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

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

Create a new class from an existing set of ranges.

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

Returns true if b is matched by this byte class.

pub 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.

pub 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().

pub 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>>

pub 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);

pub 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();

pub fn as_ptr(&self) -> *const T

Returns a raw pointer to the vector's buffer.

The caller must ensure that the vector outlives the pointer this function returns, or else it will end up pointing to garbage. Modifying the vector may cause its buffer to be reallocated, which would also make any pointers to it invalid.

The caller must also ensure that the memory the pointer (non-transitively) points to is never written to (except inside an UnsafeCell) using this pointer or any pointer derived from it. If you need to mutate the contents of the slice, use as_mut_ptr.

Examples

let x = vec![1, 2, 4];
let x_ptr = x.as_ptr();

unsafe {
    for i in 0..x.len() {
        assert_eq!(*x_ptr.add(i), 1 << i);
    }
}

pub fn len(&self) -> usize

Returns the number of elements in the vector, also referred to as its 'length'.

Examples

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

pub 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 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 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 Eq for ByteClass

impl PartialEq<ByteClass> for ByteClass

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

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

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

This method tests for !=.

impl Display for ByteClass

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

Formats the value using the given formatter.

impl Debug for ByteClass

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

Formats the value using the given formatter.

impl Deref for ByteClass

type Target = Vec<ByteRange>

The resulting type after dereferencing.

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

Dereferences the value.

impl StructuralPartialEq for ByteClass

impl StructuralEq for ByteClass