isjis(str)
Returns whether input encoding is ISO-2022-JP or not.
# File ext/nkf/lib/kconv.rb, line 173 def isjis(str) /\A [\t\n\r\x20-\x7E]* (?: (?:\x1b \x28 I [\x21-\x7E]* |\x1b \x28 J [\x21-\x7E]* |\x1b \x24 @ (?:[\x21-\x7E]{2})* |\x1b \x24 B (?:[\x21-\x7E]{2})* |\x1b \x24 \x28 D (?:[\x21-\x7E]{2})* )* \x1b \x28 B [\t\n\r\x20-\x7E]* )* \z/ox =~ str.dup.force_encoding('BINARY') ? true : false end