Struct regex_syntax::ByteClass

pub struct ByteClass { /* fields omitted */ }

A byte class for byte ranges only.

A byte class has a canonical format that the parser guarantees. Its canonical format is defined by the following invariants:

1. Given any byte, it is matched by at most one byte range in a canonical character class.
2. Every adjacent byte range is separated by at least one byte.
3. Given any pair of byte ranges r1 and r2, if r1.end < r2.start, then r1 comes before r2 in a canonical character class.

In sum, any ByteClass produced by this crate's parser is a sorted sequence of non-overlapping ranges. This makes it possible to test whether a byte is matched by a class with a binary search.

If the case insensitive flag was set when parsing a character class, then simple ASCII-only case folding is done automatically. For example, (?i)[a-c] is automatically translated to [a-cA-C].

Methods

impl ByteClass

fn new(ranges: Vec<ByteRange>) -> ByteClass

Create a new class from an existing set of ranges.

fn matches(&self, b: u8) -> bool

Returns true if b is matched by this byte class.

fn remove(&mut self, b: u8)

Removes the given byte from the class if it exists.

Note that this takes O(n) time in the number of ranges.

fn negate(self) -> ByteClass

Negates the byte class.

For all b where b is a byte, b matches self if and only if b does not match self.negate().

fn case_fold(self) -> ByteClass

Apply case folding to this byte class.

This assumes that the bytes in the ranges are ASCII compatible.

N.B. Applying case folding to a negated character class probably won't produce the expected result. e.g., (?i)[^x] really should match any character sans x and X, but if [^x] is negated before being case folded, you'll end up matching any character.

Methods from Deref<Target=Vec<ByteRange>>

fn capacity(&self) -> usize

Returns the number of elements the vector can hold without reallocating.

Examples

let vec: Vec<i32> = Vec::with_capacity(10);
assert_eq!(vec.capacity(), 10);

fn into_boxed_slice(self) -> Box<[T]>

Converts the vector into Box<[T]>.

Note that this will drop any excess capacity. Calling this and converting back to a vector with into_vec() is equivalent to calling shrink_to_fit().

Examples

let v = vec![1, 2, 3];

let slice = v.into_boxed_slice();

Any excess capacity is removed:

let mut vec = Vec::with_capacity(10);
vec.extend([1, 2, 3].iter().cloned());

assert_eq!(vec.capacity(), 10);
let slice = vec.into_boxed_slice();
assert_eq!(slice.into_vec().capacity(), 3);

fn as_slice(&self) -> &[T]

Extracts a slice containing the entire vector.

Equivalent to &s[..].

Examples

use std::io::{self, Write};
let buffer = vec![1, 2, 3, 5, 8];
io::sink().write(buffer.as_slice()).unwrap();

fn len(&self) -> usize

Returns the number of elements in the vector.

Examples

let a = vec![1, 2, 3];
assert_eq!(a.len(), 3);

fn is_empty(&self) -> bool

Returns true if the vector contains no elements.

Examples

let mut v = Vec::new();
assert!(v.is_empty());

v.push(1);
assert!(!v.is_empty());

Trait Implementations

impl Clone for ByteClass

fn clone(&self) -> ByteClass

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for ByteClass

fn fmt(&self, __arg_0: &mut Formatter) -> Result

Formats the value using the given formatter.

impl PartialEq for ByteClass

fn eq(&self, __arg_0: &ByteClass) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, __arg_0: &ByteClass) -> bool

This method tests for !=.

impl Eq for ByteClass

impl Deref for ByteClass

type Target = Vec<ByteRange>

The resulting type after dereferencing

fn deref(&self) -> &Vec<ByteRange>

The method called to dereference a value

impl IntoIterator for ByteClass

type Item = ByteRange

The type of the elements being iterated over.

type IntoIter = IntoIter<ByteRange>

Which kind of iterator are we turning this into?

fn into_iter(self) -> IntoIter<ByteRange>

Creates an iterator from a value.

impl<'a> IntoIterator for &'a ByteClass

type Item = &'a ByteRange

The type of the elements being iterated over.

type IntoIter = Iter<'a, ByteRange>

Which kind of iterator are we turning this into?

fn into_iter(self) -> Iter<'a, ByteRange>

Creates an iterator from a value.

impl Display for ByteClass

fn fmt(&self, f: &mut Formatter) -> Result

Formats the value using the given formatter.