Class: Diff::GDiff::Operations::Data

Inherits:
Object
  • Object
show all
Defined in:
lib/gdiff.rb

Overview

Insert Data operation

Automatically splits itself into multiple operations on pack if neccessary. #pack chooses smallest possible representation.

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(data) ⇒ Data

Create a new Data operation that inserts the given data at this point



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# File 'lib/gdiff.rb', line 29

def initialize(data)
  @data = data
end

Instance Attribute Details

#data ⇒ Object (readonly)

Returns the value of attribute data.



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# File 'lib/gdiff.rb', line 26

def data
  @data
end

Class Method Details

.unpack_if_match(string, position) ⇒ Object

Takes a string and a position and returns the position after this operation and a new operation object if the operation starting at the position is a Data operation. Otherwise returns nil.



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# File 'lib/gdiff.rb', line 66

def self.unpack_if_match(string, position)
  if string[position] < 245
    length = string[position]
    operation = self.new(string[position+1, length])
    position += length + 1
    return position, operation
  elsif (type = {247 => USHORT, 248 => INT}[string[position]])
    length = string[position + 1, type[2]].unpack(type[0])[0]
    operation = self.new(string[position + 1 + type[2], length])
    position += operation.data.length + 1 + type[2]
    return position, operation
  end
  nil
end

Instance Method Details

#length ⇒ Object

return the length of the data object to insert



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# File 'lib/gdiff.rb', line 34

def length
  @data.length
end

#pack ⇒ Object

Return a binary representation in gdiff format of the Data operation

The binary representation may consist of multiple Data operations if neccessary.



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# File 'lib/gdiff.rb', line 42

def pack
  result = ""
  d = @data
  while d.length > 0
    if d.length < 246
      result << [d.length].pack("C") << d
      d = ""
    elsif d.length < USHORT[1]
      result << [247, d.length].pack("C" << USHORT[0]) << d
      d = ""
    elsif d.length < INT[1]
      result << [248, d.length].pack("C" << INT[0]) << d
      d = ""
    else
      result << [248, INT[1]].pack("C" << INT[0]) << d[0...INT[1]]
      d = d[INT[1]..-1]
    end
  end
  result
end

#to_s ⇒ Object

Return a readable representation of the operation



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# File 'lib/gdiff.rb', line 82

def to_s
  d = @data.inspect
  "Insert " << (d.length < 60 ? d : d[0..20] << "..." << d[-37..-1])
end