| Re: carriage-return-carriage-control [message #25961 is a reply to message #25890] |
Fri, 27 July 2001 05:21  |
Alex Schuster
Messages: 124
Registered: February 1997
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Senior Member |
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Lucas Miller wrote:
> I'm working on a vax with IDL 4.0 :) I have a HUGE binary file,
> with sequential, variable length records separated by a carriage return
> carriage control character. The problem is that the records aren't in the
I don't know exactly what this carriage control stuff ist... can the
next record be identified just by finding the carrage returns (CR, ASCII
code 13)?
> right order! Each record has a header with a time stamp that I can use to
> sort the file with. Any suggestions on how to read from the file and figure
> out where each record begins? I've tried so many things! Please help!
If your file fits completely into memory (if it's HUGE it probably
doesn't), read it via READU:
openr, unit, filename, /get_lun
array = bytarr( (fstat(unit)).size )
readu, unit, array
free_lun, unit
record_start = where( array eq 13b, n ) + 1
timestamps = array[record_start]
; or something like that, depending on how this timestamp is defined
sort_index = sort( timestamps )
If your file is too huge, try reading it in chunks, and have a look at
the ASSOC() function.
Alex
--
Alex Schuster Wonko@planet-interkom.de
alex@pet.mpin-koeln.mpg.de
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