Struct Unpacker

pub struct Unpacker<'a>(/* private fields */);

Unpacker of POD values from a byte slice.

Any reads past the end of the slice return default values rather than panicking. The caller must check the error status at the end to determine whether all returned values were valid.

Little-endian encoding is assumed.

Implementations

impl<'a> Unpacker<'a>

pub const fn new(b: &'a [u8]) -> Self

Creates a new unpacker.

pub const fn invalid() -> Self

Creates an unpacker in an error state.

pub const fn into_inner(self) -> &'a [u8]

Returns the remaining byte slice, if any. The caller should use Self::is_ok() to check whether the returned slice is valid.

pub const fn len(&self) -> usize

Returns the remaining number of bytes.

pub const fn is_empty(&self) -> bool

Returns whether the byte slice is empty.

pub fn is_ok(&self) -> bool

Returns whether all reads were within the bounds of the original byte slice.

pub fn take(&mut self) -> Self

Returns the remaining byte slice in a new unpacker, leaving self empty. This is primarily useful in combination with map().

pub fn map<T>(self, f: impl FnOnce(&mut Self) -> T) -> Option<T>

Returns Some output of f, or None if f fails to consume the entire slice without reading past the end.

pub fn map_or<T>(self, default: T, f: impl FnOnce(&mut Self) -> T) -> T

Returns the output of f, or default if f fails to consume the entire slice without reading past the end.

pub fn map_or_else<T>( self, default: impl FnOnce() -> T, f: impl FnOnce(&mut Self) -> T, ) -> T

Returns the output of f, or the output of default() if f fails to consume the entire slice without reading past the end.

pub const fn split_at(&self, i: usize) -> (Self, Self)

Splits the remaining byte slice at i, and returns two new unpackers, both of which will be in an error state if len() < i.

pub fn skip(&mut self, n: usize) -> Option<Self>

Advances self by n bytes, returning a new unpacker for the skipped bytes or None if there is an insufficient number of bytes remaining, in which case any remaining bytes are discarded.

Examples

if let Some(mut hdr) = p.skip(2) {
    let _ = hdr.u16();
    assert!(hdr.is_ok() && p.is_ok());
} else {
    assert!(!p.is_ok());
}

pub fn bool(&mut self) -> bool

Returns the next u8 as a bool where any non-zero value is converted to true.

pub fn u8(&mut self) -> u8

Returns the next u8.

pub fn u16(&mut self) -> u16

Returns the next u16.

pub fn u32(&mut self) -> u32

Returns the next u32.

pub fn u64(&mut self) -> u64

Returns the next u64.

pub fn u128(&mut self) -> u128

Returns the next u128.

pub fn i8(&mut self) -> i8

Returns the next i8.

pub fn i16(&mut self) -> i16

Returns the next i16.

pub fn i32(&mut self) -> i32

Returns the next i32.

pub fn i64(&mut self) -> i64

Returns the next i64.

pub fn i128(&mut self) -> i128

Returns the next i128.

pub fn bytes<const N: usize>(&mut self) -> [u8; N]

Returns the next [u8; N] array.

pub unsafe fn read<T: Default>(&mut self) -> T

Returns the next T, or T::default() if there is an insufficient number of bytes remaining, in which case any remaining bytes are discarded.

Safety

T must be able to hold the resulting bit pattern.

Trait Implementations

impl<'a> AsRef<[u8]> for Unpacker<'a>

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

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

impl<'a> Clone for Unpacker<'a>

fn clone(&self) -> Unpacker<'a>

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<'a> Debug for Unpacker<'a>

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

Formats the value using the given formatter.

impl<'a> Default for Unpacker<'a>

fn default() -> Unpacker<'a>

Returns the “default value” for a type.

impl<'a> Hash for Unpacker<'a>

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl<'a> Ord for Unpacker<'a>

fn cmp(&self, other: &Unpacker<'a>) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized,

Restrict a value to a certain interval.

impl<'a> PartialEq for Unpacker<'a>

fn eq(&self, other: &Unpacker<'a>) -> bool

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

const 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<'a> PartialOrd for Unpacker<'a>

fn partial_cmp(&self, other: &Unpacker<'a>) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

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

Tests less than (for self and other) and is used by the < operator.

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

Tests less than or equal to (for self and other) and is used by the <= operator.

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

Tests greater than (for self and other) and is used by the > operator.

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

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl<'a> Copy for Unpacker<'a>

impl<'a> Eq for Unpacker<'a>

impl<'a> StructuralPartialEq for Unpacker<'a>