Add bin and edit workflow

bin/gems/ttfunk-1.8.0/lib/ttfunk/table/dsig.rb

@@ -0,0 +1,93 @@
+# frozen_string_literal: true
+
+module TTFunk
+  class Table
+    # Digital Signature (`DSIG`) table.
+    class Dsig < Table
+      # Signature record.
+      class SignatureRecord
+        # Format of the signature.
+        # @return [Integer]
+        attr_reader :format
+
+        # Length of signature in bytes.
+        # @return [Integer]
+        attr_reader :length
+
+        # Offset to the signature block from the beginning of the table.
+        # @return [Integer]
+        attr_reader :offset
+
+        # Signature PKCS#7 packet.
+        # @return [String]
+        attr_reader :signature
+
+        # @param format [Integer]
+        # @param length [Integer]
+        # @param offset [Integer]
+        # @param signature [String]
+        def initialize(format, length, offset, signature)
+          @format = format
+          @length = length
+          @offset = offset
+          @signature = signature
+        end
+      end
+
+      # Version umber of this table.
+      # @return [Integer]
+      attr_reader :version
+
+      # Permission flags.
+      # @return [Integer]
+      attr_reader :flags
+
+      # Signature records.
+      # @return [Array<SignatureRecord>]
+      attr_reader :signatures
+
+      # Table tag.
+      TAG = 'DSIG'
+
+      # Encode table.
+      #
+      # **Note**: all signatures will be lost. This encodes an empty table
+      # regardless whether the supplied table contains any signtaures or not.
+      #
+      # @param dsig [TTFunk::Table::Dsig]
+      # @return [String]
+      def self.encode(dsig)
+        return unless dsig
+
+        # Don't attempt to re-sign or anything - just use dummy values.
+        # Since we're subsetting that should be permissible.
+        [dsig.version, 0, 0].pack('Nnn')
+      end
+
+      # Table tag.
+      #
+      # @return [String]
+      def tag
+        TAG
+      end
+
+      private
+
+      def parse!
+        @version, num_signatures, @flags = read(8, 'Nnn')
+
+        @signatures =
+          Array.new(num_signatures) {
+            format, length, sig_offset = read(12, 'N3')
+            signature =
+              parse_from(offset + sig_offset) {
+                _, _, sig_length = read(8, 'nnN')
+                read(sig_length, 'C*')
+              }
+
+            SignatureRecord.new(format, length, sig_offset, signature)
+          }
+      end
+    end
+  end
+end