Class: PackedModel::Base

Inherits:
Object
  • Object
show all
Defined in:
lib/packed_model/base.rb

Constant Summary collapse

@@valid_true_boolean_values = 
nil

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(values = nil) ⇒ Base

Returns a new instance of Base.



205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
 
# File 'lib/packed_model/base.rb', line 205

def initialize(values=nil)
  case values
  when String
    raise InvalidDataException.new("fixed width model expected #{self.bytesize} but got #{values.bytesize}") if self.fixed_width? && self.bytesize != values.bytesize
    self.unpack values
  when Hash
    @changed = true
    @values = []
    values.each do |k, v|
      send("#{k}=", v) if self.class.field_options(k)
    end
    fields.each do |options|
      next unless options[:fields]
      options[:fields].each do |field|
        send("#{field}=", values[field]) if values.has_key?(field)
      end
    end
    # set default values
    fields.each_with_index do |field, idx|
      @values[idx] ||= self.class.default_values[idx]
    end
  when NilClass
    @changed = true
    @values = self.class.default_values.dup
  else
    raise InvalidDataException.new("invalid values")
  end
end

Class Method Details

.add_unpack_callback(callback) ⇒ Object 



269
270
271
272
 
# File 'lib/packed_model/base.rb', line 269

def self.add_unpack_callback(callback)
  @unpack_callbacks ||= []
  @unpack_callbacks << callback
end

.all_field_options ⇒ Object 



15
16
17
 
# File 'lib/packed_model/base.rb', line 15

def self.all_field_options
  {}
end

.attribute(name, options = {}, &block) ⇒ Object 



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
 
# File 'lib/packed_model/base.rb', line 39

def self.attribute(name, options={}, &block)
  options[:name] = name.to_sym
  raise "duplicate field name #{name}" if self.keys.include?(options[:name])
  options[:index] = self.fields.size
  options[:type] ||= :string
  case options[:type]
  when :string
    options[:strip] = true
    options[:null] = true
    options[:pack_directive] = 'Z*'
  when :integer, :int
    options[:default] ||= 0 # pack 'N' directive requires a value for an integer
    options[:bytesize] = 4
    options[:pack_directive] = 'N' # network byte order
  when :char
    options[:size] ||= 1
    options[:bytesize] = options[:size]
    options[:pack_directive] = "a#{options[:size]}"
  when :marker
    raise "missing value for marker" unless options[:value]
    options[:default] = options[:value]
    options[:bytesize] = 4
    options[:pack_directive] = 'N' # network byte order
    options[:unpack_callback] ||= create_marker_unpack_callback(options[:index], options[:value])
  when :custom
    raise "missing pack_directive for #{name}" unless options[:pack_directive]
  else
    raise "Unknown type #{options[:type]}"
  end

  add_unpack_callback(options[:unpack_callback]) if options[:unpack_callback].is_a?(Proc)
  add_unpack_callback(create_strip_unpack_callback(options[:index], options[:null])) if options[:strip]

  class_eval do
    attrs = self.fields << options
    ks = self.keys << options[:name]
    defaults = self.default_values << options[:default]
    ps = self.pack_string << options[:pack_directive]
    kopts = self.all_field_options.merge name.to_sym => options

    class << self; self end.send(:define_method, "fields") do
      attrs
    end
    class << self; self end.send(:define_method, "keys") do
      ks
    end
    class << self; self end.send(:define_method, "default_values") do
      defaults
    end
    class << self; self end.send(:define_method, "pack_string") do
      ps
    end
    class << self; self end.send(:define_method, "all_field_options") do
      kopts
    end

    if self.fixed_width? && options[:bytesize].nil?
      class << self; self end.send(:define_method, "fixed_width?") do
        false
      end
      class << self; self end.send(:define_method, "bytesize") do
        nil
      end
    end

    if self.fixed_width?
      bs = self.bytesize + options[:bytesize]
      class << self; self end.send(:define_method, "bytesize") do
        bs
      end
    end
  end

  method_src = <<-METHOD
    def #{name}
      @values[#{options[:index]}] || #{options[:default].inspect}
    end
    METHOD

  if options.has_key?(:nil)
    method_src << <<-METHOD
      def #{name}_with_nil_check
        #{name}_without_nil_check == #{options[:nil].inspect} ? nil : #{name}_without_nil_check
      end
     alias #{name}_without_nil_check #{name}
     alias #{name} #{name}_with_nil_check
     METHOD
  end

  case options[:type]
  when :string, :char
    method_src << <<-METHOD
    def #{name}=(val)
      val = val.nil? ? nil : val.to_s
      @changed = @changed || @values[#{options[:index]}] != val
      @values[#{options[:index]}] = val
    end
    METHOD
  when :integer, :int
    method_src << <<-METHOD
    def #{name}=(val)
      val = val.to_i
      @changed = @changed || @values[#{options[:index]}] != val
      @values[#{options[:index]}] = val
    end
    METHOD
  when :custom
    if options[:filter].is_a?(Symbol) || options[:filter].is_a?(String)
      method_src << <<-METHOD
      def #{name}=(val)
        val = val.#{options[:filter]}
        @changed = @changed || @values[#{options[:index]}] != val
        @values[#{options[:index]}] = val
      end
      METHOD
    elsif options[:filter] ||= block
      method_src << <<-METHOD
      def #{name}=(val)
        val = self.class.field_options(#{name.inspect})[:filter].call(val)
        @changed = @changed || @values[#{options[:index]}] != val
        @values[#{options[:index]}] = val
      end
      METHOD
    else
      method_src << <<-METHOD
      def #{name}=(val)
        @changed = @changed || @values[#{options[:index]}] != val
        @values[#{options[:index]}] = val
      end
      METHOD
    end
  end

  self.class_eval method_src, __FILE__, __LINE__
end

.bit_vector(name, fields, options = {}) ⇒ Object 



180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
 
# File 'lib/packed_model/base.rb', line 180

def self.bit_vector(name, fields, options={})
  raise "too many fields for bit vecotr #{name}" if fields.size > 32

  self.attribute name, {:type => :integer, :fields => fields}.merge(options)

  name_equals = "#{name}="

  fields.each_with_index do |fld, idx|
    mask = 1 << idx
    neg_mask = 0xFFFFFFFF ^ mask

    define_method fld do
      (self.send(name) & mask) == mask
    end

    define_method "#{fld}=" do |val|
      if self.class.valid_true_boolean_values.include?(val)
        self.send(name_equals, self.send(name) | mask)
      else
        self.send(name_equals, self.send(name) & neg_mask)
      end
    end
  end
end

.field_index(key) ⇒ Object 



23
24
25
 
# File 'lib/packed_model/base.rb', line 23

def self.field_index(key)
  field_options(key)[:index]
end

.field_options(key) ⇒ Object 



19
20
21
 
# File 'lib/packed_model/base.rb', line 19

def self.field_options(key)
  all_field_options[key.to_sym]
end

.fields ⇒ Object 



3
4
5
 
# File 'lib/packed_model/base.rb', line 3

def self.fields
  []
end

.fixed_width? ⇒ Boolean

Returns:

  • (Boolean) 


31
32
33
 
# File 'lib/packed_model/base.rb', line 31

def self.fixed_width?
  true
end

.keys ⇒ Object 



11
12
13
 
# File 'lib/packed_model/base.rb', line 11

def self.keys
  []
end

.unpack_callbacks ⇒ Object 



274
275
276
 
# File 'lib/packed_model/base.rb', line 274

def self.unpack_callbacks
  @unpack_callbacks
end

.valid_true_boolean_values ⇒ Object 



176
177
178
 
# File 'lib/packed_model/base.rb', line 176

def self.valid_true_boolean_values
  @@valid_true_boolean_values ||= [true, 1, '1', 'true', 'on', 'yes']
end

Instance Method Details

#bytesize ⇒ Object 



259
260
261
 
# File 'lib/packed_model/base.rb', line 259

def bytesize
  self.class.fixed_width? ? self.class.bytesize : (@bytesize ||= self.pack.bytesize)
end

#changed! ⇒ Object 



242
243
244
 
# File 'lib/packed_model/base.rb', line 242

def changed!
  @changed = true
end

#changed? ⇒ Boolean

Returns:

  • (Boolean) 


238
239
240
 
# File 'lib/packed_model/base.rb', line 238

def changed?
  !! @changed
end

#fields ⇒ Object 



7
8
9
 
# File 'lib/packed_model/base.rb', line 7

def fields
  self.class.fields
end

#fixed_width? ⇒ Boolean

Returns:

  • (Boolean) 


35
36
37
 
# File 'lib/packed_model/base.rb', line 35

def fixed_width?
  self.class.fixed_width?
end

#keys ⇒ Object 



27
28
29
 
# File 'lib/packed_model/base.rb', line 27

def keys
  self.class.keys
end

#not_changed! ⇒ Object 



246
247
248
 
# File 'lib/packed_model/base.rb', line 246

def not_changed!
  @changed = false
end

#pack ⇒ Object 



255
256
257
 
# File 'lib/packed_model/base.rb', line 255

def pack
  @values.pack self.class.pack_string
end

#size ⇒ Object 



262
263
264
 
# File 'lib/packed_model/base.rb', line 262

def bytesize
  self.class.fixed_width? ? self.class.bytesize : (@bytesize ||= self.pack.bytesize)
end

#to_hash ⇒ Object Also known as: to_h 



250
251
252
 
# File 'lib/packed_model/base.rb', line 250

def to_hash
  Hash[self.keys.zip @values]
end

#unpack(str) ⇒ Object 



264
265
266
267
 
# File 'lib/packed_model/base.rb', line 264

def unpack(str)
  @values = str.unpack(self.class.pack_string)
  self.unpack_callbacks.each { |c| c.call self } if self.unpack_callbacks
end

#unpack_callbacks ⇒ Object 



278
279
280
 
# File 'lib/packed_model/base.rb', line 278

def unpack_callbacks
  self.class.unpack_callbacks
end

#values ⇒ Object 



234
235
236
 
# File 'lib/packed_model/base.rb', line 234

def values
  @values
end