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// Copyright 2021 The Tint Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#ifndef SRC_TINT_UTILS_UNIQUE_VECTOR_H_
#define SRC_TINT_UTILS_UNIQUE_VECTOR_H_
#include <cstddef>
#include <functional>
#include <unordered_set>
#include <utility>
#include <vector>
#include "src/tint/utils/hashset.h"
#include "src/tint/utils/vector.h"
namespace tint::utils {
/// UniqueVector is an ordered container that only contains unique items.
/// Attempting to add a duplicate is a no-op.
template <typename T, size_t N, typename HASH = std::hash<T>, typename EQUAL = std::equal_to<T>>
struct UniqueVector {
/// Constructor
UniqueVector() = default;
/// Constructor
/// @param v the vector to construct this UniqueVector with. Duplicate
/// elements will be removed.
explicit UniqueVector(std::vector<T>&& v) {
for (auto& el : v) {
Add(el);
}
}
/// add appends the item to the end of the vector, if the vector does not
/// already contain the given item.
/// @param item the item to append to the end of the vector
/// @returns true if the item was added, otherwise false.
bool Add(const T& item) {
if (set.Add(item)) {
vector.Push(item);
return true;
}
return false;
}
/// @returns true if the vector contains `item`
/// @param item the item
bool Contains(const T& item) const { return set.Contains(item); }
/// @param i the index of the element to retrieve
/// @returns the element at the index `i`
T& operator[](size_t i) { return vector[i]; }
/// @param i the index of the element to retrieve
/// @returns the element at the index `i`
const T& operator[](size_t i) const { return vector[i]; }
/// @returns true if the vector is empty
bool IsEmpty() const { return vector.IsEmpty(); }
/// @returns the number of items in the vector
size_t Length() const { return vector.Length(); }
/// @returns the pointer to the first element in the vector, or nullptr if the vector is empty.
const T* Data() const { return vector.IsEmpty() ? nullptr : &vector[0]; }
/// @returns an iterator to the beginning of the vector
auto begin() const { return vector.begin(); }
/// @returns an iterator to the end of the vector
auto end() const { return vector.end(); }
/// @returns an iterator to the beginning of the reversed vector
auto rbegin() const { return vector.rbegin(); }
/// @returns an iterator to the end of the reversed vector
auto rend() const { return vector.rend(); }
/// @returns a reference to the internal vector
operator VectorRef<T>() const { return vector; }
/// @returns the std::move()'d vector.
/// @note The UniqueVector must not be used after calling this method
VectorRef<T> Release() { return std::move(vector); }
/// Pre-allocates `count` elements in the vector and set
/// @param count the number of elements to pre-allocate
void Reserve(size_t count) {
vector.Reserve(count);
set.Reserve(count);
}
/// Removes the last element from the vector
/// @returns the popped element
T Pop() {
set.Remove(vector.Back());
return vector.Pop();
}
private:
Vector<T, N> vector;
Hashset<T, N, HASH, EQUAL> set;
};
} // namespace tint::utils
#endif // SRC_TINT_UTILS_UNIQUE_VECTOR_H_