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* Replace our base64 implementation with one based on `base64-simd` * Bump Rust MSRV to 1.62.1 * Unmark base64-related tests as failing * Use `usize` for `base64::encoded_length` * Run Rust 1.62.1 on CI * Don't use external `base64_simd::Error` type in public interface * Add initial criterion bench setup for base64 * Compare `base64_simd::encode` vs Smithy's `encode` * Use string length for `BenchmarkId` * Compare `base64_simd::decode` vs Smithy's `decode` * Compare `base64_simd::encoded_length` vs Smithy's `encoded_length`
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/* | ||
* Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved. | ||
* SPDX-License-Identifier: Apache-2.0 | ||
*/ | ||
|
||
use criterion::{criterion_group, criterion_main, BenchmarkId, Criterion}; | ||
use rand; | ||
use rand::distributions::{Alphanumeric, DistString}; | ||
|
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/// Generates a random string of a given length | ||
fn random_string(len: usize) -> String { | ||
Alphanumeric.sample_string(&mut rand::thread_rng(), len) | ||
} | ||
|
||
const INPUT_SIZES: [usize; 4] = [1, 10, 1_000, 100_000]; | ||
|
||
fn bench_encodes(c: &mut Criterion) { | ||
let mut group = c.benchmark_group("Encode"); | ||
|
||
for length in INPUT_SIZES { | ||
let input = &random_string(length); | ||
|
||
group.bench_with_input( | ||
BenchmarkId::new("handrolled_base64", length), | ||
input, | ||
|b, i| b.iter(|| handrolled_base64::encode(i)), | ||
); | ||
group.bench_with_input(BenchmarkId::new("base64_simd", length), input, |b, i| { | ||
b.iter(|| aws_smithy_types::base64::encode(i)) | ||
}); | ||
} | ||
group.finish() | ||
} | ||
|
||
fn bench_decodes(c: &mut Criterion) { | ||
let mut group = c.benchmark_group("Decode"); | ||
|
||
for length in INPUT_SIZES { | ||
let string = &random_string(length); | ||
let encoded = &aws_smithy_types::base64::encode(string); | ||
|
||
group.bench_with_input( | ||
BenchmarkId::new("handrolled_base64", length), | ||
encoded, | ||
|b, i| b.iter(|| handrolled_base64::decode(i).unwrap()), | ||
); | ||
group.bench_with_input(BenchmarkId::new("base64_simd", length), encoded, |b, i| { | ||
b.iter(|| aws_smithy_types::base64::decode(i).unwrap()) | ||
}); | ||
} | ||
group.finish() | ||
} | ||
|
||
fn bench_encoded_lengths(c: &mut Criterion) { | ||
let mut group = c.benchmark_group("Decoded length"); | ||
|
||
for length in INPUT_SIZES { | ||
group.bench_with_input( | ||
BenchmarkId::new("handrolled_base64", length), | ||
&length, | ||
|b, &i| b.iter(|| handrolled_base64::encoded_length(i as u64)), | ||
); | ||
group.bench_with_input(BenchmarkId::new("base64_simd", length), &length, |b, &i| { | ||
b.iter(|| aws_smithy_types::base64::encoded_length(i)) | ||
}); | ||
} | ||
group.finish() | ||
} | ||
|
||
criterion_group!(benches, bench_encodes, bench_decodes, bench_encoded_lengths); | ||
criterion_main!(benches); | ||
|
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mod handrolled_base64 { | ||
/* | ||
* Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved. | ||
* SPDX-License-Identifier: Apache-2.0 | ||
*/ | ||
|
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//! A correct, small, but not especially fast base64 implementation | ||
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use std::error::Error; | ||
use std::fmt; | ||
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const BASE64_ENCODE_TABLE: &[u8; 64] = | ||
b"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"; | ||
|
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const BASE64_DECODE_TABLE: &[Option<u8>; 256] = &decode_table(); | ||
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const PADDING_SENTINEL: u8 = 0xFF; | ||
|
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const fn encode_table_index_of(i: usize) -> Option<u8> { | ||
let mut index = 0; | ||
// inline const index-of implementation | ||
while index < BASE64_ENCODE_TABLE.len() { | ||
if BASE64_ENCODE_TABLE[index] as usize == i { | ||
return Some(index as u8); | ||
} | ||
index += 1; | ||
} | ||
None | ||
} | ||
|
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/// Build a decode table mapping `char as u8` to base64 bit sequences | ||
const fn decode_table() -> [Option<u8>; 256] { | ||
let mut output = [None; 256]; | ||
let mut i = 0; | ||
while i < 256 { | ||
if i == 61 { | ||
output[i] = Some(PADDING_SENTINEL); | ||
} else { | ||
output[i] = encode_table_index_of(i); | ||
} | ||
i += 1; | ||
} | ||
output | ||
} | ||
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/// Encode `input` into base64 using the standard base64 alphabet | ||
pub fn encode<T: AsRef<[u8]>>(input: T) -> String { | ||
encode_inner(input.as_ref()) | ||
} | ||
|
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/// encode_inner defined to reduce monomorphisation cost | ||
fn encode_inner(inp: &[u8]) -> String { | ||
// Base 64 encodes groups of 6 bits into characters—this means that each | ||
// 3 byte group (24 bits) is encoded into 4 base64 characters. | ||
let char_ct = ((inp.len() + 2) / 3) * 4; | ||
let mut output = String::with_capacity(char_ct); | ||
for chunk in inp.chunks(3) { | ||
let mut block: i32 = 0; | ||
// Write the chunks into the beginning of a 32 bit int | ||
for (idx, chunk) in chunk.iter().enumerate() { | ||
block |= (*chunk as i32) << ((3 - idx) * 8); | ||
} | ||
let num_sextets = ((chunk.len() * 8) + 5) / 6; | ||
for idx in 0..num_sextets { | ||
let slice = block >> (26 - (6 * idx)); | ||
let idx = (slice as u8) & 0b0011_1111; | ||
output.push(BASE64_ENCODE_TABLE[idx as usize] as char); | ||
} | ||
for _ in 0..(4 - num_sextets) { | ||
output.push('='); | ||
} | ||
} | ||
// be sure we calculated the size right | ||
debug_assert_eq!(output.capacity(), char_ct); | ||
output | ||
} | ||
|
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/// Decode `input` from base64 using the standard base64 alphabet | ||
/// | ||
/// If input is not a valid base64 encoded string, this function will return `DecodeError`. | ||
pub fn decode<T: AsRef<str>>(input: T) -> Result<Vec<u8>, DecodeError> { | ||
decode_inner(input.as_ref()) | ||
} | ||
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/// Failure to decode a base64 value. | ||
#[derive(Debug, Clone, Eq, PartialEq)] | ||
#[non_exhaustive] | ||
pub enum DecodeError { | ||
/// Encountered an invalid byte. | ||
InvalidByte, | ||
/// Encountered an invalid base64 padding value. | ||
InvalidPadding, | ||
/// Input wasn't long enough to be a valid base64 value. | ||
InvalidLength, | ||
} | ||
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impl Error for DecodeError {} | ||
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impl fmt::Display for DecodeError { | ||
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { | ||
use DecodeError::*; | ||
match self { | ||
InvalidByte => write!(f, "invalid byte"), | ||
InvalidPadding => write!(f, "invalid padding"), | ||
InvalidLength => write!(f, "invalid length"), | ||
} | ||
} | ||
} | ||
|
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fn decode_inner(inp: &str) -> Result<Vec<u8>, DecodeError> { | ||
// one base64 character is only 6 bits so it can't produce valid data. | ||
if inp.len() == 1 { | ||
return Err(DecodeError::InvalidLength); | ||
} | ||
|
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// when there's padding, we might slightly over allocate but it significantly simplifies | ||
// the code to just ignore it. | ||
let mut ret = Vec::with_capacity((inp.len() + 3) / 4 * 3); | ||
|
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// 4 base-64 characters = 3 bytes | ||
// 1. Break the input into 4 character segments | ||
// 2. Write those segments into an i32 | ||
// 3. Read u8s back out of the i32 | ||
let chunks = inp.as_bytes().chunks(4); | ||
let mut padding = 0; | ||
for chunk in chunks { | ||
// padding should only be set on the last input | ||
if padding != 0 { | ||
return Err(DecodeError::InvalidPadding); | ||
} | ||
let mut block = 0_i32; | ||
for (idx, chunk) in chunk.iter().enumerate() { | ||
let bits = BASE64_DECODE_TABLE[*chunk as usize].ok_or(DecodeError::InvalidByte)?; | ||
if bits == 0xFF { | ||
padding += 1; | ||
} else if padding > 0 { | ||
// Once you've started padding, you can't stop. | ||
return Err(DecodeError::InvalidPadding); | ||
} | ||
block |= (bits as i32) << (18 - (idx * 6)); | ||
} | ||
// if we got a short slice, its because of implied padding | ||
let missing_chars = 4 - chunk.len(); | ||
for i in (padding + missing_chars..3).rev() { | ||
let byte = ((block >> (i * 8)) & 0xFF) as u8; | ||
ret.push(byte) | ||
} | ||
} | ||
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// The code is much simpler if we _slightly_ over allocate in certain cases | ||
debug_assert!(ret.capacity() - ret.len() < 4); | ||
Ok(ret) | ||
} | ||
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/// Given the length of some data in bytes, return how many bytes it would take to base64 encode | ||
/// that data. | ||
pub fn encoded_length(length: u64) -> u64 { | ||
(length + 2) / 3 * 4 | ||
} | ||
} |
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