From: niklas | brueckenschlaeger <niklas@...>
Date: 2011-02-24T07:07:14+09:00
Subject: Re: finding a tag in a binary file

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Example:
  byte =3D 0b00100010
  # clear the trailing 4 bit, then shift:
  first_four_bits =3D (byte & 0b11110000) >> 4
  # clear the leading 4 bits:
  last_four_bits =3D byte & 0b1111

btw., your code would be shorter as:
   open('1DICOMDIR', 'rb') { |f|
     contentsArray =3D f.each_byte.to_a
   }

(also it's not so common to use camelCase in the ruby world, we usually
prefer under_scored_identifiers, butThatsUpToYou...)

By default ruby will print numbers as decimal, however you can look at
them in other ways by using to_s and passing in a base:
  123.to_s(16) #=3D> "7b"
  123.to_s(2) #=3D> "1111011"

hope this helps.

 -- niklas

On Thu, 2011-02-24 at 06:28 +0900, rob s. wrote:
> Hi I'm a complete non programmer but willing to give it a try.
>=20
> I have a DICOMDIR (medical imaging file) which has various tags in,
> following a tag ie 0010, 0010 is the "patient name", "study date"
> 0008,0020 is another.
>=20
> I have several DICOMDIR and I would like to extract just a few bits of
> information from them to a .txt file, the files average size is about
> 343 KB as its full of other information as well which I don't need. Each
> file has amongst other things a list of about 10 names, scan dates etc.
>=20
> So far I've managed to read the file into an array using
>=20
> contentsArray=3D[]    #open new array empty
>=20
> open('1DICOMDIR', 'rb') { |f| f.each_byte { |f| contentsArray.push f } }
>=20
> This gets the info into an array
>=20
> although its a hex file it displays the contents in decimal, but they
> correspond to the hex codes I've seen in a hex editor...
>=20
> My problem is I don't know how to detect 0010,0010 ? then extract the
> name. Can anyone help, I've looked all over the web but not finding
> anything to help me much. Thanks a lot
>=20


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