static void remove_from_heap(const RandomAccessIterator &first,
const RandomAccessIterator &item, const RandomAccessIterator &last,
const LessComparer &less_comparer)
{
assert(last > first);
assert(item >= first);
assert(item < last);
assert(is_heap(first, last, less_comparer));
typedef typename std::iterator_traits<RandomAccessIterator>::value_type
value_type;
const size_t new_heap_size = last - first - 1;
const size_t hole_index = item - first;
if (hole_index < new_heap_size) {
value_type tmp = std::move(first[new_heap_size]);
_move(first[new_heap_size], *item);
if (less_comparer(tmp, first[new_heap_size])) {
_sift_down(first, less_comparer, new_heap_size, hole_index, tmp);
}
else {
_sift_up(first, less_comparer, 0, hole_index, tmp);
}
}
assert(is_heap(first, last - 1, less_comparer));
}
void _heapify() {
int start = (_data.size() - 2) / 2;
while (start >= 0) {
_sift_down(start);
start--;
}
}
static void _pop_max_item(const RandomAccessIterator &first,
const LessComparer &less_comparer, const size_t heap_size)
{
assert(heap_size > 0);
typedef typename std::iterator_traits<RandomAccessIterator>::value_type
value_type;
value_type tmp = std::move(first[heap_size]);
_move(first[heap_size], first[0]);
_sift_down(first, less_comparer, heap_size, 0, tmp);
}
static void restore_heap_after_item_decrease(
const RandomAccessIterator &first, const RandomAccessIterator &item,
const RandomAccessIterator &last, const LessComparer &less_comparer)
{
assert(last > first);
assert(item >= first);
assert(item < last);
assert(is_heap(first, item, less_comparer));
typedef typename std::iterator_traits<RandomAccessIterator>::value_type
value_type;
const size_t heap_size = last - first;
const size_t hole_index = item - first;
value_type tmp = std::move(*item);
_sift_down(first, less_comparer, heap_size, hole_index, tmp);
assert(is_heap(first, last, less_comparer));
}
static void swap_max_item(const RandomAccessIterator &first,
const RandomAccessIterator &last,
typename std::iterator_traits<RandomAccessIterator>::value_type &item,
const LessComparer &less_comparer)
{
assert(first < last);
assert(is_heap(first, last, less_comparer));
typedef typename std::iterator_traits<RandomAccessIterator>::value_type
value_type;
const size_t heap_size = last - first;
value_type tmp = std::move(item);
_move(item, first[0]);
_sift_down(first, less_comparer, heap_size, 0, tmp);
assert(is_heap(first, last, less_comparer));
}
static void make_heap(const RandomAccessIterator &first,
const RandomAccessIterator &last, const LessComparer &less_comparer)
{
assert(last >= first);
typedef typename std::iterator_traits<RandomAccessIterator>::value_type
value_type;
const size_t heap_size = last - first;
if (heap_size > 1) {
// Skip leaf nodes without children. This is easy to do for non-paged
// heap, i.e. when page_chunks = 1, but it is difficult for paged heaps.
// So leaf nodes in paged heaps are visited anyway.
size_t i = (PageChunks == 1) ? ((heap_size - 2) / Fanout) :
(heap_size - 2);
do {
value_type item = std::move(first[i]);
_sift_down(first, less_comparer, heap_size, i, item);
} while (i-- > 0);
}
assert(is_heap(first, last, less_comparer));
}
