This crate provides a fast conversion of byte arrays to hexadecimal strings, both at compile time, and at run time.
It aims to be a drop-in replacement for the hex crate, as well as extending
the API with const-eval, a const-generics formatting buffer, similar
to itoa's, and more.
Version requirement: rustc 1.64
This crate's performance is comparable with faster-hex, but the latter only
provides specialized implementations for x86/x86-64.
This crate is 10 to 50 times faster than hex in encoding and decoding, and
100 times faster than libstd in formatting.
The following benchmarks were ran on an AMD Ryzen 9 7950X, compiled with
1.78.0-nightly (a4472498d 2024-02-15) on x86_64-unknown-linux-gnu.
You can run these benchmarks with cargo bench --features std on a nightly
compiler.
test decode::const_hex::bench1_32b ... bench: 14 ns/iter ( /- 0)
test decode::const_hex::bench2_256b ... bench: 37 ns/iter ( /- 4)
test decode::const_hex::bench3_2k ... bench: 226 ns/iter ( /- 7)
test decode::const_hex::bench4_16k ... bench: 1,636 ns/iter ( /- 13)
test decode::const_hex::bench5_128k ... bench: 12,644 ns/iter ( /- 84)
test decode::const_hex::bench6_1m ... bench: 102,836 ns/iter ( /- 3,236)
test decode::faster_hex::bench1_32b ... bench: 15 ns/iter ( /- 0)
test decode::faster_hex::bench2_256b ... bench: 50 ns/iter ( /- 1)
test decode::faster_hex::bench3_2k ... bench: 244 ns/iter ( /- 4)
test decode::faster_hex::bench4_16k ... bench: 1,782 ns/iter ( /- 31)
test decode::faster_hex::bench5_128k ... bench: 13,745 ns/iter ( /- 66)
test decode::faster_hex::bench6_1m ... bench: 115,126 ns/iter ( /- 1,544)
test decode::hex::bench1_32b ... bench: 101 ns/iter ( /- 6)
test decode::hex::bench2_256b ... bench: 701 ns/iter ( /- 12)
test decode::hex::bench3_2k ... bench: 5,287 ns/iter ( /- 97)
test decode::hex::bench4_16k ... bench: 41,743 ns/iter ( /- 1,420)
test decode::hex::bench5_128k ... bench: 782,327 ns/iter ( /- 18,876)
test decode::hex::bench6_1m ... bench: 6,283,181 ns/iter ( /- 88,813)
test decode_to_slice::const_hex::bench1_32b ... bench: 5 ns/iter ( /- 0)
test decode_to_slice::const_hex::bench2_256b ... bench: 25 ns/iter ( /- 0)
test decode_to_slice::const_hex::bench3_2k ... bench: 201 ns/iter ( /- 3)
test decode_to_slice::const_hex::bench4_16k ... bench: 1,600 ns/iter ( /- 17)
test decode_to_slice::const_hex::bench5_128k ... bench: 12,732 ns/iter ( /- 119)
test decode_to_slice::const_hex::bench6_1m ... bench: 103,414 ns/iter ( /- 2,402)
test decode_to_slice::faster_hex::bench1_32b ... bench: 6 ns/iter ( /- 0)
test decode_to_slice::faster_hex::bench2_256b ... bench: 28 ns/iter ( /- 0)
test decode_to_slice::faster_hex::bench3_2k ... bench: 206 ns/iter ( /- 3)
test decode_to_slice::faster_hex::bench4_16k ... bench: 1,640 ns/iter ( /- 13)
test decode_to_slice::faster_hex::bench5_128k ... bench: 13,065 ns/iter ( /- 92)
test decode_to_slice::faster_hex::bench6_1m ... bench: 105,963 ns/iter ( /- 2,831)
test decode_to_slice::hex::bench1_32b ... bench: 37 ns/iter ( /- 0)
test decode_to_slice::hex::bench2_256b ... bench: 298 ns/iter ( /- 6)
test decode_to_slice::hex::bench3_2k ... bench: 2,552 ns/iter ( /- 27)
test decode_to_slice::hex::bench4_16k ... bench: 20,335 ns/iter ( /- 581)
test decode_to_slice::hex::bench5_128k ... bench: 611,494 ns/iter ( /- 11,531)
test decode_to_slice::hex::bench6_1m ... bench: 4,941,477 ns/iter ( /- 180,172)
test encode::const_hex::bench1_32b ... bench: 10 ns/iter ( /- 0)
test encode::const_hex::bench2_256b ... bench: 27 ns/iter ( /- 0)
test encode::const_hex::bench3_2k ... bench: 97 ns/iter ( /- 0)
test encode::const_hex::bench4_16k ... bench: 644 ns/iter ( /- 8)
test encode::const_hex::bench5_128k ... bench: 4,967 ns/iter ( /- 52)
test encode::const_hex::bench6_1m ... bench: 45,424 ns/iter ( /- 1,922)
test encode::faster_hex::bench1_32b ... bench: 17 ns/iter ( /- 0)
test encode::faster_hex::bench2_256b ... bench: 36 ns/iter ( /- 0)
test encode::faster_hex::bench3_2k ... bench: 95 ns/iter ( /- 1)
test encode::faster_hex::bench4_16k ... bench: 597 ns/iter ( /- 10)
test encode::faster_hex::bench5_128k ... bench: 4,538 ns/iter ( /- 180)
test encode::faster_hex::bench6_1m ... bench: 41,513 ns/iter ( /- 779)
test encode::hex::bench1_32b ... bench: 97 ns/iter ( /- 0)
test encode::hex::bench2_256b ... bench: 694 ns/iter ( /- 4)
test encode::hex::bench3_2k ... bench: 5,476 ns/iter ( /- 28)
test encode::hex::bench4_16k ... bench: 43,617 ns/iter ( /- 215)
test encode::hex::bench5_128k ... bench: 348,646 ns/iter ( /- 1,155)
test encode::hex::bench6_1m ... bench: 2,895,775 ns/iter ( /- 95,699)
test encode_to_slice::const_hex::bench1_32b ... bench: 1 ns/iter ( /- 0)
test encode_to_slice::const_hex::bench2_256b ... bench: 6 ns/iter ( /- 0)
test encode_to_slice::const_hex::bench3_2k ... bench: 59 ns/iter ( /- 0)
test encode_to_slice::const_hex::bench4_16k ... bench: 438 ns/iter ( /- 2)
test encode_to_slice::const_hex::bench5_128k ... bench: 3,414 ns/iter ( /- 10)
test encode_to_slice::const_hex::bench6_1m ... bench: 28,947 ns/iter ( /- 546)
test encode_to_slice::faster_hex::bench1_32b ... bench: 4 ns/iter ( /- 0)
test encode_to_slice::faster_hex::bench2_256b ... bench: 7 ns/iter ( /- 0)
test encode_to_slice::faster_hex::bench3_2k ... bench: 63 ns/iter ( /- 0)
test encode_to_slice::faster_hex::bench4_16k ... bench: 390 ns/iter ( /- 5)
test encode_to_slice::faster_hex::bench5_128k ... bench: 3,012 ns/iter ( /- 22)
test encode_to_slice::faster_hex::bench6_1m ... bench: 26,138 ns/iter ( /- 596)
test encode_to_slice::hex::bench1_32b ... bench: 11 ns/iter ( /- 0)
test encode_to_slice::hex::bench2_256b ... bench: 116 ns/iter ( /- 0)
test encode_to_slice::hex::bench3_2k ... bench: 971 ns/iter ( /- 6)
test encode_to_slice::hex::bench4_16k ... bench: 7,821 ns/iter ( /- 48)
test encode_to_slice::hex::bench5_128k ... bench: 61,907 ns/iter ( /- 377)
test encode_to_slice::hex::bench6_1m ... bench: 499,203 ns/iter ( /- 3,771)
test format::const_hex::bench1_32b ... bench: 10 ns/iter ( /- 1)
test format::const_hex::bench2_256b ... bench: 18 ns/iter ( /- 0)
test format::const_hex::bench3_2k ... bench: 134 ns/iter ( /- 2)
test format::const_hex::bench4_16k ... bench: 1,151 ns/iter ( /- 5)
test format::const_hex::bench5_128k ... bench: 9,298 ns/iter ( /- 83)
test format::const_hex::bench6_1m ... bench: 83,611 ns/iter ( /- 1,530)
test format::std::bench1_32b ... bench: 359 ns/iter ( /- 6)
test format::std::bench2_256b ... bench: 2,773 ns/iter ( /- 44)
test format::std::bench3_2k ... bench: 22,620 ns/iter ( /- 213)
test format::std::bench4_16k ... bench: 183,197 ns/iter ( /- 1,512)
test format::std::bench5_128k ... bench: 1,481,851 ns/iter ( /- 9,791)
test format::std::bench6_1m ... bench: 11,947,054 ns/iter ( /- 132,579)
hexfor the initial encoding/decoding implementationsfaster-hexfor thex86/x86-64check and decode implementations- dtolnay/itoa for the initial crate/library API layout
Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in these crates by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.