jorgecarleitao commented on a change in pull request #8640:
URL: https://github.com/apache/arrow/pull/8640#discussion_r524410551
##
File path: rust/arrow/src/array/builder.rs
##
@@ -1882,6 +1975,67 @@ impl FixedSizeBinaryBuilder {
}
}
+impl DecimalBuilder {
+/// Creates a new `BinaryBuilder`, `capacity` is the number of bytes in
the values
+/// array
+pub fn new(capacity: usize, precision: usize, scale: usize) -> Self {
+let values_builder = UInt8Builder::new(capacity);
+let byte_width = DecimalArray::calc_fixed_byte_size(precision);
+Self {
+builder: FixedSizeListBuilder::new(values_builder, byte_width),
+precision,
+scale,
+}
+}
+
+/// Appends a byte slice into the builder.
+///
+/// Automatically calls the `append` method to delimit the slice appended
in as a
+/// distinct array element.
+pub fn append_value( self, value: i128) -> Result<()> {
+let value_as_bytes = Self::from_i128_to_fixed_size_bytes(
+value,
+self.builder.value_length() as usize,
+)?;
+if self.builder.value_length() != value_as_bytes.len() as i32 {
+return Err(ArrowError::InvalidArgumentError(
+"Byte slice does not have the same length as DecimalBuilder
value lengths".to_string()
+));
+}
+self.builder
+.values()
+.append_slice(value_as_bytes.as_slice())?;
+self.builder.append(true)
+}
+
+fn from_i128_to_fixed_size_bytes(v: i128, size: usize) -> Result> {
+if size > 16 {
+return Err(ArrowError::InvalidArgumentError(
+"DecimalBuilder only supports values up to 16
bytes.".to_string(),
+));
+}
+let res = v.to_be_bytes();
+let start_byte = 16 - size;
+Ok(res[start_byte..16].to_vec())
+}
+
+/// Append a null value to the array.
+pub fn append_null( self) -> Result<()> {
+let length: usize = self.builder.value_length() as usize;
+self.builder.values().append_slice(![0u8; length][..])?;
Review comment:
```suggestion
self.builder.values().append_slice(&[0u8; length])?;
```
##
File path: rust/arrow/src/array/equal/mod.rs
##
@@ -604,6 +613,76 @@ mod tests {
test_equal(_slice, _slice, true);
}
+fn create_decimal_array(data: &[Option]) -> ArrayDataRef {
+let mut builder = DecimalBuilder::new(20, 23, 6);
+
+for d in data {
+if let Some(v) = d {
+builder.append_value(*v).unwrap();
+} else {
+builder.append_null().unwrap();
+}
+}
+builder.finish().data()
+}
+
+#[test]
+fn test_decimal_equal() {
+let a = create_decimal_array(&[Some(8_887_000_000),
Some(-8_887_000_000)]);
+let b = create_decimal_array(&[Some(8_887_000_000),
Some(-8_887_000_000)]);
+test_equal(a.as_ref(), b.as_ref(), true);
+
+let b = create_decimal_array(&[Some(15_887_000_000),
Some(-8_887_000_000)]);
+test_equal(a.as_ref(), b.as_ref(), false);
+}
+
+// Test the case where null_count > 0
+#[test]
+fn test_decimal_null() {
+let a = create_decimal_array(&[Some(8_887_000_000), None,
Some(-8_887_000_000)]);
+let b = create_decimal_array(&[Some(8_887_000_000), None,
Some(-8_887_000_000)]);
+test_equal(a.as_ref(), b.as_ref(), true);
+
+let b = create_decimal_array(&[Some(8_887_000_000),
Some(-8_887_000_000), None]);
+test_equal(a.as_ref(), b.as_ref(), false);
+
+let b = create_decimal_array(&[Some(15_887_000_000), None,
Some(-8_887_000_000)]);
+test_equal(a.as_ref(), b.as_ref(), false);
+}
+
+#[test]
+fn test_decimal_offsets() {
+// Test the case where offset != 0
+let a = create_decimal_array(&[
+Some(8_887_000_000),
+None,
+None,
+Some(-8_887_000_000),
+None,
+None,
+]);
+let b = create_decimal_array(&[
+Some(8_887_000_000),
+None,
+None,
+Some(15_887_000_000),
+None,
+None,
+]);
+
+let a_slice = a.slice(0, 3);
+let b_slice = b.slice(0, 3);
+test_equal(_slice, _slice, true);
+
+let a_slice = a.slice(0, 5);
+let b_slice = b.slice(0, 5);
+test_equal(_slice, _slice, false);
+
+let a_slice = a.slice(4, 1);
+let b_slice = b.slice(4, 1);
+test_equal(_slice, _slice, true);
Review comment:
Could we add a case with a non-zero start slice whose test is not equal
(non-zero slices are the tricky ones due to the offset calculation.
This is an automated message from the Apache Git Service.
To
