Class: LazyString

Inherits:
Object
  • Object
show all
Defined in:
lib/lazy-string.rb

Overview

Author

Natsuki Kawai ([email protected])

Copyright

Copyright © 2012 Natsuki Kawai

License

2-clause BSDL or Ruby’s

Defined Under Namespace

Classes: LazySubString, SubString

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(*args) ⇒ LazyString

Returns a new instance of LazyString.



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# File 'lib/lazy-string.rb', line 38

def initialize(*args)
  @size = 0
  @chain = []

  if args.size == 3
    @chain << SubString.new(0, LazySubString.new(*args))
    @size = args[2]
  end
end

Instance Attribute Details

#size ⇒ Object (readonly) Also known as: length

Returns the value of attribute size.



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# File 'lib/lazy-string.rb', line 114

def size
  @size
end

Instance Method Details

#<<(other) ⇒ Object

TODO: Add ‘add’ method to add a substring of a String.



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# File 'lib/lazy-string.rb', line 49

def <<(other)
  if other.respond_to?(:to_int)
    return self << ('' << other)
  end
  
  @chain << SubString.new(@size, other)
  @size += other.size
end

#[](*args) ⇒ Object 



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# File 'lib/lazy-string.rb', line 58

def [](*args)
  if args.size == 2
    start = args[0]
    last  = start + args[1]
    length = args[1]
    e = @chain.each
    
    curr = nil
    begin
      curr = e.next
    end while curr.start + curr.value.size < start
    
    value = curr.value
    sub_start = start - curr.start
    sub_length = value.size - sub_start
    if sub_length >= length
      return LazyString.new(value, sub_start, length)
    else
      res = LazyString.new(value, sub_start, sub_length)
      length -= sub_length
      while length > 0
        curr = e.next
        if length < curr.value.length
          res << LazyString.new(curr.value, 0, length)
          length = 0
        else
          res << curr.value
          length -= curr.value.length
        end
      end
      return res
    end
  elsif args.respond_to?(:to_int)
    warn "#{self.class.name}#[pos] has not implemented yet. Calling #{self.class.name}#to_str."
    to_str[*args]
  else # args is one Range object.
    warn "#{self.class.name}#[range] has not implemented yet. Calling #{self.class.name}#to_str."
    to_str[*args]
  end
end

#to_str ⇒ Object Also known as: to_s 



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# File 'lib/lazy-string.rb', line 105

def to_str
  res = ''
  @chain.each do |substr|
    res << substr.value
  end
  return res
end

#unpack(template) ⇒ Object 



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# File 'lib/lazy-string.rb', line 99

def unpack(template)
  # TODO: Optimize here.
  # (Stop concat the front strings if template start with "x".)
  to_str.unpack(template)
end