Struct smartstring::Compact

pub struct Compact;

A compact string representation equal to String in size with guaranteed inlining.

This representation relies on pointer alignment to be able to store a discriminant bit in its inline form that will never be present in its String form, thus giving us 24 bytes on 64-bit architectures, and 12 bytes on 32-bit, minus one bit, to encode our inline string. It uses the rest of the discriminant bit’s byte to encode the string length, and the remaining bytes (23 or 11 depending on arch) to store the string data. When the available space is exceeded, it swaps itself out with a String containing its previous contents, relying on the discriminant bit in the String’s pointer to be unset, so we can store the String safely without taking up any extra space for a discriminant.

This performs generally as well as String on all ops on boxed strings, and better than Strings on inlined strings.

Trait Implementations

impl Debug for Compact

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

Formats the value using the given formatter.

impl SmartStringMode for Compact

type BoxedString = String

The boxed string type for this layout.

type InlineArray = [u8; 11]

The inline string type for this layout.

const DEALLOC: bool

A constant to decide whether to turn a wrapped string back into an inlined string whenever possible (true) or leave it as a wrapped string once wrapping has occurred (false).