1 files changed, 76 insertions, 0 deletions
diff --git a/lib/btrfs/internal/uuid.go b/lib/btrfs/internal/uuid.go
new file mode 100644
index 0000000..a16d10f
--- /dev/null
+++ b/lib/btrfs/internal/uuid.go
@@ -0,0 +1,76 @@
+// Copyright (C) 2022  Luke Shumaker <lukeshu@lukeshu.com>
+//
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+package util
+
+import (
+	"encoding/hex"
+	"fmt"
+	"strings"
+)
+
+type UUID [16]byte
+
+func (uuid UUID) String() string {
+	str := hex.EncodeToString(uuid[:])
+	return strings.Join([]string{
+		str[:8],
+		str[8:12],
+		str[12:16],
+		str[16:20],
+		str[20:32],
+	}, "-")
+}
+
+func (a UUID) Cmp(b UUID) int {
+	for i := range a {
+		if d := int(a[i]) - int(b[i]); d != 0 {
+			return d
+		}
+	}
+	return 0
+}
+
+func (uuid UUID) Format(f fmt.State, verb rune) {
+	FormatByteArrayStringer(uuid, uuid[:], f, verb)
+}
+
+func ParseUUID(str string) (UUID, error) {
+	var ret UUID
+	j := 0
+	for i := 0; i < len(str); i++ {
+		if j >= len(ret)*2 {
+			return UUID{}, fmt.Errorf("too long to be a UUID: %q|%q", str[:i], str[i:])
+		}
+		c := str[i]
+		var v byte
+		switch {
+		case '0' <= c && c <= '9':
+			v = c - '0'
+		case 'a' <= c && c <= 'f':
+			v = c - 'a' + 10
+		case 'A' <= c && c <= 'F':
+			v = c - 'A' + 10
+		case c == '-':
+			continue
+		default:
+			return UUID{}, fmt.Errorf("illegal byte in UUID: %q|%q|%q", str[:i], str[i:i+1], str[i+1:])
+		}
+		if j%2 == 0 {
+			ret[j/2] = v << 4
+		} else {
+			ret[j/2] = (ret[j/2] & 0xf0) | (v & 0x0f)
+		}
+		j++
+	}
+	return ret, nil
+}
+
+func MustParseUUID(str string) UUID {
+	ret, err := ParseUUID(str)
+	if err != nil {
+		panic(err)
+	}
+	return ret
+}