bfilter/trunk/bfilter.js

/*
   Fast filtering function using pre-sorted list elements
   Dobrica Pavlinusic, dpavlin@rot13.org 2004-09-06
   Matko Andjelinic, matko.andjelinic@gmail.com 2004-09-09 (contributed OO implementation)
*/


function BFilter(arr) {
        this.id_cache = Array();
        // total number of hits
        this.hits = 0;
        this.html_pre = '<a href="';
        this.html_mid = '">';
        this.html_post = '</a><br/>';
        this.html_full_pre = '';
        this.html_full_post = '';

        if (! arr) {
                this.debug("ERROR: can't search empty array");
                return;
        }

        this.arr = arr;
        this.debug("index has "+this.arr.length+" parts");

        if (! arr.min_len) {
                this.results("ERROR: index structure problem");
                return;
        } else {
                this.min_len = arr.min_len;
        }

        this.debug("index part has "+this.min_len+" parts");

        this.show_status();

}

BFilter.prototype.element_id = function (id,no_alert) {
        if (this.id_cache[id]) {
                return this.id_cache[id];
        } else {
                var el = document.getElementById(id);
                if (el) {
                        this.id_cache[id] = el;
                        return el;
                } else {
                        if (! no_alert) {
                                alert("can't find element id: "+id);
                        } else {
                                // don't look it up again
                                this.id_cache[id] = null;
                        }
                }
        }
}


BFilter.prototype.show_status = function (status) {
        var html;
        if (this.hits > 0) {
                html = "shown "+this.hits+" entries";
        } else {
                html = "no results";
        }
        if (! status) {
                html = "Enter "+this.min_len+" letter"+(this.min_len == 1 ? '' : 's')+" to filter entries";
                status = "";
        }

        var el = this.element_id("status");
        el.innerHTML = html+status+"\n";
}

BFilter.prototype.results = function (html,clean) {

        if (! html) { html = ""; }

        // results_div.style.cursor = 'wait'; // 'auto'
        var results_div = this.element_id("results");
        if (clean) {
                results_div.innerHTML = html + "\n";
        } else {
                results_div.innerHTML += this.html_full_pre + html +"\n" + this.html_full_post;
        }
}


BFilter.prototype.debug = function (html) {

        //return;

        // check if debugging is on
        if (! html) { return 1; }

        var debug_div = this.element_id("debug",1);
        if (! debug_div) { return; }

        if (debug_div.innerHTML) {
                debug_div.innerHTML =+ html + "x<br>\n";
        } else {
                debug_div.innerHTML = html + "y<br>\n";
        }
}


// modified binary search to find first element with substring
BFilter.prototype.binarySearch = function (arr, find) {
        if (!arr || typeof (find) == "undefined" || !arr.length) {
                return null;
        }
        var low = 0;
        var high = arr.length - 1;
        var middlearr = parseInt(arr.length / 2);
        var lastTry;
        while (low <= high) {
                var mid = (low + high) / 2;
                var aTry = (mid < 1) ? 0 : parseInt(mid);
        
                var curr = arr[aTry][1].substr(0,find.length).toLowerCase();
                this.debug("low="+low+" high="+high+" lastTry="+lastTry+" "+aTry+": "+curr+"<br>");
                if (curr < find) {
                        low = aTry + 1;
                        continue;
                }
                if (curr > find) {
                        high = aTry - 1;
                        continue;
                }
                if (curr == find) {
                        high = aTry - 1;
                        lastTry = aTry;
                        continue;
                }
                return aTry;
        }
        this.debug("lastTry="+lastTry+"<br>");

        if (typeof (lastTry) != "undefined") {
                return lastTry;
        } else {
                return null;
        }
}

BFilter.prototype.filter = function (document, find) {

        this.results('',1);
        this.hits = 0;

        if (find.length < this.min_len) {
                this.show_status();
                return;
        }

        this.debug("filter: '"+find+"'<br>");

        var find_lc = find.toLowerCase();

        var part = find_lc.substr(0,this.min_len);

        // no part found
        if (! this.arr[part]) {
                this.show_status(" for <em>"+find+"</em><br>");
                this.debug("no part "+part);
                return;
        }

        // start anim icon
        //results("<img  src=\"pie.gif\">&nbsp;Please wait, filtering...\n",1);

        // full part? (optimization)
        if (find.length == this.min_len) {
                var html = '';
                for (var i = 0; i < this.arr[part].length; i++) {
                        html += this.html_pre +
                                this.arr[part][i][0] +
                                this.html_mid +
                                (this.hits % 2 == 0 ? '<span style="background: #e0e0e0">' : '');
                        if (this.debug()) { html += i+": "; }
                        html += this.arr[part][i][1] + 
                                (this.hits % 2 == 0 ? '</span>' : '') +
                                this.html_post + "\n";
                        this.hits++;
                }
                this.results(html);
        } else {

                var from = this.binarySearch(this.arr[part], find_lc);

                if (from != null) {
                
                        this.debug("loop "+from+" ... "+this.arr[part].length)+"<br>\n";

                        var html = '';

                        for(var i = from ; i < this.arr[part].length ; i++) {
                                if (this.arr[part][i][1].substring(0,find.length).toLowerCase() != find_lc) {
                                        this.debug("loop exit at "+i);
                                        break;
                                }
                                html += this.html_pre +
                                        this.arr[part][i][0] +
                                        this.html_mid +
                                        (this.hits % 2 == 0 ? '<span style="background: #e0e0e0">' : '');
                                if (this.debug()) { html += i+": "; }
                                html += this.arr[part][i][1] +
                                        (this.hits % 2 == 0 ? '</span>' : '') +
                                        this.html_post + "\n";
                                this.hits++;
                        }

                        this.results(html);
                }

        }

        this.show_status(" for <em>"+find+"</em>");

}


1	/*
2	Fast filtering function using pre-sorted list elements
3	Dobrica Pavlinusic, dpavlin@rot13.org 2004-09-06
4	Matko Andjelinic, matko.andjelinic@gmail.com 2004-09-09 (contributed OO implementation)
5	*/
6
7
8	function BFilter(arr) {
9	this.id_cache = Array();
10	// total number of hits
11	this.hits = 0;
12	this.html_pre = '<a href="';
13	this.html_mid = '">';
14	this.html_post = '</a><br/>';
15	this.html_full_pre = '';
16	this.html_full_post = '';
17
18	if (! arr) {
19	this.debug("ERROR: can't search empty array");
20	return;
21	}
22
23	this.arr = arr;
24	this.debug("index has "+this.arr.length+" parts");
25
26	if (! arr.min_len) {
27	this.results("ERROR: index structure problem");
28	return;
29	} else {
30	this.min_len = arr.min_len;
31	}
32
33	this.debug("index part has "+this.min_len+" parts");
34
35	this.show_status();
36
37	}
38
39	BFilter.prototype.element_id = function (id,no_alert) {
40	if (this.id_cache[id]) {
41	return this.id_cache[id];
42	} else {
43	var el = document.getElementById(id);
44	if (el) {
45	this.id_cache[id] = el;
46	return el;
47	} else {
48	if (! no_alert) {
49	alert("can't find element id: "+id);
50	} else {
51	// don't look it up again
52	this.id_cache[id] = null;
53	}
54	}
55	}
56	}
57
58
59	BFilter.prototype.show_status = function (status) {
60	var html;
61	if (this.hits > 0) {
62	html = "shown "+this.hits+" entries";
63	} else {
64	html = "no results";
65	}
66	if (! status) {
67	html = "Enter "+this.min_len+" letter"+(this.min_len == 1 ? '' : 's')+" to filter entries";
68	status = "";
69	}
70
71	var el = this.element_id("status");
72	el.innerHTML = html+status+"\n";
73	}
74
75	BFilter.prototype.results = function (html,clean) {
76
77	if (! html) { html = ""; }
78
79	// results_div.style.cursor = 'wait'; // 'auto'
80	var results_div = this.element_id("results");
81	if (clean) {
82	results_div.innerHTML = html + "\n";
83	} else {
84	results_div.innerHTML += this.html_full_pre + html +"\n" + this.html_full_post;
85	}
86	}
87
88
89	BFilter.prototype.debug = function (html) {
90
91	//return;
92
93	// check if debugging is on
94	if (! html) { return 1; }
95
96	var debug_div = this.element_id("debug",1);
97	if (! debug_div) { return; }
98
99	if (debug_div.innerHTML) {
100	debug_div.innerHTML =+ html + "x<br>\n";
101	} else {
102	debug_div.innerHTML = html + "y<br>\n";
103	}
104	}
105
106
107	// modified binary search to find first element with substring
108	BFilter.prototype.binarySearch = function (arr, find) {
109	if (!arr \|\| typeof (find) == "undefined" \|\| !arr.length) {
110	return null;
111	}
112	var low = 0;
113	var high = arr.length - 1;
114	var middlearr = parseInt(arr.length / 2);
115	var lastTry;
116	while (low <= high) {
117	var mid = (low + high) / 2;
118	var aTry = (mid < 1) ? 0 : parseInt(mid);
119
120	var curr = arr[aTry][1].substr(0,find.length).toLowerCase();
121	this.debug("low="+low+" high="+high+" lastTry="+lastTry+" "+aTry+": "+curr+"<br>");
122	if (curr < find) {
123	low = aTry + 1;
124	continue;
125	}
126	if (curr > find) {
127	high = aTry - 1;
128	continue;
129	}
130	if (curr == find) {
131	high = aTry - 1;
132	lastTry = aTry;
133	continue;
134	}
135	return aTry;
136	}
137	this.debug("lastTry="+lastTry+"<br>");
138
139	if (typeof (lastTry) != "undefined") {
140	return lastTry;
141	} else {
142	return null;
143	}
144	}
145
146	BFilter.prototype.filter = function (document, find) {
147
148	this.results('',1);
149	this.hits = 0;
150
151	if (find.length < this.min_len) {
152	this.show_status();
153	return;
154	}
155
156	this.debug("filter: '"+find+"'<br>");
157
158	var find_lc = find.toLowerCase();
159
160	var part = find_lc.substr(0,this.min_len);
161
162	// no part found
163	if (! this.arr[part]) {
164	this.show_status(" for <em>"+find+"</em><br>");
165	this.debug("no part "+part);
166	return;
167	}
168
169	// start anim icon
170	//results("<img src=\"pie.gif\"> Please wait, filtering...\n",1);
171
172	// full part? (optimization)
173	if (find.length == this.min_len) {
174	var html = '';
175	for (var i = 0; i < this.arr[part].length; i++) {
176	html += this.html_pre +
177	this.arr[part][i][0] +
178	this.html_mid +
179	(this.hits % 2 == 0 ? '<span style="background: #e0e0e0">' : '');
180	if (this.debug()) { html += i+": "; }
181	html += this.arr[part][i][1] +
182	(this.hits % 2 == 0 ? '</span>' : '') +
183	this.html_post + "\n";
184	this.hits++;
185	}
186	this.results(html);
187	} else {
188
189	var from = this.binarySearch(this.arr[part], find_lc);
190
191	if (from != null) {
192
193	this.debug("loop "+from+" ... "+this.arr[part].length)+"<br>\n";
194
195	var html = '';
196
197	for(var i = from ; i < this.arr[part].length ; i++) {
198	if (this.arr[part][i][1].substring(0,find.length).toLowerCase() != find_lc) {
199	this.debug("loop exit at "+i);
200	break;
201	}
202	html += this.html_pre +
203	this.arr[part][i][0] +
204	this.html_mid +
205	(this.hits % 2 == 0 ? '<span style="background: #e0e0e0">' : '');
206	if (this.debug()) { html += i+": "; }
207	html += this.arr[part][i][1] +
208	(this.hits % 2 == 0 ? '</span>' : '') +
209	this.html_post + "\n";
210	this.hits++;
211	}
212
213	this.results(html);
214	}
215
216	}
217
218	this.show_status(" for <em>"+find+"</em>");
219
220	}
221
222