Sha256: 70d0dedba9a2f6efa852d2928d2ab0ba7d5a632ba7d04fdf21ccefb022655b9e
Contents?: true
Size: 919 Bytes
Versions: 16
Compression:
Stored size: 919 Bytes
Contents
require "petrarca/helpers"
module Petrarca
module ISBN10
extend self
def valid?(isbn)
isbn = isbn.to_s
if correct_format?(isbn) && isbn[-1] == calc_check_digit(isbn)
if isbn.include?("-")
Helpers.split("978" + isbn).drop(1) == isbn.split("-")
else
true
end
else
false
end
end
def correct_format?(isbn)
isbn = isbn.to_s.delete("-")
!!(/\A\d{9}[0-9X]\z/ =~ isbn)
end
def calc_check_digit(isbn)
nums = isbn.to_s.delete("-").split("")[0, 9].map{|x| x.to_i }
sum = nums.zip((2..10).to_a.reverse).map{|x, y| x * y }.inject(:+)
check_digit = 11 - (sum % 11)
case check_digit
when 10
"X"
when 11
"0"
else
check_digit.to_s
end
end
def hyphenate(isbn)
Helpers.split("978" + isbn.to_s).drop(1).join("-")
end
end
end
Version data entries
16 entries across 16 versions & 1 rubygems