1 files changed, 58 insertions, 0 deletions
diff --git a/activesupport/lib/active_support/number_helper/number_to_human_size_converter.rb b/activesupport/lib/active_support/number_helper/number_to_human_size_converter.rb
new file mode 100644
index 0000000000..78d2c9ae6e
--- /dev/null
+++ b/activesupport/lib/active_support/number_helper/number_to_human_size_converter.rb
@@ -0,0 +1,58 @@
+module ActiveSupport
+  module NumberHelper
+    class NumberToHumanSizeConverter < NumberConverter #:nodoc:
+      STORAGE_UNITS = [:byte, :kb, :mb, :gb, :tb]
+
+      self.namespace      = :human
+      self.validate_float = true
+
+      def convert
+        @number = Float(number)
+
+        # for backwards compatibility with those that didn't add strip_insignificant_zeros to their locale files
+        unless options.key?(:strip_insignificant_zeros)
+          options[:strip_insignificant_zeros] = true
+        end
+
+        if smaller_than_base?
+          number_to_format = number.to_i.to_s
+        else
+          human_size = number / (base ** exponent)
+          number_to_format = NumberToRoundedConverter.convert(human_size, options)
+        end
+        conversion_format.gsub(/%n/, number_to_format).gsub(/%u/, unit)
+      end
+
+      private
+
+        def conversion_format
+          translate_number_value_with_default('human.storage_units.format', :locale => options[:locale], :raise => true)
+        end
+
+        def unit
+          translate_number_value_with_default(storage_unit_key, :locale => options[:locale], :count => number.to_i, :raise => true)
+        end
+
+        def storage_unit_key
+          key_end = smaller_than_base? ? 'byte' : STORAGE_UNITS[exponent]
+          "human.storage_units.units.#{key_end}"
+        end
+
+        def exponent
+          max = STORAGE_UNITS.size - 1
+          exp = (Math.log(number) / Math.log(base)).to_i
+          exp = max if exp > max # avoid overflow for the highest unit
+          exp
+        end
+
+        def smaller_than_base?
+          number.to_i < base
+        end
+
+        def base
+          opts[:prefix] == :si ? 1000 : 1024
+        end
+    end
+  end
+end
+