merges r20870 from trunk into ruby_1_9_1.

* io.c (rb_io_extract_encoding_option): "internal_encoding: nil"
  to specify no-transcoding.  and other corner case fixed.
  [ruby-dev:37496]

* hash.c (rb_hash_lookup2): new function to look-up hash with
  default value.

git-svn-id: http://svn.ruby-lang.org/repos/ruby/branches/ruby_1_9_1@20886 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 8 insertions, 2 deletions

diff --git a/hash.c b/hash.c
index 044964c80..a058a00a9 100644
--- a/hash.c
+++ b/hash.c
@@ -463,16 +463,22 @@ rb_hash_aref(VALUE hash, VALUE key)
 }
 
 VALUE
-rb_hash_lookup(VALUE hash, VALUE key)
+rb_hash_lookup2(VALUE hash, VALUE key, VALUE def)
 {
     VALUE val;
 
     if (!RHASH(hash)->ntbl || !st_lookup(RHASH(hash)->ntbl, key, &val)) {
-	return Qnil; /* without Hash#default */
+	return def; /* without Hash#default */
     }
     return val;
 }
 
+VALUE
+rb_hash_lookup(VALUE hash, VALUE key)
+{
+    return rb_hash_lookup2(hash, key, Qnil);
+}
+
 /*
  *  call-seq:
  *     hsh.fetch(key [, default] )       => obj