Coverage Report

Created: 2024-10-13 08:39

/Users/andrewlamb/Software/datafusion/datafusion/expr/src/type_coercion/mod.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
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//
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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.
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//! Type coercion rules for DataFusion
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//!
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//! Coercion is performed automatically by DataFusion when the types
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//! of arguments passed to a function or needed by operators do not
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//! exactly match the types required by that function / operator. In
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//! this case, DataFusion will attempt to *coerce* the arguments to
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//! types accepted by the function by inserting CAST operations.
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//!
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//! CAST operations added by coercion are lossless and never discard
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//! information.
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//!
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//! For example coercion from i32 -> i64 might be
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//! performed because all valid i32 values can be represented using an
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//! i64. However, i64 -> i32 is never performed as there are i64
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//! values which can not be represented by i32 values.
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pub mod aggregates {
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    pub use datafusion_expr_common::type_coercion::aggregates::*;
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}
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pub mod functions;
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pub mod other;
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pub use datafusion_expr_common::type_coercion::binary;
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use arrow::datatypes::DataType;
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/// Determine whether the given data type `dt` represents signed numeric values.
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pub fn is_signed_numeric(dt: &DataType) -> bool {
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    matches!(
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        dt,
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        DataType::Int8
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            | DataType::Int16
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            | DataType::Int32
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            | DataType::Int64
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            | DataType::Float16
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            | DataType::Float32
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            | DataType::Float64
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            | DataType::Decimal128(_, _)
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            | DataType::Decimal256(_, _),
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    )
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}
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/// Determine whether the given data type `dt` is `Null`.
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pub fn is_null(dt: &DataType) -> bool {
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    *dt == DataType::Null
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}
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/// Determine whether the given data type `dt` is a `Timestamp`.
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pub fn is_timestamp(dt: &DataType) -> bool {
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    matches!(dt, DataType::Timestamp(_, _))
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}
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/// Determine whether the given data type 'dt' is a `Interval`.
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pub fn is_interval(dt: &DataType) -> bool {
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    matches!(dt, DataType::Interval(_))
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}
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/// Determine whether the given data type `dt` is a `Date` or `Timestamp`.
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pub fn is_datetime(dt: &DataType) -> bool {
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    matches!(
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        dt,
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        DataType::Date32 | DataType::Date64 | DataType::Timestamp(_, _)
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    )
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}
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/// Determine whether the given data type `dt` is a `Utf8` or `LargeUtf8`.
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pub fn is_utf8_or_large_utf8(dt: &DataType) -> bool {
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    matches!(dt, DataType::Utf8 | DataType::LargeUtf8)
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}
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/// Determine whether the given data type `dt` is a `Decimal`.
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pub fn is_decimal(dt: &DataType) -> bool {
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    matches!(dt, DataType::Decimal128(_, _) | DataType::Decimal256(_, _))
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}