chromium/base/stl_util.h

// Copyright 2011 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

// Derived from google3/util/gtl/stl_util.h

#ifndef BASE_STL_UTIL_H_
#define BASE_STL_UTIL_H_

#include <algorithm>
#include <forward_list>
#include <iterator>
#include <type_traits>

#include "base/check.h"
#include "base/ranges/algorithm.h"

namespace base {

namespace internal {

IsRandomAccessIter;

}  // namespace internal

// Returns a const reference to the underlying container of a container adapter.
// Works for std::priority_queue, std::queue, and std::stack.
template <class A>
const typename A::container_type& GetUnderlyingContainer(const A& adapter) { … }

// Clears internal memory of an STL object.
// STL clear()/reserve(0) does not always free internal memory allocated
// This function uses swap/destructor to ensure the internal memory is freed.
template<class T>
void STLClearObject(T* obj) { … }

// Returns a new ResultType containing the difference of two sorted containers.
template <typename ResultType, typename Arg1, typename Arg2>
ResultType STLSetDifference(const Arg1& a1, const Arg2& a2) { … }

// Returns a new ResultType containing the union of two sorted containers.
template <typename ResultType, typename Arg1, typename Arg2>
ResultType STLSetUnion(const Arg1& a1, const Arg2& a2) { … }

// Returns a new ResultType containing the intersection of two sorted
// containers.
template <typename ResultType, typename Arg1, typename Arg2>
ResultType STLSetIntersection(const Arg1& a1, const Arg2& a2) { … }

// A helper class to be used as the predicate with |EraseIf| to implement
// in-place set intersection. Helps implement the algorithm of going through
// each container an element at a time, erasing elements from the first
// container if they aren't in the second container. Requires each container be
// sorted. Note that the logic below appears inverted since it is returning
// whether an element should be erased.
template <class Collection>
class IsNotIn { … };

}  // namespace base

#endif  // BASE_STL_UTIL_H_