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| #[inline] | |
| fn is_hex_prefixed_matches(s: &str) -> bool { | |
| matches!(s.as_bytes(), [b'0',b'x', ..] | [b'0',b'X', ..]) | |
| } | |
| #[inline] | |
| fn is_hex_prefixed_unsafe(s: &str) -> bool { | |
| let x = | |
| unsafe { ((*s.as_ptr() as u16) << 8) | (*s.as_ptr().add((s.len() > 1) as usize)) as u16 }; | |
| (x ^ 0x3078) & (x ^ 0x3050) == 0 | |
| } | |
| #[inline] | |
| pub fn is_hex_prefixed_checked(s: &str) -> bool { | |
| let bytes = s.as_bytes(); | |
| if bytes.len() >= 2 { | |
| let array = unsafe{ *(bytes.as_ptr() as *const [u8;2]) }; | |
| matches!(&array, b"0x" | b"0X") | |
| }else{ | |
| false | |
| } | |
| } | |
| use criterion::{black_box, criterion_group, criterion_main, Criterion}; | |
| use rand::Rng; | |
| use rand::rngs::ThreadRng; | |
| pub fn criterion_benchmark(c: &mut Criterion) { | |
| let mut rng = rand::thread_rng(); | |
| const CHARSET: &[u8] = b"ABCDEFGHIJKLMNOPQRSTUVWXYZ\ | |
| abcdefghijklmnopqrstuvwxyz\ | |
| 0123456789)(*&^%$#@!~"; | |
| const STR_LEN: usize = 8; | |
| fn rand_str(rng: &mut ThreadRng) -> String { | |
| (0..STR_LEN).map(|_| { | |
| let idx = rng.gen_range(0, CHARSET.len()); | |
| CHARSET[idx] as char | |
| }) | |
| .collect() | |
| } | |
| let rand_strs: Vec<String> = (0..1000000).map(|_| rand_str(&mut rng)).collect(); | |
| let mut iter_1 = rand_strs.iter().cycle(); | |
| let mut iter_2 = rand_strs.iter().cycle(); | |
| let mut iter_3 = rand_strs.iter().cycle(); | |
| c.bench_function("is_hex_prefixed_matches", |b| b.iter(|| is_hex_prefixed_matches(black_box(iter_1.next().unwrap())))); | |
| c.bench_function("is_hex_prefixed_unsafe", |b| b.iter(|| is_hex_prefixed_unsafe(black_box(iter_2.next().unwrap())))); | |
| c.bench_function("is_hex_prefixed_checked", |b| b.iter(|| is_hex_prefixed_checked(black_box(iter_3.next().unwrap())))); | |
| } | |
| criterion_group!(benches, criterion_benchmark); | |
| criterion_main!(benches); |
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