Crate fits_header

Expand description

§fits-header

A pure-Rust, MSVC-safe library for reading and writing the header of a FITS file.

It reads a header unit into an ordered Header of records, retaining every card so untouched cards serialize byte-for-byte and only created or modified cards are re-rendered. Access is strict and keyword-oriented: Header::get and friends take a Key that is either a bare name (unique-or-FitsError::AmbiguousKeyword) or (name, occurrence). Values read through a generic FromCard and write through IntoValue; batch edits are atomic; long strings use the CONTINUE convention.

use fits_header::Header;

let mut h = Header::new();
h.set("OBJECT", "M31").unwrap();
h.set("EXPTIME", 120.0).unwrap();
assert_eq!(h.get::<f64>("EXPTIME").unwrap(), Some(120.0));

// The header block only — creating a file means appending your own pixel data after
// this; editing an existing file means Header::update_file, which preserves it.
let bytes = h.to_header_bytes();
assert_eq!(bytes.len() % fits_header::BLOCK_LEN, 0);

§Design

Pure Rust, no C or system libraries; builds with the MSVC toolchain.
An untouched card (and untouched long-string run) re-emits identical bytes.
Ambiguous keyword access errors instead of guessing.

§Features

serde (off) — derive Serialize/Deserialize on the public types.

Structs§

Fixed: Write a float with a fixed number of decimal places.
Header: An ordered FITS header unit: Records in appearance order, with strict keyword access (via Key) and CRUD.
Literal: Write a literal token verbatim (numeric text a vendor supplied, or a value you don’t want reformatted).
Record: One header card. Carries its parsed RecordKind plus, when parsed and unmodified, the original bytes of its physical card(s) so it can be serialized verbatim.
Sci: Write a float in scientific notation with N significant digits (uppercase E).

Enums§

FitsError: Errors from validated header mutations, ambiguous lookups, and oversized standalone serialization.
Key: Selects a record by keyword.
RecordKind: The semantic content of a Record.
Value: A value card’s payload.

Constants§

BLOCK_LEN: Bytes per FITS block (36 cards).
CARD_LEN: Bytes per header card.

Traits§

FromCard: Convert a record’s value into a Rust type. The extension point behind Header::get.
IntoValue: Convert a Rust value into a Value. The extension point behind Header::set / append.

Functions§

format_datetime: Format a date/time back to the FITS civil form (YYYY-MM-DDThh:mm:ss[.fff]), dropping a zero sub-second part.
parseDeprecated: Deprecated free-function alias for Header::parse; use that instead.
parse_datetime: Parse a FITS civil date/time (YYYY-MM-DD[Thh:mm:ss[.fff]]), timezone-naive.
parse_f64: Parse a float, accepting the Fortran D exponent (1.5D3).
parse_i64: Parse an integer, accepting decimal-form integers ("20.0" → 20).

Type Aliases§

Result: A Result whose error is always FitsError.