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
15 use alloc::{boxed::Box, vec::Vec};
16
17 pub trait Accumulator {
write_byte(&mut self, value: u8)18 fn write_byte(&mut self, value: u8);
write_bytes(&mut self, value: &[u8])19 fn write_bytes(&mut self, value: &[u8]);
20 }
21
22 pub(super) struct LengthMeasurement {
23 len: usize,
24 }
25
26 impl Into<usize> for LengthMeasurement {
into(self) -> usize27 fn into(self) -> usize {
28 self.len
29 }
30 }
31
32 impl LengthMeasurement {
zero() -> Self33 pub fn zero() -> Self {
34 Self { len: 0 }
35 }
36 }
37
38 impl Accumulator for LengthMeasurement {
write_byte(&mut self, _value: u8)39 fn write_byte(&mut self, _value: u8) {
40 self.len += 1;
41 }
write_bytes(&mut self, value: &[u8])42 fn write_bytes(&mut self, value: &[u8]) {
43 self.len += value.len();
44 }
45 }
46
47 pub(super) struct Writer {
48 bytes: Vec<u8>,
49 requested_capacity: usize,
50 }
51
52 impl Writer {
with_capacity(capacity: LengthMeasurement) -> Self53 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
61 impl Into<Box<[u8]>> for Writer {
into(self) -> Box<[u8]>62 fn into(self) -> Box<[u8]> {
63 assert_eq!(self.requested_capacity, self.bytes.len());
64 self.bytes.into_boxed_slice()
65 }
66 }
67
68 impl Accumulator for Writer {
write_byte(&mut self, value: u8)69 fn write_byte(&mut self, value: u8) {
70 self.bytes.push(value);
71 }
write_bytes(&mut self, value: &[u8])72 fn write_bytes(&mut self, value: &[u8]) {
73 self.bytes.extend(value);
74 }
75 }
76
write_copy(accumulator: &mut dyn Accumulator, to_copy: untrusted::Input)77 pub fn write_copy(accumulator: &mut dyn Accumulator, to_copy: untrusted::Input) {
78 accumulator.write_bytes(to_copy.as_slice_less_safe())
79 }
80