marshal.c: add marshal readahead. marshalized Array, Hash and Struct
have size at least number of its elements, marshal readahead will
read the certain readable length and buffer when it needs more bytes.
marshal readahead prevents many calls to IO#getbyte and IO#read,
then it enables performace improvement. [ruby-dev:45637] [Feature #6440]
have size at least number of its elements, marshal readahead will
read the certain readable length and buffer when it needs more bytes.
marshal readahead prevents many calls to IO#getbyte and IO#read,
then it enables performace improvement.
[ruby-dev:45637] [Feature #6440]
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@37772 b2dd03c8-39d4-4d8f-98ff-823fe69b080e