Struct Header 

pub struct Header { /* private fields */ }

A parsed header unit: an ordered list of content cards plus a side index for O(1) keyword lookup.

Order and duplicates are preserved exactly (commentary cards repeat, and record order is significant), so the model is a vector — never a map. The terminating END record is implicit and not stored as a card. Long-string values split across CONTINUE records are reassembled into a single value card on read and re-emitted as a canonical CONTINUE chain on write, so the round-trip preserves the logical model (not necessarily the original byte split).

Implementations

impl Header

pub fn parse(bytes: &[u8]) -> Result<Header>

Parse a header unit from its raw bytes (a whole number of 80-byte cards; the reader supplies block-aligned input). Stops at the END record.

pub fn get(&self, keyword: &str) -> Option<&Value>

The value of the first card with this keyword, if it is a valued card.

pub fn get_logical(&self, keyword: &str) -> Option<bool>

pub fn get_integer(&self, keyword: &str) -> Option<i64>

pub fn get_real(&self, keyword: &str) -> Option<f64>

pub fn get_text(&self, keyword: &str) -> Option<&str>

pub fn iter(&self) -> impl Iterator<Item = HeaderEntry<'_>>

Every stored record in file order, as HeaderEntry views — duplicates and order preserved (the whole point of the ordered model), so COMMENT/HISTORY runs and repeated keywords come through intact. The implicit END is not a record and is never yielded. For valued keywords only, filter on e.value: header.iter().filter_map(|e| Some((e.keyword, e.value?))).

pub fn bitpix(&self) -> Result<Bitpix>

BITPIX, mapped to the typed element kind.

pub fn naxis(&self) -> Result<usize>

NAXIS — the number of axes (0 means no data array).

pub fn axes(&self) -> Result<Vec<usize>>

The axis lengths NAXIS1..NAXIS{NAXIS}, in order.

pub fn scaling(&self) -> Scaling

The physical-value scaling (BSCALE/BZERO/BLANK) declared by this header.

pub fn wcs(&self, alt: Option<char>) -> Result<Wcs>

Parse the World Coordinate System (FITS §8) described by this header: the primary description (alt = None) or an alternate (alt = Some('A'..='Z')).

pub fn wcs_pixel_list( &self, columns: &[usize], alt: Option<char>, ) -> Result<Wcs>

WCS for a pixel-list table (§8.4.2), where the given columns hold the coordinate axes; alt selects the primary (None) or an alternate system.

pub fn wcs_array_column(&self, column: usize, alt: Option<char>) -> Result<Wcs>

WCS attached to a single array-valued table column (§8.4.1).

pub fn time(&self) -> FitsTime

The time-coordinate frame (FITS §9) parsed from this header — reference epoch/scale, units, and any time WCS axis.

pub fn obs_mjd(&self) -> Option<f64>

The observation Modified Julian Date — MJD-OBS, else DATE-OBS, else the JEPOCH/BEPOCH epoch, else None.

pub fn epoch(&self) -> Option<EpochTime>

The Julian (JEPOCH) or Besselian (BEPOCH) epoch keyword, if present.

pub fn time_bounds(&self) -> TimeBounds

The observation time bounds (start/end/duration, §9.2.3) from this header.

pub fn phase_axis(&self, axis: usize) -> Option<PhaseAxis>

The §9.6 'PHASE' axis parameters for WCS axis (1-based), if it is one.

pub fn new() -> Header

Create an empty header. Build it up with Header::set and friends.

pub fn set(&mut self, keyword: &str, value: impl Into<Value>) -> &mut Self

Insert a valued keyword, or replace the value of an existing one, keeping the keyword index in sync. Returns &mut self for chaining. The keyword must be a valid FITS keyword name (≤ 8 chars of A–Z, 0–9, -, _).

pub fn comment(&mut self, keyword: &str, text: &str) -> &mut Self

Attach (or replace) the inline comment of an existing valued keyword; a no-op if the keyword is absent.

pub fn push_comment(&mut self, text: &str) -> &mut Self

Append a COMMENT card.

pub fn push_history(&mut self, text: &str) -> &mut Self

Append a HISTORY card.

Trait Implementations

impl Clone for Header

fn clone(&self) -> Header

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Header

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

Formats the value using the given formatter.

impl Default for Header

fn default() -> Header

Returns the “default value” for a type.