Class: SaxStream::CoreExtensions::OrderedHash

Inherits:
Hash
  • Object
show all
Includes:
Enumerable
Defined in:
lib/sax_stream/core_extensions/ordered_hash.rb,
lib/sax_stream/core_extensions/ordered_hash.rb

Overview

This class is based on the Ruby 1.9 ordered hashes.

It keeps the semantics and most of the efficiency of normal hashes while also keeping track of the order in which elements were set.

Defined Under Namespace

Classes: Node

Instance Method Summary collapse

Constructor Details

#initialize ⇒ OrderedHash

Returns a new instance of OrderedHash.



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# File 'lib/sax_stream/core_extensions/ordered_hash.rb', line 19

def initialize
  @hash = {}
end

Instance Method Details

#[](key) ⇒ Object 



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# File 'lib/sax_stream/core_extensions/ordered_hash.rb', line 23

def [](key)
  @hash[key] && @hash[key].value
end

#[]=(key, value) ⇒ Object 



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# File 'lib/sax_stream/core_extensions/ordered_hash.rb', line 27

def []=(key, value)
  if node = @hash[key]
    node.value = value
  else
    node = Node.new(key, value)

    if @first.nil?
      @first = @last = node
    else
      node.prev = @last
      @last.next = node
      @last = node
    end
  end

  @hash[key] = node
  value
end

#delete(key) ⇒ Object 



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# File 'lib/sax_stream/core_extensions/ordered_hash.rb', line 46

def delete(key)
  if node = @hash[key]
    prev_node = node.prev
    next_node = node.next

    next_node.prev = prev_node if next_node
    prev_node.next = next_node if prev_node

    @first = next_node if @first == node
    @last = prev_node  if @last  == node

    value = node.value
  end

  @hash.delete(key)
  value
end

#each {|[@first.key, @first.value]| ... } ⇒ Object

Yields:

  • ([@first.key, @first.value]) 


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# File 'lib/sax_stream/core_extensions/ordered_hash.rb', line 72

def each
  return unless @first
  yield [@first.key, @first.value]
  node = @first
  yield [node.key, node.value] while node = node.next
  self
end

#empty? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/sax_stream/core_extensions/ordered_hash.rb', line 102

def empty?
  @hash.empty?
end

#keys ⇒ Object 



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# File 'lib/sax_stream/core_extensions/ordered_hash.rb', line 64

def keys
  self.map { |k, v| k }
end

#merge(other) ⇒ Object 



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# File 'lib/sax_stream/core_extensions/ordered_hash.rb', line 88

def merge(other)
  hash = self.class.new

  self.each do |key, value|
    hash[key] = value
  end

  other.each do |key, value|
    hash[key] = value
  end

  hash
end

#to_hash ⇒ Object 



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# File 'lib/sax_stream/core_extensions/ordered_hash.rb', line 80

def to_hash
  result = {}
  self.each do |key, value|
    result[key] = value
  end
  result
end

#values ⇒ Object 



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# File 'lib/sax_stream/core_extensions/ordered_hash.rb', line 68

def values
  self.map { |k, v| v }
end