Class: Antlr4::Runtime::FlexibleHashMap

Inherits:
Object
  • Object
show all
Defined in:
lib/antlr4/runtime/flexible_hash_map.rb

Direct Known Subclasses

PredictionMode::AltAndContextMap

Defined Under Namespace

Classes: Entry

Constant Summary collapse

INITIAL_CAPACITY =

must be power of 2

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INITIAL_BUCKET_CAPACITY = 
8
LOAD_FACTOR = 
0.75

Instance Method Summary collapse

Constructor Details

#initialize(comparator = nil, initial_capacity = nil, initial_bucket_capacity = nil) ⇒ FlexibleHashMap

Returns a new instance of FlexibleHashMap.



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# File 'lib/antlr4/runtime/flexible_hash_map.rb', line 21

def initialize(comparator = nil, initial_capacity = nil, initial_bucket_capacity = nil)
  comparator = ObjectEqualityComparator.instance if comparator.nil?

  initial_capacity = INITIAL_CAPACITY if initial_capacity.nil?
  initial_bucket_capacity = INITIAL_BUCKET_CAPACITY if initial_bucket_capacity.nil?

  @n_items = 0
  @threshold = initial_capacity * LOAD_FACTOR # when to expand
  @current_prime = 1 # jump by 4 primes each expand or whatever
  @initial_bucket_capacity = initial_bucket_capacity
  @comparator = comparator
  @buckets = create_entry_list_array(initial_bucket_capacity)
end

Instance Method Details

#bucket(key) ⇒ Object 



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# File 'lib/antlr4/runtime/flexible_hash_map.rb', line 39

def bucket(key)
  hash = @comparator.hash(key)
  hash & (@buckets.length - 1) # assumes len is power of 2
end

#clear ⇒ Object 



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# File 'lib/antlr4/runtime/flexible_hash_map.rb', line 185

def clear
  @buckets = create_entry_list_array(INITIAL_CAPACITY)
  @n_items = 0
end

#contains_key(key) ⇒ Object 



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# File 'lib/antlr4/runtime/flexible_hash_map.rb', line 110

def contains_key(key)
  !get(key).nil?
end

#create_entry_list_array(length) ⇒ Object 



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# File 'lib/antlr4/runtime/flexible_hash_map.rb', line 35

def create_entry_list_array(length)
  Array.new(length)
end

#empty? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/antlr4/runtime/flexible_hash_map.rb', line 181

def empty?
  @n_items == 0
end

#expand ⇒ Object 



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# File 'lib/antlr4/runtime/flexible_hash_map.rb', line 147

def expand
  old = @buckets
  @current_prime += 4
  new_capacity = @buckets.length * 2
  new_table = create_entry_list_array(new_capacity)
  @buckets = new_table
  @threshold = new_capacity * LOAD_FACTOR

  old_size = size
  i = 0
  while i < old.length
    bucket = old[i]
    if bucket.nil?
      i += 1
      next
    end

    j = 0
    while j < bucket.length
      e = bucket[j]
      break if e.nil?

      put(e.key, e.value)
      j += 1
    end
    i += 1
  end
  @n_items = old_size
end

#get(key) ⇒ Object 



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# File 'lib/antlr4/runtime/flexible_hash_map.rb', line 44

def get(key)
  typed_key = key
  return nil if key.nil?

  b = bucket(typed_key)
  bucket = @buckets[b]
  if bucket.nil?
    return nil # no bucket
  end

  i = 0
  while i < bucket.length
    e = bucket[i]
    return e.value if @comparator.equals(e.key, typed_key)
    i += 1
  end
  nil
end

#hash ⇒ Object 



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# File 'lib/antlr4/runtime/flexible_hash_map.rb', line 114

def hash
  objs = []
  i = 0
  while i < @buckets.length
    bucket = @buckets[i]
    if bucket.nil?
      i += 1
      next
    end

    j = 0
    while j < bucket.length
      e = bucket[j]
      break if e.nil?

      objs << e.key
      j += 1
    end
    i += 1
  end

  hash_code = RumourHash.calculate(objs)

  unless @_hash.nil?
    if hash_code == @_hash
      puts 'Same hash_code for FlexibleHashMap'
    else
      puts 'Different hash_code for FlexibleHashMap'
    end
  end
  @_hash = hash_code
end

#put(key, value) ⇒ Object 



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# File 'lib/antlr4/runtime/flexible_hash_map.rb', line 63

def put(key, value)
  return nil if key.nil?

  expand if @n_items > @threshold
  b = bucket(key)
  bucket = @buckets[b]
  bucket = @buckets[b] = [] if bucket.nil?
  i = 0
  while i < bucket.length
    e = bucket[i]
    unless @comparator.equals(e.key, key)
      i += 1
      next
    end

    prev = e.value
    e.value = value
    @n_items += 1
    return prev
  end
  # not there
  bucket << Entry.new(key, value)
  @n_items += 1
  nil
end

#size ⇒ Object 



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# File 'lib/antlr4/runtime/flexible_hash_map.rb', line 177

def size
  @n_items
end

#to_s ⇒ Object 



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# File 'lib/antlr4/runtime/flexible_hash_map.rb', line 190

def to_s
  return 'end' if size == 0

  buf = ''
  buf << ''
  first = true
  @buckets.each do |bucket|
    next if bucket.nil?

    bucket.each do |e|
      break if e.nil?

      if first
        first = false
      else
        buf << ', '
      end
      buf << e.to_s
    end
  end
  buf << 'end'
  buf.to_s
end

#to_table_string ⇒ Object 



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# File 'lib/antlr4/runtime/flexible_hash_map.rb', line 214

def to_table_string
  buf = ''
  @buckets.each do |bucket|
    if bucket.nil?
      buf << "nil\n"
      next
    end
    buf << '['
    first = true
    bucket.each do |e|
      first ? first = false : buf << ' '
      buf << (e.nil? ? '_' : e.to_s)
    end
    buf << "]\n"
  end
  buf.to_s
end

#values ⇒ Object 



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# File 'lib/antlr4/runtime/flexible_hash_map.rb', line 89

def values
  a = []
  i = 0
  while i < @buckets.length
    bucket = @buckets[i]
    if bucket.nil?
      i += 1
      next
    end

    j = 0
    while j < bucket.length
      e = bucket[j]
      a << e.value
      j += 1
    end
    i += 1
  end
  a
end