jorgecarleitao commented on a change in pull request #9509:
URL: https://github.com/apache/arrow/pull/9509#discussion_r577283407
##########
File path: rust/datafusion/src/physical_plan/functions.rs
##########
@@ -617,48 +670,137 @@ mod tests {
};
use arrow::{
array::{
- ArrayRef, FixedSizeListArray, Float64Array, Int32Array,
StringArray,
+ Array, ArrayRef, FixedSizeListArray, Float64Array, Int32Array,
StringArray,
UInt32Array, UInt64Array,
},
datatypes::Field,
record_batch::RecordBatch,
};
- fn generic_test_math(value: ScalarValue, expected: &str) -> Result<()> {
- // any type works here: we evaluate against a literal of `value`
- let schema = Schema::new(vec![Field::new("a", DataType::Int32,
false)]);
- let columns: Vec<ArrayRef> = vec![Arc::new(Int32Array::from(vec![1]))];
-
- let arg = lit(value);
-
- let expr = create_physical_expr(&BuiltinScalarFunction::Exp, &[arg],
&schema)?;
-
- // type is correct
- assert_eq!(expr.data_type(&schema)?, DataType::Float64);
-
- // evaluate works
- let batch = RecordBatch::try_new(Arc::new(schema.clone()), columns)?;
- let result = expr.evaluate(&batch)?.into_array(batch.num_rows());
-
- // downcast works
- let result = result.as_any().downcast_ref::<Float64Array>().unwrap();
-
- // value is correct
- assert_eq!(result.value(0).to_string(), expected);
-
- Ok(())
+ /// $FUNC function to test
+ /// $ARGS arguments (vec) to pass to function
+ /// $EXPECTED a Result<Option<$EXPECTED_TYPE>> where Result allows testing
errors and Option allows testing Null
+ /// $EXPECTED_TYPE is the expected value type
+ /// $DATA_TYPE is the function to test result type
+ /// $ARRAY_TYPE is the column type after function applied
+ macro_rules! test_function {
+ ($FUNC:ident, $ARGS:expr, $EXPECTED:expr, $EXPECTED_TYPE:ty,
$DATA_TYPE: ident, $ARRAY_TYPE:ident) => {
+ println!("{:?}", BuiltinScalarFunction::$FUNC);
Review comment:
is this `println!` intended?
##########
File path: rust/arrow/src/compute/kernels/bit_length.rs
##########
@@ -0,0 +1,208 @@
+// 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.
+
+//! Defines kernel for length of a string array
+
+use crate::{array::*, buffer::Buffer};
+use crate::{
+ datatypes::DataType,
+ error::{ArrowError, Result},
+};
+use std::sync::Arc;
+
+fn bit_length_string<OffsetSize>(array: &Array, data_type: DataType) ->
ArrayRef
+where
+ OffsetSize: OffsetSizeTrait,
+{
+ // note: offsets are stored as u8, but they can be interpreted as
OffsetSize
+ let offsets = &array.data_ref().buffers()[0];
+ // this is a 30% improvement over iterating over u8s and building
OffsetSize, which
+ // justifies the usage of `unsafe`.
+ let slice: &[OffsetSize] =
+ &unsafe { offsets.typed_data::<OffsetSize>() }[array.offset()..];
+
+ let bit_size = OffsetSize::from_usize(8).unwrap();
+ let lengths = slice
+ .windows(2)
+ .map(|offset| (offset[1] - offset[0]) * bit_size);
+
+ // JUSTIFICATION
+ // Benefit
+ // ~60% speedup
+ // Soundness
+ // `values` is an iterator with a known size.
+ let buffer = unsafe { Buffer::from_trusted_len_iter(lengths) };
+
Review comment:
Isn't this a copy of length, with a single difference, that we multiply
the lengths by `bit_size`?
If that is the case, can we create a generic or something that avoids code
duplication? Copy-pasting code like this is IMO an unnecessary maintenance
burden.
##########
File path: rust/datafusion/src/physical_plan/string_expressions.rs
##########
@@ -115,6 +119,40 @@ where
}
}
+/// Returns number of characters in the string.
+/// character_length_i32('josé') = 4
+pub fn character_length_i32(args: &[ArrayRef]) -> Result<ArrayRef> {
+ let string_array: &GenericStringArray<i32> = args[0]
+ .as_any()
+ .downcast_ref::<GenericStringArray<i32>>()
+ .unwrap();
+
+ // first map is the iterator, second is for the `Option<_>`
+ let result = string_array
+ .iter()
+ .map(|x| x.map(|x: &str| x.graphemes(true).count() as i32))
+ .collect::<Int32Array>();
+
+ Ok(Arc::new(result) as ArrayRef)
+}
+
+/// Returns number of characters in the string.
+/// character_length_i64('josé') = 4
+pub fn character_length_i64(args: &[ArrayRef]) -> Result<ArrayRef> {
Review comment:
I think that this code can be reduced to a single generic. Something
like this (untested):
```rust
pub fn character_length<T: ArrowNativeType>(args: &[ArrayRef]) ->
Result<ArrayRef>
where
T::Native: StringOffsetSizeTrait {
let string_array: &GenericStringArray<T::Native> = args[0]
.as_any()
.downcast_ref::<GenericStringArray<T::Native>>()
.unwrap();
string_array
.iter()
.map(|x| x.map(|x: &str|
T::Native::from_usize(x.graphemes(true).count())).unwrap())
.collect()
}
```
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