/[webpac2]/trunk/lib/WebPAC/Input.pm
This is repository of my old source code which isn't updated any more. Go to git.rot13.org for current projects!
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revision 285 by dpavlin, Sun Dec 18 21:06:39 2005 UTC revision 289 by dpavlin, Sun Dec 18 22:16:44 2005 UTC
# Line 11  use Text::Iconv; Line 11  use Text::Iconv;
11    
12  =head1 NAME  =head1 NAME
13    
14  WebPAC::Input - core module for input file format  WebPAC::Input - read different file formats into WebPAC
15    
16  =head1 VERSION  =head1 VERSION
17    
18  Version 0.02  Version 0.03
19    
20  =cut  =cut
21    
22  our $VERSION = '0.02';  our $VERSION = '0.03';
23    
24  =head1 SYNOPSIS  =head1 SYNOPSIS
25    
26  This module is used as base class for all database specific modules  This module implements input as database which have fixed and known
27  (basically, files which have one handle, fixed size while indexing and some  I<size> while indexing and single unique numeric identifier for database
28  kind of numeric idefinirier which goes from 1 to filesize).  position ranging from 1 to I<size>.
29    
30    Simply, something that is indexed by unmber from 1 .. I<size>.
31    
32    Examples of such databases are CDS/ISIS files, MARC files, lines in
33    text file, and so on.
34    
35    Specific file formats are implemented using low-level interface modules,
36    located in C<WebPAC::Input::*> namespace which export C<open_db>,
37    C<fetch_rec> and optional C<init> functions.
38    
39  Perhaps a little code snippet.  Perhaps a little code snippet.
40    
41      use WebPAC::Input;      use WebPAC::Input;
42    
43      my $db = WebPAC::Input->new(      my $db = WebPAC::Input->new(
44          format => 'NULL',          module => 'WebPAC::Input::ISIS',
45          config => $config,                  config => $config,
46          lookup => $lookup_obj,                  lookup => $lookup_obj,
47          low_mem => 1,                  low_mem => 1,
48      );      );
49    
50      $db->open('/path/to/database');      $db->open('/path/to/database');
51      print "database size: ",$db->size,"\n";      print "database size: ",$db->size,"\n";
52      while (my $row = $db->fetch) {      while (my $rec = $db->fetch) {
         ...  
53      }      }
54    
55    
56    
57  =head1 FUNCTIONS  =head1 FUNCTIONS
58    
59  =head2 new  =head2 new
# Line 51  Perhaps a little code snippet. Line 61  Perhaps a little code snippet.
61  Create new input database object.  Create new input database object.
62    
63    my $db = new WebPAC::Input(    my $db = new WebPAC::Input(
64          format => 'NULL'          module => 'WebPAC::Input::MARC',
65          code_page => 'ISO-8859-2',          code_page => 'ISO-8859-2',
66          low_mem => 1,          low_mem => 1,
67    );    );
68    
69    C<module> is low-level file format module. See L<WebPAC::Input::Isis> and
70    L<WebPAC::Input::MARC>.
71    
72  Optional parametar C<code_page> specify application code page (which will be  Optional parametar C<code_page> specify application code page (which will be
73  used internally). This should probably be your terminal encoding, and by  used internally). This should probably be your terminal encoding, and by
74  default, it C<ISO-8859-2>.  default, it C<ISO-8859-2>.
# Line 74  sub new { Line 87  sub new {
87    
88          my $log = $self->_get_logger;          my $log = $self->_get_logger;
89    
90            $log->logconfess("specify low-level file format module") unless ($self->{module});
91            my $module = $self->{module};
92            $module =~ s#::#/#g;
93            $module .= '.pm';
94            $log->debug("require low-level module $self->{module} from $module");
95    
96            require $module;
97            #eval $self->{module} .'->import';
98    
99          # check if required subclasses are implemented          # check if required subclasses are implemented
100          foreach my $subclass (qw/open_db fetch_rec/) {          foreach my $subclass (qw/open_db fetch_rec init/) {
101                  $log->logdie("missing implementation of $subclass") unless ($self->SUPER::can($subclass));                  my $n = $self->{module} . '::' . $subclass;
102                    if (! defined &{ $n }) {
103                            $log->logwarn("missing implementation of $subclass");
104                    } else {
105                            $self->{$subclass} = \&{ $n };
106                    }
107          }          }
108    
109          if ($self->can('init')) {          if ($self->{init}) {
110                  $log->debug("calling init");                  $log->debug("calling init");
111                  $self->init(@_);                  $self->{init}->($self, @_);
112          }          }
113    
114          $self->{'code_page'} ||= 'ISO-8859-2';          $self->{'code_page'} ||= 'ISO-8859-2';
# Line 119  sub new { Line 146  sub new {
146    
147  This function will read whole database in memory and produce lookups.  This function will read whole database in memory and produce lookups.
148    
149   $isis->open(   $input->open(
150          path => '/path/to/database/file',          path => '/path/to/database/file',
151          code_page => '852',          code_page => '852',
152          limit_mfn => 500,          limit => 500,
153          start_mfn => 6000,          offset => 6000,
154          lookup => $lookup_obj,          lookup => $lookup_obj,
155   );   );
156    
157  By default, C<code_page> is assumed to be C<852>.  By default, C<code_page> is assumed to be C<852>.
158    
159  If optional parametar C<start_mfn> is set, this will be first MFN to read  C<offset> is optional parametar to position at some offset before reading from database.
 from database (so you can skip beginning of your database if you need to).  
160    
161  If optional parametar C<limit_mfn> is set, it will read just 500 records  C<limit> is optional parametar to read just C<limit> records from database
 from database in example above.  
162    
163  Returns size of database, regardless of C<start_mfn> and C<limit_mfn>  Returns size of database, regardless of C<offset> and C<limit>
164  parametars, see also C<$isis->size>.  parametars, see also C<size>.
165    
166  =cut  =cut
167    
# Line 151  sub open { Line 176  sub open {
176    
177          # store data in object          # store data in object
178          $self->{'code_page'} = $code_page;          $self->{'code_page'} = $code_page;
179          foreach my $v (qw/path start_mfn limit_mfn/) {          foreach my $v (qw/path offset limit/) {
180                  $self->{$v} = $arg->{$v} if ($arg->{$v});                  $self->{$v} = $arg->{$v} if ($arg->{$v});
181          }          }
182    
183          # create Text::Iconv object          # create Text::Iconv object
184          $self->{iconv} = Text::Iconv->new($code_page,$self->{'code_page'});          $self->{iconv} = Text::Iconv->new($code_page,$self->{'code_page'});
185    
186          my ($db, $size) = $self->open_db(          my ($db, $size) = $self->{open_db}->( $self,
187                  path => $arg->{path},                  path => $arg->{path},
188          );          );
189    
# Line 172  sub open { Line 197  sub open {
197                  return;                  return;
198          }          }
199    
200          my $startmfn = 1;          my $offset = 1;
201          my $maxmfn = $size;          my $limit = $size;
202    
203          if (my $s = $self->{start_mfn}) {          if (my $s = $self->{offset}) {
204                  $log->info("skipping to MFN $s");                  $log->info("skipping to MFN $s");
205                  $startmfn = $s;                  $offset = $s;
206          } else {          } else {
207                  $self->{start_mfn} = $startmfn;                  $self->{offset} = $offset;
208          }          }
209    
210          if ($self->{limit_mfn}) {          if ($self->{limit}) {
211                  $log->info("limiting to ",$self->{limit_mfn}," records");                  $log->info("limiting to ",$self->{limit}," records");
212                  $maxmfn = $startmfn + $self->{limit_mfn} - 1;                  $limit = $offset + $self->{limit} - 1;
213                  $maxmfn = $size if ($maxmfn > $size);                  $limit = $size if ($limit > $size);
214          }          }
215    
216          # store size for later          # store size for later
217          $self->{size} = ($maxmfn - $startmfn) ? ($maxmfn - $startmfn + 1) : 0;          $self->{size} = ($limit - $offset) ? ($limit - $offset + 1) : 0;
218    
219          $log->info("processing $self->{size} records in $code_page, convert to $self->{code_page}");          $log->info("processing $self->{size} records in $code_page, convert to $self->{code_page}");
220    
221          # read database          # read database
222          for (my $mfn = $startmfn; $mfn <= $maxmfn; $mfn++) {          for (my $pos = $offset; $pos <= $limit; $pos++) {
223    
224                  $log->debug("mfn: $mfn\n");                  $log->debug("position: $pos\n");
225    
226                  my $rec = $self->fetch_rec( $db, $mfn );                  my $rec = $self->{fetch_rec}->($self, $db, $pos );
227    
228                  if (! $rec) {                  if (! $rec) {
229                          $log->warn("record $mfn empty? skipping...");                          $log->warn("record $pos empty? skipping...");
230                          next;                          next;
231                  }                  }
232    
233                  # store                  # store
234                  if ($self->{'low_mem'}) {                  if ($self->{low_mem}) {
235                          $self->{'db'}->put($mfn, $rec);                          $self->{db}->put($pos, $rec);
236                  } else {                  } else {
237                          $self->{'data'}->{$mfn} = $rec;                          $self->{data}->{$pos} = $rec;
238                  }                  }
239    
240                  # create lookup                  # create lookup
241                  $self->{'lookup'}->add( $rec ) if ($rec && $self->{'lookup'});                  $self->{'lookup'}->add( $rec ) if ($rec && $self->{'lookup'});
242    
243                  $self->progress_bar($mfn,$maxmfn);                  $self->progress_bar($pos,$limit);
244    
245          }          }
246    
247          $self->{'current_mfn'} = -1;          $self->{pos} = -1;
248          $self->{'last_pcnt'} = 0;          $self->{last_pcnt} = 0;
   
         $log->debug("max mfn: $maxmfn");  
249    
250          # store max mfn and return it.          # store max mfn and return it.
251          $self->{'max_mfn'} = $maxmfn;          $self->{max_pos} = $limit;
252            $log->debug("max_pos: $limit");
253    
254          return $size;          return $size;
255  }  }
# Line 246  sub fetch { Line 270  sub fetch {
270    
271          my $log = $self->_get_logger();          my $log = $self->_get_logger();
272    
273          $log->logconfess("it seems that you didn't load database!") unless ($self->{'current_mfn'});          $log->logconfess("it seems that you didn't load database!") unless ($self->{pos});
274    
275          if ($self->{'current_mfn'} == -1) {          if ($self->{pos} == -1) {
276                  $self->{'current_mfn'} = $self->{'start_mfn'};                  $self->{pos} = $self->{offset};
277          } else {          } else {
278                  $self->{'current_mfn'}++;                  $self->{pos}++;
279          }          }
280    
281          my $mfn = $self->{'current_mfn'};          my $mfn = $self->{pos};
282    
283          if ($mfn > $self->{'max_mfn'}) {          if ($mfn > $self->{max_pos}) {
284                  $self->{'current_mfn'} = $self->{'max_mfn'};                  $self->{pos} = $self->{max_pos};
285                  $log->debug("at EOF");                  $log->debug("at EOF");
286                  return;                  return;
287          }          }
288    
289          $self->progress_bar($mfn,$self->{'max_mfn'});          $self->progress_bar($mfn,$self->{max_pos});
290    
291          my $rec;          my $rec;
292    
293          if ($self->{'low_mem'}) {          if ($self->{low_mem}) {
294                  $rec = $self->{'db'}->get($mfn);                  $rec = $self->{db}->get($mfn);
295          } else {          } else {
296                  $rec = $self->{'data'}->{$mfn};                  $rec = $self->{data}->{$mfn};
297          }          }
298    
299          $rec ||= 0E0;          $rec ||= 0E0;
# Line 287  First record in database has position 1. Line 311  First record in database has position 1.
311    
312  sub pos {  sub pos {
313          my $self = shift;          my $self = shift;
314          return $self->{'current_mfn'};          return $self->{pos};
315  }  }
316    
317    
# Line 301  Result from this function can be used to Line 325  Result from this function can be used to
325    
326   foreach my $mfn ( 1 ... $isis->size ) { ... }   foreach my $mfn ( 1 ... $isis->size ) { ... }
327    
328  because it takes into account C<start_mfn> and C<limit_mfn>.  because it takes into account C<offset> and C<limit>.
329    
330  =cut  =cut
331    
332  sub size {  sub size {
333          my $self = shift;          my $self = shift;
334          return $self->{'size'};          return $self->{size};
335  }  }
336    
337  =head2 seek  =head2 seek
# Line 329  sub seek { Line 353  sub seek {
353          if ($pos < 1) {          if ($pos < 1) {
354                  $log->warn("seek before first record");                  $log->warn("seek before first record");
355                  $pos = 1;                  $pos = 1;
356          } elsif ($pos > $self->{'max_mfn'}) {          } elsif ($pos > $self->{max_pos}) {
357                  $log->warn("seek beyond last record");                  $log->warn("seek beyond last record");
358                  $pos = $self->{'max_mfn'};                  $pos = $self->{max_pos};
359          }          }
360    
361          return $self->{'current_mfn'} = (($pos - 1) || -1);          return $self->{pos} = (($pos - 1) || -1);
362  }  }
363    
364    
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