diff options
Diffstat (limited to 'ruby_1_8_5/lib/readbytes.rb')
-rw-r--r-- | ruby_1_8_5/lib/readbytes.rb | 41 |
1 files changed, 41 insertions, 0 deletions
diff --git a/ruby_1_8_5/lib/readbytes.rb b/ruby_1_8_5/lib/readbytes.rb new file mode 100644 index 0000000000..ebb5fc0bd4 --- /dev/null +++ b/ruby_1_8_5/lib/readbytes.rb @@ -0,0 +1,41 @@ +# TruncatedDataError is raised when IO#readbytes fails to read enough data. + +class TruncatedDataError<IOError + def initialize(mesg, data) # :nodoc: + @data = data + super(mesg) + end + + # The read portion of an IO#readbytes attempt. + attr_reader :data +end + +class IO + # Reads exactly +n+ bytes. + # + # If the data read is nil an EOFError is raised. + # + # If the data read is too short a TruncatedDataError is raised and the read + # data is obtainable via its #data method. + def readbytes(n) + str = read(n) + if str == nil + raise EOFError, "End of file reached" + end + if str.size < n + raise TruncatedDataError.new("data truncated", str) + end + str + end +end + +if __FILE__ == $0 + begin + loop do + print STDIN.readbytes(6) + end + rescue TruncatedDataError + p $!.data + raise + end +end |