Struct Usage 

pub struct Usage { /* private fields */ }

Usage index for an item usage; represents a suggested usage for the item or collection.

In the case where an item represents multiple controls, a Usage tag may suggest a usage for every variable or element in an array.

Data (Little Endian)

Depends on the value of UsagePage. See HID Usage Tables FOR Universal Serial Bus.

Implementations

impl Usage

pub const PREFIX: u8 = 8u8

Prefix consists of tag(bit 7-4), type(bit 3-2) and size(bit 1-0). The “size” part is set to 00 in this constant value.

pub fn new(raw: &[u8]) -> Result<Self, HidError>

Create an item with prefix check.

pub unsafe fn new_unchecked(raw: &[u8]) -> Self

Create an item WITHOUT prefix check.

Safety

Must ensure that the prefix part is correct.

pub fn prefix(&self) -> u8

Get prefix part of the item. Equivalent to item.as_ref()[0].

pub fn data(&self) -> &[u8]

Get data part of the item. Equivalent to &item.as_ref()[1..].

pub fn set_usage_page(&mut self, usage_page: UsagePage)

If you want more detailed content printed when formatting, you need to set the related usage page.

Equality

Equality between two Usage items ignores usage page.

pub fn usage_page(&self) -> Option<&UsagePage>

Get usage page.

pub fn new_with(data: &[u8]) -> Result<Self, HidError>

Create an item with specific data.

NOTE: data size must be: 0, 1, 2 or 4.

pub fn set_data(&mut self, data: &[u8]) -> Result<&mut Self, HidError>

Set data part of the item.

NOTE: data size must be: 0, 1, 2 or 4.

pub fn data_mut(&mut self) -> &mut [u8]

Get mutable data part of the item.

Trait Implementations

impl AsRef<[u8]> for Usage

fn as_ref(&self) -> &[u8]

Converts this type into a shared reference of the (usually inferred) input type.

impl Clone for Usage

fn clone(&self) -> Usage

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Usage

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

Formats the value using the given formatter.

impl Default for Usage

fn default() -> Self

Returns the “default value” for a type.

impl Display for Usage

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

Formats the value using the given formatter.

impl PartialEq for Usage

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

Tests for self and other values to be equal, and is used by ==.

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

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Eq for Usage