From: daz <dooby@...10.karoo.co.uk>
Date: 2003-06-04T13:15:02+09:00
Subject: Re: file I/O: how can I disable auto-convert of the 2-byte sequence 0x0D, 0x0A into a single byte '\n'?

file I/O: how can I disable auto-convert of the 2-byte sequence 0x0D, 0x0A into a single byte '\n'?
"Polscheit, Frank" <frank.polscheit@gzs.de> wrote:

>Hi,

>I want to process binary data, which can contain such byte sequences
> but not indicating end-of-line as the file has a fix record length.

>Best regards,
>Frank

And here's an example.

#---------
FIXREC_LEN = 10
FIXPAD_CHR = '!'

File.open('result.dat', 'wb') do |fo|
  File.open('test.dat', 'rb') do |fi|
    until fi.eof
      dat = fi.read(FIXREC_LEN)
      p [dat, dat[4], dat[5]]
      dat_new = dat.gsub(/\r\n/, "\n\r")
      fo.write(dat_new << FIXPAD_CHR * (FIXREC_LEN-dat.size))
    end
  end
end  # files close automatically for File.open {block}

puts '-' * 30

File.open('result.dat', 'rb') do |fi|
  until fi.eof
    dat = fi.read(FIXREC_LEN)
    p [dat, dat[4], dat[5]]
  end
end
#---------


Output:

["ERST\r\nZWEI", 13, 10]
["T\r\nDRITT\r\n", 82, 73]
["VIERT\r\n", 84, 13]
------------------------------
["ERST\n\rZWEI", 10, 13]
["T\n\rDRITT\n\r", 82, 73]
["VIERT\n\r!!!", 84, 10]


#File dumps:

## test.dat
# 000:  45 52 53 54 0d 0a 5a 57 45 49  ERST..ZWEI
# 010:  54 0d 0a 44 52 49 54 54 0d 0a  T..DRITT..
# 020:  56 49 45 52 54 0d 0a           VIERT..

## result.dat
# 000:  45 52 53 54 0a 0d 5a 57 45 49  ERST..ZWEI
# 010:  54 0a 0d 44 52 49 54 54 0a 0d  T..DRITT..
# 020:  56 49 45 52 54 0a 0d 21 21 21  VIERT..!!!


daz