prost/encoding/
length_delimiter.rs

1use crate::error::DecodeErrorKind;
2pub use crate::error::{DecodeError, EncodeError, UnknownEnumValue};
3pub use crate::message::Message;
4pub use crate::name::Name;
5
6use bytes::{Buf, BufMut};
7
8use crate::encoding::varint::{decode_varint, encode_varint, encoded_len_varint};
9
10/// Encodes a length delimiter to the buffer.
11///
12/// See [Message.encode_length_delimited] for more info.
13///
14/// An error will be returned if the buffer does not have sufficient capacity to encode the
15/// delimiter.
16pub fn encode_length_delimiter(length: usize, buf: &mut impl BufMut) -> Result<(), EncodeError> {
17    let length = length as u64;
18    let required = encoded_len_varint(length);
19    let remaining = buf.remaining_mut();
20    if required > remaining {
21        return Err(EncodeError::new(required, remaining));
22    }
23    encode_varint(length, buf);
24    Ok(())
25}
26
27/// Returns the encoded length of a length delimiter.
28///
29/// Applications may use this method to ensure sufficient buffer capacity before calling
30/// `encode_length_delimiter`. The returned size will be between 1 and 10, inclusive.
31pub fn length_delimiter_len(length: usize) -> usize {
32    encoded_len_varint(length as u64)
33}
34
35/// Decodes a length delimiter from the buffer.
36///
37/// This method allows the length delimiter to be decoded independently of the message, when the
38/// message is encoded with [Message.encode_length_delimited].
39///
40/// An error may be returned in two cases:
41///
42///  * If the supplied buffer contains fewer than 10 bytes, then an error indicates that more
43///    input is required to decode the full delimiter.
44///  * If the supplied buffer contains 10 bytes or more, then the buffer contains an invalid
45///    delimiter, and typically the buffer should be considered corrupt.
46pub fn decode_length_delimiter(mut buf: impl Buf) -> Result<usize, DecodeError> {
47    let length = decode_varint(&mut buf)?;
48    if length > usize::MAX as u64 {
49        return Err(DecodeErrorKind::LengthDelimiterTooLarge.into());
50    }
51    Ok(length as usize)
52}
prost/encoding/length_delimiter.rs

prost/encoding/
length_delimiter.rs
