k3s/vendor/github.com/rubiojr/go-vhd/vhd/util.go

74 lines
1.3 KiB
Go

package vhd
import (
"encoding/binary"
"encoding/hex"
"fmt"
"os"
"strings"
"unicode/utf16"
"unicode/utf8"
)
// https://groups.google.com/forum/#!msg/golang-nuts/d0nF_k4dSx4/rPGgfXv6QCoJ
func uuidgen() string {
b := uuidgenBytes()
return fmt.Sprintf("%x-%x-%x-%x-%x",
b[0:4], b[4:6], b[6:8], b[8:10], b[10:])
}
func fmtField(name, value string) {
fmt.Printf("%-25s%s\n", name+":", value)
}
func uuidgenBytes() []byte {
f, err := os.Open("/dev/urandom")
check(err)
b := make([]byte, 16)
f.Read(b)
return b
}
func check(e error) {
if e != nil {
panic(e)
}
}
func hexs(a []byte) string {
return "0x" + hex.EncodeToString(a[:])
}
func uuid(a []byte) string {
return fmt.Sprintf("%08x-%04x-%04x-%04x-%04x",
a[:4],
a[4:6],
a[6:8],
a[8:10],
a[10:16])
}
func uuidToBytes(uuid string) []byte {
s := strings.Replace(uuid, "-", "", -1)
h, err := hex.DecodeString(s)
check(err)
return h
}
/*
utf16BytesToString converts UTF-16 encoded bytes, in big or
little endian byte order, to a UTF-8 encoded string.
http://stackoverflow.com/a/15794113
*/
func utf16BytesToString(b []byte, o binary.ByteOrder) string {
utf := make([]uint16, (len(b)+(2-1))/2)
for i := 0; i+(2-1) < len(b); i += 2 {
utf[i/2] = o.Uint16(b[i:])
}
if len(b)/2 < len(utf) {
utf[len(utf)-1] = utf8.RuneError
}
return string(utf16.Decode(utf))
}