numbat_codec/
nested_de_input.rs

1pub use crate::codec_err::DecodeError;
2
3/// Trait that allows reading of data into a slice.
4pub trait NestedDecodeInput {
5	/// The remaining length of the input data.
6	fn remaining_len(&mut self) -> usize;
7
8	fn empty(&mut self) -> bool {
9		self.remaining_len() == 0
10	}
11
12	/// Read the exact number of bytes required to fill the given buffer.
13	fn read_into(&mut self, into: &mut [u8]) -> Result<(), DecodeError>;
14
15	/// Read the exact number of bytes required to fill the given buffer.
16	/// Exit early if there are not enough bytes to fill the result.
17	fn read_into_or_exit<ExitCtx: Clone>(
18		&mut self,
19		into: &mut [u8],
20		c: ExitCtx,
21		exit: fn(ExitCtx, DecodeError) -> !,
22	);
23
24	/// Read a single byte from the input.
25	fn read_byte(&mut self) -> Result<u8, DecodeError> {
26		let mut buf = [0u8];
27		self.read_into(&mut buf[..])?;
28		Ok(buf[0])
29	}
30
31	/// Read a single byte from the input.
32	fn read_byte_or_exit<ExitCtx: Clone>(
33		&mut self,
34		c: ExitCtx,
35		exit: fn(ExitCtx, DecodeError) -> !,
36	) -> u8 {
37		let mut buf = [0u8];
38		self.read_into_or_exit(&mut buf[..], c, exit);
39		buf[0]
40	}
41
42	/// Read the exact number of bytes required to fill the given buffer.
43	fn read_slice(&mut self, length: usize) -> Result<&[u8], DecodeError>;
44
45	/// Read the exact number of bytes required to fill the given buffer.
46	/// Exit directly if the input contains too few bytes.
47	fn read_slice_or_exit<ExitCtx: Clone>(
48		&mut self,
49		length: usize,
50		c: ExitCtx,
51		exit: fn(ExitCtx, DecodeError) -> !,
52	) -> &[u8];
53
54	/// Clears the input buffer and returns all remaining bytes.
55	fn flush(&mut self) -> &[u8];
56}
57
58impl<'a> NestedDecodeInput for &'a [u8] {
59	fn remaining_len(&mut self) -> usize {
60		self.len()
61	}
62
63	fn read_into(&mut self, into: &mut [u8]) -> Result<(), DecodeError> {
64		if into.len() > self.len() {
65			return Err(DecodeError::INPUT_TOO_SHORT);
66		}
67		let len = into.len();
68		into.copy_from_slice(&self[..len]);
69		*self = &self[len..];
70		Ok(())
71	}
72
73	fn read_into_or_exit<ExitCtx: Clone>(
74		&mut self,
75		into: &mut [u8],
76		c: ExitCtx,
77		exit: fn(ExitCtx, DecodeError) -> !,
78	) {
79		if into.len() > self.len() {
80			exit(c, DecodeError::INPUT_TOO_SHORT);
81		}
82		let len = into.len();
83		into.copy_from_slice(&self[..len]);
84		*self = &self[len..];
85	}
86
87	fn read_slice(&mut self, length: usize) -> Result<&[u8], DecodeError> {
88		if length > self.len() {
89			return Err(DecodeError::INPUT_TOO_SHORT);
90		}
91
92		let (result, rest) = self.split_at(length);
93		*self = rest;
94		Ok(result)
95	}
96
97	fn read_slice_or_exit<ExitCtx: Clone>(
98		&mut self,
99		length: usize,
100		c: ExitCtx,
101		exit: fn(ExitCtx, DecodeError) -> !,
102	) -> &[u8] {
103		if length > self.len() {
104			exit(c, DecodeError::INPUT_TOO_SHORT);
105		}
106
107		let (result, rest) = self.split_at(length);
108		*self = rest;
109		result
110	}
111
112	fn flush(&mut self) -> &[u8] {
113		let result = &self[..];
114		*self = &[];
115		result
116	}
117}
numbat_codec/nested_de_input.rs

numbat_codec/
nested_de_input.rs
