BUG: DCMTK reader wrongly rejects file with preamble

[pieper]

A previous optimization didn't take into account the premable of a dicom file. This adds a check.

Fixes #4108

[pieper]

@hjmjohnson could you have a look at this?

It fixes #4108

[issakomi]

I confirm that DCMTKIO's DCMTKImageIO::CanReadFile function returns false for valid DICOM files with preamble. I have reproduced it just now.

[jhlegarreta]

Thanks for doing this @pieper. I am willing to give this a 👍 when the following are addressed:

• We're trying to remove/have removed whitespaces before the scope resolution operator, e.g.
  STYLE: Remove space between class and member names (follow-up) #3664
  so please remove them, e.g.
  https://github.com/InsightSoftwareConsortium/ITK/pull/4110/files#diff-4f73091b3003136c994a445b6eda56d8ac3e9044936fbb78a0649164a8c31a73R68
• The output stream << insertion operators were removed from itkExceptionMacro calls in: https://github.com/InsightSoftwareConsortium/ITK/pull/4057/files, so please remove them:
  https://github.com/InsightSoftwareConsortium/ITK/pull/4110/files#diff-4f73091b3003136c994a445b6eda56d8ac3e9044936fbb78a0649164a8c31a73R94
  If they should be added back, a separate commit and PR are required.
• Please document the method in the header file:
  https://github.com/InsightSoftwareConsortium/ITK/pull/4110/files#diff-4f73091b3003136c994a445b6eda56d8ac3e9044936fbb78a0649164a8c31a73R135
• Adding a test that demonstrates the issue would be required to ensure that we do not run into this issue again.

In general, commits should only fall into one category, BUG, DOC, STYLE, etc. Helps reviewing, keeping changes of different nature separate, keeping a clean history, etc.

[pieper]

Thanks for the review @jhlegarreta - I had tried to add just the one function but it looks like my checkout was against an older target. I'll fix it.

[dzenanz]

@pieper did you have time to address Jon's feedback?

[thewtex]

This could be removed following seek to 0

[thewtex]

#4501 has updates with @jhlegarreta requests addressed (note that readPreampleDicom is not in the header, so it is moved to an anonymous namespace instead). Also, replaced the file re-open, close with a seek. Replace and with &&.

[thewtex]

Superceded by #4501