append(Text txt, int start, int end) {
if (txt == null) return append("null");
if ((start < 0) || (end < 0) || (start > end) || (end > txt.length()))
throw new IndexOutOfBoundsException();
int newLength = _length + end - start;
while (_capacity < newLength) {
increaseCapacity();
}
for (int i = start, j = _length; i < end; ) {
char[] chars = _high[j >> B1];
int dstBegin = j & M1;
int inc = MathLib.min(C1 - dstBegin, end - i);
txt.getChars(i, (i += inc), chars, dstBegin);
j += inc;
}
_length = newLength;
return this;
}
/**
* Appends the specified text to this text builder. If the specified text is <code>null</code>
* this method is equivalent to <code>append("null")</code>.
*
* @param txt the text to append or <code>null</code>.
* @return <code>this</code>
*/
public final TextBuilder append(Text txt) {
return (txt == null) ? append("null") : append(txt, 0, txt.length());
}
