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+//===- llvm/ADT/Trie.h ---- Generic trie structure --------------*- C++ -*-===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This class defines a generic trie structure. The trie structure
+// is immutable after creation, but the payload contained within it is not.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_ADT_TRIE_H
+#define LLVM_ADT_TRIE_H
+
+#include "llvm/ADT/GraphTraits.h"
+#include "llvm/Support/DOTGraphTraits.h"
+
+#include <vector>
+
+namespace llvm {
+
+// FIXME:
+// - Labels are usually small, maybe it's better to use SmallString
+// - Should we use char* during construction?
+// - Should we templatize Empty with traits-like interface?
+
+template<class Payload>
+class Trie {
+ friend class GraphTraits<Trie<Payload> >;
+ friend class DOTGraphTraits<Trie<Payload> >;
+public:
+ class Node {
+ friend class Trie;
+
+ public:
+ typedef std::vector<Node*> NodeVectorType;
+ typedef typename NodeVectorType::iterator iterator;
+ typedef typename NodeVectorType::const_iterator const_iterator;
+
+ private:
+ enum QueryResult {
+ Same = -3,
+ StringIsPrefix = -2,
+ LabelIsPrefix = -1,
+ DontMatch = 0,
+ HaveCommonPart
+ };
+
+ struct NodeCmp {
+ bool operator() (Node* N1, Node* N2) {
+ return (N1->Label[0] < N2->Label[0]);
+ }
+ bool operator() (Node* N, char Id) {
+ return (N->Label[0] < Id);
+ }
+ };
+
+ std::string Label;
+ Payload Data;
+ NodeVectorType Children;
+
+ // Do not implement
+ Node(const Node&);
+ Node& operator=(const Node&);
+
+ inline void addEdge(Node* N) {
+ if (Children.empty())
+ Children.push_back(N);
+ else {
+ iterator I = std::lower_bound(Children.begin(), Children.end(),
+ N, NodeCmp());
+ // FIXME: no dups are allowed
+ Children.insert(I, N);
+ }
+ }
+
+ inline void setEdge(Node* N) {
+ char Id = N->Label[0];
+ iterator I = std::lower_bound(Children.begin(), Children.end(),
+ Id, NodeCmp());
+ assert(I != Children.end() && "Node does not exists!");
+ *I = N;
+ }
+
+ QueryResult query(const std::string& s) const {
+ unsigned i, l;
+ unsigned l1 = s.length();
+ unsigned l2 = Label.length();
+
+ // Find the length of common part
+ l = std::min(l1, l2);
+ i = 0;
+ while ((i < l) && (s[i] == Label[i]))
+ ++i;
+
+ if (i == l) { // One is prefix of another, find who is who
+ if (l1 == l2)
+ return Same;
+ else if (i == l1)
+ return StringIsPrefix;
+ else
+ return LabelIsPrefix;
+ } else // s and Label have common (possible empty) part, return its length
+ return (QueryResult)i;
+ }
+
+ public:
+ inline explicit Node(const Payload& data, const std::string& label = ""):
+ Label(label), Data(data) { }
+
+ inline const Payload& data() const { return Data; }
+ inline void setData(const Payload& data) { Data = data; }
+
+ inline const std::string& label() const { return Label; }
+
+#if 0
+ inline void dump() {
+ std::cerr << "Node: " << this << "\n"
+ << "Label: " << Label << "\n"
+ << "Children:\n";
+
+ for (iterator I = Children.begin(), E = Children.end(); I != E; ++I)
+ std::cerr << (*I)->Label << "\n";
+ }
+#endif
+
+ inline Node* getEdge(char Id) {
+ Node* fNode = NULL;
+ iterator I = std::lower_bound(Children.begin(), Children.end(),
+ Id, NodeCmp());
+ if (I != Children.end() && (*I)->Label[0] == Id)
+ fNode = *I;
+
+ return fNode;
+ }
+
+ inline iterator begin() { return Children.begin(); }
+ inline const_iterator begin() const { return Children.begin(); }
+ inline iterator end () { return Children.end(); }
+ inline const_iterator end () const { return Children.end(); }
+
+ inline size_t size () const { return Children.size(); }
+ inline bool empty() const { return Children.empty(); }
+ inline const Node* &front() const { return Children.front(); }
+ inline Node* &front() { return Children.front(); }
+ inline const Node* &back() const { return Children.back(); }
+ inline Node* &back() { return Children.back(); }
+
+ };
+
+private:
+ std::vector<Node*> Nodes;
+ Payload Empty;
+
+ inline Node* addNode(const Payload& data, const std::string label = "") {
+ Node* N = new Node(data, label);
+ Nodes.push_back(N);
+ return N;
+ }
+
+ inline Node* splitEdge(Node* N, char Id, size_t index) {
+ Node* eNode = N->getEdge(Id);
+ assert(eNode && "Node doesn't exist");
+
+ const std::string &l = eNode->Label;
+ assert(index > 0 && index < l.length() && "Trying to split too far!");
+ std::string l1 = l.substr(0, index);
+ std::string l2 = l.substr(index);
+
+ Node* nNode = addNode(Empty, l1);
+ N->setEdge(nNode);
+
+ eNode->Label = l2;
+ nNode->addEdge(eNode);
+
+ return nNode;
+ }
+
+ // Do not implement
+ Trie(const Trie&);
+ Trie& operator=(const Trie&);
+
+public:
+ inline explicit Trie(const Payload& empty):Empty(empty) {
+ addNode(Empty);
+ }
+ inline ~Trie() {
+ for (unsigned i = 0, e = Nodes.size(); i != e; ++i)
+ delete Nodes[i];
+ }
+
+ inline Node* getRoot() const { return Nodes[0]; }
+
+ bool addString(const std::string& s, const Payload& data);
+ const Payload& lookup(const std::string& s) const;
+
+};
+
+// Define this out-of-line to dissuade the C++ compiler from inlining it.
+template<class Payload>
+bool Trie<Payload>::addString(const std::string& s, const Payload& data) {
+ Node* cNode = getRoot();
+ Node* tNode = NULL;
+ std::string s1(s);
+
+ while (tNode == NULL) {
+ char Id = s1[0];
+ if (Node* nNode = cNode->getEdge(Id)) {
+ typename Node::QueryResult r = nNode->query(s1);
+
+ switch (r) {
+ case Node::Same:
+ case Node::StringIsPrefix:
+ // Currently we don't allow to have two strings in the trie one
+ // being a prefix of another. This should be fixed.
+ assert(0 && "FIXME!");
+ return false;
+ case Node::DontMatch:
+ assert(0 && "Impossible!");
+ return false;
+ case Node::LabelIsPrefix:
+ s1 = s1.substr(nNode->label().length());
+ cNode = nNode;
+ break;
+ default:
+ nNode = splitEdge(cNode, Id, r);
+ tNode = addNode(data, s1.substr(r));
+ nNode->addEdge(tNode);
+ }
+ } else {
+ tNode = addNode(data, s1);
+ cNode->addEdge(tNode);
+ }
+ }
+
+ return true;
+}
+
+template<class Payload>
+const Payload& Trie<Payload>::lookup(const std::string& s) const {
+ Node* cNode = getRoot();
+ Node* tNode = NULL;
+ std::string s1(s);
+
+ while (tNode == NULL) {
+ char Id = s1[0];
+ if (Node* nNode = cNode->getEdge(Id)) {
+ typename Node::QueryResult r = nNode->query(s1);
+
+ switch (r) {
+ case Node::Same:
+ tNode = nNode;
+ break;
+ case Node::StringIsPrefix:
+ return Empty;
+ case Node::DontMatch:
+ assert(0 && "Impossible!");
+ return Empty;
+ case Node::LabelIsPrefix:
+ s1 = s1.substr(nNode->label().length());
+ cNode = nNode;
+ break;
+ default:
+ return Empty;
+ }
+ } else
+ return Empty;
+ }
+
+ return tNode->data();
+}
+
+template<class Payload>
+struct GraphTraits<Trie<Payload> > {
+ typedef Trie<Payload> TrieType;
+ typedef typename TrieType::Node NodeType;
+ typedef typename NodeType::iterator ChildIteratorType;
+
+ static inline NodeType *getEntryNode(const TrieType& T) {
+ return T.getRoot();
+ }
+
+ static inline ChildIteratorType child_begin(NodeType *N) {
+ return N->begin();
+ }
+ static inline ChildIteratorType child_end(NodeType *N) { return N->end(); }
+
+ typedef typename std::vector<NodeType*>::const_iterator nodes_iterator;
+
+ static inline nodes_iterator nodes_begin(const TrieType& G) {
+ return G.Nodes.begin();
+ }
+ static inline nodes_iterator nodes_end(const TrieType& G) {
+ return G.Nodes.end();
+ }
+
+};
+
+template<class Payload>
+struct DOTGraphTraits<Trie<Payload> > : public DefaultDOTGraphTraits {
+ typedef typename Trie<Payload>::Node NodeType;
+ typedef typename GraphTraits<Trie<Payload> >::ChildIteratorType EdgeIter;
+
+ static std::string getGraphName(const Trie<Payload>& T) {
+ return "Trie";
+ }
+
+ static std::string getNodeLabel(NodeType* Node, const Trie<Payload>& T) {
+ if (T.getRoot() == Node)
+ return "<Root>";
+ else
+ return Node->label();
+ }
+
+ static std::string getEdgeSourceLabel(NodeType* Node, EdgeIter I) {
+ NodeType* N = *I;
+ return N->label().substr(0, 1);
+ }
+
+ static std::string getNodeAttributes(const NodeType* Node,
+ const Trie<Payload>& T) {
+ if (Node->data() != T.Empty)
+ return "color=blue";
+
+ return "";
+ }
+
+};
+
+} // end of llvm namespace
+
+#endif // LLVM_ADT_TRIE_H
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