/ 
Biblio-Isis-0.24
River stage zero No dependents
/ Biblio::Isis

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 controll 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 ouput 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