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fix mutf-8 codec #40

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Merged
hayanesuru merged 2 commits into from
Feb 15, 2026
Merged

fix mutf-8 codec #40

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86291d6
fix mutf-8 codec
hayanesuru Feb 15, 2026
324266f
fix C0 80 decode
hayanesuru Feb 15, 2026
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41 changes: 33 additions & 8 deletions haya_mutf8/src/lib.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -136,14 +136,25 @@ pub fn decode_mutf8_len(mut bytes: &[u8]) -> Result<usize, Error> {
bytes = rest;
match byte {
0x01..=0x7F => len += 1,
0xC2..=0xDF => {
0xC0 => {
if let [sec, ref rest @ ..] = bytes[..] {
bytes = rest;
if !(byte == 0xC0 && sec == 0x80) {
len += 2;
} else {
if sec == 0x80 {
len += 1;
} else {
return Err(Error);
}
} else {
return Err(Error);
}
}
0xC2..=0xDF => {
if let [sec, ref rest @ ..] = bytes[..] {
bytes = rest;
if sec as i8 >= -64 {
return Err(Error);
}
len += 2;
} else {
return Err(Error);
}
Expand Down Expand Up @@ -197,19 +208,30 @@ pub unsafe fn decode_mutf8(Mutf8(bytes): Mutf8, w: &mut UnsafeWriter) -> Result<
while let Some(&byte) = bytes.get(index) {
match byte {
0x01..=0x7F => index += 1,
0xC2..=0xDF => unsafe {
0xC0 => unsafe {
let sec = match bytes.get(index + 1) {
Some(&byte) => byte,
_ => return Err(Error),
};
index += 2;
if !(byte == 0xC0 && sec == 0x80) {
} else {
if sec == 0x80 {
w.write(bytes.get_unchecked(start..index));
w.write_byte(b'\0');
index += 2;
start = index;
} else {
return Err(Error);
}
},
0xC2..=0xDF => {
let sec = match bytes.get(index + 1) {
Some(&byte) => byte,
_ => return Err(Error),
};
if sec as i8 >= -64 {
return Err(Error);
}
index += 2;
}
0xE0..=0xEF => unsafe {
let sec = match bytes.get(index + 1) {
Some(&byte) if byte & 0xC0 == 0x80 => byte,
Expand Down Expand Up @@ -241,12 +263,15 @@ pub unsafe fn decode_mutf8(Mutf8(bytes): Mutf8, w: &mut UnsafeWriter) -> Result<
let s1 = 0xD000 | (u32::from(sec & 0x3F) << 6) | u32::from(third & 0x3F);
let s2 = 0xD000 | (u32::from(fifth) << 6) | u32::from(sixth);
let point = 0x10000 + (((s1 - 0xD800) << 10) | (s2 - 0xDC00));
w.write(bytes.get_unchecked(start..index));
w.write(&[
0xF0 | ((point & 0x1C0000) >> 18) as u8,
0x80 | ((point & 0x3F000) >> 12) as u8,
0x80 | ((point & 0xFC0) >> 6) as u8,
0x80 | (point & 0x3F) as u8,
]);
index += 6;
start = index;
}
_ => return Err(Error),
}
Expand Down