Struct toolshed::NulTermStr

pub struct NulTermStr<'arena>(_);

A wrapper around a str slice that has an extra 0 byte allocated following its contents.

Methods

impl<'arena> NulTermStr<'arena>

pub unsafe fn byte_unchecked(&self, index: usize) -> u8

Read byte at a given index. This does not check for length boundaries, but is guaranteed to return 0 for index equal to the length.

This can be a very useful optimization when reading a long string one byte at a time until termination, if checking for 0 can replace what would otherwise have to be length checks.

let arena = Arena::new();
let str = arena.alloc_nul_term_str("foo");

// We can safely get the underlying `&str` at any time.
assert_eq!(&str[..], "foo");

unsafe {
    // First 3 bytes are known to us
    assert_eq!(str.byte_unchecked(0), b'f');
    assert_eq!(str.byte_unchecked(1), b'o');
    assert_eq!(str.byte_unchecked(2), b'o');

    // Following is safe and guaranteed to be '0'
    assert_eq!(str.byte_unchecked(3), 0);

    // Reading index 4 would be undefined behavior!
}

Trait Implementations

impl<'arena> PartialEq<NulTermStr<'arena>> for NulTermStr<'arena>

fn eq(&self, other: &NulTermStr<'arena>) -> bool

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

fn ne(&self, other: &NulTermStr<'arena>) -> bool

This method tests for !=.

impl<'arena> Copy for NulTermStr<'arena>

impl<'arena> Clone for NulTermStr<'arena>

fn clone(&self) -> NulTermStr<'arena>

Returns a copy of the value.

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

Performs copy-assignment from source.

impl<'arena> AsRef<str> for NulTermStr<'arena>

fn as_ref(&self) -> &str

Performs the conversion.

impl<'arena> From<NulTermStr<'arena>> for &'arena str

fn from(nts: NulTermStr<'arena>) -> &'arena str

Performs the conversion.

impl<'arena> Deref for NulTermStr<'arena>

type Target = &'arena str

The resulting type after dereferencing.

fn deref(&self) -> &&'arena str

Dereferences the value.

impl<'arena> Debug for NulTermStr<'arena>

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

Formats the value using the given formatter.

impl<'arena> Display for NulTermStr<'arena>

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

Formats the value using the given formatter.