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// This is based on the following:
//===- llvm/ADT/SmallSet.h - 'Normally small' sets --------------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file defines the CompactSet class.
//
//===----------------------------------------------------------------------===//
#pragma once
#include "compact_vector.h"
#include <cstddef>
#include <iterator>
#include <set>
#include <type_traits>
namespace NYT {
///////////////////////////////////////////////////////////////////////////////
//! Maintains a set of unique values, optimizing for the case
//! when the set is small (less than N).
/*!
* In this case, the set can be maintained with no mallocs.
* If the set gets large, we expand to using an
* std::set to maintain reasonable lookup times.
*
* Note that any modification of the set may invalidate *all* iterators.
*/
template <typename T, size_t N, typename C = std::less<T>, typename A = std::allocator<T>>
class TCompactSet
{
public:
class const_iterator;
using size_type = std::size_t;
using key_type = T;
TCompactSet() = default;
TCompactSet(const A& allocator);
[[nodiscard]] bool empty() const;
size_type size() const;
const T& front() const;
size_type count(const T& v) const;
bool contains(const T& v) const;
std::pair<const_iterator, bool> insert(const T& v);
template <typename TIter>
void insert(TIter i, TIter e);
bool erase(const T& v);
void clear();
const_iterator begin() const;
const_iterator cbegin() const;
const_iterator end() const;
const_iterator cend() const;
private:
// Use a TCompactVector to hold the elements here (even though it will never
// reach its 'large' stage) to avoid calling the default ctors of elements
// we will never use.
TCompactVector<T, N> Vector_;
std::set<T, C, A> Set_;
using TSetConstIterator = typename std::set<T, C, A>::const_iterator;
using TVectorConstIterator = typename TCompactVector<T, N>::const_iterator;
bool is_small() const;
};
///////////////////////////////////////////////////////////////////////////////
} // namespace NYT
#define COMPACT_SET_INL_H_
#include "compact_set-inl.h"
#undef COMPACT_SET_INL_H_
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