utf8-ranges
===========
This crate converts contiguous ranges of Unicode scalar values to UTF-8 byte
ranges. This is useful when constructing byte based automata from Unicode.
Stated differently, this lets one embed UTF-8 decoding as part of one's
automaton.
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Dual-licensed under MIT or the [UNLICENSE](http://unlicense.org).
### Documentation
[http://burntsushi.net/rustdoc/utf8_ranges/](http://burntsushi.net/rustdoc/utf8_ranges/)
### Example
This shows how to convert a scalar value range (e.g., the basic multilingual
plane) to a sequence of byte based character classes.
```rust
extern crate utf8_ranges;
use utf8_ranges::Utf8Sequences;
fn main() {
for range in Utf8Sequences::new('\u{0}', '\u{FFFF}') {
println!("{:?}", range);
}
}
```
The output:
```
[0-7F]
[C2-DF][80-BF]
[E0][A0-BF][80-BF]
[E1-EC][80-BF][80-BF]
[ED][80-9F][80-BF]
[EE-EF][80-BF][80-BF]
```
These ranges can then be used to build an automaton. Namely:
1. Every arbitrary sequence of bytes matches exactly one of the sequences of
ranges or none of them.
2. Every match sequence of bytes is guaranteed to be valid UTF-8. (Erroneous
encodings of surrogate codepoints in UTF-8 cannot match any of the byte
ranges above.)