Trait Encode 

pub trait Encode: Clone {
    const SIZE: DataSize;
    const ALIGNMENT: PageOffset;

    // Required methods
    fn encode(&self) -> Cow<'_, [u8]>;
    fn decode(data: Cow<'_, [u8]>) -> MemoryResult<Self>
       where Self: Sized;
    fn size(&self) -> MSize;
}

This trait defines the encoding and decoding behaviour for data types used in the DBMS canister.

Required Associated Constants

const SIZE: DataSize

The size characteristic of the data type.

The DataSize can either be a fixed size in bytes or dynamic.

const ALIGNMENT: PageOffset

The alignment requirement in bytes for the data type.

If Self::SIZE is DataSize::Fixed, the alignment must be equal to the size, otherwise it can be any value.

This value should never be less than 8 for DataSize::Dynamic types to ensure proper memory alignment.

We should set a default value (probably 32) for dynamic types to avoid misalignment issues, but letting an expert user to override it if necessary.

Required Methods

fn encode(&self) -> Cow<'_, [u8]>

Encodes the data type into a vector of bytes.

fn decode(data: Cow<'_, [u8]>) -> MemoryResult<Self>

where Self: Sized,

Decodes the data type from a slice of bytes.

fn size(&self) -> MSize

Returns the size in bytes of the encoded data type.

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementors

impl Encode for Blob

const SIZE: DataSize = DataSize::Dynamic

const ALIGNMENT: PageOffset = 32u16

impl Encode for Boolean

const SIZE: DataSize

const ALIGNMENT: PageOffset = 1u16

impl Encode for Date

const SIZE: DataSize

const ALIGNMENT: PageOffset = 4u16

impl Encode for DateTime

const SIZE: DataSize

const ALIGNMENT: PageOffset = 13u16

impl Encode for Decimal

const SIZE: DataSize

const ALIGNMENT: PageOffset = 16u16

impl Encode for Int8

const SIZE: DataSize

const ALIGNMENT: PageOffset = 1u16

impl Encode for Int16

const SIZE: DataSize

const ALIGNMENT: PageOffset = 2u16

impl Encode for Int32

const SIZE: DataSize

const ALIGNMENT: PageOffset = 4u16

impl Encode for Int64

const SIZE: DataSize

const ALIGNMENT: PageOffset = 8u16

impl Encode for Principal

const SIZE: DataSize = DataSize::Dynamic

const ALIGNMENT: PageOffset = 32u16

impl Encode for Text

const SIZE: DataSize = DataSize::Dynamic

const ALIGNMENT: PageOffset = 32u16

impl Encode for Uint8

const SIZE: DataSize

const ALIGNMENT: PageOffset = 1u16

impl Encode for Uint16

const SIZE: DataSize

const ALIGNMENT: PageOffset = 2u16

impl Encode for Uint32

const SIZE: DataSize

const ALIGNMENT: PageOffset = 4u16

impl Encode for Uint64

const SIZE: DataSize

const ALIGNMENT: PageOffset = 8u16

impl Encode for Uuid

const SIZE: DataSize

const ALIGNMENT: PageOffset = 16u16

impl<T> Encode for Nullable<T>

where T: DataType,

const SIZE: DataSize = DataSize::Dynamic

const ALIGNMENT: PageOffset = 32u16