netstring.go

// MIT License
//
// Copyright (c) 2020 Lack
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.

package protorpc

import (
	"encoding/binary"
	"io"
)

// WriteNetString writes data to a big-endian netstring on a Write.
// Size is always a 32-bit unsigned int.
func WriteNetString(w io.Writer, data []byte) (written int, err error) {
	size := make([]byte, 4)
	binary.BigEndian.PutUint32(size, uint32(len(data)))
	if written, err = w.Write(size); err != nil {
		return
	}
	return w.Write(data)
}

// ReadNetString reads data from a big-endian netstring.
func ReadNetString(r io.Reader) (data []byte, err error) {
	sizeBuf := make([]byte, 4)
	_, err = r.Read(sizeBuf)
	if err != nil {
		return nil, err
	}
	size := binary.BigEndian.Uint32(sizeBuf)
	if size == 0 {
		return nil, nil
	}
	data = make([]byte, size)
	_, err = r.Read(data)
	if err != nil {
		return nil, err
	}
	return
}