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