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// SPDU (Session Protocol Data Unit)
package spdu
import (
"encoding/binary"
"errors"
"io"
"net"
)
// |<-- 2 octets -->|<-- maximum 240 octets -->|
// | header | acse/rose pdu |
// | big endian | |
const maxLen = 240 // max PDU size
type Conn struct{ net.Conn }
func (c Conn) Write(p []byte) (n int, err error) {
size := uint16(len(p))
if size > maxLen {
return 0, errors.New("PDU too big")
}
if err := binary.Write(c.Conn, binary.BigEndian, size); err != nil {
return 0, err
}
return c.Conn.Write(p)
}
func (c Conn) Read(p []byte) (n int, err error) {
var size uint16
if err := binary.Read(c.Conn, binary.BigEndian, &size); err != nil {
return 0, err
}
return c.Conn.Read(p[:size])
}
func ReadAll(r io.Reader) ([]byte, error) {
p := make([]byte, maxLen)
n, err := r.Read(p)
return p[:n], err
}
func Dial(service string) (Conn, error) {
conn, err := net.Dial("tcp", service)
if err != nil {
return Conn{}, err
}
return Conn{conn}, nil
}
|