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use std::{fmt, ops::Range};
use crate::{Buffer, Error, ErrorKind, escape::unescape};
#[derive(Debug, Clone, PartialEq, Eq)]
pub struct ByteStringLit<B: Buffer> {
raw: B,
value: Option<Vec<u8>>,
num_hashes: Option<u32>,
}
impl<B: Buffer> ByteStringLit<B> {
pub fn parse(input: B) -> Result<Self, Error> {
if input.is_empty() {
return Err(Error::spanless(ErrorKind::Empty));
}
if !input.starts_with(r#"b""#) && !input.starts_with("br") {
return Err(Error::spanless(ErrorKind::InvalidByteStringLiteralStart));
}
Self::parse_impl(input)
}
pub fn value(&self) -> &[u8] {
self.value.as_deref().unwrap_or(&self.raw.as_bytes()[self.inner_range()])
}
pub fn into_value(self) -> B::ByteCow {
let inner_range = self.inner_range();
let Self { raw, value, .. } = self;
value.map(B::ByteCow::from).unwrap_or_else(|| raw.cut(inner_range).into_byte_cow())
}
pub fn is_raw_byte_string(&self) -> bool {
self.num_hashes.is_some()
}
fn inner_range(&self) -> Range<usize> {
match self.num_hashes {
None => 2..self.raw.len() - 1,
Some(n) => 2 + n as usize + 1..self.raw.len() - n as usize - 1,
}
}
pub(crate) fn parse_impl(input: B) -> Result<Self, Error> {
if input.starts_with(r"br") {
let num_hashes = input[2..].bytes().position(|b| b != b'#')
.ok_or(Error::spanless(ErrorKind::InvalidLiteral))?;
if input.as_bytes().get(2 + num_hashes) != Some(&b'"') {
return Err(Error::spanless(ErrorKind::InvalidLiteral));
}
let start_inner = 2 + num_hashes + 1;
let hashes = &input[2..num_hashes + 2];
let mut closing_quote_pos = None;
for (i, b) in input[start_inner..].bytes().enumerate() {
if b == b'"' && input[start_inner + i + 1..].starts_with(hashes) {
closing_quote_pos = Some(i + start_inner);
break;
}
if !b.is_ascii() {
return Err(Error::single(i + start_inner, ErrorKind::NonAsciiInByteLiteral));
}
}
let closing_quote_pos = closing_quote_pos
.ok_or(Error::spanless(ErrorKind::UnterminatedRawString))?;
if closing_quote_pos + num_hashes != input.len() - 1 {
return Err(Error::new(
closing_quote_pos + num_hashes + 1..input.len(),
ErrorKind::UnexpectedChar,
));
}
Ok(Self {
raw: input,
value: None,
num_hashes: Some(num_hashes as u32),
})
} else {
let mut i = 2;
let mut end_last_escape = 2;
let mut value = Vec::new();
while i < input.len() - 1 {
match input.as_bytes()[i] {
b'\\' => {
let (b, len) = unescape::<u8>(&input[i..input.len() - 1], i)?;
value.extend_from_slice(&input.as_bytes()[end_last_escape..i]);
value.push(b);
i += len;
end_last_escape = i;
}
b'\r' if input.as_bytes()[i + 1] != b'\n'
=> return Err(Error::single(i, ErrorKind::IsolatedCr)),
b'"' => return Err(Error::new(i + 1..input.len(), ErrorKind::UnexpectedChar)),
b if !b.is_ascii()
=> return Err(Error::single(i, ErrorKind::NonAsciiInByteLiteral)),
_ => i += 1,
}
}
if input.as_bytes()[input.len() - 1] != b'"' || input.len() == 2 {
return Err(Error::spanless(ErrorKind::UnterminatedString));
}
let value = if value.is_empty() {
None
} else {
value.extend_from_slice(&input.as_bytes()[end_last_escape..input.len() - 1]);
Some(value)
};
Ok(Self {
raw: input,
value,
num_hashes: None,
})
}
}
}
impl ByteStringLit<&str> {
pub fn into_owned(self) -> ByteStringLit<String> {
ByteStringLit {
raw: self.raw.to_owned(),
value: self.value,
num_hashes: self.num_hashes,
}
}
}
impl<B: Buffer> fmt::Display for ByteStringLit<B> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.pad(&self.raw)
}
}
#[cfg(test)]
mod tests;