This commit does a number of manual fixups to the code after the
previous two commits were done via 'cargo fix' automatically.
Actually, this contains more 'cargo fix' annotations, since I had
forgotten to add 'edition = "2018"' to all sub-crates.
This was using `Vec::extend` to accumulate bytes in a buffer, but this
compiles down to less efficient code than, say, `Vec::extend_from_slice`.
However, that method is newly available as of Rust 1.6, so we do a small
backport to regain performance.
This bug was noticed by @llogiq here: https://github.com/TeXitoi/benchmarksgame-rs/issues/31
In particular, this increases the performance of bytes::Regex two-fold on
that benchmark.
This commit enables support for compiling regular expressions that can
match on arbitrary byte slices. In particular, we add a new sub-module
called `bytes` that duplicates the API of the top-level module, except
`&str` for subjects is replaced by `&[u8]`. Additionally, Unicode
support in the regular expression is disabled by default but can be
selectively re-enabled with the `u` flag. (Unicode support cannot be
selectively disabled in the standard top-level API.)
Most of the interesting changes occurred in the `regex-syntax` crate,
where the AST now explicitly distinguishes between "ASCII compatible"
expressions and Unicode aware expressions.
This PR makes a few other changes out of convenience:
1. The DFA now knows how to "give up" if it's flushing its cache too
often. When the DFA gives up, either backtracking or the NFA algorithm
take over, which provides better performance.
2. Benchmarks were added for Oniguruma.
3. The benchmarks in general were overhauled to be defined in one place
by using conditional compilation.
4. The tests have been completely reorganized to make it easier to split
up the tests depending on which regex engine we're using. For example,
we occasionally need to be able to write tests specifically for
`regex::Regex` or specifically for `regex::bytes::Regex`.
5. Fixes a bug where NUL bytes weren't represented correctly in the byte
class optimization for the DFA.
Closes#85.
