Struct DataspaceMessage 

pub struct DataspaceMessage {
    pub class: DataspaceClass,
    pub dims: Vec<u64>,
    pub max_dims: Option<Vec<u64>>,
}

Dataspace message payload.

Fields

class: DataspaceClass

Which dataspace class this message describes.

dims: Vec<u64>

Current dimension sizes. Empty for Scalar and Null.

max_dims: Option<Vec<u64>>

Maximum dimension sizes; an entry of u64::MAX means unlimited.

None is upstream’s H5S_extent_t.max == NULL: the extent carries no maximum array at all, which is a different thing from a maximum that happens to equal the current dimensions. Only decoding a message with H5S_VALID_MAX clear produces it (H5Osdspace.c:188-194) — every extent the API builds is given one (H5S.c:1293-1299) — and it survives being rewritten, because H5S_read and H5S_write decode and re-encode the one extent (H5S.c:1100, H5S.c:1039) and the encoder raises the flag only for a non-null array (H5Osdspace.c:271-272).

Upstream reads the absent array as the current dimensions wherever a bound is reported (H5S_extent_get_dims, H5S.c:968-973), which is what the crate’s consumers do too; H5S_set_extent is the exception that treats it as no bound at all (H5S.c:1777).

Implementations

impl DataspaceMessage

pub fn scalar() -> Self

A scalar dataspace (rank 0, no max dims).

pub fn null() -> Self

The NULL dataspace: no elements at all. Unlike scalar, a dataset with this dataspace holds zero bytes of data.

pub fn simple(dims: &[u64]) -> Self

A simple dataspace with fixed dimensions (max == current). An empty dims yields a scalar dataspace, matching how upstream never emits a Simple-class dataspace at rank 0.

The maximum is filled in here, not at encode time, because that is where upstream fills it in: H5S_set_extent_simple allocates extent.max for every simple extent and copies the current dimensions into it when the caller named no maximum (H5S.c:1293-1299).

pub fn unlimited(current: &[u64]) -> Self

A simple dataspace where every dimension is unlimited.

pub fn is_null(&self) -> bool

Whether this is the NULL dataspace (no elements at all).

pub fn element_count(&self) -> Option<u64>

The number of elements in the extent (H5S_GET_EXTENT_NPOINTS): none for a null dataspace, one for a scalar, the product of the dimensions otherwise. None when that product does not fit in a u64.

pub fn encode(&self, ctx: &FormatContext) -> Vec<u8>

pub fn encode_for(&self, ctx: &FormatContext, format: ObjectFormat) -> Vec<u8>

Encode for a file of the given object format.

A version-1 dataspace differs only in its prefix: no type byte, and five reserved bytes where version 2 has one, so the header is 8 bytes rather than 4. The dimensions that follow are identical.

pub fn decode(buf: &[u8], ctx: &FormatContext) -> FormatResult<(Self, usize)>

Trait Implementations

impl Clone for DataspaceMessage

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for DataspaceMessage

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

Formats the value using the given formatter.

impl PartialEq for DataspaceMessage

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

Equality operator ==.

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

Inequality operator !=.

impl StructuralPartialEq for DataspaceMessage