feat: add aos tuple sketch

Author: proost

tuple/CMakeLists.txt

@@ -54,4 +54,6 @@ install(FILES
 		include/array_tuple_intersection_impl.hpp
 		include/array_tuple_a_not_b.hpp
 		include/array_tuple_a_not_b_impl.hpp
+		include/array_of_strings_sketch.hpp
+		include/array_of_strings_sketch_impl.hpp
   DESTINATION "${CMAKE_INSTALL_INCLUDEDIR}/DataSketches")

tuple/include/array_of_strings_sketch.hpp

@@ -0,0 +1,150 @@
+/*
+ * 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 {
+
+// default update policy for an array of strings
+template<typename Allocator = std::allocator<std::string>>
+class default_array_of_strings_update_policy {
+public:
+  using array_of_strings = array<std::string, Allocator>;
+
+  explicit default_array_of_strings_update_policy(const Allocator& allocator = Allocator());
+
+  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;
+
+private:
+  Allocator allocator_;
+};
+
+// serializer/deserializer for an array of strings
+// Requirements: all strings must be valid UTF-8 and array size must be <= 127.
+template<typename Allocator = std::allocator<std::string>>
+struct array_of_strings_serde {
+  using array_of_strings = array<std::string, 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:
+  static void check_num_nodes(uint8_t num_nodes);
+  static uint32_t compute_total_bytes(const array_of_strings& item);
+  static void check_utf8(const std::string& value);
+};
+
+/**
+ * Extended class of compact_tuple_sketch for array of strings
+ * Requirements: all strings must be valid UTF-8 and array size must be <= 127.
+ */
+template<typename Allocator = std::allocator<std::string>>
+class compact_array_of_strings_tuple_sketch:
+  public compact_tuple_sketch<
+    array<std::string, Allocator>,
+    typename std::allocator_traits<Allocator>::template rebind_alloc<array<std::string, Allocator>>
+  > {
+public:
+  using array_of_strings = array<std::string, Allocator>;
+  using summary_allocator = typename std::allocator_traits<Allocator>::template rebind_alloc<array_of_strings>;
+  using Base = compact_tuple_sketch<array_of_strings, summary_allocator>;
+  using vector_bytes = typename Base::vector_bytes;
+
+  template<typename Sketch>
+  compact_array_of_strings_tuple_sketch(const Sketch& sketch, bool ordered = true);
+
+  void serialize(std::ostream& os) const;
+  vector_bytes serialize(unsigned header_size_bytes = 0) const;
+
+  static compact_array_of_strings_tuple_sketch deserialize(std::istream& is, uint64_t seed = DEFAULT_SEED,
+      const Allocator& allocator = Allocator());
+  static compact_array_of_strings_tuple_sketch deserialize(const void* bytes, size_t size, uint64_t seed = DEFAULT_SEED,
+      const Allocator& allocator = Allocator());
+
+private:
+  explicit compact_array_of_strings_tuple_sketch(Base&& base);
+};
+
+/**
+ * Extended class of update_tuple_sketch for array of strings
+ * Requirements: all strings must be valid UTF-8 and array size must be <= 127.
+ */
+template<typename Allocator = std::allocator<std::string>>
+class update_array_of_strings_tuple_sketch:
+  public update_tuple_sketch<
+    array<std::string, Allocator>,
+    array<std::string, Allocator>,
+    default_array_of_strings_update_policy<Allocator>,
+    typename std::allocator_traits<Allocator>::template rebind_alloc<array<std::string, Allocator>>
+  > {
+public:
+  using array_of_strings = array<std::string, Allocator>;
+  using summary_allocator = typename std::allocator_traits<Allocator>::template rebind_alloc<array_of_strings>;
+  using policy_type = default_array_of_strings_update_policy<Allocator>;
+  using Base = update_tuple_sketch<
+    array_of_strings,
+    array_of_strings,
+    policy_type,
+    summary_allocator
+  >;
+  using resize_factor = typename Base::resize_factor;
+  class builder;
+  using Base::update;
+
+  void update(const array_of_strings& key, const array_of_strings& value);
+  compact_array_of_strings_tuple_sketch<Allocator> compact(bool ordered = true) const;
+
+private:
+  update_array_of_strings_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_type& policy, const summary_allocator& allocator);
+
+  // Matches Java Util.PRIME for ArrayOfStrings key hashing.
+  static constexpr uint64_t STRING_ARR_HASH_SEED = 0x7A3CCA71ULL;
+
+  static uint64_t hash_key(const array_of_strings& key);
+};
+
+template<typename Allocator>
+class update_array_of_strings_tuple_sketch<Allocator>::builder:
+  public tuple_base_builder<builder, policy_type, summary_allocator> {
+public:
+  builder(const policy_type& policy = policy_type(), const summary_allocator& allocator = summary_allocator());
+
+  update_array_of_strings_tuple_sketch build() const;
+};
+
+} /* namespace datasketches */
+
+#include "array_of_strings_sketch_impl.hpp"
+
+#endif