Coverage for python/lsst/images/fits/_output_archive.py: 72%
228 statements
« prev ^ index » next coverage.py v7.14.3, created at 2026-06-24 08:46 +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 path
91 Name of the file to write to. Must not already exist.
92 compression_options
93 Options for how to compress the FITS file, keyed by the name of
94 the attribute (with JSON pointer ``/`` separators for nested
95 attributes).
96 update_header
97 A callback that will be given the primary HDU FITS header and an
98 opportunity to modify it.
99 compression_seed
100 A FITS tile compression seed to use whenever the configured
101 compression seed is `None` or (for backwards compatibility) ``0``.
102 This value is then incremented every time it is used.
103 metadata
104 Additional metadata to save with the object. This will override any
105 flexible metadata carried by the object itself with the same keys.
106 butler_info
107 Butler information to store in the file.
109 Returns
110 -------
111 `.serialization.ArchiveTree`
112 The serialized representation of the object.
113 """
114 opaque_metadata = getattr(obj, "_opaque_metadata", None)
115 name = getattr(obj, "_archive_default_name", None)
116 with FitsOutputArchive.open(
117 path,
118 compression_options=compression_options,
119 opaque_metadata=opaque_metadata,
120 update_header=update_header,
121 compression_seed=compression_seed,
122 ) as archive:
123 tree = archive.serialize_direct(name, obj.serialize) if name is not None else obj.serialize(archive)
124 if metadata is not None: 124 ↛ 125line 124 didn't jump to line 125 because the condition on line 124 was never true
125 tree.metadata.update(metadata)
126 if butler_info is not None:
127 tree.butler_info = butler_info
128 archive.add_tree(tree)
129 return tree
132class FitsOutputArchive(OutputArchive[PointerModel]):
133 """An implementation of the `.serialization.OutputArchive` interface that
134 writes to FITS files.
136 Instances of this class should only be constructed via the `open`
137 context manager.
138 """
140 def __init__(
141 self,
142 hdu_list: astropy.io.fits.HDUList,
143 compression_options: Mapping[str, FitsCompressionOptions | None] | None = None,
144 opaque_metadata: Any = None,
145 compression_seed: int | None = None,
146 ) -> None:
147 super().__init__()
148 # JSON blobs for objects we've saved as pointers:
149 self._pointer_targets: list[bytes] = []
150 # Mapping from user provided key (e.g. id(some object)) to a table
151 # pointer to where we actually saved it:
152 self._pointers_by_key: dict[Hashable, PointerModel] = {}
153 self._hdu_list = hdu_list
154 self._primary_hdu = astropy.io.fits.PrimaryHDU()
155 self._primary_hdu.header.set("FMTVER", _FITS_FORMAT_VERSION, "FITS container layout version.")
156 self._primary_hdu.header.set("INDXADDR", 0, "Offset in bytes to the HDU index.")
157 self._primary_hdu.header.set("INDXSIZE", 0, "Size of the HDU index.")
158 self._primary_hdu.header.set("JSONADDR", 0, "Offset in bytes to the JSON tree HDU.")
159 self._primary_hdu.header.set("JSONSIZE", 0, "Size of the JSON tree HDU.")
160 self._compression_options = dict(compression_options) if compression_options is not None else {}
161 self._compression_seed = compression_seed
162 self._opaque_metadata = (
163 opaque_metadata if isinstance(opaque_metadata, FitsOpaqueMetadata) else FitsOpaqueMetadata()
164 )
165 if (opaque_primary_header := self._opaque_metadata.headers.get(ExtensionKey())) is not None:
166 self._primary_hdu.header.extend(opaque_primary_header)
167 self._hdu_list.append(self._primary_hdu)
168 self._json_hdu_added: bool = False
169 self._frame_sets: list[tuple[FrameSet, PointerModel]] = []
171 @classmethod
172 @contextmanager
173 def open(
174 cls,
175 filename: str,
176 compression_options: Mapping[str, FitsCompressionOptions | None] | None = None,
177 opaque_metadata: Any = None,
178 update_header: Callable[[astropy.io.fits.Header], None] = no_header_updates,
179 compression_seed: int | None = None,
180 ) -> Iterator[Self]:
181 """Create an output archive that writes to the given file.
183 Parameters
184 ----------
185 filename
186 Name of the file to write to. Must not already exist.
187 compression_options
188 Options for how to compress the FITS file, keyed by the name of
189 the attribute (with JSON pointer ``/`` separators for nested
190 attributes).
191 opaque_metadata
192 Metadata read from an input archive along with the object being
193 written now. Ignored if the metadata is not from a FITS archive.
194 update_header
195 A callback that will be given the primary HDU FITS header and an
196 opportunity to modify it.
197 compression_seed
198 A FITS tile compression seed to use whenever the configured
199 compression seed is `None` or (for backwards compatibility) ``0``.
200 This value is then incremented every time it is used.
202 Returns
203 -------
204 `contextlib.AbstractContextManager` [`FitsOutputArchive`]
205 A context manager that returns a `FitsOutputArchive` when entered.
206 """
207 # Astropy auto-fixes over-long keywords (HIERARCH) and comments
208 # (truncation) as cards are created and written, but doesn't honor its
209 # own output_verify option for these warnings, so we filter them out
210 # across the write of the main HDUs.
211 with suppress_fits_card_warnings(), astropy.io.fits.open(filename, mode="append") as hdu_list:
212 if hdu_list: 212 ↛ 213line 212 didn't jump to line 213 because the condition on line 212 was never true
213 raise OSError(f"File {filename!r} already exists.")
214 archive = cls(hdu_list, compression_options, opaque_metadata, compression_seed=compression_seed)
215 update_header(hdu_list[0].header)
216 # Set the creation date after update_header so a caller's callback
217 # cannot leave a stale DATE in the primary header; this card must
218 # always record the time of this write.
219 _set_creation_date(hdu_list[0].header)
220 yield archive
221 if not archive._json_hdu_added: 221 ↛ 222line 221 didn't jump to line 222 because the condition on line 221 was never true
222 raise RuntimeError("Write context exited without 'add_tree' being called.")
223 hdu_list.flush()
224 # This multi-open dance is necessary to get Astropy to tell us the
225 # byte addresses of the HDUs. Hopefully we can get an upstream change
226 # make this unnecessary at some point.
227 with astropy.io.fits.open(filename, mode="readonly", disable_image_compression=True) as hdu_list:
228 index_hdu = cls._make_index_table(hdu_list)
229 with astropy.io.fits.open(filename, mode="append") as hdu_list:
230 hdu_list.append(index_hdu)
231 json_bytes = _HDUBytes.from_index_row(index_hdu.data[-1])
232 index_bytes = _HDUBytes.from_write_hdu(index_hdu)
233 # Update the primary HDU with the address and size of the index and
234 # JSON HDUs, and rewrite just that. We do this write manually, since
235 # astropy's docs on its 'update' mode are scarce and it's not obvious
236 # whether we can guarantee it won't rewrite the whole file if we edit
237 # the primary header.
238 archive._primary_hdu.header["INDXADDR"] = index_bytes.header_address
239 archive._primary_hdu.header["INDXSIZE"] = index_bytes.size
240 archive._primary_hdu.header["JSONADDR"] = json_bytes.header_address
241 archive._primary_hdu.header["JSONSIZE"] = json_bytes.size
242 with open(filename, "r+b") as stream:
243 stream.write(archive._primary_hdu.header.tostring().encode())
245 def serialize_direct[T: pydantic.BaseModel | None](
246 self, name: str, serializer: Callable[[OutputArchive[PointerModel]], T]
247 ) -> T:
248 nested = NestedOutputArchive[PointerModel](name, self)
249 return serializer(nested)
251 def serialize_pointer[T: ArchiveTree](
252 self, name: str, serializer: Callable[[OutputArchive[PointerModel]], T], key: Hashable
253 ) -> PointerModel:
254 if (pointer := self._pointers_by_key.get(key)) is not None: 254 ↛ 255line 254 didn't jump to line 255 because the condition on line 254 was never true
255 return pointer
256 # Rooting the nested archive at "" follows the NestedOutputArchive
257 # convention that root paths are absolute, but serialize_direct roots
258 # at the bare name, so an array written by a pointer target would get
259 # a "/"-prefixed EXTNAME (e.g. "/DATA"). No serializer currently
260 # writes arrays inside pointer targets; if one ever does, consider
261 # rooting at ``name`` instead, as the NDF backend does.
262 model = self.serialize_direct("", serializer)
263 json_bytes = model.model_dump_json().encode()
264 self._pointer_targets.append(json_bytes)
265 pointer = PointerModel(
266 column=TableColumnModel(
267 name=JSON_COLUMN,
268 data=ArrayReferenceModel(
269 source=f"fits:{JSON_EXTNAME}[1]",
270 shape=[len(json_bytes)],
271 datatype=NumberType.uint8,
272 ),
273 ),
274 row=len(self._pointer_targets),
275 )
276 self._pointers_by_key[key] = pointer
277 return pointer
279 def serialize_frame_set[T: ArchiveTree](
280 self, name: str, frame_set: FrameSet, serializer: Callable[[OutputArchive], T], key: Hashable
281 ) -> PointerModel:
282 # Docstring inherited.
283 pointer = self.serialize_pointer(name, serializer, key)
284 self._frame_sets.append((frame_set, pointer))
285 return pointer
287 def iter_frame_sets(self) -> Iterator[tuple[FrameSet, PointerModel]]:
288 return iter(self._frame_sets)
290 def add_array(
291 self,
292 array: np.ndarray,
293 *,
294 name: str | None = None,
295 update_header: Callable[[astropy.io.fits.Header], None] = no_header_updates,
296 tile_shape: tuple[int, ...] | None = None,
297 options_name: str | None = None,
298 ) -> ArrayReferenceModel:
299 if name is None: 299 ↛ 300line 299 didn't jump to line 300 because the condition on line 299 was never true
300 raise RuntimeError("Cannot save array with name=None unless it is nested.")
301 name, version = self._register_name(name)
302 extname = name.upper()
303 hdu = self._opaque_metadata.maybe_use_precompressed(extname)
304 if hdu is None: 304 ↛ 311line 304 didn't jump to line 311 because the condition on line 304 was always true
305 if options_name is None: 305 ↛ 307line 305 didn't jump to line 307 because the condition on line 305 was always true
306 options_name = name
307 if (compression_options := self._get_compression_options(options_name, tile_shape)) is not None: 307 ↛ 310line 307 didn't jump to line 310 because the condition on line 307 was always true
308 hdu = compression_options.make_hdu(array, name=extname)
309 else:
310 hdu = astropy.io.fits.ImageHDU(array, name=extname)
311 key = self._add_hdu(hdu, version, update_header)
312 return ArrayReferenceModel(
313 source=str(key),
314 shape=list(array.shape),
315 datatype=NumberType.from_numpy(array.dtype),
316 )
318 def add_table(
319 self,
320 table: astropy.table.Table,
321 *,
322 name: str | None = None,
323 update_header: Callable[[astropy.io.fits.Header], None] = no_header_updates,
324 ) -> TableModel:
325 if name is None:
326 raise RuntimeError("Cannot save table with name=None unless it is nested.")
327 name, version = self._register_name(name)
328 extname = name.upper()
329 hdu: astropy.io.fits.BinTableHDU = astropy.io.fits.table_to_hdu(table, name=extname)
330 # Extract column information directly from the input array, not the
331 # data in the binary table HDU, because we want to assume as little as
332 # possible about where Astropy does uint -> TZERO stuff.
333 columns = TableColumnModel.from_table(table)
334 key = self._add_hdu(hdu, version, update_header)
335 for n, c in enumerate(columns, start=1):
336 assert isinstance(c.data, ArrayReferenceModel)
337 c.data.source = f"{key}[{n}]"
338 return TableModel(columns=columns, meta=table.meta)
340 def add_structured_array(
341 self,
342 array: np.ndarray,
343 *,
344 name: str | None = None,
345 units: Mapping[str, astropy.units.Unit] | None = None,
346 descriptions: Mapping[str, str] | None = None,
347 update_header: Callable[[astropy.io.fits.Header], None] = no_header_updates,
348 ) -> TableModel:
349 if name is None:
350 raise RuntimeError("Cannot save structured array with name=None unless it is nested.")
351 name, version = self._register_name(name)
352 extname = name.upper()
353 # Extract column information directly from the input array, not the
354 # data in the binary table HDU, because we want to assume as little as
355 # possible about where Astropy does uint -> TZERO stuff.
356 columns = TableColumnModel.from_record_dtype(array.dtype)
357 hdu = astropy.io.fits.BinTableHDU(array, name=extname)
358 if units is not None:
359 for c in columns:
360 c.unit = units.get(c.name)
361 if descriptions is not None:
362 for c in columns:
363 c.description = descriptions.get(c.name, "")
364 key = self._add_hdu(hdu, version, update_header)
365 for n, c in enumerate(columns, start=1):
366 assert isinstance(c.data, ArrayReferenceModel)
367 c.data.source = f"{key}[{n}]"
368 return TableModel(columns=columns)
370 def _add_hdu(
371 self,
372 hdu: astropy.io.fits.ImageHDU | astropy.io.fits.CompImageHDU | astropy.io.fits.BinTableHDU,
373 version: int,
374 update_header: Callable[[astropy.io.fits.Header], None] = no_header_updates,
375 ) -> ExtensionKey:
376 key = ExtensionKey(hdu.name, version)
377 key.check()
378 if version > 1:
379 hdu.header["EXTVER"] = version
380 update_header(hdu.header)
381 if (opaque_headers := self._opaque_metadata.headers.get(key)) is not None:
382 hdu.header.extend(opaque_headers)
383 _set_creation_date(hdu.header)
384 self._hdu_list.append(hdu)
385 return key
387 def add_tree(self, tree: ArchiveTree) -> None:
388 """Write the JSON tree to the archive.
390 This method must be called exactly once, just before the `open` context
391 is exited.
393 Parameters
394 ----------
395 tree
396 Pydantic model that represents the tree.
397 """
398 self._primary_hdu.header.set("DATAMODL", tree.schema_url, "Schema URL.")
399 json_hdu = astropy.io.fits.BinTableHDU.from_columns(
400 [astropy.io.fits.Column(JSON_COLUMN, "PB")],
401 nrows=len(self._pointer_targets) + 1,
402 name=JSON_EXTNAME,
403 )
404 json_hdu.data[0][JSON_COLUMN] = np.frombuffer(tree.model_dump_json().encode(), dtype=np.byte)
405 for n, json_target_data in enumerate(self._pointer_targets):
406 json_hdu.data[n + 1][JSON_COLUMN] = np.frombuffer(json_target_data, dtype=np.byte)
407 _set_creation_date(json_hdu.header)
408 self._hdu_list.append(json_hdu)
409 self._json_hdu_added = True
411 def _get_compression_options(
412 self, name: str, tile_shape: tuple[int, ...] | None
413 ) -> FitsCompressionOptions | None:
414 result = self._compression_options.get(name, FitsCompressionOptions.DEFAULT)
415 if result is None: 415 ↛ 416line 415 didn't jump to line 416 because the condition on line 415 was never true
416 return result
417 if tile_shape is not None and result.tile_shape is None: 417 ↛ 418line 417 didn't jump to line 418 because the condition on line 417 was never true
418 result = result.model_copy(update={"tile_shape": tile_shape})
419 if result.quantization is None:
420 return result
421 if self._compression_seed is not None and not result.quantization.seed: 421 ↛ 432line 421 didn't jump to line 432 because the condition on line 421 was always true
422 result = result.model_copy(
423 update={
424 "quantization": result.quantization.model_copy(update={"seed": self._compression_seed})
425 }
426 )
427 self._compression_seed += 1
428 if self._compression_seed > 10000: 428 ↛ 429line 428 didn't jump to line 429 because the condition on line 428 was never true
429 self._compression_seed = 1
430 # MyPy can tell that result.quantization is not None in the 'if', but
431 # forgets that by this 'else':
432 elif result.quantization.seed is None: # type: ignore[union-attr]
433 raise RuntimeError("No quantization seed provided.")
434 return result
436 @staticmethod
437 def _make_index_table(hdu_list: astropy.io.fits.HDUList) -> astropy.io.fits.BinTableHDU:
438 # We use a fixed-length string for the EXTNAME column; it might be
439 # better to use a variable-length array, but I have not been able to
440 # figure out how to get astropy to accept a string for the the
441 # character (TFORM='A') variant of that. And that's only better if the
442 # EXTNAMEs get super long, which is not likely (but maybe something to
443 # guard against).
444 max_name_size = max(len(hdu.header.get("EXTNAME", "")) for hdu in hdu_list)
445 # Attach the ZIMAGE values as a boolean array on the Column itself.
446 # Astropy only fills a logical column's raw bytes with 'F' as the
447 # default (rather than NULL, 0x00) when the bool array is present at
448 # construction; assigning False element-wise after construction leaves
449 # the byte as NULL under Astropy 8.0.0, which warns on every read.
450 # Should be fixed in v8.0.1.
451 # See https://github.com/astropy/astropy/pull/19939
452 # but pre-allocating the entire column works in v7 and v8.
453 zimage = np.array([hdu.header.get("ZIMAGE", False) for hdu in hdu_list], dtype=bool)
454 index_hdu = astropy.io.fits.BinTableHDU.from_columns(
455 [
456 astropy.io.fits.Column("EXTNAME", f"A{max_name_size}"),
457 astropy.io.fits.Column("EXTVER", "J"),
458 astropy.io.fits.Column("XTENSION", "A8"),
459 astropy.io.fits.Column("ZIMAGE", "L", array=zimage),
460 ]
461 + _HDUBytes.get_index_hdu_columns(),
462 nrows=len(hdu_list),
463 name="INDEX",
464 )
465 hdu: ExtensionHDU | astropy.io.fits.PrimaryHDU
466 for n, hdu in enumerate(hdu_list):
467 index_hdu.data[n]["EXTNAME"] = hdu.header.get("EXTNAME", "")
468 index_hdu.data[n]["EXTVER"] = hdu.header.get("EXTVER", 1)
469 index_hdu.data[n]["XTENSION"] = hdu.header.get("XTENSION", "IMAGE")
470 bytes = _HDUBytes.from_read_hdu(hdu)
471 bytes.update_index_row(index_hdu.data[n])
472 _set_creation_date(index_hdu.header)
473 return index_hdu
476@dataclasses.dataclass
477class _HDUBytes:
478 """A struct that records the byte offsets into a FITS HDU."""
480 @classmethod
481 def from_write_hdu(cls, hdu: astropy.io.fits.PrimaryHDU | ExtensionHDU) -> Self:
482 """Construct from an Astropy HDU instance that has just been written.
484 Parameters
485 ----------
486 hdu
487 An Astropy HDU object.
489 Returns
490 -------
491 hdu_bytes
492 Struct with byte offsets.
494 Notes
495 -----
496 This method relies on internal Astropy attributes and does not work on
497 CompImageHDU objects.
498 """
499 # This is implemented by accessing private Astropy attributes because
500 # it turns out that's much more reliable than the public fileinfo()
501 # method, which seems to always return a dict with `None` entries or
502 # raise; it looks buggy, but docs are scarce enough that it's not clear
503 # what the right behavior is supposed to be.
504 if (header_address := getattr(hdu, "_header_offset", None)) is None: 504 ↛ 505line 504 didn't jump to line 505 because the condition on line 504 was never true
505 raise RuntimeError("Failed to get Astropy's _header_offset.")
506 if (data_address := getattr(hdu, "_data_offset", None)) is None: 506 ↛ 507line 506 didn't jump to line 507 because the condition on line 506 was never true
507 raise RuntimeError("Failed to get Astropy's _data_offset.")
508 if (data_size := getattr(hdu, "_data_size", None)) is None: 508 ↛ 509line 508 didn't jump to line 509 because the condition on line 508 was never true
509 raise RuntimeError("Failed to get Astropy's _data_size.")
510 return cls(header_address, data_address, data_size)
512 @classmethod
513 def from_read_hdu(cls, hdu: astropy.io.fits.PrimaryHDU | ExtensionHDU) -> Self:
514 """Construct from an Astropy HDU instance that has just been read.
516 Parameters
517 ----------
518 hdu
519 An Astropy HDU object.
521 Returns
522 -------
523 hdu_bytes
524 Struct with byte offsets.
525 """
526 info = hdu.fileinfo()
527 header_address = info["hdrLoc"]
528 data_address = info["datLoc"]
529 data_size = info["datSpan"]
530 return cls(header_address, data_address, data_size)
532 @classmethod
533 def from_index_row(cls, row: np.void) -> Self:
534 """Construct from a row of the index HDU.
536 Parameters
537 ----------
538 row
539 A Numpy struct-like scalar.
541 Returns
542 -------
543 hdu_bytes
544 Struct with byte offsets.
545 """
546 return cls(
547 header_address=int(row["HDRADDR"]),
548 data_address=int(row["DATADDR"]),
549 data_size=int(row["DATSIZE"]),
550 )
552 @staticmethod
553 def get_index_hdu_columns() -> list[astropy.io.fits.Column]:
554 """Return the definitions of the columns this class gets and sets
555 from the index HDU.
557 Returns
558 -------
559 columns
560 A `list` of `astropy.io.fits.Column` objects that represent the
561 header address, data address, and data size.
562 """
563 return [
564 astropy.io.fits.Column("HDRADDR", "K"),
565 astropy.io.fits.Column("DATADDR", "K"),
566 astropy.io.fits.Column("DATSIZE", "K"),
567 ]
569 header_address: int
570 """Offset from the beginning of the start of the file to the header of this
571 HDU, in bytes.
572 """
574 data_address: int
575 """Offset from the beginning of the start of the file to the data section
576 of this HDU, in bytes.
577 """
579 data_size: int
580 """Size of the data section in bytes."""
582 @property
583 def header_size(self) -> int:
584 """Size of the header in bytes."""
585 return self.data_address - self.header_address
587 @property
588 def end_address(self) -> int:
589 """Offset in bytes from the start of the file to the end of the HDU."""
590 return self.data_address + self.data_size
592 @property
593 def size(self) -> int:
594 """Total size of this HDU in bytes."""
595 return self.data_size + self.data_address - self.header_address
597 def update_index_row(self, row: np.void) -> None:
598 """Set the values of a row of the index HDU from this strut.
600 Parameters
601 ----------
602 row
603 A Numpy struct-like scalar to modify in place.
604 """
605 row["HDRADDR"] = self.header_address
606 row["DATADDR"] = self.data_address
607 row["DATSIZE"] = self.data_size