RealA10N/writertoutils

WriterTo Utils

Useful functions & types that extend the functionality of the io.WriterTo interface in Golang.

MultiWriterTo

A simple utility that concatenates multiple io.WriterTo objects, into a single writing stream.

func main() {
    r1 := strings.NewReader("hello, ")  // implements io.WriterTo
    r2 := strings.NewReader("world!") // implements io.WriterTo

    multiWriter := multiwriterto.MultiWriterTo(r1, r2)
    buffer := new(bytes.Buffer)

    // writes "hello, world!" to the buffer!
    n, err := multiWriter.WriteTo(buffer)
}

BinaryMarshalerAdapter

Convert any encoding.BinaryMarshaler interface to a io.WriterTo interface.

func main() {
    marshaler := MyMarshaler() // implements: MarshalBinary() (data []byte, err error)

    writerTo := multiwriterto.BinaryMarshalerAdapter(marshaler)
    buffer := new(bytes.Buffer)

    // calls MarshalBinary() and writes the binary data to the buffer!
    n, err := writerTo.WriteTo(buffer)
}

BufferWriterTo

The behavior of the standard bytes.Buffer writes the buffer content on a call to WriteTo only once, and then it empties (subsequent calls write 0 bytes).

Use BufferWriterTo in the case that you want any call to WriteTo to write the same buffer to the provided writer.

func main() {
    bufferWriterTo := multiwriterto.BufferWriterTo({}byte['h', 'i', '!', '\n'])

    // output 3 lines of 'hi!'
    for i := 0; i < 3; i++ {
    	bufferWriterTo.WriteTo(os.Stdout)
    }
}