array_tuple_sketch.hpp

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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 ARRAY_TUPLE_SKETCH_HPP_
#define ARRAY_TUPLE_SKETCH_HPP_
 
#include <vector>
#include <memory>
#include <type_traits>
#include <algorithm>
 
#include "serde.hpp"
#include "tuple_sketch.hpp"
 
namespace datasketches {
 
// This simple array is faster than std::vector and should be sufficient for this application
template<typename T, typename Allocator = std::allocator<T>>
class array {
public:
  using value_type = T;
  using allocator_type = Allocator;
  using alloc_traits = std::allocator_traits<Allocator>;
 
  explicit array(uint8_t size, const T& value, const Allocator& allocator = Allocator()):
  allocator_(allocator), size_(size), array_(allocator_.allocate(size_)) {
    init_values(value, std::is_trivially_copyable<T>());
  }
  array(const array& other):
    allocator_(other.allocator_),
    size_(other.size_),
    array_(allocator_.allocate(size_))
  {
    copy_from(other, std::is_trivially_copyable<T>());
  }
  array(array&& other) noexcept:
    allocator_(std::move(other.allocator_)),
    size_(other.size_),
    array_(other.array_)
  {
    other.array_ = nullptr;
    other.size_ = 0;
  }
  ~array() {
    if (array_ != nullptr) {
      destroy_values(std::is_trivially_destructible<T>());
      allocator_.deallocate(array_, size_);
    }
  }
  array& operator=(const array& other) {
    array copy(other);
    std::swap(allocator_, copy.allocator_);
    std::swap(size_, copy.size_);
    std::swap(array_, copy.array_);
    return *this;
  }
  array& operator=(array&& other) {
    std::swap(allocator_, other.allocator_);
    std::swap(size_, other.size_);
    std::swap(array_, other.array_);
    return *this;
  }
  T& operator[](size_t index) { return array_[index]; }
  T operator[](size_t index) const { return array_[index]; }
  uint8_t size() const { return size_; }
  T* data() { return array_; }
  const T* data() const { return array_; }
  bool operator==(const array& other) const {
    if (size_ != other.size_) return false;
    for (uint8_t i = 0; i < size_; ++i) if (array_[i] != other.array_[i]) return false;
    return true;
  }
private:
  void init_values(const T& value, std::true_type) {
    std::fill(array_, array_ + size_, value);
  }
  void init_values(const T& value, std::false_type) {
    for (uint8_t i = 0; i < size_; ++i) {
      alloc_traits::construct(allocator_, array_ + i, value);
    }
  }
  void copy_from(const array& other, std::true_type) {
    std::copy(other.array_, other.array_ + size_, array_);
  }
  void copy_from(const array& other, std::false_type) {
    for (uint8_t i = 0; i < size_; ++i) {
      alloc_traits::construct(allocator_, array_ + i, other.array_[i]);
    }
  }
  void destroy_values(std::true_type) {}
  void destroy_values(std::false_type) {
    for (uint8_t i = 0; i < size_; ++i) {
      alloc_traits::destroy(allocator_, array_ + i);
    }
  }
 
  Allocator allocator_;
  uint8_t size_;
  T* array_;
};
 
template<typename Array, typename Allocator = typename Array::allocator_type>
class default_array_tuple_update_policy {
public:
  default_array_tuple_update_policy(uint8_t num_values = 1, const Allocator& allocator = Allocator()):
    allocator_(allocator), num_values_(num_values) {}
  Array create() const {
    return Array(num_values_, 0, allocator_);
  }
  template<typename InputArray> // to allow any type with indexed access (such as double* or std::vector)
  void update(Array& array, const InputArray& update) const {
    for (uint8_t i = 0; i < num_values_; ++i) array[i] += update[i];
  }
  uint8_t get_num_values() const {
    return num_values_;
  }
 
private:
  Allocator allocator_;
  uint8_t num_values_;
};
 
// forward declaration
template<typename Array, typename Allocator> class compact_array_tuple_sketch;
 
template<
  typename Array,
  typename Policy = default_array_tuple_update_policy<Array>,
  typename Allocator = typename Array::allocator_type
>
class update_array_tuple_sketch: public update_tuple_sketch<Array, Array, Policy, Allocator> {
public:
  using Base = update_tuple_sketch<Array, Array, Policy, Allocator>;
  using resize_factor = typename Base::resize_factor;
 
  class builder;
 
  compact_array_tuple_sketch<Array, Allocator> compact(bool ordered = true) const;
 
  uint8_t get_num_values() const;
 
private:
  // for builder
  update_array_tuple_sketch(uint8_t lg_cur_size, uint8_t lg_nom_size, resize_factor rf, float p, uint64_t theta,
      uint64_t seed, const Policy& policy, const Allocator& allocator);
};
 
template<typename Array, typename Policy, typename Allocator>
class update_array_tuple_sketch<Array, Policy, Allocator>::builder: public tuple_base_builder<builder, Policy, Allocator> {
public:
  builder(const Policy& policy = Policy(), const Allocator& allocator = Allocator());
 
  update_array_tuple_sketch build() const;
};
 
template<
  typename Array,
  typename Allocator = typename Array::allocator_type
>
class compact_array_tuple_sketch: public compact_tuple_sketch<Array, Allocator> {
public:
  using Base = compact_tuple_sketch<Array, Allocator>;
  using Entry = typename Base::Entry;
  using AllocEntry = typename Base::AllocEntry;
  using AllocU64 = typename Base::AllocU64;
  using vector_bytes = typename Base::vector_bytes;
 
  static const uint8_t SERIAL_VERSION = 1;
  static const uint8_t SKETCH_FAMILY = 9;
  static const uint8_t SKETCH_TYPE = 3;
  enum flags { UNUSED1, UNUSED2, IS_EMPTY, HAS_ENTRIES, IS_ORDERED };
 
  template<typename Sketch>
  compact_array_tuple_sketch(const Sketch& other, bool ordered = true);
 
  uint8_t get_num_values() const;
 
  void serialize(std::ostream& os) const;
 
  vector_bytes serialize(unsigned header_size_bytes = 0) const;
 
  static compact_array_tuple_sketch deserialize(std::istream& is, uint64_t seed = DEFAULT_SEED, const Allocator& allocator = Allocator());
 
  static compact_array_tuple_sketch deserialize(const void* bytes, size_t size, uint64_t seed = DEFAULT_SEED,
      const Allocator& allocator = Allocator());
 
private:
  uint8_t num_values_;
 
  template<typename Ar, typename P, typename Al> friend class array_tuple_union;
  template<typename Ar, typename P, typename Al> friend class array_tuple_intersection;
  template<typename Ar, typename Al> friend class array_tuple_a_not_b;
  compact_array_tuple_sketch(bool is_empty, bool is_ordered, uint16_t seed_hash, uint64_t theta, std::vector<Entry, AllocEntry>&& entries, uint8_t num_values);
  compact_array_tuple_sketch(uint8_t num_values, Base&& base);
};
 
} /* namespace datasketches */
 
#include "array_tuple_sketch_impl.hpp"
 
#endif