Struct arrayvec::ArrayString

source · [−]

pub struct ArrayString<const CAP: usize> { /* private fields */ }

Expand description

A string with a fixed capacity.

The ArrayString is a string backed by a fixed size array. It keeps track of its length, and is parameterized by CAP for the maximum capacity.

CAP is of type usize but is range limited to u32::MAX; attempting to create larger arrayvecs with larger capacity will panic.

The string is a contiguous value that you can store directly on the stack if needed.

Implementations

source

impl<const CAP: usize> ArrayString<CAP>

source

pub fn new() -> ArrayString<CAP>

Create a new empty ArrayString.

Capacity is inferred from the type parameter.

use arrayvec::ArrayString;

let mut string = ArrayString::<16>::new();
string.push_str("foo");
assert_eq!(&string[..], "foo");
assert_eq!(string.capacity(), 16);

source

pub const fn new_const() -> ArrayString<CAP>

Create a new empty ArrayString (const fn).

Capacity is inferred from the type parameter.

use arrayvec::ArrayString;

static ARRAY: ArrayString<1024> = ArrayString::new_const();

source

pub const fn len(&self) -> usize

Return the length of the string.

source

pub const fn is_empty(&self) -> bool

Returns whether the string is empty.

source

pub fn from(s: &str) -> Result<Self, CapacityError<&str>>

Create a new ArrayString from a str.

Capacity is inferred from the type parameter.

Errors if the backing array is not large enough to fit the string.

use arrayvec::ArrayString;

let mut string = ArrayString::<3>::from("foo").unwrap();
assert_eq!(&string[..], "foo");
assert_eq!(string.len(), 3);
assert_eq!(string.capacity(), 3);

source

pub fn from_byte_string(b: &[u8 ; CAP]) -> Result<Self, Utf8Error>

Create a new ArrayString from a byte string literal.

Errors if the byte string literal is not valid UTF-8.

use arrayvec::ArrayString;

let string = ArrayString::from_byte_string(b"hello world").unwrap();

source

pub fn zero_filled() -> Self

Create a new ArrayString value fully filled with ASCII NULL characters (\0). Useful to be used as a buffer to collect external data or as a buffer for intermediate processing.

use arrayvec::ArrayString;

let string = ArrayString::<16>::zero_filled();
assert_eq!(string.len(), 16);

source

pub const fn capacity(&self) -> usize

Return the capacity of the ArrayString.

use arrayvec::ArrayString;

let string = ArrayString::<3>::new();
assert_eq!(string.capacity(), 3);

source

pub const fn is_full(&self) -> bool

Return if the ArrayString is completely filled.

use arrayvec::ArrayString;

let mut string = ArrayString::<1>::new();
assert!(!string.is_full());
string.push_str("A");
assert!(string.is_full());

source

pub const fn remaining_capacity(&self) -> usize

Returns the capacity left in the ArrayString.

use arrayvec::ArrayString;

let mut string = ArrayString::<3>::from("abc").unwrap();
string.pop();
assert_eq!(string.remaining_capacity(), 1);

source

pub fn push(&mut self, c: char)

Adds the given char to the end of the string.

Panics if the backing array is not large enough to fit the additional char.

use arrayvec::ArrayString;

let mut string = ArrayString::<2>::new();

string.push('a');
string.push('b');

assert_eq!(&string[..], "ab");

source

pub fn try_push(&mut self, c: char) -> Result<(), CapacityError<char>>

Adds the given char to the end of the string.

Returns Ok if the push succeeds.

Errors if the backing array is not large enough to fit the additional char.

use arrayvec::ArrayString;

let mut string = ArrayString::<2>::new();

string.try_push('a').unwrap();
string.try_push('b').unwrap();
let overflow = string.try_push('c');

assert_eq!(&string[..], "ab");
assert_eq!(overflow.unwrap_err().element(), 'c');

source

pub fn push_str(&mut self, s: &str)

Adds the given string slice to the end of the string.

Panics if the backing array is not large enough to fit the string.

use arrayvec::ArrayString;

let mut string = ArrayString::<2>::new();

string.push_str("a");
string.push_str("d");

assert_eq!(&string[..], "ad");

source

pub fn try_push_str<'a>(
&mut self,
s: &'a str
) -> Result<(), CapacityError<&'a str>>

Adds the given string slice to the end of the string.

Returns Ok if the push succeeds.

Errors if the backing array is not large enough to fit the string.

use arrayvec::ArrayString;

let mut string = ArrayString::<2>::new();

string.try_push_str("a").unwrap();
let overflow1 = string.try_push_str("bc");
string.try_push_str("d").unwrap();
let overflow2 = string.try_push_str("ef");

assert_eq!(&string[..], "ad");
assert_eq!(overflow1.unwrap_err().element(), "bc");
assert_eq!(overflow2.unwrap_err().element(), "ef");

source

pub fn pop(&mut self) -> Option<char>

Removes the last character from the string and returns it.

Returns None if this ArrayString is empty.

use arrayvec::ArrayString;
 
let mut s = ArrayString::<3>::from("foo").unwrap();

assert_eq!(s.pop(), Some('o'));
assert_eq!(s.pop(), Some('o'));
assert_eq!(s.pop(), Some('f'));

assert_eq!(s.pop(), None);

source

pub fn truncate(&mut self, new_len: usize)

Shortens this ArrayString to the specified length.

If new_len is greater than the string’s current length, this has no effect.

Panics if new_len does not lie on a char boundary.

use arrayvec::ArrayString;

let mut string = ArrayString::<6>::from("foobar").unwrap();
string.truncate(3);
assert_eq!(&string[..], "foo");
string.truncate(4);
assert_eq!(&string[..], "foo");

source

pub fn remove(&mut self, idx: usize) -> char

Removes a char from this ArrayString at a byte position and returns it.

This is an O(n) operation, as it requires copying every element in the array.

Panics if idx is larger than or equal to the ArrayString’s length, or if it does not lie on a char boundary.

use arrayvec::ArrayString;
 
let mut s = ArrayString::<3>::from("foo").unwrap();

assert_eq!(s.remove(0), 'f');
assert_eq!(s.remove(1), 'o');
assert_eq!(s.remove(0), 'o');