Struct coap_handler::helpers::Block2RequestData

pub struct Block2RequestData { /* fields omitted */ }

Request data from a Block2 request

As the M flag is unused in requests, it is not captured in here (and ignored at construction).

Implementations

impl Block2RequestData

pub fn from_message<'a>(
    message: &'a impl ReadableMessage<'a>
) -> Result<Self, ()>

Extract a request block 2 value from a request message.

Absence of the option is not an error and results in the default value to be returned; exceeding length or duplicate entries are an error and are indicated by returning an error, which should be responded to with a Bad Option error.

pub fn from_option<'a>(option: &'a impl MessageOption) -> Result<Self, ()>

Extract a request block 2 value from a single option. An error is indicated on a malformed (ie. overly long) option.

Compared to Block2RequestData::from_message(), this can easily be packed into a single loop that processes all options and fails on unknown critical ones; on the other hand, this does not automate the check for duplicate options.

Panics

In debug mode if the option is not Block2

pub fn size(&self) -> u16

Size of a single block

pub fn before(&self) -> u32

Number of bytes before the indicated block

pub fn shrink(mut self: Self, size: u16) -> Option<Self>

Return a block that has identical .before(), but a block size smaller or equal to the given one.

Returns None if the given size is not expressible as a CoAP block (ie. is less than 16).

Trait Implementations

impl Default for Block2RequestData

fn default() -> Self

Returns the "default value" for a type.