Make interface for weighting input smaller

The input object must now only respond to each and must contain
arrays.

lib/rubella/weighting/base.rb

@@ -20,7 +20,7 @@ module Rubella
       # @return Rubella::Weighting::Base
       # @raise ArgumentError
       #
-      def initialize(buckets = 10)
+      def initialize buckets = 10
         self.buckets = buckets
       end
 
@@ -31,7 +31,7 @@ module Rubella
       #
       def buckets= buckets
         # Must be divideable by 100
-        if([1, 2, 5, 10, 20, 50].index(buckets) == nil)
+        if [1, 2, 5, 10, 20, 50].index(buckets) == nil
           raise ArgumentError.new "Amount of buckets must be 1, 2, 5, 10, 20 "+
             "or 50"
         end

lib/rubella/weighting/expotential.rb

@@ -17,18 +17,13 @@ module Rubella
       # @param input Rubella::Input An input object
       # @return Rubella::Storage
       def parse input
-        data = input.data
-        # no data, no work
-        return [] if data.length == 0
-
-        # total amount of cores
-        total_amount = data[0].length
-
         # prepare data
-        data_list = Array.new()
-        bucket_no = 0
+        data_list    = Array.new()
+        bucket_no    = 0
+        total_amount = nil
 
-        data.each do |cores|
+        input.each do |cores|
+          total_amount = cores.length if total_amount.nil?
           # every 10 load percent one heatpoint
           i = 0
           data_list << Array.new(buckets) do

lib/rubella/weighting/per_overall_load.rb

@@ -18,14 +18,10 @@ module Rubella
       # @param input Rubella::Input An input object
       # @return Rubella::Storage
       def parse input
-        data = input.data
-        # no data, no work
-        return [] if data.length == 0
-
         # prepare data
         data_list = Array.new()
 
-        data.each do |cores|
+        input.each do |cores|
 
           # Add all loads to compute how much % is one % load
           load_sum = 0

lib/rubella/weighting/per_value.rb

@@ -4,7 +4,7 @@ module Rubella
   module Weighting
 
     # The Rubella::Weighting::PerValue object weights every bucket set to 1 in
-    # ammount. So if you have have for example four cores, every core is
+    # amount. So if you have have for example four cores, every core is
     # weighted to 0.25 no matter how much the load of a single core is. It's
     # just a "as is" weighting.
     #
@@ -17,17 +17,12 @@ module Rubella
       # @param input Rubella::Input An input object
       # @return Rubella::Storage
       def parse input
-        data = input.data
-        # no data, no work
-        return [] if data.length == 0
-
-        # total amount of cores
-        total_amount = data[0].length
-
         # prepare data
         data_list = Array.new()
+        total_amount = nil
 
-        data.each do |cores|
+        input.each do |cores|
+          total_amount = cores.length if total_amount.nil?
           # every 10 load percent one heatpoint
           i = 0
           data_list << Array.new(buckets) do