fn hex_digit(value: u32) -> char {
if value < 10 {
(b'0' + value as u8) as char
} else if value < 0x10 {
(b'a' + value as u8 - 10) as char
} else {
unreachable!()
}
}
pub fn quote_escape_str(s: &str) -> String {
let mut buf = String::new();
buf.push('"');
buf.extend(s.chars().flat_map(|c| c.escape_default()));
buf.push('"');
buf
}
pub fn quote_escape_bytes(bytes: &[u8]) -> String {
let mut buf = String::new();
buf.push('b');
buf.push('"');
for &b in bytes {
match b {
b'\n' => buf.push_str(r"\n"),
b'\r' => buf.push_str(r"\r"),
b'\t' => buf.push_str(r"\t"),
b'"' => buf.push_str("\\\""),
b'\\' => buf.push_str(r"\\"),
b'\x20'..=b'\x7e' => buf.push(b as char),
_ => {
buf.push_str(r"\x");
buf.push(hex_digit((b as u32) >> 4));
buf.push(hex_digit((b as u32) & 0x0f));
}
}
}
buf.push('"');
buf
}
#[cfg(test)]
mod test {
use super::*;
#[test]
fn test_quote_escape_bytes() {
assert_eq!("b\"\"", quote_escape_bytes(b""));
assert_eq!("b\"xyZW\"", quote_escape_bytes(b"xyZW"));
assert_eq!("b\"aa\\\"bb\"", quote_escape_bytes(b"aa\"bb"));
assert_eq!("b\"aa\\r\\n\\tbb\"", quote_escape_bytes(b"aa\r\n\tbb"));
assert_eq!(
"b\"\\x00\\x01\\x12\\xfe\\xff\"",
quote_escape_bytes(b"\x00\x01\x12\xfe\xff")
);
}
}