Class: Philiprehberger::BitField::Base

Inherits:
Object
  • Object
show all
Includes:
Comparable
Defined in:
lib/philiprehberger/bit_field.rb

Overview

Named bit flags with symbolic access, set operations, and serialization

Examples:

class Permissions < Philiprehberger::BitField::Base
  flag :read, 0
  flag :write, 1
  flag :execute, 2
  group :read_write, [:read, :write]
end
perms = Permissions.new(:read, :write)
perms.read?    # => true
perms.execute? # => false

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(*initial_flags) ⇒ Base

Create a new bit field with the given flags set

Parameters:

  • initial_flags (Array<Symbol>) —

    flags to set initially



139
140
141
142
 
# File 'lib/philiprehberger/bit_field.rb', line 139

def initialize(*initial_flags)
  @value = 0
  initial_flags.each { |f| set(f) }
end

Class Method Details

.flag(name, position) ⇒ void

This method returns an undefined value.

Define a named flag at the given bit position

Parameters:

  • name (Symbol) —

    the flag name

  • position (Integer) —

    the bit position (0-based)

Raises:



31
32
33
34
35
36
37
38
39
40
41
 
# File 'lib/philiprehberger/bit_field.rb', line 31

def flag(name, position)
  raise Error, 'position must be a non-negative integer' unless position.is_a?(Integer) && position >= 0
  raise Error, "flag #{name} already defined" if flags_map.key?(name)
  raise Error, "position #{position} already used" if flags_map.any? { |_, p| p == position }

  flags_map[name] = position

  define_method(:"#{name}?") do
    flag_set?(name)
  end
end

.flags ⇒ Array<Symbol>

Return all defined flag names

Returns:

  • (Array<Symbol>) 


61
62
63
 
# File 'lib/philiprehberger/bit_field.rb', line 61

def flags
  flags_map.keys
end

.flags_map ⇒ Object

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future. 



118
119
120
 
# File 'lib/philiprehberger/bit_field.rb', line 118

def flags_map
  @flags_map ||= {}
end

.from_h(hash) ⇒ Base

Create an instance from a hash

Parameters:

  • hash (Hash) —

    hash with :flags/:value or “flags”/“value” keys

Returns:

Raises:



110
111
112
113
114
115
 
# File 'lib/philiprehberger/bit_field.rb', line 110

def from_h(hash)
  value = hash[:value] || hash['value']
  raise Error, 'hash must include a value key' if value.nil?

  from_i(value)
end

.from_i(value) ⇒ Base

Create an instance from an integer value

Parameters:

  • value (Integer) —

    the integer representation

Returns:

Raises:



89
90
91
92
93
94
95
 
# File 'lib/philiprehberger/bit_field.rb', line 89

def from_i(value)
  raise Error, 'value must be a non-negative integer' unless value.is_a?(Integer) && value >= 0

  instance = new
  instance.instance_variable_set(:@value, value)
  instance
end

.from_json(json_string) ⇒ Base

Create an instance from a JSON string

Parameters:

  • json_string (String) —

    JSON with “flags” and “value” keys

Returns:



101
102
103
104
 
# File 'lib/philiprehberger/bit_field.rb', line 101

def from_json(json_string)
  data = JSON.parse(json_string)
  from_h(data)
end

.group(name, flag_names) ⇒ void

This method returns an undefined value.

Define a named group of flags

Parameters:

  • name (Symbol) —

    the group name

  • flag_names (Array<Symbol>) —

    the flags in this group

Raises:



48
49
50
51
52
53
54
55
56
 
# File 'lib/philiprehberger/bit_field.rb', line 48

def group(name, flag_names)
  raise Error, "group #{name} already defined" if groups_map.key?(name)

  flag_names.each do |f|
    raise Error, "unknown flag #{f} in group #{name}" unless flags_map.key?(f)
  end

  groups_map[name] = flag_names.dup.freeze
end

.groups ⇒ Hash{Symbol => Array<Symbol>}

Return all defined group definitions

Returns:

  • (Hash{Symbol => Array<Symbol>}) 


68
69
70
 
# File 'lib/philiprehberger/bit_field.rb', line 68

def groups
  groups_map.dup
end

.groups_map ⇒ Object

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future. 



123
124
125
 
# File 'lib/philiprehberger/bit_field.rb', line 123

def groups_map
  @groups_map ||= {}
end

.inherited(subclass) ⇒ Object

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future. 



128
129
130
131
132
 
# File 'lib/philiprehberger/bit_field.rb', line 128

def inherited(subclass)
  super
  subclass.instance_variable_set(:@flags_map, flags_map.dup)
  subclass.instance_variable_set(:@groups_map, groups_map.dup)
end

.strict(*initial_flags) ⇒ Base

Create an instance that raises on unknown flag names

Parameters:

  • initial_flags (Array<Symbol>) —

    flags to set initially

Returns:

Raises:

  • (Error) —

    if any flag name is not defined



77
78
79
80
81
82
83
 
# File 'lib/philiprehberger/bit_field.rb', line 77

def strict(*initial_flags)
  initial_flags.each do |f|
    raise Error, "unknown flag: #{f}" unless flags_map.key?(f)
  end

  new(*initial_flags)
end

Instance Method Details

#&(other) ⇒ Base

Bitwise AND

Parameters:

  • other (Base) —

    another bit field of the same type

Returns:

Raises:



316
317
318
319
320
 
# File 'lib/philiprehberger/bit_field.rb', line 316

def &(other)
  raise Error, 'cannot combine different bit field types' unless other.is_a?(self.class)

  self.class.from_i(@value & other.to_i)
end

#<=>(other) ⇒ Integer?

Compare by integer value

Parameters:

  • other (Base) —

    another bit field

Returns:

  • (Integer, nil) 


336
337
338
339
340
 
# File 'lib/philiprehberger/bit_field.rb', line 336

def <=>(other)
  return nil unless other.is_a?(self.class)

  @value <=> other.to_i
end

#==(other) ⇒ Boolean Also known as: eql?

Equality check

Parameters:

  • other (Base) —

    another bit field

Returns:

  • (Boolean) 


346
347
348
 
# File 'lib/philiprehberger/bit_field.rb', line 346

def ==(other)
  other.is_a?(self.class) && @value == other.to_i
end

#^(other) ⇒ Base

Bitwise XOR

Parameters:

  • other (Base) —

    another bit field of the same type

Returns:

Raises:



326
327
328
329
330
 
# File 'lib/philiprehberger/bit_field.rb', line 326

def ^(other)
  raise Error, 'cannot combine different bit field types' unless other.is_a?(self.class)

  self.class.from_i(@value ^ other.to_i)
end

#added_flags(other) ⇒ Array<Symbol>

Return flags set in self but not in other

Parameters:

  • other (Base) —

    another bit field of the same type

Returns:

  • (Array<Symbol>)

Raises:



361
362
363
364
365
 
# File 'lib/philiprehberger/bit_field.rb', line 361

def added_flags(other)
  raise Error, 'cannot compare different bit field types' unless other.is_a?(self.class)

  self.class.flags.select { |f| flag_set?(f) && !other.flag_set?(f) }
end

#clear(flag) ⇒ self

Clear a flag

Parameters:

  • flag (Symbol) —

    the flag name

Returns:

  • (self) 


175
176
177
178
179
 
# File 'lib/philiprehberger/bit_field.rb', line 175

def clear(flag)
  pos = position_for(flag)
  @value &= ~(1 << pos)
  self
end

#clear_all ⇒ self

Clear all defined flags

Returns:

  • (self) 


202
203
204
205
 
# File 'lib/philiprehberger/bit_field.rb', line 202

def clear_all
  @value = 0
  self
end

#clear_flags(*flag_names) ⇒ self

Clear multiple specific flags at once

Parameters:

  • flag_names (Array<Symbol>) —

    flags to clear

Returns:

  • (self) 


220
221
222
223
 
# File 'lib/philiprehberger/bit_field.rb', line 220

def clear_flags(*flag_names)
  flag_names.each { |f| clear(f) }
  self
end

#clear_group(group_name) ⇒ self

Clear all flags in a group

Parameters:

  • group_name (Symbol) —

    the group name

Returns:

  • (self) 


238
239
240
241
 
# File 'lib/philiprehberger/bit_field.rb', line 238

def clear_group(group_name)
  group_flags(group_name).each { |f| clear(f) }
  self
end

#flag_clear?(flag) ⇒ Boolean

Check if a flag is clear (not set)

Parameters:

  • flag (Symbol) —

    the flag name

Returns:

  • (Boolean) 


157
158
159
 
# File 'lib/philiprehberger/bit_field.rb', line 157

def flag_clear?(flag)
  !flag_set?(flag)
end

#flag_set?(flag) ⇒ Boolean

Check if a flag is set

Parameters:

  • flag (Symbol) —

    the flag name

Returns:

  • (Boolean) 


148
149
150
151
 
# File 'lib/philiprehberger/bit_field.rb', line 148

def flag_set?(flag)
  pos = position_for(flag)
  @value.anybits?(1 << pos)
end

#flags ⇒ Array<Symbol>

Return all defined flag names

Returns:

  • (Array<Symbol>) 


284
285
286
 
# File 'lib/philiprehberger/bit_field.rb', line 284

def flags
  self.class.flags
end

#group_any_set?(group_name) ⇒ Boolean

Check if any flag in a group is set

Parameters:

  • group_name (Symbol) —

    the group name

Returns:

  • (Boolean) 


255
256
257
 
# File 'lib/philiprehberger/bit_field.rb', line 255

def group_any_set?(group_name)
  group_flags(group_name).any? { |f| flag_set?(f) }
end

#group_none_set?(group_name) ⇒ Boolean

Check if no flags in a group are set

Parameters:

  • group_name (Symbol) —

    the group name

Returns:

  • (Boolean) 


263
264
265
 
# File 'lib/philiprehberger/bit_field.rb', line 263

def group_none_set?(group_name)
  group_flags(group_name).none? { |f| flag_set?(f) }
end

#group_set?(group_name) ⇒ Boolean

Check if all flags in a group are set

Parameters:

  • group_name (Symbol) —

    the group name

Returns:

  • (Boolean) 


247
248
249
 
# File 'lib/philiprehberger/bit_field.rb', line 247

def group_set?(group_name)
  group_flags(group_name).all? { |f| flag_set?(f) }
end

#hash ⇒ Integer

Hash code for use in Hash keys

Returns:

  • (Integer) 


353
354
355
 
# File 'lib/philiprehberger/bit_field.rb', line 353

def hash
  [self.class, @value].hash
end

#removed_flags(other) ⇒ Array<Symbol>

Return flags set in other but not in self

Parameters:

  • other (Base) —

    another bit field of the same type

Returns:

  • (Array<Symbol>)

Raises:



371
372
373
374
375
 
# File 'lib/philiprehberger/bit_field.rb', line 371

def removed_flags(other)
  raise Error, 'cannot compare different bit field types' unless other.is_a?(self.class)

  self.class.flags.select { |f| !flag_set?(f) && other.flag_set?(f) }
end

#set(flag) ⇒ self

Set a flag

Parameters:

  • flag (Symbol) —

    the flag name

Returns:

  • (self) 


165
166
167
168
169
 
# File 'lib/philiprehberger/bit_field.rb', line 165

def set(flag)
  pos = position_for(flag)
  @value |= (1 << pos)
  self
end

#set_all ⇒ self

Set all defined flags

Returns:

  • (self) 


194
195
196
197
 
# File 'lib/philiprehberger/bit_field.rb', line 194

def set_all
  self.class.flags.each { |f| set(f) }
  self
end

#set_flags(*flag_names) ⇒ self

Set multiple specific flags at once

Parameters:

  • flag_names (Array<Symbol>) —

    flags to set

Returns:

  • (self) 


211
212
213
214
 
# File 'lib/philiprehberger/bit_field.rb', line 211

def set_flags(*flag_names)
  flag_names.each { |f| set(f) }
  self
end

#set_group(group_name) ⇒ self

Set all flags in a group

Parameters:

  • group_name (Symbol) —

    the group name

Returns:

  • (self) 


229
230
231
232
 
# File 'lib/philiprehberger/bit_field.rb', line 229

def set_group(group_name)
  group_flags(group_name).each { |f| set(f) }
  self
end

#to_a ⇒ Array<Symbol>

Return an array of set flag names

Returns:

  • (Array<Symbol>) 


277
278
279
 
# File 'lib/philiprehberger/bit_field.rb', line 277

def to_a
  self.class.flags.select { |f| flag_set?(f) }
end

#to_h ⇒ Hash{Symbol => Object}

Return a hash representation

Returns:

  • (Hash{Symbol => Object}) 


291
292
293
 
# File 'lib/philiprehberger/bit_field.rb', line 291

def to_h
  { flags: to_a, value: @value }
end

#to_i ⇒ Integer

Return the integer representation

Returns:

  • (Integer) 


270
271
272
 
# File 'lib/philiprehberger/bit_field.rb', line 270

def to_i
  @value
end

#to_json(*_args) ⇒ String

Return a JSON string representation

Returns:

  • (String) 


298
299
300
 
# File 'lib/philiprehberger/bit_field.rb', line 298

def to_json(*_args)
  { flags: to_a.map(&:to_s), value: @value }.to_json
end

#toggle(flag) ⇒ self

Toggle a flag

Parameters:

  • flag (Symbol) —

    the flag name

Returns:

  • (self) 


185
186
187
188
189
 
# File 'lib/philiprehberger/bit_field.rb', line 185

def toggle(flag)
  pos = position_for(flag)
  @value ^= (1 << pos)
  self
end

#|(other) ⇒ Base

Bitwise OR

Parameters:

  • other (Base) —

    another bit field of the same type

Returns:

Raises:



306
307
308
309
310
 
# File 'lib/philiprehberger/bit_field.rb', line 306

def |(other)
  raise Error, 'cannot combine different bit field types' unless other.is_a?(self.class)

  self.class.from_i(@value | other.to_i)
end