packer-cn/vendor/github.com/mitchellh/go-vnc/pixel_format.go

152 lines
3.2 KiB
Go

package vnc
import (
"bytes"
"encoding/binary"
"io"
)
// PixelFormat describes the way a pixel is formatted for a VNC connection.
//
// See RFC 6143 Section 7.4 for information on each of the fields.
type PixelFormat struct {
BPP uint8
Depth uint8
BigEndian bool
TrueColor bool
RedMax uint16
GreenMax uint16
BlueMax uint16
RedShift uint8
GreenShift uint8
BlueShift uint8
}
func readPixelFormat(r io.Reader, result *PixelFormat) error {
var rawPixelFormat [16]byte
if _, err := io.ReadFull(r, rawPixelFormat[:]); err != nil {
return err
}
var pfBoolByte uint8
brPF := bytes.NewReader(rawPixelFormat[:])
if err := binary.Read(brPF, binary.BigEndian, &result.BPP); err != nil {
return err
}
if err := binary.Read(brPF, binary.BigEndian, &result.Depth); err != nil {
return err
}
if err := binary.Read(brPF, binary.BigEndian, &pfBoolByte); err != nil {
return err
}
if pfBoolByte != 0 {
// Big endian is true
result.BigEndian = true
}
if err := binary.Read(brPF, binary.BigEndian, &pfBoolByte); err != nil {
return err
}
if pfBoolByte != 0 {
// True Color is true. So we also have to read all the color max & shifts.
result.TrueColor = true
if err := binary.Read(brPF, binary.BigEndian, &result.RedMax); err != nil {
return err
}
if err := binary.Read(brPF, binary.BigEndian, &result.GreenMax); err != nil {
return err
}
if err := binary.Read(brPF, binary.BigEndian, &result.BlueMax); err != nil {
return err
}
if err := binary.Read(brPF, binary.BigEndian, &result.RedShift); err != nil {
return err
}
if err := binary.Read(brPF, binary.BigEndian, &result.GreenShift); err != nil {
return err
}
if err := binary.Read(brPF, binary.BigEndian, &result.BlueShift); err != nil {
return err
}
}
return nil
}
func writePixelFormat(format *PixelFormat) ([]byte, error) {
var buf bytes.Buffer
// Byte 1
if err := binary.Write(&buf, binary.BigEndian, format.BPP); err != nil {
return nil, err
}
// Byte 2
if err := binary.Write(&buf, binary.BigEndian, format.Depth); err != nil {
return nil, err
}
var boolByte byte
if format.BigEndian {
boolByte = 1
} else {
boolByte = 0
}
// Byte 3 (BigEndian)
if err := binary.Write(&buf, binary.BigEndian, boolByte); err != nil {
return nil, err
}
if format.TrueColor {
boolByte = 1
} else {
boolByte = 0
}
// Byte 4 (TrueColor)
if err := binary.Write(&buf, binary.BigEndian, boolByte); err != nil {
return nil, err
}
// If we have true color enabled then we have to fill in the rest of the
// structure with the color values.
if format.TrueColor {
if err := binary.Write(&buf, binary.BigEndian, format.RedMax); err != nil {
return nil, err
}
if err := binary.Write(&buf, binary.BigEndian, format.GreenMax); err != nil {
return nil, err
}
if err := binary.Write(&buf, binary.BigEndian, format.BlueMax); err != nil {
return nil, err
}
if err := binary.Write(&buf, binary.BigEndian, format.RedShift); err != nil {
return nil, err
}
if err := binary.Write(&buf, binary.BigEndian, format.GreenShift); err != nil {
return nil, err
}
if err := binary.Write(&buf, binary.BigEndian, format.BlueShift); err != nil {
return nil, err
}
}
return buf.Bytes()[0:16], nil
}