GH-50832: [Ruby] Add ArrowFormat::FixedSizeBinaryArray.new(byte_widt…h, values)

ruby/red-arrow-format/lib/arrow-format/array.rb

@@ -852,7 +852,21 @@ def type
   end
 
   class FixedSizeBinaryArray < Array
-    def initialize(type, size, validity_buffer, values_buffer)
+    include BufferAlignable
+
+    def initialize(type, *args)
+      unless type.is_a?(Type)
+        type = FixedSizeBinaryType.try_convert(type) || type
+      end
+      if args.size == 1
+        args = build_data(args.first, type)
+      elsif args.size != 3
+        raise ArgumentError,
+              "wrong number of arguments (given #{args.size + 1}, expected 2 or 4)"
+      end
+
+      size, validity_buffer, values_buffer = args
+
       super(type, size, validity_buffer)
       @values_buffer = values_buffer
     end
@@ -875,6 +889,44 @@ def to_a
       end
       apply_validity(values)
     end
+
+    private
+    def build_data(data, type)
+      n = 0
+      validity_buffer_builder = nil
+
+      values = +"".b
+      byte_width = type.byte_width
+      null_value = "\x00" * byte_width
+
+      data.each_with_index do |value, i|
+        if value.nil?
+          validity_buffer_builder ||= SparseBitmapBuilder.new
+          validity_buffer_builder.unset(i)
+          values.append_as_bytes(null_value)
+        else
+          unless value.bytesize == byte_width
+            message = "value size must be #{byte_width}: #{value.inspect}"
+            raise ArgumentError, message
+          end
+          values.append_as_bytes(value)
+        end
+
+        n += 1
+      end
+
+      validity_buffer = validity_buffer_builder&.finish(n)
+
+      pad!(values, buffer_padding_size(values))
+      values.freeze
+      values_buffer = IO::Buffer.for(values)
+
+      [
+        n,
+        validity_buffer,
+        values_buffer,
+      ]
+    end
   end
 
   class DecimalArray < FixedSizeBinaryArray

ruby/red-arrow-format/lib/arrow-format/type.rb

@@ -911,6 +911,20 @@ def to_flatbuffers
   end
 
   class FixedSizeBinaryType < Type
+    class << self
+      def try_convert(value)
+        case value
+        when Integer
+          byte_width = value
+          new(byte_width)
+        when self
+          value
+        else
+          nil
+        end
+      end
+    end
+
     attr_reader :byte_width
     def initialize(byte_width)
       super()

ruby/red-arrow-format/test/test-fixed-size-binary-array.rb

@@ -0,0 +1,79 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+
+class TestFixedSizeBinaryArray < Test::Unit::TestCase
+  sub_test_case("#initialize") do
+    def test_no_null
+      values = ["0124".b, "abcd".b]
+      assert_equal(values,
+                   ArrowFormat::FixedSizeBinaryArray.new(4, values).to_a)
+    end
+
+    def test_mixed
+      values = ["0124".b, nil, "abcd".b]
+      assert_equal(values,
+                   ArrowFormat::FixedSizeBinaryArray.new(4, values).to_a)
+    end
+
+    def test_type
+      type = ArrowFormat::FixedSizeBinaryType.new(4)
+      values = ["0124".b, nil, "abcd".b]
+      assert_equal(values,
+                   ArrowFormat::FixedSizeBinaryArray.new(type, values).to_a)
+    end
+
+    def test_too_small_value_size
+      error = ArgumentError.new("value size must be 4: \"012\"")
+      assert_raise(error) do
+        ArrowFormat::FixedSizeBinaryArray.new(4, ["012".b])
+      end
+    end
+
+    def test_too_large_value_size
+      error = ArgumentError.new("value size must be 4: \"01245\"")
+      assert_raise(error) do
+        ArrowFormat::FixedSizeBinaryArray.new(4, ["01245".b])
+      end
+    end
+  end
+
+  sub_test_case("#==") do
+    def test_no_slice
+      values = ["0124".b, nil, "abcd".b]
+      array1 = ArrowFormat::FixedSizeBinaryArray.new(4, values)
+      array2 = ArrowFormat::FixedSizeBinaryArray.new(4, values)
+      assert_equal(array1, array2)
+    end
+
+    def test_sliced
+      pad = "0000".b
+      values = ["0124".b, nil, "abcd".b]
+      array1 = ArrowFormat::FixedSizeBinaryArray.new(4, values)
+      array2 = ArrowFormat::FixedSizeBinaryArray.new(4, [pad, *values, pad])
+      assert_equal(array1, array2.slice(1, 3))
+    end
+
+    def test_sliced_different_content
+      pad = "0000".b
+      values = ["0124".b, nil, "abcd".b]
+      array1 = ArrowFormat::FixedSizeBinaryArray.new(4, values)
+      array2 = ArrowFormat::FixedSizeBinaryArray.new(4,
+                                                     [pad, pad, *values, pad])
+      assert_not_equal(array1, array2.slice(1, 3))
+    end
+  end
+end