/[Biblio-Isis]/trunk/lib/Biblio/Isis.pm
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Revision 39 - (show annotations)
Thu Jan 27 22:01:17 2005 UTC (18 years ago) by dpavlin
File size: 14885 byte(s)
carp and not croak if MST or XRF file isn't found (calling program will
receive undef from new and warning will be issued).

1 package Biblio::Isis;
2 use strict;
3
4 use Carp;
5 use File::Glob qw(:globally :nocase);
6
7 use Data::Dumper;
8
9 BEGIN {
10 use Exporter ();
11 use vars qw ($VERSION @ISA @EXPORT @EXPORT_OK %EXPORT_TAGS);
12 $VERSION = 0.12;
13 @ISA = qw (Exporter);
14 #Give a hoot don't pollute, do not export more than needed by default
15 @EXPORT = qw ();
16 @EXPORT_OK = qw ();
17 %EXPORT_TAGS = ();
18
19 }
20
21 =head1 NAME
22
23 Biblio::Isis - Read CDS/ISIS, WinISIS and IsisMarc database
24
25 =head1 SYNOPSIS
26
27 use Biblio::Isis;
28
29 my $isis = new Biblio::Isis(
30 isisdb => './cds/cds',
31 );
32
33 for(my $mfn = 1; $mfn <= $isis->count; $mfn++) {
34 print $isis->to_ascii($mfn),"\n";
35 }
36
37 =head1 DESCRIPTION
38
39 This module will read ISIS databases created by DOS CDS/ISIS, WinIsis or
40 IsisMarc. It can be used as perl-only alternative to OpenIsis module which
41 seems to depriciate it's old C<XS> bindings for perl.
42
43 It can create hash values from data in ISIS database (using C<to_hash>),
44 ASCII dump (using C<to_ascii>) or just hash with field names and packed
45 values (like C<^asomething^belse>).
46
47 Unique feature of this module is ability to C<include_deleted> records.
48 It will also skip zero sized fields (OpenIsis has a bug in XS bindings, so
49 fields which are zero sized will be filled with random junk from memory).
50
51 It also has support for identifiers (only if ISIS database is created by
52 IsisMarc), see C<to_hash>.
53
54 This module will always be slower than OpenIsis module which use C
55 library. However, since it's written in perl, it's platform independent (so
56 you don't need C compiler), and can be easily modified. I hope that it
57 creates data structures which are easier to use than ones created by
58 OpenIsis, so reduced time in other parts of the code should compensate for
59 slower performance of this module (speed of reading ISIS database is
60 rarely an issue).
61
62 =head1 METHODS
63
64 =cut
65
66 # my $ORDN; # Nodes Order
67 # my $ORDF; # Leafs Order
68 # my $N; # Number of Memory buffers for nodes
69 # my $K; # Number of buffers for first level index
70 # my $LIV; # Current number of Index Levels
71 # my $POSRX; # Pointer to Root Record in N0x
72 # my $NMAXPOS; # Next Available position in N0x
73 # my $FMAXPOS; # Next available position in L0x
74 # my $ABNORMAL; # Formal BTree normality indicator
75
76 #
77 # some binary reads
78 #
79
80 =head2 new
81
82 Open ISIS database
83
84 my $isis = new Biblio::Isis(
85 isisdb => './cds/cds',
86 read_fdt => 1,
87 include_deleted => 1,
88 hash_filter => sub {
89 my $v = shift;
90 $v =~ s#foo#bar#g;
91 },
92 debug => 1,
93 );
94
95 Options are described below:
96
97 =over 5
98
99 =item isisdb
100
101 This is full or relative path to ISIS database files which include
102 common prefix of C<.MST>, and C<.XRF> and optionally C<.FDT> (if using
103 C<read_fdt> option) files.
104
105 In this example it uses C<./cds/cds.MST> and related files.
106
107 =item read_fdt
108
109 Boolean flag to specify if field definition table should be read. It's off
110 by default.
111
112 =item include_deleted
113
114 Don't skip logically deleted records in ISIS.
115
116 =item hash_filter
117
118 Filter code ref which will be used before data is converted to hash.
119
120 =item debug
121
122 Dump a B<lot> of debugging output.
123
124 =back
125
126 =cut
127
128 sub new {
129 my $class = shift;
130 my $self = {};
131 bless($self, $class);
132
133 croak "new needs database name (isisdb) as argument!" unless ({@_}->{isisdb});
134
135 foreach my $v (qw{isisdb debug include_deleted hash_filter}) {
136 $self->{$v} = {@_}->{$v};
137 }
138
139 my @isis_files = grep(/\.(FDT|MST|XRF|CNT)$/i,glob($self->{isisdb}."*"));
140
141 foreach my $f (@isis_files) {
142 my $ext = $1 if ($f =~ m/\.(\w\w\w)$/);
143 $self->{lc($ext)."_file"} = $f;
144 }
145
146 my @must_exist = qw(mst xrf);
147 push @must_exist, "fdt" if ($self->{read_fdt});
148
149 foreach my $ext (@must_exist) {
150 unless ($self->{$ext."_file"}) {
151 carp "missing ",uc($ext)," file in ",$self->{isisdb};
152 return;
153 }
154 }
155
156 print STDERR "## using files: ",join(" ",@isis_files),"\n" if ($self->{debug});
157
158 # if you want to read .FDT file use read_fdt argument when creating class!
159 if ($self->{read_fdt} && -e $self->{fdt_file}) {
160
161 # read the $db.FDT file for tags
162 my $fieldzone=0;
163
164 open(my $fileFDT, $self->{fdt_file}) || croak "can't read '$self->{fdt_file}': $!";
165 binmode($fileFDT);
166
167 while (<$fileFDT>) {
168 chomp;
169 if ($fieldzone) {
170 my $name=substr($_,0,30);
171 my $tag=substr($_,50,3);
172
173 $name =~ s/\s+$//;
174 $tag =~ s/\s+$//;
175
176 $self->{'TagName'}->{$tag}=$name;
177 }
178
179 if (/^\*\*\*/) {
180 $fieldzone=1;
181 }
182 }
183
184 close($fileFDT);
185 }
186
187 # Get the Maximum MFN from $db.MST
188
189 open($self->{'fileMST'}, $self->{mst_file}) || croak "can't open '$self->{mst_file}': $!";
190 binmode($self->{'fileMST'});
191
192 # MST format: (* = 32 bit signed)
193 # CTLMFN* always 0
194 # NXTMFN* MFN to be assigned to the next record created
195 # NXTMFB* last block allocated to master file
196 # NXTMFP offset to next available position in last block
197 # MFTYPE always 0 for user db file (1 for system)
198 seek($self->{'fileMST'},4,0) || croak "can't seek to offset 0 in MST: $!";
199
200 my $buff;
201
202 read($self->{'fileMST'}, $buff, 4) || croak "can't read NXTMFN from MST: $!";
203 $self->{'NXTMFN'}=unpack("V",$buff) || croak "NXTNFN is zero";
204
205 print STDERR Dumper($self),"\n" if ($self->{debug});
206
207 # open files for later
208 open($self->{'fileXRF'}, $self->{xrf_file}) || croak "can't open '$self->{xrf_file}': $!";
209 binmode($self->{'fileXRF'});
210
211 $self ? return $self : return undef;
212 }
213
214 =head2 count
215
216 Return number of records in database
217
218 print $isis->count;
219
220 =cut
221
222 sub count {
223 my $self = shift;
224 return $self->{'NXTMFN'} - 1;
225 }
226
227 =head2 fetch
228
229 Read record with selected MFN
230
231 my $rec = $isis->fetch(55);
232
233 Returns hash with keys which are field names and values are unpacked values
234 for that field like this:
235
236 $rec = {
237 '210' => [ '^aNew York^cNew York University press^dcop. 1988' ],
238 '990' => [ '2140', '88', 'HAY' ],
239 };
240
241 =cut
242
243 sub fetch {
244 my $self = shift;
245
246 my $mfn = shift || croak "fetch needs MFN as argument!";
247
248 # is mfn allready in memory?
249 my $old_mfn = $self->{'current_mfn'} || -1;
250 return $self->{record} if ($mfn == $old_mfn);
251
252 print STDERR "## fetch: $mfn\n" if ($self->{debug});
253
254 # XXX check this?
255 my $mfnpos=($mfn+int(($mfn-1)/127))*4;
256
257 print STDERR "## seeking to $mfnpos in file '$self->{xrf_file}'\n" if ($self->{debug});
258 seek($self->{'fileXRF'},$mfnpos,0);
259
260 my $buff;
261
262 # delete old record
263 delete $self->{record};
264
265 # read XRFMFB abd XRFMFP
266 read($self->{'fileXRF'}, $buff, 4);
267 my $pointer=unpack("V",$buff) || croak "pointer is null";
268
269 # check for logically deleted record
270 if ($pointer & 0x80000000) {
271 print STDERR "## record $mfn is logically deleted\n" if ($self->{debug});
272 $self->{deleted} = $mfn;
273
274 return unless $self->{include_deleted};
275
276 # abs
277 $pointer = ($pointer ^ 0xffffffff) + 1;
278 }
279
280 my $XRFMFB = int($pointer/2048);
281 my $XRFMFP = $pointer - ($XRFMFB*2048);
282
283 # (XRFMFB - 1) * 512 + XRFMFP
284 # why do i have to do XRFMFP % 1024 ?
285
286 my $blk_off = (($XRFMFB - 1) * 512) + ($XRFMFP % 512);
287
288 print STDERR "## pointer: $pointer XRFMFB: $XRFMFB XRFMFP: $XRFMFP offset: $blk_off\n" if ($self->{'debug'});
289
290 # Get Record Information
291
292 seek($self->{'fileMST'},$blk_off,0) || croak "can't seek to $blk_off: $!";
293
294 read($self->{'fileMST'}, $buff, 4) || croak "can't read 4 bytes at offset $blk_off from MST file: $!";
295 my $value=unpack("V",$buff);
296
297 print STDERR "## offset for rowid $value is $blk_off (blk $XRFMFB off $XRFMFP)\n" if ($self->{debug});
298
299 if ($value!=$mfn) {
300 if ($value == 0) {
301 print STDERR "## record $mfn is physically deleted\n" if ($self->{debug});
302 $self->{deleted} = $mfn;
303 return;
304 }
305
306 carp "Error: MFN ".$mfn." not found in MST file, found $value";
307 return;
308 }
309
310 read($self->{'fileMST'}, $buff, 14);
311
312 my ($MFRL,$MFBWB,$MFBWP,$BASE,$NVF,$STATUS) = unpack("vVvvvv", $buff);
313
314 print STDERR "## MFRL: $MFRL MFBWB: $MFBWB MFBWP: $MFBWP BASE: $BASE NVF: $NVF STATUS: $STATUS\n" if ($self->{debug});
315
316 warn "MFRL $MFRL is not even number" unless ($MFRL % 2 == 0);
317
318 warn "BASE is not 18+6*NVF" unless ($BASE == 18 + 6 * $NVF);
319
320 # Get Directory Format
321
322 my @FieldPOS;
323 my @FieldLEN;
324 my @FieldTAG;
325
326 read($self->{'fileMST'}, $buff, 6 * $NVF);
327
328 my $rec_len = 0;
329
330 for (my $i = 0 ; $i < $NVF ; $i++) {
331
332 my ($TAG,$POS,$LEN) = unpack("vvv", substr($buff,$i * 6, 6));
333
334 print STDERR "## TAG: $TAG POS: $POS LEN: $LEN\n" if ($self->{debug});
335
336 # The TAG does not exists in .FDT so we set it to 0.
337 #
338 # XXX This is removed from perl version; .FDT file is updated manually, so
339 # you will often have fields in .MST file which aren't in .FDT. On the other
340 # hand, IsisMarc doesn't use .FDT files at all!
341
342 #if (! $self->{TagName}->{$TAG}) {
343 # $TAG=0;
344 #}
345
346 push @FieldTAG,$TAG;
347 push @FieldPOS,$POS;
348 push @FieldLEN,$LEN;
349
350 $rec_len += $LEN;
351 }
352
353 # Get Variable Fields
354
355 read($self->{'fileMST'},$buff,$rec_len);
356
357 print STDERR "## rec_len: $rec_len poc: ",tell($self->{'fileMST'})."\n" if ($self->{debug});
358
359 for (my $i = 0 ; $i < $NVF ; $i++) {
360 # skip zero-sized fields
361 next if ($FieldLEN[$i] == 0);
362
363 push @{$self->{record}->{$FieldTAG[$i]}}, substr($buff,$FieldPOS[$i],$FieldLEN[$i]);
364 }
365
366 $self->{'current_mfn'} = $mfn;
367
368 print STDERR Dumper($self),"\n" if ($self->{debug});
369
370 return $self->{'record'};
371 }
372
373 =head2 to_ascii
374
375 Returns ASCII output of record with specified MFN
376
377 print $isis->to_ascii(42);
378
379 This outputs something like this:
380
381 210 ^aNew York^cNew York University press^dcop. 1988
382 990 2140
383 990 88
384 990 HAY
385
386 If C<read_fdt> is specified when calling C<new> it will display field names
387 from C<.FDT> file instead of numeric tags.
388
389 =cut
390
391 sub to_ascii {
392 my $self = shift;
393
394 my $mfn = shift || croak "need MFN";
395
396 my $rec = $self->fetch($mfn);
397
398 my $out = "0\t$mfn";
399
400 foreach my $f (sort keys %{$rec}) {
401 my $fn = $self->tag_name($f);
402 $out .= "\n$fn\t".join("\n$fn\t",@{$self->{record}->{$f}});
403 }
404
405 $out .= "\n";
406
407 return $out;
408 }
409
410 =head2 to_hash
411
412 Read record with specified MFN and convert it to hash
413
414 my $hash = $isis->to_hash($mfn);
415
416 It has ability to convert characters (using C<hash_filter>) from ISIS
417 database before creating structures enabling character re-mapping or quick
418 fix-up of data.
419
420 This function returns hash which is like this:
421
422 $hash = {
423 '210' => [
424 {
425 'c' => 'New York University press',
426 'a' => 'New York',
427 'd' => 'cop. 1988'
428 }
429 ],
430 '990' => [
431 '2140',
432 '88',
433 'HAY'
434 ],
435 };
436
437 You can later use that hash to produce any output from ISIS data.
438
439 If database is created using IsisMarc, it will also have to special fields
440 which will be used for identifiers, C<i1> and C<i2> like this:
441
442 '200' => [
443 {
444 'i1' => '1',
445 'i2' => ' '
446 'a' => 'Goa',
447 'f' => 'Valdo D\'Arienzo',
448 'e' => 'tipografie e tipografi nel XVI secolo',
449 }
450 ],
451
452 This method will also create additional field C<000> with MFN.
453
454 =cut
455
456 sub to_hash {
457 my $self = shift;
458
459 my $mfn = shift || confess "need mfn!";
460
461 # init record to include MFN as field 000
462 my $rec = { '000' => [ $mfn ] };
463
464 my $row = $self->fetch($mfn);
465
466 foreach my $k (keys %{$row}) {
467 foreach my $l (@{$row->{$k}}) {
468
469 # filter output
470 $l = $self->{'hash_filter'}->($l) if ($self->{'hash_filter'});
471
472 my $val;
473
474 # has identifiers?
475 ($val->{'i1'},$val->{'i2'}) = ($1,$2) if ($l =~ s/^([01 #])([01 #])\^/\^/);
476
477 # has subfields?
478 if ($l =~ m/\^/) {
479 foreach my $t (split(/\^/,$l)) {
480 next if (! $t);
481 $val->{substr($t,0,1)} = substr($t,1);
482 }
483 } else {
484 $val = $l;
485 }
486
487 push @{$rec->{$k}}, $val;
488 }
489 }
490
491 return $rec;
492 }
493
494 =head2 tag_name
495
496 Return name of selected tag
497
498 print $isis->tag_name('200');
499
500 =cut
501
502 sub tag_name {
503 my $self = shift;
504 my $tag = shift || return;
505 return $self->{'TagName'}->{$tag} || $tag;
506 }
507
508
509 =head2 read_cnt
510
511 Read content of C<.CNT> file and return hash containing it.
512
513 print Dumper($isis->read_cnt);
514
515 This function is not used by module (C<.CNT> files are not required for this
516 module to work), but it can be useful to examine your index (while debugging
517 for example).
518
519 =cut
520
521 sub read_cnt {
522 my $self = shift;
523
524 croak "missing CNT file in ",$self->{isisdb} unless ($self->{cnt_file});
525
526 # Get the index information from $db.CNT
527
528 open(my $fileCNT, $self->{cnt_file}) || croak "can't read '$self->{cnt_file}': $!";
529 binmode($fileCNT);
530
531 my $buff;
532
533 read($fileCNT, $buff, 26) || croak "can't read first table from CNT: $!";
534 $self->unpack_cnt($buff);
535
536 read($fileCNT, $buff, 26) || croak "can't read second table from CNT: $!";
537 $self->unpack_cnt($buff);
538
539 close($fileCNT);
540
541 return $self->{cnt};
542 }
543
544 =head2 unpack_cnt
545
546 Unpack one of two 26 bytes fixed length record in C<.CNT> file.
547
548 Here is definition of record:
549
550 off key description size
551 0: IDTYPE BTree type s
552 2: ORDN Nodes Order s
553 4: ORDF Leafs Order s
554 6: N Number of Memory buffers for nodes s
555 8: K Number of buffers for first level index s
556 10: LIV Current number of Index Levels s
557 12: POSRX Pointer to Root Record in N0x l
558 16: NMAXPOS Next Available position in N0x l
559 20: FMAXPOS Next available position in L0x l
560 24: ABNORMAL Formal BTree normality indicator s
561 length: 26 bytes
562
563 This will fill C<$self> object under C<cnt> with hash. It's used by C<read_cnt>.
564
565 =cut
566
567 sub unpack_cnt {
568 my $self = shift;
569
570 my @flds = qw(ORDN ORDF N K LIV POSRX NMAXPOS FMAXPOS ABNORMAL);
571
572 my $buff = shift || return;
573 my @arr = unpack("vvvvvvVVVv", $buff);
574
575 print STDERR "unpack_cnt: ",join(" ",@arr),"\n" if ($self->{'debug'});
576
577 my $IDTYPE = shift @arr;
578 foreach (@flds) {
579 $self->{cnt}->{$IDTYPE}->{$_} = abs(shift @arr);
580 }
581 }
582
583 1;
584
585 =head1 BUGS
586
587 Some parts of CDS/ISIS documentation are not detailed enough to exmplain
588 some variations in input databases which has been tested with this module.
589 When I was in doubt, I assumed that OpenIsis's implementation was right
590 (except for obvious bugs).
591
592 However, every effort has been made to test this module with as much
593 databases (and programs that create them) as possible.
594
595 I would be very greatful for success or failure reports about usage of this
596 module with databases from programs other than WinIsis and IsisMarc. I had
597 tested this against ouput of one C<isis.dll>-based application, but I don't
598 know any details about it's version.
599
600 =head1 AUTHOR
601
602 Dobrica Pavlinusic
603 CPAN ID: DPAVLIN
604 dpavlin@rot13.org
605 http://www.rot13.org/~dpavlin/
606
607 This module is based heavily on code from C<LIBISIS.PHP> library to read ISIS files V0.1.1
608 written in php and (c) 2000 Franck Martin <franck@sopac.org> and released under LGPL.
609
610 =head1 COPYRIGHT
611
612 This program is free software; you can redistribute
613 it and/or modify it under the same terms as Perl itself.
614
615 The full text of the license can be found in the
616 LICENSE file included with this module.
617
618
619 =head1 SEE ALSO
620
621 OpenIsis web site L<http://www.openisis.org>
622
623 perl4lib site L<http://perl4lib.perl.org>
624

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