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/*
* include/framework/structure/BufferView.h
*
* Copyright (C) 2023 Douglas B. Rumbaugh <drumbaugh@psu.edu>
*
* Distributed under the Modified BSD License.
*
*/
#pragma once
#include <cstdlib>
#include <cassert>
#include <functional>
#include "psu-util/alignment.h"
#include "psu-ds/BloomFilter.h"
#include "framework/interface/Record.h"
namespace de {
typedef std::function<void(void*, size_t)> ReleaseFunction;
template <RecordInterface R>
class BufferView {
public:
BufferView() = default;
BufferView(const Wrapped<R> *buffer, size_t head, size_t tail, psudb::BloomFilter<R> *filter,
void *parent_buffer, ReleaseFunction release)
: m_buffer(buffer)
, m_release(release)
, m_parent_buffer(parent_buffer)
, m_head(head)
, m_tail(tail)
, m_tombstone_filter(filter) {}
~BufferView() {
m_release(m_parent_buffer, m_head);
}
bool check_tombstone(const R& rec) {
if (m_tombstone_filter && !m_tombstone_filter->lookup(rec)) return false;
for (size_t i=0; i<get_record_count(); i++) {
if (m_buffer[to_idx(i)].rec == rec && m_buffer[to_idx(i)].is_tombstone()) {
return true;
}
}
return false;
}
size_t get_record_count() {
return m_tail - m_head;
}
size_t get_tombstone_count() {
// FIXME: tombstone count
return 0;
}
Wrapped<R> *get(size_t i) {
assert(i < get_record_count());
return m_buffer + to_idx(i);
}
void copy_to_buffer(psudb::byte *buffer) {
memcpy(buffer, (std::byte*) (m_buffer + m_head), get_record_count() * sizeof(Wrapped<R>));
}
private:
const Wrapped<R>* m_buffer;
void *m_parent_buffer;
ReleaseFunction m_release;
size_t m_head;
size_t m_tail;
psudb::BloomFilter<R> *m_tombstone_filter;
size_t to_idx(size_t i) {
return (m_head + i) % m_buffer->get_capacity();
}
};
}
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