Publication ranges

README.md

@@ -36,12 +36,26 @@ You can convert it to ISBN-10 or ISBN-13:
     > isbn.isbn13
      => "9780000000002"
 
-And you can break it up into its GS1 prefix, group identifier, prefix/publisher code,
+You can break it up into its GS1 prefix, group identifier, prefix/publisher code,
 item number and check digit:
 
     > isbn.parts
      => ["978", "0", "00", "000000", "2"]
-
+
+You can generate the complete range of ISBNs for a registrant element, using the publisher_range object:
+
+    > isbn.publisher_range.isbn13s
+     => ["9786017002008", "9786017002015", "9786017002022", .. "9786017002992"]
+
+You can create a publication range object directly:
+
+    > Lisbn::PublicationRange.new("9786017002008")
+
+You can see the range as a string representation:
+
+    > Lisbn::PublicationRange.new("9786017002008").to_s
+     => "978-601-7002-00-8..978-601-7002-99-2"
+
 ## Updating
 
 You can update the ISBN ranges by replacing the RangeMessage.xml file with an

lib/lisbn.rb

@@ -3,3 +3,4 @@
 require_relative "lisbn/cache_method"
 require_relative "lisbn/lisbn"
 require_relative "lisbn/ranges"
+require_relative "lisbn/publication_range"

lib/lisbn/lisbn.rb

@@ -45,6 +45,16 @@ def isbn13
     '978' + isbn[0..-2] + isbn_13_checksum
   end
 
+  def isbn13_checksum_corrected
+    return nil unless isbn.length == 13
+    isbn[0..-2] + isbn_13_checksum
+  end
+
+  def publication_range
+    return unless isbn13
+    PublicationRange.new(isbn13)
+  end
+
   # Returns an Array with the 'parts' of the ISBN-13 in left-to-right order.
   # The parts of an ISBN are as follows:
   #   - GS1 prefix

lib/lisbn/publication_range.rb

@@ -0,0 +1,57 @@
+class Lisbn < String
+  class PublicationRange
+    include Enumerable
+    def initialize(seed_isbn13)
+      @seed_isbn13 = Lisbn.new(seed_isbn13)
+    end
+
+    def parts
+      seed_isbn13.parts[0..2]
+    end
+
+    def prefix
+      parts.join
+    end
+
+    def to_s
+      "#{Lisbn.new(from).isbn_with_dash}..#{Lisbn.new(to).isbn_with_dash}"
+    end
+
+    def number_of_publications
+      10 ** (13 - prefix.size - 1)
+    end
+
+    def publication_numbers
+      (0..(number_of_publications-1))
+    end
+
+    def each
+      (from_prefix..to_prefix).each do |isbn|
+        yield Lisbn.new((isbn*10).to_s).isbn13_checksum_corrected
+      end
+    end
+
+    private
+    attr_reader :seed_isbn13
+
+    def multiplier
+      (10 ** (12 - prefix.size))
+    end
+
+    def from_prefix
+      prefix.to_i * multiplier
+    end
+
+    def to_prefix
+      (prefix.to_i+1) * multiplier - 1
+    end
+
+    def from
+      Lisbn.new((from_prefix*10).to_s).isbn13_checksum_corrected
+    end
+
+    def to
+      Lisbn.new((to_prefix*10).to_s).isbn13_checksum_corrected
+    end
+  end
+end

spec/lisbn_spec.rb

@@ -127,6 +127,16 @@
       lisbn.should_not_receive(:isbn_13_checksum)
       lisbn.isbn13.should == "9780000000002"
     end
+
+    it "provides a corrected checksum" do
+      lisbn = Lisbn.new("9780000000001")
+      lisbn.isbn13_checksum_corrected.should == "9780000000002"
+    end
+
+    it "can generate a publication range" do
+      lisbn = Lisbn.new("9786017002015")
+      lisbn.publication_range.to_s.should == "978-601-7002-00-8..978-601-7002-99-2"
+    end
   end
 
   describe "#parts" do
@@ -147,6 +157,138 @@
     end
   end
 
+  describe "#publication_range" do
+    subject { Lisbn::PublicationRange.new("9786017002015") }
+
+    it "returns a PublicationRange object" do
+      subject.class.should == Lisbn::PublicationRange
+    end
+
+    it "returns the three parts of a PublicationRange" do
+      subject.parts.should == ["978", "601", "7002"]
+    end
+
+    it "returns the number of publication in the range" do
+      subject.number_of_publications.should == 100
+    end
+
+    it "returns the range of publication numbers" do
+      subject.publication_numbers.should == (0..99)
+    end
+
+    it "returns a string representation of the range of ISBN13s" do
+      subject.to_s.should == "978-601-7002-00-8..978-601-7002-99-2"
+    end
+
+    it "returns an enumerable of isbns" do
+      subject.min.should == "9786017002008"
+      subject.max.should == "9786017002992"
+
+      subject.map{|x| x}.should == [
+        "9786017002008",
+        "9786017002015",
+        "9786017002022",
+        "9786017002039",
+        "9786017002046",
+        "9786017002053",
+        "9786017002060",
+        "9786017002077",
+        "9786017002084",
+        "9786017002091",
+        "9786017002107",
+        "9786017002114",
+        "9786017002121",
+        "9786017002138",
+        "9786017002145",
+        "9786017002152",
+        "9786017002169",
+        "9786017002176",
+        "9786017002183",
+        "9786017002190",
+        "9786017002206",
+        "9786017002213",
+        "9786017002220",
+        "9786017002237",
+        "9786017002244",
+        "9786017002251",
+        "9786017002268",
+        "9786017002275",
+        "9786017002282",
+        "9786017002299",
+        "9786017002305",
+        "9786017002312",
+        "9786017002329",
+        "9786017002336",
+        "9786017002343",
+        "9786017002350",
+        "9786017002367",
+        "9786017002374",
+        "9786017002381",
+        "9786017002398",
+        "9786017002404",
+        "9786017002411",
+        "9786017002428",
+        "9786017002435",
+        "9786017002442",
+        "9786017002459",
+        "9786017002466",
+        "9786017002473",
+        "9786017002480",
+        "9786017002497",
+        "9786017002503",
+        "9786017002510",
+        "9786017002527",
+        "9786017002534",
+        "9786017002541",
+        "9786017002558",
+        "9786017002565",
+        "9786017002572",
+        "9786017002589",
+        "9786017002596",
+        "9786017002602",
+        "9786017002619",
+        "9786017002626",
+        "9786017002633",
+        "9786017002640",
+        "9786017002657",
+        "9786017002664",
+        "9786017002671",
+        "9786017002688",
+        "9786017002695",
+        "9786017002701",
+        "9786017002718",
+        "9786017002725",
+        "9786017002732",
+        "9786017002749",
+        "9786017002756",
+        "9786017002763",
+        "9786017002770",
+        "9786017002787",
+        "9786017002794",
+        "9786017002800",
+        "9786017002817",
+        "9786017002824",
+        "9786017002831",
+        "9786017002848",
+        "9786017002855",
+        "9786017002862",
+        "9786017002879",
+        "9786017002886",
+        "9786017002893",
+        "9786017002909",
+        "9786017002916",
+        "9786017002923",
+        "9786017002930",
+        "9786017002947",
+        "9786017002954",
+        "9786017002961",
+        "9786017002978",
+        "9786017002985",
+        "9786017002992"
+      ]
+    end
+  end
+
   describe "ranges" do
     it "skips over invalid '0-length' ranges" do
       Lisbn::RANGES.values.flatten.map {|v| v[:length]}.should_not include(0)
@@ -157,7 +299,8 @@
     subject { Lisbn.new("9780000000002") }
 
     it "#splits" do
-      subject.split("7").should == ["9", "80000000002"]
+      subject.split("7").should == ["9",
+        "80000000002"]
     end
   end
 end