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
|
/* <copyright>
This file contains proprietary software owned by Motorola Mobility, Inc.<br/>
No rights, expressed or implied, whatsoever to this software are provided by Motorola Mobility, Inc. hereunder.<br/>
(c) Copyright 2011 Motorola Mobility, Inc. All Rights Reserved.
</copyright> */
/**
Defines the BitField class, that compactly stores multiple values as a short series of bits.
@module montage/core/bitfield
@requires montage/core/core
*/
var Montage = require("montage").Montage;
/**
The BitField object compactly stores multiple values as a short series of bits. This implementation is limited to 32 fields.
@class module:montage/core/bitfield.BitField
@classdesc Compactly stores multiple values as a short series of bits.
@extends module:montage/core/core.Montage
*/
var BitField = exports.BitField = Montage.create(Montage, /** @lends module:montage/core/bitfield.BitField# */ {
/**
Creates a new BitField object containing the fields provided in the propertyDescriptor parameter.
@function
@param {Object} propertyDescriptor An object containing one or more property name/value pairs. Each pair is added to the new BitField.
@returns {Object} A new BitField object that contains fields described by the property descriptor.
@example var bitField = BitField.create();
bitField = BitField.create().initWithDescriptor({
likes_golf: {
value: false
},
likes_basketball: {
value: true
},
likes_baseball: {
value: false
},
});
*/
initWithDescriptor: {
enumerable: false,
value: function(propertyDescriptor) {
var fieldName;
this.reset();
for (fieldName in propertyDescriptor) {
this.addField(fieldName, propertyDescriptor[fieldName].value);
}
return this;
}
},
/**
Adds a new field to a BitField instance.
@function
@param {String} aFieldName The name of the field to add.
@param {Mixed} defaultValue The new field's default value.
*/
addField: {
enumerable: false,
value: function(aFieldName, defaultValue) {
if (aFieldName in this) {
return;
}
if (this._fieldCount >= 32) {
throw "BitField 32 fields limit reached.";
}
//We try to recycle slots as limited to 32bits
this._trueValue += (this._fields[aFieldName] = this._constantsToReuse.length ? this._constantsToReuse.shift() : (1 << this._fieldCount));
Montage.defineProperty(this, aFieldName, {
enumerable: true,
get: function() {
return (this._value === this._trueValue);
},
set: function(value) {
value ? (this._value |= this._fields[aFieldName]) : (this._value &= ~ (this._fields[aFieldName]));
if (this.value) {
this.callDelegateMethod();
}
}
});
this._fieldCount++;
if (!! defaultValue) {
this[aFieldName] = true;
}
}
},
/**
@private
*/
_constantsToReuse: {
enumerable: false,
value: []
},
/**
Removes a field from the bitfield.
@function
@param {String} aFieldName The name of the field to remove.
*/
removeField: {
enumerable: false,
value: function(aFieldName) {
delete this[aFieldName];
this._constantsToReuse.push(this._fields[aFieldName]);
this._trueValue -= this._fields[aFieldName];
delete this._fields[aFieldName];
}
},
/**
The BitField object's delegate.
@type {Property}
@default null
*/
delegate: {
enumerable: false,
value: null
},
/**
@function
@returns Nothing
*/
callDelegateMethod: {
value: function() {
var delegateMethod;
if (this.delegate && typeof (delegateMethod = this.delegate.bitFieldDidBecomeTrue) === "function") {
delegateMethod.call(this.delegate, this);
}
},
enumerable: false
},
/**
@type {Function}
@default {Number} 0
*/
value: {
enumerable: false,
get: function() {
return (this._value === this._trueValue);
}
},
/**
@private
*/
_fieldCount: {
enumerable: false,
value: 0
},
/**
@private
*/
_value: {
enumerable: false,
value: 0
},
/**
@private
*/
_trueValue: {
enumerable: false,
value: 0
},
/**
@function
*/
reset: {
enumerable: false,
value: function() {
this._value = 0x0;
}
},
/**
@private
*/
_fields: {
enumerable: false,
value: {}
},
/**
@function
@returns result
*/
toString: {
value: function() {
var fieldNames = this._fields,
i,
iField,
result = "";
for (i = 0; (iField = fieldNames[i]); i++) {
result += iField + "[" + (this._value & fieldNames[iField]) + "], ";
}
return result;
}
}
});
|