isbn_checker.rb

#!/usr/bin/ruby
#
# Copyright (c) 2010, John D. Lewis <balinjdl at gmail.com>
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:
#
#    * Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
#    * Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
#    * Neither the name of the author nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#

class Isbn_checker
  def verify_checkDigit(isbn_in, printValids)
    if isbn_in.length == 13
      return verify_checkDigit13(isbn_in.upcase, printValids)
    elsif isbn_in.length == 10
      return verify_checkDigit10(isbn_in.upcase, printValids)
    else
      return nil
    end
  end

  def verify_checkDigit10(isbn_in, printValids)
    retVal = false
    if (isbn_in.length == 10) 
      chkDgtX = calc_checkDigit10(isbn_in[0,isbn_in.length-1])
      #puts "chkDgtX = #{chkDgtX}; isbn_in = #{isbn_in}; isbn(substr) = #{isbn_in[0,isbn_in.length-1]}"
      if isbn_in == isbn_in[0,isbn_in.length-1].to_s + chkDgtX.to_s.upcase
	retVal=true
	if printValids
	  puts "valid check digit found in isbn #{isbn_in}!"
	end
      else
	puts "INVALID check digit in isbn #{isbn_in}!"
      end
    else
      puts "invalid isbn_in length (#{isbn_in.length})"
    end
    retVal
  end
  
  def verify_checkDigit13(isbn_in, printValids)
    retVal = false
    if (isbn_in.length == 13) 
      chkDgt = calc_checkDigit13(isbn_in[0,isbn_in.length-1])
      #puts "chkDgt = #{chkDgt}; isbn_in = #{isbn_in}; isbn(substr) = #{isbn_in[0,isbn_in.length-1]}"
      if isbn_in == isbn_in[0,isbn_in.length-1].to_s + chkDgt.to_s
	retVal=true
	if printValids
	  puts "valid check digit found in isbn #{isbn_in}!"
	end
      else
	puts "INVALID check digit in isbn #{isbn_in}!"
      end
    else
      puts "invalid isbn_in length (#{isbn_in.length})"
    end
    retVal
  end

  def calc_checkDigit(isbn_in)
    if isbn_in.length == 13
      return calc_checkDigit13(isbn_in)
    elsif isbn_in.length == 10
      return calc_checkDigit10(isbn_in)
    else
      return nil
    end
  end
  
  def calc_checkDigit10(isbn_in)
    charPos = 0
    csumTotal = 0
    iarr = isbn_in.split(//)
    for i2 in iarr
      charPos += 1
      csumTotal = csumTotal + (charPos * i2.to_i)
      #puts "csumTotal (running) = #{csumTotal}"
    end
    #puts "csumTotal = #{csumTotal}"
    checkDigit = csumTotal % 11
    if (checkDigit == 10)
      checkDigit = "X"
    end
    #puts "for partial isbn #{isbn_in} the checkDigit = #{checkDigit}; complete isbn = #{isbn_in}#{checkDigit}"
    checkDigit
  end
  
  def calc_checkDigit13(isbn_in)
    charPos = 0
    csumTotal = 0
    iarr = isbn_in.split(//)
    for i1 in iarr
      cP2 = charPos/2.to_f
      #puts "#{cP2}; #{cP2.round}; #{cP2.floor}"
      
      if (cP2.round == cP2.floor)
	csumTotal = csumTotal + i1.to_i
	#puts "csumTotal_a = #{csumTotal} + #{i1.to_i}"
      else
	csumTotal = csumTotal + (3*i1.to_i)
	#puts "csumTotal_b = #{csumTotal} + #{3*i1.to_i}"
      end      
      charPos += 1
    end
      #puts "csumTotal = #{csumTotal}"
      if (csumTotal == (csumTotal/10.to_i)*10)
	checkDigit = "0"
      else
	checkDigit = 10-(csumTotal - (csumTotal/10.to_i)*10)
      end
      
      #puts "checkDigit = 10-(#{csumTotal} - #{(csumTotal/10.to_i)*10})"
      if (checkDigit == 10)
	checkDigit = "X"
      end
      #puts "for partial isbn #{isbn_in} the checkDigit = #{checkDigit}; complete isbn = #{isbn_in}#{checkDigit}"
      checkDigit
  end
  
  def fix_isbn(isbn)  
    return isbn[0,isbn.length-1] + calc_checkDigit(isbn).to_s
  end
  
  def check_isbnFile(filename)
    isbns_checked = isbns_valid = isbns_invalid = 0
    
    File.open(filename, "r") do |f|
      f.each { |isbn|
        isbn = isbn.chomp
	if verify_checkDigit(isbn, false) == false
	  puts "#{isbn} is invalid; proper ISBN should be " + fix_isbn(isbn)
          isbns_invalid +=1
        else
	  isbns_valid+=1
        end
        isbns_checked += 1
      }
    end
    puts "checked #{isbns_checked} isbns; #{isbns_invalid} invalid (#{(isbns_invalid/isbns_checked)*100.round}%) & #{isbns_valid} valid (#{(isbns_valid/isbns_checked)*100.round}%)"
  end
  
  def initialize()
  end
  
  def new
  end
end