pub struct ColumnReaderImpl<T: DataType> { /* fields omitted */ }
Typed value reader for a particular primitive column.
Creates new column reader based on column descriptor and page reader.
Reads a batch of values of at most batch_size
.
This will try to read from the row group, and fills up at most batch_size
values
for def_levels
, rep_levels
and values
. It will stop either when the row group
is depleted or batch_size
values has been read, or there is no space in the input
slices (values/definition levels/repetition levels).
Note that in case the field being read is not required, values
could contain less
values than def_levels
. Also note that this will skip reading def / rep levels if
the field is required / not repeated, respectively.
If def_levels
or rep_levels
is None
, this will also skip reading the
respective levels. This is useful when the caller of this function knows in advance
that the field is required and non-repeated, therefore can avoid allocating memory
for the levels data. Note that if field has definition levels, but caller provides
None, there might be inconsistency between levels/values (see comments below).
Returns a tuple where the first element is the actual number of values read,
and the second element is the actual number of levels read.
🔬 This is a nightly-only experimental API. (try_from
)
The type returned in the event of a conversion error.
🔬 This is a nightly-only experimental API. (try_from
)
Immutably borrows from an owned value. Read more
🔬 This is a nightly-only experimental API. (get_type_id
)
this method will likely be replaced by an associated static
🔬 This is a nightly-only experimental API. (try_from
)
The type returned in the event of a conversion error.
🔬 This is a nightly-only experimental API. (try_from
)
Mutably borrows from an owned value. Read more
🔬 This is a nightly-only experimental API. (rustc_private
)
this crate is being loaded from the sysroot, an unstable location; did you mean to load this crate from crates.io via Cargo.toml
instead?
Create an error for a missing method specialization. Defaults to panicking with type, trait & method names. S
is the encoder/decoder state type, T
is the type being encoded/decoded, and the arguments are the names of the trait and method that should've been overridden. Read more
impl<T, U> TryInto for T where U: TryFrom<T>, | |
type Err = <U as TryFrom<T>>::Err