Struct StrObj 

pub struct StrObj {
    pub header: Header,
    pub len: usize,
    pub hash: AtomicU64,
    pub chars: AtomicU64,
    /* private fields */
}

A string: immutable UTF-8 bytes with a cached hash and character count.

Strings of at least StrObj::INDEX_MIN bytes get their character count when they are allocated. When such a string is not ASCII, its allocation also reserves a sparse index after the bytes: one u32 byte offset for every StrObj::STRIDEth character, filled in the first time a character position is looked up. That makes s[i] and slicing O(1) for ASCII strings (character count equals byte length) and O(STRIDE) for the rest.

Fields

header: Header

len: usize

hash: AtomicU64

Cached hash; 0 means not yet computed.

chars: AtomicU64

Cached char count plus one (0 means not yet computed), and StrObj::INDEX_READY once the char index has been filled in.

Implementations

impl StrObj

pub const BASE: usize

pub const INDEX_MIN: usize = 256

Strings at least this long have an eagerly computed char count, and an index if not ASCII.

pub const STRIDE: usize = 64

Characters per index entry.

pub fn alloc_size(&self) -> usize

Total bytes the object occupies (header, bytes and index padding included).

pub fn as_str(&self) -> &str

pub fn char_count(&self) -> usize

pub fn is_ascii(&self) -> bool

Whether every character is a single byte. O(1) once the char count is known.

pub fn byte_offset(&self, i: usize) -> usize

The byte offset of character i (i may equal the char count, giving the length).

O(1) for ASCII strings, O(StrObj::STRIDE) for indexed ones, O(n) for short ones.

pub fn char_offset(&self, b: usize) -> usize

The character position of byte offset b, which must be a char boundary.

pub fn char_at(&self, i: usize) -> &str

The ith character (i < char_count()).

pub fn char_slice(&self, start: usize, end: usize) -> &str

The characters [start, end) (clamped to the string).

pub fn hash_code(&self) -> u64