Re: 2. Re: How to compress data in RPGLE and save it in a file and

[Scott Klement <klemscot@xxxxxxxxxxxx>]

Hi,

*PLEASE* don't quote back the entire digest when you reply.  Just quote
back the part of the message that you're replying to.  Thanks!

My answer is below.

[SNIP]
> I can easily do it on PC platform but wondering if there is any utility or
> functionality within OS/400 which can help us to do what we are trying to
> do.  Meaning save the disk space by compressing it and also be able to
> recover data from compress mode within seconds.

Do you mean something similar to the .ZIP capability on the PC?  There are
several similar utilities available for OS/400.

[SNIP]
> Any idea how to solve this issue?  It's all regular data (numbers/strings).
> For one order we have 100s of files and there are 100s of fields in each one
> of them.  Don't ask why we have so many files and fields.  (FYI: It's all
> custom development of many years). We would like to compress this data by
> order number so that we can easily retrieve it.
[SNIP]

Here's a few ideas:

1) Put each file into a compressed save file.  This capability is built
    into OS/400.
      To compress:
        CRTSAVF FILE(SAVF0001)
        SAVOBJ OBJ(FILE0001) LIB(MYLIB) DEV(*SAVF) SAVF(MYLIB/SAVF0001) +
              DTACPR(*YES)
        DLTF MYLIB/FILE0001

      To decompress:
        CHKOBJ OBJ(MYLIB/FILE0001) OBJTYPE(*FILE)
        MONMSG MSGID(CPF9801) EXEC(DO)
            RSTOBJ OBJ(FILE0001) SAVLIB(MYLIB) DEV(*SAVF) +
                   SAVF(MYLIB/SAVF0001)
        ENDDO

2) Use the JAR utility that comes with Java to compress the data.  This
      creates .ZIP files just like the PC utilities.  Not sure how well
      it works with OS/400 data files, though you could experiment.

      These are a QShell commands, run using the STRQSH command if
      you want to put it into a CL program or run it from QCMDEXC, etc

    to compress:
      mkdir /archives
      cd /qsys.lib/mylib.lib/myfile.file
      jar cMf /archives/file0001.zip mymember.mbr
      rm -r /qsys.lib/mylib.lib/myfile.file

    to decompress:
      system "crtpf mylib/myfile"
      cd /qsys.lib/mylib.lib/myfile.file
      jar xf /archives/file0001.zip mymember.mbr

    WARNING:  This process treats the files like PC-style stream files
      and therefore you will lose any OS/400-specific information in
      the object and member descriptions.  (Save files do not have
      this problem)

3) Get the GNU GZIP utility for OS/400.  GZIP is an open-source file
      compression utility commonly used on Linux, FreeBSD, and similar
      systems.  It does a better job, IMHO, of compression than .ZIP
      does but will have the same problem with losing description info.

      The OS/400 port can be found here
http://www-1.ibm.com/servers/enable/site/porting/iseries/overview/gnu_utilities.html

      Again, these are QShell commands.

    To compress:
      cd /qsys.lib/mylib.lib/myfile.file
      gzip -9c mymember.mbr > /archives/mymember.gz
      rm -r /qsys.lib/mylib.lib/myfile.file

    to decompress:
      system "crtpf mylib/myfile"
      gzip -dc /archives/mymember.gz > /tmp/mymember.mbr
      cd /qsys.lib/mylib.lib/myfile.file
      cp /tmp/mymember.mbr mymember.mbr

4) As someone else suggested already, there's a native PKZIP software
      for OS/400.  You could purchase that and use it...