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// Copyright 2017 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef BASE_CONTAINERS_FLAT_TREE_H_
#define BASE_CONTAINERS_FLAT_TREE_H_
#include <algorithm>
#include <iterator>
#include <type_traits>
#include <vector>
#include "base/template_util.h"
namespace base {
enum FlatContainerDupes {
KEEP_FIRST_OF_DUPES,
KEEP_LAST_OF_DUPES,
};
namespace internal {
// This is a convenience method returning true if Iterator is at least a
// ForwardIterator and thus supports multiple passes over a range.
template <class Iterator>
constexpr bool is_multipass() {
return std::is_base_of<
std::forward_iterator_tag,
typename std::iterator_traits<Iterator>::iterator_category>::value;
}
// This algorithm is like unique() from the standard library except it
// selects only the last of consecutive values instead of the first.
template <class Iterator, class BinaryPredicate>
Iterator LastUnique(Iterator first, Iterator last, BinaryPredicate compare) {
Iterator replacable = std::adjacent_find(first, last, compare);
// No duplicate elements found.
if (replacable == last)
return last;
first = std::next(replacable);
// Last element is a duplicate but all others are unique.
if (first == last)
return replacable;
// This loop is based on std::adjacent_find but std::adjacent_find doesn't
// quite cut it.
for (Iterator next = std::next(first); next != last; ++next, ++first) {
if (!compare(*first, *next))
*replacable++ = std::move(*first);
}
// Last element should be copied unconditionally.
*replacable++ = std::move(*first);
return replacable;
}
// Uses SFINAE to detect whether type has is_transparent member.
template <typename T, typename = void>
struct IsTransparentCompare : std::false_type {};
template <typename T>
struct IsTransparentCompare<T, void_t<typename T::is_transparent>>
: std::true_type {};
// Implementation -------------------------------------------------------------
// Implementation of a sorted vector for backing flat_set and flat_map. Do not
// use directly.
//
// The use of "value" in this is like std::map uses, meaning it's the thing
// contained (in the case of map it's a <Kay, Mapped> pair). The Key is how
// things are looked up. In the case of a set, Key == Value. In the case of
// a map, the Key is a component of a Value.
//
// The helper class GetKeyFromValue provides the means to extract a key from a
// value for comparison purposes. It should implement:
// const Key& operator()(const Value&).
template <class Key, class Value, class GetKeyFromValue, class KeyCompare>
class flat_tree {
private:
using underlying_type = std::vector<Value>;
public:
// --------------------------------------------------------------------------
// Types.
//
using key_type = Key;
using key_compare = KeyCompare;
using value_type = Value;
// Wraps the templated key comparison to compare values.
class value_compare : public key_compare {
public:
value_compare() = default;
template <class Cmp>
explicit value_compare(Cmp&& compare_arg)
: KeyCompare(std::forward<Cmp>(compare_arg)) {}
bool operator()(const value_type& left, const value_type& right) const {
GetKeyFromValue extractor;
return key_compare::operator()(extractor(left), extractor(right));
}
};
using pointer = typename underlying_type::pointer;
using const_pointer = typename underlying_type::const_pointer;
using reference = typename underlying_type::reference;
using const_reference = typename underlying_type::const_reference;
using size_type = typename underlying_type::size_type;
using difference_type = typename underlying_type::difference_type;
using iterator = typename underlying_type::iterator;
using const_iterator = typename underlying_type::const_iterator;
using reverse_iterator = typename underlying_type::reverse_iterator;
using const_reverse_iterator =
typename underlying_type::const_reverse_iterator;
// --------------------------------------------------------------------------
// Lifetime.
//
// Constructors that take range guarantee O(N * log^2(N)) + O(N) complexity
// and take O(N * log(N)) + O(N) if extra memory is available (N is a range
// length).
//
// Assume that move constructors invalidate iterators and references.
//
// The constructors that take ranges, lists, and vectors do not require that
// the input be sorted.
flat_tree();
explicit flat_tree(const key_compare& comp);
template <class InputIterator>
flat_tree(InputIterator first,
InputIterator last,
FlatContainerDupes dupe_handling = KEEP_FIRST_OF_DUPES,
const key_compare& comp = key_compare());
flat_tree(const flat_tree&);
flat_tree(flat_tree&&);
flat_tree(std::vector<value_type> items,
FlatContainerDupes dupe_handling = KEEP_FIRST_OF_DUPES,
const key_compare& comp = key_compare());
flat_tree(std::initializer_list<value_type> ilist,
FlatContainerDupes dupe_handling = KEEP_FIRST_OF_DUPES,
const key_compare& comp = key_compare());
~flat_tree();
// --------------------------------------------------------------------------
// Assignments.
//
// Assume that move assignment invalidates iterators and references.
flat_tree& operator=(const flat_tree&);
flat_tree& operator=(flat_tree&&);
// Takes the first if there are duplicates in the initializer list.
flat_tree& operator=(std::initializer_list<value_type> ilist);
// --------------------------------------------------------------------------
// Memory management.
//
// Beware that shrink_to_fit() simply forwards the request to the
// underlying_type and its implementation is free to optimize otherwise and
// leave capacity() to be greater that its size.
//
// reserve() and shrink_to_fit() invalidate iterators and references.
void reserve(size_type new_capacity);
size_type capacity() const;
void shrink_to_fit();
// --------------------------------------------------------------------------
// Size management.
//
// clear() leaves the capacity() of the flat_tree unchanged.
void clear();
size_type size() const;
size_type max_size() const;
bool empty() const;
// --------------------------------------------------------------------------
// Iterators.
iterator begin();
const_iterator begin() const;
const_iterator cbegin() const;
iterator end();
const_iterator end() const;
const_iterator cend() const;
reverse_iterator rbegin();
const_reverse_iterator rbegin() const;
const_reverse_iterator crbegin() const;
reverse_iterator rend();
const_reverse_iterator rend() const;
const_reverse_iterator crend() const;
// --------------------------------------------------------------------------
// Insert operations.
//
// Assume that every operation invalidates iterators and references.
// Insertion of one element can take O(size). Capacity of flat_tree grows in
// an implementation-defined manner.
//
// NOTE: Prefer to build a new flat_tree from a std::vector (or similar)
// instead of calling insert() repeatedly.
std::pair<iterator, bool> insert(const value_type& val);
std::pair<iterator, bool> insert(value_type&& val);
iterator insert(const_iterator position_hint, const value_type& x);
iterator insert(const_iterator position_hint, value_type&& x);
// This method inserts the values from the range [first, last) into the
// current tree. In case of KEEP_LAST_OF_DUPES newly added elements can
// overwrite existing values.
template <class InputIterator>
void insert(InputIterator first,
InputIterator last,
FlatContainerDupes dupes = KEEP_FIRST_OF_DUPES);
template <class... Args>
std::pair<iterator, bool> emplace(Args&&... args);
template <class... Args>
iterator emplace_hint(const_iterator position_hint, Args&&... args);
// --------------------------------------------------------------------------
// Erase operations.
//
// Assume that every operation invalidates iterators and references.
//
// erase(position), erase(first, last) can take O(size).
// erase(key) may take O(size) + O(log(size)).
//
// Prefer base::EraseIf() or some other variation on erase(remove(), end())
// idiom when deleting multiple non-consecutive elements.
iterator erase(iterator position);
iterator erase(const_iterator position);
iterator erase(const_iterator first, const_iterator last);
template <typename K>
size_type erase(const K& key);
// --------------------------------------------------------------------------
// Comparators.
key_compare key_comp() const;
value_compare value_comp() const;
// --------------------------------------------------------------------------
// Search operations.
//
// Search operations have O(log(size)) complexity.
template <typename K>
size_type count(const K& key) const;
template <typename K>
iterator find(const K& key);
template <typename K>
const_iterator find(const K& key) const;
template <typename K>
std::pair<iterator, iterator> equal_range(const K& key);
template <typename K>
std::pair<const_iterator, const_iterator> equal_range(const K& key) const;
template <typename K>
iterator lower_bound(const K& key);
template <typename K>
const_iterator lower_bound(const K& key) const;
template <typename K>
iterator upper_bound(const K& key);
template <typename K>
const_iterator upper_bound(const K& key) const;
// --------------------------------------------------------------------------
// General operations.
//
// Assume that swap invalidates iterators and references.
//
// Implementation note: currently we use operator==() and operator<() on
// std::vector, because they have the same contract we need, so we use them
// directly for brevity and in case it is more optimal than calling equal()
// and lexicograhpical_compare(). If the underlying container type is changed,
// this code may need to be modified.
void swap(flat_tree& other);
friend bool operator==(const flat_tree& lhs, const flat_tree& rhs) {
return lhs.impl_.body_ == rhs.impl_.body_;
}
friend bool operator!=(const flat_tree& lhs, const flat_tree& rhs) {
return !(lhs == rhs);
}
friend bool operator<(const flat_tree& lhs, const flat_tree& rhs) {
return lhs.impl_.body_ < rhs.impl_.body_;
}
friend bool operator>(const flat_tree& lhs, const flat_tree& rhs) {
return rhs < lhs;
}
friend bool operator>=(const flat_tree& lhs, const flat_tree& rhs) {
return !(lhs < rhs);
}
friend bool operator<=(const flat_tree& lhs, const flat_tree& rhs) {
return !(lhs > rhs);
}
friend void swap(flat_tree& lhs, flat_tree& rhs) { lhs.swap(rhs); }
protected:
// Emplaces a new item into the tree that is known not to be in it. This
// is for implementing map operator[].
template <class... Args>
iterator unsafe_emplace(const_iterator position, Args&&... args);
private:
// Helper class for e.g. lower_bound that can compare a value on the left
// to a key on the right.
struct KeyValueCompare {
// The key comparison object must outlive this class.
explicit KeyValueCompare(const key_compare& key_comp)
: key_comp_(key_comp) {}
template <typename T, typename U>
bool operator()(const T& lhs, const U& rhs) const {
return key_comp_(extract_if_value_type(lhs), extract_if_value_type(rhs));
}
private:
const key_type& extract_if_value_type(const value_type& v) const {
GetKeyFromValue extractor;
return extractor(v);
}
template <typename K>
const K& extract_if_value_type(const K& k) const {
return k;
}
const key_compare& key_comp_;
};
const flat_tree& as_const() { return *this; }
iterator const_cast_it(const_iterator c_it) {
auto distance = std::distance(cbegin(), c_it);
return std::next(begin(), distance);
}
// This method is inspired by both std::map::insert(P&&) and
// std::map::insert_or_assign(const K&, V&&). It inserts val if an equivalent
// element is not present yet, otherwise it overwrites. It returns an iterator
// to the modified element and a flag indicating whether insertion or
// assignment happened.
template <class V>
std::pair<iterator, bool> insert_or_assign(V&& val) {
auto position = lower_bound(GetKeyFromValue()(val));
if (position == end() || value_comp()(val, *position))
return {impl_.body_.emplace(position, std::forward<V>(val)), true};
*position = std::forward<V>(val);
return {position, false};
}
// This method is similar to insert_or_assign, with the following differences:
// - Instead of searching [begin(), end()) it only searches [first, last).
// - In case no equivalent element is found, val is appended to the end of the
// underlying body and an iterator to the next bigger element in [first,
// last) is returned.
template <class V>
std::pair<iterator, bool> append_or_assign(iterator first,
iterator last,
V&& val) {
auto position = std::lower_bound(first, last, val, value_comp());
if (position == last || value_comp()(val, *position)) {
// emplace_back might invalidate position, which is why distance needs to
// be cached.
const difference_type distance = std::distance(begin(), position);
impl_.body_.emplace_back(std::forward<V>(val));
return {std::next(begin(), distance), true};
}
*position = std::forward<V>(val);
return {position, false};
}
// This method is similar to insert, with the following differences:
// - Instead of searching [begin(), end()) it only searches [first, last).
// - In case no equivalent element is found, val is appended to the end of the
// underlying body and an iterator to the next bigger element in [first,
// last) is returned.
template <class V>
std::pair<iterator, bool> append_unique(iterator first,
iterator last,
V&& val) {
auto position = std::lower_bound(first, last, val, value_comp());
if (position == last || value_comp()(val, *position)) {
// emplace_back might invalidate position, which is why distance needs to
// be cached.
const difference_type distance = std::distance(begin(), position);
impl_.body_.emplace_back(std::forward<V>(val));
return {std::next(begin(), distance), true};
}
return {position, false};
}
void sort_and_unique(iterator first,
iterator last,
FlatContainerDupes dupes) {
// Preserve stability for the unique code below.
std::stable_sort(first, last, impl_.get_value_comp());
auto comparator = [this](const value_type& lhs, const value_type& rhs) {
// lhs is already <= rhs due to sort, therefore
// !(lhs < rhs) <=> lhs == rhs.
return !impl_.get_value_comp()(lhs, rhs);
};
iterator erase_after;
switch (dupes) {
case KEEP_FIRST_OF_DUPES:
erase_after = std::unique(first, last, comparator);
break;
case KEEP_LAST_OF_DUPES:
erase_after = LastUnique(first, last, comparator);
break;
}
erase(erase_after, last);
}
// To support comparators that may not be possible to default-construct, we
// have to store an instance of Compare. Using this to store all internal
// state of flat_tree and using private inheritance to store compare lets us
// take advantage of an empty base class optimization to avoid extra space in
// the common case when Compare has no state.
struct Impl : private value_compare {
Impl() = default;
template <class Cmp, class... Body>
explicit Impl(Cmp&& compare_arg, Body&&... underlying_type_args)
: value_compare(std::forward<Cmp>(compare_arg)),
body_(std::forward<Body>(underlying_type_args)...) {}
const value_compare& get_value_comp() const { return *this; }
const key_compare& get_key_comp() const { return *this; }
underlying_type body_;
} impl_;
// If the compare is not transparent we want to construct key_type once.
template <typename K>
using KeyTypeOrK = typename std::
conditional<IsTransparentCompare<key_compare>::value, K, key_type>::type;
};
// ----------------------------------------------------------------------------
// Lifetime.
template <class Key, class Value, class GetKeyFromValue, class KeyCompare>
flat_tree<Key, Value, GetKeyFromValue, KeyCompare>::flat_tree() = default;
template <class Key, class Value, class GetKeyFromValue, class KeyCompare>
flat_tree<Key, Value, GetKeyFromValue, KeyCompare>::flat_tree(
const KeyCompare& comp)
: impl_(comp) {}
template <class Key, class Value, class GetKeyFromValue, class KeyCompare>
template <class InputIterator>
flat_tree<Key, Value, GetKeyFromValue, KeyCompare>::flat_tree(
InputIterator first,
InputIterator last,
FlatContainerDupes dupe_handling,
const KeyCompare& comp)
: impl_(comp, first, last) {
sort_and_unique(begin(), end(), dupe_handling);
}
template <class Key, class Value, class GetKeyFromValue, class KeyCompare>
flat_tree<Key, Value, GetKeyFromValue, KeyCompare>::flat_tree(
const flat_tree&) = default;
template <class Key, class Value, class GetKeyFromValue, class KeyCompare>
flat_tree<Key, Value, GetKeyFromValue, KeyCompare>::flat_tree(flat_tree&&) =
default;
template <class Key, class Value, class GetKeyFromValue, class KeyCompare>
flat_tree<Key, Value, GetKeyFromValue, KeyCompare>::flat_tree(
std::vector<value_type> items,
FlatContainerDupes dupe_handling,
const KeyCompare& comp)
: impl_(comp, std::move(items)) {
sort_and_unique(begin(), end(), dupe_handling);
}
template <class Key, class Value, class GetKeyFromValue, class KeyCompare>
flat_tree<Key, Value, GetKeyFromValue, KeyCompare>::flat_tree(
std::initializer_list<value_type> ilist,
FlatContainerDupes dupe_handling,
const KeyCompare& comp)
: flat_tree(std::begin(ilist), std::end(ilist), dupe_handling, comp) {}
template <class Key, class Value, class GetKeyFromValue, class KeyCompare>
flat_tree<Key, Value, GetKeyFromValue, KeyCompare>::~flat_tree() = default;
// ----------------------------------------------------------------------------
// Assignments.
template <class Key, class Value, class GetKeyFromValue, class KeyCompare>
auto flat_tree<Key, Value, GetKeyFromValue, KeyCompare>::operator=(
const flat_tree&) -> flat_tree& = default;
template <class Key, class Value, class GetKeyFromValue, class KeyCompare>
auto flat_tree<Key, Value, GetKeyFromValue, KeyCompare>::operator=(flat_tree &&)
-> flat_tree& = default;
template <class Key, class Value, class GetKeyFromValue, class KeyCompare>
auto flat_tree<Key, Value, GetKeyFromValue, KeyCompare>::operator=(
std::initializer_list<value_type> ilist) -> flat_tree& {
impl_.body_ = ilist;
sort_and_unique(begin(), end(), KEEP_FIRST_OF_DUPES);
return *this;
}
// ----------------------------------------------------------------------------
// Memory management.
template <class Key, class Value, class GetKeyFromValue, class KeyCompare>
void flat_tree<Key, Value, GetKeyFromValue, KeyCompare>::reserve(
size_type new_capacity) {
impl_.body_.reserve(new_capacity);
}
template <class Key, class Value, class GetKeyFromValue, class KeyCompare>
auto flat_tree<Key, Value, GetKeyFromValue, KeyCompare>::capacity() const
-> size_type {
return impl_.body_.capacity();
}
template <class Key, class Value, class GetKeyFromValue, class KeyCompare>
void flat_tree<Key, Value, GetKeyFromValue, KeyCompare>::shrink_to_fit() {
impl_.body_.shrink_to_fit();
}
// ----------------------------------------------------------------------------
// Size management.
template <class Key, class Value, class GetKeyFromValue, class KeyCompare>
void flat_tree<Key, Value, GetKeyFromValue, KeyCompare>::clear() {
impl_.body_.clear();
}
template <class Key, class Value, class GetKeyFromValue, class KeyCompare>
auto flat_tree<Key, Value, GetKeyFromValue, KeyCompare>::size() const
-> size_type {
return impl_.body_.size();
}
template <class Key, class Value, class GetKeyFromValue, class KeyCompare>
auto flat_tree<Key, Value, GetKeyFromValue, KeyCompare>::max_size() const
-> size_type {
return impl_.body_.max_size();
}
template <class Key, class Value, class GetKeyFromValue, class KeyCompare>
bool flat_tree<Key, Value, GetKeyFromValue, KeyCompare>::empty() const {
return impl_.body_.empty();
}
// ----------------------------------------------------------------------------
// Iterators.
template <class Key, class Value, class GetKeyFromValue, class KeyCompare>
auto flat_tree<Key, Value, GetKeyFromValue, KeyCompare>::begin() -> iterator {
return impl_.body_.begin();
}
template <class Key, class Value, class GetKeyFromValue, class KeyCompare>
auto flat_tree<Key, Value, GetKeyFromValue, KeyCompare>::begin() const
-> const_iterator {
return impl_.body_.begin();
}
template <class Key, class Value, class GetKeyFromValue, class KeyCompare>
auto flat_tree<Key, Value, GetKeyFromValue, KeyCompare>::cbegin() const
-> const_iterator {
return impl_.body_.cbegin();
}
template <class Key, class Value, class GetKeyFromValue, class KeyCompare>
auto flat_tree<Key, Value, GetKeyFromValue, KeyCompare>::end() -> iterator {
return impl_.body_.end();
}
template <class Key, class Value, class GetKeyFromValue, class KeyCompare>
auto flat_tree<Key, Value, GetKeyFromValue, KeyCompare>::end() const
-> const_iterator {
return impl_.body_.end();
}
template <class Key, class Value, class GetKeyFromValue, class KeyCompare>
auto flat_tree<Key, Value, GetKeyFromValue, KeyCompare>::cend() const
-> const_iterator {
return impl_.body_.cend();
}
template <class Key, class Value, class GetKeyFromValue, class KeyCompare>
auto flat_tree<Key, Value, GetKeyFromValue, KeyCompare>::rbegin()
-> reverse_iterator {
return impl_.body_.rbegin();
}
template <class Key, class Value, class GetKeyFromValue, class KeyCompare>
auto flat_tree<Key, Value, GetKeyFromValue, KeyCompare>::rbegin() const
-> const_reverse_iterator {
return impl_.body_.rbegin();
}
template <class Key, class Value, class GetKeyFromValue, class KeyCompare>
auto flat_tree<Key, Value, GetKeyFromValue, KeyCompare>::crbegin() const
-> const_reverse_iterator {
return impl_.body_.crbegin();
}
template <class Key, class Value, class GetKeyFromValue, class KeyCompare>
auto flat_tree<Key, Value, GetKeyFromValue, KeyCompare>::rend()
-> reverse_iterator {
return impl_.body_.rend();
}
template <class Key, class Value, class GetKeyFromValue, class KeyCompare>
auto flat_tree<Key, Value, GetKeyFromValue, KeyCompare>::rend() const
-> const_reverse_iterator {
return impl_.body_.rend();
}
template <class Key, class Value, class GetKeyFromValue, class KeyCompare>
auto flat_tree<Key, Value, GetKeyFromValue, KeyCompare>::crend() const
-> const_reverse_iterator {
return impl_.body_.crend();
}
// ----------------------------------------------------------------------------
// Insert operations.
//
// Currently we use position_hint the same way as eastl or boost:
// https://github.com/electronicarts/EASTL/blob/master/include/EASTL/vector_set.h#L493
//
// We duplicate code between copy and move version so that we can avoid
// creating a temporary value.
template <class Key, class Value, class GetKeyFromValue, class KeyCompare>
auto flat_tree<Key, Value, GetKeyFromValue, KeyCompare>::insert(
const value_type& val) -> std::pair<iterator, bool> {
GetKeyFromValue extractor;
auto position = lower_bound(extractor(val));
if (position == end() || impl_.get_value_comp()(val, *position))
return {impl_.body_.insert(position, val), true};
return {position, false};
}
template <class Key, class Value, class GetKeyFromValue, class KeyCompare>
auto flat_tree<Key, Value, GetKeyFromValue, KeyCompare>::insert(
value_type&& val) -> std::pair<iterator, bool> {
GetKeyFromValue extractor;
auto position = lower_bound(extractor(val));
if (position == end() || impl_.get_value_comp()(val, *position))
return {impl_.body_.insert(position, std::move(val)), true};
return {position, false};
}
template <class Key, class Value, class GetKeyFromValue, class KeyCompare>
auto flat_tree<Key, Value, GetKeyFromValue, KeyCompare>::insert(
const_iterator position_hint,
const value_type& val) -> iterator {
if (position_hint == end() || impl_.get_value_comp()(val, *position_hint)) {
if (position_hint == begin() ||
impl_.get_value_comp()(*(position_hint - 1), val))
// We have to cast away const because of crbug.com/677044.
return impl_.body_.insert(const_cast_it(position_hint), val);
}
return insert(val).first;
}
template <class Key, class Value, class GetKeyFromValue, class KeyCompare>
auto flat_tree<Key, Value, GetKeyFromValue, KeyCompare>::insert(
const_iterator position_hint,
value_type&& val) -> iterator {
if (position_hint == end() || impl_.get_value_comp()(val, *position_hint)) {
if (position_hint == begin() ||
impl_.get_value_comp()(*(position_hint - 1), val))
// We have to cast away const because of crbug.com/677044.
return impl_.body_.insert(const_cast_it(position_hint), std::move(val));
}
return insert(std::move(val)).first;
}
template <class Key, class Value, class GetKeyFromValue, class KeyCompare>
template <class InputIterator>
void flat_tree<Key, Value, GetKeyFromValue, KeyCompare>::insert(
InputIterator first,
InputIterator last,
FlatContainerDupes dupes) {
if (first == last)
return;
// Cache results whether existing elements should be overwritten and whether
// inserting new elements happens immediately or will be done in a batch.
const bool overwrite_existing = dupes == KEEP_LAST_OF_DUPES;
const bool insert_inplace =
is_multipass<InputIterator>() && std::next(first) == last;
if (insert_inplace) {
if (overwrite_existing) {
for (; first != last; ++first)
insert_or_assign(*first);
} else
std::copy(first, last, std::inserter(*this, end()));
return;
}
// Provide a convenience lambda to obtain an iterator pointing past the last
// old element. This needs to be dymanic due to possible re-allocations.
const size_type original_size = size();
auto middle = [this, original_size]() {
return std::next(begin(), original_size);
};
// For batch updates initialize the first insertion point.
difference_type pos_first_new = original_size;
// Loop over the input range while appending new values and overwriting
// existing ones, if applicable. Keep track of the first insertion point.
if (overwrite_existing) {
for (; first != last; ++first) {
std::pair<iterator, bool> result =
append_or_assign(begin(), middle(), *first);
if (result.second) {
pos_first_new =
std::min(pos_first_new, std::distance(begin(), result.first));
}
}
} else {
for (; first != last; ++first) {
std::pair<iterator, bool> result =
append_unique(begin(), middle(), *first);
if (result.second) {
pos_first_new =
std::min(pos_first_new, std::distance(begin(), result.first));
}
}
}
// The new elements might be unordered and contain duplicates, so post-process
// the just inserted elements and merge them with the rest, inserting them at
// the previously found spot.
sort_and_unique(middle(), end(), dupes);
std::inplace_merge(std::next(begin(), pos_first_new), middle(), end(),
value_comp());
}
template <class Key, class Value, class GetKeyFromValue, class KeyCompare>
template <class... Args>
auto flat_tree<Key, Value, GetKeyFromValue, KeyCompare>::emplace(Args&&... args)
-> std::pair<iterator, bool> {
return insert(value_type(std::forward<Args>(args)...));
}
template <class Key, class Value, class GetKeyFromValue, class KeyCompare>
template <class... Args>
auto flat_tree<Key, Value, GetKeyFromValue, KeyCompare>::emplace_hint(
const_iterator position_hint,
Args&&... args) -> iterator {
return insert(position_hint, value_type(std::forward<Args>(args)...));
}
// ----------------------------------------------------------------------------
// Erase operations.
template <class Key, class Value, class GetKeyFromValue, class KeyCompare>
auto flat_tree<Key, Value, GetKeyFromValue, KeyCompare>::erase(
iterator position) -> iterator {
return impl_.body_.erase(position);
}
template <class Key, class Value, class GetKeyFromValue, class KeyCompare>
auto flat_tree<Key, Value, GetKeyFromValue, KeyCompare>::erase(
const_iterator position) -> iterator {
// We have to cast away const because of crbug.com/677044.
return erase(const_cast_it(position));
}
template <class Key, class Value, class GetKeyFromValue, class KeyCompare>
template <typename K>
auto flat_tree<Key, Value, GetKeyFromValue, KeyCompare>::erase(const K& val)
-> size_type {
auto eq_range = equal_range(val);
auto res = std::distance(eq_range.first, eq_range.second);
// We have to cast away const because of crbug.com/677044.
erase(const_cast_it(eq_range.first), const_cast_it(eq_range.second));
return res;
}
template <class Key, class Value, class GetKeyFromValue, class KeyCompare>
auto flat_tree<Key, Value, GetKeyFromValue, KeyCompare>::erase(
const_iterator first,
const_iterator last) -> iterator {
// We have to cast away const because of crbug.com/677044.
return impl_.body_.erase(const_cast_it(first), const_cast_it(last));
}
// ----------------------------------------------------------------------------
// Comparators.
template <class Key, class Value, class GetKeyFromValue, class KeyCompare>
auto flat_tree<Key, Value, GetKeyFromValue, KeyCompare>::key_comp() const
-> key_compare {
return impl_.get_key_comp();
}
template <class Key, class Value, class GetKeyFromValue, class KeyCompare>
auto flat_tree<Key, Value, GetKeyFromValue, KeyCompare>::value_comp() const
-> value_compare {
return impl_.get_value_comp();
}
// ----------------------------------------------------------------------------
// Search operations.
template <class Key, class Value, class GetKeyFromValue, class KeyCompare>
template <typename K>
auto flat_tree<Key, Value, GetKeyFromValue, KeyCompare>::count(
const K& key) const -> size_type {
auto eq_range = equal_range(key);
return std::distance(eq_range.first, eq_range.second);
}
template <class Key, class Value, class GetKeyFromValue, class KeyCompare>
template <typename K>
auto flat_tree<Key, Value, GetKeyFromValue, KeyCompare>::find(const K& key)
-> iterator {
return const_cast_it(as_const().find(key));
}
template <class Key, class Value, class GetKeyFromValue, class KeyCompare>
template <typename K>
auto flat_tree<Key, Value, GetKeyFromValue, KeyCompare>::find(
const K& key) const -> const_iterator {
auto eq_range = equal_range(key);
return (eq_range.first == eq_range.second) ? end() : eq_range.first;
}
template <class Key, class Value, class GetKeyFromValue, class KeyCompare>
template <typename K>
auto flat_tree<Key, Value, GetKeyFromValue, KeyCompare>::equal_range(
const K& key) -> std::pair<iterator, iterator> {
auto res = as_const().equal_range(key);
return {const_cast_it(res.first), const_cast_it(res.second)};
}
template <class Key, class Value, class GetKeyFromValue, class KeyCompare>
template <typename K>
auto flat_tree<Key, Value, GetKeyFromValue, KeyCompare>::equal_range(
const K& key) const -> std::pair<const_iterator, const_iterator> {
auto lower = lower_bound(key);
GetKeyFromValue extractor;
if (lower == end() || impl_.get_key_comp()(key, extractor(*lower)))
return {lower, lower};
return {lower, std::next(lower)};
}
template <class Key, class Value, class GetKeyFromValue, class KeyCompare>
template <typename K>
auto flat_tree<Key, Value, GetKeyFromValue, KeyCompare>::lower_bound(
const K& key) -> iterator {
return const_cast_it(as_const().lower_bound(key));
}
template <class Key, class Value, class GetKeyFromValue, class KeyCompare>
template <typename K>
auto flat_tree<Key, Value, GetKeyFromValue, KeyCompare>::lower_bound(
const K& key) const -> const_iterator {
static_assert(std::is_convertible<const KeyTypeOrK<K>&, const K&>::value,
"Requested type cannot be bound to the container's key_type "
"which is required for a non-transparent compare.");
const KeyTypeOrK<K>& key_ref = key;
KeyValueCompare key_value(impl_.get_key_comp());
return std::lower_bound(begin(), end(), key_ref, key_value);
}
template <class Key, class Value, class GetKeyFromValue, class KeyCompare>
template <typename K>
auto flat_tree<Key, Value, GetKeyFromValue, KeyCompare>::upper_bound(
const K& key) -> iterator {
return const_cast_it(as_const().upper_bound(key));
}
template <class Key, class Value, class GetKeyFromValue, class KeyCompare>
template <typename K>
auto flat_tree<Key, Value, GetKeyFromValue, KeyCompare>::upper_bound(
const K& key) const -> const_iterator {
static_assert(std::is_convertible<const KeyTypeOrK<K>&, const K&>::value,
"Requested type cannot be bound to the container's key_type "
"which is required for a non-transparent compare.");
const KeyTypeOrK<K>& key_ref = key;
KeyValueCompare key_value(impl_.get_key_comp());
return std::upper_bound(begin(), end(), key_ref, key_value);
}
// ----------------------------------------------------------------------------
// General operations.
template <class Key, class Value, class GetKeyFromValue, class KeyCompare>
void flat_tree<Key, Value, GetKeyFromValue, KeyCompare>::swap(
flat_tree& other) {
std::swap(impl_, other.impl_);
}
template <class Key, class Value, class GetKeyFromValue, class KeyCompare>
template <class... Args>
auto flat_tree<Key, Value, GetKeyFromValue, KeyCompare>::unsafe_emplace(
const_iterator position,
Args&&... args) -> iterator {
// We have to cast away const because of crbug.com/677044.
return impl_.body_.emplace(const_cast_it(position),
std::forward<Args>(args)...);
}
// For containers like sets, the key is the same as the value. This implements
// the GetKeyFromValue template parameter to flat_tree for this case.
template <class Key>
struct GetKeyFromValueIdentity {
const Key& operator()(const Key& k) const { return k; }
};
} // namespace internal
// ----------------------------------------------------------------------------
// Free functions.
// Erases all elements that match predicate. It has O(size) complexity.
template <class Key,
class Value,
class GetKeyFromValue,
class KeyCompare,
typename Predicate>
void EraseIf(base::internal::flat_tree<Key, Value, GetKeyFromValue, KeyCompare>&
container,
Predicate pred) {
container.erase(std::remove_if(container.begin(), container.end(), pred),
container.end());
}
} // namespace base
#endif // BASE_CONTAINERS_FLAT_TREE_H_