1 files changed, 44 insertions, 0 deletions
diff --git a/lib/knapsack_solver/dataset.rb b/lib/knapsack_solver/dataset.rb
new file mode 100644
index 0000000..b38e9e5
--- /dev/null
+++ b/lib/knapsack_solver/dataset.rb
@@ -0,0 +1,44 @@
+require 'knapsack_solver/instance'
+
+module KnapsackSolver
+  # This class represents a set of 0/1 knapsack problem instances.
+  class Dataset
+    # Initializes set of 0/1 knapsack problem instances.
+    #
+    # @param id [Integer] Dataset ID number.
+    # @param instances [Array<Instance>] set of the 0/1 knapsack problem instances.
+    def initialize(id, instances)
+      @id = id
+      @instances = instances
+    end
+
+    # Parses set of a 0/1 knapsack problem instances from a character stream.
+    #
+    # @param stream [#eof?,#readline,#each_line] character stream holding the dataset.
+    # @return [Dataset] dataset instance parsed from the stream.
+    def self.parse(stream)
+      id = parse_id(stream)
+      instances = stream.each_line.with_object([]) { |l, o| o << Instance.parse(l) }
+      raise StandardError, 'dataset: missing instances' if instances.empty?
+      Dataset.new(id, instances)
+    end
+
+    # Parses ID of a 0/1 knapsack problem dataset from a character stream.
+    #
+    # @param stream [#eof?,#readline,#each_line] character stream holding the dataset.
+    # @return [Integer] dataset ID number.
+    def self.parse_id(stream)
+      raise StandardError, 'dataset: missing ID' if stream.eof?
+      s = stream.readline.split
+      raise StandardError, 'dataset: first line does not contain ID' if s.size != 1
+      begin
+        raise StandardError, 'dataset: ID is negative' if Integer(s.first) < 0
+      rescue ArgumentError
+        raise StandardError, 'dataset: ID is not an integer'
+      end
+      Integer(s.first)
+    end
+
+    attr_reader :id, :instances
+  end
+end