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-rw-r--r--third_party/rust/litrs/src/byte/mod.rs107
-rw-r--r--third_party/rust/litrs/src/byte/tests.rs188
2 files changed, 295 insertions, 0 deletions
diff --git a/third_party/rust/litrs/src/byte/mod.rs b/third_party/rust/litrs/src/byte/mod.rs
new file mode 100644
index 0000000000..ffdff5d04a
--- /dev/null
+++ b/third_party/rust/litrs/src/byte/mod.rs
@@ -0,0 +1,107 @@
+use core::fmt;
+
+use crate::{
+ Buffer, ParseError,
+ err::{perr, ParseErrorKind::*},
+ escape::unescape,
+ parse::check_suffix,
+};
+
+
+/// A (single) byte literal, e.g. `b'k'` or `b'!'`.
+///
+/// See [the reference][ref] for more information.
+///
+/// [ref]: https://doc.rust-lang.org/reference/tokens.html#byte-literals
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub struct ByteLit<B: Buffer> {
+ raw: B,
+ /// Start index of the suffix or `raw.len()` if there is no suffix.
+ start_suffix: usize,
+ value: u8,
+}
+
+impl<B: Buffer> ByteLit<B> {
+ /// Parses the input as a byte literal. Returns an error if the input is
+ /// invalid or represents a different kind of literal.
+ pub fn parse(input: B) -> Result<Self, ParseError> {
+ if input.is_empty() {
+ return Err(perr(None, Empty));
+ }
+ if !input.starts_with("b'") {
+ return Err(perr(None, InvalidByteLiteralStart));
+ }
+
+ let (value, start_suffix) = parse_impl(&input)?;
+ Ok(Self { raw: input, value, start_suffix })
+ }
+
+ /// Returns the byte value that this literal represents.
+ pub fn value(&self) -> u8 {
+ self.value
+ }
+
+ /// The optional suffix. Returns `""` if the suffix is empty/does not exist.
+ pub fn suffix(&self) -> &str {
+ &(*self.raw)[self.start_suffix..]
+ }
+
+ /// Returns the raw input that was passed to `parse`.
+ pub fn raw_input(&self) -> &str {
+ &self.raw
+ }
+
+ /// Returns the raw input that was passed to `parse`, potentially owned.
+ pub fn into_raw_input(self) -> B {
+ self.raw
+ }
+
+}
+
+impl ByteLit<&str> {
+ /// Makes a copy of the underlying buffer and returns the owned version of
+ /// `Self`.
+ pub fn to_owned(&self) -> ByteLit<String> {
+ ByteLit {
+ raw: self.raw.to_owned(),
+ start_suffix: self.start_suffix,
+ value: self.value,
+ }
+ }
+}
+
+impl<B: Buffer> fmt::Display for ByteLit<B> {
+ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+ f.pad(&self.raw)
+ }
+}
+
+/// Precondition: must start with `b'`.
+#[inline(never)]
+pub(crate) fn parse_impl(input: &str) -> Result<(u8, usize), ParseError> {
+ let input_bytes = input.as_bytes();
+ let first = input_bytes.get(2).ok_or(perr(None, UnterminatedByteLiteral))?;
+ let (c, len) = match first {
+ b'\'' if input_bytes.get(3) == Some(&b'\'') => return Err(perr(2, UnescapedSingleQuote)),
+ b'\'' => return Err(perr(None, EmptyByteLiteral)),
+ b'\n' | b'\t' | b'\r' => return Err(perr(2, UnescapedSpecialWhitespace)),
+ b'\\' => unescape::<u8>(&input[2..], 2)?,
+ other if other.is_ascii() => (*other, 1),
+ _ => return Err(perr(2, NonAsciiInByteLiteral)),
+ };
+
+ match input[2 + len..].find('\'') {
+ Some(0) => {}
+ Some(_) => return Err(perr(None, OverlongByteLiteral)),
+ None => return Err(perr(None, UnterminatedByteLiteral)),
+ }
+
+ let start_suffix = 2 + len + 1;
+ let suffix = &input[start_suffix..];
+ check_suffix(suffix).map_err(|kind| perr(start_suffix, kind))?;
+
+ Ok((c, start_suffix))
+}
+
+#[cfg(test)]
+mod tests;
diff --git a/third_party/rust/litrs/src/byte/tests.rs b/third_party/rust/litrs/src/byte/tests.rs
new file mode 100644
index 0000000000..3cf16b5fc2
--- /dev/null
+++ b/third_party/rust/litrs/src/byte/tests.rs
@@ -0,0 +1,188 @@
+use crate::{ByteLit, Literal, test_util::{assert_parse_ok_eq, assert_roundtrip}};
+
+// ===== Utility functions =======================================================================
+
+macro_rules! check {
+ ($lit:literal) => { check!($lit, stringify!($lit), "") };
+ ($lit:literal, $input:expr, $suffix:literal) => {
+ let input = $input;
+ let expected = ByteLit {
+ raw: input,
+ start_suffix: input.len() - $suffix.len(),
+ value: $lit,
+ };
+
+ assert_parse_ok_eq(input, ByteLit::parse(input), expected.clone(), "ByteLit::parse");
+ assert_parse_ok_eq(input, Literal::parse(input), Literal::Byte(expected), "Literal::parse");
+ let lit = ByteLit::parse(input).unwrap();
+ assert_eq!(lit.value(), $lit);
+ assert_eq!(lit.suffix(), $suffix);
+ assert_roundtrip(expected.to_owned(), input);
+ };
+}
+
+
+// ===== Actual tests ============================================================================
+
+#[test]
+fn alphanumeric() {
+ check!(b'a');
+ check!(b'b');
+ check!(b'y');
+ check!(b'z');
+ check!(b'A');
+ check!(b'B');
+ check!(b'Y');
+ check!(b'Z');
+
+ check!(b'0');
+ check!(b'1');
+ check!(b'8');
+ check!(b'9');
+}
+
+#[test]
+fn special_chars() {
+ check!(b' ');
+ check!(b'!');
+ check!(b'"');
+ check!(b'#');
+ check!(b'$');
+ check!(b'%');
+ check!(b'&');
+ check!(b'(');
+ check!(b')');
+ check!(b'*');
+ check!(b'+');
+ check!(b',');
+ check!(b'-');
+ check!(b'.');
+ check!(b'/');
+ check!(b':');
+ check!(b';');
+ check!(b'<');
+ check!(b'=');
+ check!(b'>');
+ check!(b'?');
+ check!(b'@');
+ check!(b'[');
+ check!(b']');
+ check!(b'^');
+ check!(b'_');
+ check!(b'`');
+ check!(b'{');
+ check!(b'|');
+ check!(b'}');
+ check!(b'~');
+}
+
+#[test]
+fn quote_escapes() {
+ check!(b'\'');
+ check!(b'\"');
+}
+
+#[test]
+fn ascii_escapes() {
+ check!(b'\n');
+ check!(b'\r');
+ check!(b'\t');
+ check!(b'\\');
+ check!(b'\0');
+
+ check!(b'\x00');
+ check!(b'\x01');
+ check!(b'\x0c');
+ check!(b'\x0D');
+ check!(b'\x13');
+ check!(b'\x30');
+ check!(b'\x30');
+ check!(b'\x4B');
+ check!(b'\x6b');
+ check!(b'\x7F');
+ check!(b'\x7f');
+}
+
+#[test]
+fn byte_escapes() {
+ check!(b'\x80');
+ check!(b'\x8a');
+ check!(b'\x8C');
+ check!(b'\x99');
+ check!(b'\xa0');
+ check!(b'\xAd');
+ check!(b'\xfe');
+ check!(b'\xFe');
+ check!(b'\xfF');
+ check!(b'\xFF');
+}
+
+#[test]
+fn suffixes() {
+ check!(b'a', r##"b'a'peter"##, "peter");
+ check!(b'#', r##"b'#'peter"##, "peter");
+ check!(b'\n', r##"b'\n'peter"##, "peter");
+ check!(b'\'', r##"b'\''peter"##, "peter");
+ check!(b'\"', r##"b'\"'peter"##, "peter");
+ check!(b'\xFF', r##"b'\xFF'peter"##, "peter");
+}
+
+#[test]
+fn invald_escapes() {
+ assert_err!(ByteLit, r"b'\a'", UnknownEscape, 2..4);
+ assert_err!(ByteLit, r"b'\y'", UnknownEscape, 2..4);
+ assert_err!(ByteLit, r"b'\", UnterminatedEscape, 2..3);
+ assert_err!(ByteLit, r"b'\x'", UnterminatedEscape, 2..5);
+ assert_err!(ByteLit, r"b'\x1'", InvalidXEscape, 2..6);
+ assert_err!(ByteLit, r"b'\xaj'", InvalidXEscape, 2..6);
+ assert_err!(ByteLit, r"b'\xjb'", InvalidXEscape, 2..6);
+}
+
+#[test]
+fn unicode_escape_not_allowed() {
+ assert_err!(ByteLit, r"b'\u{0}'", UnicodeEscapeInByteLiteral, 2..4);
+ assert_err!(ByteLit, r"b'\u{00}'", UnicodeEscapeInByteLiteral, 2..4);
+ assert_err!(ByteLit, r"b'\u{b}'", UnicodeEscapeInByteLiteral, 2..4);
+ assert_err!(ByteLit, r"b'\u{B}'", UnicodeEscapeInByteLiteral, 2..4);
+ assert_err!(ByteLit, r"b'\u{7e}'", UnicodeEscapeInByteLiteral, 2..4);
+ assert_err!(ByteLit, r"b'\u{E4}'", UnicodeEscapeInByteLiteral, 2..4);
+ assert_err!(ByteLit, r"b'\u{e4}'", UnicodeEscapeInByteLiteral, 2..4);
+ assert_err!(ByteLit, r"b'\u{fc}'", UnicodeEscapeInByteLiteral, 2..4);
+ assert_err!(ByteLit, r"b'\u{Fc}'", UnicodeEscapeInByteLiteral, 2..4);
+ assert_err!(ByteLit, r"b'\u{fC}'", UnicodeEscapeInByteLiteral, 2..4);
+ assert_err!(ByteLit, r"b'\u{FC}'", UnicodeEscapeInByteLiteral, 2..4);
+ assert_err!(ByteLit, r"b'\u{b10}'", UnicodeEscapeInByteLiteral, 2..4);
+ assert_err!(ByteLit, r"b'\u{B10}'", UnicodeEscapeInByteLiteral, 2..4);
+ assert_err!(ByteLit, r"b'\u{0b10}'", UnicodeEscapeInByteLiteral, 2..4);
+ assert_err!(ByteLit, r"b'\u{2764}'", UnicodeEscapeInByteLiteral, 2..4);
+ assert_err!(ByteLit, r"b'\u{1f602}'", UnicodeEscapeInByteLiteral, 2..4);
+ assert_err!(ByteLit, r"b'\u{1F602}'", UnicodeEscapeInByteLiteral, 2..4);
+}
+
+#[test]
+fn parse_err() {
+ assert_err!(ByteLit, r"b''", EmptyByteLiteral, None);
+ assert_err!(ByteLit, r"b' ''", UnexpectedChar, 4..5);
+
+ assert_err!(ByteLit, r"b'", UnterminatedByteLiteral, None);
+ assert_err!(ByteLit, r"b'a", UnterminatedByteLiteral, None);
+ assert_err!(ByteLit, r"b'\n", UnterminatedByteLiteral, None);
+ assert_err!(ByteLit, r"b'\x35", UnterminatedByteLiteral, None);
+
+ assert_err!(ByteLit, r"b'ab'", OverlongByteLiteral, None);
+ assert_err!(ByteLit, r"b'a _'", OverlongByteLiteral, None);
+ assert_err!(ByteLit, r"b'\n3'", OverlongByteLiteral, None);
+
+ assert_err!(ByteLit, r"", Empty, None);
+
+ assert_err!(ByteLit, r"b'''", UnescapedSingleQuote, 2);
+ assert_err!(ByteLit, r"b''''", UnescapedSingleQuote, 2);
+
+ assert_err!(ByteLit, "b'\n'", UnescapedSpecialWhitespace, 2);
+ assert_err!(ByteLit, "b'\t'", UnescapedSpecialWhitespace, 2);
+ assert_err!(ByteLit, "b'\r'", UnescapedSpecialWhitespace, 2);
+
+ assert_err!(ByteLit, "b'న'", NonAsciiInByteLiteral, 2);
+ assert_err!(ByteLit, "b'犬'", NonAsciiInByteLiteral, 2);
+ assert_err!(ByteLit, "b'🦊'", NonAsciiInByteLiteral, 2);
+}
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