move to shared impl

Author: adriangb

datafusion/common/src/lib.rs

@@ -51,6 +51,7 @@ pub mod parsers;
 pub mod pruning;
 pub mod rounding;
 pub mod scalar;
+pub mod scalar_literal_cast;
 pub mod spans;
 pub mod stats;
 pub mod test_util;

datafusion/common/src/scalar_literal_cast.rs

@@ -0,0 +1,315 @@
+// 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.
+
+//! Utilities for casting scalar literals to different data types
+//!
+//! This module contains functions for casting ScalarValue literals
+//! to different data types, originally extracted from the optimizer's
+//! unwrap_cast module to be shared between logical and physical layers.
+
+use std::cmp::Ordering;
+
+use arrow::datatypes::{
+    DataType, TimeUnit, MAX_DECIMAL128_FOR_EACH_PRECISION,
+    MIN_DECIMAL128_FOR_EACH_PRECISION,
+};
+use arrow::temporal_conversions::{MICROSECONDS, MILLISECONDS, NANOSECONDS};
+
+use crate::ScalarValue;
+
+/// Convert a literal value from one data type to another
+pub fn try_cast_literal_to_type(
+    lit_value: &ScalarValue,
+    target_type: &DataType,
+) -> Option<ScalarValue> {
+    let lit_data_type = lit_value.data_type();
+    if !is_supported_type(&lit_data_type) || !is_supported_type(target_type) {
+        return None;
+    }
+    if lit_value.is_null() {
+        // null value can be cast to any type of null value
+        return ScalarValue::try_from(target_type).ok();
+    }
+    try_cast_numeric_literal(lit_value, target_type)
+        .or_else(|| try_cast_string_literal(lit_value, target_type))
+        .or_else(|| try_cast_dictionary(lit_value, target_type))
+        .or_else(|| try_cast_binary(lit_value, target_type))
+}
+
+/// Returns true if unwrap_cast_in_comparison supports this data type
+pub fn is_supported_type(data_type: &DataType) -> bool {
+    is_supported_numeric_type(data_type)
+        || is_supported_string_type(data_type)
+        || is_supported_dictionary_type(data_type)
+        || is_supported_binary_type(data_type)
+}
+
+/// Returns true if unwrap_cast_in_comparison support this numeric type
+pub fn is_supported_numeric_type(data_type: &DataType) -> bool {
+    matches!(
+        data_type,
+        DataType::UInt8
+            | DataType::UInt16
+            | DataType::UInt32
+            | DataType::UInt64
+            | DataType::Int8
+            | DataType::Int16
+            | DataType::Int32
+            | DataType::Int64
+            | DataType::Decimal128(_, _)
+            | DataType::Timestamp(_, _)
+    )
+}
+
+/// Returns true if unwrap_cast_in_comparison supports casting this value as a string
+pub fn is_supported_string_type(data_type: &DataType) -> bool {
+    matches!(
+        data_type,
+        DataType::Utf8 | DataType::LargeUtf8 | DataType::Utf8View
+    )
+}
+
+/// Returns true if unwrap_cast_in_comparison supports casting this value as a dictionary
+pub fn is_supported_dictionary_type(data_type: &DataType) -> bool {
+    matches!(data_type,
+                    DataType::Dictionary(_, inner) if is_supported_type(inner))
+}
+
+pub fn is_supported_binary_type(data_type: &DataType) -> bool {
+    matches!(data_type, DataType::Binary | DataType::FixedSizeBinary(_))
+}
+
+/// Convert a numeric value from one numeric data type to another
+pub fn try_cast_numeric_literal(
+    lit_value: &ScalarValue,
+    target_type: &DataType,
+) -> Option<ScalarValue> {
+    let lit_data_type = lit_value.data_type();
+    if !is_supported_numeric_type(&lit_data_type)
+        || !is_supported_numeric_type(target_type)
+    {
+        return None;
+    }
+
+    let mul = match target_type {
+        DataType::UInt8
+        | DataType::UInt16
+        | DataType::UInt32
+        | DataType::UInt64
+        | DataType::Int8
+        | DataType::Int16
+        | DataType::Int32
+        | DataType::Int64 => 1_i128,
+        DataType::Timestamp(_, _) => 1_i128,
+        DataType::Decimal128(_, scale) => 10_i128.pow(*scale as u32),
+        _ => return None,
+    };
+    let (target_min, target_max) = match target_type {
+        DataType::UInt8 => (u8::MIN as i128, u8::MAX as i128),
+        DataType::UInt16 => (u16::MIN as i128, u16::MAX as i128),
+        DataType::UInt32 => (u32::MIN as i128, u32::MAX as i128),
+        DataType::UInt64 => (u64::MIN as i128, u64::MAX as i128),
+        DataType::Int8 => (i8::MIN as i128, i8::MAX as i128),
+        DataType::Int16 => (i16::MIN as i128, i16::MAX as i128),
+        DataType::Int32 => (i32::MIN as i128, i32::MAX as i128),
+        DataType::Int64 => (i64::MIN as i128, i64::MAX as i128),
+        DataType::Timestamp(_, _) => (i64::MIN as i128, i64::MAX as i128),
+        DataType::Decimal128(precision, _) => (
+            // Different precision for decimal128 can store different range of value.
+            // For example, the precision is 3, the max of value is `999` and the min
+            // value is `-999`
+            MIN_DECIMAL128_FOR_EACH_PRECISION[*precision as usize],
+            MAX_DECIMAL128_FOR_EACH_PRECISION[*precision as usize],
+        ),
+        _ => return None,
+    };
+    let lit_value_target_type = match lit_value {
+        ScalarValue::Int8(Some(v)) => (*v as i128).checked_mul(mul),
+        ScalarValue::Int16(Some(v)) => (*v as i128).checked_mul(mul),
+        ScalarValue::Int32(Some(v)) => (*v as i128).checked_mul(mul),
+        ScalarValue::Int64(Some(v)) => (*v as i128).checked_mul(mul),
+        ScalarValue::UInt8(Some(v)) => (*v as i128).checked_mul(mul),
+        ScalarValue::UInt16(Some(v)) => (*v as i128).checked_mul(mul),
+        ScalarValue::UInt32(Some(v)) => (*v as i128).checked_mul(mul),
+        ScalarValue::UInt64(Some(v)) => (*v as i128).checked_mul(mul),
+        ScalarValue::TimestampSecond(Some(v), _) => (*v as i128).checked_mul(mul),
+        ScalarValue::TimestampMillisecond(Some(v), _) => (*v as i128).checked_mul(mul),
+        ScalarValue::TimestampMicrosecond(Some(v), _) => (*v as i128).checked_mul(mul),
+        ScalarValue::TimestampNanosecond(Some(v), _) => (*v as i128).checked_mul(mul),
+        ScalarValue::Decimal128(Some(v), _, scale) => {
+            let lit_scale_mul = 10_i128.pow(*scale as u32);
+            if mul >= lit_scale_mul {
+                // Example:
+                // lit is decimal(123,3,2)
+                // target type is decimal(5,3)
+                // the lit can be converted to the decimal(1230,5,3)
+                (*v).checked_mul(mul / lit_scale_mul)
+            } else if (*v) % (lit_scale_mul / mul) == 0 {
+                // Example:
+                // lit is decimal(123000,10,3)
+                // target type is int32: the lit can be converted to INT32(123)
+                // target type is decimal(10,2): the lit can be converted to decimal(12300,10,2)
+                Some(*v / (lit_scale_mul / mul))
+            } else {
+                // can't convert the lit decimal to the target data type
+                None
+            }
+        }
+        _ => None,
+    };
+
+    match lit_value_target_type {
+        None => None,
+        Some(value) => {
+            if value >= target_min && value <= target_max {
+                // the value casted from lit to the target type is in the range of target type.
+                // return the target type of scalar value
+                let result_scalar = match target_type {
+                    DataType::Int8 => ScalarValue::Int8(Some(value as i8)),
+                    DataType::Int16 => ScalarValue::Int16(Some(value as i16)),
+                    DataType::Int32 => ScalarValue::Int32(Some(value as i32)),
+                    DataType::Int64 => ScalarValue::Int64(Some(value as i64)),
+                    DataType::UInt8 => ScalarValue::UInt8(Some(value as u8)),
+                    DataType::UInt16 => ScalarValue::UInt16(Some(value as u16)),
+                    DataType::UInt32 => ScalarValue::UInt32(Some(value as u32)),
+                    DataType::UInt64 => ScalarValue::UInt64(Some(value as u64)),
+                    DataType::Timestamp(TimeUnit::Second, tz) => {
+                        let value = cast_between_timestamp(
+                            &lit_data_type,
+                            &DataType::Timestamp(TimeUnit::Second, tz.clone()),
+                            value,
+                        );
+                        ScalarValue::TimestampSecond(value, tz.clone())
+                    }
+                    DataType::Timestamp(TimeUnit::Millisecond, tz) => {
+                        let value = cast_between_timestamp(
+                            &lit_data_type,
+                            &DataType::Timestamp(TimeUnit::Millisecond, tz.clone()),
+                            value,
+                        );
+                        ScalarValue::TimestampMillisecond(value, tz.clone())
+                    }
+                    DataType::Timestamp(TimeUnit::Microsecond, tz) => {
+                        let value = cast_between_timestamp(
+                            &lit_data_type,
+                            &DataType::Timestamp(TimeUnit::Microsecond, tz.clone()),
+                            value,
+                        );
+                        ScalarValue::TimestampMicrosecond(value, tz.clone())
+                    }
+                    DataType::Timestamp(TimeUnit::Nanosecond, tz) => {
+                        let value = cast_between_timestamp(
+                            &lit_data_type,
+                            &DataType::Timestamp(TimeUnit::Nanosecond, tz.clone()),
+                            value,
+                        );
+                        ScalarValue::TimestampNanosecond(value, tz.clone())
+                    }
+                    DataType::Decimal128(p, s) => {
+                        ScalarValue::Decimal128(Some(value), *p, *s)
+                    }
+                    _ => {
+                        return None;
+                    }
+                };
+                Some(result_scalar)
+            } else {
+                None
+            }
+        }
+    }
+}
+
+pub fn try_cast_string_literal(
+    lit_value: &ScalarValue,
+    target_type: &DataType,
+) -> Option<ScalarValue> {
+    let string_value = lit_value.try_as_str()?.map(|s| s.to_string());
+    let scalar_value = match target_type {
+        DataType::Utf8 => ScalarValue::Utf8(string_value),
+        DataType::LargeUtf8 => ScalarValue::LargeUtf8(string_value),
+        DataType::Utf8View => ScalarValue::Utf8View(string_value),
+        _ => return None,
+    };
+    Some(scalar_value)
+}
+
+/// Attempt to cast to/from a dictionary type by wrapping/unwrapping the dictionary
+pub fn try_cast_dictionary(
+    lit_value: &ScalarValue,
+    target_type: &DataType,
+) -> Option<ScalarValue> {
+    let lit_value_type = lit_value.data_type();
+    let result_scalar = match (lit_value, target_type) {
+        // Unwrap dictionary when inner type matches target type
+        (ScalarValue::Dictionary(_, inner_value), _)
+            if inner_value.data_type() == *target_type =>
+        {
+            (**inner_value).clone()
+        }
+        // Wrap type when target type is dictionary
+        (_, DataType::Dictionary(index_type, inner_type))
+            if **inner_type == lit_value_type =>
+        {
+            ScalarValue::Dictionary(index_type.clone(), Box::new(lit_value.clone()))
+        }
+        _ => {
+            return None;
+        }
+    };
+    Some(result_scalar)
+}
+
+/// Cast a timestamp value from one unit to another
+pub fn cast_between_timestamp(from: &DataType, to: &DataType, value: i128) -> Option<i64> {
+    let value = value as i64;
+    let from_scale = match from {
+        DataType::Timestamp(TimeUnit::Second, _) => 1,
+        DataType::Timestamp(TimeUnit::Millisecond, _) => MILLISECONDS,
+        DataType::Timestamp(TimeUnit::Microsecond, _) => MICROSECONDS,
+        DataType::Timestamp(TimeUnit::Nanosecond, _) => NANOSECONDS,
+        _ => return Some(value),
+    };
+
+    let to_scale = match to {
+        DataType::Timestamp(TimeUnit::Second, _) => 1,
+        DataType::Timestamp(TimeUnit::Millisecond, _) => MILLISECONDS,
+        DataType::Timestamp(TimeUnit::Microsecond, _) => MICROSECONDS,
+        DataType::Timestamp(TimeUnit::Nanosecond, _) => NANOSECONDS,
+        _ => return Some(value),
+    };
+
+    match from_scale.cmp(&to_scale) {
+        Ordering::Less => value.checked_mul(to_scale / from_scale),
+        Ordering::Greater => Some(value / (from_scale / to_scale)),
+        Ordering::Equal => Some(value),
+    }
+}
+
+pub fn try_cast_binary(
+    lit_value: &ScalarValue,
+    target_type: &DataType,
+) -> Option<ScalarValue> {
+    match (lit_value, target_type) {
+        (ScalarValue::Binary(Some(v)), DataType::FixedSizeBinary(n))
+            if v.len() == *n as usize =>
+        {
+            Some(ScalarValue::FixedSizeBinary(*n, Some(v.clone())))
+        }
+        _ => None,
+    }
+}