Add String#byteindex, String#byterindex, and MatchData#byteoffset (#5518)

* Add String#byteindex, String#byterindex, and MatchData#byteoffset [Feature #13110]

Co-authored-by: NARUSE, Yui <naruse@airemix.jp>

1 files changed, 21 insertions, 0 deletions

diff --git a/test/ruby/test_regexp.rb b/test/ruby/test_regexp.rb
index 2bf4649f14..80caa879e4 100644
--- a/test/ruby/test_regexp.rb
+++ b/test/ruby/test_regexp.rb
@@ -424,6 +424,27 @@ class TestRegexp < Test::Unit::TestCase
     assert_equal([2, 3], m.offset(3))
   end
 
+  def test_match_byteoffset_begin_end
+    m = /(?<x>b..)/.match("foobarbaz")
+    assert_equal([3, 6], m.byteoffset("x"))
+    assert_equal(3, m.begin("x"))
+    assert_equal(6, m.end("x"))
+    assert_raise(IndexError) { m.byteoffset("y") }
+    assert_raise(IndexError) { m.byteoffset(2) }
+    assert_raise(IndexError) { m.begin(2) }
+    assert_raise(IndexError) { m.end(2) }
+
+    m = /(?<x>q..)?/.match("foobarbaz")
+    assert_equal([nil, nil], m.byteoffset("x"))
+    assert_equal(nil, m.begin("x"))
+    assert_equal(nil, m.end("x"))
+
+    m = /\A\u3042(.)(.)?(.)\z/.match("\u3042\u3043\u3044")
+    assert_equal([3, 6], m.byteoffset(1))
+    assert_equal([nil, nil], m.byteoffset(2))
+    assert_equal([6, 9], m.byteoffset(3))
+  end
+
   def test_match_to_s
     m = /(?<x>b..)/.match("foobarbaz")
     assert_equal("bar", m.to_s)