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Fix varint and varlong decoding #238

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Fix varint and varlong decoding #238

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abfcd57
Fix varint decoding
terrarier2111 Mar 4, 2022
23e2e71
Fix varint/varlong decoding/encoding
byte-sized-emi May 11, 2022
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51 changes: 26 additions & 25 deletions protocol/src/protocol/mod.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -891,37 +891,37 @@ impl Lengthable for VarInt {
}
}

const VARINT_SEGMENT_BITS: u32 = 0b0111_1111;
const VARINT_CONTINUE_BIT: u32 = 0b1000_0000;

impl Serializable for VarInt {
/// Decodes a `VarInt` from the Reader
fn read_from<R: io::Read>(buf: &mut R) -> Result<VarInt, Error> {
const PART: u32 = 0x7F;
let mut size = 0;
let mut position = 0;
let mut val = 0u32;
loop {
let b = buf.read_u8()? as u32;
val |= (b & PART) << (size * 7);
size += 1;
if size > 5 {
return Err(Error::Err("VarInt too big".to_owned()));
}
if (b & 0x80) == 0 {
let current_byte = buf.read_u8()? as u32;
val |= (current_byte & VARINT_SEGMENT_BITS) << position;
if (current_byte & VARINT_CONTINUE_BIT) == 0 {
break;
}
position += 7;
if position >= 32 {
return Err(Error::Err("VarInt too big".to_owned()));
}
}

Ok(VarInt(val as i32))
}

/// Encodes a `VarInt` into the Writer
fn write_to<W: io::Write>(&self, buf: &mut W) -> Result<(), Error> {
const PART: u32 = 0x7F;
let mut val = self.0 as u32;
loop {
if (val & !PART) == 0 {
if (val & VARINT_CONTINUE_BIT) == 0 {
buf.write_u8(val as u8)?;
return Ok(());
}
buf.write_u8(((val & PART) | 0x80) as u8)?;
buf.write_u8(((val & VARINT_SEGMENT_BITS) | VARINT_CONTINUE_BIT) as u8)?;
val >>= 7;
}
}
Expand Down Expand Up @@ -1017,37 +1017,38 @@ impl Lengthable for VarLong {
}
}

const VARLONG_SEGMENT_BITS: u64 = 0b0111_1111;
const VARLONG_CONTINUE_BIT: u64 = 0b1000_0000;

impl Serializable for VarLong {
/// Decodes a `VarLong` from the Reader
fn read_from<R: io::Read>(buf: &mut R) -> Result<VarLong, Error> {
const PART: u64 = 0x7F;
let mut size = 0;
let mut position = 0;
let mut val = 0u64;
loop {
let b = buf.read_u8()? as u64;
val |= (b & PART) << (size * 7);
size += 1;
if size > 10 {
return Err(Error::Err("VarLong too big".to_owned()));
}
if (b & 0x80) == 0 {
let current_byte = buf.read_u8()? as u64;
val |= (current_byte & VARLONG_SEGMENT_BITS) << position;
if (current_byte & VARLONG_CONTINUE_BIT) == 0 {
break;
}
position += 7;
if position >= 64 {
return Err(Error::Err("VarLong too big".to_owned()));
}
}

Ok(VarLong(val as i64))
}

/// Encodes a `VarLong` into the Writer
fn write_to<W: io::Write>(&self, buf: &mut W) -> Result<(), Error> {
const PART: u64 = 0x7F;
let mut val = self.0 as u64;
loop {
if (val & !PART) == 0 {
if (val & VARLONG_CONTINUE_BIT) == 0 {
buf.write_u8(val as u8)?;
return Ok(());
}
buf.write_u8(((val & PART) | 0x80) as u8)?;
buf.write_u8(((val & VARLONG_SEGMENT_BITS) | VARLONG_CONTINUE_BIT) as u8)?;
val >>= 7;
}
}
Expand Down