jsFind/trunk/jsFind.pm

package jsFind;

use 5.008004;
use strict;
use warnings;

our $VERSION = '0.01';

=head1 NAME

jsFind - generate index for jsFind using B-Tree

=head1 SYNOPSIS

  use jsFind;


=head1 DESCRIPTION

This module can be used to create index files for jsFind, powerful tool for
adding a search engine to a CDROM archive or catalog without requiring the
user to install anything. 

Main difference between this module and scripts delivered with jsFind are:

=over 5

=item *

You don't need to use swish-e to create index

=item *

You can programatically (and incrementaly) create index for jsFind

=back

=head1 METHODS

This module contains two packages C<jsFind> and C<jsFind::Node>.

=head2 jsFind methods

=cut

use Exporter 'import';
use Carp;

our @ISA = qw(Exporter);

BEGIN {
        import 'jsFind::Node';
}

=head3 new

Create new tree. Arguments are C<B> which is maximum numbers of keys in
each node and optional C<Root> node. Each root node may have child nodes.

All nodes are objects from C<jsFind::Node>.

 my $t = new jsFind(B => 4);

=cut

my $DEBUG = 1;

sub new {
  my $package = shift;
  my %ARGV = @_;
  croak "Usage: {$package}::new(B => number [, Root => root node ])"
      unless exists $ARGV{B};
  if ($ARGV{B} % 2) {
    my $B = $ARGV{B} + 1;
    carp "B must be an even number.  Using $B instead.";
    $ARGV{B} = $B;
  }
    
  my $B = $ARGV{B};
  my $Root = exists($ARGV{Root}) ? $ARGV{Root} : jsFind::Node->emptynode;
  bless { B => $B, Root => $Root } => $package;
}

=head3 B_search

Search, insert, append or replace data in B-Tree

 $t->B_search(
        Key => 'key value',
        Data => { "path" => {
                        "t" => "title of document",
                        "f" => 99,
                },
        Insert => 1,
        Append => 1,
 );

Semantics:

If key not found, insert it iff C<Insert> argument is present.

If key B<is> found, replace existing data iff C<Replace> argument
is present or add new datum to existing iff C<Append> argument is present.

=cut

sub B_search {
  my $self = shift;
  my %args = @_;
  my $cur_node = $self->root;
  my $k = $args{Key};
  my $d = $args{Data};
  my @path;

  if ($cur_node->is_empty) {    # Special case for empty root
    if ($args{Insert}) {
      $cur_node->kdp_insert($k => $d);
      return $d;
    } else {
      return undef;
    }
  }

  # Descend tree to leaf
  for (;;) {

    # Didn't hit bottom yet.

    my($there, $where) = $cur_node->locate_key($k);
    if ($there) {               # Found it!
      if ($args{Replace}) {
        $cur_node->kdp_replace($where, $k => $d);
      } elsif ($args{Append}) {
        $cur_node->kdp_append($where, $k => $d);
      }
      return $cur_node->data($where);
    }
    
    # Not here---must be in a subtree.
    
    if ($cur_node->is_leaf) {   # But there are no subtrees
      return undef unless $args{Insert}; # Search failed
      # Stuff it in
      $cur_node->kdp_insert($k => $d);
      if ($self->node_overfull($cur_node)) { # Oops--there was no room.
        $self->split_and_promote($cur_node, @path);
      } 
      return $d;
    }

    # There are subtrees, and the key is in one of them.

    push @path, [$cur_node, $where];    # Record path from root.

    # Move down to search the subtree
    $cur_node = $cur_node->subnode($where);

    # and start over.
  }                             # for (;;) ...

  croak ("How did I get here?");
}


sub split_and_promote_old {
  my $self = shift;
  my ($cur_node, @path) = @_;
  
  for (;;) {
    my ($newleft, $newright, $kdp) = $cur_node->halves($self->B / 2);
    my ($up, $where) = @{pop @path};
    if ($up) {
      $up->kdp_insert(@$kdp);
      my ($tthere, $twhere) = $up->locate_key($kdp->[0]);
      croak "Couldn't find key `$kdp->[0]' in node after just inserting it!"
          unless $tthere;
      croak "`$kdp->[0]' went into node at `$twhere' instead of expected `$where'!"
          unless $twhere == $where;
      $up->subnode($where,   $newleft);
      $up->subnode($where+1, $newright);
      return unless $self->node_overfull($up);
      $cur_node = $up;
    } else { # We're at the top; make a new root.
      my $newroot = new jsFind::Node ([$kdp->[0]], 
                                     [$kdp->[1]], 
                                     [$newleft, $newright]);
      $self->root($newroot);
      return;
    }
  }
  
}

sub split_and_promote {
  my $self = shift;
  my ($cur_node, @path) = @_;
  
  for (;;) {
    my ($newleft, $newright, $kdp) = $cur_node->halves($self->B / 2);
    my ($up, $where) = @{pop @path} if (@path);
    if ($up) {
      $up->kdp_insert(@$kdp);
      if ($DEBUG) {
        my ($tthere, $twhere) = $up->locate_key($kdp->[0]);
        croak "Couldn't find key `$kdp->[0]' in node after just inserting it!"
          unless $tthere;
        croak "`$kdp->[0]' went into node at `$twhere' instead of expected `$where'!"
          unless $twhere == $where;
      }
      $up->subnode($where,   $newleft);
      $up->subnode($where+1, $newright);
      return unless $self->node_overfull($up);
      $cur_node = $up;
    } else { # We're at the top; make a new root.
      my $newroot = new jsFind::Node([$kdp->[0]], 
                                     [$kdp->[1]], 
                                     [$newleft, $newright]);
      $self->root($newroot);
      return;
    }
  }
}

=head3 B

Return B (maximum number of keys)

 my $max_size = $t->B;

=cut

sub B {
  $_[0]{B};
}

=head3 root

Returns root node

 my $root = $t->root;

=cut

sub root {
  my ($self, $newroot) = @_;
  $self->{Root} = $newroot if defined $newroot;
  $self->{Root};
}

=head3 node_overfull

Returns if node is overfull

 if ($node->node_overfull) { something }

=cut

sub node_overfull {
  my $self = shift;
  my $node = shift;
  $node->size > $self->B;
}

=head3 to_string

Returns your tree as formatted string.

 my $text = $root->to_string;

Mostly usefull for debugging as output leaves much to be desired.

=cut

sub to_string {
  $_[0]->root->to_string;
}

=head3 to_dot

Create Graphviz graph of your tree

 my $dot_graph = $root->to_dot;

=cut

sub to_dot {
        my $self = shift;

        my $dot = qq/digraph dns {\nrankdir=LR;\n/;
        $dot .= $self->root->to_dot;
        $dot .= qq/\n}\n/;

        return $dot;
}

=head3 to_jsfind

Create xml index files for jsFind. This should be called after
your B-Tree has been filled with data.

 $root->to_jsfind('/full/path/to/index/dir/');

Returns number of nodes in created tree.

=cut

sub to_jsfind {
        my $self = shift;

        my $path = shift || confess "to_jsfind need path to your index!";

        $path .= "/" if ($path =~ /\/$/);
        carp "can't create index in '$path': $!" if (! -w $path);

        return $self->root->to_jsfind($path,"0");
}


# private, default cmd function
sub default_cmp {
  $_[0] cmp $_[1];
}

#####################################################################

=head2 jsFind::Node methods

Each node has C<k> key-data pairs, with C<B> <= C<k> <= C<2B>, and 
each has C<k+1> subnodes, which might be null.

The node is a blessed reference to a list with three elements:

  ($keylist, $datalist, $subnodelist)

each is a reference to a list list.

The null node is represented by a blessed reference to an empty list.

=cut

package jsFind::Node;

use warnings;
use strict;

use Carp;
use File::Path;

my $KEYS = 0;
my $DATA = 1;
my $SUBNODES = 2;

=head3 new

Create New node

 my $node = new jsFind::Node ($keylist, $datalist, $subnodelist);

You can also mit argument list to create empty node.

 my $empty_node = new jsFind::Node;

=cut

sub new {
  my $self = shift;
  my $package = ref $self || $self;
  croak "Internal error:  jsFind::Node::new called with wrong number of arguments."
      unless @_ == 3 || @_ == 0;
  bless [@_] => $package;
}

=head3 locate_key

Locate key in node using linear search. This should probably be replaced
by binary search for better performance.

 my ($found, $index) = $node->locate_key($key, $cmp_coderef);

Argument C<$cmp_coderef> is optional reference to custom comparison
operator.

Returns (1, $index) if $key[$index] eq $key.

Returns (0, $index) if key could be found in $subnode[$index].

In scalar context, just returns 1 or 0.

=cut

sub locate_key {
  # Use linear search for testing, replace with binary search.
  my $self = shift;
  my $key = shift;
  my $cmp = shift || \&jsFind::default_cmp;
  my $i;
  my $cmp_result;
  my $N = $self->size;
  for ($i = 0; $i < $N; $i++) {
    $cmp_result = &$cmp($key, $self->key($i));
    last if $cmp_result <= 0;
  }
  
  # $i is now the index of the first node-key greater than $key
  # or $N if there is no such.  $cmp_result is 0 iff the key was found.
  (!$cmp_result, $i);
}


=head3 emptynode

Creates new empty node

 $node = $root->emptynode;
 $new_node = $node->emptynode;

=cut

sub emptynode {
  new($_[0]);                   # Pass package name, but not anything else.
}

=head3 is_empty

Test if node is empty

 if ($node->is_empty) { something }

=cut

# undef is empty; so is a blessed empty list.
sub is_empty {
  my $self = shift;
  !defined($self) || $#$self < 0;
}

=head3 key

Return C<$i>th key from node

 my $key = $node->key($i);

=cut

sub key {
#  my ($self, $n) = @_;
#  $self->[$KEYS][$n];

#       speedup
   $_[0]->[$KEYS][$_[1]];
}

=head3 data

Return C<$i>th data from node

 my $data = $node->data($i);

=cut

sub data {
  my ($self, $n) = @_;
  $self->[$DATA][$n];
}

=head3 kdp_replace

Set key data pair for C<$i>th element in node

 $node->kdp_replace($i, "key value" => {
        "data key 1" => "data value 1",
        "data key 2" => "data value 2",
 };

=cut

sub kdp_replace {
  my ($self, $n, $k => $d) = @_;
  if (defined $k) {
    $self->[$KEYS][$n] = $k;
    $self->[$DATA][$n] = $d;
  }
  [$self->[$KEYS][$n], 
   $self->[$DATA][$n]];
}

=head3 kdp_insert

 # No return value.

=cut

sub kdp_insert {
  my $self = shift;
  my ($k => $d) = @_;
  my ($there, $where) = $self->locate_key($k) unless $self->is_empty;

  if ($there) { croak("Tried to insert `$k => $d' into node where `$k' was already present."); }

  # undef fix
  $where ||= 0;

  splice(@{$self->[$KEYS]}, $where, 0, $k);
  splice(@{$self->[$DATA]}, $where, 0, $d);
  splice(@{$self->[$SUBNODES]}, $where, 0, undef);
}

=head3 kdp_append

Adds new data keys and values to C<$i>th element in node

 $node->kdp_append($i, "key value" => {
        "added data key" => "added data value",
 };

=cut

sub kdp_append {
  my ($self, $n, $k => $d) = @_;
  if (defined $k) {
    $self->[$KEYS][$n] = $k;
    my ($kv,$dv) = %{$d};
    $self->[$DATA][$n]->{$kv} = $dv;
  }
  [$self->[$KEYS][$n], 
   $self->[$DATA][$n]];
}

=head3 subnode

Set new or return existing subnode

 # return 4th subnode
 my $my_node = $node->subnode(4);

 # create new subnode 5 from $my_node
 $node->subnode(5, $my_node);

=cut

sub subnode {
  my ($self, $n, $newnode) = @_;
  $self->[$SUBNODES][$n] = $newnode if defined $newnode;
  $self->[$SUBNODES][$n];
}

=head3 is_leaf

Test if node is leaf

 if ($node->is_leaf) { something }

=cut

sub is_leaf {
  my $self = shift;
  ! defined $self->[$SUBNODES][0]; # undefined subnode means leaf node.
}

=head3 size

Return number of keys in the node

 my $nr = $node->size;

=cut

sub size {
  my $self = shift;
  return scalar(@{$self->[$KEYS]});
}

=head3 halves

 # Accept an index $n
 # Divide into two nodes so that keys 0 .. $n-1 are in one node
 # and keys $n+1 ... $size are in the other.

=cut

sub halves {
  my $self = shift;
  my $n = shift;
  my $s = $self->size;
  my @right;
  my @left;

  $left[$KEYS] = [@{$self->[$KEYS]}[0 .. $n-1]];
  $left[$DATA] = [@{$self->[$DATA]}[0 .. $n-1]];
  $left[$SUBNODES] = [@{$self->[$SUBNODES]}[0 .. $n]];

  $right[$KEYS] = [@{$self->[$KEYS]}[$n+1 .. $s-1]];
  $right[$DATA] = [@{$self->[$DATA]}[$n+1 .. $s-1]];
  $right[$SUBNODES] = [@{$self->[$SUBNODES]}[$n+1 .. $s]];

  my @middle = ($self->[$KEYS][$n], $self->[$DATA][$n]);

  ($self->new(@left), $self->new(@right), \@middle);
}

=head3 to_string

Dumps tree as string

 my $str = $root->to_string;

=cut

sub to_string {
  my $self = shift;
  my $indent = shift || 0;
  my $I = ' ' x $indent;
  return '' if $self->is_empty;
  my ($k, $d, $s) = @$self;
  my $result = '';
  $result .= defined($s->[0]) ? $s->[0]->to_string($indent+2) : '';
  my $N = $self->size;
  my $i;
  for ($i = 0; $i < $N; $i++) {
#    $result .= $I . "$k->[$i] => $d->[$i]\n";
    $result .= $I . "$k->[$i]\n";
    $result .= defined($s->[$i+1]) ? $s->[$i+1]->to_string($indent+2) : '';
  }
  $result;
}

=begin comment

use Data::Dumper;

sub to_string {
  my $self = shift;
  my $indent = shift || 0;
  my $path = shift || '0';
  return '' if $self->is_empty;
  my ($k, $d, $s) = @$self;
  my $result = '';
  $result .= defined($s->[0]) ? $s->[0]->to_string($indent+1,"$path/0") : '';
  my $N = $self->size;
  for (my $i = 0; $i < $N; $i++) {
        my $dump = Dumper($d->[$i]);
        $dump =~ s/[\n\r\s]+/ /gs;
        $dump =~ s/\$VAR1\s*=\s*//;
    $result .= sprintf("%-5s [%2d] %2s: %s => %s\n", $path, $i, $indent, $k->[$i], $dump);
    $result .= defined($s->[$i+1]) ? $s->[$i+1]->to_string($indent+1,"$path/$i") : '';
  }
  $result;
}

=end comment

=head3 to_dot

Recursivly walk nodes of tree

=cut

sub to_dot {
        my $self = shift;
        my $parent = shift;

        return '' if $self->is_empty;

        my $dot = '';

        my ($k, $d, $s) = @$self;
        my $N = $self->size;

        my @dot_keys;

        my $node_name = $parent || '_';
        $node_name =~ s/\W+//g;
        $node_name .= " [$N]";

        for (my $i = 0; $i <= $N; $i++) {
                if (my $key = $k->[$i]) {
                        push @dot_keys, qq{<$i>$key};
                }
                $dot .= $s->[$i]->to_dot(qq{"$node_name":$i}) if ($s->[$i]);
        }
        push @dot_keys, qq{<$N>...} if (! $self->is_leaf);

        my $label = join("|",@dot_keys);
        $dot .= qq{"$node_name" [ shape=record, label="$label" ];\n};

        $dot .= qq{$parent -> "$node_name";\n} if ($parent);

        $dot;
}

=head3 to_jsfind

Create jsFind xml files

 my $nr=$tree->to_dot('/path/to/index','0');

Returns number of elements created

=cut

sub to_jsfind {
        my $self = shift;
        my ($path,$file) = @_;

        return 0 if $self->is_empty;

        my $nr_keys = 0;

        my ($k, $d, $s) = @$self;
        my $N = $self->size;

        my ($key_xml, $data_xml) = ("<n>","<d>");

        for (my $i = 0; $i <= $N; $i++) {
                my $key = lc($k->[$i]);

                if ($key) {
                        $key_xml .= qq{<k>$key</k>};
                        $data_xml .= qq{<e>};
        #use Data::Dumper;
        #print Dumper($d->[$i]);
                        foreach my $path (keys %{$d->[$i]}) {
                                $data_xml .= '<l f="'.($d->[$i]->{$path}->{'f'} || 1).'" t="'.($d->[$i]->{$path}->{'t'} || 'no title').'">'.$path.'</l>';
                                $nr_keys++;
                        }
                        $data_xml .= qq{</e>};
                }

                $nr_keys += $s->[$i]->to_jsfind("$path/$file","$i") if ($s->[$i]);
        }

        $key_xml .= "</n>";
        $data_xml .= "</d>";

        if (! -e $path) {
                mkpath($path) || croak "can't create dir '$path': $!";
        }

        open(K, "> ${path}/${file}.xml") || croak "can't open '$path/$file.xml': $!";
        open(D, "> ${path}/_${file}.xml") || croak "can't open '$path/_$file.xml': $!";

        print K $key_xml;
        print D $data_xml;

        close(K);
        close(D);

        return $nr_keys;
}

1;
__END__

=head1 SEE ALSO

jsFind web site L<http://www.elucidsoft.net/projects/jsfind/>

B-Trees in perl web site L<http://perl.plover.com/BTree/>

=head1 AUTHORS

Mark-Jonson Dominus E<lt>mjd@pobox.comE<gt> wrote C<BTree.pm> which was
base for this module

Shawn P. Garbett E<lt>shawn@elucidsoft.netE<gt> wrote jsFind

Dobrica Pavlinusic E<lt>dpavlin@rot13.orgE<gt> wrote this module

=head1 COPYRIGHT AND LICENSE

Copyright (C) 2004 by Dobrica Pavlinusic

This program is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by the Free
Software Foundation; either version 2 of the License, or (at your option)
any later version. This program is distributed in the hope that it will be
useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
Public License for more details.

=cut
1	dpavlin	1	package jsFind;
2
3			use 5.008004;
4			use strict;
5			use warnings;
6
7			our $VERSION = '0.01';
8
9			=head1 NAME
10
11			jsFind - generate index for jsFind using B-Tree
12
13			=head1 SYNOPSIS
14
15			use jsFind;
16
17
18
19			=head1 DESCRIPTION
20
21			This module can be used to create index files for jsFind, powerful tool for
22			adding a search engine to a CDROM archive or catalog without requiring the
23			user to install anything.
24
25			Main difference between this module and scripts delivered with jsFind are:
26
27			=over 5
28
29			=item *
30
31			You don't need to use swish-e to create index
32
33			=item *
34
35			You can programatically (and incrementaly) create index for jsFind
36
37			=back
38
39			=head1 METHODS
40
41			This module contains two packages C<jsFind> and C<jsFind::Node>.
42
43			=head2 jsFind methods
44
45			=cut
46
47			use Exporter 'import';
48			use Carp;
49
50			our @ISA = qw(Exporter);
51
52			BEGIN {
53			import 'jsFind::Node';
54			}
55
56			=head3 new
57
58			Create new tree. Arguments are C<B> which is maximum numbers of keys in
59			each node and optional C<Root> node. Each root node may have child nodes.
60
61			All nodes are objects from C<jsFind::Node>.
62
63			my $t = new jsFind(B => 4);
64
65			=cut
66
67			my $DEBUG = 1;
68
69			sub new {
70			my $package = shift;
71			my %ARGV = @_;
72			croak "Usage: {$package}::new(B => number [, Root => root node ])"
73			unless exists $ARGV{B};
74			if ($ARGV{B} % 2) {
75			my $B = $ARGV{B} + 1;
76			carp "B must be an even number. Using $B instead.";
77			$ARGV{B} = $B;
78			}
79
80			my $B = $ARGV{B};
81			my $Root = exists($ARGV{Root}) ? $ARGV{Root} : jsFind::Node->emptynode;
82			bless { B => $B, Root => $Root } => $package;
83			}
84
85			=head3 B_search
86
87			Search, insert, append or replace data in B-Tree
88
89	dpavlin	5	$t->B_search(
90			Key => 'key value',
91			Data => { "path" => {
92			"t" => "title of document",
93			"f" => 99,
94			},
95			Insert => 1,
96			Append => 1,
97			);
98	dpavlin	1
99			Semantics:
100
101			If key not found, insert it iff C<Insert> argument is present.
102
103			If key B<is> found, replace existing data iff C<Replace> argument
104			is present or add new datum to existing iff C<Append> argument is present.
105
106			=cut
107
108			sub B_search {
109			my $self = shift;
110			my %args = @_;
111			my $cur_node = $self->root;
112			my $k = $args{Key};
113			my $d = $args{Data};
114			my @path;
115
116			if ($cur_node->is_empty) { # Special case for empty root
117			if ($args{Insert}) {
118			$cur_node->kdp_insert($k => $d);
119			return $d;
120			} else {
121			return undef;
122			}
123			}
124
125			# Descend tree to leaf
126			for (;;) {
127
128			# Didn't hit bottom yet.
129
130			my($there, $where) = $cur_node->locate_key($k);
131			if ($there) { # Found it!
132			if ($args{Replace}) {
133			$cur_node->kdp_replace($where, $k => $d);
134			} elsif ($args{Append}) {
135			$cur_node->kdp_append($where, $k => $d);
136			}
137			return $cur_node->data($where);
138			}
139
140			# Not here---must be in a subtree.
141
142			if ($cur_node->is_leaf) { # But there are no subtrees
143			return undef unless $args{Insert}; # Search failed
144			# Stuff it in
145			$cur_node->kdp_insert($k => $d);
146			if ($self->node_overfull($cur_node)) { # Oops--there was no room.
147			$self->split_and_promote($cur_node, @path);
148			}
149			return $d;
150			}
151
152			# There are subtrees, and the key is in one of them.
153
154			push @path, [$cur_node, $where]; # Record path from root.
155
156			# Move down to search the subtree
157			$cur_node = $cur_node->subnode($where);
158
159			# and start over.
160			} # for (;;) ...
161
162			croak ("How did I get here?");
163			}
164
165
166
167			sub split_and_promote_old {
168			my $self = shift;
169			my ($cur_node, @path) = @_;
170
171			for (;;) {
172			my ($newleft, $newright, $kdp) = $cur_node->halves($self->B / 2);
173			my ($up, $where) = @{pop @path};
174			if ($up) {
175			$up->kdp_insert(@$kdp);
176			my ($tthere, $twhere) = $up->locate_key($kdp->[0]);
177			croak "Couldn't find key `$kdp->[0]' in node after just inserting it!"
178			unless $tthere;
179			croak "`$kdp->[0]' went into node at `$twhere' instead of expected `$where'!"
180			unless $twhere == $where;
181			$up->subnode($where, $newleft);
182			$up->subnode($where+1, $newright);
183			return unless $self->node_overfull($up);
184			$cur_node = $up;
185			} else { # We're at the top; make a new root.
186			my $newroot = new jsFind::Node ([$kdp->[0]],
187			[$kdp->[1]],
188			[$newleft, $newright]);
189			$self->root($newroot);
190			return;
191			}
192			}
193
194			}
195
196			sub split_and_promote {
197			my $self = shift;
198			my ($cur_node, @path) = @_;
199
200			for (;;) {
201			my ($newleft, $newright, $kdp) = $cur_node->halves($self->B / 2);
202			my ($up, $where) = @{pop @path} if (@path);
203			if ($up) {
204			$up->kdp_insert(@$kdp);
205			if ($DEBUG) {
206			my ($tthere, $twhere) = $up->locate_key($kdp->[0]);
207			croak "Couldn't find key `$kdp->[0]' in node after just inserting it!"
208			unless $tthere;
209			croak "`$kdp->[0]' went into node at `$twhere' instead of expected `$where'!"
210			unless $twhere == $where;
211			}
212			$up->subnode($where, $newleft);
213			$up->subnode($where+1, $newright);
214			return unless $self->node_overfull($up);
215			$cur_node = $up;
216			} else { # We're at the top; make a new root.
217			my $newroot = new jsFind::Node([$kdp->[0]],
218			[$kdp->[1]],
219			[$newleft, $newright]);
220			$self->root($newroot);
221			return;
222			}
223			}
224			}
225
226			=head3 B
227
228			Return B (maximum number of keys)
229
230			my $max_size = $t->B;
231
232			=cut
233
234			sub B {
235			$_[0]{B};
236			}
237
238			=head3 root
239
240			Returns root node
241
242			my $root = $t->root;
243
244			=cut
245
246			sub root {
247			my ($self, $newroot) = @_;
248			$self->{Root} = $newroot if defined $newroot;
249			$self->{Root};
250			}
251
252			=head3 node_overfull
253
254			Returns if node is overfull
255
256			if ($node->node_overfull) { something }
257
258			=cut
259
260			sub node_overfull {
261			my $self = shift;
262			my $node = shift;
263			$node->size > $self->B;
264			}
265
266			=head3 to_string
267
268			Returns your tree as formatted string.
269
270			my $text = $root->to_string;
271
272			Mostly usefull for debugging as output leaves much to be desired.
273
274			=cut
275
276			sub to_string {
277			$_[0]->root->to_string;
278			}
279
280			=head3 to_dot
281
282			Create Graphviz graph of your tree
283
284			my $dot_graph = $root->to_dot;
285
286			=cut
287
288			sub to_dot {
289			my $self = shift;
290
291			my $dot = qq/digraph dns {\nrankdir=LR;\n/;
292			$dot .= $self->root->to_dot;
293			$dot .= qq/\n}\n/;
294
295			return $dot;
296			}
297
298			=head3 to_jsfind
299
300			Create xml index files for jsFind. This should be called after
301			your B-Tree has been filled with data.
302
303			$root->to_jsfind('/full/path/to/index/dir/');
304
305			Returns number of nodes in created tree.
306
307			=cut
308
309			sub to_jsfind {
310			my $self = shift;
311
312			my $path = shift \|\| confess "to_jsfind need path to your index!";
313
314			$path .= "/" if ($path =~ /\/$/);
315			carp "can't create index in '$path': $!" if (! -w $path);
316
317			return $self->root->to_jsfind($path,"0");
318			}
319
320
321			# private, default cmd function
322			sub default_cmp {
323			$_[0] cmp $_[1];
324			}
325
326			#####################################################################
327
328			=head2 jsFind::Node methods
329
330			Each node has C<k> key-data pairs, with C<B> <= C<k> <= C<2B>, and
331			each has C<k+1> subnodes, which might be null.
332
333			The node is a blessed reference to a list with three elements:
334
335			($keylist, $datalist, $subnodelist)
336
337			each is a reference to a list list.
338
339			The null node is represented by a blessed reference to an empty list.
340
341			=cut
342
343			package jsFind::Node;
344
345			use warnings;
346			use strict;
347
348			use Carp;
349			use File::Path;
350
351			my $KEYS = 0;
352			my $DATA = 1;
353			my $SUBNODES = 2;
354
355			=head3 new
356
357			Create New node
358
359			my $node = new jsFind::Node ($keylist, $datalist, $subnodelist);
360
361			You can also mit argument list to create empty node.
362
363			my $empty_node = new jsFind::Node;
364
365			=cut
366
367			sub new {
368			my $self = shift;
369			my $package = ref $self \|\| $self;
370			croak "Internal error: jsFind::Node::new called with wrong number of arguments."
371			unless @_ == 3 \|\| @_ == 0;
372			bless [@_] => $package;
373			}
374
375			=head3 locate_key
376
377			Locate key in node using linear search. This should probably be replaced
378			by binary search for better performance.
379
380			my ($found, $index) = $node->locate_key($key, $cmp_coderef);
381
382			Argument C<$cmp_coderef> is optional reference to custom comparison
383			operator.
384
385			Returns (1, $index) if $key[$index] eq $key.
386
387			Returns (0, $index) if key could be found in $subnode[$index].
388
389			In scalar context, just returns 1 or 0.
390
391			=cut
392
393			sub locate_key {
394			# Use linear search for testing, replace with binary search.
395			my $self = shift;
396			my $key = shift;
397			my $cmp = shift \|\| \&jsFind::default_cmp;
398			my $i;
399			my $cmp_result;
400			my $N = $self->size;
401			for ($i = 0; $i < $N; $i++) {
402			$cmp_result = &$cmp($key, $self->key($i));
403			last if $cmp_result <= 0;
404			}
405
406			# $i is now the index of the first node-key greater than $key
407			# or $N if there is no such. $cmp_result is 0 iff the key was found.
408			(!$cmp_result, $i);
409			}
410
411
412			=head3 emptynode
413
414			Creates new empty node
415
416			$node = $root->emptynode;
417			$new_node = $node->emptynode;
418
419			=cut
420
421			sub emptynode {
422			new($_[0]); # Pass package name, but not anything else.
423			}
424
425			=head3 is_empty
426
427			Test if node is empty
428
429			if ($node->is_empty) { something }
430
431			=cut
432
433			# undef is empty; so is a blessed empty list.
434			sub is_empty {
435			my $self = shift;
436			!defined($self) \|\| $#$self < 0;
437			}
438
439			=head3 key
440
441			Return C<$i>th key from node
442
443			my $key = $node->key($i);
444
445			=cut
446
447			sub key {
448			# my ($self, $n) = @_;
449			# $self->[$KEYS][$n];
450
451			# speedup
452			$_[0]->[$KEYS][$_[1]];
453			}
454
455			=head3 data
456
457			Return C<$i>th data from node
458
459			my $data = $node->data($i);
460
461			=cut
462
463			sub data {
464			my ($self, $n) = @_;
465			$self->[$DATA][$n];
466			}
467
468			=head3 kdp_replace
469
470			Set key data pair for C<$i>th element in node
471
472			$node->kdp_replace($i, "key value" => {
473			"data key 1" => "data value 1",
474			"data key 2" => "data value 2",
475			};
476
477			=cut
478
479			sub kdp_replace {
480			my ($self, $n, $k => $d) = @_;
481			if (defined $k) {
482			$self->[$KEYS][$n] = $k;
483			$self->[$DATA][$n] = $d;
484			}
485			[$self->[$KEYS][$n],
486			$self->[$DATA][$n]];
487			}
488
489			=head3 kdp_insert
490
491			# No return value.
492
493			=cut
494
495			sub kdp_insert {
496			my $self = shift;
497			my ($k => $d) = @_;
498			my ($there, $where) = $self->locate_key($k) unless $self->is_empty;
499
500			if ($there) { croak("Tried to insert `$k => $d' into node where `$k' was already present."); }
501
502			# undef fix
503			$where \|\|= 0;
504
505			splice(@{$self->[$KEYS]}, $where, 0, $k);
506			splice(@{$self->[$DATA]}, $where, 0, $d);
507			splice(@{$self->[$SUBNODES]}, $where, 0, undef);
508			}
509
510			=head3 kdp_append
511
512			Adds new data keys and values to C<$i>th element in node
513
514			$node->kdp_append($i, "key value" => {
515			"added data key" => "added data value",
516			};
517
518			=cut
519
520			sub kdp_append {
521			my ($self, $n, $k => $d) = @_;
522			if (defined $k) {
523			$self->[$KEYS][$n] = $k;
524			my ($kv,$dv) = %{$d};
525			$self->[$DATA][$n]->{$kv} = $dv;
526			}
527			[$self->[$KEYS][$n],
528			$self->[$DATA][$n]];
529			}
530
531			=head3 subnode
532
533			Set new or return existing subnode
534
535			# return 4th subnode
536			my $my_node = $node->subnode(4);
537
538			# create new subnode 5 from $my_node
539			$node->subnode(5, $my_node);
540
541			=cut
542
543			sub subnode {
544			my ($self, $n, $newnode) = @_;
545			$self->[$SUBNODES][$n] = $newnode if defined $newnode;
546			$self->[$SUBNODES][$n];
547			}
548
549			=head3 is_leaf
550
551			Test if node is leaf
552
553			if ($node->is_leaf) { something }
554
555			=cut
556
557			sub is_leaf {
558			my $self = shift;
559			! defined $self->[$SUBNODES][0]; # undefined subnode means leaf node.
560			}
561
562			=head3 size
563
564			Return number of keys in the node
565
566			my $nr = $node->size;
567
568			=cut
569
570			sub size {
571			my $self = shift;
572			return scalar(@{$self->[$KEYS]});
573			}
574
575			=head3 halves
576
577			# Accept an index $n
578			# Divide into two nodes so that keys 0 .. $n-1 are in one node
579			# and keys $n+1 ... $size are in the other.
580
581			=cut
582
583			sub halves {
584			my $self = shift;
585			my $n = shift;
586			my $s = $self->size;
587			my @right;
588			my @left;
589
590			$left[$KEYS] = [@{$self->[$KEYS]}[0 .. $n-1]];
591			$left[$DATA] = [@{$self->[$DATA]}[0 .. $n-1]];
592			$left[$SUBNODES] = [@{$self->[$SUBNODES]}[0 .. $n]];
593
594			$right[$KEYS] = [@{$self->[$KEYS]}[$n+1 .. $s-1]];
595			$right[$DATA] = [@{$self->[$DATA]}[$n+1 .. $s-1]];
596			$right[$SUBNODES] = [@{$self->[$SUBNODES]}[$n+1 .. $s]];
597
598			my @middle = ($self->[$KEYS][$n], $self->[$DATA][$n]);
599
600			($self->new(@left), $self->new(@right), \@middle);
601			}
602
603			=head3 to_string
604
605			Dumps tree as string
606
607			my $str = $root->to_string;
608
609			=cut
610
611			sub to_string {
612			my $self = shift;
613			my $indent = shift \|\| 0;
614			my $I = ' ' x $indent;
615			return '' if $self->is_empty;
616			my ($k, $d, $s) = @$self;
617			my $result = '';
618			$result .= defined($s->[0]) ? $s->[0]->to_string($indent+2) : '';
619			my $N = $self->size;
620			my $i;
621			for ($i = 0; $i < $N; $i++) {
622			# $result .= $I . "$k->[$i] => $d->[$i]\n";
623			$result .= $I . "$k->[$i]\n";
624			$result .= defined($s->[$i+1]) ? $s->[$i+1]->to_string($indent+2) : '';
625			}
626			$result;
627			}
628
629			=begin comment
630
631			use Data::Dumper;
632
633			sub to_string {
634			my $self = shift;
635			my $indent = shift \|\| 0;
636			my $path = shift \|\| '0';
637			return '' if $self->is_empty;
638			my ($k, $d, $s) = @$self;
639			my $result = '';
640			$result .= defined($s->[0]) ? $s->[0]->to_string($indent+1,"$path/0") : '';
641			my $N = $self->size;
642			for (my $i = 0; $i < $N; $i++) {
643			my $dump = Dumper($d->[$i]);
644			$dump =~ s/[\n\r\s]+/ /gs;
645			$dump =~ s/\$VAR1\s=\s//;
646			$result .= sprintf("%-5s [%2d] %2s: %s => %s\n", $path, $i, $indent, $k->[$i], $dump);
647			$result .= defined($s->[$i+1]) ? $s->[$i+1]->to_string($indent+1,"$path/$i") : '';
648			}
649			$result;
650			}
651
652			=end comment
653
654			=head3 to_dot
655
656			Recursivly walk nodes of tree
657
658			=cut
659
660			sub to_dot {
661			my $self = shift;
662			my $parent = shift;
663
664			return '' if $self->is_empty;
665
666			my $dot = '';
667
668			my ($k, $d, $s) = @$self;
669			my $N = $self->size;
670
671			my @dot_keys;
672
673			my $node_name = $parent \|\| '_';
674			$node_name =~ s/\W+//g;
675			$node_name .= " [$N]";
676
677			for (my $i = 0; $i <= $N; $i++) {
678			if (my $key = $k->[$i]) {
679			push @dot_keys, qq{<$i>$key};
680			}
681			$dot .= $s->[$i]->to_dot(qq{"$node_name":$i}) if ($s->[$i]);
682			}
683			push @dot_keys, qq{<$N>...} if (! $self->is_leaf);
684
685			my $label = join("\|",@dot_keys);
686			$dot .= qq{"$node_name" [ shape=record, label="$label" ];\n};
687
688			$dot .= qq{$parent -> "$node_name";\n} if ($parent);
689
690			$dot;
691			}
692
693			=head3 to_jsfind
694
695			Create jsFind xml files
696
697			my $nr=$tree->to_dot('/path/to/index','0');
698
699			Returns number of elements created
700
701			=cut
702
703			sub to_jsfind {
704			my $self = shift;
705			my ($path,$file) = @_;
706
707			return 0 if $self->is_empty;
708
709			my $nr_keys = 0;
710
711			my ($k, $d, $s) = @$self;
712			my $N = $self->size;
713
714			my ($key_xml, $data_xml) = ("<n>","<d>");
715
716			for (my $i = 0; $i <= $N; $i++) {
717			my $key = lc($k->[$i]);
718
719			if ($key) {
720			$key_xml .= qq{<k>$key</k>};
721			$data_xml .= qq{<e>};
722			#use Data::Dumper;
723			#print Dumper($d->[$i]);
724			foreach my $path (keys %{$d->[$i]}) {
725			$data_xml .= '<l f="'.($d->[$i]->{$path}->{'f'} \|\| 1).'" t="'.($d->[$i]->{$path}->{'t'} \|\| 'no title').'">'.$path.'</l>';
726			$nr_keys++;
727			}
728			$data_xml .= qq{</e>};
729			}
730
731			$nr_keys += $s->[$i]->to_jsfind("$path/$file","$i") if ($s->[$i]);
732			}
733
734			$key_xml .= "</n>";
735			$data_xml .= "</d>";
736
737			if (! -e $path) {
738			mkpath($path) \|\| croak "can't create dir '$path': $!";
739			}
740
741			open(K, "> ${path}/${file}.xml") \|\| croak "can't open '$path/$file.xml': $!";
742			open(D, "> ${path}/_${file}.xml") \|\| croak "can't open '$path/_$file.xml': $!";
743
744			print K $key_xml;
745			print D $data_xml;
746
747			close(K);
748			close(D);
749
750			return $nr_keys;
751			}
752
753			1;
754			__END__
755
756			=head1 SEE ALSO
757
758			jsFind web site L<http://www.elucidsoft.net/projects/jsfind/>
759
760			B-Trees in perl web site L<http://perl.plover.com/BTree/>
761
762			=head1 AUTHORS
763
764			Mark-Jonson Dominus E<lt>mjd@pobox.comE<gt> wrote C<BTree.pm> which was
765			base for this module
766
767			Shawn P. Garbett E<lt>shawn@elucidsoft.netE<gt> wrote jsFind
768
769			Dobrica Pavlinusic E<lt>dpavlin@rot13.orgE<gt> wrote this module
770
771			=head1 COPYRIGHT AND LICENSE
772
773			Copyright (C) 2004 by Dobrica Pavlinusic
774
775			This program is free software; you can redistribute it and/or modify it
776			under the terms of the GNU General Public License as published by the Free
777			Software Foundation; either version 2 of the License, or (at your option)
778			any later version. This program is distributed in the hope that it will be
779			useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
780			MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
781			Public License for more details.
782
783			=cut