Class: AMQP::Buffer

Inherits:
Object
  • Object
show all
Defined in:
lib/amqp/buffer.rb

Overview

:nodoc: all

Defined Under Namespace

Classes: InvalidType, Overflow

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(data = '') ⇒ Buffer

Returns a new instance of Buffer.



16
17
18
19
# File 'lib/amqp/buffer.rb', line 16

def initialize data = ''
  @data = data
  @pos = 0
end

Instance Attribute Details

#posObject (readonly)

Returns the value of attribute pos.



21
22
23
# File 'lib/amqp/buffer.rb', line 21

def pos
  @pos
end

Instance Method Details

#<<(data) ⇒ Object



29
30
31
32
# File 'lib/amqp/buffer.rb', line 29

def << data
  @data << data.to_s
  self
end

#_read(size, pack = nil) ⇒ Object



250
251
252
253
254
255
256
257
258
259
260
261
262
# File 'lib/amqp/buffer.rb', line 250

def _read size, pack = nil
  if @pos + size > length
    raise Overflow
  else
    data = @data[@pos,size]
    @data[@pos,size] = ''
    if pack
      data = data.unpack(pack)
      data = data.pop if data.size == 1
    end
    data
  end
end

#_write(data, pack = nil) ⇒ Object



264
265
266
267
268
# File 'lib/amqp/buffer.rb', line 264

def _write data, pack = nil
  data = [*data].pack(pack) if pack
  @data[@pos,0] = data
  @pos += data.bytesize
end

#dataObject Also known as: contents, to_s



23
24
25
# File 'lib/amqp/buffer.rb', line 23

def data
  @data.clone
end

#empty?Boolean

Returns:

  • (Boolean)


38
39
40
# File 'lib/amqp/buffer.rb', line 38

def empty?
  pos == length
end

#extractObject



240
241
242
243
244
245
246
247
248
# File 'lib/amqp/buffer.rb', line 240

def extract
  begin
    cur_data, cur_pos = @data.clone, @pos
    yield self
  rescue Overflow
    @data, @pos = cur_data, cur_pos
    nil
  end
end

#lengthObject



34
35
36
# File 'lib/amqp/buffer.rb', line 34

def length
  @data.bytesize
end

#read(*types) ⇒ Object



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
# File 'lib/amqp/buffer.rb', line 83

def read *types
  if types.first == :properties
    return read_properties(*types)
  end

  values = types.map do |type|
    case type
    when :octet
      _read(1, 'C')
    when :short
      _read(2, 'n')
    when :long
      _read(4, 'N')
    when :longlong
      upper, lower = _read(8, 'NN')
      upper << 32 | lower
    when :shortstr
      _read read(:octet)
    when :longstr
      _read read(:long)
    when :timestamp
      Time.at read(:longlong)
    when :table
      t = Hash.new

      table = Buffer.new(read(:longstr))
      until table.empty?
        key, type = table.read(:shortstr, :octet)
        key = key.intern
        t[key] ||= case type
                   when 83 # 'S'
                     table.read(:longstr)
                   when 73 # 'I'
                     table.read(:long)
                   when 68 # 'D'
                     exp = table.read(:octet)
                     num = table.read(:long)
                     num / 10.0**exp
                   when 84 # 'T'
                     table.read(:timestamp)
                   when 70 # 'F'
                     table.read(:table)
                   end
      end

      t
    when :bit
      if (@bits ||= []).empty?
        val = read(:octet)
        @bits = (0..7).map{|i| (val & 1<<i) != 0 }
      end

      @bits.shift
    else
      raise InvalidType, "Cannot read data of type #{type}"
    end
  end
  
  types.size == 1 ? values.first : values
end

#read_properties(*types) ⇒ Object



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
# File 'lib/amqp/buffer.rb', line 46

def read_properties *types
  types.shift if types.first == :properties
  
  i = 0
  values = []

  while props = read(:short)
    (0..14).each do |n|
      # no more property types
      break unless types[i]
      
      # if flag is set
      if props & (1<<(15-n)) != 0
        if types[i] == :bit
          # bit values exist in flags only
          values << true
        else
          # save type name for later reading
          values << types[i]
        end
      else
        # property not set or is false bit
        values << (types[i] == :bit ? false : nil)
      end

      i+=1
    end

    # bit(0) == 0 means no more property flags
    break unless props & 1 == 1
  end

  values.map do |value|
    value.is_a?(Symbol) ? read(value) : value
  end
end

#rewindObject



42
43
44
# File 'lib/amqp/buffer.rb', line 42

def rewind
  @pos = 0
end

#write(type, data) ⇒ Object



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
200
201
202
203
204
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
233
234
235
236
237
238
# File 'lib/amqp/buffer.rb', line 144

def write type, data
  case type
  when :octet
    _write(data, 'C')
  when :short
    _write(data, 'n')
  when :long
    _write(data, 'N')
  when :longlong
    lower =  data & 0xffffffff
    upper = (data & ~0xffffffff) >> 32
    _write([upper, lower], 'NN')
  when :shortstr
    data = (data || '').to_s
    _write([data.bytesize, data], 'Ca*')
  when :longstr
    if data.is_a? Hash
      write(:table, data)
    else
      data = (data || '').to_s
      _write([data.bytesize, data], 'Na*')
    end
  when :timestamp
    write(:longlong, data.to_i)
  when :table
    data ||= {}
    write :longstr, (data.inject(Buffer.new) do |table, (key, value)|
                      table.write(:shortstr, key.to_s)

                      case value
                      when String
                        table.write(:octet, 83) # 'S'
                        table.write(:longstr, value.to_s)
                      when Fixnum
                        table.write(:octet, 73) # 'I'
                        table.write(:long, value)
                      when Float
                        table.write(:octet, 68) # 'D'
                        # XXX there's gotta be a better way to do this..
                        exp = value.to_s.split('.').last.bytesize
                        num = value * 10**exp
                        table.write(:octet, exp)
                        table.write(:long, num)
                      when Time
                        table.write(:octet, 84) # 'T'
                        table.write(:timestamp, value)
                      when Hash
                        table.write(:octet, 70) # 'F'
                        table.write(:table, value)
                      end

                      table
                    end)
  when :bit
    [*data].to_enum(:each_slice, 8).each{|bits|
      write(:octet, bits.enum_with_index.inject(0){ |byte, (bit, i)|
        byte |= 1<<i if bit
        byte
       })
     }
  when :properties
    values = []
    data.enum_with_index.inject(0) do |short, ((type, value), i)|
      n = i % 15
      last = i+1 == data.size

      if (n == 0 and i != 0) or last
        if data.size > i+1
          short |= 1<<0
        elsif last and value
          values << [type,value]
          short |= 1<<(15-n)
        end

        write(:short, short)
        short = 0
      end

      if value and !last
        values << [type,value] 
        short |= 1<<(15-n)
      end

      short
    end
    
    values.each do |type, value|
      write(type, value) unless type == :bit
    end
  else
    raise InvalidType, "Cannot write data of type #{type}"
  end
  
  self
end