CPUHashmapBufferAccessor.hpp

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#pragma once

#include <assert.h>

#include <atomic>
#include <memory>
#include <vector>

#include "open3d/core/hashmap/HashmapBuffer.h"

namespace open3d {
namespace core {

class CPUHashmapBufferAccessor {
public:
    CPUHashmapBufferAccessor(int64_t capacity,
                             int64_t dsize_key,
                             int64_t dsize_value,
                             Tensor &keys,
                             Tensor &values,
                             Tensor &heap)
        : capacity_(capacity),
          dsize_key_(dsize_key),
          dsize_value_(dsize_value),
          keys_(keys.GetDataPtr<uint8_t>()),
          values_(values.GetDataPtr<uint8_t>()),
          heap_(static_cast<addr_t *>(heap.GetDataPtr())) {
        std::memset(values_, 0, capacity_ * dsize_value_);
    }

    void Reset() {
#pragma omp parallel for
        for (int i = 0; i < capacity_; ++i) {
            heap_[i] = i;
        }

        heap_counter_ = 0;
    }

    addr_t DeviceAllocate() { return heap_[heap_counter_.fetch_add(1)]; }

    void DeviceFree(addr_t ptr) { heap_[heap_counter_.fetch_sub(1) - 1] = ptr; }

    int HeapCounter() const { return heap_counter_.load(); }

    std::pair<void *, void *> ExtractIterator(addr_t ptr) {
        return std::make_pair(keys_ + ptr * dsize_key_,
                              values_ + ptr * dsize_value_);
    }

public:
    int64_t capacity_;
    int64_t dsize_key_;
    int64_t dsize_value_;

    uint8_t *keys_;                 /* [N] * sizeof(Key) */
    uint8_t *values_;               /* [N] * sizeof(Value) */
    addr_t *heap_;                  /* [N] */
    std::atomic<int> heap_counter_; /* [1] */
};

}  // namespace core
}  // namespace open3d