Coverage for python/lsst/images/fits/_output_archive.py: 72%
228 statements
« prev ^ index » next coverage.py v7.14.3, created at 2026-06-29 22:40 +0000
1# This file is part of lsst-images.
2#
3# Developed for the LSST Data Management System.
4# This product includes software developed by the LSST Project
5# (https://www.lsst.org).
6# See the COPYRIGHT file at the top-level directory of this distribution
7# for details of code ownership.
8#
9# Use of this source code is governed by a 3-clause BSD-style
10# license that can be found in the LICENSE file.
12from __future__ import annotations
14__all__ = ("FitsOutputArchive", "write")
16import dataclasses
17from collections.abc import Callable, Hashable, Iterator, Mapping
18from contextlib import contextmanager
19from typing import Any, Self
21import astropy.io.fits
22import astropy.table
23import astropy.time
24import numpy as np
25import pydantic
27from .._transforms import FrameSet
28from ..serialization import (
29 ArchiveTree,
30 ArrayReferenceModel,
31 ButlerInfo,
32 MetadataValue,
33 NestedOutputArchive,
34 NumberType,
35 OutputArchive,
36 TableColumnModel,
37 TableModel,
38 no_header_updates,
39)
40from ._common import (
41 JSON_COLUMN,
42 JSON_EXTNAME,
43 ExtensionHDU,
44 ExtensionKey,
45 FitsCompressionOptions,
46 FitsOpaqueMetadata,
47 PointerModel,
48 suppress_fits_card_warnings,
49)
51_FITS_FORMAT_VERSION = 1
52"""Container layout version for files written by `FitsOutputArchive`.
54Bumps when the on-disk FITS layout (HDU placement, INDX/JSON keyword schema)
55changes. Independent of any data-model ``SCHEMA_VERSION``.
56"""
59def _set_creation_date(header: astropy.io.fits.Header) -> None:
60 """Record the current UTC time in the ``DATE`` card of a FITS header.
62 Parameters
63 ----------
64 header
65 Header to modify in place.
67 Notes
68 -----
69 The FITS standard requires every HDU to record the UTC date and time its
70 header was created via a ``DATE`` card in ``YYYY-MM-DDThh:mm:ss[.sss]``
71 form. Any pre-existing ``DATE`` card (such as one preserved from an input
72 archive) is overwritten in place so the value reflects this write.
73 """
74 header.set("DATE", astropy.time.Time.now().fits, "UTC date this HDU was written.")
77def write(
78 obj: Any,
79 path: str,
80 compression_options: Mapping[str, FitsCompressionOptions | None] | None = None,
81 update_header: Callable[[astropy.io.fits.Header], None] = no_header_updates,
82 compression_seed: int | None = None,
83 metadata: dict[str, MetadataValue] | None = None,
84 butler_info: ButlerInfo | None = None,
85) -> Any:
86 """Write an object with a ``serialize`` method to a FITS file.
88 Parameters
89 ----------
90 obj
91 Object with a ``serialize`` method to write.
92 path
93 Name of the file to write to. Must not already exist.
94 compression_options
95 Options for how to compress the FITS file, keyed by the name of
96 the attribute (with JSON pointer ``/`` separators for nested
97 attributes).
98 update_header
99 A callback that will be given the primary HDU FITS header and an
100 opportunity to modify it.
101 compression_seed
102 A FITS tile compression seed to use whenever the configured
103 compression seed is `None` or (for backwards compatibility) ``0``.
104 This value is then incremented every time it is used.
105 metadata
106 Additional metadata to save with the object. This will override any
107 flexible metadata carried by the object itself with the same keys.
108 butler_info
109 Butler information to store in the file.
111 Returns
112 -------
113 `.serialization.ArchiveTree`
114 The serialized representation of the object.
115 """
116 opaque_metadata = getattr(obj, "_opaque_metadata", None)
117 name = getattr(obj, "_archive_default_name", None)
118 with FitsOutputArchive.open(
119 path,
120 compression_options=compression_options,
121 opaque_metadata=opaque_metadata,
122 update_header=update_header,
123 compression_seed=compression_seed,
124 ) as archive:
125 tree = archive.serialize_direct(name, obj.serialize) if name is not None else obj.serialize(archive)
126 if metadata is not None: 126 ↛ 127line 126 didn't jump to line 127 because the condition on line 126 was never true
127 tree.metadata.update(metadata)
128 if butler_info is not None:
129 tree.butler_info = butler_info
130 archive.add_tree(tree)
131 return tree
134class FitsOutputArchive(OutputArchive[PointerModel]):
135 """An implementation of the `.serialization.OutputArchive` interface that
136 writes to FITS files.
138 Instances of this class should only be constructed via the `open`
139 context manager.
141 Parameters
142 ----------
143 hdu_list
144 HDU list that the archive writes its HDUs into.
145 compression_options
146 Options for how to compress the FITS file, keyed by the name of
147 the attribute (with JSON pointer ``/`` separators for nested
148 attributes).
149 opaque_metadata
150 Opaque metadata to carry through from the object being written.
151 compression_seed
152 A FITS tile compression seed to use whenever the configured
153 compression seed is `None` or (for backwards compatibility)
154 ``0``.
155 """
157 def __init__(
158 self,
159 hdu_list: astropy.io.fits.HDUList,
160 compression_options: Mapping[str, FitsCompressionOptions | None] | None = None,
161 opaque_metadata: Any = None,
162 compression_seed: int | None = None,
163 ) -> None:
164 super().__init__()
165 # JSON blobs for objects we've saved as pointers:
166 self._pointer_targets: list[bytes] = []
167 # Mapping from user provided key (e.g. id(some object)) to a table
168 # pointer to where we actually saved it:
169 self._pointers_by_key: dict[Hashable, PointerModel] = {}
170 self._hdu_list = hdu_list
171 self._primary_hdu = astropy.io.fits.PrimaryHDU()
172 self._primary_hdu.header.set("FMTVER", _FITS_FORMAT_VERSION, "FITS container layout version.")
173 self._primary_hdu.header.set("INDXADDR", 0, "Offset in bytes to the HDU index.")
174 self._primary_hdu.header.set("INDXSIZE", 0, "Size of the HDU index.")
175 self._primary_hdu.header.set("JSONADDR", 0, "Offset in bytes to the JSON tree HDU.")
176 self._primary_hdu.header.set("JSONSIZE", 0, "Size of the JSON tree HDU.")
177 self._compression_options = dict(compression_options) if compression_options is not None else {}
178 self._compression_seed = compression_seed
179 self._opaque_metadata = (
180 opaque_metadata if isinstance(opaque_metadata, FitsOpaqueMetadata) else FitsOpaqueMetadata()
181 )
182 if (opaque_primary_header := self._opaque_metadata.headers.get(ExtensionKey())) is not None:
183 self._primary_hdu.header.extend(opaque_primary_header)
184 self._hdu_list.append(self._primary_hdu)
185 self._json_hdu_added: bool = False
186 self._frame_sets: list[tuple[FrameSet, PointerModel]] = []
188 @classmethod
189 @contextmanager
190 def open(
191 cls,
192 filename: str,
193 compression_options: Mapping[str, FitsCompressionOptions | None] | None = None,
194 opaque_metadata: Any = None,
195 update_header: Callable[[astropy.io.fits.Header], None] = no_header_updates,
196 compression_seed: int | None = None,
197 ) -> Iterator[Self]:
198 """Create an output archive that writes to the given file.
200 Parameters
201 ----------
202 filename
203 Name of the file to write to. Must not already exist.
204 compression_options
205 Options for how to compress the FITS file, keyed by the name of
206 the attribute (with JSON pointer ``/`` separators for nested
207 attributes).
208 opaque_metadata
209 Metadata read from an input archive along with the object being
210 written now. Ignored if the metadata is not from a FITS archive.
211 update_header
212 A callback that will be given the primary HDU FITS header and an
213 opportunity to modify it.
214 compression_seed
215 A FITS tile compression seed to use whenever the configured
216 compression seed is `None` or (for backwards compatibility) ``0``.
217 This value is then incremented every time it is used.
219 Returns
220 -------
221 `contextlib.AbstractContextManager` [`FitsOutputArchive`]
222 A context manager that returns a `FitsOutputArchive` when entered.
223 """
224 # Astropy auto-fixes over-long keywords (HIERARCH) and comments
225 # (truncation) as cards are created and written, but doesn't honor its
226 # own output_verify option for these warnings, so we filter them out
227 # across the write of the main HDUs.
228 with suppress_fits_card_warnings(), astropy.io.fits.open(filename, mode="append") as hdu_list:
229 if hdu_list: 229 ↛ 230line 229 didn't jump to line 230 because the condition on line 229 was never true
230 raise OSError(f"File {filename!r} already exists.")
231 archive = cls(hdu_list, compression_options, opaque_metadata, compression_seed=compression_seed)
232 update_header(hdu_list[0].header)
233 # Set the creation date after update_header so a caller's callback
234 # cannot leave a stale DATE in the primary header; this card must
235 # always record the time of this write.
236 _set_creation_date(hdu_list[0].header)
237 yield archive
238 if not archive._json_hdu_added: 238 ↛ 239line 238 didn't jump to line 239 because the condition on line 238 was never true
239 raise RuntimeError("Write context exited without 'add_tree' being called.")
240 hdu_list.flush()
241 # This multi-open dance is necessary to get Astropy to tell us the
242 # byte addresses of the HDUs. Hopefully we can get an upstream change
243 # make this unnecessary at some point.
244 with astropy.io.fits.open(filename, mode="readonly", disable_image_compression=True) as hdu_list:
245 index_hdu = cls._make_index_table(hdu_list)
246 with astropy.io.fits.open(filename, mode="append") as hdu_list:
247 hdu_list.append(index_hdu)
248 json_bytes = _HDUBytes.from_index_row(index_hdu.data[-1])
249 index_bytes = _HDUBytes.from_write_hdu(index_hdu)
250 # Update the primary HDU with the address and size of the index and
251 # JSON HDUs, and rewrite just that. We do this write manually, since
252 # astropy's docs on its 'update' mode are scarce and it's not obvious
253 # whether we can guarantee it won't rewrite the whole file if we edit
254 # the primary header.
255 archive._primary_hdu.header["INDXADDR"] = index_bytes.header_address
256 archive._primary_hdu.header["INDXSIZE"] = index_bytes.size
257 archive._primary_hdu.header["JSONADDR"] = json_bytes.header_address
258 archive._primary_hdu.header["JSONSIZE"] = json_bytes.size
259 with open(filename, "r+b") as stream:
260 stream.write(archive._primary_hdu.header.tostring().encode())
262 def serialize_direct[T: pydantic.BaseModel | None](
263 self, name: str, serializer: Callable[[OutputArchive[PointerModel]], T]
264 ) -> T:
265 nested = NestedOutputArchive[PointerModel](name, self)
266 return serializer(nested)
268 def serialize_pointer[T: ArchiveTree](
269 self, name: str, serializer: Callable[[OutputArchive[PointerModel]], T], key: Hashable
270 ) -> PointerModel:
271 if (pointer := self._pointers_by_key.get(key)) is not None: 271 ↛ 272line 271 didn't jump to line 272 because the condition on line 271 was never true
272 return pointer
273 # Rooting the nested archive at "" follows the NestedOutputArchive
274 # convention that root paths are absolute, but serialize_direct roots
275 # at the bare name, so an array written by a pointer target would get
276 # a "/"-prefixed EXTNAME (e.g. "/DATA"). No serializer currently
277 # writes arrays inside pointer targets; if one ever does, consider
278 # rooting at ``name`` instead, as the NDF backend does.
279 model = self.serialize_direct("", serializer)
280 json_bytes = model.model_dump_json().encode()
281 self._pointer_targets.append(json_bytes)
282 pointer = PointerModel(
283 column=TableColumnModel(
284 name=JSON_COLUMN,
285 data=ArrayReferenceModel(
286 source=f"fits:{JSON_EXTNAME}[1]",
287 shape=[len(json_bytes)],
288 datatype=NumberType.uint8,
289 ),
290 ),
291 row=len(self._pointer_targets),
292 )
293 self._pointers_by_key[key] = pointer
294 return pointer
296 def serialize_frame_set[T: ArchiveTree](
297 self, name: str, frame_set: FrameSet, serializer: Callable[[OutputArchive], T], key: Hashable
298 ) -> PointerModel:
299 # Docstring inherited.
300 pointer = self.serialize_pointer(name, serializer, key)
301 self._frame_sets.append((frame_set, pointer))
302 return pointer
304 def iter_frame_sets(self) -> Iterator[tuple[FrameSet, PointerModel]]:
305 return iter(self._frame_sets)
307 def add_array(
308 self,
309 array: np.ndarray,
310 *,
311 name: str | None = None,
312 update_header: Callable[[astropy.io.fits.Header], None] = no_header_updates,
313 tile_shape: tuple[int, ...] | None = None,
314 options_name: str | None = None,
315 ) -> ArrayReferenceModel:
316 if name is None: 316 ↛ 317line 316 didn't jump to line 317 because the condition on line 316 was never true
317 raise RuntimeError("Cannot save array with name=None unless it is nested.")
318 name, version = self._register_name(name)
319 extname = name.upper()
320 hdu = self._opaque_metadata.maybe_use_precompressed(extname)
321 if hdu is None: 321 ↛ 328line 321 didn't jump to line 328 because the condition on line 321 was always true
322 if options_name is None: 322 ↛ 324line 322 didn't jump to line 324 because the condition on line 322 was always true
323 options_name = name
324 if (compression_options := self._get_compression_options(options_name, tile_shape)) is not None: 324 ↛ 327line 324 didn't jump to line 327 because the condition on line 324 was always true
325 hdu = compression_options.make_hdu(array, name=extname)
326 else:
327 hdu = astropy.io.fits.ImageHDU(array, name=extname)
328 key = self._add_hdu(hdu, version, update_header)
329 return ArrayReferenceModel(
330 source=str(key),
331 shape=list(array.shape),
332 datatype=NumberType.from_numpy(array.dtype),
333 )
335 def add_table(
336 self,
337 table: astropy.table.Table,
338 *,
339 name: str | None = None,
340 update_header: Callable[[astropy.io.fits.Header], None] = no_header_updates,
341 ) -> TableModel:
342 if name is None:
343 raise RuntimeError("Cannot save table with name=None unless it is nested.")
344 name, version = self._register_name(name)
345 extname = name.upper()
346 hdu: astropy.io.fits.BinTableHDU = astropy.io.fits.table_to_hdu(table, name=extname)
347 # Extract column information directly from the input array, not the
348 # data in the binary table HDU, because we want to assume as little as
349 # possible about where Astropy does uint -> TZERO stuff.
350 columns = TableColumnModel.from_table(table)
351 key = self._add_hdu(hdu, version, update_header)
352 for n, c in enumerate(columns, start=1):
353 assert isinstance(c.data, ArrayReferenceModel)
354 c.data.source = f"{key}[{n}]"
355 return TableModel(columns=columns, meta=table.meta)
357 def add_structured_array(
358 self,
359 array: np.ndarray,
360 *,
361 name: str | None = None,
362 units: Mapping[str, astropy.units.Unit] | None = None,
363 descriptions: Mapping[str, str] | None = None,
364 update_header: Callable[[astropy.io.fits.Header], None] = no_header_updates,
365 ) -> TableModel:
366 if name is None:
367 raise RuntimeError("Cannot save structured array with name=None unless it is nested.")
368 name, version = self._register_name(name)
369 extname = name.upper()
370 # Extract column information directly from the input array, not the
371 # data in the binary table HDU, because we want to assume as little as
372 # possible about where Astropy does uint -> TZERO stuff.
373 columns = TableColumnModel.from_record_dtype(array.dtype)
374 hdu = astropy.io.fits.BinTableHDU(array, name=extname)
375 if units is not None:
376 for c in columns:
377 c.unit = units.get(c.name)
378 if descriptions is not None:
379 for c in columns:
380 c.description = descriptions.get(c.name, "")
381 key = self._add_hdu(hdu, version, update_header)
382 for n, c in enumerate(columns, start=1):
383 assert isinstance(c.data, ArrayReferenceModel)
384 c.data.source = f"{key}[{n}]"
385 return TableModel(columns=columns)
387 def _add_hdu(
388 self,
389 hdu: astropy.io.fits.ImageHDU | astropy.io.fits.CompImageHDU | astropy.io.fits.BinTableHDU,
390 version: int,
391 update_header: Callable[[astropy.io.fits.Header], None] = no_header_updates,
392 ) -> ExtensionKey:
393 key = ExtensionKey(hdu.name, version)
394 key.check()
395 if version > 1:
396 hdu.header["EXTVER"] = version
397 update_header(hdu.header)
398 if (opaque_headers := self._opaque_metadata.headers.get(key)) is not None:
399 hdu.header.extend(opaque_headers)
400 _set_creation_date(hdu.header)
401 self._hdu_list.append(hdu)
402 return key
404 def add_tree(self, tree: ArchiveTree) -> None:
405 """Write the JSON tree to the archive.
407 This method must be called exactly once, just before the `open` context
408 is exited.
410 Parameters
411 ----------
412 tree
413 Pydantic model that represents the tree.
414 """
415 self._primary_hdu.header.set("DATAMODL", tree.schema_url, "Schema URL.")
416 json_hdu = astropy.io.fits.BinTableHDU.from_columns(
417 [astropy.io.fits.Column(JSON_COLUMN, "PB")],
418 nrows=len(self._pointer_targets) + 1,
419 name=JSON_EXTNAME,
420 )
421 json_hdu.data[0][JSON_COLUMN] = np.frombuffer(tree.model_dump_json().encode(), dtype=np.byte)
422 for n, json_target_data in enumerate(self._pointer_targets):
423 json_hdu.data[n + 1][JSON_COLUMN] = np.frombuffer(json_target_data, dtype=np.byte)
424 _set_creation_date(json_hdu.header)
425 self._hdu_list.append(json_hdu)
426 self._json_hdu_added = True
428 def _get_compression_options(
429 self, name: str, tile_shape: tuple[int, ...] | None
430 ) -> FitsCompressionOptions | None:
431 result = self._compression_options.get(name, FitsCompressionOptions.DEFAULT)
432 if result is None: 432 ↛ 433line 432 didn't jump to line 433 because the condition on line 432 was never true
433 return result
434 if tile_shape is not None and result.tile_shape is None: 434 ↛ 435line 434 didn't jump to line 435 because the condition on line 434 was never true
435 result = result.model_copy(update={"tile_shape": tile_shape})
436 if result.quantization is None:
437 return result
438 if self._compression_seed is not None and not result.quantization.seed: 438 ↛ 449line 438 didn't jump to line 449 because the condition on line 438 was always true
439 result = result.model_copy(
440 update={
441 "quantization": result.quantization.model_copy(update={"seed": self._compression_seed})
442 }
443 )
444 self._compression_seed += 1
445 if self._compression_seed > 10000: 445 ↛ 446line 445 didn't jump to line 446 because the condition on line 445 was never true
446 self._compression_seed = 1
447 # MyPy can tell that result.quantization is not None in the 'if', but
448 # forgets that by this 'else':
449 elif result.quantization.seed is None: # type: ignore[union-attr]
450 raise RuntimeError("No quantization seed provided.")
451 return result
453 @staticmethod
454 def _make_index_table(hdu_list: astropy.io.fits.HDUList) -> astropy.io.fits.BinTableHDU:
455 # We use a fixed-length string for the EXTNAME column; it might be
456 # better to use a variable-length array, but I have not been able to
457 # figure out how to get astropy to accept a string for the the
458 # character (TFORM='A') variant of that. And that's only better if the
459 # EXTNAMEs get super long, which is not likely (but maybe something to
460 # guard against).
461 max_name_size = max(len(hdu.header.get("EXTNAME", "")) for hdu in hdu_list)
462 # Attach the ZIMAGE values as a boolean array on the Column itself.
463 # Astropy only fills a logical column's raw bytes with 'F' as the
464 # default (rather than NULL, 0x00) when the bool array is present at
465 # construction; assigning False element-wise after construction leaves
466 # the byte as NULL under Astropy 8.0.0, which warns on every read.
467 # Should be fixed in v8.0.1.
468 # See https://github.com/astropy/astropy/pull/19939
469 # but pre-allocating the entire column works in v7 and v8.
470 zimage = np.array([hdu.header.get("ZIMAGE", False) for hdu in hdu_list], dtype=bool)
471 index_hdu = astropy.io.fits.BinTableHDU.from_columns(
472 [
473 astropy.io.fits.Column("EXTNAME", f"A{max_name_size}"),
474 astropy.io.fits.Column("EXTVER", "J"),
475 astropy.io.fits.Column("XTENSION", "A8"),
476 astropy.io.fits.Column("ZIMAGE", "L", array=zimage),
477 ]
478 + _HDUBytes.get_index_hdu_columns(),
479 nrows=len(hdu_list),
480 name="INDEX",
481 )
482 hdu: ExtensionHDU | astropy.io.fits.PrimaryHDU
483 for n, hdu in enumerate(hdu_list):
484 index_hdu.data[n]["EXTNAME"] = hdu.header.get("EXTNAME", "")
485 index_hdu.data[n]["EXTVER"] = hdu.header.get("EXTVER", 1)
486 index_hdu.data[n]["XTENSION"] = hdu.header.get("XTENSION", "IMAGE")
487 bytes = _HDUBytes.from_read_hdu(hdu)
488 bytes.update_index_row(index_hdu.data[n])
489 _set_creation_date(index_hdu.header)
490 return index_hdu
493@dataclasses.dataclass
494class _HDUBytes:
495 """A struct that records the byte offsets into a FITS HDU."""
497 @classmethod
498 def from_write_hdu(cls, hdu: astropy.io.fits.PrimaryHDU | ExtensionHDU) -> Self:
499 """Construct from an Astropy HDU instance that has just been written.
501 Parameters
502 ----------
503 hdu
504 An Astropy HDU object.
506 Returns
507 -------
508 hdu_bytes
509 Struct with byte offsets.
511 Notes
512 -----
513 This method relies on internal Astropy attributes and does not work on
514 CompImageHDU objects.
515 """
516 # This is implemented by accessing private Astropy attributes because
517 # it turns out that's much more reliable than the public fileinfo()
518 # method, which seems to always return a dict with `None` entries or
519 # raise; it looks buggy, but docs are scarce enough that it's not clear
520 # what the right behavior is supposed to be.
521 if (header_address := getattr(hdu, "_header_offset", None)) is None: 521 ↛ 522line 521 didn't jump to line 522 because the condition on line 521 was never true
522 raise RuntimeError("Failed to get Astropy's _header_offset.")
523 if (data_address := getattr(hdu, "_data_offset", None)) is None: 523 ↛ 524line 523 didn't jump to line 524 because the condition on line 523 was never true
524 raise RuntimeError("Failed to get Astropy's _data_offset.")
525 if (data_size := getattr(hdu, "_data_size", None)) is None: 525 ↛ 526line 525 didn't jump to line 526 because the condition on line 525 was never true
526 raise RuntimeError("Failed to get Astropy's _data_size.")
527 return cls(header_address, data_address, data_size)
529 @classmethod
530 def from_read_hdu(cls, hdu: astropy.io.fits.PrimaryHDU | ExtensionHDU) -> Self:
531 """Construct from an Astropy HDU instance that has just been read.
533 Parameters
534 ----------
535 hdu
536 An Astropy HDU object.
538 Returns
539 -------
540 hdu_bytes
541 Struct with byte offsets.
542 """
543 info = hdu.fileinfo()
544 header_address = info["hdrLoc"]
545 data_address = info["datLoc"]
546 data_size = info["datSpan"]
547 return cls(header_address, data_address, data_size)
549 @classmethod
550 def from_index_row(cls, row: np.void) -> Self:
551 """Construct from a row of the index HDU.
553 Parameters
554 ----------
555 row
556 A Numpy struct-like scalar.
558 Returns
559 -------
560 hdu_bytes
561 Struct with byte offsets.
562 """
563 return cls(
564 header_address=int(row["HDRADDR"]),
565 data_address=int(row["DATADDR"]),
566 data_size=int(row["DATSIZE"]),
567 )
569 @staticmethod
570 def get_index_hdu_columns() -> list[astropy.io.fits.Column]:
571 """Return the definitions of the columns this class gets and sets
572 from the index HDU.
574 Returns
575 -------
576 columns
577 A `list` of `astropy.io.fits.Column` objects that represent the
578 header address, data address, and data size.
579 """
580 return [
581 astropy.io.fits.Column("HDRADDR", "K"),
582 astropy.io.fits.Column("DATADDR", "K"),
583 astropy.io.fits.Column("DATSIZE", "K"),
584 ]
586 header_address: int
587 """Offset from the beginning of the start of the file to the header of this
588 HDU, in bytes.
589 """
591 data_address: int
592 """Offset from the beginning of the start of the file to the data section
593 of this HDU, in bytes.
594 """
596 data_size: int
597 """Size of the data section in bytes."""
599 @property
600 def header_size(self) -> int:
601 """Size of the header in bytes."""
602 return self.data_address - self.header_address
604 @property
605 def end_address(self) -> int:
606 """Offset in bytes from the start of the file to the end of the HDU."""
607 return self.data_address + self.data_size
609 @property
610 def size(self) -> int:
611 """Total size of this HDU in bytes."""
612 return self.data_size + self.data_address - self.header_address
614 def update_index_row(self, row: np.void) -> None:
615 """Set the values of a row of the index HDU from this strut.
617 Parameters
618 ----------
619 row
620 A Numpy struct-like scalar to modify in place.
621 """
622 row["HDRADDR"] = self.header_address
623 row["DATADDR"] = self.data_address
624 row["DATSIZE"] = self.data_size