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use std::fmt;
use std::error;
#[derive(Debug)]
#[derive(PartialEq)]
pub enum ParseMode {
Strict,
Robust,
}
#[derive(Debug)]
pub enum QuotedPrintableError {
InvalidByte,
LineTooLong,
IncompleteHexOctet,
InvalidHexOctet,
LowercaseHexOctet,
}
impl fmt::Display for QuotedPrintableError {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
match *self {
QuotedPrintableError::InvalidByte => {
write!(f,
"A unallowed byte was found in the quoted-printable input")
}
QuotedPrintableError::LineTooLong => {
write!(f,
"A line length in the quoted-printed input exceeded 76 bytes")
}
QuotedPrintableError::IncompleteHexOctet => {
write!(f,
"A '=' followed by only one character was found in the input")
}
QuotedPrintableError::InvalidHexOctet => {
write!(f,
"A '=' followed by non-hex characters was found in the input")
}
QuotedPrintableError::LowercaseHexOctet => {
write!(f, "A '=' was followed by lowercase hex characters")
}
}
}
}
impl error::Error for QuotedPrintableError {
fn description(&self) -> &str {
"invalid quoted-printable input"
}
fn cause(&self) -> Option<&error::Error> {
None
}
}
pub fn decode_str(input: &str, mode: ParseMode) -> Result<Vec<u8>, QuotedPrintableError> {
decode(input.as_bytes(), mode)
}
pub fn decode(input: &[u8], mode: ParseMode) -> Result<Vec<u8>, QuotedPrintableError> {
let filtered = input.into_iter()
.filter_map(|&c| match c {
b'\t' | b'\r' | b'\n' | b' '...b'~' => Some(c as char),
_ => None,
})
.collect::<String>();
if mode == ParseMode::Strict && filtered.len() != input.len() {
return Err(QuotedPrintableError::InvalidByte);
}
let mut decoded = Vec::new();
let mut lines = filtered.lines();
let mut add_line_break = None;
loop {
let mut bytes = match lines.next() {
Some(v) => v.trim_right().bytes(),
None => {
if mode == ParseMode::Strict && add_line_break == Some(false) {
return Err(QuotedPrintableError::IncompleteHexOctet);
}
break;
}
};
if mode == ParseMode::Strict && bytes.len() > 76 {
return Err(QuotedPrintableError::LineTooLong);
}
if add_line_break == Some(true) {
decoded.push(b'\r');
decoded.push(b'\n');
add_line_break = Some(false);
}
loop {
let byte = match bytes.next() {
Some(v) => v,
None => {
add_line_break = Some(true);
break;
}
};
if byte == b'=' {
let upper = match bytes.next() {
Some(v) => v,
None => break,
};
let lower = match bytes.next() {
Some(v) => v,
None => {
if mode == ParseMode::Strict {
return Err(QuotedPrintableError::IncompleteHexOctet);
}
decoded.push(byte);
decoded.push(upper);
add_line_break = Some(true);
break;
}
};
let upper_char = upper as char;
let lower_char = lower as char;
if upper_char.is_digit(16) && lower_char.is_digit(16) {
if mode == ParseMode::Strict {
if upper_char.to_uppercase().next() != Some(upper_char) ||
lower_char.to_uppercase().next() != Some(lower_char) {
return Err(QuotedPrintableError::LowercaseHexOctet);
}
}
let combined = upper_char.to_digit(16).unwrap() << 4 |
lower_char.to_digit(16).unwrap();
decoded.push(combined as u8);
} else {
if mode == ParseMode::Strict {
return Err(QuotedPrintableError::InvalidHexOctet);
}
decoded.push(byte);
decoded.push(upper);
decoded.push(lower);
}
} else {
decoded.push(byte);
}
}
}
Ok(decoded)
}
fn append(result: &mut Vec<u8>, to_append: &[u8], bytes_on_line: &mut usize, backup_pos: &mut usize) {
if *bytes_on_line + to_append.len() > 76 {
if *bytes_on_line == 76 {
*bytes_on_line = result.len() - *backup_pos;
result.insert(*backup_pos, b'=');
result.insert(*backup_pos + 1, b'\r');
result.insert(*backup_pos + 2, b'\n');
} else {
result.extend([b'=', b'\r', b'\n'].iter().cloned());
*bytes_on_line = 0;
}
}
result.extend(to_append);
*bytes_on_line = *bytes_on_line + to_append.len();
*backup_pos = result.len() - to_append.len();
}
pub fn encode(input: &[u8]) -> Vec<u8> {
let mut result = Vec::new();
let mut on_line: usize = 0;
let mut backup_pos: usize = 0;
let mut it = input.iter();
loop {
match it.next() {
Some(v @ &b'=') => {
append(&mut result, format!("={:02X}", *v).as_bytes(), &mut on_line, &mut backup_pos);
}
Some(v @ &b'\t') |
Some(v @ &b' '...b'~') => {
append(&mut result, &[*v], &mut on_line, &mut backup_pos);
}
Some(&b'\r') => {
match it.next() {
Some(&b'\n') => {
result.push(b'\r');
result.push(b'\n');
on_line = 0;
}
Some(v @ &b'=') => {
append(&mut result, "=0D".as_bytes(), &mut on_line, &mut backup_pos);
append(&mut result, format!("={:02X}", *v).as_bytes(), &mut on_line, &mut backup_pos);
}
Some(v @ &b'\t') |
Some(v @ &b' '...b'~') => {
append(&mut result, "=0D".as_bytes(), &mut on_line, &mut backup_pos);
append(&mut result, &[*v], &mut on_line, &mut backup_pos);
}
Some(v) => {
append(&mut result, "=0D".as_bytes(), &mut on_line, &mut backup_pos);
append(&mut result, format!("={:02X}", *v).as_bytes(), &mut on_line, &mut backup_pos);
}
None => {
append(&mut result, "=0D".as_bytes(), &mut on_line, &mut backup_pos);
}
};
}
Some(v) => {
append(&mut result, format!("={:02X}", *v).as_bytes(), &mut on_line, &mut backup_pos);
}
None => break,
};
}
result
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn test_decode() {
assert_eq!("hello world",
String::from_utf8(decode_str("hello world", ParseMode::Strict).unwrap())
.unwrap());
assert_eq!("Now's the time for all folk to come to the aid of their country.",
String::from_utf8(decode_str("Now's the time =\r\nfor all folk to come=\r\n \
to the aid of their country.",
ParseMode::Strict)
.unwrap())
.unwrap());
assert_eq!("\r\nhello=world",
String::from_utf8(decode_str("=0D=0Ahello=3Dworld", ParseMode::Strict)
.unwrap())
.unwrap());
assert_eq!("hello world\r\ngoodbye world",
String::from_utf8(decode_str("hello world\r\ngoodbye world",
ParseMode::Strict)
.unwrap())
.unwrap());
assert_eq!("hello world\r\ngoodbye world",
String::from_utf8(decode_str("hello world \r\ngoodbye world ",
ParseMode::Strict)
.unwrap())
.unwrap());
assert_eq!("hello world\r\ngoodbye world x",
String::from_utf8(decode_str("hello world \r\ngoodbye world = \r\nx",
ParseMode::Strict)
.unwrap())
.unwrap());
assert_eq!(true,
decode_str("hello world=x", ParseMode::Strict).is_err());
assert_eq!("hello world=x",
String::from_utf8(decode_str("hello world=x", ParseMode::Robust).unwrap())
.unwrap());
assert_eq!(true,
decode_str("hello =world=", ParseMode::Strict).is_err());
assert_eq!("hello =world",
String::from_utf8(decode_str("hello =world=", ParseMode::Robust).unwrap())
.unwrap());
assert_eq!(true,
decode_str("hello world=3d", ParseMode::Strict).is_err());
assert_eq!("hello world=",
String::from_utf8(decode_str("hello world=3d", ParseMode::Robust).unwrap())
.unwrap());
assert_eq!(true,
decode_str("hello world=3m", ParseMode::Strict).is_err());
assert_eq!("hello world=3m",
String::from_utf8(decode_str("hello world=3m", ParseMode::Robust).unwrap())
.unwrap());
assert_eq!(true,
decode_str("hello\u{FF}world", ParseMode::Strict).is_err());
assert_eq!("helloworld",
String::from_utf8(decode_str("hello\u{FF}world", ParseMode::Robust).unwrap())
.unwrap());
assert_eq!(true,
decode_str("12345678901234567890123456789012345678901234567890123456789012345678901234567", ParseMode::Strict).is_err());
assert_eq!("12345678901234567890123456789012345678901234567890123456789012345678901234567",
String::from_utf8(decode_str("12345678901234567890123456789012345678901234567890123456789012345678901234567", ParseMode::Robust).unwrap()).unwrap());
assert_eq!("1234567890123456789012345678901234567890123456789012345678901234567890123456",
String::from_utf8(decode_str("1234567890123456789012345678901234567890123456789012345678901234567890123456", ParseMode::Strict).unwrap()).unwrap());
}
#[test]
fn test_encode() {
assert_eq!("hello, world!",
String::from_utf8(encode("hello, world!".as_bytes())).unwrap());
assert_eq!("hello,=0Cworld!",
String::from_utf8(encode("hello,\u{c}world!".as_bytes())).unwrap());
assert_eq!("this=00is=C3=BFa=3Dlong=0Dstring=0Athat gets wrapped and stuff, \
woohoo!=C3=\r\n=89",
String::from_utf8(encode("this\u{0}is\u{FF}a=long\rstring\nthat gets \
wrapped and stuff, woohoo!\u{c9}"
.as_bytes()))
.unwrap());
assert_eq!("this=00is=C3=BFa=3Dlong=0Dstring=0Athat just fits in a line, woohoo!=C3=89",
String::from_utf8(encode("this\u{0}is\u{FF}a=long\rstring\nthat just fits \
in a line, woohoo!\u{c9}"
.as_bytes()))
.unwrap());
assert_eq!("this \r\nhas linebreaks\r\n built right in.",
String::from_utf8(encode("this \r\nhas linebreaks\r\n built right in."
.as_bytes()))
.unwrap());
assert_eq!("XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXY",
String::from_utf8(encode("XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXY".as_bytes()))
.unwrap());
assert_eq!("XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX=\r\nXY",
String::from_utf8(encode("XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXY".as_bytes()))
.unwrap());
assert_eq!("XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX=\r\nXXY",
String::from_utf8(encode("XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXY".as_bytes()))
.unwrap());
assert_eq!("XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX=00Y",
String::from_utf8(encode("XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX\u{0}Y".as_bytes()))
.unwrap());
assert_eq!("XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX=\r\n=00Y",
String::from_utf8(encode("XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX\u{0}Y".as_bytes()))
.unwrap());
assert_eq!("XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX=\r\n=00Y",
String::from_utf8(encode("XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX\u{0}Y".as_bytes()))
.unwrap());
assert_eq!("XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX=\r\n=00Y",
String::from_utf8(encode("XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX\u{0}Y".as_bytes()))
.unwrap());
assert_eq!("=0D=3D",
String::from_utf8(encode("\r=".as_bytes())).unwrap());
}
}