File size: 5,325 Bytes
9c6594c |
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 |
// 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 <optional>
#include <string>
#include <variant>
#include "arrow/type.h"
#include "arrow/util/visibility.h"
namespace arrow {
/// \class ArrayStatistics
/// \brief Statistics for an Array
///
/// Apache Arrow format doesn't have statistics but data source such
/// as Apache Parquet may have statistics. Statistics associated with
/// data source can be read unified API via this class.
struct ARROW_EXPORT ArrayStatistics {
/// \brief The type for maximum and minimum values. If the target
/// value exists, one of them is used. `std::nullopt` is used
/// otherwise.
using ValueType = std::variant<bool, int64_t, uint64_t, double, std::string>;
static const std::shared_ptr<DataType>& ValueToArrowType(
const std::optional<ValueType>& value,
const std::shared_ptr<DataType>& array_type) {
if (!value.has_value()) {
return null();
}
struct Visitor {
const std::shared_ptr<DataType>& array_type;
const std::shared_ptr<DataType>& operator()(const bool&) { return boolean(); }
const std::shared_ptr<DataType>& operator()(const int64_t&) { return int64(); }
const std::shared_ptr<DataType>& operator()(const uint64_t&) { return uint64(); }
const std::shared_ptr<DataType>& operator()(const double&) { return float64(); }
const std::shared_ptr<DataType>& operator()(const std::string&) {
switch (array_type->id()) {
case Type::STRING:
case Type::BINARY:
case Type::FIXED_SIZE_BINARY:
case Type::LARGE_STRING:
case Type::LARGE_BINARY:
return array_type;
default:
return utf8();
}
}
} visitor{array_type};
return std::visit(visitor, value.value());
}
/// \brief The number of null values, may not be set
std::optional<int64_t> null_count = std::nullopt;
/// \brief The number of distinct values, may not be set
std::optional<int64_t> distinct_count = std::nullopt;
/// \brief The minimum value, may not be set
std::optional<ValueType> min = std::nullopt;
/// \brief Compute Arrow type of the minimum value.
///
/// If \ref ValueType is `std::string`, `array_type` may be
/// used. If `array_type` is a binary-like type such as \ref
/// arrow::binary and \ref arrow::large_utf8, `array_type` is
/// returned. \ref arrow::utf8 is returned otherwise.
///
/// If \ref ValueType isn't `std::string`, `array_type` isn't used.
///
/// \param array_type The Arrow type of the associated array.
///
/// \return \ref arrow::null if the minimum value is `std::nullopt`,
/// Arrow type based on \ref ValueType of the \ref min
/// otherwise.
const std::shared_ptr<DataType>& MinArrowType(
const std::shared_ptr<DataType>& array_type) {
return ValueToArrowType(min, array_type);
}
/// \brief Whether the minimum value is exact or not
bool is_min_exact = false;
/// \brief The maximum value, may not be set
std::optional<ValueType> max = std::nullopt;
/// \brief Compute Arrow type of the maximum value.
///
/// If \ref ValueType is `std::string`, `array_type` may be
/// used. If `array_type` is a binary-like type such as \ref
/// arrow::binary and \ref arrow::large_utf8, `array_type` is
/// returned. \ref arrow::utf8 is returned otherwise.
///
/// If \ref ValueType isn't `std::string`, `array_type` isn't used.
///
/// \param array_type The Arrow type of the associated array.
///
/// \return \ref arrow::null if the maximum value is `std::nullopt`,
/// Arrow type based on \ref ValueType of the \ref max
/// otherwise.
const std::shared_ptr<DataType>& MaxArrowType(
const std::shared_ptr<DataType>& array_type) {
return ValueToArrowType(max, array_type);
}
/// \brief Whether the maximum value is exact or not
bool is_max_exact = false;
/// \brief Check two statistics for equality
bool Equals(const ArrayStatistics& other) const {
return null_count == other.null_count && distinct_count == other.distinct_count &&
min == other.min && is_min_exact == other.is_min_exact && max == other.max &&
is_max_exact == other.is_max_exact;
}
/// \brief Check two statistics for equality
bool operator==(const ArrayStatistics& other) const { return Equals(other); }
/// \brief Check two statistics for not equality
bool operator!=(const ArrayStatistics& other) const { return !Equals(other); }
};
} // namespace arrow
|