Struct Overlay 

pub struct Overlay { /* private fields */ }

An update section under construction over an OverlayBase: which objects it holds, new ones numbered from the base’s first free number.

Implementations

impl Overlay

pub fn new(base: OverlayBase) -> Overlay

An empty update section over base, numbering new objects from its first free number.

pub fn set(&mut self, r: ObjRef, obj: Object)

Sets an object under its own number, whether new or a replacement of one already in the base. Raises the next free number past r when r was not already reserved, so a later reserve/put never collides with a caller-chosen number. A no-op for object number 0: it is already the free list’s own permanent head, represented by this section’s synthetic entry-0 row whenever any other object is freed, and a set row for it would collide with that row. Symmetric with Overlay::remove’s guard.

pub fn remove(&mut self, r: ObjRef)

Marks r free: the appended section’s cross-reference data chains it into entry 0’s free list, in whichever style the base uses. Its generation for reuse is r.gen advanced by one (saturating at 65535, the field’s own limit), per the classic table’s convention for a deleted entry’s row. A no-op for object number 0: it is already the free list’s own permanent head, represented by this section’s synthetic entry-0 row whenever any other object is freed.

pub fn reserve(&mut self) -> ObjRef

Allocates the next free object number without storing anything under it yet.

pub fn put(&mut self, obj: Object) -> ObjRef

Adds a new object under the next free number.

pub fn set_info(&mut self, r: ObjRef)

Registers the document information dictionary for the appended section’s trailer, overriding the base’s own.

pub fn is_empty(&self) -> bool

Whether nothing has been set or removed yet.

pub fn section(&self, start: u64) -> Result<Vec<u8>>

The appended section alone: every set object at start plus its position within this section, then a cross-reference section in the base’s style naming the base’s section as /Prev. Refused when no object has been set. A number recorded more than once (repeated set, or set and remove on the same reference) keeps only its last-recorded change, so the appended cross-reference data never carries two rows for one number.

Trait Implementations

impl Clone for Overlay

fn clone(&self) -> Overlay

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Overlay

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

Formats the value using the given formatter.