git.delta.rocks / jrsonnet / refs/commits / c1e14347eca8

1use std::str::Chars;
2
3fn decode_unicode(chars: &mut Chars) -> Option<u16> {
4	IntoIterator::into_iter([chars.next()?, chars.next()?, chars.next()?, chars.next()?])
5		.map(|c| c.to_digit(16).map(|f| f as u16))
6		.try_fold(0u16, |acc, v| Some((acc << 4) | (v?)))
7}
8
1pub fn unescape(s: &str) -> Option<String> {9pub fn unescape(s: &str) -> Option<String> {
2	let mut chars = s.chars();10	let mut chars = s.chars();
14			'n' => out.push('\n'),22			'n' => out.push('\n'),
15			'r' => out.push('\r'),23			'r' => out.push('\r'),
16			't' => out.push('\t'),24			't' => out.push('\t'),
17			'u' => {25			'u' => match decode_unicode(&mut chars)? {
18				let c = IntoIterator::into_iter([26				// May only be second byte
19					chars.next()?,27				0xDC00..=0xDFFF => return None,
28				// Surrogate pair
29				n1 @ 0xD800..=0xDBFF => {
30					if chars.next() != Some('\\') {
31						return None;
32					}
20					chars.next()?,33					if chars.next() != Some('u') {
21					chars.next()?,34						return None;
35					}
22					chars.next()?,36					let n2 = decode_unicode(&mut chars)?;
23				])
24				.map(|c| c.to_digit(16))37					if !matches!(n2, 0xDC00..=0xDFFF) {
38						return None;
39					}
25				.try_fold(0u32, |acc, v| Some((acc << 8) | (v?)))?;40					let n = (((n1 - 0xD800) as u32) << 10 | (n2 - 0xDC00) as u32) + 0x1_0000;
41					out.push(char::from_u32(n)?);
42				}
26				out.push(char::from_u32(c)?)43				n => out.push(char::from_u32(n as u32)?),
27			}44			},
28			'x' => {45			'x' => {
29				let c = IntoIterator::into_iter([chars.next()?, chars.next()?])46				let c = IntoIterator::into_iter([chars.next()?, chars.next()?])
30					.map(|c| c.to_digit(16))47					.map(|c| c.to_digit(16))