1 |
package WebPAC::Input; |
2 |
|
3 |
use warnings; |
4 |
use strict; |
5 |
|
6 |
use blib; |
7 |
|
8 |
use WebPAC::Common; |
9 |
use base qw/WebPAC::Common/; |
10 |
use Data::Dumper; |
11 |
use Encode qw/from_to/; |
12 |
|
13 |
=head1 NAME |
14 |
|
15 |
WebPAC::Input - read different file formats into WebPAC |
16 |
|
17 |
=head1 VERSION |
18 |
|
19 |
Version 0.12 |
20 |
|
21 |
=cut |
22 |
|
23 |
our $VERSION = '0.12'; |
24 |
|
25 |
=head1 SYNOPSIS |
26 |
|
27 |
This module implements input as database which have fixed and known |
28 |
I<size> while indexing and single unique numeric identifier for database |
29 |
position ranging from 1 to I<size>. |
30 |
|
31 |
Simply, something that is indexed by unmber from 1 .. I<size>. |
32 |
|
33 |
Examples of such databases are CDS/ISIS files, MARC files, lines in |
34 |
text file, and so on. |
35 |
|
36 |
Specific file formats are implemented using low-level interface modules, |
37 |
located in C<WebPAC::Input::*> namespace which export C<open_db>, |
38 |
C<fetch_rec> and optional C<init> functions. |
39 |
|
40 |
Perhaps a little code snippet. |
41 |
|
42 |
use WebPAC::Input; |
43 |
|
44 |
my $db = WebPAC::Input->new( |
45 |
module => 'WebPAC::Input::ISIS', |
46 |
low_mem => 1, |
47 |
); |
48 |
|
49 |
$db->open( path => '/path/to/database' ); |
50 |
print "database size: ",$db->size,"\n"; |
51 |
while (my $rec = $db->fetch) { |
52 |
# do something with $rec |
53 |
} |
54 |
|
55 |
|
56 |
|
57 |
=head1 FUNCTIONS |
58 |
|
59 |
=head2 new |
60 |
|
61 |
Create new input database object. |
62 |
|
63 |
my $db = new WebPAC::Input( |
64 |
module => 'WebPAC::Input::MARC', |
65 |
encoding => 'ISO-8859-2', |
66 |
low_mem => 1, |
67 |
recode => 'char pairs', |
68 |
no_progress_bar => 1, |
69 |
); |
70 |
|
71 |
C<module> is low-level file format module. See L<WebPAC::Input::ISIS> and |
72 |
L<WebPAC::Input::MARC>. |
73 |
|
74 |
Optional parametar C<encoding> specify application code page (which will be |
75 |
used internally). This should probably be your terminal encoding, and by |
76 |
default, it C<ISO-8859-2>. |
77 |
|
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Default is not to use C<low_mem> options (see L<MEMORY USAGE> below). |
79 |
|
80 |
C<recode> is optional string constisting of character or words pairs that |
81 |
should be replaced in input stream. |
82 |
|
83 |
C<no_progress_bar> disables progress bar output on C<STDOUT> |
84 |
|
85 |
This function will also call low-level C<init> if it exists with same |
86 |
parametars. |
87 |
|
88 |
=cut |
89 |
|
90 |
sub new { |
91 |
my $class = shift; |
92 |
my $self = {@_}; |
93 |
bless($self, $class); |
94 |
|
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my $log = $self->_get_logger; |
96 |
|
97 |
$log->logconfess("code_page argument is not suppored any more. change it to encoding") if ($self->{lookup}); |
98 |
$log->logconfess("lookup argument is not suppored any more. rewrite call to lookup_ref") if ($self->{lookup}); |
99 |
|
100 |
$log->logconfess("specify low-level file format module") unless ($self->{module}); |
101 |
my $module = $self->{module}; |
102 |
$module =~ s#::#/#g; |
103 |
$module .= '.pm'; |
104 |
$log->debug("require low-level module $self->{module} from $module"); |
105 |
|
106 |
require $module; |
107 |
#eval $self->{module} .'->import'; |
108 |
|
109 |
# check if required subclasses are implemented |
110 |
foreach my $subclass (qw/open_db fetch_rec init/) { |
111 |
my $n = $self->{module} . '::' . $subclass; |
112 |
if (! defined &{ $n }) { |
113 |
my $missing = "missing $subclass in $self->{module}"; |
114 |
$self->{$subclass} = sub { $log->logwarn($missing) }; |
115 |
} else { |
116 |
$self->{$subclass} = \&{ $n }; |
117 |
} |
118 |
} |
119 |
|
120 |
if ($self->{init}) { |
121 |
$log->debug("calling init"); |
122 |
$self->{init}->($self, @_); |
123 |
} |
124 |
|
125 |
$self->{'encoding'} ||= 'ISO-8859-2'; |
126 |
|
127 |
# running with low_mem flag? well, use DBM::Deep then. |
128 |
if ($self->{'low_mem'}) { |
129 |
$log->info("running with low_mem which impacts performance (<32 Mb memory usage)"); |
130 |
|
131 |
my $db_file = "data.db"; |
132 |
|
133 |
if (-e $db_file) { |
134 |
unlink $db_file or $log->logdie("can't remove '$db_file' from last run"); |
135 |
$log->debug("removed '$db_file' from last run"); |
136 |
} |
137 |
|
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require DBM::Deep; |
139 |
|
140 |
my $db = new DBM::Deep $db_file; |
141 |
|
142 |
$log->logdie("DBM::Deep error: $!") unless ($db); |
143 |
|
144 |
if ($db->error()) { |
145 |
$log->logdie("can't open '$db_file' under low_mem: ",$db->error()); |
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} else { |
147 |
$log->debug("using file '$db_file' for DBM::Deep"); |
148 |
} |
149 |
|
150 |
$self->{'db'} = $db; |
151 |
} |
152 |
|
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$self ? return $self : return undef; |
154 |
} |
155 |
|
156 |
=head2 open |
157 |
|
158 |
This function will read whole database in memory and produce lookups. |
159 |
|
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$input->open( |
161 |
path => '/path/to/database/file', |
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code_page => 'cp852', |
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limit => 500, |
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offset => 6000, |
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lookup => $lookup_obj, |
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stats => 1, |
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lookup_ref => sub { |
168 |
my ($k,$v) = @_; |
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# store lookup $k => $v |
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}, |
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modify_records => { |
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900 => { '^a' => { ' : ' => '^b' } }, |
173 |
901 => { '*' => { '^b' => ' ; ' } }, |
174 |
}, |
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modify_file => 'conf/modify/mapping.map', |
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); |
177 |
|
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By default, C<code_page> is assumed to be C<cp852>. |
179 |
|
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C<offset> is optional parametar to position at some offset before reading from database. |
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|
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C<limit> is optional parametar to read just C<limit> records from database |
183 |
|
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C<stats> create optional report about usage of fields and subfields |
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|
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C<lookup_coderef> is closure to call when adding C<< key => 'value' >> combinations to |
187 |
lookup. |
188 |
|
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C<modify_records> specify mapping from subfields to delimiters or from |
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delimiters to subfields, as well as oprations on fields (if subfield is |
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defined as C<*>. |
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|
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C<modify_file> is alternative for C<modify_records> above which preserves order and offers |
194 |
(hopefully) simplier sintax than YAML or perl (see L</modify_file_regex>). This option |
195 |
overrides C<modify_records> if both exists for same input. |
196 |
|
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Returns size of database, regardless of C<offset> and C<limit> |
198 |
parametars, see also C<size>. |
199 |
|
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=cut |
201 |
|
202 |
sub open { |
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my $self = shift; |
204 |
my $arg = {@_}; |
205 |
|
206 |
my $log = $self->_get_logger(); |
207 |
|
208 |
$log->logconfess("lookup argument is not suppored any more. rewrite call to lookup_coderef") if ($arg->{lookup}); |
209 |
$log->logconfess("lookup_coderef must be CODE, not ",ref($arg->{lookup_coderef})) |
210 |
if ($arg->{lookup_coderef} && ref($arg->{lookup_coderef}) ne 'CODE'); |
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|
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$log->logcroak("need path") if (! $arg->{'path'}); |
213 |
my $code_page = $arg->{'code_page'} || 'cp852'; |
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|
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# store data in object |
216 |
$self->{'input_code_page'} = $code_page; |
217 |
foreach my $v (qw/path offset limit/) { |
218 |
$self->{$v} = $arg->{$v} if ($arg->{$v}); |
219 |
} |
220 |
|
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my $filter_ref; |
222 |
my $recode_regex; |
223 |
my $recode_map; |
224 |
|
225 |
if ($self->{recode}) { |
226 |
my @r = split(/\s/, $self->{recode}); |
227 |
if ($#r % 2 != 1) { |
228 |
$log->logwarn("recode needs even number of elements (some number of valid pairs)"); |
229 |
} else { |
230 |
while (@r) { |
231 |
my $from = shift @r; |
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my $to = shift @r; |
233 |
$recode_map->{$from} = $to; |
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} |
235 |
|
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$recode_regex = join '|' => keys %{ $recode_map }; |
237 |
|
238 |
$log->debug("using recode regex: $recode_regex"); |
239 |
} |
240 |
|
241 |
} |
242 |
|
243 |
my $rec_regex; |
244 |
if (my $p = $arg->{modify_file}) { |
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$log->debug("using modify_file $p"); |
246 |
$rec_regex = $self->modify_file_regexps( $p ); |
247 |
} elsif (my $h = $arg->{modify_records}) { |
248 |
$log->debug("using modify_records ", Dumper( $h )); |
249 |
$rec_regex = $self->modify_record_regexps(%{ $h }); |
250 |
} |
251 |
$log->debug("rec_regex: ", Dumper($rec_regex)) if ($rec_regex); |
252 |
|
253 |
my ($db, $size) = $self->{open_db}->( $self, |
254 |
path => $arg->{path}, |
255 |
# filter => sub { |
256 |
# my ($l,$f_nr) = @_; |
257 |
# return unless defined($l); |
258 |
# from_to($l, $code_page, $self->{'encoding'}); |
259 |
# $l =~ s/($recode_regex)/$recode_map->{$1}/g if ($recode_regex && $recode_map); |
260 |
# return $l; |
261 |
# }, |
262 |
%{ $arg }, |
263 |
); |
264 |
|
265 |
unless (defined($db)) { |
266 |
$log->logwarn("can't open database $arg->{path}, skipping..."); |
267 |
return; |
268 |
} |
269 |
|
270 |
unless ($size) { |
271 |
$log->logwarn("no records in database $arg->{path}, skipping..."); |
272 |
return; |
273 |
} |
274 |
|
275 |
my $from_rec = 1; |
276 |
my $to_rec = $size; |
277 |
|
278 |
if (my $s = $self->{offset}) { |
279 |
$log->debug("skipping to MFN $s"); |
280 |
$from_rec = $s; |
281 |
} else { |
282 |
$self->{offset} = $from_rec; |
283 |
} |
284 |
|
285 |
if ($self->{limit}) { |
286 |
$log->debug("limiting to ",$self->{limit}," records"); |
287 |
$to_rec = $from_rec + $self->{limit} - 1; |
288 |
$to_rec = $size if ($to_rec > $size); |
289 |
} |
290 |
|
291 |
# store size for later |
292 |
$self->{size} = ($to_rec - $from_rec) ? ($to_rec - $from_rec + 1) : 0; |
293 |
|
294 |
$log->info("processing $self->{size}/$size records [$from_rec-$to_rec] convert $code_page -> $self->{encoding}", $self->{stats} ? ' [stats]' : ''); |
295 |
|
296 |
# read database |
297 |
for (my $pos = $from_rec; $pos <= $to_rec; $pos++) { |
298 |
|
299 |
$log->debug("position: $pos\n"); |
300 |
|
301 |
my $rec = $self->{fetch_rec}->($self, $db, $pos, sub { |
302 |
my ($l,$f_nr) = @_; |
303 |
# return unless defined($l); |
304 |
# return $l unless ($rec_regex && $f_nr); |
305 |
|
306 |
$log->debug("-=> $f_nr ## $l"); |
307 |
|
308 |
# codepage conversion and recode_regex |
309 |
from_to($l, $code_page, $self->{'encoding'}); |
310 |
$l =~ s/($recode_regex)/$recode_map->{$1}/g if ($recode_regex && $recode_map); |
311 |
|
312 |
# apply regexps |
313 |
if ($rec_regex && defined($rec_regex->{$f_nr})) { |
314 |
$log->logconfess("regexps->{$f_nr} must be ARRAY") if (ref($rec_regex->{$f_nr}) ne 'ARRAY'); |
315 |
my $c = 0; |
316 |
foreach my $r (@{ $rec_regex->{$f_nr} }) { |
317 |
my $old_l = $l; |
318 |
eval '$l =~ ' . $r; |
319 |
if ($old_l ne $l) { |
320 |
$log->debug("REGEX on $f_nr eval \$l =~ $r\n## old l: [$old_l]\n## new l: [$l]"); |
321 |
} |
322 |
$log->error("error applying regex: $r") if ($@); |
323 |
} |
324 |
} |
325 |
|
326 |
$log->debug("<=- $f_nr ## $l"); |
327 |
return $l; |
328 |
}); |
329 |
|
330 |
$log->debug(sub { Dumper($rec) }); |
331 |
|
332 |
if (! $rec) { |
333 |
$log->warn("record $pos empty? skipping..."); |
334 |
next; |
335 |
} |
336 |
|
337 |
# store |
338 |
if ($self->{low_mem}) { |
339 |
$self->{db}->put($pos, $rec); |
340 |
} else { |
341 |
$self->{data}->{$pos} = $rec; |
342 |
} |
343 |
|
344 |
# create lookup |
345 |
$arg->{'lookup_coderef'}->( $rec ) if ($rec && $arg->{'lookup_coderef'}); |
346 |
|
347 |
# update counters for statistics |
348 |
if ($self->{stats}) { |
349 |
|
350 |
# fetch clean record with regexpes applied for statistics |
351 |
my $rec = $self->{fetch_rec}->($self, $db, $pos); |
352 |
|
353 |
foreach my $fld (keys %{ $rec }) { |
354 |
$self->{_stats}->{fld}->{ $fld }++; |
355 |
|
356 |
$log->logdie("invalid record fild $fld, not ARRAY") |
357 |
unless (ref($rec->{ $fld }) eq 'ARRAY'); |
358 |
|
359 |
foreach my $row (@{ $rec->{$fld} }) { |
360 |
|
361 |
if (ref($row) eq 'HASH') { |
362 |
|
363 |
foreach my $sf (keys %{ $row }) { |
364 |
next if ($sf eq 'subfields'); |
365 |
$self->{_stats}->{sf}->{ $fld }->{ $sf }->{count}++; |
366 |
$self->{_stats}->{sf}->{ $fld }->{ $sf }->{repeatable}++ |
367 |
if (ref($row->{$sf}) eq 'ARRAY'); |
368 |
} |
369 |
|
370 |
} else { |
371 |
$self->{_stats}->{repeatable}->{ $fld }++; |
372 |
} |
373 |
} |
374 |
} |
375 |
} |
376 |
|
377 |
$self->progress_bar($pos,$to_rec) unless ($self->{no_progress_bar}); |
378 |
|
379 |
} |
380 |
|
381 |
$self->{pos} = -1; |
382 |
$self->{last_pcnt} = 0; |
383 |
|
384 |
# store max mfn and return it. |
385 |
$self->{max_pos} = $to_rec; |
386 |
$log->debug("max_pos: $to_rec"); |
387 |
|
388 |
return $size; |
389 |
} |
390 |
|
391 |
=head2 fetch |
392 |
|
393 |
Fetch next record from database. It will also displays progress bar. |
394 |
|
395 |
my $rec = $isis->fetch; |
396 |
|
397 |
Record from this function should probably go to C<data_structure> for |
398 |
normalisation. |
399 |
|
400 |
=cut |
401 |
|
402 |
sub fetch { |
403 |
my $self = shift; |
404 |
|
405 |
my $log = $self->_get_logger(); |
406 |
|
407 |
$log->logconfess("it seems that you didn't load database!") unless ($self->{pos}); |
408 |
|
409 |
if ($self->{pos} == -1) { |
410 |
$self->{pos} = $self->{offset}; |
411 |
} else { |
412 |
$self->{pos}++; |
413 |
} |
414 |
|
415 |
my $mfn = $self->{pos}; |
416 |
|
417 |
if ($mfn > $self->{max_pos}) { |
418 |
$self->{pos} = $self->{max_pos}; |
419 |
$log->debug("at EOF"); |
420 |
return; |
421 |
} |
422 |
|
423 |
$self->progress_bar($mfn,$self->{max_pos}) unless ($self->{no_progress_bar}); |
424 |
|
425 |
my $rec; |
426 |
|
427 |
if ($self->{low_mem}) { |
428 |
$rec = $self->{db}->get($mfn); |
429 |
} else { |
430 |
$rec = $self->{data}->{$mfn}; |
431 |
} |
432 |
|
433 |
$rec ||= 0E0; |
434 |
} |
435 |
|
436 |
=head2 pos |
437 |
|
438 |
Returns current record number (MFN). |
439 |
|
440 |
print $isis->pos; |
441 |
|
442 |
First record in database has position 1. |
443 |
|
444 |
=cut |
445 |
|
446 |
sub pos { |
447 |
my $self = shift; |
448 |
return $self->{pos}; |
449 |
} |
450 |
|
451 |
|
452 |
=head2 size |
453 |
|
454 |
Returns number of records in database |
455 |
|
456 |
print $isis->size; |
457 |
|
458 |
Result from this function can be used to loop through all records |
459 |
|
460 |
foreach my $mfn ( 1 ... $isis->size ) { ... } |
461 |
|
462 |
because it takes into account C<offset> and C<limit>. |
463 |
|
464 |
=cut |
465 |
|
466 |
sub size { |
467 |
my $self = shift; |
468 |
return $self->{size}; |
469 |
} |
470 |
|
471 |
=head2 seek |
472 |
|
473 |
Seek to specified MFN in file. |
474 |
|
475 |
$isis->seek(42); |
476 |
|
477 |
First record in database has position 1. |
478 |
|
479 |
=cut |
480 |
|
481 |
sub seek { |
482 |
my $self = shift; |
483 |
my $pos = shift || return; |
484 |
|
485 |
my $log = $self->_get_logger(); |
486 |
|
487 |
if ($pos < 1) { |
488 |
$log->warn("seek before first record"); |
489 |
$pos = 1; |
490 |
} elsif ($pos > $self->{max_pos}) { |
491 |
$log->warn("seek beyond last record"); |
492 |
$pos = $self->{max_pos}; |
493 |
} |
494 |
|
495 |
return $self->{pos} = (($pos - 1) || -1); |
496 |
} |
497 |
|
498 |
=head2 stats |
499 |
|
500 |
Dump statistics about field and subfield usage |
501 |
|
502 |
print $input->stats; |
503 |
|
504 |
=cut |
505 |
|
506 |
sub stats { |
507 |
my $self = shift; |
508 |
|
509 |
my $log = $self->_get_logger(); |
510 |
|
511 |
my $s = $self->{_stats}; |
512 |
if (! $s) { |
513 |
$log->warn("called stats, but there is no statistics collected"); |
514 |
return; |
515 |
} |
516 |
|
517 |
my $max_fld = 0; |
518 |
|
519 |
my $out = join("\n", |
520 |
map { |
521 |
my $f = $_ || die "no field"; |
522 |
my $v = $s->{fld}->{$f} || die "no s->{fld}->{$f}"; |
523 |
$max_fld = $v if ($v > $max_fld); |
524 |
|
525 |
my $o = sprintf("%4s %d ~", $f, $v); |
526 |
|
527 |
if (defined($s->{sf}->{$f})) { |
528 |
map { |
529 |
$o .= sprintf(" %s:%d%s", $_, |
530 |
$s->{sf}->{$f}->{$_}->{count}, |
531 |
$s->{sf}->{$f}->{$_}->{repeatable} ? '*' : '', |
532 |
); |
533 |
} sort keys %{ $s->{sf}->{$f} }; |
534 |
} |
535 |
|
536 |
if (my $v_r = $s->{repeatable}->{$f}) { |
537 |
$o .= " ($v_r)" if ($v_r != $v); |
538 |
} |
539 |
|
540 |
$o; |
541 |
} sort { $a cmp $b } keys %{ $s->{fld} } |
542 |
); |
543 |
|
544 |
$log->debug( sub { Dumper($s) } ); |
545 |
|
546 |
return $out; |
547 |
} |
548 |
|
549 |
=head2 modify_record_regexps |
550 |
|
551 |
Generate hash with regexpes to be applied using l<filter>. |
552 |
|
553 |
my $regexpes = $input->modify_record_regexps( |
554 |
900 => { '^a' => { ' : ' => '^b' } }, |
555 |
901 => { '*' => { '^b' => ' ; ' } }, |
556 |
); |
557 |
|
558 |
=cut |
559 |
|
560 |
sub _get_regex { |
561 |
my ($sf,$from,$to) = @_; |
562 |
if ($sf =~ /^\^/) { |
563 |
return |
564 |
's/\Q'. $sf .'\E([^\^]*?)\Q'. $from .'\E([^\^]*?)/'. $sf .'$1'. $to .'$2/'; |
565 |
} else { |
566 |
return |
567 |
's/\Q'. $from .'\E/'. $to .'/g'; |
568 |
} |
569 |
} |
570 |
|
571 |
sub modify_record_regexps { |
572 |
my $self = shift; |
573 |
my $modify_record = {@_}; |
574 |
|
575 |
my $regexpes; |
576 |
|
577 |
my $log = $self->_get_logger(); |
578 |
|
579 |
foreach my $f (keys %$modify_record) { |
580 |
$log->debug("field: $f"); |
581 |
|
582 |
foreach my $sf (keys %{ $modify_record->{$f} }) { |
583 |
$log->debug("subfield: $sf"); |
584 |
|
585 |
foreach my $from (keys %{ $modify_record->{$f}->{$sf} }) { |
586 |
my $to = $modify_record->{$f}->{$sf}->{$from}; |
587 |
#die "no field?" unless defined($to); |
588 |
$log->debug("transform: |$from| -> |$to|"); |
589 |
|
590 |
my $regex = _get_regex($sf,$from,$to); |
591 |
push @{ $regexpes->{$f} }, $regex; |
592 |
$log->debug("regex: $regex"); |
593 |
} |
594 |
} |
595 |
} |
596 |
|
597 |
return $regexpes; |
598 |
} |
599 |
|
600 |
=head2 modify_file_regexps |
601 |
|
602 |
Generate hash with regexpes to be applied using l<filter> from |
603 |
pseudo hash/yaml format for regex mappings. |
604 |
|
605 |
It should be obvious: |
606 |
|
607 |
200 |
608 |
'^a' |
609 |
' : ' => '^e' |
610 |
' = ' => '^d' |
611 |
|
612 |
In field I<200> find C<'^a'> and then C<' : '>, and replace it with C<'^e'>. |
613 |
In field I<200> find C<'^a'> and then C<' = '>, and replace it with C<'^d'>. |
614 |
|
615 |
my $regexpes = $input->modify_file_regexps( 'conf/modify/common.pl' ); |
616 |
|
617 |
On undef path it will just return. |
618 |
|
619 |
=cut |
620 |
|
621 |
sub modify_file_regexps { |
622 |
my $self = shift; |
623 |
|
624 |
my $modify_path = shift || return; |
625 |
|
626 |
my $log = $self->_get_logger(); |
627 |
|
628 |
my $regexpes; |
629 |
|
630 |
CORE::open(my $fh, $modify_path) || $log->die("can't open modify file $modify_path: $!"); |
631 |
|
632 |
my ($f,$sf); |
633 |
|
634 |
while(<$fh>) { |
635 |
chomp; |
636 |
next if (/^#/ || /^\s*$/); |
637 |
|
638 |
if (/^\s*(\d+)\s*$/) { |
639 |
$f = $1; |
640 |
$log->debug("field: $f"); |
641 |
next; |
642 |
} elsif (/^\s*'([^']*)'\s*$/) { |
643 |
$sf = $1; |
644 |
$log->die("can't define subfiled before field in: $_") unless ($f); |
645 |
$log->debug("subfield: $sf"); |
646 |
} elsif (/^\s*'([^']*)'\s*=>\s*'([^']*)'\s*$/) { |
647 |
my ($from,$to) = ($1, $2); |
648 |
|
649 |
$log->debug("transform: |$from| -> |$to|"); |
650 |
|
651 |
my $regex = _get_regex($sf,$from,$to); |
652 |
push @{ $regexpes->{$f} }, $regex; |
653 |
$log->debug("regex: $regex"); |
654 |
} |
655 |
} |
656 |
|
657 |
return $regexpes; |
658 |
} |
659 |
|
660 |
=head1 MEMORY USAGE |
661 |
|
662 |
C<low_mem> options is double-edged sword. If enabled, WebPAC |
663 |
will run on memory constraint machines (which doesn't have enough |
664 |
physical RAM to create memory structure for whole source database). |
665 |
|
666 |
If your machine has 512Mb or more of RAM and database is around 10000 records, |
667 |
memory shouldn't be an issue. If you don't have enough physical RAM, you |
668 |
might consider using virtual memory (if your operating system is handling it |
669 |
well, like on FreeBSD or Linux) instead of dropping to L<DBM::Deep> to handle |
670 |
parsed structure of ISIS database (this is what C<low_mem> option does). |
671 |
|
672 |
Hitting swap at end of reading source database is probably o.k. However, |
673 |
hitting swap before 90% will dramatically decrease performance and you will |
674 |
be better off with C<low_mem> and using rest of availble memory for |
675 |
operating system disk cache (Linux is particuallary good about this). |
676 |
However, every access to database record will require disk access, so |
677 |
generation phase will be slower 10-100 times. |
678 |
|
679 |
Parsed structures are essential - you just have option to trade RAM memory |
680 |
(which is fast) for disk space (which is slow). Be sure to have planty of |
681 |
disk space if you are using C<low_mem> and thus L<DBM::Deep>. |
682 |
|
683 |
However, when WebPAC is running on desktop machines (or laptops :-), it's |
684 |
highly undesireable for system to start swapping. Using C<low_mem> option can |
685 |
reduce WecPAC memory usage to around 64Mb for same database with lookup |
686 |
fields and sorted indexes which stay in RAM. Performance will suffer, but |
687 |
memory usage will really be minimal. It might be also more confortable to |
688 |
run WebPAC reniced on those machines. |
689 |
|
690 |
|
691 |
=head1 AUTHOR |
692 |
|
693 |
Dobrica Pavlinusic, C<< <dpavlin@rot13.org> >> |
694 |
|
695 |
=head1 COPYRIGHT & LICENSE |
696 |
|
697 |
Copyright 2005-2006 Dobrica Pavlinusic, All Rights Reserved. |
698 |
|
699 |
This program is free software; you can redistribute it and/or modify it |
700 |
under the same terms as Perl itself. |
701 |
|
702 |
=cut |
703 |
|
704 |
1; # End of WebPAC::Input |