// Copyright 2014-2015 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
macro_rules! define_set {
($name:ident, $exec_build:expr, $text_ty:ty, $as_bytes:expr) => {
pub mod $name {
use std::fmt;
use std::iter;
use std::slice;
use std::vec;
use error::Error;
use exec::{Exec, ExecBuilder};
use re_trait::RegularExpression;
/// Match multiple (possibly overlapping) regular expressions in a single scan.
///
/// A regex set corresponds to the union of two or more regular expressions.
/// That is, a regex set will match text where at least one of its
/// constituent regular expressions matches. A regex set as its formulated here
/// provides a touch more power: it will also report *which* regular
/// expressions in the set match. Indeed, this is the key difference between
/// regex sets and a single `Regex` with many alternates, since only one
/// alternate can match at a time.
///
/// For example, consider regular expressions to match email addresses and
/// domains: `[a-z]+@[a-z]+\.(com|org|net)` and `[a-z]+\.(com|org|net)`. If a
/// regex set is constructed from those regexes, then searching the text
/// `foo@example.com` will report both regexes as matching. Of course, one
/// could accomplish this by compiling each regex on its own and doing two
/// searches over the text. The key advantage of using a regex set is that it
/// will report the matching regexes using a *single pass through the text*.
/// If one has hundreds or thousands of regexes to match repeatedly (like a URL
/// router for a complex web application or a user agent matcher), then a regex
/// set can realize huge performance gains.
///
/// # Example
///
/// This shows how the above two regexes (for matching email addresses and
/// domains) might work:
///
/// ```rust
/// # use regex::RegexSet;
/// let set = RegexSet::new(&[
/// r"[a-z]+@[a-z]+\.(com|org|net)",
/// r"[a-z]+\.(com|org|net)",
/// ]).unwrap();
///
/// // Ask whether any regexes in the set match.
/// assert!(set.is_match("foo@example.com"));
///
/// // Identify which regexes in the set match.
/// let matches: Vec<_> = set.matches("foo@example.com").into_iter().collect();
/// assert_eq!(vec![0, 1], matches);
///
/// // Try again, but with text that only matches one of the regexes.
/// let matches: Vec<_> = set.matches("example.com").into_iter().collect();
/// assert_eq!(vec![1], matches);
///
/// // Try again, but with text that doesn't match any regex in the set.
/// let matches: Vec<_> = set.matches("example").into_iter().collect();
/// assert!(matches.is_empty());
/// ```
///
/// Note that it would be possible to adapt the above example to using `Regex`
/// with an expression like:
///
/// ```ignore
/// (?P<email>[a-z]+@(?P<email_domain>[a-z]+[.](com|org|net)))|(?P<domain>[a-z]+[.](com|org|net))
/// ```
///
/// After a match, one could then inspect the capture groups to figure out
/// which alternates matched. The problem is that it is hard to make this
/// approach scale when there are many regexes since the overlap between each
/// alternate isn't always obvious to reason about.
///
/// # Limitations
///
/// Regex sets are limited to answering the following two questions:
///
/// 1. Does any regex in the set match?
/// 2. If so, which regexes in the set match?
///
/// As with the main `Regex` type, it is cheaper to ask (1) instead of (2)
/// since the matching engines can stop after the first match is found.
///
/// Other features like finding the location of successive matches or their
/// sub-captures aren't supported. If you need this functionality, the
/// recommended approach is to compile each regex in the set independently and
/// selectively match them based on which regexes in the set matched.
///
/// # Performance
///
/// A `RegexSet` has the same performance characteristics as `Regex`. Namely,
/// search takes `O(mn)` time, where `m` is proportional to the size of the
/// regex set and `n` is proportional to the length of the search text.
#[derive(Clone)]
pub struct RegexSet(Exec);
impl RegexSet {
/// Create a new regex set with the given regular expressions.
///
/// This takes an iterator of `S`, where `S` is something that can produce
/// a `&str`. If any of the strings in the iterator are not valid regular
/// expressions, then an error is returned.
///
/// # Example
///
/// Create a new regex set from an iterator of strings:
///
/// ```rust
/// # use regex::RegexSet;
/// let set = RegexSet::new(&[r"\w+", r"\d+"]).unwrap();
/// assert!(set.is_match("foo"));
/// ```
pub fn new<I, S>(exprs: I) -> Result<RegexSet, Error>
where S: AsRef<str>, I: IntoIterator<Item=S> {
let exec = try!($exec_build(exprs));
Ok(RegexSet(exec))
}
/// Returns true if and only if one of the regexes in this set matches
/// the text given.
///
/// This method should be preferred if you only need to test whether any
/// of the regexes in the set should match, but don't care about *which*
/// regexes matched. This is because the underlying matching engine will
/// quit immediately after seeing the first match instead of continuing to
/// find all matches.
///
/// Note that as with searches using `Regex`, the expression is unanchored
/// by default. That is, if the regex does not start with `^` or `\A`, or
/// end with `$` or `\z`, then it is permitted to match anywhere in the
/// text.
///
/// # Example
///
/// Tests whether a set matches some text:
///
/// ```rust
/// # use regex::RegexSet;
/// let set = RegexSet::new(&[r"\w+", r"\d+"]).unwrap();
/// assert!(set.is_match("foo"));
/// assert!(!set.is_match("☃"));
/// ```
pub fn is_match(&self, text: $text_ty) -> bool {
self.0.searcher().is_match_at($as_bytes(text), 0)
}
/// Returns the set of regular expressions that match in the given text.
///
/// The set returned contains the index of each regular expression that
/// matches in the given text. The index is in correspondence with the
/// order of regular expressions given to `RegexSet`'s constructor.
///
/// The set can also be used to iterate over the matched indices.
///
/// Note that as with searches using `Regex`, the expression is unanchored
/// by default. That is, if the regex does not start with `^` or `\A`, or
/// end with `$` or `\z`, then it is permitted to match anywhere in the
/// text.
///
/// # Example
///
/// Tests which regular expressions match the given text:
///
/// ```rust
/// # use regex::RegexSet;
/// let set = RegexSet::new(&[
/// r"\w+",
/// r"\d+",
/// r"\pL+",
/// r"foo",
/// r"bar",
/// r"barfoo",
/// r"foobar",
/// ]).unwrap();
/// let matches: Vec<_> = set.matches("foobar").into_iter().collect();
/// assert_eq!(matches, vec![0, 2, 3, 4, 6]);
///
/// // You can also test whether a particular regex matched:
/// let matches = set.matches("foobar");
/// assert!(!matches.matched(5));
/// assert!(matches.matched(6));
/// ```
pub fn matches(&self, text: $text_ty) -> SetMatches {
let mut matches = vec![false; self.0.regex_strings().len()];
let any = self.0.searcher().many_matches_at(
&mut matches, $as_bytes(text), 0);
SetMatches {
matched_any: any,
matches: matches,
}
}
/// Returns the total number of regular expressions in this set.
pub fn len(&self) -> usize {
self.0.regex_strings().len()
}
}
/// A set of matches returned by a regex set.
#[derive(Clone, Debug)]
pub struct SetMatches {
matched_any: bool,
matches: Vec<bool>,
}
impl SetMatches {
/// Whether this set contains any matches.
pub fn matched_any(&self) -> bool {
self.matched_any
}
/// Whether the regex at the given index matched.
///
/// The index for a regex is determined by its insertion order upon the
/// initial construction of a `RegexSet`, starting at `0`.
///
/// # Panics
///
/// If `regex_index` is greater than or equal to `self.len()`.
pub fn matched(&self, regex_index: usize) -> bool {
self.matches[regex_index]
}
/// The total number of regexes in the set that created these matches.
pub fn len(&self) -> usize {
self.matches.len()
}
/// Returns an iterator over indexes in the regex that matched.
pub fn iter(&self) -> SetMatchesIter {
SetMatchesIter((&*self.matches).into_iter().enumerate())
}
}
impl IntoIterator for SetMatches {
type IntoIter = SetMatchesIntoIter;
type Item = usize;
fn into_iter(self) -> Self::IntoIter {
SetMatchesIntoIter(self.matches.into_iter().enumerate())
}
}
impl<'a> IntoIterator for &'a SetMatches {
type IntoIter = SetMatchesIter<'a>;
type Item = usize;
fn into_iter(self) -> Self::IntoIter {
self.iter()
}
}
/// An owned iterator over the set of matches from a regex set.
pub struct SetMatchesIntoIter(iter::Enumerate<vec::IntoIter<bool>>);
impl Iterator for SetMatchesIntoIter {
type Item = usize;
fn next(&mut self) -> Option<usize> {
loop {
match self.0.next() {
None => return None,
Some((_, false)) => {}
Some((i, true)) => return Some(i),
}
}
}
}
impl DoubleEndedIterator for SetMatchesIntoIter {
fn next_back(&mut self) -> Option<usize> {
loop {
match self.0.next_back() {
None => return None,
Some((_, false)) => {}
Some((i, true)) => return Some(i),
}
}
}
}
/// A borrowed iterator over the set of matches from a regex set.
///
/// The lifetime `'a` refers to the lifetime of a `SetMatches` value.
#[derive(Clone)]
pub struct SetMatchesIter<'a>(iter::Enumerate<slice::Iter<'a, bool>>);
impl<'a> Iterator for SetMatchesIter<'a> {
type Item = usize;
fn next(&mut self) -> Option<usize> {
loop {
match self.0.next() {
None => return None,
Some((_, &false)) => {}
Some((i, &true)) => return Some(i),
}
}
}
}
impl<'a> DoubleEndedIterator for SetMatchesIter<'a> {
fn next_back(&mut self) -> Option<usize> {
loop {
match self.0.next_back() {
None => return None,
Some((_, &false)) => {}
Some((i, &true)) => return Some(i),
}
}
}
}
#[doc(hidden)]
impl From<Exec> for RegexSet {
fn from(exec: Exec) -> Self {
RegexSet(exec)
}
}
impl fmt::Debug for RegexSet {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
write!(f, "RegexSet({:?})", self.0.regex_strings())
}
}
#[allow(dead_code)] fn as_bytes_str(text: &str) -> &[u8] { text.as_bytes() }
#[allow(dead_code)] fn as_bytes_bytes(text: &[u8]) -> &[u8] { text }
}
}
}
define_set! {
unicode,
|exprs| ExecBuilder::new_many(exprs).build(),
&str,
as_bytes_str
}
define_set! {
bytes,
|exprs| ExecBuilder::new_many(exprs).only_utf8(false).build(),
&[u8],
as_bytes_bytes
}