array_of_strings_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_OF_STRINGS_SKETCH_HPP_
#define ARRAY_OF_STRINGS_SKETCH_HPP_
 
#include <memory>
#include <string>
 
#include "array_tuple_sketch.hpp"
#include "xxhash64.h"
 
namespace datasketches {
 
using array_of_strings = array<std::string>;
 
// default update policy for an array of strings
class default_array_of_strings_update_policy {
public:
  default_array_of_strings_update_policy() = default;
 
  array_of_strings create() const;
 
  void update(array_of_strings& array, const array_of_strings& input) const;
 
  void update(array_of_strings& array, const array_of_strings* input) const;
};
 
template<typename Allocator = std::allocator<array_of_strings>>
struct default_array_of_strings_serde {
  using summary_allocator = typename std::allocator_traits<Allocator>::template rebind_alloc<array_of_strings>;
 
  explicit default_array_of_strings_serde(const Allocator& allocator = Allocator());
 
  void serialize(std::ostream& os, const array_of_strings* items, unsigned num) const;
  void deserialize(std::istream& is, array_of_strings* items, unsigned num) const;
  size_t serialize(void* ptr, size_t capacity, const array_of_strings* items, unsigned num) const;
  size_t deserialize(const void* ptr, size_t capacity, array_of_strings* items, unsigned num) const;
  size_t size_of_item(const array_of_strings& item) const;
 
private:
  summary_allocator summary_allocator_;
  static void check_num_nodes(uint8_t num_nodes);
  static uint32_t compute_total_bytes(const array_of_strings& item);
};
 
uint64_t hash_array_of_strings_key(const array_of_strings& key);
 
template<typename Allocator = std::allocator<array_of_strings>>
class compact_array_of_strings_tuple_sketch:
  public compact_tuple_sketch<array_of_strings, Allocator> {
public:
  using Base = compact_tuple_sketch<array_of_strings, Allocator>;
  using vector_bytes = typename Base::vector_bytes;
  using Base::serialize;
 
  template<typename Sketch>
  compact_array_of_strings_tuple_sketch(const Sketch& sketch, bool ordered = true);
 
  template<typename SerDe = default_array_of_strings_serde<Allocator>>
  static compact_array_of_strings_tuple_sketch deserialize(std::istream& is, uint64_t seed = DEFAULT_SEED,
      const SerDe& sd = SerDe(), const Allocator& allocator = Allocator());
 
  template<typename SerDe = default_array_of_strings_serde<Allocator>>
  static compact_array_of_strings_tuple_sketch deserialize(const void* bytes, size_t size, uint64_t seed = DEFAULT_SEED,
      const SerDe& sd = SerDe(), const Allocator& allocator = Allocator());
 
private:
  explicit compact_array_of_strings_tuple_sketch(Base&& base);
};
 
template<typename Allocator = std::allocator<array_of_strings>,
         typename Policy = default_array_of_strings_update_policy>
using update_array_of_strings_tuple_sketch = update_tuple_sketch<
  array_of_strings,
  array_of_strings,
  Policy,
  Allocator
>;
 
template<typename Allocator = std::allocator<array_of_strings>, typename Policy = default_array_of_strings_update_policy>
compact_array_of_strings_tuple_sketch<Allocator> compact_array_of_strings_sketch(
  const update_array_of_strings_tuple_sketch<Allocator, Policy>& sketch, bool ordered = true);
 
} /* namespace datasketches */
 
#include "array_of_strings_sketch_impl.hpp"
 
#endif