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Add encode_buff, small integer/bytes extend perf improvements
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@Nicceboy
Nicceboy committed Nov 23, 2024
1 parent 3094ede commit 0f28bf4
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Showing 3 changed files with 62 additions and 31 deletions.
10 changes: 6 additions & 4 deletions src/coer.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -20,18 +20,21 @@ pub fn decode<T: crate::Decode>(input: &[u8]) -> Result<T, DecodeError> {
/// Returns `EncodeError` if `value` cannot be encoded as COER, usually meaning that constraints
/// are not met.
pub fn encode<T: crate::Encode>(value: &T) -> Result<alloc::vec::Vec<u8>, EncodeError> {
// let mut enc = Encoder::<0>::new(enc::EncoderOptions::coer(), core::mem::size_of::<T>());
let mut buffer = alloc::vec::Vec::with_capacity(core::mem::size_of::<T>());
let mut enc = Encoder::<0>::from_buffer(enc::EncoderOptions::coer(), &mut buffer);
value.encode(&mut enc)?;
Ok(enc.output())
}
/// Variant of `encode` that writes to a pre-allocated buffer.
/// Attempts to encode `value` of type `T` to COER.
/// Variant of `encode` that writes to a provided existing `buffer``.
///
/// # Errors
/// Returns `EncodeError` if `value` cannot be encoded as COER, usually meaning that constraints
/// are not met.
pub fn encode_buf<T: crate::Encode>(
value: &T,
buffer: &mut alloc::vec::Vec<u8>,
) -> Result<(), EncodeError> {
// let mut enc = Encoder::<0>::new(enc::EncoderOptions::coer(), core::mem::size_of::<T>());
let mut enc = Encoder::<0>::from_buffer(enc::EncoderOptions::coer(), buffer);
value.encode(&mut enc)?;
Ok(())
Expand Down Expand Up @@ -60,7 +63,6 @@ pub fn encode_with_constraints<T: crate::Encode>(
constraints: Constraints,
value: &T,
) -> Result<alloc::vec::Vec<u8>, EncodeError> {
// let mut enc = Encoder::<0>::new(enc::EncoderOptions::coer(), core::mem::size_of::<T>());
let mut buffer = alloc::vec::Vec::with_capacity(core::mem::size_of::<T>());
let mut enc = Encoder::<0>::from_buffer(enc::EncoderOptions::coer(), &mut buffer);
value.encode_with_constraints(&mut enc, constraints)?;
Expand Down
16 changes: 16 additions & 0 deletions src/oer.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -30,6 +30,22 @@ pub fn encode<T: crate::Encode>(value: &T) -> Result<alloc::vec::Vec<u8>, Encode
value.encode(&mut enc)?;
Ok(enc.output())
}

/// Attempts to encode `value` of type `T` to COER.
/// Variant of `encode` that writes to a provided existing `buffer``.
///
/// # Errors
/// Returns `EncodeError` if `value` cannot be encoded as COER, usually meaning that constraints
/// are not met.
pub fn encode_buf<T: crate::Encode>(
value: &T,
buffer: &mut alloc::vec::Vec<u8>,
) -> Result<(), EncodeError> {
let mut enc = Encoder::<0>::from_buffer(enc::EncoderOptions::coer(), buffer);
value.encode(&mut enc)?;
Ok(())
}

/// Attempts to decode `T` from `input` using OER with constraints.
///
/// # Errors
Expand Down
67 changes: 40 additions & 27 deletions src/oer/enc.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -2,6 +2,7 @@
use alloc::vec::Vec;
use bitvec::prelude::*;
use nom::AsBytes;
use num_traits::ToPrimitive;

use crate::{
Expand Down Expand Up @@ -91,7 +92,7 @@ pub struct Encoder<'buffer, const RCL: usize = 0, const ECL: usize = 0> {
// which alternative of the choice type is the chosen alternative (see 20.1).
impl<'buffer, const RCL: usize, const ECL: usize> Encoder<'buffer, RCL, ECL> {
#[must_use]
/// Constructs a new encoder from options that borrows the buffer from output.
/// Constructs a new encoder from options and existing `buffer`.
pub fn from_buffer(options: EncoderOptions, output: &'buffer mut Vec<u8>) -> Self {
Self {
options,
Expand Down Expand Up @@ -263,8 +264,8 @@ impl<'buffer, const RCL: usize, const ECL: usize> Encoder<'buffer, RCL, ECL> {
// We must swap the first bit to show long form
// It is always zero by default with u8 type when value being < 128
length |= 0b_1000_0000;
self.output.extend(&length.to_be_bytes());
self.output.extend(&bytes.as_ref()[..needed]);
self.output.extend_from_slice(&length.to_be_bytes());
self.output.extend_from_slice(&bytes.as_ref()[..needed]);
Ok(())
}
/// Encode the length of the value to output.
Expand All @@ -275,7 +276,7 @@ impl<'buffer, const RCL: usize, const ECL: usize> Encoder<'buffer, RCL, ECL> {
let (bytes, needed) = length.to_unsigned_bytes_be();
if length < 128 {
// First bit should be always zero when below 128: ITU-T X.696 8.6.4
self.output.extend(&bytes.as_ref()[..needed]);
self.output.extend_from_slice(&bytes.as_ref()[..needed]);
return Ok(());
}
let mut length_of_length = u8::try_from(needed).map_err(|err| {
Expand All @@ -293,8 +294,9 @@ impl<'buffer, const RCL: usize, const ECL: usize> Encoder<'buffer, RCL, ECL> {
// We must swap the first bit to show long form
// It is always zero by default with u8 type when value being < 128
length_of_length |= 0b_1000_0000;
self.output.extend(&length_of_length.to_be_bytes());
self.output.extend(&bytes.as_ref()[..needed]);
self.output
.extend_from_slice(&length_of_length.to_be_bytes());
self.output.extend_from_slice(&bytes.as_ref()[..needed]);
Ok(())
}
/// Encode integer `value_to_enc` with length determinant
Expand All @@ -308,11 +310,11 @@ impl<'buffer, const RCL: usize, const ECL: usize> Encoder<'buffer, RCL, ECL> {
if signed {
let (bytes, needed) = value_to_enc.to_signed_bytes_be();
self.encode_length(needed)?;
self.output.extend(&bytes.as_ref()[..needed]);
self.output.extend_from_slice(&bytes.as_ref()[..needed]);
} else {
let (bytes, needed) = value_to_enc.to_unsigned_bytes_be();
self.encode_length(needed)?;
self.output.extend(&bytes.as_ref()[..needed]);
self.output.extend_from_slice(&bytes.as_ref()[..needed]);
};
Ok(())
}
Expand Down Expand Up @@ -386,14 +388,17 @@ impl<'buffer, const RCL: usize, const ECL: usize> Encoder<'buffer, RCL, ECL> {
};
match octets.cmp(&needed) {
Ordering::Greater => {
if signed && value.is_negative() {
// 2's complement
self.output
.extend(core::iter::repeat(0xff).take(octets - needed));
const MAX_OCTETS: usize = 8;
let mut padded_bytes = [0u8; MAX_OCTETS];
let padding_value = if signed && value.is_negative() {
0xff
} else {
self.output
.extend(core::iter::repeat(0x00).take(octets - needed));
}
0x00
};
padded_bytes.fill(padding_value);
padded_bytes[(octets - needed)..octets].copy_from_slice(&bytes[..needed]);
self.output.extend_from_slice(&padded_bytes[..octets]);
return Ok(());
}
Ordering::Less => {
return Err(EncodeError::from_kind(
Expand All @@ -407,7 +412,7 @@ impl<'buffer, const RCL: usize, const ECL: usize> Encoder<'buffer, RCL, ECL> {
// As is
Ordering::Equal => {}
};
self.output.extend(&bytes[..needed]);
self.output.extend_from_slice(&bytes[..needed]);
Ok(())
}
fn check_fixed_size_constraint(
Expand Down Expand Up @@ -507,7 +512,7 @@ impl<'buffer, const RCL: usize, const ECL: usize> Encoder<'buffer, RCL, ECL> {
let missing_bits: u8 = if EC > 0 { (8 - (EC & 7) as u8) & 7 } else { 0 };
debug_assert!((EC + 8 + missing_bits as usize) % 8 == 0);
self.encode_length((8 + EC + missing_bits as usize) / 8)?;
self.output.extend(missing_bits.to_be_bytes());
self.output.extend_from_slice(&missing_bits.to_be_bytes());
for (i, bit) in self.extension_bitfield.1.iter().enumerate() {
extension_bitmap_buffer.set(i, *bit);
}
Expand Down Expand Up @@ -551,7 +556,7 @@ impl<'buffer, const RFC: usize, const EFC: usize> crate::Encoder<'buffer>
/// In Basic-OER, any non-zero octet value represents true, but we support only canonical encoding.
fn encode_bool(&mut self, tag: Tag, value: bool) -> Result<Self::Ok, Self::Error> {
self.output
.extend(if value { &[0xffu8] } else { &[0x00u8] });
.extend_from_slice(if value { &[0xffu8] } else { &[0x00u8] });
self.extend(tag)
}

Expand Down Expand Up @@ -585,7 +590,8 @@ impl<'buffer, const RFC: usize, const EFC: usize> crate::Encoder<'buffer>
} else {
bit_string_encoding.extend(value);
}
self.output.extend(bit_string_encoding.as_raw_slice());
self.output
.extend_from_slice(bit_string_encoding.as_raw_slice());
} else {
return Err(EncodeError::size_constraint_not_satisfied(
value.len(),
Expand All @@ -601,7 +607,7 @@ impl<'buffer, const RFC: usize, const EFC: usize> crate::Encoder<'buffer>
// If the BitString is empty, length is one and initial octet is zero
if value.is_empty() {
self.encode_length(1)?;
self.output.extend(&[0x00u8]);
self.output.extend_from_slice(&[0x00u8]);
} else {
// TODO 22.7 X.680, NamedBitString and COER
// if self.options.encoding_rules.is_coer()
Expand All @@ -622,7 +628,8 @@ impl<'buffer, const RFC: usize, const EFC: usize> crate::Encoder<'buffer>
bit_string_encoding.extend(value);
bit_string_encoding.extend(trailing);
self.encode_length(bit_string_encoding.len() / 8)?;
self.output.extend(bit_string_encoding.as_raw_slice());
self.output
.extend_from_slice(bit_string_encoding.as_raw_slice());
}
self.extend(tag)?;
Ok(())
Expand Down Expand Up @@ -682,11 +689,11 @@ impl<'buffer, const RFC: usize, const EFC: usize> crate::Encoder<'buffer>
value: &[u8],
) -> Result<Self::Ok, Self::Error> {
if self.check_fixed_size_constraint(value.len(), &constraints)? {
self.output.extend(value);
self.output.extend_from_slice(value);
} else {
// Use length determinant on other cases
self.encode_length(value.len())?;
self.output.extend(value);
self.output.extend_from_slice(value);
}
self.extend(tag)?;
Ok(())
Expand Down Expand Up @@ -871,11 +878,16 @@ impl<'buffer, const RFC: usize, const EFC: usize> crate::Encoder<'buffer>
C: Constructed<RL, EL>,
F: for<'b> FnOnce(&'b mut Self::AnyEncoder<'this, RL, EL>) -> Result<(), Self::Error>,
{
self.options.set_encoding = true;
let mut encoder = Encoder::<RL, EL>::from_buffer(self.options, self.output);
let mut options = self.options;
options.set_encoding = true;
let mut encoder = Encoder::<RL, EL>::from_buffer(options, self.output);
encoder.number_optional_default_fields = C::FIELDS.number_of_optional_and_default_fields();
encoder_scope(&mut encoder)?;
encoder.encode_constructed::<RL, EL, C>(tag, 0, None)?;
if self.options.set_encoding {
encoder.encode_constructed::<RL, EL, C>(tag, 0, Some(&mut self.set_output))?;
} else {
encoder.encode_constructed::<RL, EL, C>(tag, 0, None)?;
}
encoder.collect_set();
Ok(())
}
Expand Down Expand Up @@ -927,7 +939,8 @@ impl<'buffer, const RFC: usize, const EFC: usize> crate::Encoder<'buffer>
let mut tag_buffer: BitArray<[u8; core::mem::size_of::<Tag>() + 1], Msb0> =
BitArray::default();
let needed = self.encode_tag(tag, tag_buffer.as_mut_bitslice());
self.output.extend(tag_buffer[..needed].domain());
self.output
.extend_from_slice(&tag_buffer.as_raw_slice()[..(needed / 8)]);
if is_root_extension {
self.output.append(&mut output);
} else {
Expand Down

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