lib/Biblio/Isis.pm

package Biblio::Isis;
use strict;

use Carp;
use File::Glob qw(:globally :nocase);

BEGIN {
        use Exporter ();
        use vars qw ($VERSION @ISA @EXPORT @EXPORT_OK %EXPORT_TAGS);
        $VERSION     = 0.14;
        @ISA         = qw (Exporter);
        #Give a hoot don't pollute, do not export more than needed by default
        @EXPORT      = qw ();
        @EXPORT_OK   = qw ();
        %EXPORT_TAGS = ();

}

=head1 NAME

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

=head1 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";
  }

=head1 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 C<XS> bindings for perl.

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

Unique feature of this module is ability to C<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 C<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).

=head1 METHODS

=cut

#  my $ORDN;            # Nodes Order
#  my $ORDF;            # Leafs Order
#  my $N;               # Number of Memory buffers for nodes
#  my $K;               # Number of buffers for first level index
#  my $LIV;             # Current number of Index Levels
#  my $POSRX;           # Pointer to Root Record in N0x
#  my $NMAXPOS;         # Next Available position in N0x
#  my $FMAXPOS;         # Next available position in L0x
#  my $ABNORMAL;        # Formal BTree normality indicator

#
# some binary reads
#

=head2 new

Open ISIS database

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

Options are described below:

=over 5

=item isisdb

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

In this example it uses C<./cds/cds.MST> and related files.

=item read_fdt

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

=item include_deleted

Don't skip logically deleted records in ISIS.

=item hash_filter

Filter code ref which will be used before data is converted to hash.

=item debug

Dump a B<lot> of debugging output.

=back

=cut

sub new {
        my $class = shift;
        my $self = {};
        bless($self, $class);

        croak "new needs database name (isisdb) as argument!" unless ({@_}->{isisdb});

        foreach my $v (qw{isisdb debug include_deleted hash_filter}) {
                $self->{$v} = {@_}->{$v};
        }

        my @isis_files = grep(/\.(FDT|MST|XRF|CNT)$/i,glob($self->{isisdb}."*"));

        foreach my $f (@isis_files) {
                my $ext = $1 if ($f =~ m/\.(\w\w\w)$/);
                $self->{lc($ext)."_file"} = $f;
        }

        my @must_exist = qw(mst xrf);
        push @must_exist, "fdt" if ($self->{read_fdt});

        foreach my $ext (@must_exist) {
                unless ($self->{$ext."_file"}) {
                        carp "missing ",uc($ext)," file in ",$self->{isisdb};
                        return;
                }
        }

        if ($self->{debug}) {
                print STDERR "## using files: ",join(" ",@isis_files),"\n";
                eval "use Data::Dump";

                if (! $@) {
                        *Dumper = *Data::Dump::dump;
                } else {
                        use Data::Dumper;
                }
        }

        # if you want to read .FDT file use read_fdt argument when creating class!
        if ($self->{read_fdt} && -e $self->{fdt_file}) {

                # read the $db.FDT file for tags
                my $fieldzone=0;

                open(my $fileFDT, $self->{fdt_file}) || croak "can't read '$self->{fdt_file}': $!";
                binmode($fileFDT);

                while (<$fileFDT>) {
                        chomp;
                        if ($fieldzone) {
                                my $name=substr($_,0,30);
                                my $tag=substr($_,50,3);

                                $name =~ s/\s+$//;
                                $tag =~ s/\s+$//;

                                $self->{'TagName'}->{$tag}=$name;  
                        }

                        if (/^\*\*\*/) {
                                $fieldzone=1;
                        }
                }
                
                close($fileFDT);
        }

        # Get the Maximum MFN from $db.MST

        open($self->{'fileMST'}, $self->{mst_file}) || croak "can't open '$self->{mst_file}': $!";
        binmode($self->{'fileMST'});

        # MST format:   (* = 32 bit signed)
        # CTLMFN*       always 0
        # NXTMFN*       MFN to be assigned to the next record created
        # NXTMFB*       last block allocated to master file
        # NXTMFP        offset to next available position in last block
        # MFTYPE        always 0 for user db file (1 for system)
        seek($self->{'fileMST'},4,0) || croak "can't seek to offset 0 in MST: $!";

        my $buff;

        read($self->{'fileMST'}, $buff, 4) || croak "can't read NXTMFN from MST: $!";
        $self->{'NXTMFN'}=unpack("V",$buff) || croak "NXTNFN is zero";

        print STDERR "## self ",Dumper($self),"\n" if ($self->{debug});

        # open files for later
        open($self->{'fileXRF'}, $self->{xrf_file}) || croak "can't open '$self->{xrf_file}': $!";
        binmode($self->{'fileXRF'});

        $self ? return $self : return undef;
}

=head2 count

Return number of records in database

  print $isis->count;

=cut

sub count {
        my $self = shift;
        return $self->{'NXTMFN'} - 1;
}

=head2 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' ],
  };

=cut

sub fetch {
        my $self = shift;

        my $mfn = shift || croak "fetch needs MFN as argument!";

        # is mfn allready in memory?
        my $old_mfn = $self->{'current_mfn'} || -1;
        return $self->{record} if ($mfn == $old_mfn);

        print STDERR "## fetch: $mfn\n" if ($self->{debug});

        # XXX check this?
        my $mfnpos=($mfn+int(($mfn-1)/127))*4;

        print STDERR "## seeking to $mfnpos in file '$self->{xrf_file}'\n" if ($self->{debug});
        seek($self->{'fileXRF'},$mfnpos,0);

        my $buff;

        # delete old record
        delete $self->{record};

        # read XRFMFB abd XRFMFP
        read($self->{'fileXRF'}, $buff, 4);
        my $pointer=unpack("V",$buff);
        if (! $pointer) {
                if ($self->{include_deleted}) {
                        return;
                } else {
                        warn "pointer for MFN $mfn is null\n";
                        return;
                }
        }

        # check for logically deleted record
        if ($pointer & 0x80000000) {
                print STDERR "## record $mfn is logically deleted\n" if ($self->{debug});
                $self->{deleted} = $mfn;

                return unless $self->{include_deleted};

                # abs
                $pointer = ($pointer ^ 0xffffffff) + 1;
        }

        my $XRFMFB = int($pointer/2048);
        my $XRFMFP = $pointer - ($XRFMFB*2048);

        # (XRFMFB - 1) * 512 + XRFMFP
        # why do i have to do XRFMFP % 1024 ?

        my $blk_off = (($XRFMFB - 1) * 512) + ($XRFMFP % 512);

        print STDERR "## pointer: $pointer XRFMFB: $XRFMFB XRFMFP: $XRFMFP offset: $blk_off\n" if ($self->{'debug'});

        # Get Record Information

        seek($self->{'fileMST'},$blk_off,0) || croak "can't seek to $blk_off: $!";

        read($self->{'fileMST'}, $buff, 4) || croak "can't read 4 bytes at offset $blk_off from MST file: $!";
        my $value=unpack("V",$buff);

        print STDERR "## offset for rowid $value is $blk_off (blk $XRFMFB off $XRFMFP)\n" if ($self->{debug});

        if ($value!=$mfn) {
                if ($value == 0) {
                        print STDERR "## record $mfn is physically deleted\n" if ($self->{debug});
                        $self->{deleted} = $mfn;
                        return;
                }

                carp "Error: MFN ".$mfn." not found in MST file, found $value";    
                return;
        }

        read($self->{'fileMST'}, $buff, 14);

        my ($MFRL,$MFBWB,$MFBWP,$BASE,$NVF,$STATUS) = unpack("vVvvvv", $buff);

        print STDERR "## MFRL: $MFRL MFBWB: $MFBWB MFBWP: $MFBWP BASE: $BASE NVF: $NVF STATUS: $STATUS\n" if ($self->{debug});

        warn "MFRL $MFRL is not even number" unless ($MFRL % 2 == 0);

        warn "BASE is not 18+6*NVF" unless ($BASE == 18 + 6 * $NVF);

        # Get Directory Format

        my @FieldPOS;
        my @FieldLEN;
        my @FieldTAG;

        read($self->{'fileMST'}, $buff, 6 * $NVF);

        my $rec_len = 0;

        for (my $i = 0 ; $i < $NVF ; $i++) {

                my ($TAG,$POS,$LEN) = unpack("vvv", substr($buff,$i * 6, 6));

                print STDERR "## TAG: $TAG POS: $POS LEN: $LEN\n" if ($self->{debug});

                # The TAG does not exists in .FDT so we set it to 0.
                #
                # XXX This is removed from perl version; .FDT file is updated manually, so
                # you will often have fields in .MST file which aren't in .FDT. On the other
                # hand, IsisMarc doesn't use .FDT files at all!

                #if (! $self->{TagName}->{$TAG}) {
                #       $TAG=0;
                #}

                push @FieldTAG,$TAG;
                push @FieldPOS,$POS;
                push @FieldLEN,$LEN;

                $rec_len += $LEN;
        }

        # Get Variable Fields

        read($self->{'fileMST'},$buff,$rec_len);

        print STDERR "## rec_len: $rec_len poc: ",tell($self->{'fileMST'})."\n" if ($self->{debug});

        for (my $i = 0 ; $i < $NVF ; $i++) {
                # skip zero-sized fields
                next if ($FieldLEN[$i] == 0);

                push @{$self->{record}->{$FieldTAG[$i]}}, substr($buff,$FieldPOS[$i],$FieldLEN[$i]);
        }

        $self->{'current_mfn'} = $mfn;

        print STDERR Dumper($self),"\n" if ($self->{debug});

        return $self->{'record'};
}

=head2 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 C<read_fdt> is specified when calling C<new> it will display field names
from C<.FDT> file instead of numeric tags.

=cut

sub to_ascii {
        my $self = shift;

        my $mfn = shift || croak "need MFN";

        my $rec = $self->fetch($mfn) || return;

        my $out = "0\t$mfn";

        foreach my $f (sort keys %{$rec}) {
                my $fn = $self->tag_name($f);
                $out .= "\n$fn\t".join("\n$fn\t",@{$self->{record}->{$f}});
        }

        $out .= "\n";

        return $out;
}

=head2 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 C<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, C<i1> and C<i2> like this:

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

This method will also create additional field C<000> with MFN.

=cut

sub to_hash {
        my $self = shift;

        my $mfn = shift || confess "need mfn!";

        # init record to include MFN as field 000
        my $rec = { '000' => [ $mfn ] };

        my $row = $self->fetch($mfn) || return;

        foreach my $k (keys %{$row}) {
                foreach my $l (@{$row->{$k}}) {

                        # filter output
                        if ($self->{'hash_filter'}) {
                                $l = $self->{'hash_filter'}->($l);
                                next unless defined($l);
                        }

                        my $val;

                        # has identifiers?
                        ($val->{'i1'},$val->{'i2'}) = ($1,$2) if ($l =~ s/^([01 #])([01 #])\^/\^/);

                        # has subfields?
                        if ($l =~ m/\^/) {
                                foreach my $t (split(/\^/,$l)) {
                                        next if (! $t);
                                        $val->{substr($t,0,1)} = substr($t,1);
                                }
                        } else {
                                $val = $l;
                        }

                        push @{$rec->{$k}}, $val;
                }
        }

        return $rec;
}

=head2 tag_name

Return name of selected tag

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

=cut

sub tag_name {
        my $self = shift;
        my $tag = shift || return;
        return $self->{'TagName'}->{$tag} || $tag;
}


=head2 read_cnt

Read content of C<.CNT> file and return hash containing it.

  print Dumper($isis->read_cnt);

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

=cut

sub read_cnt  {
        my $self = shift;

        croak "missing CNT file in ",$self->{isisdb} unless ($self->{cnt_file});

        # Get the index information from $db.CNT
   
        open(my $fileCNT, $self->{cnt_file}) || croak "can't read '$self->{cnt_file}': $!";
        binmode($fileCNT);

        my $buff;

        read($fileCNT, $buff, 26) || croak "can't read first table from CNT: $!";
        $self->unpack_cnt($buff);

        read($fileCNT, $buff, 26) || croak "can't read second table from CNT: $!";
        $self->unpack_cnt($buff);

        close($fileCNT);

        return $self->{cnt};
}

=head2 unpack_cnt

Unpack one of two 26 bytes fixed length record in C<.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 C<$self> object under C<cnt> with hash. It's used by C<read_cnt>.

=cut

sub unpack_cnt {
        my $self = shift;

        my @flds = qw(ORDN ORDF N K LIV POSRX NMAXPOS FMAXPOS ABNORMAL);

        my $buff = shift || return;
        my @arr = unpack("vvvvvvVVVv", $buff);

        print STDERR "unpack_cnt: ",join(" ",@arr),"\n" if ($self->{'debug'});

        my $IDTYPE = shift @arr;
        foreach (@flds) {
                $self->{cnt}->{$IDTYPE}->{$_} = abs(shift @arr);
        }
}

1;

=head1 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 C<isis.dll>-based application, but I don't
know any details about it's version.

=head1 AUTHOR

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

This module is based heavily on code from C<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.

=head1 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.


=head1 SEE ALSO

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

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

1	dpavlin	36	package Biblio::Isis;
2	dpavlin	1	use strict;
3
4			use Carp;
5	dpavlin	18	use File::Glob qw(:globally :nocase);
6
7	dpavlin	1	BEGIN {
8			use Exporter ();
9			use vars qw ($VERSION @ISA @EXPORT @EXPORT_OK %EXPORT_TAGS);
10	dpavlin	45	$VERSION = 0.14;
11	dpavlin	1	@ISA = qw (Exporter);
12			#Give a hoot don't pollute, do not export more than needed by default
13			@EXPORT = qw ();
14			@EXPORT_OK = qw ();
15			%EXPORT_TAGS = ();
16
17			}
18
19			=head1 NAME
20
21	dpavlin	36	Biblio::Isis - Read CDS/ISIS, WinISIS and IsisMarc database
22	dpavlin	1
23			=head1 SYNOPSIS
24
25	dpavlin	36	use Biblio::Isis;
26	dpavlin	11
27	dpavlin	36	my $isis = new Biblio::Isis(
28	dpavlin	1	isisdb => './cds/cds',
29			);
30
31	dpavlin	32	for(my $mfn = 1; $mfn <= $isis->count; $mfn++) {
32	dpavlin	11	print $isis->to_ascii($mfn),"\n";
33			}
34
35	dpavlin	1	=head1 DESCRIPTION
36
37	dpavlin	15	This module will read ISIS databases created by DOS CDS/ISIS, WinIsis or
38	dpavlin	27	IsisMarc. It can be used as perl-only alternative to OpenIsis module which
39			seems to depriciate it's old C<XS> bindings for perl.
40	dpavlin	1
41	dpavlin	15	It can create hash values from data in ISIS database (using C<to_hash>),
42			ASCII dump (using C<to_ascii>) or just hash with field names and packed
43			values (like C<^asomething^belse>).
44	dpavlin	11
45			Unique feature of this module is ability to C<include_deleted> records.
46			It will also skip zero sized fields (OpenIsis has a bug in XS bindings, so
47			fields which are zero sized will be filled with random junk from memory).
48
49	dpavlin	15	It also has support for identifiers (only if ISIS database is created by
50			IsisMarc), see C<to_hash>.
51
52	dpavlin	27	This module will always be slower than OpenIsis module which use C
53	dpavlin	15	library. However, since it's written in perl, it's platform independent (so
54			you don't need C compiler), and can be easily modified. I hope that it
55			creates data structures which are easier to use than ones created by
56			OpenIsis, so reduced time in other parts of the code should compensate for
57			slower performance of this module (speed of reading ISIS database is
58			rarely an issue).
59
60	dpavlin	1	=head1 METHODS
61
62			=cut
63
64			# my $ORDN; # Nodes Order
65			# my $ORDF; # Leafs Order
66			# my $N; # Number of Memory buffers for nodes
67			# my $K; # Number of buffers for first level index
68			# my $LIV; # Current number of Index Levels
69			# my $POSRX; # Pointer to Root Record in N0x
70			# my $NMAXPOS; # Next Available position in N0x
71			# my $FMAXPOS; # Next available position in L0x
72			# my $ABNORMAL; # Formal BTree normality indicator
73
74			#
75			# some binary reads
76			#
77
78			=head2 new
79
80	dpavlin	15	Open ISIS database
81	dpavlin	1
82	dpavlin	36	my $isis = new Biblio::Isis(
83	dpavlin	1	isisdb => './cds/cds',
84			read_fdt => 1,
85	dpavlin	12	include_deleted => 1,
86			hash_filter => sub {
87			my $v = shift;
88			$v =~ s#foo#bar#g;
89			},
90	dpavlin	1	debug => 1,
91			);
92
93	dpavlin	2	Options are described below:
94
95			=over 5
96
97	dpavlin	1	=item isisdb
98
99	dpavlin	15	This is full or relative path to ISIS database files which include
100	dpavlin	18	common prefix of C<.MST>, and C<.XRF> and optionally C<.FDT> (if using
101			C<read_fdt> option) files.
102	dpavlin	1
103	dpavlin	15	In this example it uses C<./cds/cds.MST> and related files.
104
105	dpavlin	1	=item read_fdt
106
107			Boolean flag to specify if field definition table should be read. It's off
108			by default.
109
110	dpavlin	9	=item include_deleted
111
112	dpavlin	11	Don't skip logically deleted records in ISIS.
113	dpavlin	9
114	dpavlin	12	=item hash_filter
115
116			Filter code ref which will be used before data is converted to hash.
117
118			=item debug
119
120			Dump a B<lot> of debugging output.
121
122	dpavlin	2	=back
123
124	dpavlin	1	=cut
125
126			sub new {
127			my $class = shift;
128			my $self = {};
129			bless($self, $class);
130
131	dpavlin	9	croak "new needs database name (isisdb) as argument!" unless ({@_}->{isisdb});
132	dpavlin	1
133	dpavlin	12	foreach my $v (qw{isisdb debug include_deleted hash_filter}) {
134	dpavlin	9	$self->{$v} = {@_}->{$v};
135			}
136	dpavlin	1
137	dpavlin	18	my @isis_files = grep(/\.(FDT\|MST\|XRF\|CNT)$/i,glob($self->{isisdb}."*"));
138
139			foreach my $f (@isis_files) {
140			my $ext = $1 if ($f =~ m/\.(\w\w\w)$/);
141			$self->{lc($ext)."_file"} = $f;
142			}
143
144			my @must_exist = qw(mst xrf);
145			push @must_exist, "fdt" if ($self->{read_fdt});
146
147			foreach my $ext (@must_exist) {
148	dpavlin	39	unless ($self->{$ext."_file"}) {
149			carp "missing ",uc($ext)," file in ",$self->{isisdb};
150			return;
151			}
152	dpavlin	18	}
153
154	dpavlin	45	if ($self->{debug}) {
155			print STDERR "## using files: ",join(" ",@isis_files),"\n";
156			eval "use Data::Dump";
157	dpavlin	18
158	dpavlin	45	if (! $@) {
159			Dumper = Data::Dump::dump;
160			} else {
161			use Data::Dumper;
162			}
163			}
164
165	dpavlin	1	# if you want to read .FDT file use read_fdt argument when creating class!
166	dpavlin	18	if ($self->{read_fdt} && -e $self->{fdt_file}) {
167	dpavlin	1
168			# read the $db.FDT file for tags
169			my $fieldzone=0;
170
171	dpavlin	33	open(my $fileFDT, $self->{fdt_file}) \|\| croak "can't read '$self->{fdt_file}': $!";
172			binmode($fileFDT);
173	dpavlin	1
174	dpavlin	33	while (<$fileFDT>) {
175	dpavlin	1	chomp;
176			if ($fieldzone) {
177			my $name=substr($_,0,30);
178			my $tag=substr($_,50,3);
179
180			$name =~ s/\s+$//;
181			$tag =~ s/\s+$//;
182
183			$self->{'TagName'}->{$tag}=$name;
184			}
185
186			if (/^\\\*/) {
187			$fieldzone=1;
188			}
189			}
190
191	dpavlin	33	close($fileFDT);
192	dpavlin	1	}
193
194			# Get the Maximum MFN from $db.MST
195
196	dpavlin	18	open($self->{'fileMST'}, $self->{mst_file}) \|\| croak "can't open '$self->{mst_file}': $!";
197	dpavlin	33	binmode($self->{'fileMST'});
198	dpavlin	1
199			# MST format: (* = 32 bit signed)
200			# CTLMFN* always 0
201			# NXTMFN* MFN to be assigned to the next record created
202			# NXTMFB* last block allocated to master file
203			# NXTMFP offset to next available position in last block
204			# MFTYPE always 0 for user db file (1 for system)
205	dpavlin	34	seek($self->{'fileMST'},4,0) \|\| croak "can't seek to offset 0 in MST: $!";
206	dpavlin	1
207	dpavlin	11	my $buff;
208
209	dpavlin	34	read($self->{'fileMST'}, $buff, 4) \|\| croak "can't read NXTMFN from MST: $!";
210			$self->{'NXTMFN'}=unpack("V",$buff) \|\| croak "NXTNFN is zero";
211	dpavlin	11
212	dpavlin	45	print STDERR "## self ",Dumper($self),"\n" if ($self->{debug});
213	dpavlin	18
214			# open files for later
215			open($self->{'fileXRF'}, $self->{xrf_file}) \|\| croak "can't open '$self->{xrf_file}': $!";
216	dpavlin	33	binmode($self->{'fileXRF'});
217	dpavlin	18
218			$self ? return $self : return undef;
219			}
220
221	dpavlin	32	=head2 count
222
223			Return number of records in database
224
225			print $isis->count;
226
227			=cut
228
229			sub count {
230			my $self = shift;
231			return $self->{'NXTMFN'} - 1;
232			}
233
234	dpavlin	7	=head2 fetch
235	dpavlin	1
236	dpavlin	2	Read record with selected MFN
237	dpavlin	1
238	dpavlin	7	my $rec = $isis->fetch(55);
239	dpavlin	2
240			Returns hash with keys which are field names and values are unpacked values
241	dpavlin	15	for that field like this:
242	dpavlin	2
243	dpavlin	15	$rec = {
244			'210' => [ '^aNew York^cNew York University press^dcop. 1988' ],
245			'990' => [ '2140', '88', 'HAY' ],
246			};
247
248	dpavlin	2	=cut
249
250	dpavlin	7	sub fetch {
251	dpavlin	1	my $self = shift;
252
253	dpavlin	7	my $mfn = shift \|\| croak "fetch needs MFN as argument!";
254	dpavlin	1
255	dpavlin	16	# is mfn allready in memory?
256			my $old_mfn = $self->{'current_mfn'} \|\| -1;
257	dpavlin	25	return $self->{record} if ($mfn == $old_mfn);
258	dpavlin	1
259	dpavlin	16	print STDERR "## fetch: $mfn\n" if ($self->{debug});
260
261	dpavlin	1	# XXX check this?
262			my $mfnpos=($mfn+int(($mfn-1)/127))*4;
263
264	dpavlin	18	print STDERR "## seeking to $mfnpos in file '$self->{xrf_file}'\n" if ($self->{debug});
265	dpavlin	7	seek($self->{'fileXRF'},$mfnpos,0);
266	dpavlin	1
267	dpavlin	11	my $buff;
268
269	dpavlin	25	# delete old record
270			delete $self->{record};
271
272	dpavlin	1	# read XRFMFB abd XRFMFP
273	dpavlin	11	read($self->{'fileXRF'}, $buff, 4);
274	dpavlin	41	my $pointer=unpack("V",$buff);
275			if (! $pointer) {
276			if ($self->{include_deleted}) {
277			return;
278			} else {
279			warn "pointer for MFN $mfn is null\n";
280			return;
281			}
282			}
283	dpavlin	1
284	dpavlin	25	# check for logically deleted record
285	dpavlin	33	if ($pointer & 0x80000000) {
286	dpavlin	25	print STDERR "## record $mfn is logically deleted\n" if ($self->{debug});
287			$self->{deleted} = $mfn;
288
289			return unless $self->{include_deleted};
290
291	dpavlin	33	# abs
292			$pointer = ($pointer ^ 0xffffffff) + 1;
293	dpavlin	25	}
294
295	dpavlin	1	my $XRFMFB = int($pointer/2048);
296			my $XRFMFP = $pointer - ($XRFMFB*2048);
297
298	dpavlin	16	# (XRFMFB - 1) * 512 + XRFMFP
299			# why do i have to do XRFMFP % 1024 ?
300	dpavlin	1
301	dpavlin	26	my $blk_off = (($XRFMFB - 1) * 512) + ($XRFMFP % 512);
302	dpavlin	1
303	dpavlin	16	print STDERR "## pointer: $pointer XRFMFB: $XRFMFB XRFMFP: $XRFMFP offset: $blk_off\n" if ($self->{'debug'});
304	dpavlin	1
305			# Get Record Information
306
307	dpavlin	33	seek($self->{'fileMST'},$blk_off,0) \|\| croak "can't seek to $blk_off: $!";
308	dpavlin	1
309	dpavlin	33	read($self->{'fileMST'}, $buff, 4) \|\| croak "can't read 4 bytes at offset $blk_off from MST file: $!";
310			my $value=unpack("V",$buff);
311	dpavlin	1
312	dpavlin	16	print STDERR "## offset for rowid $value is $blk_off (blk $XRFMFB off $XRFMFP)\n" if ($self->{debug});
313
314	dpavlin	1	if ($value!=$mfn) {
315	dpavlin	26	if ($value == 0) {
316			print STDERR "## record $mfn is physically deleted\n" if ($self->{debug});
317			$self->{deleted} = $mfn;
318			return;
319			}
320
321			carp "Error: MFN ".$mfn." not found in MST file, found $value";
322			return;
323	dpavlin	1	}
324
325	dpavlin	7	read($self->{'fileMST'}, $buff, 14);
326	dpavlin	1
327	dpavlin	33	my ($MFRL,$MFBWB,$MFBWP,$BASE,$NVF,$STATUS) = unpack("vVvvvv", $buff);
328	dpavlin	1
329	dpavlin	16	print STDERR "## MFRL: $MFRL MFBWB: $MFBWB MFBWP: $MFBWP BASE: $BASE NVF: $NVF STATUS: $STATUS\n" if ($self->{debug});
330	dpavlin	1
331	dpavlin	25	warn "MFRL $MFRL is not even number" unless ($MFRL % 2 == 0);
332	dpavlin	9
333	dpavlin	16	warn "BASE is not 18+6NVF" unless ($BASE == 18 + 6 $NVF);
334
335	dpavlin	1	# Get Directory Format
336
337			my @FieldPOS;
338			my @FieldLEN;
339			my @FieldTAG;
340
341	dpavlin	8	read($self->{'fileMST'}, $buff, 6 * $NVF);
342
343	dpavlin	16	my $rec_len = 0;
344	dpavlin	8
345	dpavlin	1	for (my $i = 0 ; $i < $NVF ; $i++) {
346
347	dpavlin	33	my ($TAG,$POS,$LEN) = unpack("vvv", substr($buff,$i * 6, 6));
348	dpavlin	1
349	dpavlin	16	print STDERR "## TAG: $TAG POS: $POS LEN: $LEN\n" if ($self->{debug});
350	dpavlin	1
351			# The TAG does not exists in .FDT so we set it to 0.
352			#
353			# XXX This is removed from perl version; .FDT file is updated manually, so
354			# you will often have fields in .MST file which aren't in .FDT. On the other
355			# hand, IsisMarc doesn't use .FDT files at all!
356
357			#if (! $self->{TagName}->{$TAG}) {
358			# $TAG=0;
359			#}
360
361			push @FieldTAG,$TAG;
362			push @FieldPOS,$POS;
363			push @FieldLEN,$LEN;
364	dpavlin	8
365	dpavlin	16	$rec_len += $LEN;
366	dpavlin	1	}
367
368			# Get Variable Fields
369
370	dpavlin	16	read($self->{'fileMST'},$buff,$rec_len);
371	dpavlin	8
372	dpavlin	16	print STDERR "## rec_len: $rec_len poc: ",tell($self->{'fileMST'})."\n" if ($self->{debug});
373
374	dpavlin	1	for (my $i = 0 ; $i < $NVF ; $i++) {
375	dpavlin	10	# skip zero-sized fields
376			next if ($FieldLEN[$i] == 0);
377
378	dpavlin	8	push @{$self->{record}->{$FieldTAG[$i]}}, substr($buff,$FieldPOS[$i],$FieldLEN[$i]);
379	dpavlin	1	}
380
381	dpavlin	16	$self->{'current_mfn'} = $mfn;
382
383	dpavlin	25	print STDERR Dumper($self),"\n" if ($self->{debug});
384	dpavlin	1
385	dpavlin	2	return $self->{'record'};
386	dpavlin	1	}
387
388	dpavlin	2	=head2 to_ascii
389
390	dpavlin	27	Returns ASCII output of record with specified MFN
391	dpavlin	2
392	dpavlin	15	print $isis->to_ascii(42);
393	dpavlin	2
394	dpavlin	27	This outputs something like this:
395	dpavlin	15
396			210 ^aNew York^cNew York University press^dcop. 1988
397			990 2140
398			990 88
399			990 HAY
400
401			If C<read_fdt> is specified when calling C<new> it will display field names
402			from C<.FDT> file instead of numeric tags.
403
404	dpavlin	2	=cut
405
406			sub to_ascii {
407			my $self = shift;
408
409			my $mfn = shift \|\| croak "need MFN";
410
411	dpavlin	41	my $rec = $self->fetch($mfn) \|\| return;
412	dpavlin	2
413			my $out = "0\t$mfn";
414
415			foreach my $f (sort keys %{$rec}) {
416	dpavlin	15	my $fn = $self->tag_name($f);
417			$out .= "\n$fn\t".join("\n$fn\t",@{$self->{record}->{$f}});
418	dpavlin	2	}
419
420			$out .= "\n";
421
422			return $out;
423			}
424
425	dpavlin	12	=head2 to_hash
426
427	dpavlin	15	Read record with specified MFN and convert it to hash
428	dpavlin	12
429			my $hash = $isis->to_hash($mfn);
430
431	dpavlin	27	It has ability to convert characters (using C<hash_filter>) from ISIS
432	dpavlin	15	database before creating structures enabling character re-mapping or quick
433			fix-up of data.
434	dpavlin	12
435			This function returns hash which is like this:
436
437			$hash = {
438			'210' => [
439			{
440			'c' => 'New York University press',
441			'a' => 'New York',
442			'd' => 'cop. 1988'
443			}
444			],
445			'990' => [
446			'2140',
447			'88',
448			'HAY'
449			],
450			};
451
452	dpavlin	15	You can later use that hash to produce any output from ISIS data.
453	dpavlin	12
454	dpavlin	15	If database is created using IsisMarc, it will also have to special fields
455			which will be used for identifiers, C<i1> and C<i2> like this:
456
457			'200' => [
458			{
459			'i1' => '1',
460			'i2' => ' '
461			'a' => 'Goa',
462			'f' => 'Valdo D\'Arienzo',
463			'e' => 'tipografie e tipografi nel XVI secolo',
464			}
465			],
466
467			This method will also create additional field C<000> with MFN.
468
469	dpavlin	12	=cut
470
471			sub to_hash {
472			my $self = shift;
473
474			my $mfn = shift \|\| confess "need mfn!";
475
476	dpavlin	15	# init record to include MFN as field 000
477	dpavlin	16	my $rec = { '000' => [ $mfn ] };
478	dpavlin	15
479	dpavlin	41	my $row = $self->fetch($mfn) \|\| return;
480	dpavlin	12
481			foreach my $k (keys %{$row}) {
482			foreach my $l (@{$row->{$k}}) {
483
484			# filter output
485	dpavlin	44	if ($self->{'hash_filter'}) {
486			$l = $self->{'hash_filter'}->($l);
487			next unless defined($l);
488			}
489	dpavlin	12
490	dpavlin	15	my $val;
491
492			# has identifiers?
493	dpavlin	23	($val->{'i1'},$val->{'i2'}) = ($1,$2) if ($l =~ s/^([01 #])([01 #])\^/\^/);
494	dpavlin	15
495	dpavlin	12	# has subfields?
496			if ($l =~ m/\^/) {
497			foreach my $t (split(/\^/,$l)) {
498			next if (! $t);
499			$val->{substr($t,0,1)} = substr($t,1);
500			}
501			} else {
502			$val = $l;
503			}
504
505			push @{$rec->{$k}}, $val;
506			}
507			}
508
509			return $rec;
510			}
511
512	dpavlin	15	=head2 tag_name
513	dpavlin	1
514	dpavlin	15	Return name of selected tag
515	dpavlin	1
516	dpavlin	15	print $isis->tag_name('200');
517
518			=cut
519
520			sub tag_name {
521	dpavlin	1	my $self = shift;
522	dpavlin	15	my $tag = shift \|\| return;
523			return $self->{'TagName'}->{$tag} \|\| $tag;
524	dpavlin	1	}
525
526	dpavlin	35
527			=head2 read_cnt
528
529			Read content of C<.CNT> file and return hash containing it.
530
531			print Dumper($isis->read_cnt);
532
533			This function is not used by module (C<.CNT> files are not required for this
534			module to work), but it can be useful to examine your index (while debugging
535			for example).
536
537			=cut
538
539			sub read_cnt {
540			my $self = shift;
541
542			croak "missing CNT file in ",$self->{isisdb} unless ($self->{cnt_file});
543
544			# Get the index information from $db.CNT
545
546			open(my $fileCNT, $self->{cnt_file}) \|\| croak "can't read '$self->{cnt_file}': $!";
547			binmode($fileCNT);
548
549			my $buff;
550
551			read($fileCNT, $buff, 26) \|\| croak "can't read first table from CNT: $!";
552			$self->unpack_cnt($buff);
553
554			read($fileCNT, $buff, 26) \|\| croak "can't read second table from CNT: $!";
555			$self->unpack_cnt($buff);
556
557			close($fileCNT);
558
559			return $self->{cnt};
560			}
561
562			=head2 unpack_cnt
563
564			Unpack one of two 26 bytes fixed length record in C<.CNT> file.
565
566			Here is definition of record:
567
568			off key description size
569			0: IDTYPE BTree type s
570			2: ORDN Nodes Order s
571			4: ORDF Leafs Order s
572			6: N Number of Memory buffers for nodes s
573			8: K Number of buffers for first level index s
574			10: LIV Current number of Index Levels s
575			12: POSRX Pointer to Root Record in N0x l
576			16: NMAXPOS Next Available position in N0x l
577			20: FMAXPOS Next available position in L0x l
578			24: ABNORMAL Formal BTree normality indicator s
579			length: 26 bytes
580
581			This will fill C<$self> object under C<cnt> with hash. It's used by C<read_cnt>.
582
583			=cut
584
585			sub unpack_cnt {
586			my $self = shift;
587
588			my @flds = qw(ORDN ORDF N K LIV POSRX NMAXPOS FMAXPOS ABNORMAL);
589
590			my $buff = shift \|\| return;
591			my @arr = unpack("vvvvvvVVVv", $buff);
592
593			print STDERR "unpack_cnt: ",join(" ",@arr),"\n" if ($self->{'debug'});
594
595			my $IDTYPE = shift @arr;
596			foreach (@flds) {
597			$self->{cnt}->{$IDTYPE}->{$_} = abs(shift @arr);
598			}
599			}
600
601	dpavlin	1	1;
602
603			=head1 BUGS
604
605	dpavlin	27	Some parts of CDS/ISIS documentation are not detailed enough to exmplain
606			some variations in input databases which has been tested with this module.
607			When I was in doubt, I assumed that OpenIsis's implementation was right
608			(except for obvious bugs).
609	dpavlin	1
610	dpavlin	27	However, every effort has been made to test this module with as much
611			databases (and programs that create them) as possible.
612
613			I would be very greatful for success or failure reports about usage of this
614			module with databases from programs other than WinIsis and IsisMarc. I had
615			tested this against ouput of one C<isis.dll>-based application, but I don't
616			know any details about it's version.
617
618	dpavlin	1	=head1 AUTHOR
619
620			Dobrica Pavlinusic
621			CPAN ID: DPAVLIN
622			dpavlin@rot13.org
623			http://www.rot13.org/~dpavlin/
624
625	dpavlin	15	This module is based heavily on code from C<LIBISIS.PHP> library to read ISIS files V0.1.1
626			written in php and (c) 2000 Franck Martin <franck@sopac.org> and released under LGPL.
627	dpavlin	1
628			=head1 COPYRIGHT
629
630			This program is free software; you can redistribute
631			it and/or modify it under the same terms as Perl itself.
632
633			The full text of the license can be found in the
634			LICENSE file included with this module.
635
636
637			=head1 SEE ALSO
638
639	dpavlin	15	OpenIsis web site L<http://www.openisis.org>
640	dpavlin	1
641	dpavlin	15	perl4lib site L<http://perl4lib.perl.org>
642