Struct `Directory`

pub struct Directory { /* private fields */ }

An Image File Directory (IFD).

A directory is a map of Tags to Values. The values are stored anywhere in the file, with the directory containing the offsets and length of the associated values for each tag present in the directory.

A directory can be created with with Decoder::read_directory or as an empty directory to be extended with entries. A directory may be used with Decoder::read_directory_tags to read the values associated with tags from an underlying file.

Implementations

`impl Directory`

fn empty() -> Self

Create a directory in an initial state without entries. Note that an empty directory can not be encoded in a file, it must contain at least one entry.

fn get(&self, tag: Tag) -> Option<&Entry>

Retrieve the value associated with a tag.

fn contains(&self, tag: Tag) -> bool

Check if the directory contains a specified tag.

fn iter(&self) -> impl Iterator<Item = (Tag, &Entry)> + '_

Iterate over all known and unknown tags in this directory.

fn extend(&mut self, iter: impl IntoIterator<Item = (Tag, Entry)>)

Insert additional entries into the directory.

Note that a directory can contain at most u16::MAX values. There may be one entry that does not fit into the directory. This entry is silently ignored (please check Self::len to detect the condition). Providing a tag multiple times or a tag that already exists within this directory overwrites the entry.

fn len(&self) -> usize

Get the number of entries.

fn is_empty(&self) -> bool

Check if there are any entries in this directory. Note that an empty directory can not be encoded in the file, it must contain at least one entry.

fn next(&self) -> Option<IfdPointer>

Get the pointer to the next IFD, if it was defined.

fn set_next(&mut self, next: Option<IfdPointer>)

Trait Implementations

`impl Debug for Directory`

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

`impl FromIterator<(Tag, Entry)> for Directory`

fn from_iter<T: IntoIterator<Item = (Tag, Entry)>>(iter: T) -> Self

Auto Trait Implementations

`impl Freeze for Directory`

`impl RefUnwindSafe for Directory`

`impl Send for Directory`

`impl Sync for Directory`

`impl Unpin for Directory`

`impl UnsafeUnpin for Directory`

`impl UnwindSafe for Directory`

Blanket Implementations

`impl<ST, DT> CastableFrom<ST, Initialized, Initialized> for Directory where ST: ?Sized, DT: ?Sized,`

`impl<ST, DT> CastableFrom<ST, Uninit, Uninit> for Directory where ST: ?Sized, DT: ?Sized,`

`impl<T> Any for Directory where T: 'static + ?Sized,`

fn type_id(&self) -> TypeId

`impl<T> Borrow<T> for Directory where T: ?Sized,`

fn borrow(&self) -> &T

`impl<T> BorrowMut<T> for Directory where T: ?Sized,`

fn borrow_mut(&mut self) -> &mut T

`impl<T> From<T> for Directory`

fn from(t: T) -> T: Returns the argument unchanged.

`impl<T> Read<Exclusive, BecauseExclusive> for Directory where T: ?Sized,`

`impl<T, U> Into for Directory where U: From<T>,`

fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of [From]<T> for U chooses to do.

`impl<T, U> TryFrom for Directory where U: Into<T>,`

type Error = never;
fn try_from(value: U) -> Result<T, never>

`impl<T, U> TryInto for Directory where U: TryFrom<T>,`

type Error = >::Error;
fn try_into(self) -> Result<U, >::Error>