Struct s2n_codec::decoder::buffer::DecoderBuffer

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pub struct DecoderBuffer<'a> { /* private fields */ }

Expand description

DecoderBuffer is a panic-free byte buffer for look-ahead decoding untrusted input

Implementations§

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impl<'a> DecoderBuffer<'a>

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pub const fn new(bytes: &'a [u8]) -> Self

Create a new DecoderBuffer from a byte slice

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pub fn into_less_safe_slice(self) -> &'a [u8] ⓘ

Move out the buffer’s slice. This should be used with caution, as it removes any panic protection this struct provides.

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impl<'a> DecoderBuffer<'a>

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pub fn decode_slice( self, count: usize ) -> DecoderBufferResult<'a, DecoderBuffer<'a>>

Decode a slice of bytes by count, removing the slice from the current buffer

let mut data = [0, 1, 2, 3, 4];
let buffer = DecoderBuffer::new(&mut data);

let (slice, buffer) = buffer.decode_slice(5).unwrap();
assert_eq!(slice, [0u8, 1, 2, 3, 4][..]);

assert!(buffer.is_empty());

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pub fn decode<T: DecoderValue<'a>>(self) -> DecoderBufferResult<'a, T>

Decode a value of type T, splitting the data from the current buffer

let mut data = [0, 1, 2, 3, 4, 5, 6];
let buffer = DecoderBuffer::new(&mut data);

let (value, buffer) = buffer.decode::<u8>().unwrap();
assert_eq!(value, 0);

let (value, buffer) = buffer.decode::<u16>().unwrap();
assert_eq!(value, 258);

let (value, buffer) = buffer.decode::<u32>().unwrap();
assert_eq!(value, 50_595_078);

assert!(buffer.is_empty());

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pub fn decode_slice_with_len_prefix<Length: DecoderValue<'a> + TryInto<usize>>( self ) -> DecoderBufferResult<'a, Self>

Decode a slice prefixed by type Length, splitting the data from the current buffer. With a Length as encoded u8:

let mut data = [5, 0, 1, 2, 3, 4];
let buffer = DecoderBuffer::new(&mut data);
let (slice, buffer) = buffer.decode_slice_with_len_prefix::<u8>().unwrap();
assert_eq!(slice, [0u8, 1, 2, 3, 4][..]);
assert!(buffer.is_empty())

With a Length as encoded u16:

let mut data = [0, 5, 0, 1, 2, 3, 4];
let buffer = DecoderBuffer::new(&mut data);
let (slice, buffer) = buffer.decode_slice_with_len_prefix::<u16>().unwrap();
assert_eq!(slice, [0u8, 1, 2, 3, 4][..]);
assert!(buffer.is_empty())

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pub fn decode_with_len_prefix<Length: DecoderValue<'a> + TryInto<usize>, T: DecoderValue<'a>>( self ) -> DecoderBufferResult<'a, T>

Decode a value of type T prefixed by type Length, splitting the data from the current buffer. With a Length as encoded u8 and T as u16:

let mut data = [2, 0, 1, 2, 3];
let buffer = DecoderBuffer::new(&mut data);
let (value, buffer) = buffer.decode_with_len_prefix::<u8, u16>().unwrap();
assert_eq!(value, 1);
assert_eq!(buffer, [2, 3][..])

The DecoderValue implementation of T must consume the entire subslice otherwise an error will be returned.

let mut data = [3, 0, 1, 2];
let buffer = DecoderBuffer::new(&mut data);
let result = buffer.decode_with_len_prefix::<u8, u16>();
assert!(result.is_err())

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pub fn decode_parameterized<T: DecoderParameterizedValue<'a>>( self, parameter: T::Parameter ) -> DecoderBufferResult<'a, T>

Decode a parameterized value of type T implementing DecoderParameterizedValue

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pub fn skip(self, count: usize) -> Result<DecoderBuffer<'a>, DecoderError>

Skip a count of bytes, discarding the bytes

let mut data = [0, 1, 2, 3, 4];
let buffer = DecoderBuffer::new(&mut data);
let buffer = buffer.skip(3).unwrap();
assert_eq!(buffer, [3, 4][..]);

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pub fn skip_with_len_prefix<Length: DecoderValue<'a> + TryInto<usize>>( self ) -> Result<DecoderBuffer<'a>, DecoderError>

Skip a number of bytes encoded as a length prefix of type Length With a Length encoded as u8:

let mut data = [5, 0, 1, 2, 3, 4];
let buffer = DecoderBuffer::new(&mut data);
let buffer = buffer.skip_with_len_prefix::<u8>().unwrap();
assert!(buffer.is_empty());

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pub fn skip_into_range( self, count: usize, original_buffer: &DecoderBufferMut<'_> ) -> DecoderBufferResult<'a, CheckedRange>

Skip a count of bytes, returning a CheckedRange for later access

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pub fn skip_into_range_with_len_prefix<Length: DecoderValue<'a> + TryInto<usize>>( self, original_buffer: &DecoderBufferMut<'_> ) -> DecoderBufferResult<'a, CheckedRange>

Skip a number of bytes encoded as a length prefix of type Length into a CheckedRange for later access

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pub fn get_checked_range(&self, range: &CheckedRange) -> DecoderBuffer<'_>

Reads data from a CheckedRange

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pub fn peek(&'a self) -> DecoderBuffer<'a>

Create a peeking DecoderBuffer from the current buffer view

let mut data = [0, 1];
let buffer = DecoderBuffer::new(&mut data);

let peek = buffer.peek();
let (value, peek) = peek.decode::<u16>().unwrap();
assert_eq!(value, 1);
assert!(peek.is_empty());

// `buffer` still contains the previous view
assert_eq!(buffer, [0, 1][..]);

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pub fn peek_byte(&self, index: usize) -> Result<u8, DecoderError>

Returns a single byte at index

let mut data = [0, 1, 2];
let buffer = DecoderBuffer::new(&mut data);

assert_eq!(buffer.peek_byte(0).unwrap(), 0);
assert_eq!(buffer.peek_byte(1).unwrap(), 1);
assert_eq!(buffer.peek_byte(2).unwrap(), 2);

// `buffer` has not changed
assert_eq!(buffer, [0, 1, 2][..]);

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pub fn peek_range( &self, range: Range<usize> ) -> Result<DecoderBuffer<'_>, DecoderError>

Returns a PeekBuffer by range

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pub fn ensure_empty(&self) -> Result<(), DecoderError>

Returns an error if the buffer is not empty.

let mut data = [1];
let buffer = DecoderBuffer::new(&mut data);

assert!(buffer.ensure_empty().is_err());
let (_, buffer) = buffer.decode::<u8>().unwrap();
assert!(buffer.ensure_empty().is_ok());

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pub fn ensure_len(&self, len: usize) -> Result<(), DecoderError>

Returns an error if the buffer does not have at least len bytes.

let mut data = [0, 1, 2];
let buffer = DecoderBuffer::new(&mut data);

assert!(buffer.ensure_len(2).is_ok());
assert!(buffer.ensure_len(5).is_err());

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pub fn len(&self) -> usize

Returns the number of bytes in the buffer.

let mut data = [0, 1, 2];
let buffer = DecoderBuffer::new(&mut data);

assert_eq!(buffer.len(), 3);
let (_, buffer) = buffer.decode::<u8>().unwrap();
assert_eq!(buffer.len(), 2);

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pub fn is_empty(&self) -> bool

Returns true if the buffer has a length of 0.

let mut data = [1];
let buffer = DecoderBuffer::new(&mut data);

assert!(!buffer.is_empty());
let (_, buffer) = buffer.decode::<u8>().unwrap();
assert!(buffer.is_empty());

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