summaryrefslogtreecommitdiffstats
path: root/third_party/rust/line-wrap/src
diff options
context:
space:
mode:
authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-19 00:47:55 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-19 00:47:55 +0000
commit26a029d407be480d791972afb5975cf62c9360a6 (patch)
treef435a8308119effd964b339f76abb83a57c29483 /third_party/rust/line-wrap/src
parentInitial commit. (diff)
downloadfirefox-26a029d407be480d791972afb5975cf62c9360a6.tar.xz
firefox-26a029d407be480d791972afb5975cf62c9360a6.zip
Adding upstream version 124.0.1.upstream/124.0.1
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'third_party/rust/line-wrap/src')
-rw-r--r--third_party/rust/line-wrap/src/lib.rs351
-rw-r--r--third_party/rust/line-wrap/src/tests.rs281
2 files changed, 632 insertions, 0 deletions
diff --git a/third_party/rust/line-wrap/src/lib.rs b/third_party/rust/line-wrap/src/lib.rs
new file mode 100644
index 0000000000..3760d10175
--- /dev/null
+++ b/third_party/rust/line-wrap/src/lib.rs
@@ -0,0 +1,351 @@
+//! Efficiently insert line endings.
+//!
+//! If you have a buffer full of data and want to insert any sort of regularly-spaced separator,
+//! this will do it with a minimum of data copying. Commonly, this is to insert `\n` (see `lf()`) or `\r\n` (`crlf()`), but
+//! any byte sequence can be used.
+//!
+//! 1. Pick a line ending. For single byte separators, see `ByteLineEnding`, or for two bytes, `TwoByteLineEnding`. For
+//! arbitrary byte slices, use `SliceLineEnding`.
+//! 2. Call `line_wrap`.
+//! 3. Your data has been rearranged in place with the specified line ending inserted.
+//!
+//! # Examples
+//!
+//! ```
+//! use line_wrap::*;
+//! // suppose we have 80 bytes of data in a buffer and we want to wrap as per MIME.
+//! // Buffer is large enough to hold line endings.
+//! let mut data = vec![0; 82];
+//!
+//! assert_eq!(2, line_wrap(&mut data, 80, 76, &crlf()));
+//!
+//! // first line of zeroes
+//! let mut expected_data = vec![0; 76];
+//! // line ending
+//! expected_data.extend_from_slice(b"\r\n");
+//! // next line
+//! expected_data.extend_from_slice(&[0, 0, 0, 0]);
+//! assert_eq!(expected_data, data);
+//! ```
+//!
+//! # Performance
+//!
+//! On an i7 6850k:
+//!
+//! - 10 byte input, 1 byte line length takes ~60ns (~160MiB/s)
+//! - 100 byte input, 10 byte lines takes ~60ns (~1.6GiB/s)
+//! - Startup costs dominate at these small lengths
+//! - 1,000 byte input, 100 byte lines takes ~65ns (~15GiB/s)
+//! - 10,000 byte input, 100 byte lines takes ~550ns (~17GiB/s)
+//! - In general, `SliceLineEncoding` is about 75% the speed of the fixed-length impls.
+//!
+//! Naturally, try `cargo +nightly bench` on your hardware to get more representative data.
+extern crate safemem;
+
+/// Unix-style line ending.
+pub fn lf() -> ByteLineEnding { ByteLineEnding::new(b'\n') }
+
+/// Windows-style line ending.
+pub fn crlf() -> TwoByteLineEnding { TwoByteLineEnding::new(b'\r', b'\n') }
+
+/// Writes line endings.
+///
+/// The trait allows specialization for the common single and double byte cases, netting nice
+/// throughput improvements over simply using a slice for everything.
+pub trait LineEnding {
+ /// Write the line ending into the slice, which starts at the point where the ending should be written and is len() in length
+ fn write_ending(&self, slice: &mut [u8]);
+ /// The length of this particular line ending (must be constant and > 0)
+ fn len(&self) -> usize;
+}
+
+/// A single byte line ending.
+///
+/// See `lf()`.
+///
+/// # Examples
+///
+/// ```
+/// use line_wrap::*;
+///
+/// let ending = ByteLineEnding::new(b'\n');
+///
+/// let mut data = vec![1, 2, 3, 4, 5, 6, 255, 255];
+///
+/// assert_eq!(2, line_wrap(&mut data[..], 6, 2, &ending));
+///
+/// assert_eq!(vec![1, 2, b'\n', 3, 4, b'\n', 5, 6], data);
+/// ```
+pub struct ByteLineEnding {
+ byte: u8
+}
+
+impl ByteLineEnding {
+ pub fn new(byte: u8) -> ByteLineEnding {
+ ByteLineEnding {
+ byte
+ }
+ }
+}
+
+impl LineEnding for ByteLineEnding {
+ #[inline]
+ fn write_ending(&self, slice: &mut [u8]) {
+ slice[0] = self.byte;
+ }
+
+ #[inline]
+ fn len(&self) -> usize {
+ 1
+ }
+}
+
+/// A double byte line ending.
+///
+/// See `crlf()`.
+///
+/// # Examples
+///
+/// ```
+/// use line_wrap::*;
+///
+/// let ending = TwoByteLineEnding::new(b'\r', b'\n');
+///
+/// let mut data = vec![1, 2, 3, 4, 5, 6, 255, 255, 255, 255];
+///
+/// assert_eq!(4, line_wrap(&mut data[..], 6, 2, &ending));
+///
+/// assert_eq!(vec![1, 2, b'\r', b'\n', 3, 4, b'\r', b'\n', 5, 6], data);
+/// ```
+pub struct TwoByteLineEnding {
+ byte0: u8,
+ byte1: u8,
+}
+
+impl TwoByteLineEnding {
+ pub fn new(byte0: u8, byte1: u8) -> TwoByteLineEnding {
+ TwoByteLineEnding {
+ byte0,
+ byte1,
+ }
+ }
+}
+
+impl LineEnding for TwoByteLineEnding {
+ #[inline]
+ fn write_ending(&self, slice: &mut [u8]) {
+ slice[0] = self.byte0;
+ slice[1] = self.byte1;
+ }
+
+ #[inline]
+ fn len(&self) -> usize {
+ 2
+ }
+}
+
+/// A byte slice line ending.
+///
+/// Gives up some throughput compared to the specialized single/double byte impls, but works with
+/// any length.
+///
+/// # Examples
+///
+/// ```
+/// use line_wrap::*;
+///
+/// let ending = SliceLineEnding::new(b"xyz");
+///
+/// let mut data = vec![1, 2, 3, 4, 5, 6, 255, 255, 255, 255, 255, 255];
+///
+/// assert_eq!(6, line_wrap(&mut data[..], 6, 2, &ending));
+///
+/// assert_eq!(vec![1, 2, b'x', b'y', b'z', 3, 4, b'x', b'y', b'z', 5, 6], data);
+/// ```
+pub struct SliceLineEnding<'a> {
+ slice: &'a [u8]
+}
+
+impl<'a> SliceLineEnding<'a> {
+ pub fn new(slice: &[u8]) -> SliceLineEnding {
+ SliceLineEnding {
+ slice
+ }
+ }
+}
+
+impl<'a> LineEnding for SliceLineEnding<'a> {
+ #[inline]
+ fn write_ending(&self, slice: &mut [u8]) {
+ slice.copy_from_slice(self.slice);
+ }
+
+ #[inline]
+ fn len(&self) -> usize {
+ self.slice.len()
+ }
+}
+
+/// Insert line endings into the input.
+///
+/// Endings are inserted after each complete line, except the last line, even if the last line takes
+/// up the full line width.
+///
+/// - `buf` must be large enough to handle the increased size after endings are inserted. In other
+/// words, `buf.len() >= input_len / line_len * line_ending.len()`.
+/// - `input_len` is the length of the unwrapped in `buf`.
+/// - `line_len` is the desired line width without line ending characters.
+///
+/// Returns the number of line ending bytes added.
+///
+/// # Panics
+///
+/// - When `line_ending.len() == 0`
+/// - When `buf` is too small to contain the original input and its new line endings
+pub fn line_wrap<L: LineEnding>(
+ buf: &mut [u8],
+ input_len: usize,
+ line_len: usize,
+ line_ending: &L,
+) -> usize {
+ assert!(line_ending.len() > 0);
+
+ if input_len <= line_len {
+ return 0;
+ }
+
+ let line_ending_len = line_ending.len();
+ let line_wrap_params = line_wrap_parameters(input_len, line_len, line_ending_len);
+
+ // ptr.offset() is undefined if it wraps, and there is no checked_offset(). However, because
+ // we perform this check up front to make sure we have enough capacity, we know that none of
+ // the subsequent pointer operations (assuming they implement the desired behavior of course!)
+ // will overflow.
+ assert!(
+ buf.len() >= line_wrap_params.total_len,
+ "Buffer must be able to hold encoded data after line wrapping"
+ );
+
+ // Move the last line, either partial or full, by itself as it does not have a line ending
+ // afterwards
+ let last_line_start = input_len.checked_sub(line_wrap_params.last_line_len)
+ .expect("Last line start index underflow");
+ // last line starts immediately after all the wrapped full lines
+ let new_line_start = line_wrap_params.total_full_wrapped_lines_len;
+
+ safemem::copy_over(
+ buf,
+ last_line_start,
+ new_line_start,
+ line_wrap_params.last_line_len,
+ );
+
+ let mut total_line_ending_bytes = 0;
+
+ // initialize so that the initial decrement will set them correctly
+ let mut old_line_start = last_line_start;
+ let mut new_line_start = line_wrap_params.total_full_wrapped_lines_len;
+
+ // handle the full lines
+ for _ in 0..line_wrap_params.lines_with_endings {
+ // the index after the end of the line ending we're about to write is the start of the next
+ // line
+ let end_of_line_ending = new_line_start;
+ let start_of_line_ending = end_of_line_ending
+ .checked_sub(line_ending_len)
+ .expect("Line ending start index underflow");
+
+ // doesn't underflow because it's decremented `line_wrap_params.lines_with_endings` times
+ old_line_start = old_line_start.checked_sub(line_len)
+ .expect("Old line start index underflow");
+ new_line_start = new_line_start.checked_sub(line_wrap_params.line_with_ending_len)
+ .expect("New line start index underflow");
+
+ safemem::copy_over(buf, old_line_start, new_line_start, line_len);
+
+ line_ending.write_ending(&mut buf[start_of_line_ending..(end_of_line_ending)]);
+ total_line_ending_bytes += line_ending_len;
+ }
+
+ assert_eq!(line_wrap_params.total_line_endings_len, total_line_ending_bytes);
+
+ total_line_ending_bytes
+}
+
+#[derive(Debug, PartialEq)]
+struct LineWrapParameters {
+ line_with_ending_len: usize,
+ // number of lines that need an ending
+ lines_with_endings: usize,
+ // length of last line (which never needs an ending)
+ last_line_len: usize,
+ // length of lines that need an ending (which are always full lines), with their endings
+ total_full_wrapped_lines_len: usize,
+ // length of all lines, including endings for the ones that need them
+ total_len: usize,
+ // length of the line endings only
+ total_line_endings_len: usize,
+}
+
+/// Calculations about how many lines we'll get for a given line length, line ending, etc.
+/// This assumes that the last line will not get an ending, even if it is the full line length.
+// Inlining improves short input single-byte by 25%.
+#[inline]
+fn line_wrap_parameters(
+ input_len: usize,
+ line_len: usize,
+ line_ending_len: usize,
+) -> LineWrapParameters {
+ let line_with_ending_len = line_len
+ .checked_add(line_ending_len)
+ .expect("Line length with ending exceeds usize");
+
+ if input_len <= line_len {
+ // no wrapping needed
+ return LineWrapParameters {
+ line_with_ending_len,
+ lines_with_endings: 0,
+ last_line_len: input_len,
+ total_full_wrapped_lines_len: 0,
+ total_len: input_len,
+ total_line_endings_len: 0,
+ };
+ };
+
+ // lines_with_endings > 0, last_line_len > 0
+ let (lines_with_endings, last_line_len) = if input_len % line_len > 0 {
+ // Every full line has an ending since there is a partial line at the end
+ (input_len / line_len, input_len % line_len)
+ } else {
+ // Every line is a full line, but no trailing ending.
+ // Subtraction will not underflow since we know input_len > line_len.
+ (input_len / line_len - 1, line_len)
+ };
+
+ // Should we expose exceeding usize via Result to be kind to 16-bit users? Or is that
+ // always going to be a panic anyway in practice?
+
+ // length of just the full lines with line endings
+ let total_full_wrapped_lines_len = lines_with_endings
+ .checked_mul(line_with_ending_len)
+ .expect("Full lines with endings length exceeds usize");
+ // all lines with appropriate endings, including the last line
+ let total_len = total_full_wrapped_lines_len
+ .checked_add(last_line_len)
+ .expect("All lines with endings length exceeds usize");
+ let total_line_endings_len = lines_with_endings
+ .checked_mul(line_ending_len)
+ .expect("Total line endings length exceeds usize");
+
+ LineWrapParameters {
+ line_with_ending_len,
+ lines_with_endings,
+ last_line_len,
+ total_full_wrapped_lines_len,
+ total_len,
+ total_line_endings_len,
+ }
+}
+
+#[cfg(test)]
+mod tests; \ No newline at end of file
diff --git a/third_party/rust/line-wrap/src/tests.rs b/third_party/rust/line-wrap/src/tests.rs
new file mode 100644
index 0000000000..6793e10968
--- /dev/null
+++ b/third_party/rust/line-wrap/src/tests.rs
@@ -0,0 +1,281 @@
+extern crate rand;
+
+
+use super::*;
+use self::rand::distributions::{Distribution, Range};
+use self::rand::{Rng, FromEntropy};
+
+#[test]
+fn line_params_perfect_multiple_of_line_length_lf() {
+ let params = line_wrap_parameters(100, 20, lf().len());
+
+ assert_eq!(
+ LineWrapParameters {
+ line_with_ending_len: 21,
+ lines_with_endings: 4,
+ last_line_len: 20,
+ total_full_wrapped_lines_len: 84,
+ total_len: 104,
+ total_line_endings_len: 4,
+ },
+ params
+ );
+}
+
+#[test]
+fn line_params_partial_last_line_crlf() {
+ let params = line_wrap_parameters(103, 20, crlf().len());
+
+ assert_eq!(
+ LineWrapParameters {
+ line_with_ending_len: 22,
+ lines_with_endings: 5,
+ last_line_len: 3,
+ total_full_wrapped_lines_len: 110,
+ total_len: 113,
+ total_line_endings_len: 10,
+ },
+ params
+ );
+}
+
+#[test]
+fn line_params_line_len_1_crlf() {
+ let params = line_wrap_parameters(100, 1, crlf().len());
+
+ assert_eq!(
+ LineWrapParameters {
+ line_with_ending_len: 3,
+ lines_with_endings: 99,
+ last_line_len: 1,
+ total_full_wrapped_lines_len: 99 * 3,
+ total_len: 99 * 3 + 1,
+ total_line_endings_len: 99 * 2,
+ },
+ params
+ );
+}
+
+#[test]
+fn line_params_line_len_longer_than_input_crlf() {
+ let params = line_wrap_parameters(100, 200, crlf().len());
+
+ assert_eq!(
+ LineWrapParameters {
+ line_with_ending_len: 202,
+ lines_with_endings: 0,
+ last_line_len: 100,
+ total_full_wrapped_lines_len: 0,
+ total_len: 100,
+ total_line_endings_len: 0,
+ },
+ params
+ );
+}
+
+#[test]
+fn line_params_line_len_same_as_input_crlf() {
+ let params = line_wrap_parameters(100, 100, crlf().len());
+
+ assert_eq!(
+ LineWrapParameters {
+ line_with_ending_len: 102,
+ lines_with_endings: 0,
+ last_line_len: 100,
+ total_full_wrapped_lines_len: 0,
+ total_len: 100,
+ total_line_endings_len: 0,
+ },
+ params
+ );
+}
+
+
+#[test]
+fn line_wrap_length_1_lf() {
+ let mut buf = vec![0x1, 0x2, 0x3, 0x4];
+
+ assert_eq!(3, do_line_wrap(&mut buf, 1, &lf()));
+
+ assert_eq!(vec![0x1, 0xA, 0x2, 0xA, 0x3, 0xA, 0x4], buf);
+}
+
+#[test]
+fn line_wrap_length_1_crlf() {
+ let mut buf = vec![0x1, 0x2, 0x3, 0x4];
+
+ assert_eq!(6, do_line_wrap(&mut buf, 1, &crlf()));
+
+ assert_eq!(vec![0x1, 0xD, 0xA, 0x2, 0xD, 0xA, 0x3, 0xD, 0xA, 0x4], buf);
+}
+
+#[test]
+fn line_wrap_length_2_lf_full_lines() {
+ let mut buf = vec![0x1, 0x2, 0x3, 0x4];
+
+ assert_eq!(1, do_line_wrap(&mut buf, 2, &lf()));
+
+ assert_eq!(vec![0x1, 0x2, 0xA, 0x3, 0x4], buf);
+}
+
+#[test]
+fn line_wrap_length_2_crlf_full_lines() {
+ let mut buf = vec![0x1, 0x2, 0x3, 0x4];
+
+ assert_eq!(2, do_line_wrap(&mut buf, 2, &crlf()));
+
+ assert_eq!(vec![0x1, 0x2, 0xD, 0xA, 0x3, 0x4], buf);
+}
+
+#[test]
+fn line_wrap_length_2_lf_partial_line() {
+ let mut buf = vec![0x1, 0x2, 0x3, 0x4, 0x5];
+
+ assert_eq!(2, do_line_wrap(&mut buf, 2, &lf()));
+
+ assert_eq!(vec![0x1, 0x2, 0xA, 0x3, 0x4, 0xA, 0x5], buf);
+}
+
+#[test]
+fn line_wrap_length_2_crlf_partial_line() {
+ let mut buf = vec![0x1, 0x2, 0x3, 0x4, 0x5];
+
+ assert_eq!(4, do_line_wrap(&mut buf, 2, &crlf()));
+
+ assert_eq!(vec![0x1, 0x2, 0xD, 0xA, 0x3, 0x4, 0xD, 0xA, 0x5], buf);
+}
+
+#[test]
+fn line_wrap_random_slice() {
+ let mut buf: Vec<u8> = Vec::new();
+ let buf_range = Range::new(10, 1000);
+ let line_range = Range::new(10, 100);
+ let mut rng = rand::rngs::SmallRng::from_entropy();
+ let mut line_ending_bytes: Vec<u8> = Vec::new();
+
+ for _ in 0..10_000 {
+ buf.clear();
+ line_ending_bytes.clear();
+
+ let buf_len = buf_range.sample(&mut rng);
+ let line_len = line_range.sample(&mut rng);
+
+ for _ in 0..buf_len {
+ buf.push(rng.gen());
+ }
+
+ line_ending_bytes.clear();
+ for _ in 0..rng.gen_range(1, 11) {
+ line_ending_bytes.push(rng.gen());
+ }
+ let line_ending = SliceLineEnding::new(&line_ending_bytes);
+
+ let _ = do_line_wrap(&mut buf, line_len, &line_ending);
+ }
+}
+
+#[test]
+fn line_wrap_random_single_byte() {
+ let mut buf: Vec<u8> = Vec::new();
+ let buf_range = Range::new(10, 1000);
+ let line_range = Range::new(10, 100);
+ let mut rng = rand::rngs::SmallRng::from_entropy();
+
+ for _ in 0..10_000 {
+ buf.clear();
+
+ let buf_len = buf_range.sample(&mut rng);
+ let line_len = line_range.sample(&mut rng);
+
+ for _ in 0..buf_len {
+ buf.push(rng.gen());
+ }
+
+ let line_ending = ByteLineEnding::new(rng.gen());
+
+ let _ = do_line_wrap(&mut buf, line_len, &line_ending);
+ }
+}
+
+#[test]
+fn line_wrap_random_two_bytes() {
+ let mut buf: Vec<u8> = Vec::new();
+ let buf_range = Range::new(10, 1000);
+ let line_range = Range::new(10, 100);
+ let mut rng = rand::rngs::SmallRng::from_entropy();
+
+ for _ in 0..10_000 {
+ buf.clear();
+
+ let buf_len = buf_range.sample(&mut rng);
+ let line_len = line_range.sample(&mut rng);
+
+ for _ in 0..buf_len {
+ buf.push(rng.gen());
+ }
+
+ let line_ending = TwoByteLineEnding::new(rng.gen(), rng.gen());
+
+ let _ = do_line_wrap(&mut buf, line_len, &line_ending);
+ }
+}
+
+fn do_line_wrap<L: LineEnding>(buf: &mut Vec<u8>, line_len: usize, line_ending: &L) -> usize {
+ let mut rng = rand::rngs::SmallRng::from_entropy();
+
+ let orig_len = buf.len();
+ let orig_buf = buf.to_vec();
+
+ // Add on extra bytes so we'll have sentinel bytes at the end that shouldn't get changed.
+ for _ in 0..(1000 + line_ending.len() * orig_len) {
+ buf.push(rng.gen());
+ }
+
+ let before_line_wrap = buf.to_vec();
+
+ let params = line_wrap_parameters(orig_len, line_len, line_ending.len());
+
+ let bytes_written = line_wrap::<L>(&mut buf[..], orig_len, line_len, line_ending);
+
+ assert_eq!(params.total_line_endings_len, bytes_written);
+ assert_eq!(params.lines_with_endings * line_ending.len(), bytes_written);
+ assert_eq!(params.total_len, orig_len + bytes_written);
+
+ // make sure line_wrap didn't touch anything beyond what it should
+ assert_eq!(before_line_wrap[params.total_len..], buf[params.total_len..]);
+
+ {
+ // also make sure that line wrapping will fit into a slice no bigger than what it should
+ // need
+ let mut buf_strict = before_line_wrap.to_vec();
+ buf_strict.truncate(orig_len);
+ // fill in some fresh random garbage
+ while buf_strict.len() < params.total_len {
+ buf_strict.push(rng.gen());
+ }
+ let bytes_written_precise_fit = line_wrap::<L>(
+ &mut buf_strict,
+ orig_len,
+ line_len,
+ line_ending,
+ );
+ assert_eq!(params.total_len, buf_strict.len());
+ assert_eq!(bytes_written, bytes_written_precise_fit);
+ assert_eq!(&buf[0..(params.total_len)], &buf_strict[..]);
+
+ // since we have a copy of the wrapped bytes lying around, remove the endings and see
+ // if we get the original
+ for line_ending_num in 0..params.lines_with_endings {
+ let line_ending_offset = (line_ending_num + 1) * line_len;
+
+ for _ in 0..line_ending.len() {
+ let _ = buf_strict.remove(line_ending_offset);
+ }
+ }
+ assert_eq!(orig_buf, buf_strict);
+ }
+
+ buf.truncate(params.total_len);
+
+ bytes_written
+} \ No newline at end of file