polars_io/csv/read/parser.rs
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use std::path::Path;
use memchr::memchr2_iter;
use num_traits::Pow;
use polars_core::prelude::*;
use polars_core::{config, POOL};
use polars_error::feature_gated;
use polars_utils::index::Bounded;
use rayon::prelude::*;
use super::buffer::Buffer;
use super::options::{CommentPrefix, NullValuesCompiled};
use super::splitfields::SplitFields;
use super::utils::get_file_chunks;
use crate::path_utils::is_cloud_url;
use crate::utils::compression::maybe_decompress_bytes;
/// Read the number of rows without parsing columns
/// useful for count(*) queries
pub fn count_rows(
path: &Path,
separator: u8,
quote_char: Option<u8>,
comment_prefix: Option<&CommentPrefix>,
eol_char: u8,
has_header: bool,
) -> PolarsResult<usize> {
let file = if is_cloud_url(path) || config::force_async() {
feature_gated!("cloud", {
crate::file_cache::FILE_CACHE
.get_entry(path.to_str().unwrap())
// Safety: This was initialized by schema inference.
.unwrap()
.try_open_assume_latest()?
})
} else {
polars_utils::open_file(path)?
};
let mmap = unsafe { memmap::Mmap::map(&file).unwrap() };
let owned = &mut vec![];
let reader_bytes = maybe_decompress_bytes(mmap.as_ref(), owned)?;
count_rows_from_slice(
reader_bytes,
separator,
quote_char,
comment_prefix,
eol_char,
has_header,
)
}
/// Read the number of rows without parsing columns
/// useful for count(*) queries
pub fn count_rows_from_slice(
mut bytes: &[u8],
separator: u8,
quote_char: Option<u8>,
comment_prefix: Option<&CommentPrefix>,
eol_char: u8,
has_header: bool,
) -> PolarsResult<usize> {
for _ in 0..bytes.len() {
if bytes[0] != eol_char {
break;
}
bytes = &bytes[1..];
}
const MIN_ROWS_PER_THREAD: usize = 1024;
let max_threads = POOL.current_num_threads();
// Determine if parallelism is beneficial and how many threads
let n_threads = get_line_stats(
bytes,
MIN_ROWS_PER_THREAD,
eol_char,
None,
separator,
quote_char,
)
.map(|(mean, std)| {
let n_rows = (bytes.len() as f32 / (mean - 0.01 * std)) as usize;
(n_rows / MIN_ROWS_PER_THREAD).clamp(1, max_threads)
})
.unwrap_or(1);
let file_chunks: Vec<(usize, usize)> =
get_file_chunks(bytes, n_threads, None, separator, quote_char, eol_char);
let iter = file_chunks.into_par_iter().map(|(start, stop)| {
let local_bytes = &bytes[start..stop];
let row_iterator = SplitLines::new(local_bytes, quote_char, eol_char);
if comment_prefix.is_some() {
Ok(row_iterator
.filter(|line| !line.is_empty() && !is_comment_line(line, comment_prefix))
.count())
} else {
Ok(row_iterator.count())
}
});
let count_result: PolarsResult<usize> = POOL.install(|| iter.sum());
match count_result {
Ok(val) => Ok(val - (has_header as usize)),
Err(err) => Err(err),
}
}
/// Skip the utf-8 Byte Order Mark.
/// credits to csv-core
pub(super) fn skip_bom(input: &[u8]) -> &[u8] {
if input.len() >= 3 && &input[0..3] == b"\xef\xbb\xbf" {
&input[3..]
} else {
input
}
}
/// Checks if a line in a CSV file is a comment based on the given comment prefix configuration.
///
/// This function is used during CSV parsing to determine whether a line should be ignored based on its starting characters.
pub(super) fn is_comment_line(line: &[u8], comment_prefix: Option<&CommentPrefix>) -> bool {
match comment_prefix {
Some(CommentPrefix::Single(c)) => line.starts_with(&[*c]),
Some(CommentPrefix::Multi(s)) => line.starts_with(s.as_bytes()),
None => false,
}
}
/// Find the nearest next line position.
/// Does not check for new line characters embedded in String fields.
pub(super) fn next_line_position_naive(input: &[u8], eol_char: u8) -> Option<usize> {
let pos = memchr::memchr(eol_char, input)? + 1;
if input.len() - pos == 0 {
return None;
}
Some(pos)
}
/// Find the nearest next line position that is not embedded in a String field.
pub(super) fn next_line_position(
mut input: &[u8],
mut expected_fields: Option<usize>,
separator: u8,
quote_char: Option<u8>,
eol_char: u8,
) -> Option<usize> {
fn accept_line(
line: &[u8],
expected_fields: usize,
separator: u8,
eol_char: u8,
quote_char: Option<u8>,
) -> bool {
let mut count = 0usize;
for (field, _) in SplitFields::new(line, separator, quote_char, eol_char) {
if memchr2_iter(separator, eol_char, field).count() >= expected_fields {
return false;
}
count += 1;
}
// if the latest field is missing
// e.g.:
// a,b,c
// vala,valb,
// SplitFields returns a count that is 1 less
// There fore we accept:
// expected == count
// and
// expected == count - 1
expected_fields.wrapping_sub(count) <= 1
}
// we check 3 subsequent lines for `accept_line` before we accept
// if 3 groups are rejected we reject completely
let mut rejected_line_groups = 0u8;
let mut total_pos = 0;
if input.is_empty() {
return None;
}
let mut lines_checked = 0u8;
loop {
if rejected_line_groups >= 3 {
return None;
}
lines_checked = lines_checked.wrapping_add(1);
// headers might have an extra value
// So if we have churned through enough lines
// we try one field less.
if lines_checked == u8::MAX {
if let Some(ef) = expected_fields {
expected_fields = Some(ef.saturating_sub(1))
}
};
let pos = memchr::memchr(eol_char, input)? + 1;
if input.len() - pos == 0 {
return None;
}
debug_assert!(pos <= input.len());
let new_input = unsafe { input.get_unchecked(pos..) };
let mut lines = SplitLines::new(new_input, quote_char, eol_char);
let line = lines.next();
match (line, expected_fields) {
// count the fields, and determine if they are equal to what we expect from the schema
(Some(line), Some(expected_fields)) => {
if accept_line(line, expected_fields, separator, eol_char, quote_char) {
let mut valid = true;
for line in lines.take(2) {
if !accept_line(line, expected_fields, separator, eol_char, quote_char) {
valid = false;
break;
}
}
if valid {
return Some(total_pos + pos);
} else {
rejected_line_groups += 1;
}
} else {
debug_assert!(pos < input.len());
unsafe {
input = input.get_unchecked(pos + 1..);
}
total_pos += pos + 1;
}
},
// don't count the fields
(Some(_), None) => return Some(total_pos + pos),
// // no new line found, check latest line (without eol) for number of fields
_ => return None,
}
}
}
pub(super) fn is_line_ending(b: u8, eol_char: u8) -> bool {
b == eol_char || b == b'\r'
}
pub(super) fn is_whitespace(b: u8) -> bool {
b == b' ' || b == b'\t'
}
#[inline]
fn skip_condition<F>(input: &[u8], f: F) -> &[u8]
where
F: Fn(u8) -> bool,
{
if input.is_empty() {
return input;
}
let read = input.iter().position(|b| !f(*b)).unwrap_or(input.len());
&input[read..]
}
/// Remove whitespace from the start of buffer.
/// Makes sure that the bytes stream starts with
/// 'field_1,field_2'
/// and not with
/// '\nfield_1,field_1'
#[inline]
pub(super) fn skip_whitespace(input: &[u8]) -> &[u8] {
skip_condition(input, is_whitespace)
}
#[inline]
pub(super) fn skip_line_ending(input: &[u8], eol_char: u8) -> &[u8] {
skip_condition(input, |b| is_line_ending(b, eol_char))
}
/// Get the mean and standard deviation of length of lines in bytes
pub(super) fn get_line_stats(
bytes: &[u8],
n_lines: usize,
eol_char: u8,
expected_fields: Option<usize>,
separator: u8,
quote_char: Option<u8>,
) -> Option<(f32, f32)> {
let mut lengths = Vec::with_capacity(n_lines);
let mut bytes_trunc;
let n_lines_per_iter = n_lines / 2;
let mut n_read = 0;
// sample from start and 75% in the file
for offset in [0, (bytes.len() as f32 * 0.75) as usize] {
bytes_trunc = &bytes[offset..];
let pos = next_line_position(
bytes_trunc,
expected_fields,
separator,
quote_char,
eol_char,
)?;
bytes_trunc = &bytes_trunc[pos + 1..];
for _ in offset..(offset + n_lines_per_iter) {
let pos = next_line_position_naive(bytes_trunc, eol_char)? + 1;
n_read += pos;
lengths.push(pos);
bytes_trunc = &bytes_trunc[pos..];
}
}
let n_samples = lengths.len();
let mean = (n_read as f32) / (n_samples as f32);
let mut std = 0.0;
for &len in lengths.iter() {
std += (len as f32 - mean).pow(2.0)
}
std = (std / n_samples as f32).sqrt();
Some((mean, std))
}
/// An adapted version of std::iter::Split.
/// This exists solely because we cannot split the file in lines naively as
///
/// ```text
/// for line in bytes.split(b'\n') {
/// ```
///
/// This will fail when strings fields are have embedded end line characters.
/// For instance: "This is a valid field\nI have multiples lines" is a valid string field, that contains multiple lines.
pub(super) struct SplitLines<'a> {
v: &'a [u8],
quote_char: u8,
eol_char: u8,
#[cfg(feature = "simd")]
simd_eol_char: SimdVec,
#[cfg(feature = "simd")]
simd_quote_char: SimdVec,
#[cfg(feature = "simd")]
previous_valid_eols: u64,
total_index: usize,
quoting: bool,
}
#[cfg(feature = "simd")]
const SIMD_SIZE: usize = 64;
#[cfg(feature = "simd")]
use std::simd::prelude::*;
#[cfg(feature = "simd")]
use polars_utils::clmul::prefix_xorsum_inclusive;
#[cfg(feature = "simd")]
type SimdVec = u8x64;
impl<'a> SplitLines<'a> {
pub(super) fn new(slice: &'a [u8], quote_char: Option<u8>, eol_char: u8) -> Self {
let quoting = quote_char.is_some();
let quote_char = quote_char.unwrap_or(b'\"');
#[cfg(feature = "simd")]
let simd_eol_char = SimdVec::splat(eol_char);
#[cfg(feature = "simd")]
let simd_quote_char = SimdVec::splat(quote_char);
Self {
v: slice,
quote_char,
eol_char,
#[cfg(feature = "simd")]
simd_eol_char,
#[cfg(feature = "simd")]
simd_quote_char,
#[cfg(feature = "simd")]
previous_valid_eols: 0,
total_index: 0,
quoting,
}
}
}
impl<'a> Iterator for SplitLines<'a> {
type Item = &'a [u8];
#[inline]
#[cfg(not(feature = "simd"))]
fn next(&mut self) -> Option<&'a [u8]> {
if self.v.is_empty() {
return None;
}
{
let mut pos = 0u32;
let mut iter = self.v.iter();
let mut in_field = false;
loop {
match iter.next() {
Some(&c) => {
pos += 1;
if self.quoting && c == self.quote_char {
// toggle between string field enclosure
// if we encounter a starting '"' -> in_field = true;
// if we encounter a closing '"' -> in_field = false;
in_field = !in_field;
}
// if we are not in a string and we encounter '\n' we can stop at this position.
else if c == self.eol_char && !in_field {
break;
}
},
None => {
let remainder = self.v;
self.v = &[];
return Some(remainder);
},
}
}
unsafe {
debug_assert!((pos as usize) <= self.v.len());
// return line up to this position
let ret = Some(
self.v
.get_unchecked(..(self.total_index + pos as usize - 1)),
);
// skip the '\n' token and update slice.
self.v = self.v.get_unchecked(self.total_index + pos as usize..);
ret
}
}
}
#[inline]
#[cfg(feature = "simd")]
fn next(&mut self) -> Option<&'a [u8]> {
// First check cached value
if self.previous_valid_eols != 0 {
let pos = self.previous_valid_eols.trailing_zeros() as usize;
self.previous_valid_eols >>= (pos + 1) as u64;
unsafe {
debug_assert!((pos) <= self.v.len());
// return line up to this position
let ret = Some(self.v.get_unchecked(..pos));
// skip the '\n' token and update slice.
self.v = self.v.get_unchecked(pos + 1..);
return ret;
}
}
if self.v.is_empty() {
return None;
}
self.total_index = 0;
let mut not_in_field_previous_iter = true;
loop {
let bytes = unsafe { self.v.get_unchecked(self.total_index..) };
if bytes.len() > SIMD_SIZE {
let lane: [u8; SIMD_SIZE] = unsafe {
bytes
.get_unchecked(0..SIMD_SIZE)
.try_into()
.unwrap_unchecked()
};
let simd_bytes = SimdVec::from(lane);
let eol_mask = simd_bytes.simd_eq(self.simd_eol_char).to_bitmask();
let valid_eols = if self.quoting {
let quote_mask = simd_bytes.simd_eq(self.simd_quote_char).to_bitmask();
let mut not_in_quote_field = prefix_xorsum_inclusive(quote_mask);
if not_in_field_previous_iter {
not_in_quote_field = !not_in_quote_field;
}
not_in_field_previous_iter = (not_in_quote_field & (1 << (SIMD_SIZE - 1))) > 0;
eol_mask & not_in_quote_field
} else {
eol_mask
};
if valid_eols != 0 {
let pos = valid_eols.trailing_zeros() as usize;
if pos == SIMD_SIZE - 1 {
self.previous_valid_eols = 0;
} else {
self.previous_valid_eols = valid_eols >> (pos + 1) as u64;
}
unsafe {
let pos = self.total_index + pos;
debug_assert!((pos) <= self.v.len());
// return line up to this position
let ret = Some(self.v.get_unchecked(..pos));
// skip the '\n' token and update slice.
self.v = self.v.get_unchecked(pos + 1..);
return ret;
}
} else {
self.total_index += SIMD_SIZE;
}
} else {
// Denotes if we are in a string field, started with a quote
let mut in_field = !not_in_field_previous_iter;
let mut pos = 0u32;
let mut iter = bytes.iter();
loop {
match iter.next() {
Some(&c) => {
pos += 1;
if self.quoting && c == self.quote_char {
// toggle between string field enclosure
// if we encounter a starting '"' -> in_field = true;
// if we encounter a closing '"' -> in_field = false;
in_field = !in_field;
}
// if we are not in a string and we encounter '\n' we can stop at this position.
else if c == self.eol_char && !in_field {
break;
}
},
None => {
let remainder = self.v;
self.v = &[];
return Some(remainder);
},
}
}
unsafe {
debug_assert!((pos as usize) <= self.v.len());
// return line up to this position
let ret = Some(
self.v
.get_unchecked(..(self.total_index + pos as usize - 1)),
);
// skip the '\n' token and update slice.
self.v = self.v.get_unchecked(self.total_index + pos as usize..);
return ret;
}
}
}
}
}
pub struct CountLines {
quote_char: u8,
eol_char: u8,
#[cfg(feature = "simd")]
simd_eol_char: SimdVec,
#[cfg(feature = "simd")]
simd_quote_char: SimdVec,
quoting: bool,
}
impl CountLines {
pub fn new(quote_char: Option<u8>, eol_char: u8) -> Self {
let quoting = quote_char.is_some();
let quote_char = quote_char.unwrap_or(b'\"');
#[cfg(feature = "simd")]
let simd_eol_char = SimdVec::splat(eol_char);
#[cfg(feature = "simd")]
let simd_quote_char = SimdVec::splat(quote_char);
Self {
quote_char,
eol_char,
#[cfg(feature = "simd")]
simd_eol_char,
#[cfg(feature = "simd")]
simd_quote_char,
quoting,
}
}
pub fn find_next(&self, bytes: &[u8], chunk_size: &mut usize) -> (usize, usize) {
loop {
let b = unsafe { bytes.get_unchecked(..(*chunk_size).min(bytes.len())) };
let (count, offset) = self.count(b);
if count > 0 || b.len() == bytes.len() {
return (count, offset);
}
*chunk_size *= 2;
}
}
// Returns count and offset in slice
#[cfg(feature = "simd")]
pub fn count(&self, bytes: &[u8]) -> (usize, usize) {
let mut total_idx = 0;
let original_bytes = bytes;
let mut count = 0;
let mut position = 0;
let mut not_in_field_previous_iter = true;
loop {
let bytes = unsafe { original_bytes.get_unchecked(total_idx..) };
if bytes.len() > SIMD_SIZE {
let lane: [u8; SIMD_SIZE] = unsafe {
bytes
.get_unchecked(0..SIMD_SIZE)
.try_into()
.unwrap_unchecked()
};
let simd_bytes = SimdVec::from(lane);
let eol_mask = simd_bytes.simd_eq(self.simd_eol_char).to_bitmask();
let valid_eols = if self.quoting {
let quote_mask = simd_bytes.simd_eq(self.simd_quote_char).to_bitmask();
let mut not_in_quote_field = prefix_xorsum_inclusive(quote_mask);
if not_in_field_previous_iter {
not_in_quote_field = !not_in_quote_field;
}
not_in_field_previous_iter = (not_in_quote_field & (1 << (SIMD_SIZE - 1))) > 0;
eol_mask & not_in_quote_field
} else {
eol_mask
};
if valid_eols != 0 {
count += valid_eols.count_ones() as usize;
position = total_idx + 63 - valid_eols.leading_zeros() as usize;
debug_assert_eq!(original_bytes[position], self.eol_char)
}
total_idx += SIMD_SIZE;
} else if bytes.is_empty() {
debug_assert!(count == 0 || original_bytes[position] == self.eol_char);
return (count, position);
} else {
let (c, o) = self.count_no_simd(bytes, !not_in_field_previous_iter);
let (count, position) = if c > 0 {
(count + c, total_idx + o)
} else {
(count, position)
};
debug_assert!(count == 0 || original_bytes[position] == self.eol_char);
return (count, position);
}
}
}
#[cfg(not(feature = "simd"))]
pub fn count(&self, bytes: &[u8]) -> (usize, usize) {
self.count_no_simd(bytes, false)
}
fn count_no_simd(&self, bytes: &[u8], in_field: bool) -> (usize, usize) {
let iter = bytes.iter();
let mut in_field = in_field;
let mut count = 0;
let mut position = 0;
for b in iter {
let c = *b;
if self.quoting && c == self.quote_char {
// toggle between string field enclosure
// if we encounter a starting '"' -> in_field = true;
// if we encounter a closing '"' -> in_field = false;
in_field = !in_field;
}
// If we are not in a string and we encounter '\n' we can stop at this position.
else if c == self.eol_char && !in_field {
position = (b as *const _ as usize) - (bytes.as_ptr() as usize);
count += 1;
}
}
debug_assert!(count == 0 || bytes[position] == self.eol_char);
(count, position)
}
}
#[inline]
fn find_quoted(bytes: &[u8], quote_char: u8, needle: u8) -> Option<usize> {
let mut in_field = false;
let mut idx = 0u32;
// micro optimizations
#[allow(clippy::explicit_counter_loop)]
for &c in bytes.iter() {
if c == quote_char {
// toggle between string field enclosure
// if we encounter a starting '"' -> in_field = true;
// if we encounter a closing '"' -> in_field = false;
in_field = !in_field;
}
if !in_field && c == needle {
return Some(idx as usize);
}
idx += 1;
}
None
}
#[inline]
pub(super) fn skip_this_line(bytes: &[u8], quote: Option<u8>, eol_char: u8) -> &[u8] {
let pos = match quote {
Some(quote) => find_quoted(bytes, quote, eol_char),
None => bytes.iter().position(|x| *x == eol_char),
};
match pos {
None => &[],
Some(pos) => &bytes[pos + 1..],
}
}
/// Parse CSV.
///
/// # Arguments
/// * `bytes` - input to parse
/// * `offset` - offset in bytes in total input. This is 0 if single threaded. If multi-threaded every
/// thread has a different offset.
/// * `projection` - Indices of the columns to project.
/// * `buffers` - Parsed output will be written to these buffers. Except for UTF8 data. The offsets of the
/// fields are written to the buffers. The UTF8 data will be parsed later.
#[allow(clippy::too_many_arguments)]
pub(super) fn parse_lines(
mut bytes: &[u8],
offset: usize,
separator: u8,
comment_prefix: Option<&CommentPrefix>,
quote_char: Option<u8>,
eol_char: u8,
missing_is_null: bool,
ignore_errors: bool,
mut truncate_ragged_lines: bool,
null_values: Option<&NullValuesCompiled>,
projection: &[usize],
buffers: &mut [Buffer],
n_lines: usize,
// length of original schema
schema_len: usize,
schema: &Schema,
) -> PolarsResult<usize> {
assert!(
!projection.is_empty(),
"at least one column should be projected"
);
// During projection pushdown we are not checking other csv fields.
// This would be very expensive and we don't care as we only want
// the projected columns.
if projection.len() != schema_len {
truncate_ragged_lines = true
}
// we use the pointers to track the no of bytes read.
let start = bytes.as_ptr() as usize;
let original_bytes_len = bytes.len();
let n_lines = n_lines as u32;
let mut line_count = 0u32;
loop {
if line_count > n_lines {
let end = bytes.as_ptr() as usize;
return Ok(end - start);
}
if bytes.is_empty() {
return Ok(original_bytes_len);
} else if is_comment_line(bytes, comment_prefix) {
// deal with comments
let bytes_rem = skip_this_line(bytes, quote_char, eol_char);
bytes = bytes_rem;
continue;
}
// Every line we only need to parse the columns that are projected.
// Therefore we check if the idx of the field is in our projected columns.
// If it is not, we skip the field.
let mut projection_iter = projection.iter().copied();
let mut next_projected = unsafe { projection_iter.next().unwrap_unchecked() };
let mut processed_fields = 0;
let mut iter = SplitFields::new(bytes, separator, quote_char, eol_char);
let mut idx = 0u32;
let mut read_sol = 0;
loop {
match iter.next() {
// end of line
None => {
bytes = unsafe { bytes.get_unchecked(std::cmp::min(read_sol, bytes.len())..) };
break;
},
Some((mut field, needs_escaping)) => {
let field_len = field.len();
// +1 is the split character that is consumed by the iterator.
read_sol += field_len + 1;
if idx == next_projected as u32 {
// the iterator is finished when it encounters a `\n`
// this could be preceded by a '\r'
unsafe {
if field_len > 0 && *field.get_unchecked(field_len - 1) == b'\r' {
field = field.get_unchecked(..field_len - 1);
}
}
debug_assert!(processed_fields < buffers.len());
let buf = unsafe {
// SAFETY: processed fields index can never exceed the projection indices.
buffers.get_unchecked_mut(processed_fields)
};
let mut add_null = false;
// if we have null values argument, check if this field equal null value
if let Some(null_values) = null_values {
let field = if needs_escaping && !field.is_empty() {
unsafe { field.get_unchecked(1..field.len() - 1) }
} else {
field
};
// SAFETY:
// process fields is in bounds
add_null = unsafe { null_values.is_null(field, idx as usize) }
}
if add_null {
buf.add_null(!missing_is_null && field.is_empty())
} else {
buf.add(field, ignore_errors, needs_escaping, missing_is_null)
.map_err(|e| {
let bytes_offset = offset + field.as_ptr() as usize - start;
let unparsable = String::from_utf8_lossy(field);
let column_name = schema.get_at_index(idx as usize).unwrap().0;
polars_err!(
ComputeError:
"could not parse `{}` as dtype `{}` at column '{}' (column number {})\n\n\
The current offset in the file is {} bytes.\n\
\n\
You might want to try:\n\
- increasing `infer_schema_length` (e.g. `infer_schema_length=10000`),\n\
- specifying correct dtype with the `schema_overrides` argument\n\
- setting `ignore_errors` to `True`,\n\
- adding `{}` to the `null_values` list.\n\n\
Original error: ```{}```",
&unparsable,
buf.dtype(),
column_name,
idx + 1,
bytes_offset,
&unparsable,
e
)
})?;
}
processed_fields += 1;
// if we have all projected columns we are done with this line
match projection_iter.next() {
Some(p) => next_projected = p,
None => {
if bytes.get(read_sol - 1) == Some(&eol_char) {
bytes = &bytes[read_sol..];
} else {
if !truncate_ragged_lines && read_sol < bytes.len() {
polars_bail!(ComputeError: r#"found more fields than defined in 'Schema'
Consider setting 'truncate_ragged_lines={}'."#, polars_error::constants::TRUE)
}
let bytes_rem = skip_this_line(
unsafe { bytes.get_unchecked(read_sol - 1..) },
quote_char,
eol_char,
);
bytes = bytes_rem;
}
break;
},
}
}
idx += 1;
},
}
}
// there can be lines that miss fields (also the comma values)
// this means the splitter won't process them.
// We traverse them to read them as null values.
while processed_fields < projection.len() {
debug_assert!(processed_fields < buffers.len());
let buf = unsafe {
// SAFETY: processed fields index can never exceed the projection indices.
buffers.get_unchecked_mut(processed_fields)
};
buf.add_null(!missing_is_null);
processed_fields += 1;
}
line_count += 1;
}
}
#[cfg(test)]
mod test {
use super::SplitLines;
#[test]
fn test_splitlines() {
let input = "1,\"foo\n\"\n2,\"foo\n\"\n";
let mut lines = SplitLines::new(input.as_bytes(), Some(b'"'), b'\n');
assert_eq!(lines.next(), Some("1,\"foo\n\"".as_bytes()));
assert_eq!(lines.next(), Some("2,\"foo\n\"".as_bytes()));
assert_eq!(lines.next(), None);
let input2 = "1,'foo\n'\n2,'foo\n'\n";
let mut lines2 = SplitLines::new(input2.as_bytes(), Some(b'\''), b'\n');
assert_eq!(lines2.next(), Some("1,'foo\n'".as_bytes()));
assert_eq!(lines2.next(), Some("2,'foo\n'".as_bytes()));
assert_eq!(lines2.next(), None);
}
}