capnp 0.25.4

runtime library for Cap'n Proto data encoding
Documentation 
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pub trait Primitive {
    type Raw;

    /// Reads the value, swapping bytes on big-endian processors.
    fn get(raw: &Self::Raw) -> Self;

    /// Writes the value, swapping bytes on big-endian processors.
    fn set(raw: &mut Self::Raw, value: Self);
}

#[cfg(feature = "unaligned")]
macro_rules! primitive_impl(
    ($typ:ty, $n:expr) => (
        impl Primitive for $typ {
            type Raw = [u8; $n];

            #[inline]
            fn get(raw: &Self::Raw) -> Self {
                <$typ>::from_le_bytes(*raw)
            }

            #[inline]
            fn set(raw: &mut Self::Raw, value: Self) {
                *raw = value.to_le_bytes();
            }
        }
        );
    );

#[cfg(not(feature = "unaligned"))]
macro_rules! primitive_impl(
    ($typ:ty, $n:expr) => (
        impl Primitive for $typ {
            type Raw = Self;

            #[inline]
            fn get(raw: &Self::Raw) -> Self {
                raw.to_le()
            }

            #[inline]
            fn set(raw: &mut Self::Raw, value: Self) {
                *raw = value.to_le()
            }
        }
        );
    );

primitive_impl!(u8, 1);
primitive_impl!(i8, 1);
primitive_impl!(u16, 2);
primitive_impl!(i16, 2);
primitive_impl!(u32, 4);
primitive_impl!(i32, 4);
primitive_impl!(u64, 8);
primitive_impl!(i64, 8);

#[cfg(feature = "unaligned")]
primitive_impl!(f32, 4);

#[cfg(feature = "unaligned")]
primitive_impl!(f64, 8);

#[cfg(not(feature = "unaligned"))]
impl Primitive for f32 {
    type Raw = Self;

    #[inline]
    fn get(raw: &Self::Raw) -> Self {
        Self::from_bits(raw.to_bits().to_le())
    }

    #[inline]
    fn set(raw: &mut Self::Raw, value: Self) {
        *raw = Self::from_bits(value.to_bits().to_le())
    }
}

#[cfg(not(feature = "unaligned"))]
impl Primitive for f64 {
    type Raw = Self;

    #[inline]
    fn get(raw: &Self::Raw) -> Self {
        Self::from_bits(raw.to_bits().to_le())
    }

    #[inline]
    fn set(raw: &mut Self::Raw, value: Self) {
        *raw = Self::from_bits(value.to_bits().to_le())
    }
}

/// A value casted directly from a little-endian byte buffer. On big-endian
/// processors, the bytes of the value need to be swapped upon reading and writing.
#[repr(C)]
pub(crate) struct WireValue<T>
where
    T: Primitive,
{
    value: <T as Primitive>::Raw,
}

impl<T> WireValue<T>
where
    T: Primitive,
{
    /// Reads the value, swapping bytes on big-endian processors.
    #[inline]
    pub(crate) fn get(&self) -> T {
        <T as Primitive>::get(&self.value)
    }

    /// Writes the value, swapping bytes on big-endian processors.
    #[inline]
    pub(crate) fn set(&mut self, value: T) {
        <T as Primitive>::set(&mut self.value, value)
    }
}