jsFind - generate index for jsFind using B-Tree


  use jsFind;
  my $t = new jsFind(B => 4);
  my $f = 1;
  foreach my $k (qw{minima ut dolorem sapiente voluptatem}) {
  	$t->B_search(Key => $k,
  		Data => {
  			"path" => {
  			t => "word $k",
  			f => $f },
  		Insert => 1,
  		Append => 1,


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:

You can also examine examples which come as tests with this module, for example t/04words.t.

jsFind methods

jsFind is mode implementing methods which you, the user, are going to use to create indexes.


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

All nodes are objects from jsFind::Node.

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


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

 	Key => 'key value',
	Data => { "path" => {
			"t" => "title of document",
			"f" => 99,
	Insert => 1,
	Append => 1,


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

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


Return B (maximum number of keys)

 my $max_size = $t->B;


Returns root node

 my $root = $t->root;


Returns if node is overfull

 if ($node->node_overfull) { something }


Returns your tree as formatted string.

 my $text = $root->to_string;

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


Create Graphviz graph of your tree

 my $dot_graph = $root->to_dot;


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


Returns number of nodes in created tree.

There is also longer version if you want to recode your data charset into different one (probably UTF-8):


Destination encoding is UTF-8 by default, so you don't have to specify it.



This is internal function to recode charset.

It will also try to decode entities in data using HTML::Entities.

jsFind::Node methods

Each node has k key-data pairs, with B <= k <= 2B, and each has 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.


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;


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 $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.


Creates new empty node

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


Test if node is empty

 if ($node->is_empty) { something }


Return $ith key from node

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


Return $ith data from node

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


Set key data pair for $ith element in node

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


Insert key/data pair in tree

  $node->kdp_insert("key value" => "data value");

No return value.


Adds new data keys and values to $ith element in node

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


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);


Test if node is leaf

 if ($node->is_leaf) { something }


Return number of keys in the node

 my $nr = $node->size;


Split node into two halves so that keys 0 .. $n-1 are in one node and keys $n+1 ... $size are in the other.

  my ($left_node, $right_node, $kdp) = $node->halves($n);


Dumps tree as string

 my $str = $root->to_string;


Recursivly walk nodes of tree


Escape <, >, & and ", and to produce valid XML


Create jsFind xml files

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

Returns number of elements created


jsFind web site

B-Trees in perl web site


Mark-Jonson Dominus <> wrote which was base for this module

Shawn P. Garbett <> wrote jsFind

Dobrica Pavlinusic <> wrote this module


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.