Class: String

Inherits:
Object show all
Defined in:
lib/zip/stdrubyext.rb,
lib/quiz1/t/solutions/Carlos/solitaire.rb

Overview

:nodoc:all

Instance Method Summary collapse

Instance Method Details

#crypt(deck, decrypt = false) ⇒ Object 



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# File 'lib/quiz1/t/solutions/Carlos/solitaire.rb', line 26

def crypt (deck, decrypt=false)
	numbers = to_numbers
	keystream = deck.generate_keystream numbers.length
	result = ""
	numbers.zip(keystream) do |n, k|
		k = -k if decrypt
		result << (n+k).to_letter
	end
	result
end

#decrypt(deck) ⇒ Object 



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# File 'lib/quiz1/t/solutions/Carlos/solitaire.rb', line 41

def decrypt (deck)
	crypt deck, true
end

#encrypt(deck) ⇒ Object 



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# File 'lib/quiz1/t/solutions/Carlos/solitaire.rb', line 37

def encrypt (deck)
	crypt deck, false
end

#ends_with(aString) ⇒ Object 



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# File 'lib/zip/stdrubyext.rb', line 40

def ends_with(aString)
  index(aString, -aString.size)
end

#ensure_end(aString) ⇒ Object 



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# File 'lib/zip/stdrubyext.rb', line 44

def ensure_end(aString)
  ends_with(aString) ? self : self + aString
end

#lchop ⇒ Object 



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# File 'lib/zip/stdrubyext.rb', line 48

def lchop
  slice(1, length)
end

#starts_with(aString) ⇒ Object 



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# File 'lib/zip/stdrubyext.rb', line 36

def starts_with(aString)
  rindex(aString, 0) == 0
end

#to_numbers ⇒ Object

returns an array with the code of the letters, padded with the code of X



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# File 'lib/quiz1/t/solutions/Carlos/solitaire.rb', line 14

def to_numbers
	res=upcase.unpack("C*").collect { |b|
		if b.between? ?A, ?Z
			b - ?A + 1
		else
			nil
		end
	}.compact
	# 24 == X
	res.fill 24, res.length, (5 - res.length % 5) % 5
end