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 |
|