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ARROW-11123: [Rust] Use cast kernel to simplify csv parser #9090

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8596977
Use cast kernel to simplify csv parser
Dandandan Jan 4, 2021
d5b438c
Fmt
Dandandan Jan 4, 2021
d83ae2d
Use iterator for date32
Dandandan Jan 4, 2021
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29 changes: 15 additions & 14 deletions rust/arrow/src/compute/kernels/cast.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -378,20 +378,21 @@ pub fn cast(array: &ArrayRef, to_type: &DataType) -> Result<ArrayRef> {
Date32(DateUnit::Day) => {
use chrono::Datelike;
let string_array = array.as_any().downcast_ref::<StringArray>().unwrap();
let mut builder = PrimitiveBuilder::<Date32Type>::new(string_array.len());
for i in 0..string_array.len() {
if string_array.is_null(i) {
builder.append_null()?;
} else {
match string_array.value(i).parse::<chrono::NaiveDate>() {
Ok(date) => builder.append_value(
date.num_days_from_ce() - EPOCH_DAYS_FROM_CE,
)?,
Err(_) => builder.append_null()?, // not a valid date
};
}
}
Ok(Arc::new(builder.finish()) as ArrayRef)
let array = (0..string_array.len())
.map(|i| {
if string_array.is_null(i) {
None
} else {
match string_array.value(i).parse::<chrono::NaiveDate>() {
Ok(date) => {
Some(date.num_days_from_ce() - EPOCH_DAYS_FROM_CE)
}
Err(_) => None, // not a valid date
}
}
})
.collect::<Date32Array>();
Ok(Arc::new(array) as ArrayRef)
}
Date64(DateUnit::Millisecond) => {
let string_array = array.as_any().downcast_ref::<StringArray>().unwrap();
Expand Down
236 changes: 22 additions & 214 deletions rust/arrow/src/csv/reader.rs
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Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -51,10 +51,13 @@ use std::sync::Arc;

use csv as csv_crate;

use crate::array::{ArrayRef, BooleanArray, PrimitiveArray, StringArray};
use crate::datatypes::*;
use crate::error::{ArrowError, Result};
use crate::record_batch::RecordBatch;
use crate::{
array::{ArrayRef, BooleanArray, StringArray},
compute::cast,
};

use self::csv_crate::{ByteRecord, StringRecord};

Expand Down Expand Up @@ -413,51 +416,24 @@ fn parse(
let field = &fields[i];
match field.data_type() {
&DataType::Boolean => build_boolean_array(line_number, rows, i),
&DataType::Int8 => {
build_primitive_array::<Int8Type>(line_number, rows, i)
}
&DataType::Int16 => {
build_primitive_array::<Int16Type>(line_number, rows, i)
}
&DataType::Int32 => {
build_primitive_array::<Int32Type>(line_number, rows, i)
}
&DataType::Int64 => {
build_primitive_array::<Int64Type>(line_number, rows, i)
}
&DataType::UInt8 => {
build_primitive_array::<UInt8Type>(line_number, rows, i)
}
&DataType::UInt16 => {
build_primitive_array::<UInt16Type>(line_number, rows, i)
}
&DataType::UInt32 => {
build_primitive_array::<UInt32Type>(line_number, rows, i)
}
&DataType::UInt64 => {
build_primitive_array::<UInt64Type>(line_number, rows, i)
}
&DataType::Float32 => {
build_primitive_array::<Float32Type>(line_number, rows, i)
}
&DataType::Float64 => {
build_primitive_array::<Float64Type>(line_number, rows, i)
}
&DataType::Date32(_) => {
build_primitive_array::<Date32Type>(line_number, rows, i)
}
&DataType::Date64(_) => {
build_primitive_array::<Date64Type>(line_number, rows, i)
}
&DataType::Timestamp(TimeUnit::Microsecond, _) => {
build_primitive_array::<TimestampMicrosecondType>(
line_number,
rows,
i,
)
}
&DataType::Timestamp(TimeUnit::Nanosecond, _) => {
build_primitive_array::<TimestampNanosecondType>(line_number, rows, i)
&DataType::Int8
| &DataType::Int16
| &DataType::Int32
| &DataType::Int64
| &DataType::UInt8
| &DataType::UInt16
| &DataType::UInt32
| &DataType::UInt64
| &DataType::Timestamp(TimeUnit::Nanosecond, _)
| &DataType::Timestamp(TimeUnit::Microsecond, _)
| &DataType::Date64(_)
| &DataType::Date32(_)
| &DataType::Float64
| &DataType::Float32 => {
let string_array = Arc::new(
rows.iter().map(|row| row.get(i)).collect::<StringArray>(),
) as ArrayRef;
cast(&string_array, field.data_type())
}
&DataType::Utf8 => Ok(Arc::new(
rows.iter().map(|row| row.get(i)).collect::<StringArray>(),
Expand All @@ -478,97 +454,6 @@ fn parse(
arrays.and_then(|arr| RecordBatch::try_new(projected_schema, arr))
}

/// Specialized parsing implementations
trait Parser: ArrowPrimitiveType {
fn parse(string: &str) -> Option<Self::Native> {
string.parse::<Self::Native>().ok()
}
}

impl Parser for Float32Type {
fn parse(string: &str) -> Option<f32> {
lexical_core::parse(string.as_bytes()).ok()
}
}
impl Parser for Float64Type {
fn parse(string: &str) -> Option<f64> {
lexical_core::parse(string.as_bytes()).ok()
}
}

impl Parser for UInt64Type {}

impl Parser for UInt32Type {}

impl Parser for UInt16Type {}

impl Parser for UInt8Type {}

impl Parser for Int64Type {}

impl Parser for Int32Type {}

impl Parser for Int16Type {}

impl Parser for Int8Type {}

/// Number of days between 0001-01-01 and 1970-01-01
const EPOCH_DAYS_FROM_CE: i32 = 719_163;

impl Parser for Date32Type {
fn parse(string: &str) -> Option<i32> {
use chrono::Datelike;

match Self::DATA_TYPE {
DataType::Date32(DateUnit::Day) => {
let date = string.parse::<chrono::NaiveDate>().ok()?;
Self::Native::from_i32(date.num_days_from_ce() - EPOCH_DAYS_FROM_CE)
}
_ => None,
}
}
}

impl Parser for Date64Type {
fn parse(string: &str) -> Option<i64> {
match Self::DATA_TYPE {
DataType::Date64(DateUnit::Millisecond) => {
let date_time = string.parse::<chrono::NaiveDateTime>().ok()?;
Self::Native::from_i64(date_time.timestamp_millis())
}
_ => None,
}
}
}

impl Parser for TimestampNanosecondType {
fn parse(string: &str) -> Option<i64> {
match Self::DATA_TYPE {
DataType::Timestamp(TimeUnit::Nanosecond, None) => {
let date_time = string.parse::<chrono::NaiveDateTime>().ok()?;
Self::Native::from_i64(date_time.timestamp_nanos())
}
_ => None,
}
}
}

impl Parser for TimestampMicrosecondType {
fn parse(string: &str) -> Option<i64> {
match Self::DATA_TYPE {
DataType::Timestamp(TimeUnit::Microsecond, None) => {
let date_time = string.parse::<chrono::NaiveDateTime>().ok()?;
Self::Native::from_i64(date_time.timestamp_nanos() / 1000)
}
_ => None,
}
}
}

fn parse_item<T: Parser>(string: &str) -> Option<T::Native> {
T::parse(string)
}

fn parse_bool(string: &str) -> Option<bool> {
if string.eq_ignore_ascii_case("false") {
Some(false)
Expand All @@ -579,40 +464,6 @@ fn parse_bool(string: &str) -> Option<bool> {
}
}

// parses a specific column (col_idx) into an Arrow Array.
fn build_primitive_array<T: ArrowPrimitiveType + Parser>(
line_number: usize,
rows: &[StringRecord],
col_idx: usize,
) -> Result<ArrayRef> {
rows.iter()
.enumerate()
.map(|(row_index, row)| {
match row.get(col_idx) {
Some(s) => {
if s.is_empty() {
return Ok(None);
}

let parsed = parse_item::<T>(s);
match parsed {
Some(e) => Ok(Some(e)),
None => Err(ArrowError::ParseError(format!(
// TODO: we should surface the underlying error here.
"Error while parsing value {} for column {} at line {}",
s,
col_idx,
line_number + row_index
))),
}
}
None => Ok(None),
}
})
.collect::<Result<PrimitiveArray<T>>>()
.map(|e| Arc::new(e) as ArrayRef)
}

// parses a specific column (col_idx) into an Arrow Array.
fn build_boolean_array(
line_number: usize,
Expand Down Expand Up @@ -1098,30 +949,6 @@ mod tests {
);
}

#[test]
fn parse_date32() {
assert_eq!(parse_item::<Date32Type>("1970-01-01").unwrap(), 0);
assert_eq!(parse_item::<Date32Type>("2020-03-15").unwrap(), 18336);
assert_eq!(parse_item::<Date32Type>("1945-05-08").unwrap(), -9004);
}

#[test]
fn parse_date64() {
assert_eq!(parse_item::<Date64Type>("1970-01-01T00:00:00").unwrap(), 0);
assert_eq!(
parse_item::<Date64Type>("2018-11-13T17:11:10").unwrap(),
1542129070000
);
assert_eq!(
parse_item::<Date64Type>("2018-11-13T17:11:10.011").unwrap(),
1542129070011
);
assert_eq!(
parse_item::<Date64Type>("1900-02-28T12:34:56").unwrap(),
-2203932304000
);
}

#[test]
fn test_infer_schema_from_multiple_files() -> Result<()> {
let mut csv1 = NamedTempFile::new()?;
Expand Down Expand Up @@ -1230,23 +1057,4 @@ mod tests {
assert_eq!(None, parse_bool("F"));
assert_eq!(None, parse_bool(""));
}

#[test]
fn test_parsing_float() {
assert_eq!(Some(12.34), parse_item::<Float64Type>("12.34"));
assert_eq!(Some(-12.34), parse_item::<Float64Type>("-12.34"));
assert_eq!(Some(12.0), parse_item::<Float64Type>("12"));
assert_eq!(Some(0.0), parse_item::<Float64Type>("0"));
assert!(parse_item::<Float64Type>("nan").unwrap().is_nan());
assert!(parse_item::<Float64Type>("NaN").unwrap().is_nan());
assert!(parse_item::<Float64Type>("inf").unwrap().is_infinite());
assert!(parse_item::<Float64Type>("inf").unwrap().is_sign_positive());
assert!(parse_item::<Float64Type>("-inf").unwrap().is_infinite());
assert!(parse_item::<Float64Type>("-inf")
.unwrap()
.is_sign_negative());
assert_eq!(None, parse_item::<Float64Type>(""));
assert_eq!(None, parse_item::<Float64Type>("dd"));
assert_eq!(None, parse_item::<Float64Type>("12.34.56"));
}
}