paleolimbot commented on code in PR #45459: URL: https://github.com/apache/arrow/pull/45459#discussion_r1970112764
########## cpp/src/parquet/geometry_statistics.h: ########## @@ -0,0 +1,164 @@ +// 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. + +#pragma once + +#include <cstdint> +#include <memory> + +#include "parquet/platform.h" +#include "parquet/types.h" + +namespace parquet { + +/// \brief Structure represented encoded statistics to be written to and read from Parquet +/// serialized metadata. +/// +/// See the Parquet Thrift definition and GeospatialStatistics for the specific definition +/// of field values. +class PARQUET_EXPORT EncodedGeospatialStatistics { + public: + static constexpr double kInf = std::numeric_limits<double>::infinity(); + + EncodedGeospatialStatistics() = default; + EncodedGeospatialStatistics(const EncodedGeospatialStatistics&) = default; + EncodedGeospatialStatistics(EncodedGeospatialStatistics&&) = default; + EncodedGeospatialStatistics& operator=(const EncodedGeospatialStatistics&) = default; + + double xmin{kInf}; + double xmax{-kInf}; + double ymin{kInf}; + double ymax{-kInf}; + double zmin{kInf}; + double zmax{-kInf}; + double mmin{kInf}; + double mmax{-kInf}; + std::vector<int32_t> geospatial_types; + + bool has_z() const { return (zmax - zmin) != -kInf; } + + bool has_m() const { return (mmax - mmin) != -kInf; } + + bool is_set() const { return !geospatial_types.empty(); } +}; + +class GeospatialStatisticsImpl; + +/// \brief Base type for computing geospatial column statistics while writing a file +class PARQUET_EXPORT GeospatialStatistics { + public: + GeospatialStatistics(); + explicit GeospatialStatistics(std::unique_ptr<GeospatialStatisticsImpl> impl); + explicit GeospatialStatistics(const EncodedGeospatialStatistics& encoded); + GeospatialStatistics(GeospatialStatistics&&); + + ~GeospatialStatistics(); + + /// \brief Return true if bounds, geometry types, and validity are identical + bool Equals(const GeospatialStatistics& other) const; + + /// \brief Update these statistics based on previously calculated or decoded statistics + void Merge(const GeospatialStatistics& other); + + /// \brief Update these statistics based on values + void Update(const ByteArray* values, int64_t num_values, int64_t null_count); + + /// \brief Update these statistics based on the non-null elements of values + void UpdateSpaced(const ByteArray* values, const uint8_t* valid_bits, + int64_t valid_bits_offset, int64_t num_spaced_values, + int64_t num_values, int64_t null_count); + + /// \brief Update these statistics based on the non-null elements of values + /// + /// Currently, BinaryArray and LargeBinaryArray input is supported. + void Update(const ::arrow::Array& values); + + /// \brief Return these statistics to an empty state + void Reset(); + + /// \brief Encode the statistics for serializing to Thrift + /// + /// If invalid WKB was encountered, empty encoded statistics are returned + /// (such that is_set() returns false and they should not be written). + EncodedGeospatialStatistics Encode() const; + + /// \brief Returns true if all WKB encountered was valid or false otherwise + bool is_valid() const; + + std::shared_ptr<GeospatialStatistics> clone() const; + + /// \brief Update these statistics with previously generated statistics + void Decode(const EncodedGeospatialStatistics& encoded); + + /// \brief The minimum encountered value in the X dimension, or Inf if no X values were + /// encountered. + /// + /// The Parquet definition allows for "wrap around" bounds where xmin > xmax. In this + /// case, these bounds represent the union of the intervals [xmax, Inf] and [-Inf, + /// xmin]. This implementation does not yet generate these types of bounds but they may + /// be encountered in files written by other readers. + double GetXMin() const; Review Comment: I'm not sure! Because the zmin/zmax go together I think the code will always look like `if (stats.has_z()) ...`. The only case where X and Y are empty should be if no coordinates were encountered (e.g., all empty or null geometries), in which case the optional-ness of xmin, ymin, xmax, and ymax go together. If we think that `optional` is clearer for the individual values as well I'm happy to add that in! -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
