IO::Buffer

IO::Buffer is a fast byte queue which is primarily intended for non-blocking I/O applications but is suitable wherever buffering is required. IO::Buffer is compatible with Ruby 1.8/1.9 and Rubinius.

IO::Buffer provides a subset of the methods available in Strings:

>> buf = IO::Buffer.new
=> #<IO::Buffer:0x12fc708>
>> buf << "foo"
=> "foo"
>> buf << "bar"
=> "bar"
>> buf.to_str
=> "foobar"
>> buf.size
=> 6

The IO::Buffer#<< method is an alias for IO::Buffer#append. A prepend method is also available:

>> buf = IO::Buffer.new
=> #<IO::Buffer:0x12f5250>
>> buf.append "bar"
=> "bar"
>> buf.prepend "foo"
=> "foo"
>> buf.append "baz"
=> "baz"
>> buf.to_str
=> "foobarbaz"

IO::Buffer#read can be used to retrieve the contents of a buffer. You can mix reads alongside adding more data to the buffer:

>> buf = IO::Buffer.new
=> #<IO::Buffer:0x12fc5f0>
>> buf << "foo"
=> "foo"
>> buf.read 2
=> "fo"
>> buf << "bar"
=> "bar"
>> buf.read 2
=> "ob"
>> buf << "baz"
=> "baz"
>> buf.read 3
=> "arb"

Finally, IO::Buffer provides methods for performing non-blocking I/O with the contents of the buffer. The IO::Buffer#read_from(IO) method will read as much data as possible from the given IO object until the read would block.

The IO::Buffer#write_to(IO) method writes the contents of the buffer to the given IO object until either the buffer is empty or the write would block:

>> buf = IO::Buffer.new
=> #<IO::Buffer:0x12fc5c8>
>> file = File.open("README")
=> #<File:README>
>> buf.read_from(file)
=> 1713
>> buf.to_str
=> "= IO::Buffer\n\nIO::Buffer is a fast byte queue...

If the file descriptor is not ready for I/O, the Errno::EAGAIN exception is raised indicating no I/O was performed.

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Copyright (c) 2007-12 Tony Arcieri. Distributed under the MIT License. See LICENSE.txt for further details.