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#### Created: 2025-08-26 07:03

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    /Users/andrewlamb/Software/arrow-rs/arrow-schema/src/datatype.rs

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    // Licensed to the Apache Software Foundation (ASF) under one
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    // or more contributor license agreements.  See the NOTICE file
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    // distributed with this work for additional information
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    // regarding copyright ownership.  The ASF licenses this file
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    // to you under the Apache License, Version 2.0 (the
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    // "License"); you may not use this file except in compliance
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    // with the License.  You may obtain a copy of the License at
    8
    //
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    //   http://www.apache.org/licenses/LICENSE-2.0
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    //
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    // Unless required by applicable law or agreed to in writing,
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    // software distributed under the License is distributed on an
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    // "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
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    // KIND, either express or implied.  See the License for the
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    // specific language governing permissions and limitations
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    // under the License.
    17
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    use std::fmt;
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    use std::str::FromStr;
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    use std::sync::Arc;
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    use crate::{ArrowError, Field, FieldRef, Fields, UnionFields};
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    /// Datatypes supported by this implementation of Apache Arrow.
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    ///
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    /// The variants of this enum include primitive fixed size types as well as
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    /// parametric or nested types. See [`Schema.fbs`] for Arrow's specification.
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    ///
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    /// # Examples
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    ///
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    /// Primitive types
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    /// ```
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    /// # use arrow_schema::DataType;
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    /// // create a new 32-bit signed integer
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    /// let data_type = DataType::Int32;
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    /// ```
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    ///
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    /// Nested Types
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    /// ```
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    /// # use arrow_schema::{DataType, Field};
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    /// # use std::sync::Arc;
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    /// // create a new list of 32-bit signed integers directly
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    /// let list_data_type = DataType::List(Arc::new(Field::new_list_field(DataType::Int32, true)));
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    /// // Create the same list type with constructor
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    /// let list_data_type2 = DataType::new_list(DataType::Int32, true);
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    /// assert_eq!(list_data_type, list_data_type2);
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    /// ```
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    ///
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    /// Dictionary Types
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    /// ```
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    /// # use arrow_schema::{DataType};
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    /// // String Dictionary (key type Int32 and value type Utf8)
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    /// let data_type = DataType::Dictionary(Box::new(DataType::Int32), Box::new(DataType::Utf8));
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    /// ```
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    ///
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    /// Timestamp Types
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    /// ```
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    /// # use arrow_schema::{DataType, TimeUnit};
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    /// // timestamp with millisecond precision without timezone specified
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    /// let data_type = DataType::Timestamp(TimeUnit::Millisecond, None);
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    /// // timestamp with nanosecond precision in UTC timezone
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    /// let data_type = DataType::Timestamp(TimeUnit::Nanosecond, Some("UTC".into()));
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    ///```
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    ///
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    /// # Display and FromStr
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    ///
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    /// The `Display` and `FromStr` implementations for `DataType` are
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    /// human-readable, parseable, and reversible.
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    ///
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    /// ```
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    /// # use arrow_schema::DataType;
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    /// let data_type = DataType::Dictionary(Box::new(DataType::Int32), Box::new(DataType::Utf8));
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    /// let data_type_string = data_type.to_string();
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    /// assert_eq!(data_type_string, "Dictionary(Int32, Utf8)");
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    /// // display can be parsed back into the original type
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    /// let parsed_data_type: DataType = data_type.to_string().parse().unwrap();
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    /// assert_eq!(data_type, parsed_data_type);
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    /// ```
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    ///
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    /// # Nested Support
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    /// Currently, the Rust implementation supports the following nested types:
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    ///  - `List<T>`
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    ///  - `LargeList<T>`
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    ///  - `FixedSizeList<T>`
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    ///  - `Struct<T, U, V, ...>`
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    ///  - `Union<T, U, V, ...>`
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    ///  - `Map<K, V>`
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    ///
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    /// Nested types can themselves be nested within other arrays.
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    /// For more information on these types please see
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    /// [the physical memory layout of Apache Arrow]
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    ///
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    /// [`Schema.fbs`]: https://github.com/apache/arrow/blob/main/format/Schema.fbs
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    /// [the physical memory layout of Apache Arrow]: https://arrow.apache.org/docs/format/Columnar.html#physical-memory-layout
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    #[derive(Debug, Clone, PartialEq, Eq, Hash, PartialOrd, Ord)]
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    #[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
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    pub enum DataType {
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        /// Null type
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        Null,
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        /// A boolean datatype representing the values `true` and `false`.
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        Boolean,
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        /// A signed 8-bit integer.
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        Int8,
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        /// A signed 16-bit integer.
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        Int16,
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        /// A signed 32-bit integer.
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        Int32,
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        /// A signed 64-bit integer.
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        Int64,
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        /// An unsigned 8-bit integer.
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        UInt8,
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        /// An unsigned 16-bit integer.
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        UInt16,
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        /// An unsigned 32-bit integer.
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        UInt32,
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        /// An unsigned 64-bit integer.
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        UInt64,
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        /// A 16-bit floating point number.
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        Float16,
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        /// A 32-bit floating point number.
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        Float32,
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        /// A 64-bit floating point number.
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        Float64,
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        /// A timestamp with an optional timezone.
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        ///
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        /// Time is measured as a Unix epoch, counting the seconds from
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        /// 00:00:00.000 on 1 January 1970, excluding leap seconds,
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        /// as a signed 64-bit integer.
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        ///
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        /// The time zone is a string indicating the name of a time zone, one of:
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        ///
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        /// * As used in the Olson time zone database (the "tz database" or
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        ///   "tzdata"), such as "America/New_York"
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        /// * An absolute time zone offset of the form +XX:XX or -XX:XX, such as +07:30
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        ///
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        /// Timestamps with a non-empty timezone
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        /// ------------------------------------
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        ///
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        /// If a Timestamp column has a non-empty timezone value, its epoch is
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        /// 1970-01-01 00:00:00 (January 1st 1970, midnight) in the *UTC* timezone
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        /// (the Unix epoch), regardless of the Timestamp's own timezone.
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        ///
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        /// Therefore, timestamp values with a non-empty timezone correspond to
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        /// physical points in time together with some additional information about
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        /// how the data was obtained and/or how to display it (the timezone).
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        ///
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        ///   For example, the timestamp value 0 with the timezone string "Europe/Paris"
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        ///   corresponds to "January 1st 1970, 00h00" in the UTC timezone, but the
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        ///   application may prefer to display it as "January 1st 1970, 01h00" in
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        ///   the Europe/Paris timezone (which is the same physical point in time).
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        ///
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        /// One consequence is that timestamp values with a non-empty timezone
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        /// can be compared and ordered directly, since they all share the same
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        /// well-known point of reference (the Unix epoch).
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        ///
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        /// Timestamps with an unset / empty timezone
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        /// -----------------------------------------
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        ///
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        /// If a Timestamp column has no timezone value, its epoch is
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        /// 1970-01-01 00:00:00 (January 1st 1970, midnight) in an *unknown* timezone.
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        ///
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        /// Therefore, timestamp values without a timezone cannot be meaningfully
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        /// interpreted as physical points in time, but only as calendar / clock
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        /// indications ("wall clock time") in an unspecified timezone.
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        ///
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        ///   For example, the timestamp value 0 with an empty timezone string
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        ///   corresponds to "January 1st 1970, 00h00" in an unknown timezone: there
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        ///   is not enough information to interpret it as a well-defined physical
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        ///   point in time.
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        ///
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        /// One consequence is that timestamp values without a timezone cannot
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        /// be reliably compared or ordered, since they may have different points of
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        /// reference.  In particular, it is *not* possible to interpret an unset
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        /// or empty timezone as the same as "UTC".
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        ///
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        /// Conversion between timezones
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        /// ----------------------------
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        ///
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        /// If a Timestamp column has a non-empty timezone, changing the timezone
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        /// to a different non-empty value is a metadata-only operation:
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        /// the timestamp values need not change as their point of reference remains
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        /// the same (the Unix epoch).
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        ///
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        /// However, if a Timestamp column has no timezone value, changing it to a
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        /// non-empty value requires to think about the desired semantics.
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        /// One possibility is to assume that the original timestamp values are
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        /// relative to the epoch of the timezone being set; timestamp values should
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        /// then adjusted to the Unix epoch (for example, changing the timezone from
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        /// empty to "Europe/Paris" would require converting the timestamp values
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        /// from "Europe/Paris" to "UTC", which seems counter-intuitive but is
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        /// nevertheless correct).
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        ///
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        /// ```
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        /// # use arrow_schema::{DataType, TimeUnit};
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        /// DataType::Timestamp(TimeUnit::Second, None);
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        /// DataType::Timestamp(TimeUnit::Second, Some("literal".into()));
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        /// DataType::Timestamp(TimeUnit::Second, Some("string".to_string().into()));
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        /// ```
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        ///
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        /// # Timezone representation
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        /// ----------------------------
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        /// It is possible to use either the timezone string representation, such as "UTC", or the absolute time zone offset "+00:00".
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        /// For timezones with fixed offsets, such as "UTC" or "JST", the offset representation is recommended, as it is more explicit and less ambiguous.
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        ///
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        /// Most arrow-rs functionalities use the absolute offset representation,
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        /// such as [`PrimitiveArray::with_timezone_utc`] that applies a
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        /// UTC timezone to timestamp arrays.
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        ///
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        /// [`PrimitiveArray::with_timezone_utc`]: https://docs.rs/arrow/latest/arrow/array/struct.PrimitiveArray.html#method.with_timezone_utc
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        ///
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        /// Timezone string parsing
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        /// -----------------------
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        /// When feature `chrono-tz` is not enabled, allowed timezone strings are fixed offsets of the form "+09:00", "-09" or "+0930".
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        ///
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        /// When feature `chrono-tz` is enabled, additional strings supported by [chrono_tz](https://docs.rs/chrono-tz/latest/chrono_tz/)
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        /// are also allowed, which include [IANA database](https://en.wikipedia.org/wiki/List_of_tz_database_time_zones)
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        /// timezones.
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        Timestamp(TimeUnit, Option<Arc<str>>),
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        /// A signed 32-bit date representing the elapsed time since UNIX epoch (1970-01-01)
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        /// in days.
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        Date32,
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        /// A signed 64-bit date representing the elapsed time since UNIX epoch (1970-01-01)
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        /// in milliseconds.
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        ///
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        /// # Valid Ranges
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        ///
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        /// According to the Arrow specification ([Schema.fbs]), values of Date64
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        /// are treated as the number of *days*, in milliseconds, since the UNIX
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        /// epoch. Therefore, values of this type  must be evenly divisible by
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        /// `86_400_000`, the number of milliseconds in a standard day.
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        ///
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        /// It is not valid to store milliseconds that do not represent an exact
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        /// day. The reason for this restriction is compatibility with other
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        /// language's native libraries (specifically Java), which historically
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        /// lacked a dedicated date type and only supported timestamps.
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        ///
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        /// # Validation
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        ///
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        /// This library does not validate or enforce that Date64 values are evenly
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        /// divisible by `86_400_000`  for performance and usability reasons. Date64
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        /// values are treated similarly to `Timestamp(TimeUnit::Millisecond,
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        /// None)`: values will be displayed with a time of day if the value does
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        /// not represent an exact day, and arithmetic will be done at the
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        /// millisecond granularity.
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        ///
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        /// # Recommendation
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        ///
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        /// Users should prefer [`Date32`] to cleanly represent the number
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        /// of days, or one of the Timestamp variants to include time as part of the
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        /// representation, depending on their use case.
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        ///
    252
        /// # Further Reading
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        ///
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        /// For more details, see [#5288](https://github.com/apache/arrow-rs/issues/5288).
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        ///
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        /// [`Date32`]: Self::Date32
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        /// [Schema.fbs]: https://github.com/apache/arrow/blob/main/format/Schema.fbs
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        Date64,
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        /// A signed 32-bit time representing the elapsed time since midnight in the unit of `TimeUnit`.
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        /// Must be either seconds or milliseconds.
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        Time32(TimeUnit),
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        /// A signed 64-bit time representing the elapsed time since midnight in the unit of `TimeUnit`.
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        /// Must be either microseconds or nanoseconds.
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        Time64(TimeUnit),
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        /// Measure of elapsed time in either seconds, milliseconds, microseconds or nanoseconds.
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        Duration(TimeUnit),
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        /// A "calendar" interval which models types that don't necessarily
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        /// have a precise duration without the context of a base timestamp (e.g.
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        /// days can differ in length during day light savings time transitions).
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        Interval(IntervalUnit),
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        /// Opaque binary data of variable length.
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        ///
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        /// A single Binary array can store up to [`i32::MAX`] bytes
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        /// of binary data in total.
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        Binary,
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        /// Opaque binary data of fixed size.
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        /// Enum parameter specifies the number of bytes per value.
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        FixedSizeBinary(i32),
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        /// Opaque binary data of variable length and 64-bit offsets.
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        ///
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        /// A single LargeBinary array can store up to [`i64::MAX`] bytes
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        /// of binary data in total.
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        LargeBinary,
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        /// Opaque binary data of variable length.
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        ///
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        /// Logically the same as [`Binary`], but the internal representation uses a view
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        /// struct that contains the string length and either the string's entire data
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        /// inline (for small strings) or an inlined prefix, an index of another buffer,
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        /// and an offset pointing to a slice in that buffer (for non-small strings).
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        ///
    291
        /// [`Binary`]: Self::Binary
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        BinaryView,
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        /// A variable-length string in Unicode with UTF-8 encoding.
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        ///
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        /// A single Utf8 array can store up to [`i32::MAX`] bytes
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        /// of string data in total.
    297
        Utf8,
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        /// A variable-length string in Unicode with UFT-8 encoding and 64-bit offsets.
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        ///
    300
        /// A single LargeUtf8 array can store up to [`i64::MAX`] bytes
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        /// of string data in total.
    302
        LargeUtf8,
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        /// A variable-length string in Unicode with UTF-8 encoding
    304
        ///
    305
        /// Logically the same as [`Utf8`], but the internal representation uses a view
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        /// struct that contains the string length and either the string's entire data
    307
        /// inline (for small strings) or an inlined prefix, an index of another buffer,
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        /// and an offset pointing to a slice in that buffer (for non-small strings).
    309
        ///
    310
        /// [`Utf8`]: Self::Utf8
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        Utf8View,
    312
        /// A list of some logical data type with variable length.
    313
        ///
    314
        /// A single List array can store up to [`i32::MAX`] elements in total.
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        List(FieldRef),
    316
    317
        /// (NOT YET FULLY SUPPORTED)  A list of some logical data type with variable length.
    318
        ///
    319
        /// Logically the same as [`List`], but the internal representation differs in how child
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        /// data is referenced, allowing flexibility in how data is layed out.
    321
        ///
    322
        /// Note this data type is not yet fully supported. Using it with arrow APIs may result in `panic`s.
    323
        ///
    324
        /// [`List`]: Self::List
    325
        ListView(FieldRef),
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        /// A list of some logical data type with fixed length.
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        FixedSizeList(FieldRef, i32),
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        /// A list of some logical data type with variable length and 64-bit offsets.
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        ///
    330
        /// A single LargeList array can store up to [`i64::MAX`] elements in total.
    331
        LargeList(FieldRef),
    332
    333
        /// (NOT YET FULLY SUPPORTED)  A list of some logical data type with variable length and 64-bit offsets.
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        ///
    335
        /// Logically the same as [`LargeList`], but the internal representation differs in how child
    336
        /// data is referenced, allowing flexibility in how data is layed out.
    337
        ///
    338
        /// Note this data type is not yet fully supported. Using it with arrow APIs may result in `panic`s.
    339
        ///
    340
        /// [`LargeList`]: Self::LargeList
    341
        LargeListView(FieldRef),
    342
        /// A nested datatype that contains a number of sub-fields.
    343
        Struct(Fields),
    344
        /// A nested datatype that can represent slots of differing types. Components:
    345
        ///
    346
        /// 1. [`UnionFields`]
    347
        /// 2. The type of union (Sparse or Dense)
    348
        Union(UnionFields, UnionMode),
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        /// A dictionary encoded array (`key_type`, `value_type`), where
    350
        /// each array element is an index of `key_type` into an
    351
        /// associated dictionary of `value_type`.
    352
        ///
    353
        /// Dictionary arrays are used to store columns of `value_type`
    354
        /// that contain many repeated values using less memory, but with
    355
        /// a higher CPU overhead for some operations.
    356
        ///
    357
        /// This type mostly used to represent low cardinality string
    358
        /// arrays or a limited set of primitive types as integers.
    359
        Dictionary(Box<DataType>, Box<DataType>),
    360
        /// Exact 32-bit width decimal value with precision and scale
    361
        ///
    362
        /// * precision is the total number of digits
    363
        /// * scale is the number of digits past the decimal
    364
        ///
    365
        /// For example the number 123.45 has precision 5 and scale 2.
    366
        ///
    367
        /// In certain situations, scale could be negative number. For
    368
        /// negative scale, it is the number of padding 0 to the right
    369
        /// of the digits.
    370
        ///
    371
        /// For example the number 12300 could be treated as a decimal
    372
        /// has precision 3 and scale -2.
    373
        Decimal32(u8, i8),
    374
        /// Exact 64-bit width decimal value with precision and scale
    375
        ///
    376
        /// * precision is the total number of digits
    377
        /// * scale is the number of digits past the decimal
    378
        ///
    379
        /// For example the number 123.45 has precision 5 and scale 2.
    380
        ///
    381
        /// In certain situations, scale could be negative number. For
    382
        /// negative scale, it is the number of padding 0 to the right
    383
        /// of the digits.
    384
        ///
    385
        /// For example the number 12300 could be treated as a decimal
    386
        /// has precision 3 and scale -2.
    387
        Decimal64(u8, i8),
    388
        /// Exact 128-bit width decimal value with precision and scale
    389
        ///
    390
        /// * precision is the total number of digits
    391
        /// * scale is the number of digits past the decimal
    392
        ///
    393
        /// For example the number 123.45 has precision 5 and scale 2.
    394
        ///
    395
        /// In certain situations, scale could be negative number. For
    396
        /// negative scale, it is the number of padding 0 to the right
    397
        /// of the digits.
    398
        ///
    399
        /// For example the number 12300 could be treated as a decimal
    400
        /// has precision 3 and scale -2.
    401
        Decimal128(u8, i8),
    402
        /// Exact 256-bit width decimal value with precision and scale
    403
        ///
    404
        /// * precision is the total number of digits
    405
        /// * scale is the number of digits past the decimal
    406
        ///
    407
        /// For example the number 123.45 has precision 5 and scale 2.
    408
        ///
    409
        /// In certain situations, scale could be negative number. For
    410
        /// negative scale, it is the number of padding 0 to the right
    411
        /// of the digits.
    412
        ///
    413
        /// For example the number 12300 could be treated as a decimal
    414
        /// has precision 3 and scale -2.
    415
        Decimal256(u8, i8),
    416
        /// A Map is a logical nested type that is represented as
    417
        ///
    418
        /// `List<entries: Struct<key: K, value: V>>`
    419
        ///
    420
        /// The keys and values are each respectively contiguous.
    421
        /// The key and value types are not constrained, but keys should be
    422
        /// hashable and unique.
    423
        /// Whether the keys are sorted can be set in the `bool` after the `Field`.
    424
        ///
    425
        /// In a field with Map type, the field has a child Struct field, which then
    426
        /// has two children: key type and the second the value type. The names of the
    427
        /// child fields may be respectively "entries", "key", and "value", but this is
    428
        /// not enforced.
    429
        Map(FieldRef, bool),
    430
        /// A run-end encoding (REE) is a variation of run-length encoding (RLE). These
    431
        /// encodings are well-suited for representing data containing sequences of the
    432
        /// same value, called runs. Each run is represented as a value and an integer giving
    433
        /// the index in the array where the run ends.
    434
        ///
    435
        /// A run-end encoded array has no buffers by itself, but has two child arrays. The
    436
        /// first child array, called the run ends array, holds either 16, 32, or 64-bit
    437
        /// signed integers. The actual values of each run are held in the second child array.
    438
        ///
    439
        /// These child arrays are prescribed the standard names of "run_ends" and "values"
    440
        /// respectively.
    441
        RunEndEncoded(FieldRef, FieldRef),
    442
    }
    443
    444
    /// An absolute length of time in seconds, milliseconds, microseconds or nanoseconds.
    445
    #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash, PartialOrd, Ord)]
    446
    #[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
    447
    pub enum TimeUnit {
    448
        /// Time in seconds.
    449
        Second,
    450
        /// Time in milliseconds.
    451
        Millisecond,
    452
        /// Time in microseconds.
    453
        Microsecond,
    454
        /// Time in nanoseconds.
    455
        Nanosecond,
    456
    }
    457
    458
    /// YEAR_MONTH, DAY_TIME, MONTH_DAY_NANO interval in SQL style.
    459
    #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash, PartialOrd, Ord)]
    460
    #[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
    461
    pub enum IntervalUnit {
    462
        /// Indicates the number of elapsed whole months, stored as 4-byte integers.
    463
        YearMonth,
    464
        /// Indicates the number of elapsed days and milliseconds,
    465
        /// stored as 2 contiguous 32-bit integers (days, milliseconds) (8-bytes in total).
    466
        DayTime,
    467
        /// A triple of the number of elapsed months, days, and nanoseconds.
    468
        /// The values are stored contiguously in 16 byte blocks. Months and
    469
        /// days are encoded as 32 bit integers and nanoseconds is encoded as a
    470
        /// 64 bit integer. All integers are signed. Each field is independent
    471
        /// (e.g. there is no constraint that nanoseconds have the same sign
    472
        /// as days or that the quantity of nanoseconds represents less
    473
        /// than a day's worth of time).
    474
        MonthDayNano,
    475
    }
    476
    477
    /// Sparse or Dense union layouts
    478
    #[derive(Debug, Clone, PartialEq, Eq, Hash, PartialOrd, Ord, Copy)]
    479
    #[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
    480
    pub enum UnionMode {
    481
        /// Sparse union layout
    482
        Sparse,
    483
        /// Dense union layout
    484
        Dense,
    485
    }
    486
    487
    impl fmt::Display for DataType {
    488
    0
        fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
    489
    0
            match &self {
    490
    0
                DataType::Struct(fields) => {
    491
    0
                    write!(f, "Struct(")?;
    492
    0
                    if !fields.is_empty() {
    493
    0
                        let fields_str = fields
    494
    0
                            .iter()
    495
    0
                            .map(|f| format!("{} {}", f.name(), f.data_type()))
    496
    0
                            .collect::<Vec<_>>()
    497
    0
                            .join(", ");
    498
    0
                        write!(f, "{fields_str}")?;
    499
    0
                    }
    500
    0
                    write!(f, ")")?;
    501
    0
                    Ok(())
    502
                }
    503
    0
                _ => write!(f, "{self:?}"),
    504
            }
    505
    0
        }
    506
    }
    507
    508
    /// Parses `str` into a `DataType`.
    509
    ///
    510
    /// This is the reverse of [`DataType`]'s `Display`
    511
    /// impl, and maintains the invariant that
    512
    /// `DataType::try_from(&data_type.to_string()).unwrap() == data_type`
    513
    ///
    514
    /// # Example
    515
    /// ```
    516
    /// use arrow_schema::DataType;
    517
    ///
    518
    /// let data_type: DataType = "Int32".parse().unwrap();
    519
    /// assert_eq!(data_type, DataType::Int32);
    520
    /// ```
    521
    impl FromStr for DataType {
    522
        type Err = ArrowError;
    523
    524
    0
        fn from_str(s: &str) -> Result<Self, Self::Err> {
    525
    0
            crate::datatype_parse::parse_data_type(s)
    526
    0
        }
    527
    }
    528
    529
    impl TryFrom<&str> for DataType {
    530
        type Error = ArrowError;
    531
    532
    0
        fn try_from(value: &str) -> Result<Self, Self::Error> {
    533
    0
            value.parse()
    534
    0
        }
    535
    }
    536
    537
    impl DataType {
    538
        /// Returns true if the type is primitive: (numeric, temporal).
    539
        #[inline]
    540
    0
        pub fn is_primitive(&self) -> bool {
    541
    0
            self.is_numeric() || self.is_temporal()
    542
    0
        }
    543
    544
        /// Returns true if this type is numeric: (UInt*, Int*, Float*, Decimal*).
    545
        #[inline]
    546
    0
        pub fn is_numeric(&self) -> bool {
    547
            use DataType::*;
    548
    0
            matches!(
    549
    0
                self,
    550
                UInt8
    551
                    | UInt16
    552
                    | UInt32
    553
                    | UInt64
    554
                    | Int8
    555
                    | Int16
    556
                    | Int32
    557
                    | Int64
    558
                    | Float16
    559
                    | Float32
    560
                    | Float64
    561
                    | Decimal32(_, _)
    562
                    | Decimal64(_, _)
    563
                    | Decimal128(_, _)
    564
                    | Decimal256(_, _)
    565
            )
    566
    0
        }
    567
    568
        /// Returns true if this type is temporal: (Date*, Time*, Duration, or Interval).
    569
        #[inline]
    570
    0
        pub fn is_temporal(&self) -> bool {
    571
            use DataType::*;
    572
    0
            matches!(
    573
    0
                self,
    574
                Date32 | Date64 | Timestamp(_, _) | Time32(_) | Time64(_) | Duration(_) | Interval(_)
    575
            )
    576
    0
        }
    577
    578
        /// Returns true if this type is floating: (Float*).
    579
        #[inline]
    580
    0
        pub fn is_floating(&self) -> bool {
    581
            use DataType::*;
    582
    0
            matches!(self, Float16 | Float32 | Float64)
    583
    0
        }
    584
    585
        /// Returns true if this type is integer: (Int*, UInt*).
    586
        #[inline]
    587
    0
        pub fn is_integer(&self) -> bool {
    588
    0
            self.is_signed_integer() || self.is_unsigned_integer()
    589
    0
        }
    590
    591
        /// Returns true if this type is signed integer: (Int*).
    592
        #[inline]
    593
    0
        pub fn is_signed_integer(&self) -> bool {
    594
            use DataType::*;
    595
    0
            matches!(self, Int8 | Int16 | Int32 | Int64)
    596
    0
        }
    597
    598
        /// Returns true if this type is unsigned integer: (UInt*).
    599
        #[inline]
    600
    0
        pub fn is_unsigned_integer(&self) -> bool {
    601
            use DataType::*;
    602
    0
            matches!(self, UInt8 | UInt16 | UInt32 | UInt64)
    603
    0
        }
    604
    605
        /// Returns true if this type is valid as a dictionary key
    606
        #[inline]
    607
    0
        pub fn is_dictionary_key_type(&self) -> bool {
    608
    0
            self.is_integer()
    609
    0
        }
    610
    611
        /// Returns true if this type is valid for run-ends array in RunArray
    612
        #[inline]
    613
    0
        pub fn is_run_ends_type(&self) -> bool {
    614
            use DataType::*;
    615
    0
            matches!(self, Int16 | Int32 | Int64)
    616
    0
        }
    617
    618
        /// Returns true if this type is nested (List, FixedSizeList, LargeList, ListView. LargeListView, Struct, Union,
    619
        /// or Map), or a dictionary of a nested type
    620
        #[inline]
    621
    0
        pub fn is_nested(&self) -> bool {
    622
            use DataType::*;
    623
    0
            match self {
    624
    0
                Dictionary(_, v) => DataType::is_nested(v.as_ref()),
    625
    0
                RunEndEncoded(_, v) => DataType::is_nested(v.data_type()),
    626
                List(_)
    627
                | FixedSizeList(_, _)
    628
                | LargeList(_)
    629
                | ListView(_)
    630
                | LargeListView(_)
    631
                | Struct(_)
    632
                | Union(_, _)
    633
    0
                | Map(_, _) => true,
    634
    0
                _ => false,
    635
            }
    636
    0
        }
    637
    638
        /// Returns true if this type is DataType::Null.
    639
        #[inline]
    640
    0
        pub fn is_null(&self) -> bool {
    641
            use DataType::*;
    642
    0
            matches!(self, Null)
    643
    0
        }
    644
    645
        /// Compares the datatype with another, ignoring nested field names
    646
        /// and metadata.
    647
    0
        pub fn equals_datatype(&self, other: &DataType) -> bool {
    648
    0
            match (&self, other) {
    649
    0
                (DataType::List(a), DataType::List(b))
    650
    0
                | (DataType::LargeList(a), DataType::LargeList(b))
    651
    0
                | (DataType::ListView(a), DataType::ListView(b))
    652
    0
                | (DataType::LargeListView(a), DataType::LargeListView(b)) => {
    653
    0
                    a.is_nullable() == b.is_nullable() && a.data_type().equals_datatype(b.data_type())
    654
                }
    655
    0
                (DataType::FixedSizeList(a, a_size), DataType::FixedSizeList(b, b_size)) => {
    656
    0
                    a_size == b_size
    657
    0
                        && a.is_nullable() == b.is_nullable()
    658
    0
                        && a.data_type().equals_datatype(b.data_type())
    659
                }
    660
    0
                (DataType::Struct(a), DataType::Struct(b)) => {
    661
    0
                    a.len() == b.len()
    662
    0
                        && a.iter().zip(b).all(|(a, b)| {
    663
    0
                            a.is_nullable() == b.is_nullable()
    664
    0
                                && a.data_type().equals_datatype(b.data_type())
    665
    0
                        })
    666
                }
    667
    0
                (DataType::Map(a_field, a_is_sorted), DataType::Map(b_field, b_is_sorted)) => {
    668
    0
                    a_field.is_nullable() == b_field.is_nullable()
    669
    0
                        && a_field.data_type().equals_datatype(b_field.data_type())
    670
    0
                        && a_is_sorted == b_is_sorted
    671
                }
    672
    0
                (DataType::Dictionary(a_key, a_value), DataType::Dictionary(b_key, b_value)) => {
    673
    0
                    a_key.equals_datatype(b_key) && a_value.equals_datatype(b_value)
    674
                }
    675
                (
    676
    0
                    DataType::RunEndEncoded(a_run_ends, a_values),
    677
    0
                    DataType::RunEndEncoded(b_run_ends, b_values),
    678
                ) => {
    679
    0
                    a_run_ends.is_nullable() == b_run_ends.is_nullable()
    680
    0
                        && a_run_ends
    681
    0
                            .data_type()
    682
    0
                            .equals_datatype(b_run_ends.data_type())
    683
    0
                        && a_values.is_nullable() == b_values.is_nullable()
    684
    0
                        && a_values.data_type().equals_datatype(b_values.data_type())
    685
                }
    686
                (
    687
    0
                    DataType::Union(a_union_fields, a_union_mode),
    688
    0
                    DataType::Union(b_union_fields, b_union_mode),
    689
                ) => {
    690
    0
                    a_union_mode == b_union_mode
    691
    0
                        && a_union_fields.len() == b_union_fields.len()
    692
    0
                        && a_union_fields.iter().all(|a| {
    693
    0
                            b_union_fields.iter().any(|b| {
    694
    0
                                a.0 == b.0
    695
    0
                                    && a.1.is_nullable() == b.1.is_nullable()
    696
    0
                                    && a.1.data_type().equals_datatype(b.1.data_type())
    697
    0
                            })
    698
    0
                        })
    699
                }
    700
    0
                _ => self == other,
    701
            }
    702
    0
        }
    703
    704
        /// Returns the byte width of this type if it is a primitive type
    705
        ///
    706
        /// Returns `None` if not a primitive type
    707
        #[inline]
    708
    3
        pub fn primitive_width(&self) -> Option<usize> {
    709
    0
            match self {
    710
    0
                DataType::Null => None,
    711
    0
                DataType::Boolean => None,
    712
    0
                DataType::Int8 | DataType::UInt8 => Some(1),
    713
    0
                DataType::Int16 | DataType::UInt16 | DataType::Float16 => Some(2),
    714
    2
                DataType::Int32 | DataType::UInt32 | DataType::Float32 => Some(4),
    715
    1
                DataType::Int64 | DataType::UInt64 | DataType::Float64 => Some(8),
    716
    0
                DataType::Timestamp(_, _) => Some(8),
    717
    0
                DataType::Date32 | DataType::Time32(_) => Some(4),
    718
    0
                DataType::Date64 | DataType::Time64(_) => Some(8),
    719
    0
                DataType::Duration(_) => Some(8),
    720
    0
                DataType::Interval(IntervalUnit::YearMonth) => Some(4),
    721
    0
                DataType::Interval(IntervalUnit::DayTime) => Some(8),
    722
    0
                DataType::Interval(IntervalUnit::MonthDayNano) => Some(16),
    723
    0
                DataType::Decimal32(_, _) => Some(4),
    724
    0
                DataType::Decimal64(_, _) => Some(8),
    725
    0
                DataType::Decimal128(_, _) => Some(16),
    726
    0
                DataType::Decimal256(_, _) => Some(32),
    727
    0
                DataType::Utf8 | DataType::LargeUtf8 | DataType::Utf8View => None,
    728
    0
                DataType::Binary | DataType::LargeBinary | DataType::BinaryView => None,
    729
    0
                DataType::FixedSizeBinary(_) => None,
    730
                DataType::List(_)
    731
                | DataType::ListView(_)
    732
                | DataType::LargeList(_)
    733
                | DataType::LargeListView(_)
    734
    0
                | DataType::Map(_, _) => None,
    735
    0
                DataType::FixedSizeList(_, _) => None,
    736
    0
                DataType::Struct(_) => None,
    737
    0
                DataType::Union(_, _) => None,
    738
    0
                DataType::Dictionary(_, _) => None,
    739
    0
                DataType::RunEndEncoded(_, _) => None,
    740
            }
    741
    3
        }
    742
    743
        /// Return size of this instance in bytes.
    744
        ///
    745
        /// Includes the size of `Self`.
    746
    0
        pub fn size(&self) -> usize {
    747
    0
            std::mem::size_of_val(self)
    748
    0
                + match self {
    749
                    DataType::Null
    750
                    | DataType::Boolean
    751
                    | DataType::Int8
    752
                    | DataType::Int16
    753
                    | DataType::Int32
    754
                    | DataType::Int64
    755
                    | DataType::UInt8
    756
                    | DataType::UInt16
    757
                    | DataType::UInt32
    758
                    | DataType::UInt64
    759
                    | DataType::Float16
    760
                    | DataType::Float32
    761
                    | DataType::Float64
    762
                    | DataType::Date32
    763
                    | DataType::Date64
    764
                    | DataType::Time32(_)
    765
                    | DataType::Time64(_)
    766
                    | DataType::Duration(_)
    767
                    | DataType::Interval(_)
    768
                    | DataType::Binary
    769
                    | DataType::FixedSizeBinary(_)
    770
                    | DataType::LargeBinary
    771
                    | DataType::BinaryView
    772
                    | DataType::Utf8
    773
                    | DataType::LargeUtf8
    774
                    | DataType::Utf8View
    775
                    | DataType::Decimal32(_, _)
    776
                    | DataType::Decimal64(_, _)
    777
                    | DataType::Decimal128(_, _)
    778
    0
                    | DataType::Decimal256(_, _) => 0,
    779
    0
                    DataType::Timestamp(_, s) => s.as_ref().map(|s| s.len()).unwrap_or_default(),
    780
    0
                    DataType::List(field)
    781
    0
                    | DataType::ListView(field)
    782
    0
                    | DataType::FixedSizeList(field, _)
    783
    0
                    | DataType::LargeList(field)
    784
    0
                    | DataType::LargeListView(field)
    785
    0
                    | DataType::Map(field, _) => field.size(),
    786
    0
                    DataType::Struct(fields) => fields.size(),
    787
    0
                    DataType::Union(fields, _) => fields.size(),
    788
    0
                    DataType::Dictionary(dt1, dt2) => dt1.size() + dt2.size(),
    789
    0
                    DataType::RunEndEncoded(run_ends, values) => {
    790
    0
                        run_ends.size() - std::mem::size_of_val(run_ends) + values.size()
    791
    0
                            - std::mem::size_of_val(values)
    792
                    }
    793
                }
    794
    0
        }
    795
    796
        /// Check to see if `self` is a superset of `other`
    797
        ///
    798
        /// If DataType is a nested type, then it will check to see if the nested type is a superset of the other nested type
    799
        /// else it will check to see if the DataType is equal to the other DataType
    800
    0
        pub fn contains(&self, other: &DataType) -> bool {
    801
    0
            match (self, other) {
    802
    0
                (DataType::List(f1), DataType::List(f2))
    803
    0
                | (DataType::LargeList(f1), DataType::LargeList(f2))
    804
    0
                | (DataType::ListView(f1), DataType::ListView(f2))
    805
    0
                | (DataType::LargeListView(f1), DataType::LargeListView(f2)) => f1.contains(f2),
    806
    0
                (DataType::FixedSizeList(f1, s1), DataType::FixedSizeList(f2, s2)) => {
    807
    0
                    s1 == s2 && f1.contains(f2)
    808
                }
    809
    0
                (DataType::Map(f1, s1), DataType::Map(f2, s2)) => s1 == s2 && f1.contains(f2),
    810
    0
                (DataType::Struct(f1), DataType::Struct(f2)) => f1.contains(f2),
    811
    0
                (DataType::Union(f1, s1), DataType::Union(f2, s2)) => {
    812
    0
                    s1 == s2
    813
    0
                        && f1
    814
    0
                            .iter()
    815
    0
                            .all(|f1| f2.iter().any(|f2| f1.0 == f2.0 && f1.1.contains(f2.1)))
    816
                }
    817
    0
                (DataType::Dictionary(k1, v1), DataType::Dictionary(k2, v2)) => {
    818
    0
                    k1.contains(k2) && v1.contains(v2)
    819
                }
    820
    0
                _ => self == other,
    821
            }
    822
    0
        }
    823
    824
        /// Create a [`DataType::List`] with elements of the specified type
    825
        /// and nullability, and conventionally named inner [`Field`] (`"item"`).
    826
        ///
    827
        /// To specify field level metadata, construct the inner [`Field`]
    828
        /// directly via [`Field::new`] or [`Field::new_list_field`].
    829
    0
        pub fn new_list(data_type: DataType, nullable: bool) -> Self {
    830
    0
            DataType::List(Arc::new(Field::new_list_field(data_type, nullable)))
    831
    0
        }
    832
    833
        /// Create a [`DataType::LargeList`] with elements of the specified type
    834
        /// and nullability, and conventionally named inner [`Field`] (`"item"`).
    835
        ///
    836
        /// To specify field level metadata, construct the inner [`Field`]
    837
        /// directly via [`Field::new`] or [`Field::new_list_field`].
    838
    0
        pub fn new_large_list(data_type: DataType, nullable: bool) -> Self {
    839
    0
            DataType::LargeList(Arc::new(Field::new_list_field(data_type, nullable)))
    840
    0
        }
    841
    842
        /// Create a [`DataType::FixedSizeList`] with elements of the specified type, size
    843
        /// and nullability, and conventionally named inner [`Field`] (`"item"`).
    844
        ///
    845
        /// To specify field level metadata, construct the inner [`Field`]
    846
        /// directly via [`Field::new`] or [`Field::new_list_field`].
    847
    0
        pub fn new_fixed_size_list(data_type: DataType, size: i32, nullable: bool) -> Self {
    848
    0
            DataType::FixedSizeList(Arc::new(Field::new_list_field(data_type, nullable)), size)
    849
    0
        }
    850
    }
    851
    852
    /// The maximum precision for [DataType::Decimal32] values
    853
    pub const DECIMAL32_MAX_PRECISION: u8 = 9;
    854
    855
    /// The maximum scale for [DataType::Decimal32] values
    856
    pub const DECIMAL32_MAX_SCALE: i8 = 9;
    857
    858
    /// The maximum precision for [DataType::Decimal64] values
    859
    pub const DECIMAL64_MAX_PRECISION: u8 = 18;
    860
    861
    /// The maximum scale for [DataType::Decimal64] values
    862
    pub const DECIMAL64_MAX_SCALE: i8 = 18;
    863
    864
    /// The maximum precision for [DataType::Decimal128] values
    865
    pub const DECIMAL128_MAX_PRECISION: u8 = 38;
    866
    867
    /// The maximum scale for [DataType::Decimal128] values
    868
    pub const DECIMAL128_MAX_SCALE: i8 = 38;
    869
    870
    /// The maximum precision for [DataType::Decimal256] values
    871
    pub const DECIMAL256_MAX_PRECISION: u8 = 76;
    872
    873
    /// The maximum scale for [DataType::Decimal256] values
    874
    pub const DECIMAL256_MAX_SCALE: i8 = 76;
    875
    876
    /// The default scale for [DataType::Decimal32] values
    877
    pub const DECIMAL32_DEFAULT_SCALE: i8 = 2;
    878
    879
    /// The default scale for [DataType::Decimal64] values
    880
    pub const DECIMAL64_DEFAULT_SCALE: i8 = 6;
    881
    882
    /// The default scale for [DataType::Decimal128] and [DataType::Decimal256]
    883
    /// values
    884
    pub const DECIMAL_DEFAULT_SCALE: i8 = 10;
    885
    886
    #[cfg(test)]
    887
    mod tests {
    888
        use super::*;
    889
    890
        #[test]
    891
        #[cfg(feature = "serde")]
    892
        fn serde_struct_type() {
    893
            use std::collections::HashMap;
    894
    895
            let kv_array = [("k".to_string(), "v".to_string())];
    896
            let field_metadata: HashMap<String, String> = kv_array.iter().cloned().collect();
    897
    898
            // Non-empty map: should be converted as JSON obj { ... }
    899
            let first_name =
    900
                Field::new("first_name", DataType::Utf8, false).with_metadata(field_metadata);
    901
    902
            // Empty map: should be omitted.
    903
            let last_name =
    904
                Field::new("last_name", DataType::Utf8, false).with_metadata(HashMap::default());
    905
    906
            let person = DataType::Struct(Fields::from(vec![
    907
                first_name,
    908
                last_name,
    909
                Field::new(
    910
                    "address",
    911
                    DataType::Struct(Fields::from(vec![
    912
                        Field::new("street", DataType::Utf8, false),
    913
                        Field::new("zip", DataType::UInt16, false),
    914
                    ])),
    915
                    false,
    916
                ),
    917
            ]));
    918
    919
            let serialized = serde_json::to_string(&person).unwrap();
    920
    921
            // NOTE that this is testing the default (derived) serialization format, not the
    922
            // JSON format specified in metadata.md
    923
    924
            assert_eq!(
    925
                "{\"Struct\":[\
    926
                 {\"name\":\"first_name\",\"data_type\":\"Utf8\",\"nullable\":false,\"dict_id\":0,\"dict_is_ordered\":false,\"metadata\":{\"k\":\"v\"}},\
    927
                 {\"name\":\"last_name\",\"data_type\":\"Utf8\",\"nullable\":false,\"dict_id\":0,\"dict_is_ordered\":false,\"metadata\":{}},\
    928
                 {\"name\":\"address\",\"data_type\":{\"Struct\":\
    929
                 [{\"name\":\"street\",\"data_type\":\"Utf8\",\"nullable\":false,\"dict_id\":0,\"dict_is_ordered\":false,\"metadata\":{}},\
    930
                 {\"name\":\"zip\",\"data_type\":\"UInt16\",\"nullable\":false,\"dict_id\":0,\"dict_is_ordered\":false,\"metadata\":{}}\
    931
                 ]},\"nullable\":false,\"dict_id\":0,\"dict_is_ordered\":false,\"metadata\":{}}]}",
    932
                serialized
    933
            );
    934
    935
            let deserialized = serde_json::from_str(&serialized).unwrap();
    936
    937
            assert_eq!(person, deserialized);
    938
        }
    939
    940
        #[test]
    941
        fn test_list_datatype_equality() {
    942
            // tests that list type equality is checked while ignoring list names
    943
            let list_a = DataType::List(Arc::new(Field::new_list_field(DataType::Int32, true)));
    944
            let list_b = DataType::List(Arc::new(Field::new("array", DataType::Int32, true)));
    945
            let list_c = DataType::List(Arc::new(Field::new_list_field(DataType::Int32, false)));
    946
            let list_d = DataType::List(Arc::new(Field::new_list_field(DataType::UInt32, true)));
    947
            assert!(list_a.equals_datatype(&list_b));
    948
            assert!(!list_a.equals_datatype(&list_c));
    949
            assert!(!list_b.equals_datatype(&list_c));
    950
            assert!(!list_a.equals_datatype(&list_d));
    951
    952
            let list_e =
    953
                DataType::FixedSizeList(Arc::new(Field::new_list_field(list_a.clone(), false)), 3);
    954
            let list_f =
    955
                DataType::FixedSizeList(Arc::new(Field::new("array", list_b.clone(), false)), 3);
    956
            let list_g = DataType::FixedSizeList(
    957
                Arc::new(Field::new_list_field(DataType::FixedSizeBinary(3), true)),
    958
                3,
    959
            );
    960
            assert!(list_e.equals_datatype(&list_f));
    961
            assert!(!list_e.equals_datatype(&list_g));
    962
            assert!(!list_f.equals_datatype(&list_g));
    963
    964
            let list_h = DataType::Struct(Fields::from(vec![Field::new("f1", list_e, true)]));
    965
            let list_i = DataType::Struct(Fields::from(vec![Field::new("f1", list_f.clone(), true)]));
    966
            let list_j = DataType::Struct(Fields::from(vec![Field::new("f1", list_f.clone(), false)]));
    967
            let list_k = DataType::Struct(Fields::from(vec![
    968
                Field::new("f1", list_f.clone(), false),
    969
                Field::new("f2", list_g.clone(), false),
    970
                Field::new("f3", DataType::Utf8, true),
    971
            ]));
    972
            let list_l = DataType::Struct(Fields::from(vec![
    973
                Field::new("ff1", list_f.clone(), false),
    974
                Field::new("ff2", list_g.clone(), false),
    975
                Field::new("ff3", DataType::LargeUtf8, true),
    976
            ]));
    977
            let list_m = DataType::Struct(Fields::from(vec![
    978
                Field::new("ff1", list_f, false),
    979
                Field::new("ff2", list_g, false),
    980
                Field::new("ff3", DataType::Utf8, true),
    981
            ]));
    982
            assert!(list_h.equals_datatype(&list_i));
    983
            assert!(!list_h.equals_datatype(&list_j));
    984
            assert!(!list_k.equals_datatype(&list_l));
    985
            assert!(list_k.equals_datatype(&list_m));
    986
    987
            let list_n = DataType::Map(Arc::new(Field::new("f1", list_a.clone(), true)), true);
    988
            let list_o = DataType::Map(Arc::new(Field::new("f2", list_b.clone(), true)), true);
    989
            let list_p = DataType::Map(Arc::new(Field::new("f2", list_b.clone(), true)), false);
    990
            let list_q = DataType::Map(Arc::new(Field::new("f2", list_c.clone(), true)), true);
    991
            let list_r = DataType::Map(Arc::new(Field::new("f1", list_a.clone(), false)), true);
    992
    993
            assert!(list_n.equals_datatype(&list_o));
    994
            assert!(!list_n.equals_datatype(&list_p));
    995
            assert!(!list_n.equals_datatype(&list_q));
    996
            assert!(!list_n.equals_datatype(&list_r));
    997
    998
            let list_s = DataType::Dictionary(Box::new(DataType::UInt8), Box::new(list_a));
    999
            let list_t = DataType::Dictionary(Box::new(DataType::UInt8), Box::new(list_b.clone()));
    1000
            let list_u = DataType::Dictionary(Box::new(DataType::Int8), Box::new(list_b));
    1001
            let list_v = DataType::Dictionary(Box::new(DataType::UInt8), Box::new(list_c));
    1002
    1003
            assert!(list_s.equals_datatype(&list_t));
    1004
            assert!(!list_s.equals_datatype(&list_u));
    1005
            assert!(!list_s.equals_datatype(&list_v));
    1006
    1007
            let union_a = DataType::Union(
    1008
                UnionFields::new(
    1009
                    vec![1, 2],
    1010
                    vec![
    1011
                        Field::new("f1", DataType::Utf8, false),
    1012
                        Field::new("f2", DataType::UInt8, false),
    1013
                    ],
    1014
                ),
    1015
                UnionMode::Sparse,
    1016
            );
    1017
            let union_b = DataType::Union(
    1018
                UnionFields::new(
    1019
                    vec![1, 2],
    1020
                    vec![
    1021
                        Field::new("ff1", DataType::Utf8, false),
    1022
                        Field::new("ff2", DataType::UInt8, false),
    1023
                    ],
    1024
                ),
    1025
                UnionMode::Sparse,
    1026
            );
    1027
            let union_c = DataType::Union(
    1028
                UnionFields::new(
    1029
                    vec![2, 1],
    1030
                    vec![
    1031
                        Field::new("fff2", DataType::UInt8, false),
    1032
                        Field::new("fff1", DataType::Utf8, false),
    1033
                    ],
    1034
                ),
    1035
                UnionMode::Sparse,
    1036
            );
    1037
            let union_d = DataType::Union(
    1038
                UnionFields::new(
    1039
                    vec![2, 1],
    1040
                    vec![
    1041
                        Field::new("fff1", DataType::Int8, false),
    1042
                        Field::new("fff2", DataType::UInt8, false),
    1043
                    ],
    1044
                ),
    1045
                UnionMode::Sparse,
    1046
            );
    1047
            let union_e = DataType::Union(
    1048
                UnionFields::new(
    1049
                    vec![1, 2],
    1050
                    vec![
    1051
                        Field::new("f1", DataType::Utf8, true),
    1052
                        Field::new("f2", DataType::UInt8, false),
    1053
                    ],
    1054
                ),
    1055
                UnionMode::Sparse,
    1056
            );
    1057
    1058
            assert!(union_a.equals_datatype(&union_b));
    1059
            assert!(union_a.equals_datatype(&union_c));
    1060
            assert!(!union_a.equals_datatype(&union_d));
    1061
            assert!(!union_a.equals_datatype(&union_e));
    1062
    1063
            let list_w = DataType::RunEndEncoded(
    1064
                Arc::new(Field::new("f1", DataType::Int64, true)),
    1065
                Arc::new(Field::new("f2", DataType::Utf8, true)),
    1066
            );
    1067
            let list_x = DataType::RunEndEncoded(
    1068
                Arc::new(Field::new("ff1", DataType::Int64, true)),
    1069
                Arc::new(Field::new("ff2", DataType::Utf8, true)),
    1070
            );
    1071
            let list_y = DataType::RunEndEncoded(
    1072
                Arc::new(Field::new("ff1", DataType::UInt16, true)),
    1073
                Arc::new(Field::new("ff2", DataType::Utf8, true)),
    1074
            );
    1075
            let list_z = DataType::RunEndEncoded(
    1076
                Arc::new(Field::new("f1", DataType::Int64, false)),
    1077
                Arc::new(Field::new("f2", DataType::Utf8, true)),
    1078
            );
    1079
    1080
            assert!(list_w.equals_datatype(&list_x));
    1081
            assert!(!list_w.equals_datatype(&list_y));
    1082
            assert!(!list_w.equals_datatype(&list_z));
    1083
        }
    1084
    1085
        #[test]
    1086
        fn create_struct_type() {
    1087
            let _person = DataType::Struct(Fields::from(vec![
    1088
                Field::new("first_name", DataType::Utf8, false),
    1089
                Field::new("last_name", DataType::Utf8, false),
    1090
                Field::new(
    1091
                    "address",
    1092
                    DataType::Struct(Fields::from(vec![
    1093
                        Field::new("street", DataType::Utf8, false),
    1094
                        Field::new("zip", DataType::UInt16, false),
    1095
                    ])),
    1096
                    false,
    1097
                ),
    1098
            ]));
    1099
        }
    1100
    1101
        #[test]
    1102
        fn test_nested() {
    1103
            let list = DataType::List(Arc::new(Field::new("foo", DataType::Utf8, true)));
    1104
            let list_view = DataType::ListView(Arc::new(Field::new("foo", DataType::Utf8, true)));
    1105
            let large_list_view =
    1106
                DataType::LargeListView(Arc::new(Field::new("foo", DataType::Utf8, true)));
    1107
    1108
            assert!(!DataType::is_nested(&DataType::Boolean));
    1109
            assert!(!DataType::is_nested(&DataType::Int32));
    1110
            assert!(!DataType::is_nested(&DataType::Utf8));
    1111
            assert!(DataType::is_nested(&list));
    1112
            assert!(DataType::is_nested(&list_view));
    1113
            assert!(DataType::is_nested(&large_list_view));
    1114
    1115
            assert!(!DataType::is_nested(&DataType::Dictionary(
    1116
                Box::new(DataType::Int32),
    1117
                Box::new(DataType::Boolean)
    1118
            )));
    1119
            assert!(!DataType::is_nested(&DataType::Dictionary(
    1120
                Box::new(DataType::Int32),
    1121
                Box::new(DataType::Int64)
    1122
            )));
    1123
            assert!(!DataType::is_nested(&DataType::Dictionary(
    1124
                Box::new(DataType::Int32),
    1125
                Box::new(DataType::LargeUtf8)
    1126
            )));
    1127
            assert!(DataType::is_nested(&DataType::Dictionary(
    1128
                Box::new(DataType::Int32),
    1129
                Box::new(list)
    1130
            )));
    1131
        }
    1132
    1133
        #[test]
    1134
        fn test_integer() {
    1135
            // is_integer
    1136
            assert!(DataType::is_integer(&DataType::Int32));
    1137
            assert!(DataType::is_integer(&DataType::UInt64));
    1138
            assert!(!DataType::is_integer(&DataType::Float16));
    1139
    1140
            // is_signed_integer
    1141
            assert!(DataType::is_signed_integer(&DataType::Int32));
    1142
            assert!(!DataType::is_signed_integer(&DataType::UInt64));
    1143
            assert!(!DataType::is_signed_integer(&DataType::Float16));
    1144
    1145
            // is_unsigned_integer
    1146
            assert!(!DataType::is_unsigned_integer(&DataType::Int32));
    1147
            assert!(DataType::is_unsigned_integer(&DataType::UInt64));
    1148
            assert!(!DataType::is_unsigned_integer(&DataType::Float16));
    1149
    1150
            // is_dictionary_key_type
    1151
            assert!(DataType::is_dictionary_key_type(&DataType::Int32));
    1152
            assert!(DataType::is_dictionary_key_type(&DataType::UInt64));
    1153
            assert!(!DataType::is_dictionary_key_type(&DataType::Float16));
    1154
        }
    1155
    1156
        #[test]
    1157
        fn test_floating() {
    1158
            assert!(DataType::is_floating(&DataType::Float16));
    1159
            assert!(!DataType::is_floating(&DataType::Int32));
    1160
        }
    1161
    1162
        #[test]
    1163
        fn test_datatype_is_null() {
    1164
            assert!(DataType::is_null(&DataType::Null));
    1165
            assert!(!DataType::is_null(&DataType::Int32));
    1166
        }
    1167
    1168
        #[test]
    1169
        fn size_should_not_regress() {
    1170
            assert_eq!(std::mem::size_of::<DataType>(), 24);
    1171
        }
    1172
    1173
        #[test]
    1174
        #[should_panic(expected = "duplicate type id: 1")]
    1175
        fn test_union_with_duplicated_type_id() {
    1176
            let type_ids = vec![1, 1];
    1177
            let _union = DataType::Union(
    1178
                UnionFields::new(
    1179
                    type_ids,
    1180
                    vec![
    1181
                        Field::new("f1", DataType::Int32, false),
    1182
                        Field::new("f2", DataType::Utf8, false),
    1183
                    ],
    1184
                ),
    1185
                UnionMode::Dense,
    1186
            );
    1187
        }
    1188
    1189
        #[test]
    1190
        fn test_try_from_str() {
    1191
            let data_type: DataType = "Int32".try_into().unwrap();
    1192
            assert_eq!(data_type, DataType::Int32);
    1193
        }
    1194
    1195
        #[test]
    1196
        fn test_from_str() {
    1197
            let data_type: DataType = "UInt64".parse().unwrap();
    1198
            assert_eq!(data_type, DataType::UInt64);
    1199
        }
    1200
    }