This file is indexed.

/usr/share/perl5/POE/Queue/Array.pm is in libpoe-perl 2:1.3540-1.

This file is owned by root:root, with mode 0o644.

The actual contents of the file can be viewed below.

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
# Copyrights and documentation are at the end.

package POE::Queue::Array;

use strict;

use vars qw($VERSION @ISA);
$VERSION = '1.354'; # NOTE - Should be #.### (three decimal places)
@ISA = qw(POE::Queue);

use Errno qw(ESRCH EPERM);
use Carp qw(confess);

sub DEBUG () { 0 }

### Helpful offsets.

sub ITEM_PRIORITY () { 0 }
sub ITEM_ID       () { 1 }
sub ITEM_PAYLOAD  () { 2 }

sub import {
  my $package = caller();
  no strict 'refs';
  *{ $package . '::ITEM_PRIORITY' } = \&ITEM_PRIORITY;
  *{ $package . '::ITEM_ID'       } = \&ITEM_ID;
  *{ $package . '::ITEM_PAYLOAD'  } = \&ITEM_PAYLOAD;
}

# Item IDs are unique across all queues.

my $queue_seq = 0;
my %item_priority;

### A very simple constructor.

sub new {
  bless [], shift();
}

### Add an item to the queue.  Returns the new item's ID.

sub enqueue {
  my ($self, $priority, $payload) = @_;

  # Get the next item ID.  This clever loop will hang indefinitely if
  # you ever run out of integers to store things under.  Map the ID to
  # its due time for search-by-ID functions.

  my $item_id;
  1 while exists $item_priority{$item_id = ++$queue_seq};
  $item_priority{$item_id} = $priority;

  my $item_to_enqueue = [
    $priority, # ITEM_PRIORITY
    $item_id,  # ITEM_ID
    $payload,  # ITEM_PAYLOAD
  ];

  # Special case: No items in the queue.  The queue IS the item.
  unless (@$self) {
    $self->[0] = $item_to_enqueue;
    DEBUG and warn $self->_dump_splice(0);
    return $item_id;
  }

  # Special case: The new item belongs at the end of the queue.
  if ($priority >= $self->[-1]->[ITEM_PRIORITY]) {
    push @$self, $item_to_enqueue;
    DEBUG and warn $self->_dump_splice(@$self-1);
    return $item_id;
  }

  # Special case: The new item belongs at the head of the queue.
  if ($priority < $self->[0]->[ITEM_PRIORITY]) {
    unshift @$self, $item_to_enqueue;
    DEBUG and warn $self->_dump_splice(0);
    return $item_id;
  }

  # Special case: There are only two items in the queue.  This item
  # naturally belongs between them.
  if (@$self == 2) {
    splice @$self, 1, 0, $item_to_enqueue;
    DEBUG and warn $self->_dump_splice(1);
    return $item_id;
  }

  # And finally we have a nontrivial queue.  Insert the item using a
  # binary seek.

  $self->_insert_item(0, $#$self, $priority, $item_to_enqueue);
  return $item_id;
}

### Dequeue the next thing from the queue.  Returns an empty list if
### the queue is empty.  There are different flavors of this
### operation.

sub dequeue_next {
  my $self = shift;

  return unless @$self;
  my ($priority, $id, $stuff) = @{shift @$self};
  delete $item_priority{$id};
  return ($priority, $id, $stuff);
}

### Return the next item's priority, undef if the queue is empty.
# This is POE's most-called method.  We could greatly benefit from
# finding ways to reduce the number of calls.

sub get_next_priority {
  # This is Ton Hospel's optimization.
  # He measured a 4% improvement by avoiding $self.
  return (shift->[0] || return undef)->[ITEM_PRIORITY];
}

### Return the number of items currently in the queue.

sub get_item_count {
  return scalar @{$_[0]};
}

### Internal method to insert an item using a binary seek and splice.
### We accept the bounds as parameters because the alarm adjustment
### functions may also use it.

sub _insert_item {
  my ($self, $lower, $upper, $priority, $item) = @_;

  while (1) {
    my $midpoint = ($upper + $lower) >> 1;

    # Upper and lower bounds crossed.  Insert at the lower point.
    if ($upper < $lower) {
      splice @$self, $lower, 0, $item;
      DEBUG and warn $self->_dump_splice($lower);
      return;
    }

    # We're looking for a priority lower than the one at the midpoint.
    # Set the new upper point to just before the midpoint.
    if ($priority < $self->[$midpoint]->[ITEM_PRIORITY]) {
      $upper = $midpoint - 1;
      next;
    }

    # We're looking for a priority greater or equal to the one at the
    # midpoint.  The new lower bound is just after the midpoint.
    $lower = $midpoint + 1;
  }
}

### Internal method to find a queue item by its priority and ID.  We
### assume the priority and ID have been verified already, so the item
### must exist.  Returns the index of the item that matches the
### priority/ID pair.

sub _find_item {
  my ($self, $id, $priority) = @_;

  # Use a binary seek.

  my $upper = $#$self; # Last index of @$self.
  my $lower = 0;
  while (1) {
    my $midpoint = ($upper + $lower) >> 1;

    # Upper and lower bounds crossed.  The lower point is aimed at an
    # element with a priority higher than our target.
    last if $upper < $lower;

    # We're looking for a priority lower than the one at the midpoint.
    # Set the new upper point to just before the midpoint.
    if ($priority < $self->[$midpoint]->[ITEM_PRIORITY]) {
      $upper = $midpoint - 1;
      next;
    }

    # We're looking for a priority greater or equal to the one at the
    # midpoint.  The new lower bound is just after the midpoint.
    $lower = $midpoint + 1;
  }

  # The lower index is pointing to an element with a priority higher
  # than our target.  Scan backwards until we find the item with the
  # target ID.
  while ($lower-- >= 0) {
    return $lower if $self->[$lower]->[ITEM_ID] == $id;
  }

  die "should never get here... maybe the queue is out of order";

}

### Remove an item by its ID.  Takes a coderef filter, too, for
### examining the payload to be sure it really wants to leave.  Sets
### $! and returns undef on failure.

sub remove_item {
  my ($self, $id, $filter) = @_;

  my $priority = $item_priority{$id};
  unless (defined $priority) {
    $! = ESRCH;
    return;
  }

  # Find that darn item.
  my $item_index = $self->_find_item($id, $priority);

  # Test the item against the filter.
  unless ($filter->($self->[$item_index]->[ITEM_PAYLOAD])) {
    $! = EPERM;
    return;
  }

  # Remove the item, and return it.
  delete $item_priority{$id};
  return @{splice @$self, $item_index, 1};
}

### Remove items matching a filter.  Regrettably, this must scan the
### entire queue.  An optional count limits the number of items to
### remove, and it may shorten execution times.  Returns a list of
### references to priority/id/payload lists.  This is intended to
### return all the items matching the filter, and the function's
### behavior is undefined when $count is less than the number of
### matching items.

sub remove_items {
  my ($self, $filter, $count) = @_;
  $count = @$self unless $count;

  my @items;
  my $i = @$self;
  while ($i--) {
    if ($filter->($self->[$i]->[ITEM_PAYLOAD])) {
      my $removed_item = splice(@$self, $i, 1);
      delete $item_priority{$removed_item->[ITEM_ID]};
      unshift @items, $removed_item;
      last unless --$count;
    }
  }

  return @items;
}

### Adjust the priority of an item by a relative amount.  Adds $delta
### to the priority of the $id'd object (if it matches $filter), and
### moves it in the queue.

sub adjust_priority {
  my ($self, $id, $filter, $delta) = @_;

  my $old_priority = $item_priority{$id};
  unless (defined $old_priority) {
    $! = ESRCH;
    return;
  }

  # Find that darn item.
  my $item_index = $self->_find_item($id, $old_priority);

  # Test the item against the filter.
  unless ($filter->($self->[$item_index]->[ITEM_PAYLOAD])) {
    $! = EPERM;
    return;
  }

  # Nothing to do if the delta is zero.
  # TODO Actually we may need to ensure that the item is moved to the
  # end of its current priority bucket, since it should have "moved".
  return $self->[$item_index]->[ITEM_PRIORITY] unless $delta;

  # Remove the item, and adjust its priority.
  my $item = splice(@$self, $item_index, 1);
  my $new_priority = $item->[ITEM_PRIORITY] += $delta;
  $item_priority{$id} = $new_priority;

  $self->_reinsert_item($new_priority, $delta, $item_index, $item);
}

### Set the priority to a specific amount.  Replaces the item's
### priority with $new_priority (if it matches $filter), and moves it
### to the new location in the queue.

sub set_priority {
  my ($self, $id, $filter, $new_priority) = @_;

  my $old_priority = $item_priority{$id};
  unless (defined $old_priority) {
    $! = ESRCH;
    return;
  }

  # Nothing to do if the old and new priorities match.
  # TODO Actually we may need to ensure that the item is moved to the
  # end of its current priority bucket, since it should have "moved".
  return $new_priority if $new_priority == $old_priority;

  # Find that darn item.
  my $item_index = $self->_find_item($id, $old_priority);

  # Test the item against the filter.
  unless ($filter->($self->[$item_index]->[ITEM_PAYLOAD])) {
    $! = EPERM;
    return;
  }

  # Remove the item, and calculate the delta.
  my $item = splice(@$self, $item_index, 1);
  my $delta = $new_priority - $old_priority;
  $item->[ITEM_PRIORITY] = $item_priority{$id} = $new_priority;

  $self->_reinsert_item($new_priority, $delta, $item_index, $item);
}

### Sanity-check the results of an item insert.  Verify that it
### belongs where it was put.  Only called during debugging.

sub _dump_splice {
  my ($self, $index) = @_;
  my @return;
  my $at = $self->[$index]->[ITEM_PRIORITY];
  if ($index > 0) {
    my $before = $self->[$index-1]->[ITEM_PRIORITY];
    push @return, "before($before)";
    confess "out of order: $before should be < $at" if $before > $at;
  }
  push @return, "at($at)";
  if ($index < $#$self) {
    my $after = $self->[$index+1]->[ITEM_PRIORITY];
    push @return, "after($after)";
    my @priorities = map {$_->[ITEM_PRIORITY]} @$self;
    confess "out of order: $at should be < $after (@priorities)" if (
      $at >= $after
    );
  }
  return "@return";
}

### Reinsert an item into the queue.  It has just been removed by
### adjust_priority() or set_priority() and needs to be replaced.
### This tries to be clever by not doing more work than necessary.

sub _reinsert_item {
  my ($self, $new_priority, $delta, $item_index, $item) = @_;

  # Now insert it back.
  # The special cases are duplicates from enqueue().  We use the delta
  # (direction) of the move and the old item index to narrow down the
  # subsequent nontrivial insert if none of the special cases apply.

  # Special case: No events in the queue.  The queue IS the item.
  unless (@$self) {
    $self->[0] = $item;
    DEBUG and warn $self->_dump_splice(0);
    return $new_priority;
  }

  # Special case: The item belongs at the end of the queue.
  if ($new_priority >= $self->[-1]->[ITEM_PRIORITY]) {
    push @$self, $item;
    DEBUG and warn $self->_dump_splice(@$self-1);
    return $new_priority;
  }

  # Special case: The item belongs at the head of the queue.
  if ($new_priority < $self->[0]->[ITEM_PRIORITY]) {
    unshift @$self, $item;
    DEBUG and warn $self->_dump_splice(0);
    return $new_priority;
  }

  # Special case: There are only two items in the queue.  This item
  # naturally belongs between them.

  if (@$self == 2) {
    splice @$self, 1, 0, $item;
    DEBUG and warn $self->_dump_splice(1);
    return $new_priority;
  }

  # The item has moved towards an end of the queue, but there are a
  # lot of items into which it may be inserted.  We'll binary seek.

  my ($upper, $lower);
  if ($delta > 0) {
    $upper = $#$self; # Last index in @$self.
    $lower = $item_index;
  }
  else {
    $upper = $item_index;
    $lower = 0;
  }

  $self->_insert_item($lower, $upper, $new_priority, $item);
  return $new_priority;
}

### Peek at items that match a filter.  Returns a list of payloads
### that match the supplied coderef.

sub peek_items {
  my ($self, $filter, $count) = @_;
  $count = @$self unless $count;

  my @items;
  my $i = @$self;
  while ($i--) {
    if ($filter->($self->[$i]->[ITEM_PAYLOAD])) {
      unshift @items, $self->[$i];
      last unless --$count;
    }
  }

  return @items;
}

1;

__END__

=head1 NAME

POE::Queue::Array - a high-performance array-based priority queue

=head1 SYNOPSIS

See L<POE::Queue>.

=head1 DESCRIPTION

This class is an implementation of the abstract POE::Queue interface.
As such, its documentation may be found in L<POE::Queue>.

POE::Queue::Array implements a priority queue using Perl arrays,
splice, and copious application of cleverness.

Despite its name, POE::Queue::Array may be used as a stand-alone
priority queue without the rest of POE.

=head1 SEE ALSO

L<POE>, L<POE::Queue>

=head1 BUGS

None known.

=head1 AUTHORS & COPYRIGHTS

Please see L<POE> for more information about authors, contributors,
and POE's licensing.

=cut

# rocco // vim: ts=2 sw=2 expandtab
# TODO - Edit.