wintun: Make two-step slicing a one step

Stop relying to Go compiler optimizations and calculate the end offset
directly.

Signed-off-by: Simon Rozman <simon@rozman.si>
This commit is contained in:
Simon Rozman 2019-02-22 16:11:33 +01:00
parent ac4944a708
commit e06a8f8f9f

View File

@ -240,7 +240,7 @@ func (tun *nativeTun) Read(buff []byte, offset int) (int, error) {
packet = packet[:pSize] packet = packet[:pSize]
// Copy data. // Copy data.
copy(buff[offset:], packet[packetExchangeAlignment:][:size]) copy(buff[offset:], packet[packetExchangeAlignment:packetExchangeAlignment+size])
tun.rdBuff.offset += pSize tun.rdBuff.offset += pSize
return int(size), nil return int(size), nil
} }
@ -331,9 +331,9 @@ func (tun *nativeTun) putTunPacket(buff []byte) error {
} }
// Write packet to the exchange buffer. // Write packet to the exchange buffer.
packet := tun.wrBuff.data[tun.wrBuff.offset:][:pSize] packet := tun.wrBuff.data[tun.wrBuff.offset : tun.wrBuff.offset+pSize]
binary.LittleEndian.PutUint32(packet[:4], size) binary.LittleEndian.PutUint32(packet[:4], size)
copy(packet[packetExchangeAlignment:][:size], buff) copy(packet[packetExchangeAlignment:packetExchangeAlignment+size], buff)
tun.wrBuff.packetNum++ tun.wrBuff.packetNum++
tun.wrBuff.offset += pSize tun.wrBuff.offset += pSize