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#[derive(Debug, PartialEq)]
pub(super) enum BenToken {
ByteString(usize, usize), // begin, end
Number(isize),
Dict(usize),
List(usize),
None
}
impl BenToken {
pub(super) fn len(&self) -> usize {
return match self {
Self::ByteString(_, _) => 1,
Self::Dict(len) | Self::List(len) => *len,
Self::Number(_) => 1,
Self::None => 1
};
}
}
#[derive(PartialEq)]
pub(super) enum BenTokenIndex {
Dict(usize),
List(usize)
}
pub(super) fn tokenize(bytes: &[u8], tokens: &mut Vec<BenToken>, indices: &mut Vec<BenTokenIndex>) -> bool {
let mut offset = 0usize;
let mut b;
while offset < bytes.len() {
b = bytes[offset];
match b {
0x30..=0x39 => {
let mut len = b.wrapping_sub(0x30) as usize;
offset += 1;
while offset < bytes.len() {
b = bytes[offset];
offset += 1;
if b != b':' {
len = len.wrapping_mul(10)
.wrapping_add(b.wrapping_sub(0x30) as usize);
} else {
break;
}
}
if offset + len < bytes.len() {
tokens.push(BenToken::ByteString(offset, offset+len));
offset += len;
continue;
} else {
return false;
}
},
b'e' => {
match indices.pop() {
Some(BenTokenIndex::Dict(idx)) => {
tokens[idx] = BenToken::Dict(tokens.len() - idx);
},
Some(BenTokenIndex::List(idx)) => {
tokens[idx] = BenToken::List(tokens.len() - idx);
},
None => return false
}
},
b'd' => {
indices.push(BenTokenIndex::Dict(tokens.len()));
tokens.push(BenToken::None);
},
b'l' => {
indices.push(BenTokenIndex::List(tokens.len()));
tokens.push(BenToken::None);
},
b'i' => {
offset += 1;
// Check sign.
if offset < bytes.len() {
b = bytes[offset];
// Negative number
if b == b'-' {
offset += 1;
if offset >= bytes.len() {
return false;
}
b = bytes[offset];
let mut num = -(b.wrapping_sub(0x30) as isize);
loop {
offset += 1;
if offset >= bytes.len() {
return false;
}
b = bytes[offset];
if b != b'e' {
num = num.wrapping_mul(10).wrapping_sub(b.wrapping_sub(0x30) as isize);
} else {
break;
}
}
tokens.push(BenToken::Number(num));
// Positive number
} else {
let mut num = b.wrapping_sub(0x30) as isize;
loop {
offset += 1;
if offset >= bytes.len() {
return false;
}
b = bytes[offset];
if b != b'e' {
num = num.wrapping_mul(10).wrapping_add(b.wrapping_sub(0x30) as isize);
} else {
break;
}
}
tokens.push(BenToken::Number(num));
}
}
},
_ => return false
}
if indices.len() == 0 {
return true;
}
offset += 1;
}
return false;
}