| 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 Text::Iconv; |
| 11 |
use Data::Dumper; |
| 12 |
|
| 13 |
=head1 NAME |
| 14 |
|
| 15 |
WebPAC::Input - read different file formats into WebPAC |
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|
| 17 |
=head1 VERSION |
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|
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Version 0.05 |
| 20 |
|
| 21 |
=cut |
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|
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our $VERSION = '0.05'; |
| 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>. |
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|
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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( |
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module => 'WebPAC::Input::ISIS', |
| 46 |
config => $config, |
| 47 |
lookup => $lookup_obj, |
| 48 |
low_mem => 1, |
| 49 |
); |
| 50 |
|
| 51 |
$db->open('/path/to/database'); |
| 52 |
print "database size: ",$db->size,"\n"; |
| 53 |
while (my $rec = $db->fetch) { |
| 54 |
# do something with $rec |
| 55 |
} |
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|
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|
| 58 |
|
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=head1 FUNCTIONS |
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|
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=head2 new |
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|
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Create new input database object. |
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|
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my $db = new WebPAC::Input( |
| 66 |
module => 'WebPAC::Input::MARC', |
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code_page => 'ISO-8859-2', |
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low_mem => 1, |
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recode => 'char pairs', |
| 70 |
no_progress_bar => 1, |
| 71 |
); |
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|
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C<module> is low-level file format module. See L<WebPAC::Input::Isis> and |
| 74 |
L<WebPAC::Input::MARC>. |
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|
| 76 |
Optional parametar C<code_page> specify application code page (which will be |
| 77 |
used internally). This should probably be your terminal encoding, and by |
| 78 |
default, it C<ISO-8859-2>. |
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|
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Default is not to use C<low_mem> options (see L<MEMORY USAGE> below). |
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|
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C<recode> is optional string constisting of character or words pairs that |
| 83 |
should be replaced in input stream. |
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|
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C<no_progress_bar> disables progress bar output on C<STDOUT> |
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|
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This function will also call low-level C<init> if it exists with same |
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parametars. |
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|
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=cut |
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|
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sub new { |
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my $class = shift; |
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my $self = {@_}; |
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bless($self, $class); |
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|
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my $log = $self->_get_logger; |
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|
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$log->logconfess("specify low-level file format module") unless ($self->{module}); |
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my $module = $self->{module}; |
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$module =~ s#::#/#g; |
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$module .= '.pm'; |
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$log->debug("require low-level module $self->{module} from $module"); |
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|
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require $module; |
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#eval $self->{module} .'->import'; |
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|
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# check if required subclasses are implemented |
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foreach my $subclass (qw/open_db fetch_rec init/) { |
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my $n = $self->{module} . '::' . $subclass; |
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if (! defined &{ $n }) { |
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my $missing = "missing $subclass in $self->{module}"; |
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$self->{$subclass} = sub { $log->logwarn($missing) }; |
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} else { |
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$self->{$subclass} = \&{ $n }; |
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} |
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} |
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|
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if ($self->{init}) { |
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$log->debug("calling init"); |
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$self->{init}->($self, @_); |
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} |
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|
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$self->{'code_page'} ||= 'ISO-8859-2'; |
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|
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# running with low_mem flag? well, use DBM::Deep then. |
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if ($self->{'low_mem'}) { |
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$log->info("running with low_mem which impacts performance (<32 Mb memory usage)"); |
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|
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my $db_file = "data.db"; |
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|
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if (-e $db_file) { |
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unlink $db_file or $log->logdie("can't remove '$db_file' from last run"); |
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$log->debug("removed '$db_file' from last run"); |
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} |
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|
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require DBM::Deep; |
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|
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my $db = new DBM::Deep $db_file; |
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|
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$log->logdie("DBM::Deep error: $!") unless ($db); |
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|
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if ($db->error()) { |
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$log->logdie("can't open '$db_file' under low_mem: ",$db->error()); |
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} else { |
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$log->debug("using file '$db_file' for DBM::Deep"); |
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} |
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|
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$self->{'db'} = $db; |
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} |
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|
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$self ? return $self : return undef; |
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} |
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|
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=head2 open |
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|
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This function will read whole database in memory and produce lookups. |
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|
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$input->open( |
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path => '/path/to/database/file', |
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code_page => '852', |
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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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); |
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|
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By default, C<code_page> is assumed to be C<852>. |
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|
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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 |
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|
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C<stats> create optional report about usage of fields and subfields |
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|
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Returns size of database, regardless of C<offset> and C<limit> |
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parametars, see also C<size>. |
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|
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=cut |
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|
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sub open { |
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my $self = shift; |
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my $arg = {@_}; |
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|
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my $log = $self->_get_logger(); |
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|
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$log->logcroak("need path") if (! $arg->{'path'}); |
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my $code_page = $arg->{'code_page'} || '852'; |
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|
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# store data in object |
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$self->{'input_code_page'} = $code_page; |
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foreach my $v (qw/path offset limit/) { |
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$self->{$v} = $arg->{$v} if ($arg->{$v}); |
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} |
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|
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# create Text::Iconv object |
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$self->{iconv} = Text::Iconv->new($code_page,$self->{'code_page'}); |
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|
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my $filter_ref; |
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|
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if ($self->{recode}) { |
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my @r = split(/\s/, $self->{recode}); |
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if ($#r % 2 != 1) { |
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$log->logwarn("recode needs even number of elements (some number of valid pairs)"); |
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} else { |
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my $recode; |
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while (@r) { |
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my $from = shift @r; |
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my $to = shift @r; |
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$recode->{$from} = $to; |
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} |
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|
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my $regex = join '|' => keys %{ $recode }; |
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|
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$log->debug("using recode regex: $regex"); |
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|
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$filter_ref = sub { |
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my $t = shift; |
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$t =~ s/($regex)/$recode->{$1}/g; |
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return $t; |
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}; |
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|
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} |
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|
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} |
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|
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my ($db, $size) = $self->{open_db}->( $self, |
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path => $arg->{path}, |
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filter => $filter_ref, |
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); |
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|
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unless (defined($db)) { |
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$log->logwarn("can't open database $arg->{path}, skipping..."); |
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return; |
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} |
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|
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unless ($size) { |
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$log->logwarn("no records in database $arg->{path}, skipping..."); |
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return; |
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} |
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|
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my $from_rec = 1; |
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my $to_rec = $size; |
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|
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if (my $s = $self->{offset}) { |
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$log->debug("skipping to MFN $s"); |
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$from_rec = $s; |
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} else { |
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$self->{offset} = $from_rec; |
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} |
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|
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if ($self->{limit}) { |
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$log->debug("limiting to ",$self->{limit}," records"); |
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$to_rec = $from_rec + $self->{limit} - 1; |
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$to_rec = $size if ($to_rec > $size); |
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} |
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|
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# store size for later |
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$self->{size} = ($to_rec - $from_rec) ? ($to_rec - $from_rec + 1) : 0; |
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|
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$log->info("processing $self->{size}/$size records [$from_rec-$to_rec] convert $code_page -> $self->{code_page}", $self->{stats} ? ' [stats]' : ''); |
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|
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# read database |
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for (my $pos = $from_rec; $pos <= $to_rec; $pos++) { |
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|
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$log->debug("position: $pos\n"); |
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|
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my $rec = $self->{fetch_rec}->($self, $db, $pos ); |
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|
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$log->debug(sub { Dumper($rec) }); |
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|
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if (! $rec) { |
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$log->warn("record $pos empty? skipping..."); |
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next; |
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} |
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|
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# store |
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if ($self->{low_mem}) { |
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$self->{db}->put($pos, $rec); |
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} else { |
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$self->{data}->{$pos} = $rec; |
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} |
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|
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# create lookup |
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$self->{'lookup'}->add( $rec ) if ($rec && $self->{'lookup'}); |
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|
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# update counters for statistics |
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if ($self->{stats}) { |
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map { |
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my $fld = $_; |
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$self->{_stats}->{fld}->{ $fld }++; |
| 292 |
if (ref($rec->{ $fld }) eq 'ARRAY') { |
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map { |
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if (ref($_) eq 'HASH') { |
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map { |
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$self->{_stats}->{sf}->{ $fld }->{ $_ }++; |
| 297 |
} keys %{ $_ }; |
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} else { |
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$self->{_stats}->{repeatable}->{ $fld }++; |
| 300 |
} |
| 301 |
} @{ $rec->{$fld} }; |
| 302 |
} |
| 303 |
} keys %{ $rec }; |
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} |
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|
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$self->progress_bar($pos,$to_rec) unless ($self->{no_progress_bar}); |
| 307 |
|
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} |
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|
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$self->{pos} = -1; |
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$self->{last_pcnt} = 0; |
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|
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# store max mfn and return it. |
| 314 |
$self->{max_pos} = $to_rec; |
| 315 |
$log->debug("max_pos: $to_rec"); |
| 316 |
|
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return $size; |
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} |
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|
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=head2 fetch |
| 321 |
|
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Fetch next record from database. It will also displays progress bar. |
| 323 |
|
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my $rec = $isis->fetch; |
| 325 |
|
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Record from this function should probably go to C<data_structure> for |
| 327 |
normalisation. |
| 328 |
|
| 329 |
=cut |
| 330 |
|
| 331 |
sub fetch { |
| 332 |
my $self = shift; |
| 333 |
|
| 334 |
my $log = $self->_get_logger(); |
| 335 |
|
| 336 |
$log->logconfess("it seems that you didn't load database!") unless ($self->{pos}); |
| 337 |
|
| 338 |
if ($self->{pos} == -1) { |
| 339 |
$self->{pos} = $self->{offset}; |
| 340 |
} else { |
| 341 |
$self->{pos}++; |
| 342 |
} |
| 343 |
|
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my $mfn = $self->{pos}; |
| 345 |
|
| 346 |
if ($mfn > $self->{max_pos}) { |
| 347 |
$self->{pos} = $self->{max_pos}; |
| 348 |
$log->debug("at EOF"); |
| 349 |
return; |
| 350 |
} |
| 351 |
|
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$self->progress_bar($mfn,$self->{max_pos}) unless ($self->{no_progress_bar}); |
| 353 |
|
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my $rec; |
| 355 |
|
| 356 |
if ($self->{low_mem}) { |
| 357 |
$rec = $self->{db}->get($mfn); |
| 358 |
} else { |
| 359 |
$rec = $self->{data}->{$mfn}; |
| 360 |
} |
| 361 |
|
| 362 |
$rec ||= 0E0; |
| 363 |
} |
| 364 |
|
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=head2 pos |
| 366 |
|
| 367 |
Returns current record number (MFN). |
| 368 |
|
| 369 |
print $isis->pos; |
| 370 |
|
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First record in database has position 1. |
| 372 |
|
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=cut |
| 374 |
|
| 375 |
sub pos { |
| 376 |
my $self = shift; |
| 377 |
return $self->{pos}; |
| 378 |
} |
| 379 |
|
| 380 |
|
| 381 |
=head2 size |
| 382 |
|
| 383 |
Returns number of records in database |
| 384 |
|
| 385 |
print $isis->size; |
| 386 |
|
| 387 |
Result from this function can be used to loop through all records |
| 388 |
|
| 389 |
foreach my $mfn ( 1 ... $isis->size ) { ... } |
| 390 |
|
| 391 |
because it takes into account C<offset> and C<limit>. |
| 392 |
|
| 393 |
=cut |
| 394 |
|
| 395 |
sub size { |
| 396 |
my $self = shift; |
| 397 |
return $self->{size}; |
| 398 |
} |
| 399 |
|
| 400 |
=head2 seek |
| 401 |
|
| 402 |
Seek to specified MFN in file. |
| 403 |
|
| 404 |
$isis->seek(42); |
| 405 |
|
| 406 |
First record in database has position 1. |
| 407 |
|
| 408 |
=cut |
| 409 |
|
| 410 |
sub seek { |
| 411 |
my $self = shift; |
| 412 |
my $pos = shift || return; |
| 413 |
|
| 414 |
my $log = $self->_get_logger(); |
| 415 |
|
| 416 |
if ($pos < 1) { |
| 417 |
$log->warn("seek before first record"); |
| 418 |
$pos = 1; |
| 419 |
} elsif ($pos > $self->{max_pos}) { |
| 420 |
$log->warn("seek beyond last record"); |
| 421 |
$pos = $self->{max_pos}; |
| 422 |
} |
| 423 |
|
| 424 |
return $self->{pos} = (($pos - 1) || -1); |
| 425 |
} |
| 426 |
|
| 427 |
=head2 stats |
| 428 |
|
| 429 |
Dump statistics about field and subfield usage |
| 430 |
|
| 431 |
print $input->stats; |
| 432 |
|
| 433 |
=cut |
| 434 |
|
| 435 |
sub stats { |
| 436 |
my $self = shift; |
| 437 |
|
| 438 |
my $log = $self->_get_logger(); |
| 439 |
|
| 440 |
my $s = $self->{_stats}; |
| 441 |
if (! $s) { |
| 442 |
$log->warn("called stats, but there is no statistics collected"); |
| 443 |
return; |
| 444 |
} |
| 445 |
|
| 446 |
my $max_fld = 0; |
| 447 |
|
| 448 |
my $out = join("\n", |
| 449 |
map { |
| 450 |
my $f = $_ || die "no field"; |
| 451 |
my $v = $s->{fld}->{$f} || die "no s->{fld}->{$f}"; |
| 452 |
$max_fld = $v if ($v > $max_fld); |
| 453 |
|
| 454 |
my $o = sprintf("%4d %d ~", $f, $v); |
| 455 |
|
| 456 |
if (defined($s->{sf}->{$f})) { |
| 457 |
map { |
| 458 |
$o .= sprintf(" %s:%d", $_, $s->{sf}->{$f}->{$_}); |
| 459 |
} sort keys %{ $s->{sf}->{$f} }; |
| 460 |
} |
| 461 |
|
| 462 |
if (my $v_r = $s->{repeatable}->{$f}) { |
| 463 |
$o .= " ($v_r)" if ($v_r != $v); |
| 464 |
} |
| 465 |
|
| 466 |
$o; |
| 467 |
} sort { $a <=> $b } keys %{ $s->{fld} } |
| 468 |
); |
| 469 |
|
| 470 |
$log->debug( sub { Dumper($s) } ); |
| 471 |
|
| 472 |
return $out; |
| 473 |
} |
| 474 |
|
| 475 |
=head1 MEMORY USAGE |
| 476 |
|
| 477 |
C<low_mem> options is double-edged sword. If enabled, WebPAC |
| 478 |
will run on memory constraint machines (which doesn't have enough |
| 479 |
physical RAM to create memory structure for whole source database). |
| 480 |
|
| 481 |
If your machine has 512Mb or more of RAM and database is around 10000 records, |
| 482 |
memory shouldn't be an issue. If you don't have enough physical RAM, you |
| 483 |
might consider using virtual memory (if your operating system is handling it |
| 484 |
well, like on FreeBSD or Linux) instead of dropping to L<DBM::Deep> to handle |
| 485 |
parsed structure of ISIS database (this is what C<low_mem> option does). |
| 486 |
|
| 487 |
Hitting swap at end of reading source database is probably o.k. However, |
| 488 |
hitting swap before 90% will dramatically decrease performance and you will |
| 489 |
be better off with C<low_mem> and using rest of availble memory for |
| 490 |
operating system disk cache (Linux is particuallary good about this). |
| 491 |
However, every access to database record will require disk access, so |
| 492 |
generation phase will be slower 10-100 times. |
| 493 |
|
| 494 |
Parsed structures are essential - you just have option to trade RAM memory |
| 495 |
(which is fast) for disk space (which is slow). Be sure to have planty of |
| 496 |
disk space if you are using C<low_mem> and thus L<DBM::Deep>. |
| 497 |
|
| 498 |
However, when WebPAC is running on desktop machines (or laptops :-), it's |
| 499 |
highly undesireable for system to start swapping. Using C<low_mem> option can |
| 500 |
reduce WecPAC memory usage to around 64Mb for same database with lookup |
| 501 |
fields and sorted indexes which stay in RAM. Performance will suffer, but |
| 502 |
memory usage will really be minimal. It might be also more confortable to |
| 503 |
run WebPAC reniced on those machines. |
| 504 |
|
| 505 |
|
| 506 |
=head1 AUTHOR |
| 507 |
|
| 508 |
Dobrica Pavlinusic, C<< <dpavlin@rot13.org> >> |
| 509 |
|
| 510 |
=head1 COPYRIGHT & LICENSE |
| 511 |
|
| 512 |
Copyright 2005 Dobrica Pavlinusic, All Rights Reserved. |
| 513 |
|
| 514 |
This program is free software; you can redistribute it and/or modify it |
| 515 |
under the same terms as Perl itself. |
| 516 |
|
| 517 |
=cut |
| 518 |
|
| 519 |
1; # End of WebPAC::Input |
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