/
utils.go
122 lines (103 loc) · 2.34 KB
/
utils.go
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package dnsmsg
import (
"encoding/binary"
"unsafe"
"github.com/IrineSistiana/mosproxy/internal/pool"
)
func copyBuf(b []byte) pool.Buffer {
c := pool.GetBuf(len(b))
copy(c, b)
return c
}
func bytes2StrUnsafe(b []byte) string {
return unsafe.String(unsafe.SliceData(b), len(b))
}
func packByte(b []byte, off int, v byte) (int, error) {
if off+1 <= len(b) {
b[off] = v
off += 1
return off, nil
}
return off, ErrSmallBuffer
}
func packNamePtr(b []byte, off int, v [2]byte) (int, error) {
if off+2 <= len(b) {
copy(b[off:], v[:])
off += 2
return off, nil
}
return off, ErrSmallBuffer
}
func packUint16(b []byte, off int, v uint16) (int, error) {
if off+2 <= len(b) {
binary.BigEndian.PutUint16(b[off:], v)
off += 2
return off, nil
}
return off, ErrSmallBuffer
}
func packUint32(b []byte, off int, v uint32) (int, error) {
if off+4 <= len(b) {
binary.BigEndian.PutUint32(b[off:], v)
off += 4
return off, nil
}
return off, ErrSmallBuffer
}
func packBytes(b []byte, off int, v []byte) (int, error) {
if off+len(v) <= len(b) {
copy(b[off:], v)
off += len(v)
return off, nil
}
return off, ErrSmallBuffer
}
func putUint16(b []byte, v uint16) {
binary.BigEndian.PutUint16(b, v)
}
func unpackUint16(b []byte) uint16 {
return binary.BigEndian.Uint16(b)
}
func unpackUint16Msg(msg []byte, off int) (uint16, int, error) {
buf := msg[off:]
if len(buf) < 2 {
return 0, 0, ErrSmallBuffer
}
return unpackUint16(buf), off + 2, nil
}
func unpackUint32Msg(msg []byte, off int) (uint32, int, error) {
buf := msg[off:]
if len(buf) < 4 {
return 0, 0, ErrSmallBuffer
}
return binary.BigEndian.Uint32(buf), off + 4, nil
}
func unpackBytesMsgToBuffer(msg []byte, off int, l int) (pool.Buffer, int, error) {
buf := msg[off:]
if len(buf) < l {
return nil, 0, ErrSmallBuffer
}
return copyBuf(buf[:l]), off + l, nil
}
func unpackBytesMsg(msg []byte, off int, dst []byte) (int, error) {
buf := msg[off:]
if len(buf) < len(dst) {
return 0, ErrSmallBuffer
}
copy(dst, buf)
return off + len(dst), nil
}
func asciiToLower(s []byte) {
for i, c := range s {
if 'A' <= c && c <= 'Z' {
c += 'a' - 'A'
s[i] = c
}
}
}
func isPrintableLabelChar(b uint8) bool {
return ('a' <= b && b <= 'z') || ('A' <= b && b <= 'Z') || ('0' <= b && b <= '9') || b == '-'
}
type noCopy struct{}
func (*noCopy) Lock() {}
func (*noCopy) Unlock() {}