LSST Applications  21.0.0-172-gfb10e10a+18fedfabac,22.0.0+297cba6710,22.0.0+80564b0ff1,22.0.0+8d77f4f51a,22.0.0+a28f4c53b1,22.0.0+dcf3732eb2,22.0.1-1-g7d6de66+2a20fdde0d,22.0.1-1-g8e32f31+297cba6710,22.0.1-1-geca5380+7fa3b7d9b6,22.0.1-12-g44dc1dc+2a20fdde0d,22.0.1-15-g6a90155+515f58c32b,22.0.1-16-g9282f48+790f5f2caa,22.0.1-2-g92698f7+dcf3732eb2,22.0.1-2-ga9b0f51+7fa3b7d9b6,22.0.1-2-gd1925c9+bf4f0e694f,22.0.1-24-g1ad7a390+a9625a72a8,22.0.1-25-g5bf6245+3ad8ecd50b,22.0.1-25-gb120d7b+8b5510f75f,22.0.1-27-g97737f7+2a20fdde0d,22.0.1-32-gf62ce7b1+aa4237961e,22.0.1-4-g0b3f228+2a20fdde0d,22.0.1-4-g243d05b+871c1b8305,22.0.1-4-g3a563be+32dcf1063f,22.0.1-4-g44f2e3d+9e4ab0f4fa,22.0.1-42-gca6935d93+ba5e5ca3eb,22.0.1-5-g15c806e+85460ae5f3,22.0.1-5-g58711c4+611d128589,22.0.1-5-g75bb458+99c117b92f,22.0.1-6-g1c63a23+7fa3b7d9b6,22.0.1-6-g50866e6+84ff5a128b,22.0.1-6-g8d3140d+720564cf76,22.0.1-6-gd805d02+cc5644f571,22.0.1-8-ge5750ce+85460ae5f3,master-g6e05de7fdc+babf819c66,master-g99da0e417a+8d77f4f51a,w.2021.48
LSST Data Management Base Package
checksum.py
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1 import hashlib
2 import zlib
3 import pickle
4 
5 import lsst.afw.image as afwImage
6 
7 __all__ = ["checksum", ]
8 
9 # Image types to support
10 exposureTypes = (afwImage.ExposureF, afwImage.ExposureD,)
11 maskedImageTypes = (afwImage.MaskedImageF, afwImage.MaskedImageD,)
12 decoratedImageTypes = (afwImage.DecoratedImageF, afwImage.DecoratedImageD,)
13 imageTypes = (afwImage.ImageF, afwImage.ImageD, afwImage.ImageI,)
14 
15 PROTOCOL = 2 # Pickling protocol
16 
17 # Functions for creating the checksum
18 sumFunctions = {
19  "CRC32": lambda obj: zlib.crc32(pickle.dumps(obj, PROTOCOL)),
20  "MD5": lambda obj: hashlib.md5(pickle.dumps(obj, PROTOCOL)).hexdigest(),
21 }
22 
23 
24 def checksum(obj, header=None, sumType="MD5"):
25  """!Calculate a checksum of an object
26 
27  We have special handling for images (e.g., breaking a MaskedImage into
28  its various components), but the object may be any picklable type.
29 
30  @param obj Object for which to calculate the checksum
31  @param header FITS header (PropertyList) to update with checksum values, or None
32  @param sumType Type of checksum to calculate
33  @return dict with header keyword,value pairs
34  """
35  assert sumType in sumFunctions, "Unknown sumType: %s" % (sumType,)
36  func = sumFunctions[sumType]
37 
38  results = {}
39 
40  if isinstance(obj, exposureTypes):
41  obj = obj.getMaskedImage()
42  if isinstance(obj, decoratedImageTypes):
43  obj = obj.getImage()
44 
45  if isinstance(obj, maskedImageTypes):
46  results[sumType + "_IMAGE"] = func(obj.getImage())
47  results[sumType + "_MASK"] = func(obj.getMask())
48  results[sumType + "_VARIANCE"] = func(obj.getVariance())
49  elif isinstance(obj, imageTypes):
50  results[sumType + "_IMAGE"] = func(obj)
51  else:
52  results[sumType] = func(obj)
53 
54  if header is not None:
55  for k, v in results.items():
56  header.add(k, v)
57 
58  return results
Backwards-compatibility support for depersisting the old Calib (FluxMag0/FluxMag0Err) objects.
def checksum(obj, header=None, sumType="MD5")
Calculate a checksum of an object.
Definition: checksum.py:24