ring/io/
writer.rs

1// Copyright 2018 Brian Smith.
2//
3// Permission to use, copy, modify, and/or distribute this software for any
4// purpose with or without fee is hereby granted, provided that the above
5// copyright notice and this permission notice appear in all copies.
6//
7// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHORS DISCLAIM ALL WARRANTIES
8// WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
9// MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY
10// SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
11// WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
12// OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
13// CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
14
15use alloc::{boxed::Box, vec::Vec};
16
17pub trait Accumulator {
18    fn write_byte(&mut self, value: u8);
19    fn write_bytes(&mut self, value: &[u8]);
20}
21
22pub(super) struct LengthMeasurement {
23    len: usize,
24}
25
26impl From<LengthMeasurement> for usize {
27    fn from(len: LengthMeasurement) -> usize {
28        len.len
29    }
30}
31
32impl LengthMeasurement {
33    pub fn zero() -> Self {
34        Self { len: 0 }
35    }
36}
37
38impl Accumulator for LengthMeasurement {
39    fn write_byte(&mut self, _value: u8) {
40        self.len += 1;
41    }
42    fn write_bytes(&mut self, value: &[u8]) {
43        self.len += value.len();
44    }
45}
46
47pub(super) struct Writer {
48    bytes: Vec<u8>,
49    requested_capacity: usize,
50}
51
52impl Writer {
53    pub(super) fn with_capacity(capacity: LengthMeasurement) -> Self {
54        Self {
55            bytes: Vec::with_capacity(capacity.len),
56            requested_capacity: capacity.len,
57        }
58    }
59}
60
61impl From<Writer> for Box<[u8]> {
62    fn from(writer: Writer) -> Self {
63        assert_eq!(writer.requested_capacity, writer.bytes.len());
64        writer.bytes.into_boxed_slice()
65    }
66}
67
68impl Accumulator for Writer {
69    fn write_byte(&mut self, value: u8) {
70        self.bytes.push(value);
71    }
72    fn write_bytes(&mut self, value: &[u8]) {
73        self.bytes.extend(value);
74    }
75}
76
77pub fn write_copy(accumulator: &mut dyn Accumulator, to_copy: untrusted::Input) {
78    accumulator.write_bytes(to_copy.as_slice_less_safe())
79}
ring/io/writer.rs

ring/io/
writer.rs
