Class: CBOR::Buffer

Inherits:
Object show all
Defined in:
lib/cbor-pure.rb,
lib/cbor-pretty.rb

Constant Summary collapse

HALF_NAN_BYTES = 
("\xf9".force_encoding(Encoding::BINARY) + Half::NAN_BYTES).freeze
MT_TO_ENCODING = 
{2 => Encoding::BINARY, 3 => Encoding::UTF_8}
MT_NAMES = 
["unsigned", "negative", "bytes", "text", "array", "map", "tag", "primitive"]

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(s = String.new) ⇒ Buffer

Returns a new instance of Buffer.



100
101
102
103
 
# File 'lib/cbor-pure.rb', line 100

def initialize(s = String.new)
  @buffer = s
  @pos = 0
end

Instance Attribute Details

#buffer ⇒ Object (readonly)

Returns the value of attribute buffer.



99
100
101
 
# File 'lib/cbor-pure.rb', line 99

def buffer
  @buffer
end

Instance Method Details

#add(d) ⇒ Object 



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
 
# File 'lib/cbor-pure.rb', line 151

def add(d)
  case d
  when Integer
    ib = if d < 0
           d = -1-d
           0x20
         else
           0x00
         end
    head(ib, d) {             # block is called if things do not fit
      s = bignum_to_bytes(d)
      head(0xc0, TAG_BIGNUM_BASE + (ib >> 5))
      head(0x40, s.bytesize)
      s
    }
  when Numeric; addfloat(d)
  when Symbol; add(d.to_s)    # hack: this should really be tagged
  when Simple; head(0xe0, d.value)
  when false; head(0xe0, 20)
  when true; head(0xe0, 21)
  when nil; head(0xe0, 22)
  when Tagged                 # we don't handle :simple here
    head(0xc0, d.tag)
    add(d.value)
  when String
    lengths = d.cbor_stream?
    e = d
    ib = if d.encoding == Encoding::BINARY
           0x40
         else
           d = d.encode(Encoding::UTF_8).force_encoding(Encoding::BINARY)
           0x60
         end
    if lengths
      @buffer << (ib + 31)
      pos = 0
      lengths.each do |r|
        add(e[pos, r])
        pos += r
      end
      @buffer << 0xff
    else
      head(ib, d.bytesize)
      @buffer << d
    end
  when Array
    if d.cbor_stream?
      @buffer << 0x9f
      d.each {|di| add(di)}
      @buffer << 0xff
    else
      head(0x80, d.size)
      d.each {|di| add(di)}
    end
  when Hash
    if d.cbor_stream?
      @buffer << 0xbf
      d.each {|k, v| add(k); add(v)}
      @buffer << 0xff
    else
      head(0xa0, d.size)
      d.each {|k, v| add(k); add(v)}
    end
  else
    raise("Don't know how to encode #{d.inspect}")
  end
  self
end

#addfloat(fv) ⇒ Object 



125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
 
# File 'lib/cbor-pure.rb', line 125

def addfloat(fv)
  if fv.nan?
    @buffer << HALF_NAN_BYTES
  else
    ss = [fv].pack("g")         # single-precision
    if ss.unpack("g").first == fv
      if hs = Half.encode_from_single(fv, ss)
        @buffer << 0xf9 << hs
      else
        @buffer << 0xfa << ss
      end
    else
      @buffer << [0xfb, fv].pack("CG") # double-precision
    end
  end
end

#atleast(n) ⇒ Object

Raises:



220
221
222
223
 
# File 'lib/cbor-pure.rb', line 220

def atleast(n)
  left = @buffer.bytesize - @pos
  raise OutOfBytesError.new(n - left) if n > left
end

#bignum_to_bytes(d) ⇒ Object 



142
143
144
145
146
147
148
149
 
# File 'lib/cbor-pure.rb', line 142

def bignum_to_bytes(d)
  s = String.new
  while (d != 0)
    s << (d & 0xFF)
    d >>= 8
  end
  s.reverse!
end

#decode_item(breakable = false) ⇒ Object 



264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
 
# File 'lib/cbor-pure.rb', line 264

def decode_item(breakable = false)
  ib = take(1).ord
  ai = ib & 0x1F
  val = case ai
        when 0...24; ai
        when 24; take(1).ord
        when 25; take(2).unpack("n").first
        when 26; (s = take(4)).unpack("N").first
        when 27; (s = take(8)).unpack("Q>").first
        when 31; return decode_item_streaming(ib, breakable)
        else raise "unknown additional information #{ai} in ib #{ib}"
        end
  case ib >>= 5
  when 0; val
  when 1; -1-val
  when 7
    case ai
    when 20; false
    when 21; true
    when 22; nil
    # when 23; Simple.new(23)   # Ruby does not have Undefined
    when 24;
      raise "two-byte simple is #{val} but must be between 32 and 255" unless val >= 32;
      Simple.new(val)
    when 25; Half.decode(val)
    when 26; s.unpack("g").first # cannot go directly from val
    when 27; s.unpack("G").first #   in Ruby
    else
      Simple.new(val)
    end
  when 6
    di = decode_item
    if String === di && (val & ~1) == TAG_BIGNUM_BASE
      (TAG_BIGNUM_BASE - val) ^ di.bytes.inject(0) {|sum, b| sum <<= 8; sum += b }
    else
      Tagged.new(val, di)
    end
  when 2; take(val).force_encoding(Encoding::BINARY)
  when 3; take(val).force_encoding(Encoding::UTF_8)
  when 4; atleast(val); Array.new(val) { decode_item }
  when 5; atleast(val<<1); Hash[Array.new(val) {[decode_item, decode_item]}]
  end
end

#decode_item_final ⇒ Object 



308
309
310
311
312
 
# File 'lib/cbor-pure.rb', line 308

def decode_item_final
  val = decode_item
  raise "extra bytes follow after a deserialized object of #@pos bytes" if @pos != @buffer.size
  val
end

#decode_item_streaming(ib, breakable) ⇒ Object 



234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
 
# File 'lib/cbor-pure.rb', line 234

def decode_item_streaming(ib, breakable)
  case ib >>= 5
  when 2, 3
    want_encoding = MT_TO_ENCODING[ib]
    subs = []
    while (element = decode_item(true)) != BREAK
      raise "non-string (#{element.inspect}) in streaming string" unless String === element
      raise "bytes/text mismatch (#{element.encoding} != #{want_encoding}) in streaming string" unless element.encoding == want_encoding
      subs << element
    end
    result = subs.join.cbor_stream!(subs.map(&:length)).force_encoding(want_encoding)
  when 4
    result = Array.new;
    while (element = decode_item(true)) != BREAK
      result << element
    end
    result
  when 5
    result = Hash.new
    while (key = decode_item(true)) != BREAK
      result[key] = decode_item
    end
    result
  when 7
    raise "break stop code outside indefinite length item" unless breakable
    BREAK
  else raise "unknown ib #{ib} for additional information 31"
  end
end

#decode_item_with_rest ⇒ Object 



314
315
316
317
 
# File 'lib/cbor-pure.rb', line 314

def decode_item_with_rest
  val = decode_item
  [val, @buffer[@pos..-1]]
end

#decode_items ⇒ Object 



319
320
321
322
323
324
325
 
# File 'lib/cbor-pure.rb', line 319

def decode_items
  ret = []
  while @pos != buffer.size
    ret << decode_item
  end
  ret
end

#empty? ⇒ Boolean

Returns:

  • (Boolean) 


327
328
329
 
# File 'lib/cbor-pure.rb', line 327

def empty?
  @pos == buffer.size
end

#head(ib, n) ⇒ Object 



105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
 
# File 'lib/cbor-pure.rb', line 105

def head(ib, n)
  @buffer <<
    case n
    when 0...24
      [ib + n].pack("C")
    when 0...256
      [ib + 24, n].pack("CC")
    when 0...65536
      [ib + 25, n].pack("Cn")
    when 0...4294967296
      [ib + 26, n].pack("CN")
    when 0...18446744073709551616
      [ib + 27, n].pack("CQ>")
    else
      yield                   # throw back to caller
    end
end

#pretty_item ⇒ Object 



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
 
# File 'lib/cbor-pretty.rb', line 59

def pretty_item
  ib = take_and_print(1, '   ' * @indent).ord
  ai = ib & 0x1F
  val = case ai
        when 0...24; ai
        when 24; take_and_print(1, ' ').ord
        when 25; take_and_print(2, ' ').unpack("n").first
        when 26; (s = take_and_print(4, ' ')).unpack("N").first
        when 27; (s = take_and_print(8, ' ')).unpack("Q>").first
        when 31; return pretty_item_streaming(ib)
        else raise "unknown additional information #{ai} in ib #{ib}"
        end
  @out << " # #{MT_NAMES[ib >> 5]}(#{val})\n"
  @indent += 1
  case ib >>= 5
  when 6
    pretty_item
  when 2, 3
    @out << '   ' * (@indent)
    s = take_and_print(val)
    @out << " # #{s.force_encoding(Encoding::UTF_8).to_json rescue s.inspect}"
    @out << "\n"
  when 4; val.times { pretty_item }
  when 5; val.times { pretty_item; pretty_item}
  end
  @indent -= 1
  nil
end

#pretty_item_final(indent = 0, max_target = 40, seq = false) ⇒ Object 



88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
 
# File 'lib/cbor-pretty.rb', line 88

def pretty_item_final(indent = 0, max_target = 40, seq = false)
  @out = ''
  @indent = indent
  pretty_item
  unless seq
    raise if @pos != @buffer.size
  end
  target = [@out.each_line.map {|ln| ln =~ /#/ || 0}.max, max_target].min
  @out.each_line.map {|ln|
    col = ln =~ /#/
    if col && col < target
      ln[col, 0] = ' ' * (target - col)
    end
    ln
  }.join
end

#pretty_item_streaming(ib) ⇒ Object 



42
43
44
45
46
47
48
49
50
51
52
53
54
55
 
# File 'lib/cbor-pretty.rb', line 42

def pretty_item_streaming(ib)
  res = nil
  @out << " # #{MT_NAMES[ib >> 5]}(*)\n"
  @indent += 1
  case ib >>= 5
  when 2, 3, 4, 5
    while (element = pretty_item) != BREAK
    end
  when 7; res = BREAK
  else raise "unknown ib #{ib} for additional information 31"
  end
  @indent -= 1
  res
end

#take(n) ⇒ Object

Raises:



225
226
227
228
229
230
 
# File 'lib/cbor-pure.rb', line 225

def take(n)
  opos = @pos
  @pos += n
  raise OutOfBytesError.new(@pos - @buffer.bytesize) if @pos > @buffer.bytesize
  @buffer[opos, n]
end

#take_and_print(n, prefix = '') ⇒ Object 



35
36
37
38
39
40
 
# File 'lib/cbor-pretty.rb', line 35

def take_and_print(n, prefix = '')
  s = take(n)
  @out << prefix
  @out << s.hexbytes
  s
end