viirya commented on code in PR #4088:
URL: https://github.com/apache/arrow-rs/pull/4088#discussion_r1169132139
##########
arrow-cast/src/cast.rs:
##########
@@ -2081,66 +2081,166 @@ impl DecimalCast for i256 {
}
}
-fn cast_decimal_to_decimal<I, O>(
- array: &PrimitiveArray<I>,
- input_scale: i8,
+fn cast_decimal_to_decimal_error<I, O>(
output_precision: u8,
output_scale: i8,
- cast_options: &CastOptions,
-) -> Result<ArrayRef, ArrowError>
+) -> impl Fn(<I as ArrowPrimitiveType>::Native) -> ArrowError
where
I: DecimalType,
O: DecimalType,
I::Native: DecimalCast + ArrowNativeTypeOp,
O::Native: DecimalCast + ArrowNativeTypeOp,
{
- let error = |x| {
+ move |x: I::Native| {
ArrowError::CastError(format!(
"Cannot cast to {}({}, {}). Overflowing on {:?}",
O::PREFIX,
output_precision,
output_scale,
x
))
- };
+ }
+}
- let array: PrimitiveArray<O> = if input_scale > output_scale {
- let div = I::Native::from_decimal(10_i128)
- .unwrap()
- .pow_checked((input_scale - output_scale) as u32)?;
+fn convert_to_smaller_equal_scale_decimal<I, O>(
+ array: &PrimitiveArray<I>,
+ input_scale: i8,
+ output_precision: u8,
+ output_scale: i8,
+ cast_options: &CastOptions,
+) -> Result<PrimitiveArray<O>, ArrowError>
+where
+ I: DecimalType,
+ O: DecimalType,
+ I::Native: DecimalCast + ArrowNativeTypeOp,
+ O::Native: DecimalCast + ArrowNativeTypeOp,
+{
+ let error = cast_decimal_to_decimal_error::<I, O>(output_precision,
output_scale);
+ let div = I::Native::from_decimal(10_i128)
+ .unwrap()
+ .pow_checked((input_scale - output_scale) as u32)?;
- let half = div.div_wrapping(I::Native::from_usize(2).unwrap());
- let half_neg = half.neg_wrapping();
+ let half = div.div_wrapping(I::Native::from_usize(2).unwrap());
+ let half_neg = half.neg_wrapping();
- let f = |x: I::Native| {
- // div is >= 10 and so this cannot overflow
- let d = x.div_wrapping(div);
- let r = x.mod_wrapping(div);
+ let f = |x: I::Native| {
+ // div is >= 10 and so this cannot overflow
+ let d = x.div_wrapping(div);
+ let r = x.mod_wrapping(div);
- // Round result
- let adjusted = match x >= I::Native::ZERO {
- true if r >= half => d.add_wrapping(I::Native::ONE),
- false if r <= half_neg => d.sub_wrapping(I::Native::ONE),
- _ => d,
- };
- O::Native::from_decimal(adjusted)
+ // Round result
+ let adjusted = match x >= I::Native::ZERO {
+ true if r >= half => d.add_wrapping(I::Native::ONE),
+ false if r <= half_neg => d.sub_wrapping(I::Native::ONE),
+ _ => d,
};
+ O::Native::from_decimal(adjusted)
+ };
- match cast_options.safe {
- true => array.unary_opt(f),
- false => array.try_unary(|x| f(x).ok_or_else(|| error(x)))?,
- }
- } else {
- let mul = O::Native::from_decimal(10_i128)
- .unwrap()
- .pow_checked((output_scale - input_scale) as u32)?;
+ Ok(match cast_options.safe {
+ true => array.unary_opt(f),
+ false => array.try_unary(|x| f(x).ok_or_else(|| error(x)))?,
+ })
+}
- let f = |x| O::Native::from_decimal(x).and_then(|x|
x.mul_checked(mul).ok());
+fn convert_to_bigger_scale_decimal<I, O>(
+ array: &PrimitiveArray<I>,
+ input_scale: i8,
+ output_precision: u8,
+ output_scale: i8,
+ cast_options: &CastOptions,
+) -> Result<PrimitiveArray<O>, ArrowError>
+where
+ I: DecimalType,
+ O: DecimalType,
+ I::Native: DecimalCast + ArrowNativeTypeOp,
+ O::Native: DecimalCast + ArrowNativeTypeOp,
+{
+ let error = cast_decimal_to_decimal_error::<I, O>(output_precision,
output_scale);
+ let mul = O::Native::from_decimal(10_i128)
+ .unwrap()
+ .pow_checked((output_scale - input_scale) as u32)?;
- match cast_options.safe {
- true => array.unary_opt(f),
- false => array.try_unary(|x| f(x).ok_or_else(|| error(x)))?,
+ let f = |x| O::Native::from_decimal(x).and_then(|x|
x.mul_checked(mul).ok());
+
+ Ok(match cast_options.safe {
+ true => array.unary_opt(f),
+ false => array.try_unary(|x| f(x).ok_or_else(|| error(x)))?,
+ })
+}
+
+// Only support one type of decimal cast operations
+fn cast_decimal_to_decimal_same_type<T>(
+ array: &PrimitiveArray<T>,
+ input_scale: i8,
+ output_precision: u8,
+ output_scale: i8,
+ cast_options: &CastOptions,
+) -> Result<ArrayRef, ArrowError>
+where
+ T: DecimalType,
+ T::Native: DecimalCast + ArrowNativeTypeOp,
+{
+ let array: PrimitiveArray<T> = match input_scale.cmp(&output_scale) {
+ Ordering::Equal => {
+ // the scale doesn't change, the native value don't need to be
changed
+ array.clone()
}
+ Ordering::Greater => convert_to_smaller_equal_scale_decimal::<T, T>(
+ array,
+ input_scale,
+ output_precision,
+ output_scale,
+ cast_options,
+ )?,
+ Ordering::Less => {
+ // input_scale < output_scale
+ convert_to_bigger_scale_decimal::<T, T>(
+ array,
+ input_scale,
+ output_precision,
+ output_scale,
+ cast_options,
+ )?
+ }
+ };
+
+ Ok(Arc::new(array.with_precision_and_scale(
+ output_precision,
+ output_scale,
+ )?))
+}
+
+// Support two different types of decimal cast operations
+fn cast_decimal_to_decimal<I, O>(
+ array: &PrimitiveArray<I>,
+ input_scale: i8,
+ output_precision: u8,
+ output_scale: i8,
+ cast_options: &CastOptions,
+) -> Result<ArrayRef, ArrowError>
+where
+ I: DecimalType,
+ O: DecimalType,
+ I::Native: DecimalCast + ArrowNativeTypeOp,
+ O::Native: DecimalCast + ArrowNativeTypeOp,
+{
+ let array: PrimitiveArray<O> = if input_scale > output_scale {
+ convert_to_smaller_equal_scale_decimal::<I, O>(
Review Comment:
```suggestion
convert_to_smaller_scale_decimal::<I, O>(
```
##########
arrow-cast/src/cast.rs:
##########
@@ -2081,66 +2081,166 @@ impl DecimalCast for i256 {
}
}
-fn cast_decimal_to_decimal<I, O>(
- array: &PrimitiveArray<I>,
- input_scale: i8,
+fn cast_decimal_to_decimal_error<I, O>(
output_precision: u8,
output_scale: i8,
- cast_options: &CastOptions,
-) -> Result<ArrayRef, ArrowError>
+) -> impl Fn(<I as ArrowPrimitiveType>::Native) -> ArrowError
where
I: DecimalType,
O: DecimalType,
I::Native: DecimalCast + ArrowNativeTypeOp,
O::Native: DecimalCast + ArrowNativeTypeOp,
{
- let error = |x| {
+ move |x: I::Native| {
ArrowError::CastError(format!(
"Cannot cast to {}({}, {}). Overflowing on {:?}",
O::PREFIX,
output_precision,
output_scale,
x
))
- };
+ }
+}
- let array: PrimitiveArray<O> = if input_scale > output_scale {
- let div = I::Native::from_decimal(10_i128)
- .unwrap()
- .pow_checked((input_scale - output_scale) as u32)?;
+fn convert_to_smaller_equal_scale_decimal<I, O>(
+ array: &PrimitiveArray<I>,
+ input_scale: i8,
+ output_precision: u8,
+ output_scale: i8,
+ cast_options: &CastOptions,
+) -> Result<PrimitiveArray<O>, ArrowError>
+where
+ I: DecimalType,
+ O: DecimalType,
+ I::Native: DecimalCast + ArrowNativeTypeOp,
+ O::Native: DecimalCast + ArrowNativeTypeOp,
+{
+ let error = cast_decimal_to_decimal_error::<I, O>(output_precision,
output_scale);
+ let div = I::Native::from_decimal(10_i128)
+ .unwrap()
+ .pow_checked((input_scale - output_scale) as u32)?;
- let half = div.div_wrapping(I::Native::from_usize(2).unwrap());
- let half_neg = half.neg_wrapping();
+ let half = div.div_wrapping(I::Native::from_usize(2).unwrap());
+ let half_neg = half.neg_wrapping();
- let f = |x: I::Native| {
- // div is >= 10 and so this cannot overflow
- let d = x.div_wrapping(div);
- let r = x.mod_wrapping(div);
+ let f = |x: I::Native| {
+ // div is >= 10 and so this cannot overflow
+ let d = x.div_wrapping(div);
+ let r = x.mod_wrapping(div);
- // Round result
- let adjusted = match x >= I::Native::ZERO {
- true if r >= half => d.add_wrapping(I::Native::ONE),
- false if r <= half_neg => d.sub_wrapping(I::Native::ONE),
- _ => d,
- };
- O::Native::from_decimal(adjusted)
+ // Round result
+ let adjusted = match x >= I::Native::ZERO {
+ true if r >= half => d.add_wrapping(I::Native::ONE),
+ false if r <= half_neg => d.sub_wrapping(I::Native::ONE),
+ _ => d,
};
+ O::Native::from_decimal(adjusted)
+ };
- match cast_options.safe {
- true => array.unary_opt(f),
- false => array.try_unary(|x| f(x).ok_or_else(|| error(x)))?,
- }
- } else {
- let mul = O::Native::from_decimal(10_i128)
- .unwrap()
- .pow_checked((output_scale - input_scale) as u32)?;
+ Ok(match cast_options.safe {
+ true => array.unary_opt(f),
+ false => array.try_unary(|x| f(x).ok_or_else(|| error(x)))?,
+ })
+}
- let f = |x| O::Native::from_decimal(x).and_then(|x|
x.mul_checked(mul).ok());
+fn convert_to_bigger_scale_decimal<I, O>(
+ array: &PrimitiveArray<I>,
+ input_scale: i8,
+ output_precision: u8,
+ output_scale: i8,
+ cast_options: &CastOptions,
+) -> Result<PrimitiveArray<O>, ArrowError>
+where
+ I: DecimalType,
+ O: DecimalType,
+ I::Native: DecimalCast + ArrowNativeTypeOp,
+ O::Native: DecimalCast + ArrowNativeTypeOp,
+{
+ let error = cast_decimal_to_decimal_error::<I, O>(output_precision,
output_scale);
+ let mul = O::Native::from_decimal(10_i128)
+ .unwrap()
+ .pow_checked((output_scale - input_scale) as u32)?;
- match cast_options.safe {
- true => array.unary_opt(f),
- false => array.try_unary(|x| f(x).ok_or_else(|| error(x)))?,
+ let f = |x| O::Native::from_decimal(x).and_then(|x|
x.mul_checked(mul).ok());
+
+ Ok(match cast_options.safe {
+ true => array.unary_opt(f),
+ false => array.try_unary(|x| f(x).ok_or_else(|| error(x)))?,
+ })
+}
+
+// Only support one type of decimal cast operations
+fn cast_decimal_to_decimal_same_type<T>(
+ array: &PrimitiveArray<T>,
+ input_scale: i8,
+ output_precision: u8,
+ output_scale: i8,
+ cast_options: &CastOptions,
+) -> Result<ArrayRef, ArrowError>
+where
+ T: DecimalType,
+ T::Native: DecimalCast + ArrowNativeTypeOp,
+{
+ let array: PrimitiveArray<T> = match input_scale.cmp(&output_scale) {
+ Ordering::Equal => {
+ // the scale doesn't change, the native value don't need to be
changed
+ array.clone()
}
+ Ordering::Greater => convert_to_smaller_equal_scale_decimal::<T, T>(
+ array,
+ input_scale,
+ output_precision,
+ output_scale,
+ cast_options,
+ )?,
+ Ordering::Less => {
+ // input_scale < output_scale
+ convert_to_bigger_scale_decimal::<T, T>(
+ array,
+ input_scale,
+ output_precision,
+ output_scale,
+ cast_options,
+ )?
+ }
+ };
+
+ Ok(Arc::new(array.with_precision_and_scale(
+ output_precision,
+ output_scale,
+ )?))
+}
+
+// Support two different types of decimal cast operations
+fn cast_decimal_to_decimal<I, O>(
+ array: &PrimitiveArray<I>,
+ input_scale: i8,
+ output_precision: u8,
+ output_scale: i8,
+ cast_options: &CastOptions,
+) -> Result<ArrayRef, ArrowError>
+where
+ I: DecimalType,
+ O: DecimalType,
+ I::Native: DecimalCast + ArrowNativeTypeOp,
+ O::Native: DecimalCast + ArrowNativeTypeOp,
+{
+ let array: PrimitiveArray<O> = if input_scale > output_scale {
+ convert_to_smaller_equal_scale_decimal::<I, O>(
+ array,
+ input_scale,
+ output_precision,
+ output_scale,
+ cast_options,
+ )?
+ } else {
+ convert_to_bigger_scale_decimal::<I, O>(
Review Comment:
```suggestion
convert_to_bigger_or_equal_scale_decimal::<I, O>(
```
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