#pragma once
namespace WTF {
template<typename T>
class Insertion {
public:
Insertion() { }
template<typename U>
Insertion(size_t index, U&& element)
: m_index(index)
, m_element(std::forward<U>(element))
{
}
size_t index() const { return m_index; }
const T& element() const { return m_element; }
T& element() { return m_element; }
bool operator<(const Insertion& other) const
{
return m_index < other.m_index;
}
private:
size_t m_index { 0 };
T m_element { };
};
template<typename TargetVectorType, typename InsertionVectorType>
size_t executeInsertions(TargetVectorType& target, InsertionVectorType& insertions)
{
size_t numInsertions = insertions.size();
if (!numInsertions)
return 0;
size_t originalTargetSize = target.size();
target.grow(target.size() + numInsertions);
size_t lastIndex = target.size();
for (size_t indexInInsertions = numInsertions; indexInInsertions--;) {
ASSERT(!indexInInsertions || insertions[indexInInsertions].index() >= insertions[indexInInsertions - 1].index());
ASSERT_UNUSED(originalTargetSize, insertions[indexInInsertions].index() <= originalTargetSize);
size_t firstIndex = insertions[indexInInsertions].index() + indexInInsertions;
size_t indexOffset = indexInInsertions + 1;
for (size_t i = lastIndex; --i > firstIndex;)
target[i] = WTFMove(target[i - indexOffset]);
target[firstIndex] = WTFMove(insertions[indexInInsertions].element());
lastIndex = firstIndex;
}
insertions.shrink(0);
return numInsertions;
}
}
using WTF::Insertion;
using WTF::executeInsertions;