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//===- llvm/ADT/UniqueVector.h ----------------------------------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_ADT_UNIQUEVECTOR_H
#define LLVM_ADT_UNIQUEVECTOR_H
#include <cassert>
#include <cstddef>
#include <map>
#include <vector>
namespace llvm {
//===----------------------------------------------------------------------===//
/// UniqueVector - This class produces a sequential ID number (base 1) for each
/// unique entry that is added. T is the type of entries in the vector. This
/// class should have an implementation of operator== and of operator<.
/// Entries can be fetched using operator[] with the entry ID.
template<class T> class UniqueVector {
public:
using VectorType = typename std::vector<T>;
using iterator = typename VectorType::iterator;
using const_iterator = typename VectorType::const_iterator;
private:
// Map - Used to handle the correspondence of entry to ID.
std::map<T, unsigned> Map;
// Vector - ID ordered vector of entries. Entries can be indexed by ID - 1.
VectorType Vector;
public:
/// insert - Append entry to the vector if it doesn't already exist. Returns
/// the entry's index + 1 to be used as a unique ID.
unsigned insert(const T &Entry) {
// Check if the entry is already in the map.
unsigned &Val = Map[Entry];
// See if entry exists, if so return prior ID.
if (Val) return Val;
// Compute ID for entry.
Val = static_cast<unsigned>(Vector.size()) + 1;
// Insert in vector.
Vector.push_back(Entry);
return Val;
}
/// idFor - return the ID for an existing entry. Returns 0 if the entry is
/// not found.
unsigned idFor(const T &Entry) const {
// Search for entry in the map.
typename std::map<T, unsigned>::const_iterator MI = Map.find(Entry);
// See if entry exists, if so return ID.
if (MI != Map.end()) return MI->second;
// No luck.
return 0;
}
/// operator[] - Returns a reference to the entry with the specified ID.
const T &operator[](unsigned ID) const {
assert(ID-1 < size() && "ID is 0 or out of range!");
return Vector[ID - 1];
}
/// Return an iterator to the start of the vector.
iterator begin() { return Vector.begin(); }
/// Return an iterator to the start of the vector.
const_iterator begin() const { return Vector.begin(); }
/// Return an iterator to the end of the vector.
iterator end() { return Vector.end(); }
/// Return an iterator to the end of the vector.
const_iterator end() const { return Vector.end(); }
/// size - Returns the number of entries in the vector.
size_t size() const { return Vector.size(); }
/// empty - Returns true if the vector is empty.
bool empty() const { return Vector.empty(); }
/// reset - Clears all the entries.
void reset() {
Map.clear();
Vector.resize(0, 0);
}
};
} // end namespace llvm
#endif // LLVM_ADT_UNIQUEVECTOR_H
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