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Make regexp_match take Datum pattern input
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@viirya
viirya committed Dec 26, 2023
1 parent 3b3bd60 commit 583fc77
Showing 1 changed file with 209 additions and 22 deletions.
231 changes: 209 additions & 22 deletions arrow-string/src/regexp.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -152,28 +152,7 @@ pub fn regexp_is_match_utf8_scalar<OffsetSize: OffsetSizeTrait>(
Ok(BooleanArray::from(data))
}

/// Extract all groups matched by a regular expression for a given String array.
///
/// Modelled after the Postgres [regexp_match].
///
/// Returns a ListArray of [`GenericStringArray`] with each element containing the leftmost-first
/// match of the corresponding index in `regex_array` to string in `array`
///
/// If there is no match, the list element is NULL.
///
/// If a match is found, and the pattern contains no capturing parenthesized subexpressions,
/// then the list element is a single-element [`GenericStringArray`] containing the substring
/// matching the whole pattern.
///
/// If a match is found, and the pattern contains capturing parenthesized subexpressions, then the
/// list element is a [`GenericStringArray`] whose n'th element is the substring matching
/// the n'th capturing parenthesized subexpression of the pattern.
///
/// The flags parameter is an optional text string containing zero or more single-letter flags
/// that change the function's behavior.
///
/// [regexp_match]: https://www.postgresql.org/docs/current/functions-matching.html#FUNCTIONS-POSIX-REGEXP
pub fn regexp_match<OffsetSize: OffsetSizeTrait>(
fn regexp_array_match<OffsetSize: OffsetSizeTrait>(
array: &GenericStringArray<OffsetSize>,
regex_array: &GenericStringArray<OffsetSize>,
flags_array: Option<&GenericStringArray<OffsetSize>>,
Expand Down Expand Up @@ -248,6 +227,214 @@ pub fn regexp_match<OffsetSize: OffsetSizeTrait>(
Ok(Arc::new(list_builder.finish()))
}

fn get_scalar_pattern_flag<'a, OffsetSize: OffsetSizeTrait>(
regex_array: &'a dyn Array,
flag_array: Option<&'a dyn Array>,
) -> (&'a str, Option<&'a str>) {
let regex = regex_array
.as_any()
.downcast_ref::<GenericStringArray<OffsetSize>>()
.expect("Unable to downcast to StringArray/LargeStringArray");
let regex = regex.value(0);

if flag_array.is_some() {
let flag = flag_array
.unwrap()
.as_any()
.downcast_ref::<GenericStringArray<OffsetSize>>()
.expect("Unable to downcast to StringArray/LargeStringArray");

if flag.is_valid(0) {
let flag = flag.value(0);
(regex, Some(flag))
} else {
(regex, None)
}
} else {
(regex, None)
}
}

fn regexp_scalar_match<OffsetSize: OffsetSizeTrait>(
array: &dyn Array,
regex: Option<&Regex>,
) -> std::result::Result<ArrayRef, ArrowError> {
if regex.is_none() {}

let builder: GenericStringBuilder<OffsetSize> = GenericStringBuilder::with_capacity(0, 0);
let mut list_builder = ListBuilder::new(builder);

let array = array
.as_any()
.downcast_ref::<GenericStringArray<OffsetSize>>()
.expect("Unable to downcast to StringArray/LargeStringArray");

let regex = regex.unwrap();

array
.iter()
.map(|value| {
match value {
// Required for Postgres compatibility:
// SELECT regexp_match('foobarbequebaz', ''); = {""}
Some(_) if regex.as_str() == "" => {
list_builder.values().append_value("");
list_builder.append(true);
}
Some(value) => match regex.captures(value) {
Some(caps) => {
let mut iter = caps.iter();
if caps.len() > 1 {
iter.next();
}
for m in iter.flatten() {
list_builder.values().append_value(m.as_str());
}

list_builder.append(true);
}
None => list_builder.append(false),
},
_ => list_builder.append(false),
}
Ok(())
})
.collect::<Result<Vec<()>, ArrowError>>()?;

Ok(Arc::new(list_builder.finish()))
}

/// Extract all groups matched by a regular expression for a given String array.
///
/// Modelled after the Postgres [regexp_match].
///
/// Returns a ListArray of [`GenericStringArray`] with each element containing the leftmost-first
/// match of the corresponding index in `regex_array` to string in `array`
///
/// If there is no match, the list element is NULL.
///
/// If a match is found, and the pattern contains no capturing parenthesized subexpressions,
/// then the list element is a single-element [`GenericStringArray`] containing the substring
/// matching the whole pattern.
///
/// If a match is found, and the pattern contains capturing parenthesized subexpressions, then the
/// list element is a [`GenericStringArray`] whose n'th element is the substring matching
/// the n'th capturing parenthesized subexpression of the pattern.
///
/// The flags parameter is an optional text string containing zero or more single-letter flags
/// that change the function's behavior.
///
/// [regexp_match]: https://www.postgresql.org/docs/current/functions-matching.html#FUNCTIONS-POSIX-REGEXP
pub fn regexp_match(
array: &dyn Datum,
regex_array: &dyn Datum,
flags_array: Option<&dyn Datum>,
) -> std::result::Result<ArrayRef, ArrowError> {
let (lhs, is_lhs_scalar) = array.get();
let (rhs, is_rhs_scalar) = regex_array.get();

let (flags, is_flags_scalar) = match flags_array {
Some(flags) => {
let (flags, is_flags_scalar) = flags.get();
(Some(flags), Some(is_flags_scalar))
}
None => (None, None),
};

if is_lhs_scalar {
return Err(ArrowError::ComputeError(format!(
"regexp_match() requires array to be either Utf8 or LargeUtf8 array instead of scalar"
)));
}

if is_flags_scalar.is_some() && is_rhs_scalar != is_flags_scalar.unwrap() {
return Err(ArrowError::ComputeError(format!(
"regexp_match() requires both pattern and flags to be either scalar or array"
)));
}

if flags_array.is_some() && rhs.data_type() != flags.unwrap().data_type() {
return Err(ArrowError::ComputeError(format!(
"regexp_match() requires both pattern and flags to be either string or largestring"
)));
}

if is_rhs_scalar {
// Regex and flag is scalars
let (regex, flag) = match rhs.data_type() {
DataType::Utf8 => get_scalar_pattern_flag::<i32>(rhs, flags),
DataType::LargeUtf8 => get_scalar_pattern_flag::<i64>(rhs, flags),
_ => {
return Err(ArrowError::ComputeError(format!(
"regexp_match() requires pattern to be either Utf8 or LargeUtf8"
)));
}
};

let pattern = if let Some(flag) = flag {
format!("(?{regex}){flag}")
} else {
regex.to_string()
};

let re = Regex::new(pattern.as_str()).map_err(|e| {
ArrowError::ComputeError(format!("Regular expression did not compile: {e:?}"))
})?;

match lhs.data_type() {
DataType::Utf8 => regexp_scalar_match::<i32>(lhs, Some(&re)),
DataType::LargeUtf8 => regexp_scalar_match::<i64>(lhs, Some(&re)),
_ => {
return Err(ArrowError::ComputeError(format!(
"regexp_match() requires array to be either Utf8 or LargeUtf8"
)));
}
}
} else {
match rhs.data_type() {
DataType::Utf8 => {
let array = lhs
.as_any()
.downcast_ref::<GenericStringArray<i32>>()
.expect("Unable to downcast to StringArray/LargeStringArray");
let regex_array = rhs
.as_any()
.downcast_ref::<GenericStringArray<i32>>()
.expect("Unable to downcast to StringArray/LargeStringArray");
let flags_array = flags.map(|flags| {
flags
.as_any()
.downcast_ref::<GenericStringArray<i32>>()
.expect("Unable to downcast to StringArray/LargeStringArray")
});
regexp_array_match(array, regex_array, flags_array)
}
DataType::LargeUtf8 => {
let array = lhs
.as_any()
.downcast_ref::<GenericStringArray<i64>>()
.expect("Unable to downcast to StringArray/LargeStringArray");
let regex_array = rhs
.as_any()
.downcast_ref::<GenericStringArray<i64>>()
.expect("Unable to downcast to StringArray/LargeStringArray");
let flags_array = flags.map(|flags| {
flags
.as_any()
.downcast_ref::<GenericStringArray<i64>>()
.expect("Unable to downcast to StringArray/LargeStringArray")
});
regexp_array_match(array, regex_array, flags_array)
}
_ => {
return Err(ArrowError::ComputeError(format!(
"regexp_match() requires pattern to be either Utf8 or LargeUtf8"
)));
}
}
}
}

#[cfg(test)]
mod tests {
use super::*;
Expand Down

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