# lowercase-hex
[](https://github.com/andunieee/lowercase-hex)
[](https://crates.io/crates/lowercase-hex)
[](https://docs.rs/lowercase-hex)
[](https://github.com/andunieee/lowercase-hex/actions?query=branch%3Amaster)
This crate provides a fast conversion of byte arrays to **lowercase** hexadecimal strings,
both at compile time, and at run time.
This is a fork of https://github.com/danipopes/const-hex that enforces strict lowercase.
_Version requirement: rustc 1.64+_
## Performance
This crate offers performance comparable to [`faster-hex`] on `x86`/`x86-64`
architectures but outperforms it on other platforms, as [`faster-hex`] is
only optimized 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
`1.83.0-nightly (9ff5fc4ff 2024-10-03)` on `x86_64-unknown-linux-gnu`.
You can run these benchmarks with `cargo bench --features std` on a nightly
compiler.
```log
test check::faster_hex::bench1_32b ... bench: 6.86 ns/iter (+/- 0.11)
test check::faster_hex::bench2_256b ... bench: 41.83 ns/iter (+/- 0.39)
test check::faster_hex::bench3_2k ... bench: 276.98 ns/iter (+/- 4.30)
test check::faster_hex::bench4_16k ... bench: 2,165.20 ns/iter (+/- 31.02)
test check::faster_hex::bench5_128k ... bench: 17,309.93 ns/iter (+/- 379.44)
test check::faster_hex::bench6_1m ... bench: 142,285.03 ns/iter (+/- 5,249.29)
test check::lowercase_hex::bench1_32b ... bench: 5.82 ns/iter (+/- 0.18)
test check::lowercase_hex::bench2_256b ... bench: 29.98 ns/iter (+/- 1.17)
test check::lowercase_hex::bench3_2k ... bench: 232.49 ns/iter (+/- 3.76)
test check::lowercase_hex::bench4_16k ... bench: 1,809.51 ns/iter (+/- 19.41)
test check::lowercase_hex::bench5_128k ... bench: 14,478.82 ns/iter (+/- 186.05)
test check::lowercase_hex::bench6_1m ... bench: 118,342.35 ns/iter (+/- 1,806.59)
test check::naive::bench1_32b ... bench: 45.06 ns/iter (+/- 3.02)
test check::naive::bench2_256b ... bench: 512.15 ns/iter (+/- 3.01)
test check::naive::bench3_2k ... bench: 5,073.88 ns/iter (+/- 37.76)
test check::naive::bench4_16k ... bench: 88,054.18 ns/iter (+/- 858.42)
test check::naive::bench5_128k ... bench: 832,259.43 ns/iter (+/- 3,408.40)
test check::naive::bench6_1m ... bench: 6,781,407.55 ns/iter (+/- 73,030.65)
test decode::faster_hex::bench1_32b ... bench: 27.74 ns/iter (+/- 0.37)
test decode::faster_hex::bench2_256b ... bench: 101.41 ns/iter (+/- 3.30)
test decode::faster_hex::bench3_2k ... bench: 703.92 ns/iter (+/- 9.18)
test decode::faster_hex::bench4_16k ... bench: 5,128.69 ns/iter (+/- 63.89)
test decode::faster_hex::bench5_128k ... bench: 40,764.42 ns/iter (+/- 709.74)
test decode::faster_hex::bench6_1m ... bench: 360,419.77 ns/iter (+/- 10,452.05)
test decode::hex::bench1_32b ... bench: 201.09 ns/iter (+/- 8.97)
test decode::hex::bench2_256b ... bench: 1,866.91 ns/iter (+/- 27.74)
test decode::hex::bench3_2k ... bench: 18,459.65 ns/iter (+/- 132.40)
test decode::hex::bench4_16k ... bench: 156,200.02 ns/iter (+/- 1,087.62)
test decode::hex::bench5_128k ... bench: 1,259,235.00 ns/iter (+/- 16,768.44)
test decode::hex::bench6_1m ... bench: 10,090,523.50 ns/iter (+/- 24,818.34)
test decode::lowercase_hex::bench1_32b ... bench: 25.20 ns/iter (+/- 0.47)
test decode::lowercase_hex::bench2_256b ... bench: 85.39 ns/iter (+/- 0.68)
test decode::lowercase_hex::bench3_2k ... bench: 622.14 ns/iter (+/- 6.47)
test decode::lowercase_hex::bench4_16k ... bench: 4,480.13 ns/iter (+/- 63.32)
test decode::lowercase_hex::bench5_128k ... bench: 35,632.35 ns/iter (+/- 486.96)
test decode::lowercase_hex::bench6_1m ... bench: 311,295.43 ns/iter (+/- 16,437.37)
test decode_to_slice::faster_hex::bench1_32b ... bench: 16.51 ns/iter (+/- 0.06)
test decode_to_slice::faster_hex::bench2_256b ... bench: 85.09 ns/iter (+/- 1.64)
test decode_to_slice::faster_hex::bench3_2k ... bench: 614.88 ns/iter (+/- 6.42)
test decode_to_slice::faster_hex::bench4_16k ... bench: 4,825.86 ns/iter (+/- 85.11)
test decode_to_slice::faster_hex::bench5_128k ... bench: 38,357.67 ns/iter (+/- 972.51)
test decode_to_slice::faster_hex::bench6_1m ... bench: 330,883.88 ns/iter (+/- 32,079.73)
test decode_to_slice::hex::bench1_32b ... bench: 58.89 ns/iter (+/- 1.44)
test decode_to_slice::hex::bench2_256b ... bench: 610.67 ns/iter (+/- 15.75)
test decode_to_slice::hex::bench3_2k ... bench: 8,220.72 ns/iter (+/- 259.07)
test decode_to_slice::hex::bench4_16k ... bench: 103,786.71 ns/iter (+/- 2,026.26)
test decode_to_slice::hex::bench5_128k ... bench: 990,568.62 ns/iter (+/- 1,976.89)
test decode_to_slice::hex::bench6_1m ... bench: 7,876,872.30 ns/iter (+/- 18,905.00)
test decode_to_slice::lowercase_hex::bench1_32b ... bench: 13.88 ns/iter (+/- 0.05)
test decode_to_slice::lowercase_hex::bench2_256b ... bench: 71.47 ns/iter (+/- 0.83)
test decode_to_slice::lowercase_hex::bench3_2k ... bench: 572.47 ns/iter (+/- 76.37)
test decode_to_slice::lowercase_hex::bench4_16k ... bench: 4,507.82 ns/iter (+/- 90.16)
test decode_to_slice::lowercase_hex::bench5_128k ... bench: 35,963.28 ns/iter (+/- 373.01)
test decode_to_slice::lowercase_hex::bench6_1m ... bench: 320,093.83 ns/iter (+/- 75,070.88)
test encode::faster_hex::bench1_32b ... bench: 29.90 ns/iter (+/- 0.34)
test encode::faster_hex::bench2_256b ... bench: 58.10 ns/iter (+/- 1.71)
test encode::faster_hex::bench3_2k ... bench: 313.61 ns/iter (+/- 5.77)
test encode::faster_hex::bench4_16k ... bench: 2,119.70 ns/iter (+/- 67.17)
test encode::faster_hex::bench5_128k ... bench: 16,664.43 ns/iter (+/- 456.81)
test encode::faster_hex::bench6_1m ... bench: 178,190.80 ns/iter (+/- 29,494.59)
test encode::hex::bench1_32b ... bench: 191.27 ns/iter (+/- 6.92)
test encode::hex::bench2_256b ... bench: 1,318.34 ns/iter (+/- 73.17)
test encode::hex::bench3_2k ... bench: 10,176.20 ns/iter (+/- 523.88)
test encode::hex::bench4_16k ... bench: 82,000.56 ns/iter (+/- 1,539.21)
test encode::hex::bench5_128k ... bench: 655,616.70 ns/iter (+/- 16,414.17)
test encode::hex::bench6_1m ... bench: 5,435,120.10 ns/iter (+/- 369,061.12)
test encode::lowercase_hex::bench1_32b ... bench: 12.54 ns/iter (+/- 0.17)
test encode::lowercase_hex::bench2_256b ... bench: 26.46 ns/iter (+/- 0.11)
test encode::lowercase_hex::bench3_2k ... bench: 166.18 ns/iter (+/- 4.83)
test encode::lowercase_hex::bench4_16k ... bench: 1,095.94 ns/iter (+/- 32.44)
test encode::lowercase_hex::bench5_128k ... bench: 8,516.21 ns/iter (+/- 331.74)
test encode::lowercase_hex::bench6_1m ... bench: 98,046.15 ns/iter (+/- 17,868.56)
test encode_to_slice::faster_hex::bench1_32b ... bench: 10.94 ns/iter (+/- 0.05)
test encode_to_slice::faster_hex::bench2_256b ... bench: 29.70 ns/iter (+/- 0.22)
test encode_to_slice::faster_hex::bench3_2k ... bench: 197.90 ns/iter (+/- 7.33)
test encode_to_slice::faster_hex::bench4_16k ... bench: 1,506.35 ns/iter (+/- 36.96)
test encode_to_slice::faster_hex::bench5_128k ... bench: 12,016.58 ns/iter (+/- 317.24)
test encode_to_slice::faster_hex::bench6_1m ... bench: 122,383.91 ns/iter (+/- 17,791.74)
test encode_to_slice::hex::bench1_32b ... bench: 31.84 ns/iter (+/- 1.28)
test encode_to_slice::hex::bench2_256b ... bench: 179.54 ns/iter (+/- 7.68)
test encode_to_slice::hex::bench3_2k ... bench: 1,398.08 ns/iter (+/- 30.64)
test encode_to_slice::hex::bench4_16k ... bench: 11,089.17 ns/iter (+/- 205.89)
test encode_to_slice::hex::bench5_128k ... bench: 89,321.90 ns/iter (+/- 2,078.97)
test encode_to_slice::hex::bench6_1m ... bench: 768,422.28 ns/iter (+/- 27,858.36)
test encode_to_slice::lowercase_hex::bench1_32b ... bench: 8.80 ns/iter (+/- 0.04)
test encode_to_slice::lowercase_hex::bench2_256b ... bench: 20.00 ns/iter (+/- 0.56)
test encode_to_slice::lowercase_hex::bench3_2k ... bench: 135.98 ns/iter (+/- 2.71)
test encode_to_slice::lowercase_hex::bench4_16k ... bench: 1,069.21 ns/iter (+/- 34.54)
test encode_to_slice::lowercase_hex::bench5_128k ... bench: 8,525.84 ns/iter (+/- 302.04)
test encode_to_slice::lowercase_hex::bench6_1m ... bench: 100,242.20 ns/iter (+/- 29,819.70)
test format::lowercase_hex::bench1_32b ... bench: 18.90 ns/iter (+/- 0.44)
test format::lowercase_hex::bench2_256b ... bench: 52.15 ns/iter (+/- 1.66)
test format::lowercase_hex::bench3_2k ... bench: 295.99 ns/iter (+/- 11.75)
test format::lowercase_hex::bench4_16k ... bench: 2,266.58 ns/iter (+/- 76.90)
test format::lowercase_hex::bench5_128k ... bench: 19,151.19 ns/iter (+/- 442.19)
test format::lowercase_hex::bench6_1m ... bench: 582,283.03 ns/iter (+/- 244,417.02)
test format::std::bench1_32b ... bench: 817.64 ns/iter (+/- 1,609.66)
test format::std::bench2_256b ... bench: 5,599.23 ns/iter (+/- 1,526.70)
test format::std::bench3_2k ... bench: 46,168.31 ns/iter (+/- 17,688.12)
test format::std::bench4_16k ... bench: 354,106.31 ns/iter (+/- 16,870.09)
test format::std::bench5_128k ... bench: 2,861,531.80 ns/iter (+/- 79,434.52)
test format::std::bench6_1m ... bench: 23,120,824.60 ns/iter (+/- 409,923.02)
```
#### License
<sup>
Licensed under either of <a href="LICENSE-APACHE">Apache License, Version
2.0</a> or <a href="LICENSE-MIT">MIT license</a> at your option.
</sup>
<br>
<sub>
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.
</sub>