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Return error for unterminated varint (Fix #9) #10

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Merged
dermesser merged 1 commit into from
Aug 30, 2020
Merged

Return error for unterminated varint (Fix #9) #10

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6 changes: 3 additions & 3 deletions src/lib.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -11,7 +11,7 @@
//!
//! let b: i32 = -111;
//! let encoded_byte_vec = b.encode_var_vec();
//! assert_eq!((b, 2), i32::decode_var(&encoded_byte_vec));
//! assert_eq!(Some((b, 2)), i32::decode_var(&encoded_byte_vec));
//! }
//! ```

Expand All @@ -29,14 +29,14 @@ pub use varint::VarInt;

#[cfg(any(feature = "tokio_async", feature = "futures_async"))]
pub use reader::FixedIntAsyncReader;
pub use reader::FixedIntReader;
#[cfg(any(feature = "tokio_async", feature = "futures_async"))]
pub use reader::VarIntAsyncReader;
pub use reader::FixedIntReader;
pub use reader::VarIntReader;

#[cfg(any(feature = "tokio_async", feature = "futures_async"))]
pub use writer::FixedIntAsyncWriter;
pub use writer::FixedIntWriter;
#[cfg(any(feature = "tokio_async", feature = "futures_async"))]
pub use writer::VarIntAsyncWriter;
pub use writer::FixedIntWriter;
pub use writer::VarIntWriter;
8 changes: 4 additions & 4 deletions src/reader.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -50,10 +50,10 @@ impl VarIntProcessor {
Ok(())
}
fn finished(&self) -> bool {
(self.i > 0 && (self.buf[self.i - 1] & MSB == 0))
self.i > 0 && (self.buf[self.i - 1] & MSB == 0)
}
fn decode<VI: VarInt>(&self) -> VI {
VI::decode_var(&self.buf[0..self.i]).0
fn decode<VI: VarInt>(&self) -> Option<VI> {
Some(VI::decode_var(&self.buf[0..self.i])?.0)
}
}

Expand Down Expand Up @@ -101,7 +101,7 @@ impl<R: Read> VarIntReader for R {
p.push(buf[0])?;
}

Ok(p.decode())
p.decode().ok_or_else(|| io::Error::new(io::ErrorKind::UnexpectedEof, "Reached EOF"))
}
}

Expand Down
40 changes: 26 additions & 14 deletions src/varint.rs
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Original file line number Diff line number Diff line change
@@ -1,4 +1,3 @@

/// Most-significant byte, == 0x80
pub const MSB: u8 = 0b1000_0000;
const DROP_MSB: u8 = 0b0111_1111;
Expand Down Expand Up @@ -31,7 +30,8 @@ pub trait VarInt: Sized + Copy {
fn required_space(self) -> usize;
/// Decode a value from the slice. Returns the value and the number of bytes read from the
/// slice (can be used to read several consecutive values from a big slice)
fn decode_var(src: &[u8]) -> (Self, usize);
/// return None if all bytes has MSB set.
fn decode_var(src: &[u8]) -> Option<(Self, usize)>;
/// Encode a value into the slice. The slice must be at least `required_space()` bytes long.
/// The number of bytes taken by the encoded integer is returned.
fn encode_var(self, src: &mut [u8]) -> usize;
Expand Down Expand Up @@ -66,9 +66,9 @@ macro_rules! impl_varint {
required_encoded_space_unsigned(self as u64)
}

fn decode_var(src: &[u8]) -> (Self, usize) {
let (n, s) = u64::decode_var(src);
(n as Self, s)
fn decode_var(src: &[u8]) -> Option<(Self, usize)> {
let (n, s) = u64::decode_var(src)?;
Some((n as Self, s))
}

fn encode_var(self, dst: &mut [u8]) -> usize {
Expand All @@ -82,9 +82,9 @@ macro_rules! impl_varint {
required_encoded_space_signed(self as i64)
}

fn decode_var(src: &[u8]) -> (Self, usize) {
let (n, s) = i64::decode_var(src);
(n as Self, s)
fn decode_var(src: &[u8]) -> Option<(Self, usize)> {
let (n, s) = i64::decode_var(src)?;
Some((n as Self, s))
}

fn encode_var(self, dst: &mut [u8]) -> usize {
Expand Down Expand Up @@ -112,10 +112,16 @@ impl VarInt for u64 {
required_encoded_space_unsigned(self)
}

fn decode_var(src: &[u8]) -> (Self, usize) {
fn decode_var(src: &[u8]) -> Option<(Self, usize)> {
let mut result: u64 = 0;
let mut shift = 0;

if let Some(b) = src.last() {
if b & MSB != 0 {
return None;
}
}

for b in src.iter() {
let msb_dropped = b & DROP_MSB;
result |= (msb_dropped as u64) << shift;
Expand All @@ -126,7 +132,7 @@ impl VarInt for u64 {
}
}

(result, shift / 7 as usize)
Some((result, shift / 7 as usize))
}

#[inline]
Expand All @@ -142,7 +148,7 @@ impl VarInt for u64 {
}

dst[i] = n as u8;
i+1
i + 1
}
}

Expand All @@ -151,10 +157,16 @@ impl VarInt for i64 {
required_encoded_space_signed(self)
}

fn decode_var(src: &[u8]) -> (Self, usize) {
fn decode_var(src: &[u8]) -> Option<(Self, usize)> {
let mut result: u64 = 0;
let mut shift = 0;

if let Some(b) = src.last() {
if b & MSB != 0 {
return None;
}
}

for b in src.iter() {
let msb_dropped = b & DROP_MSB;
result |= (msb_dropped as u64) << shift;
Expand All @@ -165,7 +177,7 @@ impl VarInt for i64 {
}
}

(zigzag_decode(result) as Self, shift / 7 as usize)
Some((zigzag_decode(result) as Self, shift / 7 as usize))
}

#[inline]
Expand All @@ -181,6 +193,6 @@ impl VarInt for i64 {
}

dst[i] = n as u8;
i+1
i + 1
}
}
12 changes: 6 additions & 6 deletions src/varint_tests.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -28,18 +28,18 @@ mod tests {
#[test]
fn test_identity_u64() {
for i in 1 as u64..100 {
assert_eq!(u64::decode_var(i.encode_var_vec().as_slice()), (i, 1));
assert_eq!(u64::decode_var(i.encode_var_vec().as_slice()).unwrap(), (i, 1));
}
for i in 16400 as u64..16500 {
assert_eq!(u64::decode_var(&i.encode_var_vec().as_slice()), (i, 3));
assert_eq!(u64::decode_var(&i.encode_var_vec().as_slice()).unwrap(), (i, 3));
}
}

#[test]
fn test_decode_max_u64() {
let max_vec_encoded = vec![0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0x01];
assert_eq!(
u64::decode_var(max_vec_encoded.as_slice()).0,
u64::decode_var(max_vec_encoded.as_slice()).unwrap().0,
u64::max_value()
);
}
Expand Down Expand Up @@ -70,7 +70,7 @@ mod tests {
fn test_decode_min_i64() {
let min_vec_encoded = vec![0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0x01];
assert_eq!(
i64::decode_var(min_vec_encoded.as_slice()).0,
i64::decode_var(min_vec_encoded.as_slice()).unwrap().0,
i64::min_value()
);
}
Expand All @@ -79,7 +79,7 @@ mod tests {
fn test_decode_max_i64() {
let max_vec_encoded = vec![0xFE, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0x01];
assert_eq!(
i64::decode_var(max_vec_encoded.as_slice()).0,
i64::decode_var(max_vec_encoded.as_slice()).unwrap().0,
i64::max_value()
);
}
Expand Down Expand Up @@ -158,6 +158,6 @@ mod tests {
fn test_unterminated_varint_2() {
let buf = [0xff, 0xff];
let mut read = &buf[..];
assert_eq!(16383, read.read_varint::<u64>().unwrap());
assert!(read.read_varint::<u64>().is_err());
}
}