From 2be8445a9f65ca8028b147d051454e8d36f3be76 Mon Sep 17 00:00:00 2001
From: Stephen D <webmaster@scd31.com>
Date: Sun, 26 Nov 2023 13:25:38 -0400
Subject: [PATCH] remove lots of expensive stack allocations
---
src/buffer.rs | 68 +++++++++++++++++++++++++++++++++++------
src/interleaver.rs | 29 +++++++++++-------
src/ldpc.rs | 61 ++++++++++++++++---------------------
src/packet.rs | 75 ++++++++++++++++++++++++++--------------------
src/whitener.rs | 6 ++--
5 files changed, 148 insertions(+), 91 deletions(-)
diff --git a/src/buffer.rs b/src/buffer.rs
index a822d66..13db9ee 100644
--- a/src/buffer.rs
+++ b/src/buffer.rs
@@ -1,24 +1,33 @@
-use core::{borrow::Borrow, ops::Deref};
+use core::ops::{Deref, DerefMut};
-pub(crate) struct BufferOverflow;
+#[derive(Debug)]
+pub struct BufferOverflow;
-pub(crate) struct Buffer<'a, const N: usize> {
+#[derive(Debug)]
+pub struct Buffer<'a, const N: usize> {
data: &'a mut [u8; N],
i: usize,
}
impl<'a, const N: usize> Buffer<'a, N> {
+ /// Constructs a new `Buffer`.
+ /// `data` is the backing array.
+ /// `i` is the number of elements in `data` that contain data (and should thus be exposed by `Buffer`)
pub fn new(data: &'a mut [u8; N], i: usize) -> Self {
+ assert!(i <= data.len());
+
Self { data, i }
}
- /*pub fn as_slice(&self) -> &'a [u8] {
- &self.data[..self.i]
- }
+ pub fn new_full(data: &'a mut [u8; N]) -> Self {
+ let i = data.len();
+
+ Self::new(data, i)
+ }
- pub fn as_slice_mut(&mut self) -> &'a [u8] {
- &mut self.data[..self.i]
- }*/
+ pub fn new_empty(data: &'a mut [u8; N]) -> Self {
+ Self::new(data, 0)
+ }
pub const fn remaining_capacity(&self) -> usize {
N - self.i
@@ -35,6 +44,10 @@ impl<'a, const N: usize> Buffer<'a, N> {
Ok(())
}
+ pub fn push(&mut self, v: u8) {
+ self.try_push(v).unwrap();
+ }
+
pub fn try_extend_from_slice(&mut self, other: &[u8]) -> Result<(), BufferOverflow> {
if self.remaining_capacity() < other.len() {
return Err(BufferOverflow);
@@ -46,6 +59,10 @@ impl<'a, const N: usize> Buffer<'a, N> {
Ok(())
}
+ pub fn extend(&mut self, other: &[u8]) {
+ self.try_extend_from_slice(other).unwrap();
+ }
+
pub fn pop(&mut self) -> Option<u8> {
if self.i == 0 {
return None;
@@ -55,6 +72,33 @@ impl<'a, const N: usize> Buffer<'a, N> {
Some(self.data[self.i])
}
+
+ pub fn truncate(&mut self, new_len: usize) {
+ assert!(self.i >= new_len);
+
+ self.i = new_len;
+ }
+
+ pub fn drain(&mut self, start: usize, end: usize) {
+ assert!(end >= start);
+ assert!(end <= self.i);
+ let delta = end - start;
+ let surplus = self.len() - end;
+
+ for i in start..(start + surplus) {
+ self[i] = self[i + delta];
+ }
+
+ self.i -= delta;
+ }
+
+ pub fn clone_backing<'b>(&self, buf: &'b mut [u8; N]) -> Buffer<'b, N> {
+ let mut out = Buffer::new_empty(buf);
+
+ out.extend(self);
+
+ out
+ }
}
impl<'a, const N: usize> From<&'a mut [u8; N]> for Buffer<'a, N> {
@@ -70,3 +114,9 @@ impl<'a, const N: usize> Deref for Buffer<'a, N> {
&self.data[..self.i]
}
}
+
+impl<'a, const N: usize> DerefMut for Buffer<'a, N> {
+ fn deref_mut(&mut self) -> &mut [u8] {
+ &mut self.data[..self.i]
+ }
+}
diff --git a/src/interleaver.rs b/src/interleaver.rs
index 5661bb4..5efeaaf 100644
--- a/src/interleaver.rs
+++ b/src/interleaver.rs
@@ -1,11 +1,13 @@
-use arrayvec::{ArrayVec, CapacityError};
use bitvec::prelude::*;
-use crate::error::EncodeError;
+use crate::{
+ buffer::{Buffer, BufferOverflow},
+ error::EncodeError,
+};
pub(crate) fn interleave<const N: usize>(
data: &[u8],
- out: &mut ArrayVec<u8, N>,
+ out: &mut Buffer<N>,
) -> Result<(), EncodeError> {
let bv = data.view_bits::<Msb0>();
@@ -33,10 +35,10 @@ pub(crate) fn interleave<const N: usize>(
pub(crate) fn uninterleave<const N: usize>(
data: &[u8],
-) -> Result<ArrayVec<u8, N>, CapacityError<u8>> {
+ out: &mut Buffer<N>,
+) -> Result<(), BufferOverflow> {
let bv = data.view_bits::<Msb0>();
- let mut out: ArrayVec<u8, N> = ArrayVec::new();
for _ in 0..data.len() {
out.try_push(0)?;
}
@@ -55,7 +57,7 @@ pub(crate) fn uninterleave<const N: usize>(
}
}
- Ok(out)
+ Ok(())
}
#[cfg(test)]
@@ -64,17 +66,22 @@ mod tests {
#[test]
fn interleaver_works() {
- let orig =
- ArrayVec::try_from([0x84, 0x73, 0x12, 0xA3, 0xFF, 0x00, 0xC2, 0x1B, 0x77]).unwrap();
- let mut interleaved: ArrayVec<u8, 10> = ArrayVec::new();
+ let mut data = [0x84, 0x73, 0x12, 0xA3, 0xFF, 0x00, 0xC2, 0x1B, 0x77];
+ let orig = Buffer::new_full(&mut data);
+
+ let mut interleaved = [0; 10];
+ let mut interleaved = Buffer::new(&mut interleaved, 0);
interleaved.push(b'H');
+
interleave(&orig, &mut interleaved).unwrap();
let expected = [b'H', 0xCD, 0xB5, 0xDB, 0x2A, 0x0A, 0x52, 0x0C, 0x89, 0x4F];
assert_eq!(expected, interleaved[..]);
- let uninterleaved = uninterleave(&interleaved[1..]).unwrap();
+ let mut uninterleaved = [0; 10];
+ let mut uninterleaved = Buffer::new(&mut uninterleaved, 0);
+ uninterleave(&interleaved[1..], &mut uninterleaved).unwrap();
- assert_eq!(orig, uninterleaved);
+ assert_eq!(*orig, *uninterleaved);
}
}
diff --git a/src/ldpc.rs b/src/ldpc.rs
index 0c5c07e..a3cda75 100644
--- a/src/ldpc.rs
+++ b/src/ldpc.rs
@@ -1,4 +1,3 @@
-use arrayvec::ArrayVec;
use labrador_ldpc::LDPCCode;
use crate::{buffer::Buffer, error::EncodeError};
@@ -84,7 +83,7 @@ pub(crate) fn encode<const N: usize>(data: &mut Buffer<N>) -> Result<(), EncodeE
Ok(())
}
-pub(crate) fn decode<const N: usize>(data_av: &mut ArrayVec<u8, N>) -> Option<()> {
+pub(crate) fn decode<const N: usize>(data_av: &mut Buffer<N>) -> Option<()> {
if data_av.len() < 2 {
return None;
}
@@ -157,25 +156,18 @@ pub(crate) fn decode<const N: usize>(data_av: &mut ArrayVec<u8, N>) -> Option<()
#[cfg(test)]
mod tests {
use super::*;
- use arrayvec::ArrayVec;
#[test]
fn len_test() {
// from the example in the docs
- let mut data: ArrayVec<u8, 8191> = ArrayVec::new();
+ let mut buf = [0; 8191];
+ let mut data = Buffer::new_empty(&mut buf);
for _ in 0..41 {
- data.extend(
- b"Example packet data wueirpqwerwrywqoeiruy29346129384761"
- .iter()
- .cloned(),
- );
+ data.extend(b"Example packet data wueirpqwerwrywqoeiruy29346129384761");
}
- data.extend(
- b"Example packet data wueirpqwerwrywqoeiru346129384761"
- .iter()
- .cloned(),
- );
+ data.extend(b"Example packet data wueirpqwerwrywqoeiru346129384761");
+
assert_eq!(2349, data.len());
encode(&mut data).unwrap();
@@ -185,51 +177,50 @@ mod tests {
#[test]
fn basic_encode_decode_short() {
- let mut data: ArrayVec<u8, 32> = ArrayVec::new();
+ let mut buf = [0; 32];
+ let mut buf2 = [0; 32];
+ let mut data = Buffer::new_empty(&mut buf);
data.try_extend_from_slice(b"Hello world!").unwrap();
- let orig = data.clone();
+ let orig = data.clone_backing(&mut buf2);
encode(&mut data).unwrap();
decode(&mut data).unwrap();
- assert_eq!(orig, data);
+ assert_eq!(*orig, *data);
}
#[test]
fn basic_encode_decode() {
- let mut data: ArrayVec<u8, 8191> = ArrayVec::new();
+ let mut buf = [0; 8191];
+ let mut buf2 = [0; 8191];
+ let mut data = Buffer::new_empty(&mut buf);
for _ in 0..50 {
- data.extend(
- b"This is a test packet. jsalksjd093809324JASLD:LKD*#$)(*#@)"
- .iter()
- .cloned(),
- );
+ data.extend(b"This is a test packet. jsalksjd093809324JASLD:LKD*#$)(*#@)");
}
- let orig = data.clone();
+ let orig = data.clone_backing(&mut buf2);
encode(&mut data).unwrap();
- assert_ne!(orig, data);
+ assert_ne!(*orig, *data);
decode(&mut data).unwrap();
- assert_eq!(orig, data);
+ assert_eq!(*orig, *data);
}
#[test]
fn encode_decode_with_bit_flips() {
- let mut data: ArrayVec<u8, 8191> = ArrayVec::new();
+ let mut buf = [0; 8191];
+ let mut buf2 = [0; 8191];
+ let mut data = Buffer::new_empty(&mut buf);
+
for _ in 0..50 {
- data.extend(
- b"jsalksjd093809324JASLD:LKD*#$)(*#@) Another test packet"
- .iter()
- .cloned(),
- );
+ data.extend(b"jsalksjd093809324JASLD:LKD*#$)(*#@) Another test packet");
}
- let orig = data.clone();
+ let orig = data.clone_backing(&mut buf2);
encode(&mut data).unwrap();
- assert_ne!(orig, data);
+ assert_ne!(*orig, *data);
data[234] ^= 0x55;
data[0] ^= 0xAA;
@@ -237,6 +228,6 @@ mod tests {
decode(&mut data).unwrap();
- assert_eq!(orig, data);
+ assert_eq!(*orig, *data);
}
}
diff --git a/src/packet.rs b/src/packet.rs
index f669b1b..7565205 100644
--- a/src/packet.rs
+++ b/src/packet.rs
@@ -1,6 +1,5 @@
use core::fmt::Debug;
-use arrayvec::{ArrayVec, CapacityError};
use crc::{Crc, CRC_16_IBM_SDLC};
use crate::{
@@ -31,7 +30,7 @@ macro_rules! uniq_whisker {
return Err(EncodeError::DuplicateData);
}
- try_lock(&mut self.data, |data| {
+ try_lock(&mut self.buf, |data| {
let mut buf = [0; 256];
// safe to unwrap since we know we have enough space
let out = w.encode(&mut buf).unwrap();
@@ -67,7 +66,7 @@ macro_rules! poly_whisker {
}
pub fn [<add_ $t:lower>](&mut self, w: $t) -> Result<(), EncodeError> {
- try_lock(self.buf.as_slice_mut(), |data| {
+ try_lock(&mut self.buf, |data| {
let mut buf = [0; 256];
// safe to unwrap since we know we have enough space
let out = w.encode(&mut buf).unwrap();
@@ -148,7 +147,7 @@ impl<'a, const N: usize> Packet<'a, N> {
/// Directly after the CRC block in The Pipeline
/// Expects bytes in the `buf`
/// `buf` is used as the backing buffer for the Packet
- pub fn semi_decode(buf: Buffer<'a, N>) -> Result<Self, DecodeError> {
+ pub fn semi_decode(mut buf: Buffer<'a, N>) -> Result<Self, DecodeError> {
let crc1 = buf.pop().ok_or(DecodeError::UnexpectedEndOfInput)?;
let crc0 = buf.pop().ok_or(DecodeError::UnexpectedEndOfInput)?;
let crc_expected = u16::from_le_bytes([crc0, crc1]);
@@ -163,34 +162,34 @@ impl<'a, const N: usize> Packet<'a, N> {
/// Encodes packet for transmission on the air.
/// Includes the data length L, but does not include the preamble or sync word.
- // TODO buffer-ify this
- pub fn fully_encode(self) -> Result<ArrayVec<u8, N>, EncodeError> {
+ pub fn fully_encode(self, out: &mut Buffer<N>) -> Result<(), EncodeError> {
let mut data = self.semi_encode().map_err(|(err, _)| err)?;
whitener::whiten(&mut data);
ldpc::encode(&mut data)?;
- let mut out: ArrayVec<u8, N> = ArrayVec::new();
+
// safe to unwrap - length must be below 8191
out.try_extend_from_slice(&u16::try_from(data.len()).unwrap().to_le_bytes())
.map_err(|_| EncodeError::CatsOverflow)?;
- interleaver::interleave(&data, &mut out)?;
+ interleaver::interleave(&data, out)?;
- Ok(out)
+ Ok(())
}
/// Decodes packet that was received over the air.
/// Packet shouldn't have preamble, sync word, or data langth L.
/// Expects bytes in the `buf`
/// `buf` is used as the backing buffer for the Packet
- pub fn fully_decode(buf: Buffer<'a, N>) -> Result<Self, DecodeError> {
- let mut data = interleaver::uninterleave(buf).map_err(|_| DecodeError::Overflow)?;
- ldpc::decode(&mut data).ok_or(DecodeError::LdpcError)?;
- whitener::whiten(&mut data);
+ pub fn fully_decode(data: &[u8], buf: &'a mut [u8; N]) -> Result<Self, DecodeError> {
+ let mut buf = Buffer::new_empty(buf);
+ interleaver::uninterleave(data, &mut buf).map_err(|_| DecodeError::Overflow)?;
+ ldpc::decode(&mut buf).ok_or(DecodeError::LdpcError)?;
+ whitener::whiten(&mut buf);
- Self::semi_decode(data)
+ Self::semi_decode(buf)
}
pub fn iter(&self) -> ValidatedWhiskerIter {
- ValidatedWhiskerIter::new(&self.data)
+ ValidatedWhiskerIter::new(&self.buf)
}
uniq_whisker!(Identification);
@@ -200,7 +199,7 @@ impl<'a, const N: usize> Packet<'a, N> {
poly_whisker!(Destination);
poly_whisker!(Arbitrary);
- pub fn comment<'b>(&self, buf: &'b mut [u8]) -> Result<&'a str, CommentError> {
+ pub fn comment<'b>(&self, buf: &'b mut [u8]) -> Result<&'b str, CommentError> {
let iter = self.iter().filter_map(|w| match w {
Whisker::Comment(c) => Some(c),
_ => None,
@@ -232,7 +231,7 @@ impl<'a, const N: usize> Packet<'a, N> {
return Err(EncodeError::DuplicateData);
}
- try_lock(&mut self.data, |data| {
+ try_lock(&mut self.buf, |data| {
let mut comment = comment.as_bytes();
while comment.len() > 255 {
@@ -269,12 +268,12 @@ impl<'a, const N: usize> Packet<'a, N> {
fn clear_by_type(&mut self, whisker_type: u8, all: bool) {
let mut i = 0;
- while i < self.data.len() {
- let t = self.data[i];
- let step = usize::from(self.data[i + 1]) + 2;
+ while i < self.buf.len() {
+ let t = self.buf[i];
+ let step = usize::from(self.buf[i + 1]) + 2;
if t == whisker_type {
- self.data.drain(i..(i + step));
+ self.buf.drain(i, i + step);
if !all {
return;
@@ -289,7 +288,7 @@ impl<'a, const N: usize> Packet<'a, N> {
impl<'a, const N: usize> Debug for Packet<'a, N> {
fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
f.debug_list()
- .entries(ValidatedWhiskerIter::new(self.buf.as_slice()))
+ .entries(ValidatedWhiskerIter::new(&self.buf))
.finish()
}
}
@@ -314,7 +313,7 @@ fn try_lock<'a, const N: usize, T, E, F: Fn(&mut Buffer<'a, N>) -> Result<T, E>>
#[cfg(test)]
mod tests {
- use arrayvec::ArrayString;
+ use arrayvec::{ArrayString, ArrayVec};
use super::*;
@@ -323,7 +322,8 @@ mod tests {
let d1 = Destination::new(false, 7, "CALL1", 23).unwrap();
let d2 = Destination::new(true, 23, "CALL2", 2).unwrap();
- let mut packet: Packet<1024> = Packet::default();
+ let mut buf = [0; 1024];
+ let mut packet: Packet<1024> = Packet::new(&mut buf);
packet.add_destination(d1.clone()).unwrap();
packet.add_destination(d2.clone()).unwrap();
@@ -335,7 +335,8 @@ mod tests {
#[test]
fn route_clear() {
- let mut p: Packet<1024> = Packet::default();
+ let mut buf = [0; 1024];
+ let mut p: Packet<1024> = Packet::new(&mut buf);
p.add_identification(Identification::new(123, "call", 43).unwrap())
.unwrap();
let mut r = Route::new(8);
@@ -358,7 +359,8 @@ mod tests {
fn semi_e2e() {
let comment = "Hello world! This is a comment. It's long so that it needs to be split across more than one whisker.Hello world! This is a comment. It's long so that it needs to be split across more than one whisker.Hello world! This is a comment. It's long so that it needs to be split across more than one whisker.Hello world! This is a comment. It's long so that it needs to be split across more than one whisker.Hello world! This is a comment. It's long so that it needs to be split across more than one whisker.Hello world! This is a comment. It's long so that it needs to be split across more than one whisker.Hello world! This is a comment. It's long so that it needs to be split across more than one whisker.Hello world! This is a comment. It's long so that it needs to be split across more than one whisker.Hello world! This is a comment. It's long so that it needs to be split across more than one whisker.Hello world! This is a comment. It's long so that it needs to be split across more than one whisker.";
- let mut packet = Packet::<2048>::default();
+ let mut buf = [0; 2048];
+ let mut packet = Packet::new(&mut buf);
packet
.add_identification(Identification {
icon: 123,
@@ -396,7 +398,8 @@ mod tests {
fn full_e2e() {
let comment = "Hello world! This is a comment. It's long so that it needs to be split across more than one whisker.Hello world! This is a comment. It's long so that it needs to be split across more than one whisker.Hello world! This is a comment. It's long so that it needs to be split across more than one whisker.Hello world! This is a comment. It's long so that it needs to be split across more than one whisker.Hello world! This is a comment. It's long so that it needs to be split across more than one whisker.Hello world! This is a comment. It's long so that it needs to be split across more than one whisker.Hello world! This is a comment. It's long so that it needs to be split across more than one whisker.Hello world! This is a comment. It's long so that it needs to be split across more than one whisker.Hello world! This is a comment. It's long so that it needs to be split across more than one whisker.Hello world! This is a comment. It's long so that it needs to be split across more than one whisker.";
- let mut packet = Packet::<4096>::default();
+ let mut buf = [0; 4096];
+ let mut packet = Packet::new(&mut buf);
packet
.add_identification(Identification {
icon: 123,
@@ -414,13 +417,16 @@ mod tests {
});
assert!(matches!(res, Err(EncodeError::DuplicateData)));
- let mut fully = packet.fully_encode().unwrap();
+ let mut buf2 = [0; 4096];
+ let mut fully = Buffer::new_empty(&mut buf2);
+ packet.fully_encode(&mut fully).unwrap();
fully[40] ^= 0x55;
fully[844] ^= 0x7B;
// exclude length
- let packet2: Packet<8191> = Packet::fully_decode(&fully[2..]).unwrap();
+ let mut buf3 = [0; 8191];
+ let packet2: Packet<8191> = Packet::fully_decode(&fully[2..], &mut buf3).unwrap();
assert_eq!(
Identification {
icon: 123,
@@ -487,7 +493,8 @@ mod tests {
118, 118, 118, 118, 118, 118, 118, 0, 0, 0, 0, 96, 96,
];
- let _ = Packet::<1024>::fully_decode(&data);
+ let mut buf = [0; 1024];
+ let _ = Packet::<1024>::fully_decode(&data, &mut buf);
}
#[test]
@@ -535,13 +542,15 @@ mod tests {
)
.unwrap();
- let _ = Packet::<1024>::semi_decode(data);
+ let mut buf = [0; 1024];
+ let _ = Packet::<1024>::fully_decode(&data, &mut buf);
}
#[test]
fn decode_fuzz_tests() {
- let data = ArrayVec::try_from(&[4, 0, 0, 0][..]).unwrap();
+ let data = [4, 0, 0, 0];
- let _ = Packet::<1024>::decode(data);
+ let mut buf = [0; 1024];
+ let _ = Packet::<1024>::fully_decode(&data, &mut buf);
}
}
diff --git a/src/whitener.rs b/src/whitener.rs
index 53d846d..79d21d9 100644
--- a/src/whitener.rs
+++ b/src/whitener.rs
@@ -14,9 +14,9 @@ mod tests {
#[test]
fn basic() {
- let mut data: ArrayVec<u8, 512> =
- ArrayVec::try_from(&b"Hello world! The quick brown fox jumped over the lazy dog"[..])
- .unwrap();
+ let mut data = [0; 64];
+ data[0..57]
+ .clone_from_slice(&b"Hello world! The quick brown fox jumped over the lazy dog"[..]);
let orig = data.clone();
whiten(&mut data);
--
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