Biblio::Isis(3pm)

NAME
Biblio::Isis - Read CDS/ISIS, WinISIS and IsisMarc database

SYNOPSIS
  use Biblio::Isis;

  my $isis = new Biblio::Isis(
        isisdb => './cds/cds',
  );

  for(my $mfn = 1; $mfn <= $isis->count; $mfn++) {
        print $isis->to_ascii($mfn),"\n";
  }

DESCRIPTION
This module will read ISIS databases created by DOS CDS/ISIS, WinIsis or IsisMarc. It can be used as perl-only alternative to OpenIsis module which seems to depriciate it's old "XS" bindings for perl.

It can create hash values from data in ISIS database (using "to_hash"), ASCII dump (using "to_ascii") or just hash with field names and packed values (like "^asomething^belse").

Unique feature of this module is ability to "include_deleted" records. It will also skip zero sized fields (OpenIsis has a bug in XS bindings, so fields which are zero sized will be filled with random junk from memory).

It also has support for identifiers (only if ISIS database is created by IsisMarc), see "to_hash".

This module will always be slower than OpenIsis module which use C library. However, since it's written in perl, it's platform independent (so you don't need C compiler), and can be easily modified. I hope that it creates data structures which are easier to use than ones created by OpenIsis, so reduced time in other parts of the code should compensate for slower performance of this module (speed of reading ISIS database is rarely an issue).

METHODS

  new
Open ISIS database

 my $isis = new Biblio::Isis(
        isisdb => './cds/cds',
        read_fdt => 1,
        include_deleted => 1,
        hash_filter => sub {
                my ($v,$field_number) = @_;
                $v =~ s#foo#bar#g;
        },
        debug => 1,
        join_subfields_with => ' ; ',
 );

Options are described below:

isisdb
    This is full or relative path to ISIS database files which include common prefix of ".MST", and ".XRF" and optionally ".FDT" (if using "read_fdt" option) files.

    In this example it uses "./cds/cds.MST" and related files.

read_fdt
    Boolean flag to specify if field definition table should be read. It's off by default.

include_deleted
    Don't skip logically deleted records in ISIS.

hash_filter
    Filter code ref which will be used before data is converted to hash. It will receive two arguments, whole line from current field (in $_[0]) and field number (in $_[1]).

debug
    Dump a lot of debugging output even at level 1. For even more increase level.

join_subfields_with
    Define delimiter which will be used to join repeatable subfields. This option is included to support lagacy application written against version older than 0.21 of this module. By default, it disabled. See "to_hash".

ignore_empty_subfields
    Remove all empty subfields while reading from ISIS file.

  count
Return number of records in database

  print $isis->count;

  fetch
Read record with selected MFN

  my $rec = $isis->fetch(55);

Returns hash with keys which are field names and values are unpacked values for that field like this:

  $rec = {
    '210' => [ '^aNew York^cNew York University press^dcop. 1988' ],
    '990' => [ '2140', '88', 'HAY' ],
  };

  mfn
Returns current MFN position

  my $mfn = $isis->mfn;

  to_ascii
Returns ASCII output of record with specified MFN

  print $isis->to_ascii(42);

This outputs something like this:

  210   ^aNew York^cNew York University press^dcop. 1988
  990   2140
  990   88
  990   HAY

If "read_fdt" is specified when calling "new" it will display field names from ".FDT" file instead of numeric tags.

  to_hash
Read record with specified MFN and convert it to hash

  my $hash = $isis->to_hash($mfn);

It has ability to convert characters (using "hash_filter") from ISIS database before creating structures enabling character re-mapping or quick fix-up of data.

This function returns hash which is like this:

  $hash = {
    '210' => [
               {
                 'c' => 'New York University press',
                 'a' => 'New York',
                 'd' => 'cop. 1988'
               }
             ],
    '990' => [
               '2140',
               '88',
               'HAY'
             ],
  };

You can later use that hash to produce any output from ISIS data.

If database is created using IsisMarc, it will also have to special fields which will be used for identifiers, "i1" and "i2" like this:

  '200' => [
             {
               'i1' => '1',
               'i2' => ' '
               'a' => 'Goa',
               'f' => 'Valdo D\'Arienzo',
               'e' => 'tipografie e tipografi nel XVI secolo',
             }
           ],

In case there are repeatable subfields in record, this will create following structure:

  '900' => [ {
        'a' => [ 'foo', 'bar', 'baz' ],
  }]

Or in more complex example of

  902   ^aa1^aa2^aa3^bb1^aa4^bb2^cc1^aa5

it will create

  902   => [
        { a => ["a1", "a2", "a3", "a4", "a5"], b => ["b1", "b2"], c => "c1" },
  ],

This behaviour can be changed using "join_subfields_with" option to "new", in which case "to_hash" will always create single value for each subfield. This will change result to:

This method will also create additional field 000 with MFN.

There is also more elaborative way to call "to_hash" like this:

  my $hash = $isis->to_hash({
        mfn => 42,
        include_subfields => 1,
  });

Each option control creation of hash:

mfn Specify MFN number of record

include_subfields
    This option will create additional key in hash called "subfields" which will have original record subfield order and index to that subfield like this:

      902   => [ {
            a => ["a1", "a2", "a3", "a4", "a5"],
            b => ["b1", "b2"],
            c => "c1",
            subfields => ["a", 0, "a", 1, "a", 2, "b", 0, "a", 3, "b", 1, "c", 0, "a", 4],
      } ],

join_subfields_with
    Define delimiter which will be used to join repeatable subfields. You can specify option here instead in "new" if you want to have per-record control.

hash_filter
    You can override "hash_filter" defined in "new" using this option.

  tag_name
Return name of selected tag

 print $isis->tag_name('200');

  read_cnt
Read content of ".CNT" file and return hash containing it.

  print Dumper($isis->read_cnt);

This function is not used by module (".CNT" files are not required for this module to work), but it can be useful to examine your index (while debugging for example).

  unpack_cnt
Unpack one of two 26 bytes fixed length record in ".CNT" file.

Here is definition of record:

 off key        description                             size
  0: IDTYPE     BTree type                              s
  2: ORDN       Nodes Order                             s
  4: ORDF       Leafs Order                             s
  6: N          Number of Memory buffers for nodes      s
  8: K          Number of buffers for first level index s
 10: LIV        Current number of Index Levels          s
 12: POSRX      Pointer to Root Record in N0x           l
 16: NMAXPOS    Next Available position in N0x          l
 20: FMAXPOS    Next available position in L0x          l
 24: ABNORMAL   Formal BTree normality indicator        s
 length: 26 bytes

This will fill $self object under "cnt" with hash. It's used by "read_cnt".

BUGS
Some parts of CDS/ISIS documentation are not detailed enough to exmplain some variations in input databases which has been tested with this module. When I was in doubt, I assumed that OpenIsis's implementation was right (except for obvious bugs).

However, every effort has been made to test this module with as much databases (and programs that create them) as possible.

I would be very greatful for success or failure reports about usage of this module with databases from programs other than WinIsis and IsisMarc. I had tested this against output of one "isis.dll"-based application, but I don't know any details about it's version.

VERSIONS
As this is young module, new features are added in subsequent version. It's a good idea to specify version when using this module like this:

  use Biblio::Isis 0.23

Below is list of changes in specific version of module (so you can target older versions if you really have to):

0.24
    Added "ignore_empty_subfields"

0.23
    Added "hash_filter" to "to_hash"

    Fixed bug with documented "join_subfields_with" in "new" which wasn't implemented

0.22
    Added field number when calling "hash_filter"

0.21
    Added "join_subfields_with" to "new" and "to_hash".

    Added "include_subfields" to "to_hash".

0.20
    Added "$isis->mfn", support for repeatable subfields and "$isis->to_hash({ mfn => 42, ... })" calling convention

AUTHOR
        Dobrica Pavlinusic
        CPAN ID: DPAVLIN
        dpavlin@rot13.org
        http://www.rot13.org/~dpavlin/

This module is based heavily on code from "LIBISIS.PHP" library to read ISIS files V0.1.1 written in php and (c) 2000 Franck Martin <franck@sopac.org> and released under LGPL.

COPYRIGHT
This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

The full text of the license can be found in the LICENSE file included with this module.

SEE ALSO
Biblio::Isis::Manual for CDS/ISIS manual appendix F, G and H which describe file format

OpenIsis web site <http://www.openisis.org>

perl4lib site <http://perl4lib.perl.org>