master: transpose function, cleanup

lib/toycipher/toycipherutil.rb

@@ -1,63 +1,75 @@
 
 module ToyCipher
-
   # Utility Class, provides pretty print, distribution graph, etc.
-  #
   module ToyCipherUtil
+    EN_US_FREQ_RANK = %w(E R S T L N) unless defined?(EN_US_FREQ_RANK)
 
     def frequency(str, alph = @@ALPH)
       dist_pp distribution(normalize(str), alph) 
     end
 
-    EN_US_FREQ_RANK = %w(E R S T L N) unless defined?(EN_US_FREQ_RANK)
-
     def show_en_us_freq_rank
       puts EN_US_FREQ_RANK.join * ', '
     end
 
-    # Generate alphabet
-    #
     def generate_alphabet
       alph = []
       ('A'..'Z').each { |l| alph << l }
       alph
     end
 
-
-     # Find the frequency of each character in alph
-     #
-     def distribution(str, alph)
-       dist = {}
-       alph.each { |l| dist[l] = 0 }
-       str.each_byte { |b| dist[b.chr] = dist[b.chr] + 1 }
-       dist
-     end
-
-     def map_dist_to_rank(dist, alph = EN_US_FREQ_RANK)
-       dist_to_rank = {}
-       dist.invert.keys.sort.map.each { |count|
-       }
-     end
+    def distribution(str, alph)
+      dist = {}
+      alph.each { |l| dist[l] = 0 }
+      str.each_byte { |b| dist[b.chr] = dist[b.chr] + 1 }
+      dist
+    end
+    def map_dist_to_rank(dist, alph = EN_US_FREQ_RANK)
+      dist_to_rank = {}
+      dist.invert.keys.sort.map.each { |count|
+      }
+    end
 
-     # Pretty Print of a character frequency hash
-     #
-     def dist_pp(dist)
-       keys = dist.keys.sort
-       keys.each { |l| 
-         print "#{l}: "; dist[l].times do print "#" end
-         (30 - dist[l]).times { print " " }
-         print "(#{dist[l]})\n"
-       }
-     end
+    # Pretty Print of a character frequency hash
+    #
+    def dist_pp(dist)
+      keys = dist.keys.sort
+      keys.each { |l| 
+        print "#{l}: "; dist[l].times do print "#" end
+        (30 - dist[l]).times { print " " }
+        print "(#{dist[l]})\n"
+      }
+    end
 
-     # Normalize a string.  Remove non-alphanumeric characters and upcase it.
-     # 
-     def normalize(str) str.gsub(/\W/, '').upcase end
+    # Normalize a string.  Remove non-alphanumeric characters and upcase it.
+    # 
+    def normalize(str) str.gsub(/\W/, '').upcase end
 
-     def file2array(file)
-       IO.readlines(file)
-     end
-
-  end # ToyCipherUtil
+    # This does a matrix transposition on an m x n array of strings,
+    # returning n x m
+    def self.transpose2(arr)
+      cols = arr.first.size
+      raise Exception, "#{self.class}: Inconsistent string lengths in matrix! " if arr.any? { |l| l.size != cols } 
+      rows = arr.size
+      ans  = [] 
+      (0..cols-1).each do |col|
+        #puts "Working on col: #{col} in str #{arr[col]}"
+        ans << ''
+        (0..rows-1).each do |row|
+          #puts arr[row][col].chr
+          ans[col] += arr[row][col].chr
+        end
+      end
+      ans 
+    end
+
+    def self.transpose(arr)
+      cols = arr.first.size
+      raise Exception, "#{self.class}: Inconsistent string lengths in matrix! " if arr.any? { |l| l.size != cols } 
+      arr.inject([]) { |acc, l| 
+        acc << l.split(//) 
+      }.transpose.inject([]) { |acc, l| acc << l.join }
+    end
 
+  end # ToyCipherUtil
 end # ToyCipher