mirror of
https://github.com/strongdm/comply
synced 2024-11-14 11:54:53 +00:00
238 lines
6.1 KiB
Go
238 lines
6.1 KiB
Go
// +build windows
|
|
|
|
// Package guid provides a GUID type. The backing structure for a GUID is
|
|
// identical to that used by the golang.org/x/sys/windows GUID type.
|
|
// There are two main binary encodings used for a GUID, the big-endian encoding,
|
|
// and the Windows (mixed-endian) encoding. See here for details:
|
|
// https://en.wikipedia.org/wiki/Universally_unique_identifier#Encoding
|
|
package guid
|
|
|
|
import (
|
|
"crypto/rand"
|
|
"crypto/sha1"
|
|
"encoding"
|
|
"encoding/binary"
|
|
"fmt"
|
|
"strconv"
|
|
|
|
"golang.org/x/sys/windows"
|
|
)
|
|
|
|
// Variant specifies which GUID variant (or "type") of the GUID. It determines
|
|
// how the entirety of the rest of the GUID is interpreted.
|
|
type Variant uint8
|
|
|
|
// The variants specified by RFC 4122.
|
|
const (
|
|
// VariantUnknown specifies a GUID variant which does not conform to one of
|
|
// the variant encodings specified in RFC 4122.
|
|
VariantUnknown Variant = iota
|
|
VariantNCS
|
|
VariantRFC4122
|
|
VariantMicrosoft
|
|
VariantFuture
|
|
)
|
|
|
|
// Version specifies how the bits in the GUID were generated. For instance, a
|
|
// version 4 GUID is randomly generated, and a version 5 is generated from the
|
|
// hash of an input string.
|
|
type Version uint8
|
|
|
|
var _ = (encoding.TextMarshaler)(GUID{})
|
|
var _ = (encoding.TextUnmarshaler)(&GUID{})
|
|
|
|
// GUID represents a GUID/UUID. It has the same structure as
|
|
// golang.org/x/sys/windows.GUID so that it can be used with functions expecting
|
|
// that type. It is defined as its own type so that stringification and
|
|
// marshaling can be supported. The representation matches that used by native
|
|
// Windows code.
|
|
type GUID windows.GUID
|
|
|
|
// NewV4 returns a new version 4 (pseudorandom) GUID, as defined by RFC 4122.
|
|
func NewV4() (GUID, error) {
|
|
var b [16]byte
|
|
if _, err := rand.Read(b[:]); err != nil {
|
|
return GUID{}, err
|
|
}
|
|
|
|
g := FromArray(b)
|
|
g.setVersion(4) // Version 4 means randomly generated.
|
|
g.setVariant(VariantRFC4122)
|
|
|
|
return g, nil
|
|
}
|
|
|
|
// NewV5 returns a new version 5 (generated from a string via SHA-1 hashing)
|
|
// GUID, as defined by RFC 4122. The RFC is unclear on the encoding of the name,
|
|
// and the sample code treats it as a series of bytes, so we do the same here.
|
|
//
|
|
// Some implementations, such as those found on Windows, treat the name as a
|
|
// big-endian UTF16 stream of bytes. If that is desired, the string can be
|
|
// encoded as such before being passed to this function.
|
|
func NewV5(namespace GUID, name []byte) (GUID, error) {
|
|
b := sha1.New()
|
|
namespaceBytes := namespace.ToArray()
|
|
b.Write(namespaceBytes[:])
|
|
b.Write(name)
|
|
|
|
a := [16]byte{}
|
|
copy(a[:], b.Sum(nil))
|
|
|
|
g := FromArray(a)
|
|
g.setVersion(5) // Version 5 means generated from a string.
|
|
g.setVariant(VariantRFC4122)
|
|
|
|
return g, nil
|
|
}
|
|
|
|
func fromArray(b [16]byte, order binary.ByteOrder) GUID {
|
|
var g GUID
|
|
g.Data1 = order.Uint32(b[0:4])
|
|
g.Data2 = order.Uint16(b[4:6])
|
|
g.Data3 = order.Uint16(b[6:8])
|
|
copy(g.Data4[:], b[8:16])
|
|
return g
|
|
}
|
|
|
|
func (g GUID) toArray(order binary.ByteOrder) [16]byte {
|
|
b := [16]byte{}
|
|
order.PutUint32(b[0:4], g.Data1)
|
|
order.PutUint16(b[4:6], g.Data2)
|
|
order.PutUint16(b[6:8], g.Data3)
|
|
copy(b[8:16], g.Data4[:])
|
|
return b
|
|
}
|
|
|
|
// FromArray constructs a GUID from a big-endian encoding array of 16 bytes.
|
|
func FromArray(b [16]byte) GUID {
|
|
return fromArray(b, binary.BigEndian)
|
|
}
|
|
|
|
// ToArray returns an array of 16 bytes representing the GUID in big-endian
|
|
// encoding.
|
|
func (g GUID) ToArray() [16]byte {
|
|
return g.toArray(binary.BigEndian)
|
|
}
|
|
|
|
// FromWindowsArray constructs a GUID from a Windows encoding array of bytes.
|
|
func FromWindowsArray(b [16]byte) GUID {
|
|
return fromArray(b, binary.LittleEndian)
|
|
}
|
|
|
|
// ToWindowsArray returns an array of 16 bytes representing the GUID in Windows
|
|
// encoding.
|
|
func (g GUID) ToWindowsArray() [16]byte {
|
|
return g.toArray(binary.LittleEndian)
|
|
}
|
|
|
|
func (g GUID) String() string {
|
|
return fmt.Sprintf(
|
|
"%08x-%04x-%04x-%04x-%012x",
|
|
g.Data1,
|
|
g.Data2,
|
|
g.Data3,
|
|
g.Data4[:2],
|
|
g.Data4[2:])
|
|
}
|
|
|
|
// FromString parses a string containing a GUID and returns the GUID. The only
|
|
// format currently supported is the `xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx`
|
|
// format.
|
|
func FromString(s string) (GUID, error) {
|
|
if len(s) != 36 {
|
|
return GUID{}, fmt.Errorf("invalid GUID %q", s)
|
|
}
|
|
if s[8] != '-' || s[13] != '-' || s[18] != '-' || s[23] != '-' {
|
|
return GUID{}, fmt.Errorf("invalid GUID %q", s)
|
|
}
|
|
|
|
var g GUID
|
|
|
|
data1, err := strconv.ParseUint(s[0:8], 16, 32)
|
|
if err != nil {
|
|
return GUID{}, fmt.Errorf("invalid GUID %q", s)
|
|
}
|
|
g.Data1 = uint32(data1)
|
|
|
|
data2, err := strconv.ParseUint(s[9:13], 16, 16)
|
|
if err != nil {
|
|
return GUID{}, fmt.Errorf("invalid GUID %q", s)
|
|
}
|
|
g.Data2 = uint16(data2)
|
|
|
|
data3, err := strconv.ParseUint(s[14:18], 16, 16)
|
|
if err != nil {
|
|
return GUID{}, fmt.Errorf("invalid GUID %q", s)
|
|
}
|
|
g.Data3 = uint16(data3)
|
|
|
|
for i, x := range []int{19, 21, 24, 26, 28, 30, 32, 34} {
|
|
v, err := strconv.ParseUint(s[x:x+2], 16, 8)
|
|
if err != nil {
|
|
return GUID{}, fmt.Errorf("invalid GUID %q", s)
|
|
}
|
|
g.Data4[i] = uint8(v)
|
|
}
|
|
|
|
return g, nil
|
|
}
|
|
|
|
func (g *GUID) setVariant(v Variant) {
|
|
d := g.Data4[0]
|
|
switch v {
|
|
case VariantNCS:
|
|
d = (d & 0x7f)
|
|
case VariantRFC4122:
|
|
d = (d & 0x3f) | 0x80
|
|
case VariantMicrosoft:
|
|
d = (d & 0x1f) | 0xc0
|
|
case VariantFuture:
|
|
d = (d & 0x0f) | 0xe0
|
|
case VariantUnknown:
|
|
fallthrough
|
|
default:
|
|
panic(fmt.Sprintf("invalid variant: %d", v))
|
|
}
|
|
g.Data4[0] = d
|
|
}
|
|
|
|
// Variant returns the GUID variant, as defined in RFC 4122.
|
|
func (g GUID) Variant() Variant {
|
|
b := g.Data4[0]
|
|
if b&0x80 == 0 {
|
|
return VariantNCS
|
|
} else if b&0xc0 == 0x80 {
|
|
return VariantRFC4122
|
|
} else if b&0xe0 == 0xc0 {
|
|
return VariantMicrosoft
|
|
} else if b&0xe0 == 0xe0 {
|
|
return VariantFuture
|
|
}
|
|
return VariantUnknown
|
|
}
|
|
|
|
func (g *GUID) setVersion(v Version) {
|
|
g.Data3 = (g.Data3 & 0x0fff) | (uint16(v) << 12)
|
|
}
|
|
|
|
// Version returns the GUID version, as defined in RFC 4122.
|
|
func (g GUID) Version() Version {
|
|
return Version((g.Data3 & 0xF000) >> 12)
|
|
}
|
|
|
|
// MarshalText returns the textual representation of the GUID.
|
|
func (g GUID) MarshalText() ([]byte, error) {
|
|
return []byte(g.String()), nil
|
|
}
|
|
|
|
// UnmarshalText takes the textual representation of a GUID, and unmarhals it
|
|
// into this GUID.
|
|
func (g *GUID) UnmarshalText(text []byte) error {
|
|
g2, err := FromString(string(text))
|
|
if err != nil {
|
|
return err
|
|
}
|
|
*g = g2
|
|
return nil
|
|
}
|