1 files changed, 87 insertions, 0 deletions
diff --git a/lib/asn1kit/types/integer.rb b/lib/asn1kit/types/integer.rb
new file mode 100644
index 0000000..9104a5d
--- /dev/null
+++ b/lib/asn1kit/types/integer.rb
@@ -0,0 +1,87 @@
+# coding: ASCII-8BIT
+
+class ASN1Kit::Integer < ASN1Kit::Type
+  asn1_tag :IMPLICIT, :UNIVERSAL, 2
+  asn1_alias "INTEGER"
+
+  NAMED_NUMBERS = {}
+  NAMED_NUMBERS_INVERTED = {}
+
+  class << self
+    def [](*named_numbers)
+      return self if named_numbers.empty?
+      ret = Class.new(self)
+      hash = named_numbers.to_h
+      hash_inverted = hash.invert
+      raise "duplicate name(s) in named number list" if named_numbers.size != hash.size
+      raise "duplicate value(s) in named number list" if hash.size != hash_inverted.size
+      ret.const_set(:NAMED_NUMBERS, hash)
+      ret.const_set(:NAMED_NUMBERS_INVERTED, hash.invert)
+      ret
+    end
+
+    def named_number(name)
+      self::NAMED_NUMBERS[name]
+    end
+
+    def named_numbers
+      self::NAMED_NUMBERS.keys
+    end
+
+    private def inspect_inner
+      return nil if self::NAMED_NUMBERS.empty?
+      nns = self::NAMED_NUMBERS.map { |name, value| "#{name}(#{value})" }.join(", ")
+      "{ #{nns} }"
+    end
+  end
+
+  attr_reader :value
+
+  def initialize(value)
+    case value
+    when Integer
+      @value = value
+    when String
+      @value = self.class::NAMED_NUMBERS[value] or
+        raise ArgumentError, "invalid name %p" % value
+    else
+      raise TypeError, "invalid value: %p (expected an Integer or a NamedValue label)" % value
+    end
+  end
+
+  def name
+    self.class::NAMED_NUMBERS_INVERTED[@value]
+  end
+
+  def to_der
+    v = @value
+    if v >= 0
+      dig = v.digits(256)
+      dig << 0x00 if dig[-1] >= 0x80
+      s = dig.pack("C*").reverse
+    else
+      v = ~v
+      dig = v.digits(256)
+      dig << 0x00 if dig[-1] >= 0x80
+      s = dig.map!(&:~).pack("C*").reverse
+    end
+    der_header(s.bytesize) << s
+  end
+
+  def ==(other)
+    other.class <= ASN1Kit::Integer && value == other.value
+  end
+
+  def cast_to(type)
+    return type.new(@value) if type <= ASN1Kit::Integer
+    super
+  end
+
+  private def inspect_inner
+    if n = name
+      "#{@value}(#{n})"
+    else
+      "#{@value}"
+    end
+  end
+end