mirror of
https://github.com/klzgrad/naiveproxy.git
synced 2024-11-28 00:06:09 +03:00
120 lines
3.7 KiB
C++
120 lines
3.7 KiB
C++
// 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 {
|
|
|
|
template <typename Iter>
|
|
constexpr bool IsRandomAccessIter =
|
|
std::is_same<typename std::iterator_traits<Iter>::iterator_category,
|
|
std::random_access_iterator_tag>::value;
|
|
|
|
} // 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) {
|
|
struct ExposedAdapter : A {
|
|
using A::c;
|
|
};
|
|
return adapter.*&ExposedAdapter::c;
|
|
}
|
|
|
|
// 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) {
|
|
T tmp;
|
|
tmp.swap(*obj);
|
|
// Sometimes "T tmp" allocates objects with memory (arena implementation?).
|
|
// Hence using additional reserve(0) even if it doesn't always work.
|
|
obj->reserve(0);
|
|
}
|
|
|
|
// 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) {
|
|
DCHECK(ranges::is_sorted(a1));
|
|
DCHECK(ranges::is_sorted(a2));
|
|
ResultType difference;
|
|
std::set_difference(a1.begin(), a1.end(),
|
|
a2.begin(), a2.end(),
|
|
std::inserter(difference, difference.end()));
|
|
return difference;
|
|
}
|
|
|
|
// 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) {
|
|
DCHECK(ranges::is_sorted(a1));
|
|
DCHECK(ranges::is_sorted(a2));
|
|
ResultType result;
|
|
std::set_union(a1.begin(), a1.end(),
|
|
a2.begin(), a2.end(),
|
|
std::inserter(result, result.end()));
|
|
return result;
|
|
}
|
|
|
|
// 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) {
|
|
DCHECK(ranges::is_sorted(a1));
|
|
DCHECK(ranges::is_sorted(a2));
|
|
ResultType result;
|
|
std::set_intersection(a1.begin(), a1.end(),
|
|
a2.begin(), a2.end(),
|
|
std::inserter(result, result.end()));
|
|
return result;
|
|
}
|
|
|
|
// 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 {
|
|
public:
|
|
explicit IsNotIn(const Collection& collection)
|
|
: i_(collection.begin()), end_(collection.end()) {}
|
|
|
|
bool operator()(const typename Collection::value_type& x) {
|
|
while (i_ != end_ && *i_ < x)
|
|
++i_;
|
|
if (i_ == end_)
|
|
return true;
|
|
if (*i_ == x) {
|
|
++i_;
|
|
return false;
|
|
}
|
|
return true;
|
|
}
|
|
|
|
private:
|
|
typename Collection::const_iterator i_;
|
|
const typename Collection::const_iterator end_;
|
|
};
|
|
|
|
} // namespace base
|
|
|
|
#endif // BASE_STL_UTIL_H_
|