import (
"bytes"
"encoding/binary"
)
const (
// 支持数据最大长度为 2 << 61
// DataLengthOfLenth = 8
// 支持数据最大长度为 2 << 30
DataLengthOfLenth = 4
)
//通讯协议处理，主要处理封包和解包的过程
type Protocol struct { // 包头
header string
// 包头长度
headerLen int
}
func NewProtocol(packetHeader string) *Protocol { return &Protocol{ header: packetHeader,
headerLen: len([]byte(packetHeader)),
}
}
func (self *Protocol) ReSet(header string) { self.header = header
self.headerLen = len([]byte(header))
}
//封包
func (self *Protocol) Packet(message []byte) []byte { return append(append([]byte(self.header), IntToBytes(len(message))...), message...)
}
//解包
func (self *Protocol) Unpack(buffer []byte) (readerSlice [][]byte, bufferOver []byte) { length := len(buffer)
var i int
for i = 0; i < length; i = i + 1 { if length < i+self.headerLen+DataLengthOfLenth { break
}
if string(buffer[i:i+self.headerLen]) == self.header { messageLength := BytesToInt(buffer[i+self.headerLen : i+self.headerLen+DataLengthOfLenth])
if length < i+self.headerLen+DataLengthOfLenth+messageLength { break
}
data := buffer[i+self.headerLen+DataLengthOfLenth : i+self.headerLen+DataLengthOfLenth+messageLength]
readerSlice = append(readerSlice, data)
i += self.headerLen + DataLengthOfLenth + messageLength - 1
}
}
if i == length { bufferOver = make([]byte, 0)
return
}
bufferOver = buffer[i:]
return
}
//整形转换成字节
// func IntToBytes(n int) []byte {// x := int64(n)
// bytesBuffer := bytes.NewBuffer([]byte{})// binary.Write(bytesBuffer, binary.BigEndian, x)
// return bytesBuffer.Bytes()
// }
// //字节转换成整形
// func BytesToInt(b []byte) int {// bytesBuffer := bytes.NewBuffer(b)
// var x int64
// binary.Read(bytesBuffer, binary.BigEndian, &x)
// return int(x)
// }
//整形转换成字节
func IntToBytes(n int) []byte { x := int32(n)
bytesBuffer := bytes.NewBuffer([]byte{}) binary.Write(bytesBuffer, binary.LittleEndian, x)
return bytesBuffer.Bytes()
}
//字节转换成整形
func BytesToInt(b []byte) int { bytesBuffer := bytes.NewBuffer(b)
var x int32
binary.Read(bytesBuffer, binary.LittleEndian, &x)
return int(x)
}
