Jetscii

A tiny library to efficiently search strings for ASCII characters.

Documentation

Example

rust use jetscii::AsciiChars; let mut search = AsciiChars::new(); search.push(b'-'); search.push(b':'); let part_number = "86-J52:rev1"; let parts: Vec<_> = part_number.split(search).collect(); assert_eq!(&parts, &["86", "J52", "rev1"]);

What's so special about this library?

We use a particular x86-64 SSE 4.2 instruction (PCMPESTRI) to gain great speedups. This method stays fast even when searching for one character in a set of up to 8 choices.

When PCMPESTRI is not available, we fall back to a universally-supported byte iterator method.

Benchmarks

Single character

Searching a 5MiB string of as with a single space at the end:

| Method | Speed | |--------------------------------------------------|-----------| | str.find(AsciiChars) | 6501 MB/s | | str.as_bytes().iter().position(|&v| v == b' ') | 1620 MB/s | | str.find(|c| c == ' ') | 1090 MB/s | | str.find(' ') | 1085 MB/s | | str.find(&[' '][..]) | 602 MB/s | | str.find(" ") | 293 MB/s |

Set of characters

Searching a 5MiB string of as with a single ampersand at the end:

| Method | Speed | |--------------------------------------------------|-----------| | str.find(AsciiChars) | 6480 MB/s | | str.as_bytes().iter().position(|&v| ...) | 1620 MB/s | | str.find(|c| ...) | 1022 MB/s | | str.find(&['<', '>', '&'][..]) | 361 MB/s |

Contributing

1. Fork it ( https://github.com/shepmaster/jetscii/fork )
2. Create your feature branch (git checkout -b my-new-feature)
3. Add a failing test.
4. Add code to pass the test.
5. Commit your changes (git commit -am 'Add some feature')
6. Ensure tests pass.
7. Push to the branch (git push origin my-new-feature)
8. Create a new Pull Request